期刊文献+
共找到208篇文章
< 1 2 11 >
每页显示 20 50 100
Using neural network modeling to improve the detection accuracy of land subsidence due to groundwater withdrawal
1
作者 Ali M.RAJABI Ali EDALAT +1 位作者 Yasaman ABOLGHASEMI Mahdi KHODAPARAST 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2320-2333,共14页
Despite the high efficiency of remote sensing methods for rapid and large-scale detection of subsidence phenomena,this technique has limitations such as atmospheric impact and temporal and spatial decorrelation that a... Despite the high efficiency of remote sensing methods for rapid and large-scale detection of subsidence phenomena,this technique has limitations such as atmospheric impact and temporal and spatial decorrelation that affect the accuracy of the results.This paper proposes a method based on an artificial neural network to improve the results of monitoring land subsidence due to groundwater overexploitation by radar interferometry in the Aliabad plain(Central Iran).In this regard,vertical ground deformations were monitored over 18 months using the Sentinel-1A SAR images.To model the land subsidence by a multilayer perceptron(MLP)artificial neural network,four parameters,including groundwater level,alluvial thickness,elastic modulus,and transmissivity have been applied.The model's generalizability was assessed using data derived for 144 days.According to the results,the neural network estimates the land subsidence at each ground point with an accuracy of 6.8 mm.A comparison between the predicted and actual values indicated a significant agreement.The MLP model can be used to improve the results of subsidence detection in the study area or other areas with similar characteristics. 展开更多
关键词 DINSAR Land subsidence Groundwater withdrawal Aliabad plain Artificial neural network
下载PDF
Large-Scale Carbon Dioxide Storage in Salt Caverns:Evaluation of Operation,Safety,and Potential in China
2
作者 Wei Liu Xiong Zhang +8 位作者 Jifang Wan Chunhe Yang Liangliang Jiang Zhangxin Chen Maria Jose Jurado Xilin Shi Deyi Jiang Wendong Ji Qihang Li 《Engineering》 SCIE EI CAS CSCD 2024年第9期226-246,共21页
Underground salt cavern CO_(2) storage(SCCS)offers the dual benefits of enabling extensive CO_(2) storage and facilitating the utilization of CO_(2) resources while contributing the regulation of the carbon market.Its... Underground salt cavern CO_(2) storage(SCCS)offers the dual benefits of enabling extensive CO_(2) storage and facilitating the utilization of CO_(2) resources while contributing the regulation of the carbon market.Its economic and operational advantages over traditional carbon capture,utilization,and storage(CCUS)projects make SCCS a more cost-effective and flexible option.Despite the widespread use of salt caverns for storing various substances,differences exist between SCCS and traditional salt cavern energy storage in terms of gas-tightness,carbon injection,brine extraction control,long-term carbon storage stability,and site selection criteria.These distinctions stem from the unique phase change characteristics of CO_(2) and the application scenarios of SCCS.Therefore,targeted and forward-looking scientific research on SCCS is imperative.This paper introduces the implementation principles and application scenarios of SCCS,emphasizing its connections with carbon emissions,carbon utilization,and renewable energy peak shaving.It delves into the operational characteristics and economic advantages of SCCS compared with other CCUS methods,and addresses associated scientific challenges.In this paper,we establish a pressure equation for carbon injection and brine extraction,that considers the phase change characteristics of CO_(2),and we analyze the pressure during carbon injection.By comparing the viscosities of CO_(2) and other gases,SCCS’s excellent sealing performance is demonstrated.Building on this,we develop a long-term stability evaluation model and associated indices,which analyze the impact of the injection speed and minimum operating pressure on stability.Field countermeasures to ensure stability are proposed.Site selection criteria for SCCS are established,preliminary salt mine sites suitable for SCCS are identified in China,and an initial estimate of achievable carbon storage scale in China is made at over 51.8-77.7 million tons,utilizing only 20%-30%volume of abandoned salt caverns.This paper addresses key scientific and engineering challenges facing SCCS and determines crucial technical parameters,such as the operating pressure,burial depth,and storage scale,and it offers essential guidance for implementing SCCS projects in China. 展开更多
关键词 Carbon-neutrality Salt cavern Large-scale CO_(2)storage Injection and withdrawal Stability analysis
下载PDF
Hydrodynamic characteristics and particle tracking of 90° lateral intakes at an inclined river slope
3
作者 Wei He Si-yuan Feng +4 位作者 Jian Zhang Hong-wu Tang Yang Xiao Sheng Chen Chun-sheng Liu 《Water Science and Engineering》 EI CAS CSCD 2024年第2期197-208,共12页
Lateral intakes are common in rivers.The pump effciency and sediment deposition are determined by the local hydrodynamic characteristics and mainstream division width.The hydraulic characteristics of lateral withdrawa... Lateral intakes are common in rivers.The pump effciency and sediment deposition are determined by the local hydrodynamic characteristics and mainstream division width.The hydraulic characteristics of lateral withdrawal from inclined river slopes at different intake elevations should be investigated.Meanwhile,the division width exhibits significant vertical non-uniformity at an inclined river slope,which should be clarified.Hence,a three-dimensional(3-D)hydrodynamic and particle-tracking model was developed with the Open Source Field Operation and Manipulation(Open FOAM),and the model was validated with physical model tests for 90°lateral withdrawal from an inclined side bank.The flow fields,withdrawal sources,and division widths were investigated with different intake bottom elevations,withdrawal discharges,and main channel velocities.This study showed that under inclined side bank conditions,water entered the intake at an oblique angle,causing significant 3-D spiral flows in the intake rather than two-dimensional closed recirculation.A lower withdrawal discharge,a lower bottom elevation of the intake,or a higher main channel velocity could further strengthen this phenomenon.The average division width and turbulent kinetic energy were smaller under inclined side bank conditions than under vertical bank conditions.With a low intake bottom elevation,a low withdrawal discharge,or a high main channel velocity,the sources of lateral withdrawal were in similar ranges near the local inclined bank in the vertical direction.Under inclined slope conditions,sediment deposition near the intake entrance could be reduced,compared to that under vertical slope conditions.The results provide hydrodynamic and sediment references for engineering designs for natural rivers with inclined terrains. 展开更多
关键词 Lateral withdrawal Hydrodynamic characteristics Particle tracking Inclined river slope Bottom elevation of intake OPENFOAM
下载PDF
Discussion on Land Use Mode Reform in Coal Opencast Mining
4
作者 Hong ZHANG Lin LIN 《Asian Agricultural Research》 2024年第1期25-28,共4页
The existing land supply mode of opencast mining is"land requisition first,then transfer",which lacks an effective recovery and withdrawal mechanism,and the reclaimed mining land is difficult to withdraw.Acc... The existing land supply mode of opencast mining is"land requisition first,then transfer",which lacks an effective recovery and withdrawal mechanism,and the reclaimed mining land is difficult to withdraw.According to the regular rules of coal opencast mining and the periodic characteristics of land use,this paper puts forward a new mode of temporary land use for coal opencast mining.It is conducive to im-proving the quality and scale of land use and reclamation utilization of opencast coal mining,and is of great significance for exploring and for-mulating reasonable land use policies for mineral resources development projects. 展开更多
关键词 Opencast mine Temporary land use Land requisition RECLAMATION Withdrawal mechanism
下载PDF
A Problem Not to Be Ignored: The Influencing Factors of Mobile Phone Addiction and Its Influence on Sleep Quality
5
作者 Zihan Ji Lian Zhou 《Health》 2024年第5期459-469,共11页
Background and Objective: With the popularity and widespread use of mobile phones, the effects of mobile phone dependence and addiction on individuals’ physical and mental health have attracted more and more attentio... Background and Objective: With the popularity and widespread use of mobile phones, the effects of mobile phone dependence and addiction on individuals’ physical and mental health have attracted more and more attention. The present study aims to analyze the current state of mobile phone addiction and its impact on sleep quality within the population, while also exploring the influence of related factors on sleep quality. Ultimately, this research will provide a scientific foundation for targeted intervention measures and strategies. Methods: A total of 253 permanent residents in Nanjing were randomly selected as study subjects. The Mobile Phone Addiction Index (MPAI) and Pittsburgh Sleep Quality Index (PSQI) were used to evaluate the degree of smartphone addiction and sleep quality of the study subjects. Body mass index (BMI) was measured according to standardized procedures. Independent sample t-test, Chi-square test, rank sum test and multiple linear regression were used to analyze the correlation between mobile phone addiction and sleep quality, and P Results: 117 people (46.2%) were addicted to mobile phones. Chi-square test showed that the rate of mobile phone addiction in drinking group was significantly higher than that in non-drinking group (P P P P P P P P P P Conclusion: Mobile phone addiction may lead to shorter sleep duration and reduce sleep efficiency. The withdrawal of mobile phone addiction may have a negative impact on sleep quality. According to the characteristics of the population, appropriate comprehensive intervention measures should be taken to build an effective evaluation system, so as to reduce the impact of mobile phone addiction and withdrawal problems on sleep and improve sleep quality. 展开更多
关键词 Mobile Phone Addiction Influencing Factors WITHDRAWAL Sleep Quality
下载PDF
中国疫苗供应管理现状及挑战 被引量:1
6
作者 李星辉 李梦颖 +5 位作者 付朝伟 严非 王娜 王伟 阿克忠 王颖 《中国卫生资源》 北大核心 2021年第2期150-152,共3页
目的分析全国31个省(自治区、直辖市)和新疆生产建设兵团(以下简称“兵团”)的疫苗供应管理现状,总结我国疫苗供应管理的经验及面临的挑战,为疫苗供应管理决策提供参考。方法对全国31个省(自治区、直辖市)的省(自治区、直辖市)级疾病预... 目的分析全国31个省(自治区、直辖市)和新疆生产建设兵团(以下简称“兵团”)的疫苗供应管理现状,总结我国疫苗供应管理的经验及面临的挑战,为疫苗供应管理决策提供参考。方法对全国31个省(自治区、直辖市)的省(自治区、直辖市)级疾病预防控制中心和兵团疾病预防控制中心进行机构问卷调查,调查内容为疫苗供应管理情况。结果全国31个省(自治区、直辖市)和兵团均出现过疫苗供应不及时的情况,供应延迟的平均天数普遍较长。疫苗配送的及时性总体良好。相比东中部地区,西部地区更需要采购应急疫苗。结论我国疫苗配送的及时性总体良好,对疫苗需求把控准确。但部分疫苗供应紧张,二类疫苗退出机制有待建立,西部地区在疫苗调动及库存把控方面有较大提升空间。 展开更多
关键词 疫苗vaccine 供应supply 管理management 配送distribution 二类疫苗typeⅡvaccine 退出机制withdrawal mechanism 应急疫苗emergent vaccine
下载PDF
Microstructure optimization of directionally solidified hypereutectic Nb-Si alloy 被引量:2
7
作者 王嘉宜 贾丽娜 +3 位作者 马立敏 原赛男 张晓丽 张虎 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期2874-2881,共8页
Nb-16Si-24Ti-10Cr-2A1-2Hf alloy was directionally solidified with withdrawal rates of 1.2, 6, 18, 36 and 50 mrn/min and then heat treated at 1400, 1450 and 1500℃with withdrawal rate of 50 mm/min for 10 h. The effects... Nb-16Si-24Ti-10Cr-2A1-2Hf alloy was directionally solidified with withdrawal rates of 1.2, 6, 18, 36 and 50 mrn/min and then heat treated at 1400, 1450 and 1500℃with withdrawal rate of 50 mm/min for 10 h. The effects of withdrawal rate and heat treatment temperature on the microstructure were studied. The microstructure of directionally solidified alloy was composed of the primary NbsSi3, Nbss/NbsSi3 eutectic cells and Cr2Nb, which distribute paralleled to the growth direction. The microstructure becomes more refined with the increasing withdrawal rate, accompany with the evolution of eutectic cells morphology. After heat treatment, Nbss phase connects and forms a continuous matrix, and the Cr2Nb phase becomes smaller and distributes more dispersedly. After heat treatment at 1450 ℃ for 10 h, the alloy achieves balance between the optimization of microstructure and alleviation of solute segregation. 展开更多
关键词 Nb-Si alloy directional solidification eutectic withdrawal rate microstructure heat treatment
下载PDF
Recent Progress in Studies of the Variabilities and Mechanisms of the East Asian Monsoon in a Changing Climate 被引量:17
8
作者 Wen CHEN Lin WANG +4 位作者 Juan FENG Zhiping WEN Tiaojiao MA Xiuqun YANG Chenghai WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第9期887-901,共15页
Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community... Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community and is particularly challenging in a changing climate where the global mean temperature has been rising.Recent advances in studies of the variabilities and mechanisms of the EAM are reviewed in this paper,focusing on the interannual to interdecadal time scales.Some new results have been achieved in understanding the behaviors of the EAM,such as the evolution of the East Asian summer monsoon(EASM),including both its onset and withdrawal over the South China Sea,the changes in the northern boundary activity of the EASM,or the transitional climate zone in East Asia,and the cycle of the EASM and the East Asian winter monsoon and their linkages.In addition,understanding of the mechanism of the EAM variability has improved in several aspects,including the impacts of different types of ENSO on the EAM,the impacts from the Indian Ocean and Atlantic Ocean,and the roles of mid-to high-latitude processes.Finally,some scientific issues regarding our understanding of the EAM are proposed for future investigation. 展开更多
关键词 EAST ASIAN summer MONSOON EAST ASIAN winter MONSOON CHANGING CLIMATE MONSOON onset and withdrawal transitional CLIMATE zone different types of ENSO
下载PDF
Androgenic regulation of novel genes in the epididymis 被引量:5
9
作者 Bernard Robaire Shayesta Seenundun +1 位作者 Mahsa Hamzeh Sophie-Anne Lamour 《Asian Journal of Andrology》 SCIE CAS CSCD 2007年第4期545-553,共9页
The epididymis is critically dependent on the presence of the testis. Although several hormones, such as retinoids and progestins, and factors secreted directly into the epididymal lumen, such as androgen binding prot... The epididymis is critically dependent on the presence of the testis. Although several hormones, such as retinoids and progestins, and factors secreted directly into the epididymal lumen, such as androgen binding protein and fibroblast growth factor, might play regulatory roles in epididymal function, testosterone (T) and its metabolites, dihydrotestosterone (DHT) and estradiol (E2), are accepted as the primary regulators of epididymal structure and functions, with the former playing the greater role. To ascertain the molecular action of androgens on the epididymis, three complementary approaches were pursued to monitor changes in gene expression in response to different hormonal milieux. The first was to establish changes in gene expression along the epididymis as androgenic support is withdrawn. The second was to determine the sequence of responses that occur in an androgen deprived tissue upon re-administration of the two metabolites of T, DHT and E2. The third was to study the effects of androgen withdrawal and re-administration on gene expression in immortalized murine caput epididymidal principal cells. Specific responses were observed under each of these conditions, with an expected major difference in the panoply of genes expressed upon hormone withdrawal and re-administration; however, some key common features were the common roles of genes in insulin like growth factor/epidermal growth factor and the relatively minor and specific effects of E2 as compared to DHT. Together, these results provide novel insights into the mechanisms of androgen regulation in epididymal principal cells. (Asian J Androl 2007 July; 9: 545-553) 展开更多
关键词 EPIDIDYMIS cell culture androgen withdrawal DIHYDROTESTOSTERONE ESTRADIOL apoptosis SURVIVIN insulin like growth factor
下载PDF
One-dimensional consolidation of visco-elastic aquitard due to withdrawal of deep-groundwater 被引量:8
10
作者 LIU Jia-cai LEI Guo-gang MEI Guo-xiong 《Journal of Central South University》 SCIE EI CAS 2012年第1期282-286,共5页
One-dimensional consolidation of visco-elastic aquitard due to withdrawal of deep-groundwater was studied.Merchant model was used to simulate visco-elastic characteristic of aquitard.General solutions of the governing... One-dimensional consolidation of visco-elastic aquitard due to withdrawal of deep-groundwater was studied.Merchant model was used to simulate visco-elastic characteristic of aquitard.General solutions of the governing equation were obtained by applying Laplace transform with respect to time,and then the pore-pressure,strain and deformation of the aquitard could be calculated by Laplace inversion.A case was analyzed to validate the correctness of the present method.Finally,some consolidation properties of the problem were analyzed.Comparison of the average degree of consolidation defined by pore pressure with that defined by settlement shows that they are different and the maximum difference is 22.8%.The influences of parameters of Merchant model and the rate of the water level on the consolidation are great.The smaller the viscosity coefficient is,the later the rate of consolidation decreases.The rate of consolidation is decreased with the decrease of the rate of the water level fall.Therefore,the lagged effect of land subsidence should be considered in the actual project. 展开更多
关键词 CONSOLIDATION withdrawal of deep-groundwater visco-elastic characteristic Laplace inversion
下载PDF
Thermal behavior of the HTR-10 under combined PLOFC and ATWS condition initiated by unscrammed control rod withdrawal 被引量:5
11
作者 Feng Gou Yuan Liu +1 位作者 Fu-Bing Chen Yu-Jie Dong 《Nuclear Science and Techniques》 SCIE CAS CSCD 2018年第9期130-138,共9页
Two tests initiated by unscrammed control rod withdrawal were performed on the High Temperature GasCooled Reactor-Test Module(HTR-10) in November 2003 after the reactor achieved its full power, and the test conditions... Two tests initiated by unscrammed control rod withdrawal were performed on the High Temperature GasCooled Reactor-Test Module(HTR-10) in November 2003 after the reactor achieved its full power, and the test conditions represented a typical transient scenario of modular high-temperature reactors(HTRs), called pressurized loss of forced cooling, and anticipated transient without scram.Based on the test parameters, the HTR-10 thermal behaviors under the test conditions were studied with the help of the system analysis code THERMIX. The combination of the test results and the investigation results makes the HTR-10 safety potential better understood. Key phenomena, such as the helium natural circulation and the temperature redistribution in the reactor, were revealed. As the safety feature of most significance, there is a large margin between the maximum fuel temperature and its safety limit in each test. Temperatures of thermocouples in different components were calculated by THERMIX and compared with the test values. The applicability of the code was verified by good agreement obtained from the comparison. 展开更多
关键词 HTR-10 Control ROD WITHDRAWAL ATWS THERMIX
下载PDF
ZD 7288,an HCN channel blocker,attenuates chronic visceral pain in irritable bowel syndrome-like rats 被引量:7
12
作者 Yu Chen Chun Lin +3 位作者 Ying Tang Ai-Qin Chen Cui-Ying Liu Da-Li Lu 《World Journal of Gastroenterology》 SCIE CAS 2014年第8期2091-2097,共7页
AIM: To investigate the effects of ZD 7288, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, on rats with chronic visceral pain.
关键词 Abdominal withdrawal reflex ELECTROMYOGRAPHY Hyperpolarization-activated cyclic nucleotide-gated channel Visceral hypersensitivity ZD 7288 Irritable bowel syndrome
下载PDF
Quality indicators for colonoscopy: Current insights and caveats 被引量:9
13
作者 Hendrikus JM Pullens Peter D Siersema 《World Journal of Gastrointestinal Endoscopy》 CAS 2014年第12期571-583,共13页
Colonoscopy is the diagnostic modality of choice for investigation of symptoms suspected to be related to the colon and for the detection of polyps and colorectal cancer(CRC). Colonoscopy with removal of detected poly... Colonoscopy is the diagnostic modality of choice for investigation of symptoms suspected to be related to the colon and for the detection of polyps and colorectal cancer(CRC). Colonoscopy with removal of detected polyps has been shown to reduce the incidence and mortality of subsequent CRC. In many countries, population screening programs for CRC have been initiated, either by selection of patients for colonoscopy with fecal occult blood testing or by offering colonoscopy directly to average-risk individuals. Several endoscopy societies have formulated quality indicators for colonoscopy. These quality indicators are almost always incorporated as process indicators, rather than outcome measures. This review focuses on the quality indicators bowel preparation, cecal intubation rate, withdrawal time, adenoma detection rate, patient comfort, sedation and complication rate, and discusses the scientific evidence supporting them,as well as their potential shortcomings and issues that need to be addressed. For instance, there is still no clear and generally accepted definition of adequatebowel preparation, no robust scientific evidence is available supporting a cecal intubation rate ≥ 90% and the association between withdrawal time and occurrence of interval cancers has not been clarified. Adenoma detection rate is currently the only quality indicator that has been shown to be associated with interval colorectal cancer, but as an indicator it does not differentiate between subjects with one or more adenoma detected. 展开更多
关键词 COLONOSCOPY Quality indicators Bowel preparation Cecal INTUBATION WITHDRAWAL time ADENOMA detection rate Screening Complication Interval COLORECTAL CANCER Post-colonoscopy COLORECTAL CANCER
下载PDF
The withdrawal of the U.S. from the Paris Agreement and its impact on global climate change governance 被引量:5
14
作者 ZHANG Yong-Xiang CHAO Qing-Chen +1 位作者 ZHENG Qiu-Hong HUANG Lei 《Advances in Climate Change Research》 SCIE CSCD 2017年第4期213-219,共7页
The global community has prepared for the withdrawal of the U.S. from the Paris Agreement since Donald Trump was elected as the president of the U.S. However, Trump's formal declaration of withdrawal still caused ... The global community has prepared for the withdrawal of the U.S. from the Paris Agreement since Donald Trump was elected as the president of the U.S. However, Trump's formal declaration of withdrawal still caused worldwide reaction. Trump will use the withdrawal to build his political reputation and to renegotiate the Paris Agreement despite its negative effects on the political credibility, international relationships, and potential long-term economic growth of the U.S. In general, the withdrawal of the U.S. from the Paris Agreement will not change the development of low-carbon technologies and the transformation trend of the global climate governance regime. However, the long-term goals and international cooperation on climate change will be affected by budget cuts in American climate change research and the cancelation of donations from the multilateral environmental fund of the U.S. If the Paris Agreement is renegotiated, the common but differentiated principle of responsibility of the United Nations Framework Convention on Climate Change will be challenged again. Nevertheless, climate change governance remains a main theme of future sustainable development. Instead of national governments, local governments and non-governmental organizations will develop strategies for technical innovation and emphasize pragmatic cooperation, thus expanding their roles in climate change governance. The capacity building on climate change research and public awareness should be enhanced as a long-term objective of global climate change governance. 展开更多
关键词 U.S. withdraw PARIS AGREEMENT Global climate change GOVERNANCE IMPACT
下载PDF
Corticosteroid-free immunosuppression in liver transplantation: An evidence-based review 被引量:6
15
作者 George Sgourakis Georgia Dedemadi 《World Journal of Gastroenterology》 SCIE CAS 2014年第31期10703-10714,共12页
Thirty-six randomized controlled trials and two metaanalyses were reviewed. With respect to adult patients undergoing first orthotopic liver transplantation(OLT), steroid replacement resulted in fewer cases of overall... Thirty-six randomized controlled trials and two metaanalyses were reviewed. With respect to adult patients undergoing first orthotopic liver transplantation(OLT), steroid replacement resulted in fewer cases of overall acute rejection in the corticosteroid free-immunosuppression arm. Initial steroid administration for two weeks and early tacrolimus monotherapy is a feasible immunosuppression regimen without steroid replacement, although further investigations are needed in view of chronic rejections. No significant differences were noted between the treatment groups in terms of patient and graft survival independently of steroid replacement. Renal insufficiency, de novo hypertension, neurological disorders and infectious complications did not differ significantly among steroid and steroidfree groups. Diabetes mellitus, cholesterol levels and cytomegalovirus infection are more frequent in patients within the steroid group. With respect to diabetes mellitus and hypercholesterolemia, the difference was independent of steroid replacement. In relation to transplanted hepatitis C virus patients, mycophenolate mofetil does not appear to have a significant antiviral effect despite early reports. Male gender of donors and recipients, living donors, cold ischemia times, acute rejection, and early histological recurrence were related to the development of advanced hepatitis. There is sufficient scientific clinical evidence advocating avoidance of the ab initio use of steroids in OLT. 展开更多
关键词 META-ANALYSIS Evidence based Hepatitis C virus recurrence Liver transplantation Steroid withdrawal Orthotopic liver transplantation
下载PDF
Repeated morphine treatment influences operant and spatial learning differentially 被引量:4
16
作者 Mei-Na WANG Zhi-Fang DONG +1 位作者 Jun CAO Lin XU 《Neuroscience Bulletin》 SCIE CAS CSCD 2006年第3期137-143,共7页
Objective To investigate whether repeated morphine exposure or prolonged withdrawal could influence operant and spatial learning differentially. Methods Animals were chronically treated with morphine or subjected to m... Objective To investigate whether repeated morphine exposure or prolonged withdrawal could influence operant and spatial learning differentially. Methods Animals were chronically treated with morphine or subjected to morphine withdrawal. Then, they were subjected to two kinds of learning: operant conditioning and spatial learning. Results The acquisition of both simple appetitive and cued operant learning was impaired after repeated morphine treatment. Withdrawal for 5 weeks alleviated the impairments. Single morphine exposure disrupted the retrieval of operant memory but had no effect on rats after 5-week withdrawal. Contrarily, neither chronic morphine exposure nor 5-week withdrawal influenced spatial learning task of the Morris water maze. Nevertheless, the retrieval of spatial memory was impaired by repeated morphine exposure but not by 5-week withdrawal. Conclusion These observations suggest that repeated morphine exposure can influence different types of learning at different aspects, implicating that the formation of opiate addiction may usurp memory mechanisms differentially. 展开更多
关键词 MORPHINE ADDICTION WITHDRAWAL CONDITIONING spatial learning
下载PDF
Effect of solidification parameters on the microstructures of a single crystal Ni-based superalloy AM3 被引量:4
17
作者 Yu Zhuhuan Liu Lin +3 位作者 Zhao Xinbao Zhang Weiguo Zhang Jun Fu Hengzhi 《China Foundry》 SCIE CAS 2010年第3期217-223,共7页
A single crystal Ni-based superalloy AM3 was processed at withdraw rates of 3.5, 10, 50, 100, 200, and 500 μm·s-1, respectively.The as-cast microstructures and solidification segregation ratio were characterized... A single crystal Ni-based superalloy AM3 was processed at withdraw rates of 3.5, 10, 50, 100, 200, and 500 μm·s-1, respectively.The as-cast microstructures and solidification segregation ratio were characterized with various withdraw rates.The shape and size of carbide microstructures were determined.As expected, the primary and secondary dendrite arm spacings (PDAS and SDAS) decrease with the increase of withdraw rate.The highest volume fraction of eutectic γ/γ' is observed at the 100 μm·s-1 withdraw rate.The volume fraction of eutectic γ/γ' does not appear to be a strong function of the withdraw rate.With increasing withdraw rate, interface morphologies change in the sequence of planar, cellular, and dendrite.There is a general refinement of the microstructure as the withdraw rate increases.EPMA analysis showed that withdraw rate does not have obvious influence on the segregation of elements. 展开更多
关键词 Ni-based superalloy single crystal withdraw rate solidi fi cation PDAS SDAS
下载PDF
Neurotoxicity of intrathecal injections of dexmedetomidine into the rat spinal dorsal horn 被引量:4
18
作者 Jiabao Hou Zhongyuan Xia Xingpeng Xiao Xing Wan Bo Zhao 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第23期1765-1770,共6页
To investigate the neurotoxicity of intrathecal injections of dexmedetomidine,Sprague-Dawley rats were intrathecally injected with dexmedetomidine at doses of 0.75,1.50 and 3.00μg/kg into the spinal dorsal horn.We fo... To investigate the neurotoxicity of intrathecal injections of dexmedetomidine,Sprague-Dawley rats were intrathecally injected with dexmedetomidine at doses of 0.75,1.50 and 3.00μg/kg into the spinal dorsal horn.We found that c-Fos expression in the rat spinal dorsal horn peaked at 7 hours following the 3.00μg/kg dexmedetomidine injection,while the levels of c-Fos expression following 0.75 and 1.50μg/kg dexmedetomidine were similar to those in the spinal dorsal horn of normal rats. At 48 hours following administration,the level of c-Fos expression was similar to normal levels.In addition,the intrathecal injections of dexmedetomidine increased paw withdrawal mechanical thresholds and prolonged thermal tail flick latencies.These results indicate that dexmedetomidine has pronounced antinociceptive effects.However,dexmedetomidine appears to have neurotoxic effects in the spinal cord because it increased c-Fos expression in the spinal dorsal horn within 7 hours following administration. 展开更多
关键词 DEXMEDETOMIDINE drug toxicity spinal cord FOS paw withdrawal mechanical threshold thermal tail flick latency
下载PDF
Effect of solidification rate on MC-type carbide morphology in single crystal Ni-base superalloy AM3 被引量:4
19
作者 余竹焕 刘林 +3 位作者 赵新宝 张卫国 张军 傅恒志 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第10期1835-1840,共6页
In order to study the effect of the withdrawing rate on carbide morphology,MC-type carbide in single crystal superalloy AM3 was systematically investigated with sample growth rates from 3.5 μm/s to 500 μm/s.The carb... In order to study the effect of the withdrawing rate on carbide morphology,MC-type carbide in single crystal superalloy AM3 was systematically investigated with sample growth rates from 3.5 μm/s to 500 μm/s.The carbide morphologies were investigated by scanning electron microscopy(SEM),and the electron probe microanalysis(EPMA) was used to characterize the carbide composition.The results indicate that the solidification rate is the important factor governing MC carbide growth morphology,size and distribution,composition and growth mechanism.With the increase of withdrawing rate,nodular,rod-like,Chinese script types of carbide morphology are observed.For the low withdrawing rate,with the increase of withdrawing rate,the carbide size becomes larger.For the case of dendritic interface,the carbide size becomes smaller with refinement of dendrites as withdrawing rate increases.The volume fraction of carbides increases with the withdrawing rate increasing. 展开更多
关键词 single crystal Ni-base superalloy carbide morphology withdrawing rate
下载PDF
Differences in cocaine-induced place preference persistence, locomotion and social behaviors between C57BL/6J and BALB/cJ mice 被引量:3
20
作者 Jian-Li WANG Bei WANG Wen CHEN 《Zoological Research》 CAS CSCD 北大核心 2014年第5期426-435,共10页
C57BL/6J and BALB/cJ mice display significant differences in sociability and response to drugs, but the phenotypic variability of their susceptibility to cocaine is still not well known. In this study, the differences... C57BL/6J and BALB/cJ mice display significant differences in sociability and response to drugs, but the phenotypic variability of their susceptibility to cocaine is still not well known. In this study, the differences between these two mice strains in the persistence of cocaine-induced conditioned place preference (CPP), as well as the locomotion and social behaviors after the 24-hour withdrawal from a four-day cocaine (20 mg/kg/day) administration were investigated. The results showed that the cocaine-induced CPP persisted over two weeks in C57BL/6J mice, while it diminished within one week among BALB/cJ mice. After 24-hours of cocaine withdrawal, high levels of locomotion as well as low levels of social interaction and aggressive behavior were found in C57BL/6J mice, but no significant changes were found in BALB/cJ mice, indicating that cocaine-induced CPP persistence, locomotion and social behavior are not consistent between these two strains, and that overall C57BL/6J mice are more susceptible to cocaine than BALB/cJ mice at the tested doses. 展开更多
关键词 COCAINE Conditioned place preference Locomotion Social behavior WITHDRAWAL
下载PDF
上一页 1 2 11 下一页 到第
使用帮助 返回顶部