This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
Addressing the critical detection range limitation in active electrosensing(AES)for underwater sensing,this study proposes an enhanced AES system via novel array optimization.While AES offers advantages like interfere...Addressing the critical detection range limitation in active electrosensing(AES)for underwater sensing,this study proposes an enhanced AES system via novel array optimization.While AES offers advantages like interference immunity,acoustic stealth detection,and low cost,its short range restricts applicability.A target perturbation model under differential signal acquisition reveals that signal strength increases with local electric field intensity,target size,differential channel spacing,and conductivity contrast,but decreases with target-electrode distance.To extend detection,novel array configurations were explored.Simulations demonstrate that both rectangular and offset arrays significantly outperform the traditional collinear layout.Specifically,an offset array(with 8 m transmitting–receiving spacing)achieved an effective detection range enhancement exceeding 83%under the same distortion threshold while maintaining simplified electrode structure.Experimental validation confirmed a 100%increase in maximum detection distance to 5 m under identical noise thresholds compared to the collinear array.Furthermore,a fully connected neural network-based localization model achieved a mean positioning error of 14.12 cm at 3.15 m in static scenarios.In dynamic scenarios within 1–3 m,mean errors were controlled between 13.19 cm and 27.56 cm.Mechanistic analysis indicates that increasing the array baseline enhances the signal-to-noise ratio by simultaneously suppressing near-field environmental noise and amplifying far-field signal reception.Structural innovations in array design enabled this study to significantly expand the detection range of AES systems without compromising cost efficiency.These advancements directly promote the engineering application of AES technology,offering critical technical support for underwater defense security monitoring,long-range early warning systems,and maritime rights protection.展开更多
A reversed-phase high-performance liquid chromatography(HPLC)method was developed for the direct determination of docosahexaenoic acid(DHA)in sturgeon caviar extract.The assay employed n-hexane extraction combined wit...A reversed-phase high-performance liquid chromatography(HPLC)method was developed for the direct determination of docosahexaenoic acid(DHA)in sturgeon caviar extract.The assay employed n-hexane extraction combined with gradient elution(ZORBAX SB-C18 column),with data collected using a diode array detector.The content was calculated by external standard method and validated against the national standard(GB 5009.168-2016).The study also measured DPPH free radical scavenging capacity and moisture retention rate across different DHA concentration groups.The results demonstrate that the proposed method exhibits excellent linearity(r=0.9997),with recovery rates ranging from 92.1% to 101.1% and relative standard deviations(RSD)of 2.23% to 3.92%.Compared to the national standard method,the relative deviation was 0.67% to 1.68%.At specific test concentrations,the high-DHA group shows significantly higher moisture retention(100.48%),hygroscopicity(100.85%),and DPPH scavenging efficiency(57.46%)than the low-DHA group(10.33%,11.76%,and 3.71%).The RP-HPLC method developed in this study simplifies DHA detection procedures with simple reagents and reliable results,making it suitable for rapid qualitative identification and quantitative analysis of target components in caviar extract quality control.The DPPH experiment further reveals the correlation between DHA content and antioxidant efficacy in sturgeon caviar extracts,providing scientific evidence for developing functional cosmetics.展开更多
In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(...In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(x)-C)has been identified as the key active site in SACs.Although methods for preparing SACs have been extensively reported,a systematic summary of the direct construction of M-N_(x)-C,espe-cially unconventional metal-nitrogen-carbon(UM-N_(x)-C,x≠4),on SACs for PS non-radical activation has still not been reported.The role of the M-N_(x)-C active sites on PS non-radical activation is discussed and methods for the formation of M-N_(x)-C and UM-N_(x)-C active sites in SACs and the effect of catalyst carriers such as carbon nitride(g-C_(3)N_(4)),MOFs,COFs,and other car-bon materials are reviewed.Direct and indirect methods,especially for UM-N_(x)-C active site formation,are also elaborated.Factors affecting the formation of a M-N_(x)-C active site on SACs are also discussed.Prospects for the use of M-N_(x)-C active sites for the non-radical activation of PS by SACs to remove organic contaminants from wastewater are evaluated.展开更多
Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active...Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.展开更多
A cooperative guidance law is proposed in a two-ontwo engagement scenario with large-heading-errors by choosing zero-effort miss distance as a sliding surface,which consists of an attacker,a protector,a defender,and a...A cooperative guidance law is proposed in a two-ontwo engagement scenario with large-heading-errors by choosing zero-effort miss distance as a sliding surface,which consists of an attacker,a protector,a defender,and a target,based on fixed-time sliding mode control theory.Based on the nonlinear method of fixed-time sliding mode control,the performance of the cooperative guidance law remains satisfactory even with large-heading-errors scenarios where the linearization-based approaches might be invalid.By virtue of this law,the attacker pursues the target with the assistance of the protector,which can intercept the defender in the engagement scenario.Furthermore,if the attacker is intercepted by the defender,the guidance law of the protector could guarantee that the protector attacks the target.A robust adaptive term is included in the guidance law to deal with the case of the unknown disturbance upper bound of the defender-target team.Finally,the feasibility of the guidance law is verified by nonlinear numerical simulations,and the superiority of it is illustrated by comparing with the linearization guidance law.展开更多
Because of an unfortunate mistake by authors,the Project(5227010679)of Foundation item was wrong.The corrected Project is shown as follows:Project(52271073).
This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strate...This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strategy to reject unknown disturbances and uncertainties.However,its control performance is limited because standard extended state observer(ESO)struggles to effectively estimate time-varying disturbances.The emergence of high-order ESO(HESO)alleviates the limitation.Unfortunately,it deteriorates the noise suppression capability when the disturbance rejection is enhanced.To tackle this challenge,an improved ADRC with cascade HESO(CHESO)is proposed.A comprehensive theoretical analysis associated with the performance of HESO is given for the first time.The presented analyses provide an intuitive understanding of the performance of HESO.Then,a novel CHESO is developed.The convergence of CHESO is proved via input-to-state stable theory.Extensive frequency domain analyses indicate that CHESO has stronger disturbance rejection and high-frequency noise attenuation performance than ESO and HESO without increasing the observer bandwidth.Comparative simulations conducted on a servo control system validate the effectiveness and preponderance of the proposed method.展开更多
为弥补现有开采沉陷预测程序在可视化表达中的缺陷,采用VB和SURFER的Active X Automation技术开发了基于概率积分法的开采沉陷预测分析系统。通过VB语言操纵SURFER内核程序实现开采沉陷的各种移动变形等值线、三维表面图及剖面图制作和...为弥补现有开采沉陷预测程序在可视化表达中的缺陷,采用VB和SURFER的Active X Automation技术开发了基于概率积分法的开采沉陷预测分析系统。通过VB语言操纵SURFER内核程序实现开采沉陷的各种移动变形等值线、三维表面图及剖面图制作和数据分析的自动化。以山东某煤矿多工作面、多煤层开采沉陷预计对所建立分析系统进行验证。结果表明,采用VB与SURFER结合用于开采沉陷的预测分析,能够满足工程需要,并且能极大地提高工作效率,减少程序开发的工作量,实现开采沉陷预测分析图件制作的专业化、自动化。展开更多
分数阶Active Demons(fractional active demons,FAD)算法是图像非刚性配准的有效方法,并且能解决灰度均匀和弱纹理图像配准精度低,优化易陷入局部极小而导致的配准速度缓慢问题,但是该算法中分数阶最佳阶次的寻找需要通过多次实验人工...分数阶Active Demons(fractional active demons,FAD)算法是图像非刚性配准的有效方法,并且能解决灰度均匀和弱纹理图像配准精度低,优化易陷入局部极小而导致的配准速度缓慢问题,但是该算法中分数阶最佳阶次的寻找需要通过多次实验人工选取,缺乏阶次自适应性.针对该问题,提出了基于多分辨率和自适应分数阶的Active Demons算法,该算法首先根据图像梯度模值和信息熵,构建了自适应分数阶阶次的数学模型,基于该模型自动计算出分数阶的最佳阶次和微分动态模板;然后将多分辨率策略加入到自适应分数阶Active Demons算法中,进一步提高了图像配准效率.理论分析和实验结果均表明:提出的算法可用于灰度均匀、弱边缘和弱纹理图像的配准,能根据图像的局部特征自适应计算最佳分数阶阶次,并避免了算法陷入局部最优,从而提高了图像配准的精度和效率.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
A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous...A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.展开更多
OBJECTIVE Liuwei Dihuang Decoction(LW)-active fraction combination(LW-AFC,consist of 3 fractions polysaccharide,LWB-B;glycoside,LWD-b;oligosaccharide,CA-30)is extracted from LW,it is effective for the treatment of kid...OBJECTIVE Liuwei Dihuang Decoction(LW)-active fraction combination(LW-AFC,consist of 3 fractions polysaccharide,LWB-B;glycoside,LWD-b;oligosaccharide,CA-30)is extracted from LW,it is effective for the treatment of kidney yin deficiency in many animal models.This study evaluated the effects and mechanisms of LW-AFC and the active fractions 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 1h 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 Cort and glutamate,and LW-AFC could inhibit the Cort-induced elevation of Cort 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 Cort 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
文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
基金supported in part by National Natural Science Foundation of China(Grant No.62273075).
文摘Addressing the critical detection range limitation in active electrosensing(AES)for underwater sensing,this study proposes an enhanced AES system via novel array optimization.While AES offers advantages like interference immunity,acoustic stealth detection,and low cost,its short range restricts applicability.A target perturbation model under differential signal acquisition reveals that signal strength increases with local electric field intensity,target size,differential channel spacing,and conductivity contrast,but decreases with target-electrode distance.To extend detection,novel array configurations were explored.Simulations demonstrate that both rectangular and offset arrays significantly outperform the traditional collinear layout.Specifically,an offset array(with 8 m transmitting–receiving spacing)achieved an effective detection range enhancement exceeding 83%under the same distortion threshold while maintaining simplified electrode structure.Experimental validation confirmed a 100%increase in maximum detection distance to 5 m under identical noise thresholds compared to the collinear array.Furthermore,a fully connected neural network-based localization model achieved a mean positioning error of 14.12 cm at 3.15 m in static scenarios.In dynamic scenarios within 1–3 m,mean errors were controlled between 13.19 cm and 27.56 cm.Mechanistic analysis indicates that increasing the array baseline enhances the signal-to-noise ratio by simultaneously suppressing near-field environmental noise and amplifying far-field signal reception.Structural innovations in array design enabled this study to significantly expand the detection range of AES systems without compromising cost efficiency.These advancements directly promote the engineering application of AES technology,offering critical technical support for underwater defense security monitoring,long-range early warning systems,and maritime rights protection.
文摘A reversed-phase high-performance liquid chromatography(HPLC)method was developed for the direct determination of docosahexaenoic acid(DHA)in sturgeon caviar extract.The assay employed n-hexane extraction combined with gradient elution(ZORBAX SB-C18 column),with data collected using a diode array detector.The content was calculated by external standard method and validated against the national standard(GB 5009.168-2016).The study also measured DPPH free radical scavenging capacity and moisture retention rate across different DHA concentration groups.The results demonstrate that the proposed method exhibits excellent linearity(r=0.9997),with recovery rates ranging from 92.1% to 101.1% and relative standard deviations(RSD)of 2.23% to 3.92%.Compared to the national standard method,the relative deviation was 0.67% to 1.68%.At specific test concentrations,the high-DHA group shows significantly higher moisture retention(100.48%),hygroscopicity(100.85%),and DPPH scavenging efficiency(57.46%)than the low-DHA group(10.33%,11.76%,and 3.71%).The RP-HPLC method developed in this study simplifies DHA detection procedures with simple reagents and reliable results,making it suitable for rapid qualitative identification and quantitative analysis of target components in caviar extract quality control.The DPPH experiment further reveals the correlation between DHA content and antioxidant efficacy in sturgeon caviar extracts,providing scientific evidence for developing functional cosmetics.
文摘In recent years,numer-ous single-atom catalysts(SACs)have been synthesized to activate persulfate(PS)by a non-radical pathway because of its high se-lectivity,and activity for the cata-lyst.Metal-nitrogen-carbon(M-N_(x)-C)has been identified as the key active site in SACs.Although methods for preparing SACs have been extensively reported,a systematic summary of the direct construction of M-N_(x)-C,espe-cially unconventional metal-nitrogen-carbon(UM-N_(x)-C,x≠4),on SACs for PS non-radical activation has still not been reported.The role of the M-N_(x)-C active sites on PS non-radical activation is discussed and methods for the formation of M-N_(x)-C and UM-N_(x)-C active sites in SACs and the effect of catalyst carriers such as carbon nitride(g-C_(3)N_(4)),MOFs,COFs,and other car-bon materials are reviewed.Direct and indirect methods,especially for UM-N_(x)-C active site formation,are also elaborated.Factors affecting the formation of a M-N_(x)-C active site on SACs are also discussed.Prospects for the use of M-N_(x)-C active sites for the non-radical activation of PS by SACs to remove organic contaminants from wastewater are evaluated.
基金supported by Research Grant from China Petroleum and Chemical Corp。
文摘Cu/ZnO-based catalysts are widely employed for methanol synthesis via CO_(2) hydrogenation.The preparation procedure is sensitive to the particle size and interfacial structure,which are considered as potential active centers influencing the rate of both methanol and CO formation.The particle size and the interaction between Cu and the support materials are influenced by the coprecipitation conditions,let alone that the mechanistic divergence remains unclear.In this work,a series of Cu/ZnO/ZrO_(2) catalysts were prepared via co-precipitation at different pH value and systematically characterized.The structure has been correlated with kinetic results to establish the structure-performance relationship.Kinetic analysis demonstrates that methanol synthesis follows a single-site Langmuir-Hinshelwood(L-H)mechanism,i.e.,Cu serves as the active site where CO_(2) and H_(2) competitively adsorb and react to form methanol.In contrast,CO formation proceeds via a dual-site L-H mechanism,where CO_(2) adsorbs onto ZnO and H_(2) onto Cu,with the reaction occurring at the Cu/ZnO interface.Therefore,for the direct formation of methanol,solely reducing the particle size of Cu would not be beneficial.
基金supported by the National Natural Science Foundation of China(62273119).
文摘A cooperative guidance law is proposed in a two-ontwo engagement scenario with large-heading-errors by choosing zero-effort miss distance as a sliding surface,which consists of an attacker,a protector,a defender,and a target,based on fixed-time sliding mode control theory.Based on the nonlinear method of fixed-time sliding mode control,the performance of the cooperative guidance law remains satisfactory even with large-heading-errors scenarios where the linearization-based approaches might be invalid.By virtue of this law,the attacker pursues the target with the assistance of the protector,which can intercept the defender in the engagement scenario.Furthermore,if the attacker is intercepted by the defender,the guidance law of the protector could guarantee that the protector attacks the target.A robust adaptive term is included in the guidance law to deal with the case of the unknown disturbance upper bound of the defender-target team.Finally,the feasibility of the guidance law is verified by nonlinear numerical simulations,and the superiority of it is illustrated by comparing with the linearization guidance law.
文摘Because of an unfortunate mistake by authors,the Project(5227010679)of Foundation item was wrong.The corrected Project is shown as follows:Project(52271073).
基金supported by the National Natural Science Foundation of China(62203222)the Science and Technology Major Project of Jiangsu Province(BG2024041)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX24_0676).
文摘This paper investigates the high-performance control issues of systems affected by time-varying disturbances and measurement noise.Conventionally,active disturbance rejection control(ADRC)is a favorable control strategy to reject unknown disturbances and uncertainties.However,its control performance is limited because standard extended state observer(ESO)struggles to effectively estimate time-varying disturbances.The emergence of high-order ESO(HESO)alleviates the limitation.Unfortunately,it deteriorates the noise suppression capability when the disturbance rejection is enhanced.To tackle this challenge,an improved ADRC with cascade HESO(CHESO)is proposed.A comprehensive theoretical analysis associated with the performance of HESO is given for the first time.The presented analyses provide an intuitive understanding of the performance of HESO.Then,a novel CHESO is developed.The convergence of CHESO is proved via input-to-state stable theory.Extensive frequency domain analyses indicate that CHESO has stronger disturbance rejection and high-frequency noise attenuation performance than ESO and HESO without increasing the observer bandwidth.Comparative simulations conducted on a servo control system validate the effectiveness and preponderance of the proposed method.
文摘为弥补现有开采沉陷预测程序在可视化表达中的缺陷,采用VB和SURFER的Active X Automation技术开发了基于概率积分法的开采沉陷预测分析系统。通过VB语言操纵SURFER内核程序实现开采沉陷的各种移动变形等值线、三维表面图及剖面图制作和数据分析的自动化。以山东某煤矿多工作面、多煤层开采沉陷预计对所建立分析系统进行验证。结果表明,采用VB与SURFER结合用于开采沉陷的预测分析,能够满足工程需要,并且能极大地提高工作效率,减少程序开发的工作量,实现开采沉陷预测分析图件制作的专业化、自动化。
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(JC200903180555A) supported by Shenzhen City Science and Technology Plan, China
文摘A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.
文摘OBJECTIVE Liuwei Dihuang Decoction(LW)-active fraction combination(LW-AFC,consist of 3 fractions polysaccharide,LWB-B;glycoside,LWD-b;oligosaccharide,CA-30)is extracted from LW,it is effective for the treatment of kidney yin deficiency in many animal models.This study evaluated the effects and mechanisms of LW-AFC and the active fractions 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 1h 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 Cort and glutamate,and LW-AFC could inhibit the Cort-induced elevation of Cort 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 Cort 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.
