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APPLICATION OF FUZZY OPTIMIZATION MODEL IN ECOLOGICAL SECURITY PRE-WARNING 被引量:13
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作者 WUKai-ya HUShu-heng SUNShi-qun 《Chinese Geographical Science》 SCIE CSCD 2005年第1期29-33,共5页
Ecological security is a vital problem that people all over the world today have to face and solve, and the situation of ecological security is getting more and more severe and has begun to impede heavily the sustaina... Ecological security is a vital problem that people all over the world today have to face and solve, and the situation of ecological security is getting more and more severe and has begun to impede heavily the sustainable development of social economy. Ecological environment pre-warning has become a hotspot for the modern environment science. This paper introduces the theories of ecological security pre-warning and tries to constitute a pre-warning model of ecological security. In terms of pressure-state-response model, the pre-warning guide line of ecological security is constructed while the pre-warning degree judging model of ecological security is established based on fuzzy optimization. As a case, the model is used to assess the present condition pre-warning of the ecological security of Anhui Province. The result is in correspondence with the real condition: the ecological security situations of 8 cities are dangerous and 9 cities are secure. The result shows that this model is scientific and effective for regional ecological security pre-warning. 展开更多
关键词 ecological security pre-warning fuzzy optimization pre-warning model Anhui Province
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Non-destructive testing and pre-warning analysis on the quality of bolt support in deep roadways of mining districts 被引量:13
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作者 Zhang Houquan Miao Xiexing +2 位作者 Zhang Guimin Wu Yu Chen Yanlong 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第6期989-998,共10页
The bolt support quality of coal roadways is one of the important factors for the efficiency and security of coal production. By means of a self-developed technique and equipment of random non-destructive testing, non... The bolt support quality of coal roadways is one of the important factors for the efficiency and security of coal production. By means of a self-developed technique and equipment of random non-destructive testing, non-destructive detection and pre-warning analysis on the quality of bolt support in deep roadways of mining districts were performed in a number of mining areas. The measured data were obtained in the detection instances of abnormal in-situ stress and support invalidation etc. The corresponding relation between axial bolt load variation and roadway surrounding rock deformation and stability was summarized in different mining service stages. Pre-warning technology of roadway surrounding rock stability is proposed based on the detection of axial bolt load. Meanwhile, pre-warning indicators of axial bolt load in different mining service stages are offered and some successful pre-warning cases are also illustrated.The research results show that the change rules of axial bolt load in different mining service stages are quite similar in different mining areas. The change of axial bolt load is in accord with the adjustment of surrounding rock stress, which can consequently reflect the deformation and stability state of roadway surrounding rock. Through the detection of axial bolt load in different sections of roadways, the status of real-time bolt support quality can be reflected; meanwhile, the rationality of bolt support design can be evaluated which provides reference for bolting parameters optimization. 展开更多
关键词 Deep roadways BOLT support QUALITY RANDOM NONDESTRUCTIVE testing SURROUNDING ROCK stability Prediction and pre-warning
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High-rise building fire pre-warning model based on the support vector regression 被引量:1
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作者 张立宁 张奇 安晶 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期285-290,共6页
Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning fo... Aiming at reducing the deficiency of the traditional fire pre-warning algorithms and the intelligent fire pre-warning algorithms such as artificial neural network,and then to improve the accuracy of fire prewarning for high-rise buildings,a composite fire pre-warning controller is designed according to the characteristic( nonlinear,less historical data,many influence factors),also a high-rise building fire pre-warning model is set up based on the support vector regression( SV R). Then the wood fire standard history data is applied to make empirical analysis. The research results can provide a reliable decision support framework for high-rise building fire pre-warning. 展开更多
关键词 high-rise buildings fire composite fire pre-warning systemdesign the support vector regression pre-warning model
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Pre-warning information dissemination models of different media under emergencies
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作者 Anying Chen Haoran Zhu +1 位作者 Xiaoyong Ni Guofeng Su 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第9期343-352,共10页
Pre-warning plays an important role in emergency handling, especially in urban areas with high population density like Beijing. Knowing the information dissemination mechanisms clearly could help us reduce losses and ... Pre-warning plays an important role in emergency handling, especially in urban areas with high population density like Beijing. Knowing the information dissemination mechanisms clearly could help us reduce losses and ensure the safety of human beings during emergencies. In this paper, we propose the models of pre-warning information dissemination via five classical media based on actual pre-warning issue processes, including television, radio, short message service (SMS), electronic screens, and online social networks. The population coverage ability and dissemination efficiency at different issue time of these five issue channels are analyzed by simulation methods, and their advantages and disadvantages are compared by radar graphs. Results show that SMS is the most appropriate way to issue long-term pre-warning for its large population coverage, but it is not suitable for issuing urgent warnings to large population because of the limitation of telecom company's issue ability. TV shows the best performance to combine the dissemination speed and range, and the performance of radio and electronic screens are not as satisfactory as the others. In addition, online social networks might become one of the most promising communication method for its potential in further diffusion. These models and results could help us make pre-warning issue plans and provide guidance for future construction of information diffusion systems, thus reducing injuries, deaths, and other losses under different emergencies. 展开更多
关键词 information dissemination emergency pre-warning MEDIA
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Mechanical behavior and failure mechanisms of rock bolts subjected to static-dynamic loads 被引量:1
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作者 Hongpu Kang Guiyang Yuan +4 位作者 Linpo Si Fuqiang Gao Jinfu Lou Jinghe Yang Shuangyong Dong 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期281-288,共8页
This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load fram... This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load frame to simulate various failure scenarios,pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined loads.The experimental results denote that with increased impact energy,maximum and average impact loads on rock bolts escalate significantly under pretension,initiating plastic deformation beyond a certain threshold.Despite minor reductions in the yield load due to impactinduced damage,pretension aids in constraining post-impact deformation rate and fluctuation degree of rock bolts.Moreover,impact-induced plastic deformation causes internal microstructure dislocation,fortifying the stiffness of the rock bolt support system.The magnitude of this fortification is directly related to the plastic deformation induced by the impact.These findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation,emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency. 展开更多
关键词 Rock bolt PRETENSION static and dynamic load IMPACT
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Gas concentration pre-warning system based on fuzzy structured element
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作者 任志玲 于群 《Journal of Coal Science & Engineering(China)》 2008年第4期581-584,共4页
In order to accurately test gas concentration and effectively pre-waming when the gas concentration over-limited on work face, used the high-performance and low prices SCM and the low-cost and high transfer efficiency... In order to accurately test gas concentration and effectively pre-waming when the gas concentration over-limited on work face, used the high-performance and low prices SCM and the low-cost and high transfer efficiency bluetooth technology to forecast the gas concentration in real time. The data tested by SCM, then got the corresponding mathematical model of the data. Put forward the idea of using fuzzy structured element theory to dynamic forecast the gas concentration, analyzed the features in abnormal-effusing on work face and judge whether there was the possibility of abnormal gas-effusion. Simulation results show that mathematical model of this system about gas concentration is correct. This system changes coal mine monitoring system's traditional way of after-alarming into early-warning, and thus enhances its feasibility. 展开更多
关键词 gas concentration pre-warning structured element MONITORING
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Current Situations and Future Development Trend of Farmland Pre-warning Researches in China
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作者 Yongqi JIANG Xiangli WU 《Asian Agricultural Research》 2014年第4期45-49,53,共6页
This paper summarized theory discussion,main research methods,contents,empirical and engineering researches of farmland prewarning in China.It stated that future researches of farmland pre-warning in China will focus ... This paper summarized theory discussion,main research methods,contents,empirical and engineering researches of farmland prewarning in China.It stated that future researches of farmland pre-warning in China will focus on deepening application of farmland security prewarning models,revealing mechanism of changes in different farmland resources,establishing pre-warning models suitable for research areas,accurate evaluation and prediction of farmland security,and exploring establishing and improving farmland security monitoring system and operating mechanism of all levels. 展开更多
关键词 FARMLAND pre-warning SECURITY ASSESSMENT and predi
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Energy mechanism of bolt supporting effect to fissured rock under static and dynamic loads in deep coal mines 被引量:1
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作者 Deyuan Fan Xuesheng Liu +2 位作者 Yunliang Tan Xuebin Li Shenglong Yang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期371-384,共14页
The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal mines.In this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured... The stability control of fissured rock is difficult,especially under static and dynamic loads in deep coal mines.In this paper,the dynamic mechanical properties,strain rate evolution and energy dissipation of fissured and anchored rocks were respectively obtained by SHPB tests.It was found that bolt can provide supporting efficiency-improving effect for fissured rock against dynamic disturbance,and this effect increased quadratically with decrease in anchoring angles.Then,the energy dissipation mechanism of anchored rock was obtained by slipping model.Furthermore,bolt energy-absorbing mechanism by instantaneous tensile-shear deformation was expressed based on material mechanics,which was the larger the anchoring angle,the smaller the energy absorption,and the less the contribution to supporting efficiency improvement.On this basis,the functional relationship between energy dissipation of anchored rock and energy absorption of bolt was established.Taking the coal-gangue separation system of Longgu coal mine as an example,the optimal anchoring angle can be determined as 57.5°–67.5°.Field monitoring showed fissured rock with the optimal anchoring angle,can not only effectively control the deformation,but also fully exert the energy-absorbing and efficiency-improving effect of bolt itself.This study provides guidance to the stability control and supporting design for deep engineering under the same or similar conditions. 展开更多
关键词 static and dynamic loads Anchored rock Energy absorption Anchoring angle Engineering verification
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Influence of static cartoons combined with dynamic virtual environments on preoperative anxiety of preschool-aged children undergoing surgery 被引量:1
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作者 Ya-Lin Zhang Qi-Ying Zhou +3 位作者 Peng Zhang Lin-Feng Huang Li Jin Zhi-Guo Zhou 《World Journal of Clinical Cases》 SCIE 2024年第22期4947-4955,共9页
BACKGROUND Preschoolers become anxious when they are about to undergo anesthesia and surgery,warranting the development of more appropriate and effective interventions.AIM To explore the effect of static cartoons comb... BACKGROUND Preschoolers become anxious when they are about to undergo anesthesia and surgery,warranting the development of more appropriate and effective interventions.AIM To explore the effect of static cartoons combined with dynamic virtual environments on preoperative anxiety and anesthesia induction compliance in preschool-aged children undergoing surgery.METHODS One hundred and sixteen preschool-aged children were selected and assigned to the drug(n=37),intervention(n=40),and control(n=39)groups.All the children received routine preoperative checkups and nursing before being transferred to the preoperative preparation room on the day of the operation.The drug group received 0.5 mg/kg midazolam and the intervention group treatment consisting of static cartoons combined with dynamic virtual environments.The control group received no intervention.The modified Yale Preoperative Anxiety Scale was used to evaluate the children’s anxiety level on the day before surgery(T0),before leaving the preoperative preparation room(T1),when entering the operating room(T2),and at anesthesia induction(T3).Compliance during anesthesia induction(T3)was evaluated using the Induction Compliance Checklist(ICC).Changes in mean arterial pressure(MAP),heart rate(HR),and respiratory rate(RR)were also recorded at each time point.RESULTS The anxiety scores of the three groups increased variously at T1 and T2.At T3,both the drug and intervention groups had similar anxiety scores,both of which were lower than those in the control group.At T1 and T2,MAP,HR,and RR of the three groups increased.The drug and control groups had significantly higher MAP and RR than the intervention group at T2.At T3,the MAP,HR,and RR of the drug group decreased and were significantly lower than those in the control group but were comparable to those in the intervention group.Both the drug and intervention groups had similar ICC scores and duration of anesthesia induction(T3),both of which were higher than those of the control group.CONCLUSION Combining static cartoons with dynamic virtual environments as effective as medication,specifically midazolam,in reducing preoperative anxiety and fear in preschool-aged children.This approach also improve their compliance during anesthesia induction and helped maintain their stable vital signs. 展开更多
关键词 PRESCHOOL Children static cartoons combined with dynamic virtual environments Preoperative anxiety COMPLIANCE Anesthesia induction
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A Vehicle Behavioral Analysis of the Signal Pre-warning Information Provided to the Driver
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作者 Toshiyuki Nakamura Tatsuki Nakayama +1 位作者 Nobuhiro Uno Keiichi Yamamura 《Journal of Traffic and Transportation Engineering》 2016年第1期11-17,共7页
In this study, we analyze whether there is a change in driver actions because of voice navigation information provided by utilizing ITS (intelligent transport systems). Specifically, when a vehicle approaches a sign... In this study, we analyze whether there is a change in driver actions because of voice navigation information provided by utilizing ITS (intelligent transport systems). Specifically, when a vehicle approaches a signalized intersection, the driver is provided with the voice navigation information that the signal light will shortly change red. We focus on what is effective when the voice navigation information is provided. Even if the timing of the provision of voice information is delayed, we have evaluated whether the vehicle is able to stop safely. From the results of the analysis, by providing voice navigation information, we know that a vehicle will stop safely at a signalized intersection. Even if the information provided by voice navigation has been delayed, it could be shown to be safe compared with the case where no information was provided. 展开更多
关键词 Driving simulator signal pre-warning information vehicle behaviour.
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Generalized polynomial chaos expansion by reanalysis using static condensation based on substructuring
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作者 D.LEE S.CHANG J.LEE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第5期819-836,共18页
This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a gen... This paper presents a new computational method for forward uncertainty quantification(UQ)analyses on large-scale structural systems in the presence of arbitrary and dependent random inputs.The method consists of a generalized polynomial chaos expansion(GPCE)for statistical moment and reliability analyses associated with the stochastic output and a static reanalysis method to generate the input-output data set.In the reanalysis,we employ substructuring for a structure to isolate its local regions that vary due to random inputs.This allows for avoiding repeated computations of invariant substructures while generating the input-output data set.Combining substructuring with static condensation further improves the computational efficiency of the reanalysis without losing accuracy.Consequently,the GPCE with the static reanalysis method can achieve significant computational saving,thus mitigating the curse of dimensionality to some degree for UQ under high-dimensional inputs.The numerical results obtained from a simple structure indicate that the proposed method for UQ produces accurate solutions more efficiently than the GPCE using full finite element analyses(FEAs).We also demonstrate the efficiency and scalability of the proposed method by executing UQ for a large-scale wing-box structure under ten-dimensional(all-dependent)random inputs. 展开更多
关键词 forward uncertainty quantification(UQ) generalized polynomial chaos expansion(GPCE) static reanalysis method static condensation SUBSTRUCTURING
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Static Stretching Combined with Conscious Slower Breathing May Increase Parasympathetic Activity and Reduce Stress in Adult Women
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作者 Mami Sakurai Yasushi Ikarashi +3 位作者 Masahiro Tabuchi Ailing Hu Takuji Yamaguchi Hiroyuki Kobayashi 《Health》 2024年第3期242-256,共15页
Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields t... Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields to not only increase muscle flexibility but also reduce stress. Additionally, conscious slower breathing (CSB) predominates parasympathetic activity, causing a relaxing effect. These results indicate that combining SST and CSB may be more useful in reducing stress. However, to the best of our knowledge, the effect of this combination remains unclear. Objective: This study aimed to elucidate the effects of the combination of SST and CSB on autonomic activity and stress in adult women. Methods: Eleven healthy Japanese adult female participants performed SST with nonconscious natural breathing for 20 min. The same participants performed SST in combination with CSB (2 s inspiratory and 4 s expiratory) for 20 min on another day. Salivary cortisol and chromogranin A levels were measured before and after stretching as stress markers of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. The coefficient of variation of the R-R interval (CVR-R) and high-frequency component (HF), which reflect parasympathetic nerve activity, and heart rate and low-frequency component (LF)/HF ratio, which reflect sympathetic nerve activity, were measured before, during, and after stretching. Results: SST decreased cortisol levels but with no significant changes in chromogranin A, heart rate, CVR-R, HF, or LF/HF ratio. The combination of SST and CSB increased CVR-R and HF levels in addition to decreasing cortisol levels but with no significant changes in chromogranin A, heart rate, or LF/HF levels. Conclusion: These results indicate that the combination of SST and CSB may increase parasympathetic activity and reduce stress. However, future randomized controlled trials with larger sample sizes should support this conclusion. 展开更多
关键词 static Stretching Conscious Slower Breathing Autonomic Activity Heart Rate Variability STRESS
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CFD-PBM coupled modeling of the liquid-liquid dispersion characteristics and structure optimization for Kenics static mixer
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作者 Junhai Deng Shilin Lan +4 位作者 Juchang Wu Shenghua Du Weidong Liu Luchang Han Yefeng Zhou 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第6期173-188,共16页
Kenics static mixers(KSM)are extensively used in industrial mixing-reaction processes by virtue of high mixing efficiency,low power homogenization and easy continuous production.Resolving liquid droplet size and its d... Kenics static mixers(KSM)are extensively used in industrial mixing-reaction processes by virtue of high mixing efficiency,low power homogenization and easy continuous production.Resolving liquid droplet size and its distribution and thus revealing the dispersion characteristics are of great significance for structural optimization and process intensification in the KSM.In this work,a computational fluid dynamics-population balance model(CFD-PBM)coupled method is employed to systematically investigate the effects of operating conditions and structural parameters of KSM on droplet size and its distribution,to further reveal the liquid-liquid dispersion characteristics.Results indicate that higher Reynolds numbers or higher dispersed phase volume fractions increase energy dissipation,reducing Sauter mean diameter(SMD)of dispersed phase droplets and with a shift in droplet size distribution(DSD)towards smaller size.Smaller aspect ratios,greater blade twist and assembly angles amplify shear rate,leading to smaller droplet size and a narrower DSD in the smaller range.The degree of impact exerted by the aspect ratio is notably greater.Notably,mixing elements with different spin enhance shear and stretching efficiency.Compared to the same spin,SMD becomes 3.7-5.8 times smaller in the smaller size range with a significantly narrower distribution.Taking into account the pressure drop and efficiency in a comprehensive manner,optimized structural parameters for the mixing element encompass an aspect ratio of 1-1.5,a blade twist angle of 180°,an assembly angle of 90°,and interlaced assembly of adjacent elements with different spin.This work provides vital theoretical underpinning and future reference for enhancing KSM performance. 展开更多
关键词 CFD Population balance Liquid-liquid dispersion Kenics static mixer
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Dynamic characteristics of coal specimens with varying static preloading levels under low-frequency disturbance load
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作者 WEN Xiao-ze FENG Guo-rui +5 位作者 GUO Jun YU Lu-yang QIAN Rui-peng ZHANG Jie ZHANG Peng-fei FENG Wen-ming 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2644-2657,共14页
The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency di... The mechanical properties of residual coal pillars under the influence of upward mining disturbances significantly affect the safety of residual mining activities on working faces.This study conducted low-frequency disturbance dynamic uniaxial compression tests on coal specimens using a self-developed dynamic-static load coupling electro-hydraulic servo system,and studied the strength evolutions,surface deformations,acoustic emission(AE)characteristic parameters,and the failure modes of coal specimens with different static preloading levels were studied.The disturbance damage is positively correlated with the coal specimen static preload level.Specifically,the cumulative AE count rates of the initial accelerated damage stage for the coal specimens with static preloading level of 60%and 70%of the uniaxial compressive strength(UCS)were 2.66 and 3.19 times that of the 50%UCS specimens,respectively.Macroscopically,this behaviour manifested as a decrease in the compressive strength,and the mean strengths of the disturbance-damaged coal specimens with 60%and 70%of UCS static preloading decreased by 8.53%and 9.32%,respectively,compared to those of the specimens under pure static loading.The crack sources,such as the primary fissures,strongly control the dynamic response of the coal specimen.The difference between the dynamic responses of the coal specimens and that of dense rocks is significant. 展开更多
关键词 low-frequency disturbance dynamic response coal specimens static preloading level
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Acetaminophen overdose-induced acute liver injury can be alleviated by static magnetic field
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作者 Han-Xiao Chen Xin-Yu Wang +11 位作者 Biao Yu Chuan-Lin Feng Guo-Feng Cheng Lei Zhang Jun-Jun Wang Ying Wang Ruo-Wen Guo Xin-Miao Ji Wen-Jing Xie Wei-Li Chen Chao Song Xin Zhang 《Zoological Research》 SCIE CSCD 2024年第3期478-490,共13页
Acetaminophen(APAP),the most frequently used mild analgesic and antipyretic drug worldwide,is implicated in causing 46%of all acute liver failures in the USA and between 40%and 70%in Europe.The predominant pharmacolog... Acetaminophen(APAP),the most frequently used mild analgesic and antipyretic drug worldwide,is implicated in causing 46%of all acute liver failures in the USA and between 40%and 70%in Europe.The predominant pharmacological intervention approved for mitigating such overdose is the antioxidant N-acetylcysteine(NAC);however,its efficacy is limited in cases of advanced liver injury or when administered at a late stage.In the current study,we discovered that treatment with a moderate intensity static magnetic field(SMF)notably reduced the mortality rate in mice subjected to high-dose APAP from 40%to 0%,proving effective at both the initial liver injury stage and the subsequent recovery stage.During the early phase of liver injury,SMF markedly reduced APAPinduced oxidative stress,free radicals,and liver damage,resulting in a reduction in multiple oxidative stress markers and an increase in the antioxidant glutathione(GSH).During the later stage of liver recovery,application of vertically downward SMF increased DNA synthesis and hepatocyte proliferation.Moreover,the combination of NAC and SMF significantly mitigated liver damage induced by high-dose APAP and increased liver recovery,even 24 h post overdose,when the effectiveness of NAC alone substantially declines.Overall,this study provides a noninvasive non-pharmaceutical tool that offers dual benefits in the injury and repair stages following APAP overdose.Of note,this tool can work as an alternative to or in combination with NAC to prevent or minimize liver damage induced by APAP,and potentially other toxic overdoses. 展开更多
关键词 ACETAMINOPHEN Acute liver injury static magnetic fields Oxidative stress DNA synthesis
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The Static Stability Region of an Integrated Electricity-Gas System Considering Voltage and Gas Pressure
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作者 Yunfei Mu Zhibin Liu +5 位作者 Xiangwei Guo Hongjie Jia Kai Hou Xiaodan Yu Bofeng Luo Hairun Li 《Engineering》 SCIE EI CAS CSCD 2024年第5期132-145,共14页
In an integrated electricity-gas system(IEGS),load fluctuations affect not only the voltage in the power system but also the gas pressure in the natural gas system.The static voltage stability region(SVSR)method is a ... In an integrated electricity-gas system(IEGS),load fluctuations affect not only the voltage in the power system but also the gas pressure in the natural gas system.The static voltage stability region(SVSR)method is a tool for analyzing the overall static voltage stability in a power system.However,in an IEGS,the SVSR boundary may be overly optimistic because the gas pressure may collapse before the voltage collapses.Thus,the SVSR method cannot be directly applied to an IEGS.In this paper,the concept of the SVSR is extended to the IEGS-static stability region(SSR)while considering voltage and gas pressure.First,criteria for static gas pressure stability in a natural gas system are proposed,based on the static voltage stability criteria in a power system.Then,the IEGS-SSR is defined as a set of active power injections that satisfies multi-energy flow(MEF)equations and static voltage and gas pressure stability constraints in the active power injection space of natural gas-fired generator units(NGUs).To determine the IEGSSSR,a continuation MEF(CMEF)method is employed to trace the boundary point in one specific NGU scheduling direction.A multidimensional hyperplane sampling method is also proposed to sample the NGU scheduling directions evenly.The obtained boundary points are further used to form the IEGSSSR in three-dimensional(3D)space via a Delaunay triangulation hypersurface fitting method.Finally,the numerical results of typical case studies are presented to demonstrate that the proposed method can effectively form the IEGS-SSR,providing a tool for IEGS online monitoring and dispatching. 展开更多
关键词 Integrated electricity-gas system static stability region Continuation multi-energy flow Multidimensional hyperplane sampling
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Data from Twenty-Three FRB’s Confirm the Universe Is Static and Not Expanding
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作者 Lyndon Errol Ashmore 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第3期1152-1177,共26页
Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This ... Fast Radio Bursts from far away galaxies have travelled through the IGM and provide a tool to study its composition. Presently there are 23 FRB’s whose host galaxies have been identified and the redshift found. This gives us the opportunity to test Dispersion Measure versus redshift predictions made by two models. The Macquart relation for an expanding Universe and the New Tired Light relationship in a static universe. In New Tired Light, redshifts are produced when a photon is absorbed and re-emitted by the electrons in the IGM which recoil on both occasions. Some of the energy of the photon has been transferred to the kinetic energy of the recoiling electron. The photon has less energy, a lower frequency and a longer wavelength. It has been redshifted. Since dispersion is due to an interaction between radio signals and these same electrons one would expect a direct relationship between DM and redshift in the New Tired light model. The relation is DM=(mec/2hre)ln(1+z)and contains no adjustable parameters—just a combination of universal constants related to the electron and photon. Notice that the relation is independent of the electron number density ne since a change in ne affects both the DM and redshift equally. A graph of DM versus ln(1 + z) will be a straight line of gradient (mec/2hre)and, using SI units, substituting for the constants gives 7.318 × 1025 m−2. Using the data from the 23 well localized FRB’s, with the weighting of the DM’s for expansion removed (so that the data corresponds to a static universe), a graph of DM versus ln(1 + z) has a gradient of 6.7 × 1025 m−2—9% below the predicted (mec/2hre). The Macquart relation involves highly processed data and adjustable parameters to allow for “dark energy” and “dark matter” (neither of which has yet been found) and can be reduced to DM = 850z (in units of pc∙cm−3). Using the data from this set of localized FRB’s gives a trendline with gradient 1.10 × 103 pc∙cm−3—almost 30% higher than that predicted in an expanding universe model. The FRB data clearly comes down in favour of a static universe rather than an expanding one. Combining the DM-z relationship for the 23 well localized FRB’s, with the Hubble diagram, drawn using the NED-D compilation of redshift independent extragalactic distances, produces a value of “ne” the mean electron number density of the IGM, of ne=0.48 m−3close to the value ne=0.5 m−3, long since predicted by NTL. 展开更多
关键词 REDSHIFT Dispersion Measure Fast Radio Bursts FRB’s Tired Light static Universe IGM
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Static and Thermal Analysis of Aluminium (413,390,384 and 332) Piston Using Finite Element Method
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作者 Offei David Inusah Jacob Kwaku Nkrumah Vincent Akolbire Atindana 《Modeling and Numerical Simulation of Material Science》 2024年第1期1-38,共38页
The main objective of this research was to examine the suitability of aluminium alloy to design a piston of an internal combustion engine for improvement in weight and cost reduction. The piston was modelled using Aut... The main objective of this research was to examine the suitability of aluminium alloy to design a piston of an internal combustion engine for improvement in weight and cost reduction. The piston was modelled using Autodesk Inventor 2017 software. The modelled piston was then imported into Ansys for further analysis. Static structural and thermal analysis were carried out on the pistons of the four different materials namely: Al 413 alloy, Al 384 alloy, Al 390 alloy and Al332 alloy to determine the total deformation, equivalent Von Mises stress, maximum shear stress, and the safety factor. The results of the study revealed that, aluminium 332 alloy piston deformed less compared to the deformations of aluminium 390 alloy piston, aluminium 384 alloy piston and aluminium 413 alloy piston. The induced Von Mises stresses in the pistons of the four different materials were found to be far lower than the yield strengths of all the materials. Hence, all the selected materials including the implementing material have equal properties to withstand the maximum gas load. All the selected materials were observed to have high thermal conductivity enough to be able to withstand the operating temperature in the engine cylinders. 展开更多
关键词 Von Mise stress Total deformation Aluminium alloy Thermal analysis. PISTON static structural Heat fux
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Mechanical behavior of 2G NPR bolt anchored rock samples under static disturbance loading
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作者 WANG Jiong JIANG Jian +4 位作者 WANG Siyu CHANG Yiwen LIU Peng HE Manchao CHENG Shuang 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2494-2516,共23页
The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering hazards.The implementation of NPR(negative Poisson's ratio)bolts are capable of controlling lar... The deep mining of coal resources is accompanied by severe environmental challenges and various potential engineering hazards.The implementation of NPR(negative Poisson's ratio)bolts are capable of controlling large deformations in the surrounding rock effectively.This paper focuses on studying the mechanical properties of the NPR bolt under static disturbance load.The deep nonlinear mechanical experimental system was used to study the mechanical behavior of rock samples with different anchored types(unanchored/PR anchored/2G NPR anchored)under static disturbance load.The whole process of rock samples was taken by high-speed camera to obtain the real-time failure characteristics under static disturbance load.At the same time,the acoustic emission signal was collected to obtain the key characteristic parameters of acoustic emission such as acoustic emission count,energy,and frequency.The deformation at the failure of the samples was calculated and analyzed by digital speckle software.The findings indicate that the failure mode of rock is influenced by different types of anchoring.The peak failure strength of 2G NPR bolt anchored rock samples exhibits an increase of 6.5%when compared to the unanchored rock samples.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 62.16%and 62.90%,respectively.The maximum deformation of bearing capacity exhibits an increase of 59.27%,while the failure time demonstrates a delay of 42.86%.The peak failure strength of the 2G NPR bolt anchored ones under static disturbance load exhibits an increase of 5.94%when compared to the rock anchored by PR(Poisson's ratio)bolt.The cumulative count and cumulative energy of acoustic emission exhibit a decrease of 47.16%and 43.86%,respectively.The maximum deformation of the bearing capacity exhibits an increase of 50.43%,and the failure time demonstrates a delay of 32%.After anchoring by 2G NPR bolt,anchoring support effectively reduces the risk of damage caused by static disturbance load.These results demonstrate that the support effect of 2G NPR bolt materials surpasses that of PR bolt. 展开更多
关键词 Anchored rock samples static disturbance load Acoustic emission characteristics Digital speckle Negative Poisson's ratio
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Novel Static Security and Stability Control of Power Systems Based on Artificial Emotional Lazy Q-Learning
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作者 Tao Bao Xiyuan Ma +3 位作者 Zhuohuan Li Duotong Yang Pengyu Wang Changcheng Zhou 《Energy Engineering》 EI 2024年第6期1713-1737,共25页
The stability problem of power grids has become increasingly serious in recent years as the size of novel power systems increases.In order to improve and ensure the stable operation of the novel power system,this stud... The stability problem of power grids has become increasingly serious in recent years as the size of novel power systems increases.In order to improve and ensure the stable operation of the novel power system,this study proposes an artificial emotional lazy Q-learning method,which combines artificial emotion,lazy learning,and reinforcement learning for static security and stability analysis of power systems.Moreover,this study compares the analysis results of the proposed method with those of the small disturbance method for a stand-alone power system and verifies that the proposed lazy Q-learning method is able to effectively screen useful data for learning,and improve the static security stability of the new type of power system more effectively than the traditional proportional-integral-differential control and Q-learning methods. 展开更多
关键词 Artificial sentiment static secure stable analysis Q-LEARNING lazy learning data filtering
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