Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate ...Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate of composites was established. Then the upper limit of strain rate, restricted by stress equilibrium and constant loading rate, was rationally estimated and confirmed by tests. Within the achievable range of 0.001/s-895/s, it was found that the strength increased first and subsequently decreased as the strain rate increased. This feature was also reflected by the turning point(579/s) of the bilinear model for strength prediction. The transition in failure mechanism, from local opening damage to completely splitting destruction, was mainly responsible for such strain rate effects. And three major failure modes were summarized under microscopic observations: fiber fracture, inter-fiber fracture, and interface delamination. Finally, by introducing a nonlinear damage variable, a simplified ZWT model was developed to characterize the dynamic mechanical response. Excellent agreement was shown between the experimental and simulated results.展开更多
Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007...Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.展开更多
The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exi...The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exist on the Sanjiang Plain, and three of them have been listed as wetlands of international importance to water bird conservation by the Ramsar Convention Bureau. The wetlands of Sanjiang Plain are noteworthy for its rich biodiversity, but they continue to decline in area and deteriorate in quality currently. The main threats or constrains, immediate cause, root cause and required response are analyzed in this paper, and the four aspects opinion such as improvement of watershed management, enhancement of protection and restoration of habitats and biodiversity, alternative livelihoods of rural residents living in and near natural wetland reserve, and reinforcement of capacity building of natural reserves are brought forward as the effective measures for the Sanjiang Plain wetland protection.展开更多
The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. ...The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.展开更多
The Chinese traditional tea culture that has reflected Chinese culture for five thousand years should be presented in the tea packaging design by using Chinese traditional cultural elements to propagate Chinese tradit...The Chinese traditional tea culture that has reflected Chinese culture for five thousand years should be presented in the tea packaging design by using Chinese traditional cultural elements to propagate Chinese traditional cultural artistic conception and lasting appeal.The purpose of this paper is to research how to present the deep cultural inside information and oriental characteristics in packaging design,which can make entire world feel the depth and profound of Chinese culture when the Chinese traditional tea culture go into the international stage.More importantly,a particular packaging design could increase the merchandises' attraction and concentrate people's attention on them.展开更多
Plain Language has made a great difference nowadays. As it turns out, Plain Language works effectively to express clearly, concisely and systematically. However, it is necessary for contemporary practitioners to revie...Plain Language has made a great difference nowadays. As it turns out, Plain Language works effectively to express clearly, concisely and systematically. However, it is necessary for contemporary practitioners to review the origin and development of Plain Language Movement and to examine whether it has thoroughly implemented Plain Language policies in every federal document. Examining a contemporary federal document against the Guidelines for Document Designers reveals existing problems for further development.展开更多
The most essential principle of translation is faithfulness, which includes both the fidelity to the content and the original style. As the masterpiece of Xiao Hong, Hulanhe Zhuan is unique in its local and plain feat...The most essential principle of translation is faithfulness, which includes both the fidelity to the content and the original style. As the masterpiece of Xiao Hong, Hulanhe Zhuan is unique in its local and plain features and distinct language expressions.With the reproduction of plain style in Howard Goldbaltt's translation as the research object, this study makes a contrastive analysis of the style of Hulanhe Zhuan and its English version.展开更多
Pronunciation learning is the key factor in second language acquisition,which is also the soul of the language.Thereforeit is very vital for beginners to learn the right sounds.However,In the second language acquisiti...Pronunciation learning is the key factor in second language acquisition,which is also the soul of the language.Thereforeit is very vital for beginners to learn the right sounds.However,In the second language acquisition,the sounds of learners’first lan-guage unavoidably have some positive and negative transfer on the target language acquisition.To the Chinese learners,as Chineselanguage belongs to Sino-Tibetan system while English belongs to Germanic language system,the negative transfer is much moreobvious.Guanzhong plain lies in the central of Shaanxi province of China.The dialect here belongs to one of the sub-branches ofNorthern Mandrarin Dialect.Which shares little similarities with English in phonetics.The paper bases on the research of 25 stu-dents whose first language are Guanzhong Plain’s dialect to compare the phonemes of two languages in general and to further ana-lyze the negative transfer of Guanzhong Plain’s dialect to English Phonetic and give the related solutions.展开更多
Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of^(226) Ra,^(232)Th,^(40) K and the artificial radi...Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of^(226) Ra,^(232)Th,^(40) K and the artificial radionuclide^(137) Cs were estimated by using high-purity germanium detector. Subsequent values of activity concentrations were used to find terrestrial absorbed dose rate and annual effective doses received by resident of area. The mean radioactivity levels of^(226) Ra,^(232)Th,^(40) K and^(137)Cs were found to be 45.0 ± 1.3,59.6 ± 2.8, 613.8 ± 20.0 and 4.0 ± 0.2 Bq kg^(-1), respectively. Terrestrial absorbed dose rate and annual effective dose received by public were found to be 85.1 n Gy h^(-1)and0.5 m Sv, respectively. The activity concentrations of^(226) Ra,^(232)Th,^(40) K and^(137)Cs and resulting doses obtained for the current study were compared with data available in the literature and with international standards.展开更多
Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current r...Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.展开更多
基金the National Science and Technology Major Project(Grant No.2017-VII-0011-0106)Natural Science Foundation of Heilongjiang Province(Grant No.ZD2019A001).
文摘Experimental investigations on dynamic in-plane compressive behavior of a plain weave composite were performed using the split Hopkinson pressure bar. A quantitative criterion for calculating the constant strain rate of composites was established. Then the upper limit of strain rate, restricted by stress equilibrium and constant loading rate, was rationally estimated and confirmed by tests. Within the achievable range of 0.001/s-895/s, it was found that the strength increased first and subsequently decreased as the strain rate increased. This feature was also reflected by the turning point(579/s) of the bilinear model for strength prediction. The transition in failure mechanism, from local opening damage to completely splitting destruction, was mainly responsible for such strain rate effects. And three major failure modes were summarized under microscopic observations: fiber fracture, inter-fiber fracture, and interface delamination. Finally, by introducing a nonlinear damage variable, a simplified ZWT model was developed to characterize the dynamic mechanical response. Excellent agreement was shown between the experimental and simulated results.
基金This research was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX2–YW–309)the Major State Basic Research Development Program of China (973 Program No. 2004CB418507)
文摘Seasonal dynamics of above- and belowground biomass and nutrient characteristics （nitrogen, carbon, and phosphorus） of Carex lasiocarpa were investigated in the typical wetland of Sanjiang Plain, China from May 2007 to September 2008. The results show that the changes of aboveground biomass during the growing season are best described by the twice function curve model, whereas the changes of belowground biomass follow the exponential increase curve model. Both the organic carbon contents in the above- and belowground plant parts show significant positive linear correlations with the growing time, and the coefficients R2 are 0.983 and 0.746, respectively. The carbon accu-mulations of the above- and belowground plant parts during the growing season show the same dynamics as those of the biomass. However, the nitrogen contents and accumulation in C. lasiocarpa aboveground and belowground parts show exponential increase during the growing season. The dynamics of C. lasiocarpa phosphorus contents follows the twice function curve model, whereas the accumulation of phosphorus shows the linear increase. The ratios of C/N in different parts of C. lasiocarpa fit the negative linear relations with total nitrogen content in the growing season. Moreover, the ratios of C/P in C. lasiocarpa plant also fit the negative linear relations with total phosphorus content. The results show that nitrogen is the primary limiting nutrient for C. lasiocarpa growth as compared with carbon and phosphorus.
文摘The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. It is the largest tract of wetlands in China and East Asia outside of Siberia. 28 wetland nature reserves exist on the Sanjiang Plain, and three of them have been listed as wetlands of international importance to water bird conservation by the Ramsar Convention Bureau. The wetlands of Sanjiang Plain are noteworthy for its rich biodiversity, but they continue to decline in area and deteriorate in quality currently. The main threats or constrains, immediate cause, root cause and required response are analyzed in this paper, and the four aspects opinion such as improvement of watershed management, enhancement of protection and restoration of habitats and biodiversity, alternative livelihoods of rural residents living in and near natural wetland reserve, and reinforcement of capacity building of natural reserves are brought forward as the effective measures for the Sanjiang Plain wetland protection.
文摘The Sanjiang Plain is a vast area of alluvial floodplains and low hills in northeast Heilongjiang Province. Because of the excessive land reclamation in the past, the whole forest area and the quality have decreased. In the view of sustainable development, this paper analyzed the possibilities for Non-timber Forest Product in terms of developing potentialities, markets, social effects and the status of NTFPs in several counties of Sanjiang Plain. The result showed that, active development and management for NTFPs is an optimistic option to how to balance the wetlands conservation and sustainable economic development.
文摘The Chinese traditional tea culture that has reflected Chinese culture for five thousand years should be presented in the tea packaging design by using Chinese traditional cultural elements to propagate Chinese traditional cultural artistic conception and lasting appeal.The purpose of this paper is to research how to present the deep cultural inside information and oriental characteristics in packaging design,which can make entire world feel the depth and profound of Chinese culture when the Chinese traditional tea culture go into the international stage.More importantly,a particular packaging design could increase the merchandises' attraction and concentrate people's attention on them.
文摘Plain Language has made a great difference nowadays. As it turns out, Plain Language works effectively to express clearly, concisely and systematically. However, it is necessary for contemporary practitioners to review the origin and development of Plain Language Movement and to examine whether it has thoroughly implemented Plain Language policies in every federal document. Examining a contemporary federal document against the Guidelines for Document Designers reveals existing problems for further development.
文摘The most essential principle of translation is faithfulness, which includes both the fidelity to the content and the original style. As the masterpiece of Xiao Hong, Hulanhe Zhuan is unique in its local and plain features and distinct language expressions.With the reproduction of plain style in Howard Goldbaltt's translation as the research object, this study makes a contrastive analysis of the style of Hulanhe Zhuan and its English version.
文摘Pronunciation learning is the key factor in second language acquisition,which is also the soul of the language.Thereforeit is very vital for beginners to learn the right sounds.However,In the second language acquisition,the sounds of learners’first lan-guage unavoidably have some positive and negative transfer on the target language acquisition.To the Chinese learners,as Chineselanguage belongs to Sino-Tibetan system while English belongs to Germanic language system,the negative transfer is much moreobvious.Guanzhong plain lies in the central of Shaanxi province of China.The dialect here belongs to one of the sub-branches ofNorthern Mandrarin Dialect.Which shares little similarities with English in phonetics.The paper bases on the research of 25 stu-dents whose first language are Guanzhong Plain’s dialect to compare the phonemes of two languages in general and to further ana-lyze the negative transfer of Guanzhong Plain’s dialect to English Phonetic and give the related solutions.
文摘Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of^(226) Ra,^(232)Th,^(40) K and the artificial radionuclide^(137) Cs were estimated by using high-purity germanium detector. Subsequent values of activity concentrations were used to find terrestrial absorbed dose rate and annual effective doses received by resident of area. The mean radioactivity levels of^(226) Ra,^(232)Th,^(40) K and^(137)Cs were found to be 45.0 ± 1.3,59.6 ± 2.8, 613.8 ± 20.0 and 4.0 ± 0.2 Bq kg^(-1), respectively. Terrestrial absorbed dose rate and annual effective dose received by public were found to be 85.1 n Gy h^(-1)and0.5 m Sv, respectively. The activity concentrations of^(226) Ra,^(232)Th,^(40) K and^(137)Cs and resulting doses obtained for the current study were compared with data available in the literature and with international standards.
基金National Natural Science Foundation of China(Grant Nos.12172179,11802141 and U2341244)National Natural Science Foundation for Young Scientists of China(Grant No.12202207)+3 种基金China Postdoctoral Science Foundation(Grant No.2022M711623)Natural Science Foundation of Jiangsu Province(Grant No.BK20220968)Open Funds for Key Laboratory of Impact and Safety Engineering(Ningbo University),Ministry of Education(Grant No.CJ202201)Open Funds for Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province(Grant No.22kfgk03)。
文摘Aramid fibers,due to their relatively high inter-yarn friction,high strength,high modulus,and other characteristics,have become a typical representative of flexible anti-ballistic materials in modern warfare.Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles,with fewer studies on the coupled effect of both on ballistic performance.This study analyzes how the coupling relationship(or size effect)between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective.Taking plain weave aramid fabric as the research object,considering different diameter projectiles,through a large number of ballistic impact tests and numerical simulations,parameters such as ballistic limit velocity,average energy absorption of fabric,and specific energy absorption ratio(average energy absorption of fabric divided by projectile cross-sectional area)are obtained for ballistic performance analysis.The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows:The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases,indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm;The average ballistic limit velocity at three impact positions,P1,P2,and P3,provides the corresponding ballistic limit velocity for 1000D aramid fabric,which increases with projectile diameter but the rate of increase slows down at an inflection point,which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm;The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm,reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect.The projectile diameter of 12 mm corresponds to the coupling size of 11.159,which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.
