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抗抑郁药物的分类及作用机制研究进展 被引量:7
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作者 尹桂华 《中国民康医学》 2009年第12期1429-1430,共2页
目的:阐述抗抑郁药物分类及作用机制的研究进展。方法:查阅国内外相关文献,进行分析归纳。结果:抑郁症的防治已引起世界范围内的重视。结论:抑郁症将会有很好的治疗效果。
关键词 抗抑郁药物 作用机制
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螺旋气道变截面进气的缸内充量分层模拟研究
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作者 段齐旺 张韦 +1 位作者 蒋倩昱 陈朝辉 《农业装备与车辆工程》 2020年第3期17-21,27,共6页
构建了YN33共轨柴油机螺旋气道-气门-气缸的CAD模型,划分螺旋气道的进气口为不同进气截面,并通过在各个截面分区进气,以及时序分区进气实现缸内的充量分层。研究表明:变截面进气时,进气截面下半部进气量比上半部进气量多7%,而右下区的... 构建了YN33共轨柴油机螺旋气道-气门-气缸的CAD模型,划分螺旋气道的进气口为不同进气截面,并通过在各个截面分区进气,以及时序分区进气实现缸内的充量分层。研究表明:变截面进气时,进气截面下半部进气量比上半部进气量多7%,而右下区的进气会在缸内形成较为均匀的分布,其它区域进气则会形成浓度场各异的分布特性。三段时序进气条件下,4个区域进气对缸内进气总量贡献的差异由前段进气与后段进气所决定,且后段进气影响更大;在分布特性上,进气截面右上区和右下区的前段进气会在缸内形成明显的上稀、下浓分布特点,而后段进气均会在缸内形成上浓、下稀的分布。 展开更多
关键词 柴油机 区、时序 充量 数值模拟
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220kV母线倒闸过程隐患分析及改进建议
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作者 赖泳迪 《今日自动化》 2021年第3期54-55,共2页
随着当今电力行业的不断发展,220 kV母线也得到了广泛应用。而在220 kV母线的倒闸过程中,母联断路器、隔离刀闸、辅助触点等都属于危险点,一旦操作出现问题,便会预留诸多的安全隐患。基于此,对220 kV母线倒闸过程中的隐患进行分析,并针... 随着当今电力行业的不断发展,220 kV母线也得到了广泛应用。而在220 kV母线的倒闸过程中,母联断路器、隔离刀闸、辅助触点等都属于危险点,一旦操作出现问题,便会预留诸多的安全隐患。基于此,对220 kV母线倒闸过程中的隐患进行分析,并针对这些隐患提出了相应的改进建议,避免误操作情况所导致的不利影响。 展开更多
关键词 电力系统 220KV母线 倒闸隐患 建议
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低频部署下MIMO-OFDM通信系统的频谱利用效率分析
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作者 樊恒波 李秀成 王江超 《通信电源技术》 2024年第4期34-36,共3页
主要深入研究低频部署下多进多出-正交频分复用(Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing,MIMO-OFDM)通信系统的频谱利用效率,探讨低频部署对系统性能的影响,并提出相应的优化策略。详细分析低频部... 主要深入研究低频部署下多进多出-正交频分复用(Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing,MIMO-OFDM)通信系统的频谱利用效率,探讨低频部署对系统性能的影响,并提出相应的优化策略。详细分析低频部署对信号传输性能和频谱利用效率的影响,评估频谱利用效率,提出针对低频部署的MIMO-OFDM系统的优化策略,最后探讨低频部署下MIMO-OFDM系统的适用场景,为实际应用提供一些建议。 展开更多
关键词 多出-正交频复用(MIMO-OFDM) 低频部署 频谱利用效率
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基于抛物方程法的部分森林覆盖山区电波传播分析 被引量:9
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作者 郭建炎 王剑莹 +1 位作者 龙云亮 龚主前 《电波科学学报》 EI CSCD 北大核心 2008年第6期1045-1050,共6页
基于Fourier分步步进法的抛物方程模型求解了山区不规则地形部分森林覆盖环境的电波传播,并分析了森林对电波传播的影响。模型中为了简化边界条件,地形用分段线性函数来近似。然后预测了一个山区部分针叶林覆盖环境的电波传播,得到的结... 基于Fourier分步步进法的抛物方程模型求解了山区不规则地形部分森林覆盖环境的电波传播,并分析了森林对电波传播的影响。模型中为了简化边界条件,地形用分段线性函数来近似。然后预测了一个山区部分针叶林覆盖环境的电波传播,得到的结果与实测数据进行对比,二者吻合很好。最后对算法的稳定性与误差进行了分析,本文的模型能处理不规则地形、森林等复杂环境且算法效率高。 展开更多
关键词 抛物方程法 Fourier步步 森林覆盖 电波传播 地形
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KYN28型手车式开关柜智能化的探究与分析 被引量:4
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作者 李耀杰 张辉 《电气传动自动化》 2017年第4期30-32,45,共4页
介绍了KYN28型手车式开关柜智能化的应用前景、基本组件,分析了智能控制单元的工作原理、电动进出车及电动分合接地开关控制原理及运行、电气五防联锁操作流程及底盘车的工作方式,并对可视化技术的应用进行了展望。
关键词 智能单元 电动出车及电动合接地开关控制 五防联锁操作流程
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Regularized Inverse Covariance Estimation for Longitudinal Data with Informative Dropout
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作者 YANG Shuning ZHENG Zhi ZHANG Weiping 《应用概率统计》 CSCD 北大核心 2024年第6期1016-1039,共24页
This paper proposes a novel method for estimating the sparse inverse covariance matrixfor longitudinal data with informative dropouts. Based on the modified Cholesky decomposition,the sparse inverse covariance matrix ... This paper proposes a novel method for estimating the sparse inverse covariance matrixfor longitudinal data with informative dropouts. Based on the modified Cholesky decomposition,the sparse inverse covariance matrix is modelled by the autoregressive regression model,which guarantees the positive definiteness of the covariance matrix. To account for the informativedropouts, we then propose a penalized estimating equation method using the inverse probabilityweighting approach. The informative dropout propensity parameters are estimated by the generalizedmethod of moments. The asymptotic properties are investigated for the resulting estimators.Finally, we illustrate the effectiveness and feasibility of the proposed method through Monte Carlosimulations and a practical application. 展开更多
关键词 penalized estimating function modified Cholesky decomposition DROPOUT inverse probability weighting
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Research Progress of Molecular Clock 被引量:2
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作者 龙承星 张波 马绍宾 《Agricultural Science & Technology》 CAS 2012年第12期2496-2498,2553,共4页
In the paper, related research and progress of molecular clock hypothesis were summarized, including definition of molecular clock, supporting proofs, contro- versy, significance and perfection, application and accomp... In the paper, related research and progress of molecular clock hypothesis were summarized, including definition of molecular clock, supporting proofs, contro- versy, significance and perfection, application and accompanying challenges. 展开更多
关键词 Molecular clock Molecular clock hypothesis Slowing-down of evolution Rate of molecular evolution
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Genome-wide Analysis of Glucose-6-phosphate Dehydrogenase(G6PDH) and Its Evolution in Eucalyptus grandsis 被引量:3
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作者 林元震 张志毅 +1 位作者 林善枝 刘纯鑫 《Agricultural Science & Technology》 CAS 2011年第9期1276-1278,共3页
[Objective] The aim of this study was to perform genome-wide analysis of glucose-6-phosphate dehydrogenase(G6PDH) and reveal its evolution in Eucalyptus grandsis.[Method] The gene character,protein sequence and phyl... [Objective] The aim of this study was to perform genome-wide analysis of glucose-6-phosphate dehydrogenase(G6PDH) and reveal its evolution in Eucalyptus grandsis.[Method] The gene character,protein sequence and phylogenetic tree of G6PDH gene were analyzed by BLAST and other bioinformatics software within Eucalyptus grandsis whole genome database.[Result] Six G6PDH genes,including one cytomic type and five plastids,were detected in the E.grandsis genome.All the G6PDHs have conserved motifs of motif 1,motif 2,motif 3,motif 7,motif 9 and motif 11.Furthermore,promoter sequences of all E.grandsis G6PDH contain TATA box,enhancer,light-responsive,hormone-responsive and stress-responsive regulatory elements.[Conclusion] This study provided reference for the further revealing molecular function of E.grandsis G6PDH gene family 展开更多
关键词 Eucalyptus grandsis Glucose-6-phosphate dehydrogenase Evolution analysis Conserved motif
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A Class of Fractal Functions and Their Dimension Estimates 被引量:4
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作者 王宏勇 杨守志 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第4期84-90,共7页
本文作者首先借助于b进制分数及无穷级数构造了一类分形函数,然后研究了这些函数图象的分形维数及其Hoelder性质,得到了一些维数结果。
关键词 b-adic fraction fractal function fractal dimension Holder continuity
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Molecular Composition and Evolution of the Chalcone Synthase (CHS) Gene Family in Five Species of Camellia (Theaceae) 被引量:5
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作者 杨俊波 田欣 +1 位作者 李德铢 郭振华 《Acta Botanica Sinica》 CSCD 2003年第6期659-666,共8页
The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from... The molecular composition and evolution of the chalcone synthase (CHS) gene family from five species in Camellia (Theaceae) are explored in this study. Sixteen CHS exon 2 from four Camellia species were amplified from total DNA by PCR method. Three sequences of the fifth species in Camellia and two sequences of Glycine max as the designated outgroups were obtained from GenBank. Our results indicated that CHS gene family in Camellia was differentiated to three subfamilies (A, B, C) during the evolutionary history with six groups (A1, A2, A3, BI, B2, C). Among them, only group A2 was possessed by all five species in this study. However, the other five groups were detected only in some species of the plants studied. All members of CHS gene family in this study had high sequence similarity, more than 90% among the members in the same subfamily and more than 78% among different subfamilies at nucleotide level., According to the estimated components of amino acids, the function of CHS genes in Camellia had been diverged. The nucleotide substitutions of the different groups were not identical. Based on phylogenetic analyse inferred from sequences of CHS genes and their deduced amino acid sequences, we concluded that the CHS genes with new function in this genus were evolved either by mutations on several important sites or by accumulation of the mutations after the gene duplication. A further analysis showed that the diversification of CHS genes in Camellia still occurred recently, and the evolutionary models were different to some extant among different species. So we assumed that the different evolutionary models resulted from the impacts of variable environmental elements after the events of speciation. 展开更多
关键词 CAMELLIA chalcone synthase (CHS) gene family molecular evolution
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典型场景下电波传播特性建模 被引量:3
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作者 郭淑霞 单雄军 +1 位作者 张政 高颖 《激光技术》 CAS CSCD 北大核心 2015年第1期124-128,共5页
为了解决某些典型场景(如海上、山区、丘陵、城区)下无法使用已有基础模型来全面表达电波传播特性的问题,建立了一种在典型场景下,基于确定性抛物方程、适用于多个传输场景的统一电波传播模型。把典型场景等效为损耗介质层来求解边界条... 为了解决某些典型场景(如海上、山区、丘陵、城区)下无法使用已有基础模型来全面表达电波传播特性的问题,建立了一种在典型场景下,基于确定性抛物方程、适用于多个传输场景的统一电波传播模型。把典型场景等效为损耗介质层来求解边界条件,利用Fourier分步步进法得到相应解,然后得到电波在典型场景下的传播损耗,并进行了理论分析和实验验证。结果表明,在不同传输场景下,将统一电波传播模型与Miller-Brown模型、射线追踪模型进行比较,结果较吻合,验证了其正确性。这一结果对建立一种求解典型场景下电波传播衰落问题的统一电波传播模型是有帮助的。 展开更多
关键词 物理光学 统一电波传播模型 Fourier步步 典型场景 损耗介质层
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Comparative study of two biological nitrogen removal processes:A/O process and step-feeding process 被引量:3
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作者 祝贵兵 彭永臻 +1 位作者 王淑莹 马斌 《Journal of Southeast University(English Edition)》 EI CAS 2008年第4期528-531,共4页
Two biological nitrogen removal processes are compared in the aspect of nitrogen removal, process operation and energy saving. Results show that when the returned sludge ratio is 50% of the inflow rate, the step-feedi... Two biological nitrogen removal processes are compared in the aspect of nitrogen removal, process operation and energy saving. Results show that when the returned sludge ratio is 50% of the inflow rate, the step-feeding process achieves over 80% total nitrogen (TN) removal efficiency, but the TN removal efficiency of the A/O process is only 40%. Moreover, filamentous sludge bulking can be well restrained in the step-feeding process. Given the conditions of a returned sludge ratio of 100% and a nitrifying liquor recycle ratio of 200%, the TN removal efficiency is 78.32% in the A/O process, but the sludge volume index (SVI) value increases to 143 mL/g. In the step-feeding process, the SVI is only 94.4 mL/g when the TN removal efficiency reaches 81. 1%. The step-feeding process has distinct advantages over the A/O process in the aspects of practicability, nitrogen removal and operating stability. 展开更多
关键词 activated sludge biological nitrogen removal A/O process step-feeding process efficiency
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基于张量理论的数控机床误差补偿模型 被引量:6
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作者 褚宁 张为民 《农业机械学报》 EI CAS CSCD 北大核心 2017年第10期408-416,共9页
为了进一步提高数控机床多体运动学误差模型的精度,提出了基于张量理论的机床误差补偿模型。首先面向数控系统列表插值补偿方式,提出了应用张量理论设定基础阶、扩展阶和误差阶来建立机床误差张量模型。然后,提出了采用设定机床信息、... 为了进一步提高数控机床多体运动学误差模型的精度,提出了基于张量理论的机床误差补偿模型。首先面向数控系统列表插值补偿方式,提出了应用张量理论设定基础阶、扩展阶和误差阶来建立机床误差张量模型。然后,提出了采用设定机床信息、建立张量模型及设定检测参数3个流程实施误差补偿,并通过多元回归分析提出了采用4阶多项式拟合机床空间误差。最后,以某重型车铣复合机床实验为例,提出了分轴步进对角线法下的张量误差模型,采用球杆仪进行了圆度误差检测实验,结果表明该方法能够有效地提高机床精度,比多体运动学误差模型的补偿效果更优。 展开更多
关键词 误差补偿 张量理论 轴步对角线法 车铣复合机床
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Barrier Structure Design for Fattening Pigs in Large-scale Pig House with Fermentation Bed
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作者 刘波 唐建阳 +2 位作者 蓝江林 史怀 李兆龙 《Agricultural Science & Technology》 CAS 2014年第12期2249-2252,2270,共5页
[Objective] The large-scale single-column fattening pig house with fermen- tation bed could hold 1 500 heads of fattening pigs. Since the number of pigs in piggery is too large, the management is difficult. The behavi... [Objective] The large-scale single-column fattening pig house with fermen- tation bed could hold 1 500 heads of fattening pigs. Since the number of pigs in piggery is too large, the management is difficult. The behavior of feeding, drinking, movement, sleeping, fighting of pigs is difficult to handle. The pigs cannot be man- aged well, resulting in the enhanced weakness of piglets, enhanced illness of weak pigs and missing treatment of ill pigs. The management for the pig populations is not satisfactory, and thus, it is needed to improve timely. [Method] The barriers for the fattening pigs in the large-scale pig house with fermentation bed were designed. The single management for single fattening pig was proposed. The large-scale fat- tening pig house was divided into 8 regions. Among them, 4 regions were located in both sides of the fermentation bed. Their main function was to separate ill, weak, small and bad pigs. In addition, the main column was divided into 4 gradual barri- ers. They were used to separate different-size fattening pigs. In view of manage- ment, the different-type pigs were managed dividedly with the gradual barriers. The equally-sized pigs were concentrated into one column. The ill, weak, small and bad pigs were isolated into barriers. Thus, the dynamic management was adopted. Until the fattening pigs grew up to 75 kg and their health was stable, the barriers among the columns were canceled to mix the pigs again and guarantee the pigs more gymnastic space. [Result] This design would improve the disease resistance of ill pigs, health status of weak pigs and management level of pig populations. This study would also provide a basis for the healthy running of large-scale fattening pig house with fermentation bed. [Conclusion] The pig-raising model with fermentation bed would improve the environment of pig house and the welfare of pigs. In addi- tion, the performance of pigs and quality of pork were also improved. The fermen- tation bed had an obvious advantage in safety and economics, and it had a broad application prospect. 展开更多
关键词 Fermentation bed Fattening pigs' management Gradual columns for raising pigs Structure of barriers
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EXPERIMENTAL STUDY OF HTC FOR FILM COOLING OF PARALLEL-INLET HOLES 被引量:2
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作者 杨卫华 张靖周 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2012年第1期46-53,共8页
The parallel-inlet holes with one-row, two-row and three-row film hole arrangements and different di- ameters are proposed to experimentally study their cooling characteristics. Detailed experimental processes and res... The parallel-inlet holes with one-row, two-row and three-row film hole arrangements and different di- ameters are proposed to experimentally study their cooling characteristics. Detailed experimental processes and results are described and carried out. Results indicate that heat transfer coefficient (HTC) is increased with the increase of blowing ratio. When the blowing ratio is lower, the distribution of HTC along the heated wall can be divided into three regions. For larger blowing ratio or diameter, the cooling characteristics oi parallel-inlet film holes are similar to those of convective heat transfer around flat. Furthermore, when hole diameter is deter- mined, the arrangement patterns of film hole and the blowing ratio take a great influence on HTC. 展开更多
关键词 film eooling parallel-inlet hole multiple-row arrangement heat transfer eoeffieient (HTC)
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Genetic Differentiation of A and B Chromosomes Between Common Wheat and Wild Emmer as Revealed by RFLP Analysis 被引量:4
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作者 戎均康 刘宝 《Acta Botanica Sinica》 CSCD 2000年第5期502-506,共5页
To investigate chromosome differentiation of genome A and B between common wheat and wild emmer wheat (Triticum turgidum var. dicoccoides (Koern.) Bowden), the authors conducted a RFLP analysis of the two species usin... To investigate chromosome differentiation of genome A and B between common wheat and wild emmer wheat (Triticum turgidum var. dicoccoides (Koern.) Bowden), the authors conducted a RFLP analysis of the two species using 153 genomic, cDNA and chromosome_specific probes. 75.8% of the probes had detected hybridization polymorphism in at least one of the five restriction enzymes. However, the polymorphic probes were unevenly distributed among different homoeologous groups, between different genomes and in different regions of a single chromosome. Homoeologous group 1 possessed the highest level of polymorphism (96.2%), followed by group 6 and 2 (84.6% and 82.1% respectively). In contrast, only 60%-67% of probes of the other four groups was polymorphic. In most groups the number of probes capable of detecting B chromosome polymorphism was slightly higher than that revealing A chromosome difference (totally 51.8% vs 43.1%). In a single chromosome, RFLP was predominant in the distal region (65.1%) and showed a decreasing trend from the proximal (46.2%) to the pericentric (42.4%) regions. The results suggest that there exists a substantial amount of DNA polymorphism between the A and B chromosomes of common wheat and those of wild emmer wheat, indicating that a considerable degree of genetic differentiation has taken place in the A and B genoms of two species during evolution from wild emmer to common wheat. The extent of the genetic differentiation may vary among different homoeologous groups, between A and B chromosomes and in different regions of individual chromosome. 展开更多
关键词 WHEAT chromosome_arm substitution lines genetic differentiation RFLP species evolution
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Expression and Phylogenetic Analysis of Pea Actin Isoforms 被引量:5
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作者 江元清 赵武玲 《Acta Botanica Sinica》 CSCD 2002年第12期1456-1461,共6页
Pea ( Pisum sativum Linn.) actin gene family contains at least three isoforms (PEAcⅠ, PEAcⅡand PEAcⅢ), and the DNA sequence of these isoforms show high similarity in the coding regions and significant divergence... Pea ( Pisum sativum Linn.) actin gene family contains at least three isoforms (PEAcⅠ, PEAcⅡand PEAcⅢ), and the DNA sequence of these isoforms show high similarity in the coding regions and significant divergence in the untranslated regions. RT_PCR and Southern blotting using 3′_untranslated region (3′_UTR) as specific probe revealed that pea isoactin genes were expressed in roots, stems, leaves, tendrils, pollen and juvenile siliques, but displayed different patterns of transcript accumulation. Two_fold serial dilution electrophoresis showed PEAcⅠ mRNA preferentially accumulated in rapidly developing tissues: it peaked in seven days' stem; remained at a rather high level in leaves within a month but decreased significantly later; varied a little in tendrils and reached a median and a very low level respectively in juvenile siliques and in pollen. PEAcⅡ displayed somewhat similar expression pattern to PEAcⅠ. The observed differences in sequences and transcript accumulation patterns suggest that the individual pea actin genes may differ in their transcriptional regulation and cellular function. Phylogenetic tree of actins showed that pea actin isoforms are as diverged from each other as they are from other plant actins, and pea actins might have originated from a common ancestor before the divergence of the dicot and monocot plants. 展开更多
关键词 ACTIN 3′_untranslated region (3′_UTR) differential expression molecular evolution pea ( Pisum sativum )
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Does Environmental Regulation Weaken Industrial Competitiveness?Inspirations from China’s Iron and Steel Sector 被引量:3
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作者 邓泳红 张其仔 陈晓东 《China Economist》 2015年第4期72-96,共25页
China's economic growth is heavily influenced by exports, while reconciling environmental regulation and economic growth requires handling the relationship between environmental regulation and industrial competitiven... China's economic growth is heavily influenced by exports, while reconciling environmental regulation and economic growth requires handling the relationship between environmental regulation and industrial competitiveness well. The effects of environmental regulation on industrial competitiveness are largely subject to the institutional design of environmental regulation. Despite numerous studies on the relationship between environmental regulation and industrial competitiveness, a consensus has yet to be reached. Aside from differences in research methodology, these studies failed to give sufficient consideration to the impact of environmental regulation on industrial competitiveness. Such effects can be negative or positive depending on the design of environmental regulatory policy. This paper has investigated the relationship between environmental regulation and the competitiveness of China's iron and steel industry and discovered that tighter environmental regulation does not diminish the competitiveness of the iron and steel industry since the policy design of environmental regulation accommodates the tolerance of advanced production capacity and includes a reasonable cost sharing mechanism. This discovery is of important reference for China to develop rational policy design to balance the relationship between environmental regulation and industrial competitiveness. 展开更多
关键词 environmental regulation industrial competitiveness iron and steel industry ADF aneed produetion capacity cost sharing mechanism
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Sequence and Molecular Evolution Analysis of Ubiquitin Proteins Encoded by Baculoviruses
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作者 郭忠建 朱颖敏 陈克平 《Agricultural Science & Technology》 CAS 2010年第9期53-57,共5页
[Objective] The aim of this study was to analyze the sequence characteristics and molecular evolution of ubiquitins encoded by baculoviruses.[Methods]Clustal W software was used for multiple sequence alignment analysi... [Objective] The aim of this study was to analyze the sequence characteristics and molecular evolution of ubiquitins encoded by baculoviruses.[Methods]Clustal W software was used for multiple sequence alignment analysis,and neighbor-joining method(NJ)and maximum parsimony method(MP)were used for the construction of phylogenetic tree.[Results]The baculoviral ubiquitins showed 73%-86% sequence identity to eukaryotic ubiquitin.Two heterogeneous regions of baculoviral ubiquitins were observed:one was the residues from 15-32,the other was located from residues 53 to 60.The else parts were conserved,where many functional amino acids were also observed.Phylogenetic analysis indicated that baculoviral ubiquitins could be divided into three sub-families,including sub-family GV,sub-family I and sub-family II.The molecular evolution of baculoviral ubiquitins might be under negative selection to maintain their functional and structural stability.[Conclusion]The analysis had provided reference for the researches on functional characterization of baculoviral ubiquitins. 展开更多
关键词 BACULOVIRUS UBIQUITIN SEQUENCE Molecular evolution
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