基于MVDR波束形成的FDA平台外干扰抑制

针对频控阵(frequency diverse array, FDA)在对与目标位置相近的平台外干扰进行抑制时, 传统FDA与非线性频偏结合不能实现距离-角度去耦合、对数递增FDA主瓣展宽较大和汉明窗加权FDA距离维旁瓣过高的问题, 在充分研究汉明窗加权的线性FDA(Hamming linear FDA, HL-FDA)方案的基础上, 对4种频偏方案的性能进行了分析, 提出采用FDA多输入多输出结构代替传统的一维均匀线性FDA结构, 通过结合最小方差无失真响应(minimum variance distortion free respinse, MVDR)准则, 将HL-FDA应用到MVDR自适应波束形成层面, 对平台外干扰进行抑制。仿真验证了HL-FDA在结合MVDR自适应波束形成算法后能有效地对抗距离-角度二维平台外干扰。     

草麻黄提取物对小菜蛾的生物活性研究

研究草麻黄提取产物对小菜蛾生物活性的影响.结果表明,当提取液处理浓度为500g/L时,氯仿、甲醇、乙醇、丙酮和石油醚的提取物可引起小菜蛾幼虫死亡,其死亡率分别为82%,64%,62%,48%,46%,且都随提取物浓度的降低而减小;5种溶剂的提取物对小菜蛾的卵都具有一定的毒杀作用,作用最强的为高浓度(500g/L)的氯仿提取物;卵的孵化率随提取物浓度的升高而显著降低,提取物对小菜蛾的初孵幼虫具有一定的杀死作用,当浓度为500g/L时,氯仿提取物可引起90%的小菜蛾初孵幼虫的死亡.     

中原经济区中心城市城区新型城镇化水平综合评价研究

结合中原经济区中心城市发展实际,总结出中原经济区中心城市城区新型城镇化综合评价的指标体系,包括二级指标6类,即城市人口与地域指标、城市经济指标、城市生活方式指标、城市发展潜力指标、城市基础设施指标、城市生态环境指标,三级指标21类.对指标体系进行主成分分析和Q聚类分析,对中原经济区中心城市城区新型城镇化水平做出对比,将中原经济区中心城市城区新型城镇化发展水平划分为4类,在此基础上对4类城市新型城镇化发展的特点进行归纳总结.     

超长双层网壳结构自振特性

对超长网壳结构同一面层的杆件进行不同数量的替换，通过结果的对比总结了替换数目对结构的影响，分析表明替换杆件的数量的增多能够提高地震控制的效果，但不是越多越好，要经过计算分析控制在一定的数量。     

Semiparametric Preference Learning

Unlike traditional supervised learning problems,preference learning learns from data available in the form of pairwise preference relations between instances.Existing preference learning methods are either parametric or nonparametric in nature.We propose in this paper a semiparametric preference learning model,abbreviated as SPPL,with the aim of combining the strengths of the parametric and nonparametric approaches.SPPL uses multiple Gaussian processes which are linearly coupled to determine the preference relations between instances.SPPL is more powerful than previous models while keeping the computational complexity low （linear in the number of distinct instances）.We devise an efficient algorithm for model learning.Empirical studies have been conducted on two real-world data sets showing that SPPL outperforms related preference learning methods.     

Abnormal kynurenine pathway of tryptophan catabolism in cardiovascular diseases

Kynurenine pathway (KP) is the primary path of tryptophan (Trp) catabolism in most mammalian cells. The KP generates several bioactive catabolites, such as kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykynurenine (3-HK), xanthurenic acid (XA), and 3-hydroxyanthranilic acid (3-HAA). Increased catabolite concentrations in serum are associated with several cardiovascular diseases (CVD), including heart disease, atherosclerosis, and endothelial dysfunction, as well as their risk factors, including hypertension, diabetes, obesity, and aging. The first catabolic step in KP is primarily controlled by indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO). Following this first step, the KP has two major branches, one branch is mediated by kynurenine 3-monooxygenase (KMO) and kynureninase (KYNU) and is responsible for the formation of 3-HK, 3-HAA, and quinolinic acid (QA); and another branch is controlled by kynurenine amino-transferase (KAT), which generates KA. Uncontrolled Trp catabolism has been demonstrated in distinct CVD, thus, understanding the underlying mechanisms by which regulates KP enzyme expression and activity is paramount. This review highlights the recent advances on the effect of KP enzyme expression and activity in different tissues on the pathological mechanisms of specific CVD, KP is an inflammatory sensor and modulator in the cardiovascular system, and KP catabolites act as the potential biomarkers for CVD initiation and progression. Moreover, the biochemical features of critical KP enzymes and principles of enzyme inhibitor development are briefly summarized, as well as the therapeutic potential of KP enzyme inhibitors against CVD is briefly discussed.     

Collaborative Project Management: A Systemic Approach to Heavy Equipment Manufacturing Project Management

Quite often over the last decade, heavy equipment manufacturers are trying to improve their project management performance with the use of effective project management methods. However, the challenges encountered aren’t isolated problems and a systemic approach is required. This paper exemplifies how a systemic approach can be applied to heavy equipment manufacturing project (HEMP) management, through of a multifaceted vision. The findings present in the paper are based on a two-year case study in a metallurgic equipment manufacturing enterprise in China. Based on the analysis of HEMP management problems and the contributions on systemic approach application in project management, the paper enriches existing theory by: (1) interpreting the HEMP management system with the top-down disassembly method; (2) developing the collaborative project management approach with a systems view highlighting the project characteristics management and inter-departmental collaboration; (3) making suggestions for systemic approach application in project management. For practitioners and researchers, the findings are particularly meaningful for manufacturing project management and systemic approach application.     

Aptamer and its applications in neurodegenerative diseases

Aptamers are small single-stranded DNA or RNA oligonucleotide fragments or small peptides, which can bind to targets by high affinity and specificity. Because aptamers are specific, non-immunogenic and non-toxic, they are ideal materials for clinical applications. Neurodegenerative disorders are ravaging the lives of patients. Even though the mechanism of these diseases is still elusive, they are mainly characterized by the accumulation of misfolded proteins in the central nervous system. So it is essential to develop potential measures to slow down or prevent the onset of these diseases. With the advancements of the technologies, aptamers have opened up new areas in this research field. Aptamers could bind with these related target proteins to interrupt their accumulation, subsequently blocking or preventing the process of neurodegenerative diseases. This review presents recent advances in the aptamer generation and its merits and limitations, with emphasis on its applications in neurodegenerative diseases including Alzheimer’s disease, Parkinson’s disease, transmissible spongiform encephalopathy, Huntington’s disease and multiple sclerosis.     

三角网格模型五轴加工刀轴矢量调整及优化

为消除全局干涉,提出了一种基于K-D树及刀具离散的高效刀轴矢量调整算法.算法首先以有限个点离散表示刀具,然后利用K-D树快速查找刀具的可能干涉点,并在此基础上计算调整后的刀轴矢量.为避免过大的刀轴矢量突变,提出一种分角度区域方法优化刀轴矢量.实例验证表明:算法能够高效实现全局干涉避免及刀轴矢量优化.