期刊文献+
共找到806篇文章
< 1 2 41 >
每页显示 20 50 100
The Effect of Oxygen Partial Pressure during Active Layer Deposition on Bias Stability of a-InGaZnO TFTs 被引量:2
1
作者 黄晓明 武辰飞 +3 位作者 陆海 任芳芳 朱洪波 王永进 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期171-174,共4页
The effect of oxygen partial pressure (Po2) during the channel layer deposition on bias stability of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) is investigated. As Po2 increases fr... The effect of oxygen partial pressure (Po2) during the channel layer deposition on bias stability of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) is investigated. As Po2 increases from 10% to 30%, it is found that the device shows enhanced bias stress stability with significantly reduced threshold voltage drift under positive gate bias stress. Based on the x-ray photoelectron spectroscopy measurement, the concentration of oxygen vacancies (Or) within the a-IGZO layer is suppressed by increasing Po2. Meanwhile, the low-frequency noise analysis indicates that the average trap density near the channel/dielectric interface continuously drops with increasing Po2. Therefore, the improved interface quality with increasing Po2 during the channel layer deposition can be attributed to the reduction of interface Ov-related defects, which agrees with the enhanced bias stress stability of the a-IGZO TFTs. 展开更多
关键词 TFT The effect of Oxygen partial Pressure during Active Layer Deposition on Bias Stability of a-InGaZnO TFTs
原文传递
Analysis of Partial Volume Effects on Accurate Measurement of the Hippocampus Volume
2
作者 Maryam Hajiesmaeili Jamshid Dehmeshki Tim Ellis 《Journal of Electronic Science and Technology》 CAS 2014年第2期182-186,共5页
Hippocampal volume loss is an important biomarker in distinguishing subjects with Alzheimer's disease (AD) and its measurement in magnetic resonance images (MRI) is influenced by partial volume effects (PVE). T... Hippocampal volume loss is an important biomarker in distinguishing subjects with Alzheimer's disease (AD) and its measurement in magnetic resonance images (MRI) is influenced by partial volume effects (PVE). This paper describes a post-processing approach to quantify PVE for correction of the hippocampal volume by using a spatial fuzzyC-means (SFCM) method. The algorithm is evaluated on a dataset of 20 T1-weighted MRI scans sampled at two different resolutions. The corrected volumes for left and right hippocampus (HC) which are 23% and 18% for the low resolution and 6% and 5% for the high resolution datasets, respectively are lower than hippocampal volume results from manual segmentation. Results show the importance of applying this technique in AD detection with low resolution datasets. 展开更多
关键词 HIPPOCAMPUS magnetic resonance images partial volume effects spatial fuzzy C-means
暂未订购
Effect of salt solutions on chain structure of partially hydrolyzed polyacrylamide 被引量:2
3
作者 张青 周吉生 +2 位作者 翟永爱 刘凤岐 高歌 《Journal of Central South University》 SCIE EI CAS 2008年第S1期80-83,共4页
The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction b... The effect of salt solutions(NaCl,Na2SO4 and CaCl2) on the conformational properties of partially hydrolyzed polyacrylamide(HPAM) was investigated by using static laser light scattering(SLLS).The special interaction between CaCl2 solution and HPAM was also researched.Experimental results show that the chain structure of HPAM is interrelated with the charge density,the kind and the concentration of salt solutions.The mean-square radius of gyration(Rz) and the second virial coefficient(A2) of HPAM decrease with increasing concentration of salt solutions,and the salt effect tends towards the maximum when the concentration of salt solution is increased to some amount. 展开更多
关键词 partialLY hydrolyzed polyacrylamide(HPAM) SALT effect chain structure static laser light scattering(SLLS)
在线阅读 下载PDF
Effects of terlipressin versus splenectomy on liver regeneration after partial hepatectomy in rats: What we know so far? 被引量:6
4
作者 antonios athanasiou eleftherios spartalis +4 位作者 mairead hennessy michael spartalis demetrios moris christos damaskos emmanouil pikoulis 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2018年第1期91-92,共2页
To the editor:We read with great interest the article entitled "Comparative study of the effects of terlipressin versus splenectomy on liver regeneration after partial hepatectomy in rats" by Ulmer et al.[1]... To the editor:We read with great interest the article entitled "Comparative study of the effects of terlipressin versus splenectomy on liver regeneration after partial hepatectomy in rats" by Ulmer et al.[1].The aim of this study was to analyse the impact of terlipressin ver- 展开更多
关键词 effects of terlipressin versus splenectomy on liver regeneration after partial hepatectomy in rats What we know so far
暂未订购
Partial Volume Effect on MR Elastography
5
作者 Daiki Ito Tomokazu Numano +3 位作者 Kazuyuki Mizuhara Toshikatsu Washio Masaki Misawa Naotaka Nitta 《Open Journal of Medical Imaging》 2017年第4期131-143,共13页
Magnetic resonance elastography (MRE) allows the quantitative assessment of the stiffness of tissues based on the tissue response to oscillatory shear stress. Shear wave displacements of the tissues are encoded as pha... Magnetic resonance elastography (MRE) allows the quantitative assessment of the stiffness of tissues based on the tissue response to oscillatory shear stress. Shear wave displacements of the tissues are encoded as phase shifts and converted to stiffness (elastogram). Generally, a partial volume effect occurs when different materials are encompassed on the same voxel. In MRE, however, the partial volume effect occurs even if the voxel is filled with the same materials because wave displacements due to vibrations are spatially distributed. The purpose of this study was to investigate how the partial volume effect can affect the phase shift and the elastogram in MRE. We assumed that the partial volume effect appears only in the slice thickness direction and performed a simulation and MRE experiment with various slice thicknesses (1 - 19 mm), two types of imaging plane (coronal and axial) and two types of vibration frequency (100 and 200 Hz). The results of the simulation and the MRE experiment were similar, and indicated that the phase shift and the elastogram changed variously depending on the slice thickness, the wave pattern and the vibration frequency, even if the voxel was filled with the same material. To reduce the partial volume effect, it is necessary to perform the MRE under the following conditions: Use a wave pattern which barely causes this artefact, a smaller voxel size and a lower vibration frequency. 展开更多
关键词 Magnetic RESONANCE ELASTOGRAPHY partial Volume effect ARTEFACT ELASTICITY VISCOELASTICITY
暂未订购
Effect of the Partial Substitution of V for Nb on the Magnetic Properties of Fe-based Nanocrystalline Alloy
6
作者 Guiqin ZHOU, Fazeng LIAN and Guozhen LI (Institute of Materials and Metallurgy, Northeastern University, Shenyang 110006,China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第6期643-644,共2页
The variation of the magnetic properties of the nanocrystalline alloys for the partial substitution of V for Nb with crystallizing treatment temperature and time was investigated. The variation law of the magnetic pro... The variation of the magnetic properties of the nanocrystalline alloys for the partial substitution of V for Nb with crystallizing treatment temperature and time was investigated. The variation law of the magnetic properties with the annealing temperature and time is essentially the same. The magnetic properties of the Fe-based nanocrystalline alloys for the partial substitution of V for Nb reduce, and the crystallizing treatment temperature of the alloys increases. The optimum properties of Fe74Cu1Nb3Si13B9 nanocrystalline alloys crystallized at 550℃x60 min are μ0=9.2xl0^4, μm=54.8xl0^4, Hc=1.14 A/m and Bs=1.26 T. The best properties for Fe74Cu1Nb3Si13B9 alloys annealed at 560℃x60 min are μ0=8.79x10^4, μm=50.18xl0^4, Hc=1.26 A/m and Bs=1.24 T. 展开更多
关键词 Fe effect of the partial Substitution of V for Nb on the Magnetic Properties of Fe-based Nanocrystalline Alloy
在线阅读 下载PDF
Effect of topiramate on partial excitatory amino acids in hippocampal dentate gyrus of rats after alcohol withdrawal
7
作者 Qinghua Yang Guang Wu +2 位作者 Haiying Jiang Yuanzhe Jin Songbiao Cui 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第2期147-150,共4页
BACKGROUND: Many researches have indicated that the imbalances of various amino acid transmitters and neurotransmitters in brain are involved in the formation of alcohol withdrawal, especially that glutamic acid is o... BACKGROUND: Many researches have indicated that the imbalances of various amino acid transmitters and neurotransmitters in brain are involved in the formation of alcohol withdrawal, especially that glutamic acid is one of the important transmitters for alcohol tolerance in central nervous system. OBJECTIVE: To observe the changes of excitatory amino acids in hippocampal dentate gyrus in rats with long-term alcohol drinking after withdrawal under consciousness, and investigate the therapeutic effect of topiramate on alcohol withdrawal. DESIGN : A randomized control animal experiment SETTING : Department of Neurology, Affiliated Hospital of Yanbian University MATERIALS: Thirty male Wistar rats of 4 months old, weighing 300-350 g, were purchased from the Experimental Animal Department, Medical College of Yanbian University. Topiramate was produced by Swish Cilag Company, and the batch number was 02CS063. METHODS: The experiments were carried out in the Department of Physiology, Medical College of Yanbian University from August 2005 to February 2006. ① The rats were divided randomly into three groups: control group (n=10), alcohol group (n=10) and topiramate-treated group (n=10). Rats in the alcohol group and topiramate-treated group were given intragastric perfusion of 500 g/L alcohol (10 mL/kg), once a day for 4 weeks successively, and then those in the topiramate-treated group were treated with 80 mg/kg topiramate at 24 hours after the last perfusion of alcohol, once a day for 3 days successively. Rats in the control group were intragastricly given isovolume saline. ② The withdrawal symptoms were assessed at 6, 30, 48 and 72 hours after the last perfusion of alcohol by using the withdrawal rating scale set by Erden et al, which had four observational indexes of stereotyped behaviors, agitation, tail stiffness and abnormal posture, each index was scored by 5 points, the higher the score, the more obvious the symptoms. ③ The contents of aspartic acid and glutamic acid in hippocampal dentate gyrus were detected with microdialysis technique and high-performance liquid chromatograpy (HPLC) respectively at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the three groups. MAIN OUTCOME MEASURES : ① Scoring results of alcohol withdrawal symptoms; ② Changes of the contents of aspartic acid and glutamic acid in hippocampal dentate gyrus at the alcohol withdrawal symptoms, and the effects of topiramate. RESULTS: Seven rats were excluded due to inaccurate localization and natural death, and 23 rats were involved in the analysis of results. ①In the alcohol group, the scores of alcohol withdrawal symptoms at 30 and 48 hours after the last perfusion of alcohol were obviously higher than those in the control group (10.50±0.96, 14.17±1.25; 3.50±0.92, 3.16±0,31; P 〈 0.01). In the topiramate-treated group, the scores at 30 hours after the last perfusion of alcohol (6.06±0.82, 3.50±0.92, P 〈 0.05), and the withdrawal scores at 48 and 72 hours were close to those in the control group (4.57±0.58, 3.30±0.71; 3.16±0.31, 3.66±0.67; P 〉 0.05).② Changes of the contents of glutamic acid in hippocampal dentate gyrus: In the alcohol group, the content of glutamic acid at 48 hours after the last perfusion of alcohol was significantly increased as compared with that at 6 hours [(143.32±11.42)%, (99.12±0.69)%; P 〈 0.05], and that at 72 hours was close to that at 6 hours [(78.50±16.40)%, (99.12±0.69)%; P 〉 0.05]. The contents of glutamic acid had no obvious differences at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the topiramate-treated group [(100.30±0.37)%, (118.91±10.40)%, (99.55±12.81)%, (99.08±11.42)%; P 〉 0.05], The content of glutamic acid at 48 hours after the last perfusion of alcohol in the topiramate-treated group was obviously lower than that in the alcohol group (P 〈 0.05), and those at 30 and 72 hours were close (P 〉 0.05). ③ Changes of the contents of aspartic acid in hippocampal dentate gyrus: In the alcohol group, the contents of aspartic acid at 30 and 48 hours after the last perfusion of alcohol were significantly increased as compared with that at 6 hours [(126.60±8.67)%, (129.17±10.40)%, (99.25±0.87)%; P 〈 0.05], and that at 72 hours was close to that at 6 hours [(89.87±9.93)%, (99.25±0.87)%; P 〉 0.05]. The contents of aspartic acid had no obvious differences at 6, 30, 48 and 72 hours after the last perfusion of alcohol in the topiramate-treated group [(100.27±0.32)%, (120.81 ±12.63)%, (98.91±7.83)%, (85.92±8.07)%; P 〉 0.05]. The content of aspartic acid at 48 hours after the last perfusion of alcohol in the topiramate-treated group was obviously lower than that in the alcohol group (P 〈 0.05), and those at 30 and 72 hours were close (P 〉 0.05). CONCLUSION: ① The occurrences of alcohol withdrawal symptoms are correlated with the increased contents of excitatory amino acids in hippocampal dentate gyrus in rats. ② Topiramate can alleviate the alcohol withdrawal symptoms, which may be correlated with the decreased contents of excitatory amino acids in hippocampal dentate gyrus in rats. 展开更多
关键词 effect of topiramate on partial excitatory amino acids in hippocampal dentate gyrus of rats after alcohol withdrawal
暂未订购
Impact of back-gate bias on the hysteresis effect in partially depleted SOI MOSFETs
8
作者 罗杰馨 陈静 +4 位作者 周建华 伍青青 柴展 余涛 王曦 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期473-478,共6页
The hysteresis effect in the output characteristics,originating from the floating body effect,has been measured in partially depleted(PD) silicon-on-insulator(SOI) MOSFETs at different back-gate biases.I D hystere... The hysteresis effect in the output characteristics,originating from the floating body effect,has been measured in partially depleted(PD) silicon-on-insulator(SOI) MOSFETs at different back-gate biases.I D hysteresis has been developed to clarify the hysteresis characteristics.The fabricated devices show the positive and negative peaks in the I D hysteresis.The experimental results show that the I D hysteresis is sensitive to the back gate bias in 0.13-渭m PD SOI MOSFETs and does not vary monotonously with the back-gate bias.Based on the steady-state Shockley-Read-Hall(SRH) recombination theory,we have successfully interpreted the impact of the back-gate bias on the hysteresis effect in PD SOI MOSFETs. 展开更多
关键词 floating body effect hysteresis effect back gate bias partially depleted (PD) SOl
原文传递
Efficient Shrinkage Estimation about the Partially Linear Varying Coefficient Model with Random Effect for Longitudinal Data
9
作者 Wanbin Li 《Open Journal of Statistics》 2016年第5期862-872,共12页
In this paper, an efficient shrinkage estimation procedure for the partially linear varying coefficient model (PLVC) with random effect is considered. By selecting the significant variable and estimating the nonzero c... In this paper, an efficient shrinkage estimation procedure for the partially linear varying coefficient model (PLVC) with random effect is considered. By selecting the significant variable and estimating the nonzero coefficient, the model structure specification is accomplished by introducing a novel penalized estimating equation. Under some mild conditions, the asymptotic properties for the proposed model selection and estimation results, such as the sparsity and oracle property, are established. Some numerical simulation studies and a real data analysis are presented to examine the finite sample performance of the procedure. 展开更多
关键词 partially Linear Varying Coefficient Model Mixed effect Penalized Estimating Equation
在线阅读 下载PDF
Effect of doxazosin on rabbit bladder compliance after partial bladder outlet obstruction
10
作者 皇甫雪军 《外科研究与新技术》 2011年第4期243-244,共2页
Objective To explore the effect of doxazosin on rabbit bladder compliance after partial bladder outlet ob- struction. Methods A total of 40 male New Zealand white rabbits were randomized into 4 groups,with 10 rabbits ... Objective To explore the effect of doxazosin on rabbit bladder compliance after partial bladder outlet ob- struction. Methods A total of 40 male New Zealand white rabbits were randomized into 4 groups,with 10 rabbits in each group. Partial bladder outlet 展开更多
关键词 effect of doxazosin on rabbit bladder compliance after partial bladder outlet obstruction der
暂未订购
Open Partial Nephrectomy: One Night Length of Stay Is Safe and Cost Effective
11
作者 Mohit Sirohi Kyrollis Attalla +1 位作者 Harris M. Nagler Erik T. Goluboff 《Open Journal of Urology》 2016年第9期139-146,共9页
Objective: To review our open partial nephrectomy (OPN) experience and compare to known robotic partial nephrectomy (RPN) data to determine whether length of stay (LOS) and morbidity are significant drivers in the sur... Objective: To review our open partial nephrectomy (OPN) experience and compare to known robotic partial nephrectomy (RPN) data to determine whether length of stay (LOS) and morbidity are significant drivers in the surgical approach employed for partial nephrectomy. Methods: We reviewed our OPN experience during the last 3 years examining age, tumor size, LOS, pathology, blood loss, complications, recurences, and deaths. Results: Seventy-five patients underwent OPN during this period. Mean age was 59 years, tumor size 2.8 cm, percent malignant 75%, estimated blood loss 350 cc. With a median follow-up of 18 months, there was one urinoma managed by drain-age, one pseudo aneurysm that required embolization and one pulmonary embolism that required anticoagulation. There were no readmissions, no tumor recurences, and no deaths. Our major complication rate was 4% as compared to other trials that re-ported major complication rates between 1% - 9% for RPN and between 3% - 24% for OPN. In the first half of the experience (n = 37), median LOS was 57 hours. Using a pathway encouraging early ambulation and smaller incisions in the second half of the experience (n = 38), median LOS was 35 hours. This is much shorter than reported RPN LOS of 62 - 67 hours and OPN LOS of 108 - 142 hours. Conclusion: OPN can be performed safely and effectively with one night hospital stay. This provides a more cost-effective approach to partial nephrectomy with similar or better complication rates and calls into question the main value drivers of RPN. 展开更多
关键词 Cost effective Length of Stay Open partial Nephrectomy Robotic partial Nephrectomy
暂未订购
经济增长的动力重估:工业与服务业的协同效应与非线性特征
12
作者 郭英彤 邓志鹏 《财经论丛(浙江财经大学学报)》 北大核心 2025年第9期39-48,共10页
本文基于2000—2023年中国省际分行业数据,通过扩展Feder模型并融合机器学习与面板回归方法,系统考察了工业与服务业对经济增长的差异化贡献及其作用机制。研究发现,工业通过技术进步和产业关联效应成为经济增长的重要驱动力;服务业在... 本文基于2000—2023年中国省际分行业数据,通过扩展Feder模型并融合机器学习与面板回归方法,系统考察了工业与服务业对经济增长的差异化贡献及其作用机制。研究发现,工业通过技术进步和产业关联效应成为经济增长的重要驱动力;服务业在经济增长中发挥着不可替代的作用,特别是金融业通过与工业的协同发展能够显著促进经济增长,而脱离实体经济的金融扩张则可能对经济增长产生抑制作用。本文还揭示了工业发展存在非线性特征,其边际贡献在跨越特定阈值后显著提升。基于实证结果,本文建议产业政策应统筹工业与服务业协同发展以优化资源配置效率,以及金融业需强化服务实体经济功能,促进产业良性互动。本研究为推动产业结构优化升级、实现经济高质量发展提供了理论与实证依据。 展开更多
关键词 经济增长 FEDER模型 机器学习 偏效应分析
在线阅读 下载PDF
政策变化对中国粮食市场供需的影响 被引量:2
13
作者 李俊茹 石自忠 王芳 《农业现代化研究》 北大核心 2025年第1期68-81,共14页
粮食综合生产能力的稳步提升,对加快建设农业强国和促进农业农村现代化发展具有重要意义。本文在量化分析1950—2022年粮食政策文件的基础上,构建中国粮食市场局部均衡模型,把握政策实施对粮食市场供需的既有影响,并模拟未来可能的政策... 粮食综合生产能力的稳步提升,对加快建设农业强国和促进农业农村现代化发展具有重要意义。本文在量化分析1950—2022年粮食政策文件的基础上,构建中国粮食市场局部均衡模型,把握政策实施对粮食市场供需的既有影响,并模拟未来可能的政策变化对粮食市场供需的影响。研究表明:1)中国粮食政策文件数量及政策指数呈现出波动增长的态势,且表现出较为明显的阶段特征。2)粮食安全问题的关注、管理和责任部门逐步呈现多元化,政策制定实施得到不断落实落细。3)粮食政策实施对粮食单位产量和价格具有显著正向影响;粮食政策指数增强助推播种面积和单位面积产量增加,提升粮食供给保障能力,并推动国内粮食食用、饲用及其他消费增长;粮食政策指数降低作用相反。粮食政策对单位面积产量的作用较对播种面积的作用更为明显,粮食增产重心应放在提高单产上;政策实施对粮食饲用消费的影响较食用消费影响更大,未来粮食用途重点应放在饲料粮上。基于此,建议加强粮食政策的法律法规建设,提高粮食政策的连续性、稳定性和协同性;强化粮食生产能力建设,筑牢粮食安全“压舱石”。 展开更多
关键词 政策变化 粮食市场 粮食安全 供需 政策效应 局部均衡模型
原文传递
滨海盐碱土壤-植物系统中Na^(+)调控机制及养分提升路径研究
14
作者 乔雪琴 孙萍 +4 位作者 陈友媛 王翔宇 张方 颜雨欣 杨阳 《中国海洋大学学报(自然科学版)》 北大核心 2025年第11期112-123,共12页
滨海盐碱土壤中Na^(+)过量,养分缺乏,严重制约固碳能力与可持续利用。本研究通过盆栽实验,结合统计分析方法,探讨不同浓度盐胁迫(2.0、6.8)下生物炭和丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)对土壤-植物系统中Na^(+)调控机制... 滨海盐碱土壤中Na^(+)过量,养分缺乏,严重制约固碳能力与可持续利用。本研究通过盆栽实验,结合统计分析方法,探讨不同浓度盐胁迫(2.0、6.8)下生物炭和丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)对土壤-植物系统中Na^(+)调控机制及养分有效性的影响及其作用路径。结果表明,盐浓度对植物生长呈现“低盐促进、高盐抑制”的趋势,H_(3)PO_(4)改性生物炭和AMF的协同作用在缓解盐胁迫损害方面发挥更优作用。2.0盐度下,H_(3)PO_(4)改性生物炭和AMF的联合作用使植物叶绿素、鲜质量和株高比对照组分别增加了45.8%、99.2%和48.0%;Na^(+)从土壤向植物的迁移变化量比对照组提高了5.3倍,显著抑制了有毒Na^(+)向植物根系的迁移。通过聚类分析和偏最小二乘路径模型,揭示并量化了H_(3)PO_(4)改性生物炭和AMF在盐碱土壤-植物系统中调控Na^(+)机制并提高养分有效性的相互作用路径:H_(3)PO_(4)改性生物炭对土壤调节作用更强,通过含氧官能团的吸附和离子交换能力,有效固定Na^(+),改善土壤通气性和渗透性,增强土壤养分有效性,间接促进植物生长;AMF对植物调节作用更积极,通过改善渗透调节,强化光合作用,提升根系活力,提高植物耐盐性,促进植物生物量的积累。生物炭和AMF的协同机制为滨海盐碱地植被恢复和生态景观构建提供了重要理论依据与实践指导。 展开更多
关键词 盐胁迫 生物炭 丛枝菌根真菌(AMF) 养分有效性 偏最小二乘路径模型
在线阅读 下载PDF
宏观经济不确定性、地区金融发展与外商直接投资——理论模型和经验证据
15
作者 张国建 胡玉梅 唐浩 《系统工程》 北大核心 2025年第2期114-127,共14页
以2005-2021年中国省级面板数据为样本,运用系统广义矩估计方法,着重考察了宏观经济不确定性与地区金融发展在外商直接投资(FDI)流入中发挥的作用及两者间是否存在相互促进或是抑制效应。研究发现:(1)地区金融发展与FDI流入之间存在倒U... 以2005-2021年中国省级面板数据为样本,运用系统广义矩估计方法,着重考察了宏观经济不确定性与地区金融发展在外商直接投资(FDI)流入中发挥的作用及两者间是否存在相互促进或是抑制效应。研究发现:(1)地区金融发展与FDI流入之间存在倒U形非线性关系;(2)剥离偏效应后,宏观经济不确定性对FDI的流入仍然存在显著的负向抑制作用;(3)随着地区金融发展水平的提高,宏观经济不确定性的负向影响会被弱化。宏观层面的经验证据支持了理论模型的初步分析,而且实证结果具有稳健性。 展开更多
关键词 外商直接投资 不确定性 地区金融发展 偏效应
原文传递
RCEP关税减让的贸易与福利效应——基于汽车制造业产业链的局部均衡分析 被引量:1
16
作者 艾玮炜 杨继军 《南开经济研究》 北大核心 2025年第3期114-134,共21页
本文基于汽车制造业产业链视角,采用可计算的局部均衡GSIM模型前瞻性评估RCEP关税减让对汽车上游零部件、下游整车产品的贸易与福利效应。模拟结果表明:对于贸易环节而言,RCEP关税减让安排通过削减进口成本扩大区域内汽车产业贸易规模,... 本文基于汽车制造业产业链视角,采用可计算的局部均衡GSIM模型前瞻性评估RCEP关税减让对汽车上游零部件、下游整车产品的贸易与福利效应。模拟结果表明:对于贸易环节而言,RCEP关税减让安排通过削减进口成本扩大区域内汽车产业贸易规模,优化RCEP域内汽车制造业产业链的生产布局以构建“链式”创新汽车生产体系;对于生产环节而言,无论是产业链上游零部件产品还是下游整车产品,RCEP成员国日本、韩国的国内产量均有所增加,澳大利亚、新西兰的国内产量均有所下降,而中国汽车整车产品的产出将会增加0.02%,东盟汽车整车产品的产量将会下降0.09%;对于福利效应水平而言,RCEP关税减让将显著提升日本、韩国、东盟的社会福利总水平,而中国在上游零部件环节因降税幅度较大,消费者福利难以弥补关税损失,零部件制造环节的社会福利效应将会减少13.9亿美元。本文认为,要充分利用RCEP关税减让安排,推动区域汽车产业链、供应链深度融合;予以汽车关键零部件政策支持,推进汽车产业链上下游对接合作模式;防范关税减让对关税收入的冲击,最大限度提升汽车产业链的福利效应水平。 展开更多
关键词 RCEP 汽车制造业产业链 局部均衡 贸易效应 福利效应
在线阅读 下载PDF
不同杂质缺陷对电缆中间接头电气性能的影响研究
17
作者 黄博 杨铭远 +3 位作者 聂永杰 赵学童 徐学帅 李洪伟 《电工电能新技术》 北大核心 2025年第9期42-54,共13页
电缆接头在电力传输系统中起到至关重要的作用,但电缆接头制作过程中不可避免地引入各种杂质缺陷,对电力电缆的长期可靠运行带来严重的安全隐患。本文采用有限元仿真和试验相结合的方法,研究了不同类型的杂质缺陷对电缆中间接头电气性... 电缆接头在电力传输系统中起到至关重要的作用,但电缆接头制作过程中不可避免地引入各种杂质缺陷,对电力电缆的长期可靠运行带来严重的安全隐患。本文采用有限元仿真和试验相结合的方法,研究了不同类型的杂质缺陷对电缆中间接头电气性能的影响,通过COMSOL Multiphysics软件建立了10 kV电缆中间接头三维模型,设置了电缆接头运行环境中典型的金属杂质、半导电杂质、粉尘和受潮等缺陷,开展电场仿真计算。同时,制作无缺陷和含不同缺陷的中间接头试样,进行局部放电和耐压试验。结果表明,不同类型的缺陷对电缆中间接头的电场分布和局部放电特性均有显著影响,其中铜杂质和半导电层的残留对电气性能影响最大,造成电缆交联聚乙烯(XLPE)绝缘击穿,受潮缺陷局部放电量高,粉尘缺陷影响较小。本文提出了不同缺陷对电缆中间接头电气性能的影响规律,为电缆中间接头的运行和维护提供了理论参考。 展开更多
关键词 电缆接头 杂质缺陷 电气性能 仿真计算 局部放电
在线阅读 下载PDF
部分饱和岩样中震电响应的实验测量研究
18
作者 聂成洋 王军 +2 位作者 韦庆华 关威 胡恒山 《地球物理学报》 北大核心 2025年第8期3258-3267,共10页
含流体孔隙介质因双电层的存在可引发一种弹性-电磁耦合效应(震电效应).该效应产生的转换波场兼具弹性波的空间分辨率和电磁波的电化学敏感性,进而受到地球物理学界的广泛关注.然而当前有关震电效应的理论模拟及实验测量大多基于单一流... 含流体孔隙介质因双电层的存在可引发一种弹性-电磁耦合效应(震电效应).该效应产生的转换波场兼具弹性波的空间分辨率和电磁波的电化学敏感性,进而受到地球物理学界的广泛关注.然而当前有关震电效应的理论模拟及实验测量大多基于单一流体饱和模型展开,这与多种流体夹杂饱和的实际复杂地层情况不符.因此,本文重点针对部分流体饱和情况下的震电响应问题,在实验室内开展岩样内部震电波场的观测分析研究.根据地下流体饱和度的渐变分布形式,设计一种可实现部分流体饱和的实验模型,并通过内嵌电极的布置方式,开展岩样内部随震电场和界面电磁波的实验测量,记录这两种转换波场的时域波形,讨论他们在部分饱和情况下的传播特性,分析他们的幅值衰减变化规律,对比二者对饱和度差异的敏感性,研究饱和界面对震电耦合波场的影响.实验结果表明:在岩样内部可以观测到直达随震纵波、岩石上表面的反射震电场及饱和度界面激发的界面电磁波,其幅值衰减符合指数变化规律.随震纵波振幅和波速对饱和度敏感性较低,但界面电磁波在不同饱和度岩样中传播时存在明显的幅值差异.因此可利用震电转换信号识别复杂储层中的饱和度分界面,这为油气定位和储量判断提供了重要参考依据. 展开更多
关键词 震电效应 部分饱和 界面电磁波 伴随震电场
在线阅读 下载PDF
地方分权视角下中国区域经济增长的空间分异与发展对策研究
19
作者 邓楚瑶 王福友 《工程管理科技前沿》 北大核心 2025年第2期83-89,共7页
中央与地方政府分权给予了地方政府更多的经济自主权,通过影响地方政府行为、物质资本供给、人力资本供给、技术水平进步及公共产品服务对地区经济增长具有一定的正向促进作用。本文基于地方分权视角,利用我国2000-2020年30个省市的面... 中央与地方政府分权给予了地方政府更多的经济自主权,通过影响地方政府行为、物质资本供给、人力资本供给、技术水平进步及公共产品服务对地区经济增长具有一定的正向促进作用。本文基于地方分权视角,利用我国2000-2020年30个省市的面板数据,构建空间计量模型,探究中国区域经济增长的空间分异的影响因素,结果表明:我国30个省市的经济增长呈现明显的正空间自相关性;地方分权程度、技术水平、城镇化水平提升能够产生明显的空间溢出效应,不仅能够促进本地经济增长,同时能够带动周围地区经济增长;产业结构水平则在促进本地经济增长的基础上,对周围地区经济增长产生抑制效应,但抑制效应并不明显;人力资本水平能够促进本地经济增长,对周围地区经济增长也会产生溢出效应,但溢出效应并不明显。本文研究结果对提升中国区域经济发展水平具有一定的借鉴意义。 展开更多
关键词 地方分权 区域经济增长 固定效应 空间计量模型偏微分方法
在线阅读 下载PDF
部分奥氏体逆转变工艺对Fe-8Mn-0.2C-3Al中锰钢组织性能的影响 被引量:1
20
作者 刘明珠 丁桦 邹宇明 《金属热处理》 北大核心 2025年第2期90-95,共6页
对Fe-8Mn-0.2C-3Al中锰钢采用两步退火的部分奥氏体逆转变(PART)工艺,通过场发射扫描电镜、X射线衍射仪、万能试验机等对试验钢的微观组织和力学性能进行研究。结果表明,随着第一步退火温度的提高,PART工艺处理试验钢的奥氏体含量由49.7... 对Fe-8Mn-0.2C-3Al中锰钢采用两步退火的部分奥氏体逆转变(PART)工艺,通过场发射扫描电镜、X射线衍射仪、万能试验机等对试验钢的微观组织和力学性能进行研究。结果表明,随着第一步退火温度的提高,PART工艺处理试验钢的奥氏体含量由49.7%逐渐下降至21.6%,组织呈板条状,屈服强度逐渐升高,抗拉强度和伸长率逐渐下降。755℃×15 min+620℃×30 min处理试验钢获得优秀力学性能,抗拉强度1087 MPa,伸长率43.4%,强塑积47.2 GPa·%,这是由于适中的奥氏体稳定性可以在拉伸过程中充分发挥TRIP效应,提高材料的综合力学性能。 展开更多
关键词 Fe-8Mn-0.2C-3Al中锰钢 部分奥氏体逆转变 奥氏体稳定性 TRIP效应 力学性能
原文传递
上一页 1 2 41 下一页 到第
使用帮助 返回顶部