Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rul...Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rule are analyzed and compared. A new combination approach is proposed. Calculate the reliabilities of evidence sources using existing evidences. Construct reliabilities judge matrixes and get the weights of each evidence source. Weight average all inputted evidences. Combine processed evidences with D-S combination rule repeatedly to identify a target. The application in multi-sensor target reeognition as well as the comparison with typical alternatives all validated that this approach can dispose highly conflict evidences efficiently and get reasonable reeognition results rapidly.展开更多
The objective principles of shiology are mainly reflected in three fields as food acquisition, eaters' health and shiance order. Most of the objective principles in the field of food acquisition have been revealed...The objective principles of shiology are mainly reflected in three fields as food acquisition, eaters' health and shiance order. Most of the objective principles in the field of food acquisition have been revealed by agronomy and foodstuff science. This research mainly focuses on 10 principles in the field of eaters' health and shiance order and in addition, there are also five lemmas that extend from the above principles. The 10 principles are the core theory of the shiology knowledge system, which play an important role in the objective principles revealed by human beings and constitute one of the basic principles of human civilization. Compared with the scientific principles of mathematics, physics, chemistry and economics, the principles of shiology have three characteristics as popularity, practicability and survivability. The principles of shiology in the field of eaters' health are all around us, and everyone can understand and master them. Using the principles of shiology can improve the healthy life span of 8 billion people. The principles of shiology in the field of shiance order is an important tool of social governance, which can reduce human social conflicts, reduce social involution, improve overall efficiency of social operation, and maintain the sustainable development of human beings.展开更多
Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extens...Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.展开更多
This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabri...This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabricated fragments are employed to examine the damage under blast shock waves and combined blast and fragments loading on various liquid-filled cylindrical shell structures.The test results are compared to numerical calculations and theoretical analysis for the structure's deformation,the liquid medium's movement,and the pressure waves'propagation characteristics under different liquid-filling methods.The results showed that the filling method influences the blast protection and the struc-ture's energy absorption performance.The external filling method reduces the structural deformation,and the internal filling method increases the damage effect.The gapped internal filling method improves the structure's energy absorption efficiency.The pressure wave loading on the liquid-filled cylindrical shell structure differs depending on filling methods.Explosive shock waves and high-speed fragments show a damage enhancement effect on the liquid-filled cylindrical shell structure,depending on the thickness of the internal liquid container layer.The specific impulse on the inner surface of the cylindrical shell positively correlates to the radial deformation of the cylindrical shell structure,and the external liquid layer limits the radial structural deformation.展开更多
To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with...To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with varying gangue thicknesses and positions.The response patterns of compressive strength,elastic modulus,pre-peak accumulated energy,elastic energy index,and impact energy index were systematically analyzed.Furthermore,a new index for evaluating the impact tendency of gangue-containing coal was proposed,and its effectiveness was verified.The findings are as follows:(1)As the gangue thickness increases,both the compressive strength and the pre-peak energy of the combined structure decrease,whereas the elastic modulus increases accordingly.When the gangue is located in the lower middle position,the combined structure exhibits the lowest compressive strength and elastic modulus but the highest pre peak energy.(2)As the gangue shifts toward the middle position of the combined structure,the failure mode gradually transitions from comple te“crushing”failure to an incomplete“point-type”failure.As gangue thickness further increases,the failure region evolves from overall failure to localized failure,with the degree of failure shifting from complete to incomplete.The K_(crc)value corresponding to“crushing”complete failure is higher and has a stronger impact tendency compared to“point-type”incomplete failure.(3)The proposed comprehensive impact instability evaluation index K_(crc)for the gangue-coal combined structure has shown a significant positive correlation with compressive strength(R_(c))and impact energy index(K_(E)),further verifyi ng its rationality in comprehensively assessing the impact tendency of gangue-containing coal bodies.Applying this index to the evaluation of gangue-containing coal seams provides a more accurate reflection of their impact tendency compared with the residual energy index,which has a wide range of potential applications and practical significance.展开更多
By phenomenological analysis of warm compaction, it is found that, compared with the contribution of particle plastical deformation to densification of powder compact,the particle rearrangement is a dominant densifica...By phenomenological analysis of warm compaction, it is found that, compared with the contribution of particle plastical deformation to densification of powder compact,the particle rearrangement is a dominant densification mechanism for powder warm compaction, and the plastical deformation of particles plays an important role in offering accommodating deformation for particle rearrangement and densifying powder compact at the final stage of pressing.In order to attain density gain as high as possible during warm compaction, six rules for designing warm compacting powder mixtures were proposed in detail.展开更多
To solve the problems of shaving and reusing information in the information system, a rules-based ontology constructing approach from object-relational databases is proposed. A 3-tuple ontology constructing model is p...To solve the problems of shaving and reusing information in the information system, a rules-based ontology constructing approach from object-relational databases is proposed. A 3-tuple ontology constructing model is proposed first. Then, four types of ontology constructing rules including class, property, property characteristics, and property restrictions ave formalized according to the model. Experiment results described in Web ontology language prove that our proposed approach is feasible for applying in the semantic objects project of semantic computing laboratory in UC Irvine. Our approach reduces about twenty percent constructing time compared with the ontology construction from relational databases.展开更多
Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock...Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock combinations. Fifty-four coal–rock combinations were prepared and split equally into groups containing different moisture contents(dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal–rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal–rock combinations and laws of crack propagation.展开更多
Liuwei Dihuang decoction(LW), a classic formula in traditional Chinese medicine(TCM), has been used for nearly one thousand years for various diseases with characteristic features of kidney yin deficiency. LW consists...Liuwei Dihuang decoction(LW), a classic formula in traditional Chinese medicine(TCM), has been used for nearly one thousand years for various diseases with characteristic features of kidney yin deficiency. LW consists of 6herbs including Dihuang[prepared root of Rehmannia glutinosa(Gaertn) DC], Shanyao(rhizome of Dioscorea polystachya Turcz), Shanzhuyu(fruit of Cornus officinalis Siebold Zucc), Mudanpi(root bark of Paeonia × suffruticosa Andrews),Zexie(rhizome of Alisma plantago-aquatica L) and Fuling(scleorotia of Wolfiporia extensa(Peck) Ginns)LW-active fraction combination(LW-AFC) is extracted from LW, it is effective for the treatment of kidney yin deficiency in many animal models. There are 3 fractions in LW-AFC, a polysaccharide fraction(LWB-B), a glycoside fraction(LWD-b) and an oligosaccharide fraction(CA-30). Our previous results indicate that LW-AFC has similar pharmacological effects to LW, modulating the balance of the NIM network. LW-AFC has positive effects in many animal models of kidney deficiency or disturbance of the NIM network. LW-AFC could improve the cognitive ability in Alzheimer′s disease(AD) animal models(APP/PS1, SAMP8), where modulating immune function and balancing the NIM network may play an important role in its cognition improving effects. Our study also showed that LW-AFC had protective effects on stress-induced disturbances of the NIM network. However, the underlying mechanisms remain elusive and need further investigation. OBJECTIVE This study evaluated the effects of LW-AFC and the active fractions(polysaccharide, LWB-B;glycoside, LWD-b;oligosaccharide,CA-30) on corticosterone(Cort)-induced long-term potentiation(LTP) impairment in vivo. METHODS LTP was used to evaluate the synaptic plasticity. LW-AFC was orally administered for seven days. The active fractions were given by either chronic administration(ig, ip, 7 d) or single administration(icv, ig, ip). Cort was injected subcutaneously 1 h before the high-frequency stimulation(HFS) to induce LTP impairment. Moreover, in order to research on the possible effective pathways, an antibiotic cocktail and an immunosuppressant were also used. RESULTS Chronic administration(ig) of LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Single administration(icv, ig, ip) of any of the active fractions had no effect on Cort-induced LTP impairment, while chronic administration(ig, ip) of LWB-B or LWD-b showed positive effects against Cort. Interestingly, CA-30 only showed protective effects via ig administration,and there was little effect when CA-30 was administered ip In addition, when the intestinal microbiota was disrupted by application of the antibiotic cocktail, CA-30 showed little protective effects against Cort. The effects of LW-AFC were also abolished when the immune function was inhibited. In the hippocampal tissue, Cort treatment increased corticosterone and glutamate, and LW-AFC could inhibit the Cort-induced elevation of corticosterone and glutamate;there was little change in D-serine in Cort-treated animals, but LW-AFC could increase the D-serine levels. CONCLUSION LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Their protective effects are unlikely by a direct way, and immune modulation might be the common pathway. CA-30 could protect LTP from impairment via modulating the intestinal microbiota. Decreasing corticosterone and glutamate and increasing D-serine in the Cort-treated animals’ hippocampal tissue might be one of the mechanisms for the neural protective effects of LW-AFC. Further study is needed to understand the underlying mechanisms.展开更多
Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient...Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient concept was adopted for seismic bearing capacity calculations. A multi-wedge translational failure mechanism was used to obtain the seismic bearing capacity factors for different seismic coefficients and various inclined angles. Employing the associated flow rule, numerical results were compared with the published solutions. For bearing capacity factors related to cohesion and equivalent surcharge load, the maximum difference approximates 0.1%. However, the difference of bearing capacity factor related to unit weight is larger. With the two flow rules, the seismic bearing capacity factors were presented in the form of design charts for practical use. The results show that seismic bearing capacity factors related to the cohesion, the equivalent surcharge load and the unit weight increase greatly as the dilatancy angle increases, and that the nonassociated flow rule has important influences on the seismic bearing capacity.展开更多
Electric power system is one of the most important and complex engineering in modern society, supplying main and general power for social production and social life. Meanwhile, since it is a productive system with bo...Electric power system is one of the most important and complex engineering in modern society, supplying main and general power for social production and social life. Meanwhile, since it is a productive system with both high input and output, it has an obvious economic significance to improve its operating efficiency. For an example, an unit is 10 GW scale, if its standard coal consumption can be decreased with 1 g/kW·h, it can save about 5 000 tons standard coal per year. It will be discussed mainly that how to establish optimization model and its numerical algorithm for operating management of the electric power system. The idea on establishing optimization model is how to dispatch work state of units or power plants, so that total cost of fuel consumption for generation is reduced to the minimum. Here the dispatch is to decide which unit or plant to operate, which unit or plant to stop running, how much power should be generated for those operating units or plants at each given time interval.展开更多
Seismic failure mechanisms were investigated for soil slopes subjected to strip load with upper bound method of limit analysis and finite difference method of numerical simulation,considering the influence of associat...Seismic failure mechanisms were investigated for soil slopes subjected to strip load with upper bound method of limit analysis and finite difference method of numerical simulation,considering the influence of associated and nonassociated flow rules.Quasi-static representation of soil inertia effects using a seismic coefficient concept was adopted for seismic failure analysis.Numerical study was conducted to investigate the influences of dilative angle and earthquake on the seismic failure mechanisms for the loaded slope,and the failure mechanisms for different dilation angles were compared.The results show that dilation angle has influences on the seismic failure surfaces,that seismic maximum displacement vector decreases as the dilation angle increases,and that seismic maximum shear strain rate decreases as the dilation angle increases.展开更多
In order to achieve the information fusion in the time domain based on the evidence theory, an evidence combination method in the time domain based on reliability and importance is proposed according to the idea of ev...In order to achieve the information fusion in the time domain based on the evidence theory, an evidence combination method in the time domain based on reliability and importance is proposed according to the idea of evidence discount. Firstly, the distortion of the time-domain evidence is judged based on single exponential smoothing. The real-time reliability of the evidence at the adjacent time is obtained by the real-time reliability assessment method of the evidence based on the credibility decay model.Then, the relative importance of the evidence at the adjacent time is obtained by comprehensively considering improved conflict degree and uncertainty. Finally, based on the criterion of evidence discount and the Dempster’s rule of combination, the evidence combination is carried out to achieve the sequential combination of time-domain evidence. The numerical simulation and analysis show that this method has fully embodied the dynamic characteristics of time-domain evidence combination, and it has strong processing ability for conflict information and anti-disturbing ability.The proposed method has good applicability to information fusion in the time domain.展开更多
There are defects such as the low convergence rate and premature phenomenon on the performance of simple genetic algorithms （SGA） as the values of crossover probability （Pc） and mutation probability （Pro） are fi...There are defects such as the low convergence rate and premature phenomenon on the performance of simple genetic algorithms （SGA） as the values of crossover probability （Pc） and mutation probability （Pro） are fixed. To solve the problems, the fuzzy control method and the genetic algorithms were systematically integrated to create a kind of improved fuzzy adaptive genetic algorithm （FAGA） based on the auto-regulating fuzzy rules （ARFR-FAGA）. By using the fuzzy control method, the values of Pc and Pm were adjusted according to the evolutional process, and the fuzzy rules were optimized by another genetic algorithm. Experimental results in solving the function optimization problems demonstrate that the convergence rate and solution quality of ARFR-FAGA exceed those of SGA, AGA and fuzzy adaptive genetic algorithm based on expertise （EFAGA） obviously in the global search.展开更多
In order to effectively deal with the conflict temporal evidences without affecting the sequential and dynamic characteristics in the multi-sensor target recognition(MSTR) system at the decision making level, this pap...In order to effectively deal with the conflict temporal evidences without affecting the sequential and dynamic characteristics in the multi-sensor target recognition(MSTR) system at the decision making level, this paper proposes a Dempster-Shafer(DS) theory and intuitionistic fuzzy set(IFS) based temporal evidence combination method(DSIFS-TECM). To realize the method,the relationship between DS theory and IFS is firstly analyzed. And then the intuitionistic fuzzy possibility degree of intuitionistic fuzzy value(IFPD-IFV) is defined, and a novel ranking method with isotonicity for IFV is proposed. Finally, a calculation method for relative reliability factor(RRF) is designed based on the proposed ranking method. As a proof of the method, numerical analysis and experimental simulation are performed. The results indicate DSIFS-TECM is capable of dealing with the conflict temporal evidences and sensitive to the changing of time. Furthermore, compared with the existing methods, DSIFS-TECM has stronger ability of anti-interference.展开更多
The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of me...The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of membership functions and membership degrees to get the normative decision table. The regular method of relations and the reduction algorithm of attributes are studied. The reduced relations are presented by the multi-representvalue method and its algorithm is offered. The whole knowledge acquisition process has high degree of automation and the extracted knowledge is true and reliable.展开更多
To investigate the frost-heave properties of silty clay under the combination action of seasonal freezing and artificial freezing, and verify the feasibility of combined freezing, eight combined freezing experiments w...To investigate the frost-heave properties of silty clay under the combination action of seasonal freezing and artificial freezing, and verify the feasibility of combined freezing, eight combined freezing experiments were performed on silty clay with water content (mass fraction) of 23.5% and 28.0%, through developed frost-heave test apparatus, in closed or open system. Two sorts of freezing temperature models, namely, constant and sine models, were applied to artificial freezing. The experimental results indicate that the frost-heave degree in seasonal freezing stage accounts for over 90% of the total in open system and it is up to 95% in closed system; the change of artificial sine-freezing temperature has no influence on the frost-heave degree in closed system, however, slight influence in open system. It is found that the variation of temperature gradient of sine-freezing specimen lags behind that of sine-freezing temperature with half phase; sine-freezing temperature model can reduce frost-heave degree of soil. Brand new technology is proposed for the application of artificial ground freezing and new study field of artificial freezing is created.展开更多
Based on the Reynolds equation with Reynolds boundary conditions, the Castelli method was employed to solve the Reynolds equation for oil lubrication upon bearings. By doing so, a profile of nonlinear oil film force o...Based on the Reynolds equation with Reynolds boundary conditions, the Castelli method was employed to solve the Reynolds equation for oil lubrication upon bearings. By doing so, a profile of nonlinear oil film force of single-pad journal bearings is established. According to the structure of combination journal bearings, nonlinear oil film force of combination journal bearing is obtained by retrieval, interpolation and assembly techniques. As for symmetrical flexible Jeffcott rotor systems supported by combination journal bearings, the nonlinear motions of the center of the rotor are calculated by the self-adaptive Runge-Kutta method and Poincar6 mapping with different rotational speeds. The numerical results show that the system performance is slightly better when the pivot ratio changes from 0.5 to 0.6, and reveals nonlinear phenomena of periodic, period-doubing, quasi-periodic motion, etc.展开更多
A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classe...A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classes, and fuzzy approximations are defined based on them. Three types of relative reducts of maximal tolerance classes are then proposed, and three types of fuzzy decision rules based on the proposed attribute description are defined. The judgment theorems and approximation discernibility functions with respect to them are presented to compute the relative reduct by using Boolean reasoning techniques, from which we can derive optimal fuzzy decision rules from the systems. At last, three types of relative reducts of the system and their computing methods are given.展开更多
基金This project was supported by the National "863" High Technology Research and Development Program of China(2001AA602021)
文摘Evidence theory is widely used in the field of target recognition. The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rule are analyzed and compared. A new combination approach is proposed. Calculate the reliabilities of evidence sources using existing evidences. Construct reliabilities judge matrixes and get the weights of each evidence source. Weight average all inputted evidences. Combine processed evidences with D-S combination rule repeatedly to identify a target. The application in multi-sensor target reeognition as well as the comparison with typical alternatives all validated that this approach can dispose highly conflict evidences efficiently and get reasonable reeognition results rapidly.
文摘The objective principles of shiology are mainly reflected in three fields as food acquisition, eaters' health and shiance order. Most of the objective principles in the field of food acquisition have been revealed by agronomy and foodstuff science. This research mainly focuses on 10 principles in the field of eaters' health and shiance order and in addition, there are also five lemmas that extend from the above principles. The 10 principles are the core theory of the shiology knowledge system, which play an important role in the objective principles revealed by human beings and constitute one of the basic principles of human civilization. Compared with the scientific principles of mathematics, physics, chemistry and economics, the principles of shiology have three characteristics as popularity, practicability and survivability. The principles of shiology in the field of eaters' health are all around us, and everyone can understand and master them. Using the principles of shiology can improve the healthy life span of 8 billion people. The principles of shiology in the field of shiance order is an important tool of social governance, which can reduce human social conflicts, reduce social involution, improve overall efficiency of social operation, and maintain the sustainable development of human beings.
基金Project(52175445)supported by the National Natural Science Foundation of ChinaProject(2022JJ30743)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(2023GK2024)supported by the Key Research and Development Program of Hunan Province,ChinaProject(2023ZZTS0391)supported by the Fundamental Research Funds for the Central Universities of China。
文摘Red-green-blue(RGB)beam combiners are widely used in scenarios such as augmented reality/virtual reality(AR/VR),laser projection,biochemical detection,and other fields.Optical waveguide combiners have attracted extensive attention due to their advantages of small size,high multiplexing efficiency,convenient mass production,and low cost.An RGB beam combiner based on directional couplers is designed,with a core-cladding relative refractive index difference of 0.75%.The RGB beam combiner is optimized from the perspective of parameter optimization.Using the beam propagation method(BPM),the relationship between the performance of the RGB beam combiner and individual parameters is studied,achieving preliminary optimization of the device’s performance.The key parameters of the RGB beam combiner are optimized using the entropy weight-technique for order preference by similarity to an ideal solution TOPSIS method,establishing the optimal parameter scheme and further improving the device’s performance indicators.The results show that after optimization,the multiplexing efficiencies for red,green,and blue lights,as well as the average multiplexing efficiency,reached 99.17%,99.76%,96.63%and 98.52%,respectively.The size of the RGB beam combiner is 4.768 mm×0.062 mm.
基金the National Natural Science Foundation of China(Grant Nos.52371342,52271338,52101378 and 51979277)。
文摘This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments.Bare charge and charge-driven prefabricated fragments are employed to examine the damage under blast shock waves and combined blast and fragments loading on various liquid-filled cylindrical shell structures.The test results are compared to numerical calculations and theoretical analysis for the structure's deformation,the liquid medium's movement,and the pressure waves'propagation characteristics under different liquid-filling methods.The results showed that the filling method influences the blast protection and the struc-ture's energy absorption performance.The external filling method reduces the structural deformation,and the internal filling method increases the damage effect.The gapped internal filling method improves the structure's energy absorption efficiency.The pressure wave loading on the liquid-filled cylindrical shell structure differs depending on filling methods.Explosive shock waves and high-speed fragments show a damage enhancement effect on the liquid-filled cylindrical shell structure,depending on the thickness of the internal liquid container layer.The specific impulse on the inner surface of the cylindrical shell positively correlates to the radial deformation of the cylindrical shell structure,and the external liquid layer limits the radial structural deformation.
基金Project(52274130)supported by the National Natural Science Foundation of ChinaProject(ZR2024ZD22)supported by the Major Basic Research Project of the Shandong Provincial Natural Science Foundation,China+1 种基金Project(2023375)supported by the Guizhou University Research and Innovation Team,ChinaProject(LH[2024]-026)supported by the Guizhou Science and Technology Plan Project,China。
文摘To investigate the mechanical response during failure and the impact tendency characteristics of gangue-coal combined structure,uniaxial compression tests were conducted on nine groups of combined structures,each with varying gangue thicknesses and positions.The response patterns of compressive strength,elastic modulus,pre-peak accumulated energy,elastic energy index,and impact energy index were systematically analyzed.Furthermore,a new index for evaluating the impact tendency of gangue-containing coal was proposed,and its effectiveness was verified.The findings are as follows:(1)As the gangue thickness increases,both the compressive strength and the pre-peak energy of the combined structure decrease,whereas the elastic modulus increases accordingly.When the gangue is located in the lower middle position,the combined structure exhibits the lowest compressive strength and elastic modulus but the highest pre peak energy.(2)As the gangue shifts toward the middle position of the combined structure,the failure mode gradually transitions from comple te“crushing”failure to an incomplete“point-type”failure.As gangue thickness further increases,the failure region evolves from overall failure to localized failure,with the degree of failure shifting from complete to incomplete.The K_(crc)value corresponding to“crushing”complete failure is higher and has a stronger impact tendency compared to“point-type”incomplete failure.(3)The proposed comprehensive impact instability evaluation index K_(crc)for the gangue-coal combined structure has shown a significant positive correlation with compressive strength(R_(c))and impact energy index(K_(E)),further verifyi ng its rationality in comprehensively assessing the impact tendency of gangue-containing coal bodies.Applying this index to the evaluation of gangue-containing coal seams provides a more accurate reflection of their impact tendency compared with the residual energy index,which has a wide range of potential applications and practical significance.
文摘By phenomenological analysis of warm compaction, it is found that, compared with the contribution of particle plastical deformation to densification of powder compact,the particle rearrangement is a dominant densification mechanism for powder warm compaction, and the plastical deformation of particles plays an important role in offering accommodating deformation for particle rearrangement and densifying powder compact at the final stage of pressing.In order to attain density gain as high as possible during warm compaction, six rules for designing warm compacting powder mixtures were proposed in detail.
基金supported by the National Natural Science Foundation of China (60471055)the National "863" High Technology Research and Development Program of China (2007AA01Z443)
文摘To solve the problems of shaving and reusing information in the information system, a rules-based ontology constructing approach from object-relational databases is proposed. A 3-tuple ontology constructing model is proposed first. Then, four types of ontology constructing rules including class, property, property characteristics, and property restrictions ave formalized according to the model. Experiment results described in Web ontology language prove that our proposed approach is feasible for applying in the semantic objects project of semantic computing laboratory in UC Irvine. Our approach reduces about twenty percent constructing time compared with the ontology construction from relational databases.
基金Project(2014QNB31)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(51674248)supported by the National Natural Science Foundation of ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China
文摘Tackling the problems of underground water storage in collieries in arid regions requires knowledge of the effect of water intrusion and loading rate on the mechanical properties of and crack development in coal–rock combinations. Fifty-four coal–rock combinations were prepared and split equally into groups containing different moisture contents(dry, natural moisture and saturated) to conduct acoustic emission testing under uniaxial compression with loading rates ranging from 0.1 mm/min to 0.6 mm/min. The results show that the peak stress and strength-softening modulus, elastic modulus, strain-softening modulus, and post-peak modulus partly decrease with increasing moisture content and loading rate. In contrast, peak strain increases with increasing moisture content and fluctuates with rising loading rate. More significantly, the relationship between stiffness and stress, combined with accumulated counts of acoustic emission, can be used to precisely predict all phases of crack propagation. This is helpful in studying the impact of moisture content and loading rate on crack propagation and accurately calculating mechanical properties. We also determined that the stress thresholds of crack closure, crack initiation, and crack damage do not vary with changes of moisture content and loading rate, constituting 15.22%, 32.20%, and 80.98% of peak stress, respectively. These outcomes assist in developing approaches to water storage in coal mines, determining the necessary width of waterproof coal–rock pillars, and methods of supporting water-enriched roadways, while also advances understanding the mechanical properties of coal–rock combinations and laws of crack propagation.
文摘Liuwei Dihuang decoction(LW), a classic formula in traditional Chinese medicine(TCM), has been used for nearly one thousand years for various diseases with characteristic features of kidney yin deficiency. LW consists of 6herbs including Dihuang[prepared root of Rehmannia glutinosa(Gaertn) DC], Shanyao(rhizome of Dioscorea polystachya Turcz), Shanzhuyu(fruit of Cornus officinalis Siebold Zucc), Mudanpi(root bark of Paeonia × suffruticosa Andrews),Zexie(rhizome of Alisma plantago-aquatica L) and Fuling(scleorotia of Wolfiporia extensa(Peck) Ginns)LW-active fraction combination(LW-AFC) is extracted from LW, it is effective for the treatment of kidney yin deficiency in many animal models. There are 3 fractions in LW-AFC, a polysaccharide fraction(LWB-B), a glycoside fraction(LWD-b) and an oligosaccharide fraction(CA-30). Our previous results indicate that LW-AFC has similar pharmacological effects to LW, modulating the balance of the NIM network. LW-AFC has positive effects in many animal models of kidney deficiency or disturbance of the NIM network. LW-AFC could improve the cognitive ability in Alzheimer′s disease(AD) animal models(APP/PS1, SAMP8), where modulating immune function and balancing the NIM network may play an important role in its cognition improving effects. Our study also showed that LW-AFC had protective effects on stress-induced disturbances of the NIM network. However, the underlying mechanisms remain elusive and need further investigation. OBJECTIVE This study evaluated the effects of LW-AFC and the active fractions(polysaccharide, LWB-B;glycoside, LWD-b;oligosaccharide,CA-30) on corticosterone(Cort)-induced long-term potentiation(LTP) impairment in vivo. METHODS LTP was used to evaluate the synaptic plasticity. LW-AFC was orally administered for seven days. The active fractions were given by either chronic administration(ig, ip, 7 d) or single administration(icv, ig, ip). Cort was injected subcutaneously 1 h before the high-frequency stimulation(HFS) to induce LTP impairment. Moreover, in order to research on the possible effective pathways, an antibiotic cocktail and an immunosuppressant were also used. RESULTS Chronic administration(ig) of LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Single administration(icv, ig, ip) of any of the active fractions had no effect on Cort-induced LTP impairment, while chronic administration(ig, ip) of LWB-B or LWD-b showed positive effects against Cort. Interestingly, CA-30 only showed protective effects via ig administration,and there was little effect when CA-30 was administered ip In addition, when the intestinal microbiota was disrupted by application of the antibiotic cocktail, CA-30 showed little protective effects against Cort. The effects of LW-AFC were also abolished when the immune function was inhibited. In the hippocampal tissue, Cort treatment increased corticosterone and glutamate, and LW-AFC could inhibit the Cort-induced elevation of corticosterone and glutamate;there was little change in D-serine in Cort-treated animals, but LW-AFC could increase the D-serine levels. CONCLUSION LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment. Their protective effects are unlikely by a direct way, and immune modulation might be the common pathway. CA-30 could protect LTP from impairment via modulating the intestinal microbiota. Decreasing corticosterone and glutamate and increasing D-serine in the Cort-treated animals’ hippocampal tissue might be one of the mechanisms for the neural protective effects of LW-AFC. Further study is needed to understand the underlying mechanisms.
基金Project(200550) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of ChinaProject(05-0686) supported by the Program for New Century Excellent Talents in University
文摘Seismic bearing capacity factors of a strip footing placed on soil slope were determined with both associated and nonassociated flow rules. Quasi-static representation of earthquake effects using a seismic coefficient concept was adopted for seismic bearing capacity calculations. A multi-wedge translational failure mechanism was used to obtain the seismic bearing capacity factors for different seismic coefficients and various inclined angles. Employing the associated flow rule, numerical results were compared with the published solutions. For bearing capacity factors related to cohesion and equivalent surcharge load, the maximum difference approximates 0.1%. However, the difference of bearing capacity factor related to unit weight is larger. With the two flow rules, the seismic bearing capacity factors were presented in the form of design charts for practical use. The results show that seismic bearing capacity factors related to the cohesion, the equivalent surcharge load and the unit weight increase greatly as the dilatancy angle increases, and that the nonassociated flow rule has important influences on the seismic bearing capacity.
文摘Electric power system is one of the most important and complex engineering in modern society, supplying main and general power for social production and social life. Meanwhile, since it is a productive system with both high input and output, it has an obvious economic significance to improve its operating efficiency. For an example, an unit is 10 GW scale, if its standard coal consumption can be decreased with 1 g/kW·h, it can save about 5 000 tons standard coal per year. It will be discussed mainly that how to establish optimization model and its numerical algorithm for operating management of the electric power system. The idea on establishing optimization model is how to dispatch work state of units or power plants, so that total cost of fuel consumption for generation is reduced to the minimum. Here the dispatch is to decide which unit or plant to operate, which unit or plant to stop running, how much power should be generated for those operating units or plants at each given time interval.
基金Project(200550) supported by the Foundation for the Author of National Excellent Doctoral Dissertation of ChinaProject(200631878557) supported by the West Traffic of Science and Technology,China
文摘Seismic failure mechanisms were investigated for soil slopes subjected to strip load with upper bound method of limit analysis and finite difference method of numerical simulation,considering the influence of associated and nonassociated flow rules.Quasi-static representation of soil inertia effects using a seismic coefficient concept was adopted for seismic failure analysis.Numerical study was conducted to investigate the influences of dilative angle and earthquake on the seismic failure mechanisms for the loaded slope,and the failure mechanisms for different dilation angles were compared.The results show that dilation angle has influences on the seismic failure surfaces,that seismic maximum displacement vector decreases as the dilation angle increases,and that seismic maximum shear strain rate decreases as the dilation angle increases.
基金supported by the National Natural Science Foundation of China(71571190 71601183+1 种基金 L1534031)the Shanxi Province Natural Science Foundation of China(2014JQ2-7045)
文摘In order to achieve the information fusion in the time domain based on the evidence theory, an evidence combination method in the time domain based on reliability and importance is proposed according to the idea of evidence discount. Firstly, the distortion of the time-domain evidence is judged based on single exponential smoothing. The real-time reliability of the evidence at the adjacent time is obtained by the real-time reliability assessment method of the evidence based on the credibility decay model.Then, the relative importance of the evidence at the adjacent time is obtained by comprehensively considering improved conflict degree and uncertainty. Finally, based on the criterion of evidence discount and the Dempster’s rule of combination, the evidence combination is carried out to achieve the sequential combination of time-domain evidence. The numerical simulation and analysis show that this method has fully embodied the dynamic characteristics of time-domain evidence combination, and it has strong processing ability for conflict information and anti-disturbing ability.The proposed method has good applicability to information fusion in the time domain.
基金Project(60574030) supported by the National Natural Science Foundation of ChinaKey Project(60634020) supported by the National Natural Science Foundation of China
文摘There are defects such as the low convergence rate and premature phenomenon on the performance of simple genetic algorithms （SGA） as the values of crossover probability （Pc） and mutation probability （Pro） are fixed. To solve the problems, the fuzzy control method and the genetic algorithms were systematically integrated to create a kind of improved fuzzy adaptive genetic algorithm （FAGA） based on the auto-regulating fuzzy rules （ARFR-FAGA）. By using the fuzzy control method, the values of Pc and Pm were adjusted according to the evolutional process, and the fuzzy rules were optimized by another genetic algorithm. Experimental results in solving the function optimization problems demonstrate that the convergence rate and solution quality of ARFR-FAGA exceed those of SGA, AGA and fuzzy adaptive genetic algorithm based on expertise （EFAGA） obviously in the global search.
基金supported by the National Natural Science Foundation of China(61272011)
文摘In order to effectively deal with the conflict temporal evidences without affecting the sequential and dynamic characteristics in the multi-sensor target recognition(MSTR) system at the decision making level, this paper proposes a Dempster-Shafer(DS) theory and intuitionistic fuzzy set(IFS) based temporal evidence combination method(DSIFS-TECM). To realize the method,the relationship between DS theory and IFS is firstly analyzed. And then the intuitionistic fuzzy possibility degree of intuitionistic fuzzy value(IFPD-IFV) is defined, and a novel ranking method with isotonicity for IFV is proposed. Finally, a calculation method for relative reliability factor(RRF) is designed based on the proposed ranking method. As a proof of the method, numerical analysis and experimental simulation are performed. The results indicate DSIFS-TECM is capable of dealing with the conflict temporal evidences and sensitive to the changing of time. Furthermore, compared with the existing methods, DSIFS-TECM has stronger ability of anti-interference.
基金the National Natural Science Foundation of China (50275113).
文摘The basic principles of IF/THEN rules in rough set theory are analyzed first, and then the automatic process of knowledge acquisition is given. The numerical data is qualitatively processed by the classification of membership functions and membership degrees to get the normative decision table. The regular method of relations and the reduction algorithm of attributes are studied. The reduced relations are presented by the multi-representvalue method and its algorithm is offered. The whole knowledge acquisition process has high degree of automation and the extracted knowledge is true and reliable.
基金Project(40571032) supported by the National Natural Science Foundation of ChinaProject(2006G011-B-3) supported by Science Studies and Development Plan Foundation of Railway Ministry
文摘To investigate the frost-heave properties of silty clay under the combination action of seasonal freezing and artificial freezing, and verify the feasibility of combined freezing, eight combined freezing experiments were performed on silty clay with water content (mass fraction) of 23.5% and 28.0%, through developed frost-heave test apparatus, in closed or open system. Two sorts of freezing temperature models, namely, constant and sine models, were applied to artificial freezing. The experimental results indicate that the frost-heave degree in seasonal freezing stage accounts for over 90% of the total in open system and it is up to 95% in closed system; the change of artificial sine-freezing temperature has no influence on the frost-heave degree in closed system, however, slight influence in open system. It is found that the variation of temperature gradient of sine-freezing specimen lags behind that of sine-freezing temperature with half phase; sine-freezing temperature model can reduce frost-heave degree of soil. Brand new technology is proposed for the application of artificial ground freezing and new study field of artificial freezing is created.
基金Project(2007CB707706) supported by the National Basic Research Program of China Projects(51075327,10972179) supported by the National Natural Science Foundation of China+2 种基金 Project(SKLMT-KFKT-201011) supported by Open Foundation of State Key Laboratory of Mechanical Transmission,China Projects(2009JQ7006,2007E203) supported by the Natural Science Foundation of Shaanxi Province of China Projects(09JK680,07JK340) supported by the Natural Science Foundation of Department of Education of Shaanxi Province of China
文摘Based on the Reynolds equation with Reynolds boundary conditions, the Castelli method was employed to solve the Reynolds equation for oil lubrication upon bearings. By doing so, a profile of nonlinear oil film force of single-pad journal bearings is established. According to the structure of combination journal bearings, nonlinear oil film force of combination journal bearing is obtained by retrieval, interpolation and assembly techniques. As for symmetrical flexible Jeffcott rotor systems supported by combination journal bearings, the nonlinear motions of the center of the rotor are calculated by the self-adaptive Runge-Kutta method and Poincar6 mapping with different rotational speeds. The numerical results show that the system performance is slightly better when the pivot ratio changes from 0.5 to 0.6, and reveals nonlinear phenomena of periodic, period-doubing, quasi-periodic motion, etc.
基金supported by the National Natural Science Foundation of China (61070241)the Natural Science Foundation of Shandong Province (ZR2010FM035)Science Research Foundation of University of Jinan (XKY0808)
文摘A new approach to knowledge acquisition in incomplete information system with fuzzy decisions is proposed. In such incomplete information system, the universe of discourse is classified by the maximal tolerance classes, and fuzzy approximations are defined based on them. Three types of relative reducts of maximal tolerance classes are then proposed, and three types of fuzzy decision rules based on the proposed attribute description are defined. The judgment theorems and approximation discernibility functions with respect to them are presented to compute the relative reduct by using Boolean reasoning techniques, from which we can derive optimal fuzzy decision rules from the systems. At last, three types of relative reducts of the system and their computing methods are given.
