Horn Antenna Gain Measurement Based on Vector Network Analyzer

利用微波暗室、矢量网络分析仪、角锥喇叭天线以及电脑等设备建立了一套喇叭天线测量系统;采用两相同天线法,分别测量了4~6 GHz、6~8 GHz角锥喇叭天线的增益值,对测量数据进行误差分析和近距修正;并将增益的实测值与理论计算值进行对比.实验结果表明,近距修正后,所测量的4~6 GHz与6~8 GHz频段天线的增益实测值与理论值的最大偏差值分别为-0.20 dB和-0.19 dB,均在±0.25 dB范围内,符合标准增益天线增益的精度要求,也与天线出厂的指标相符,表明所建立的测量系统对于喇叭天线增益的测量有效可行.中航工业创新基金产学研项目(cxy2013XD28

硫酸介质中氯化物参与下氧化浸出铜渣过程

研究了镍铳选择性氧化浸出产生的铜渣在硫酸介质中氯离子参与下的氧气氧化浸出，考察和比较了氯化物用量、氧气流量、硫酸浓度、温度等因素对铜和镍浸出的影响，并讨论了其原因，确认了在硫酸介质中加入少量氯化物即可在常压下用氧气有效地浸出主要由辉铜矿或类似的硫化铜矿物组成的铜渣

Knowledge Co-Production Process in Information System Development: A Perspective of Intellectual Capital

引入合作共创这一新概念,基于智力资本的视角,提出了检验ISd用户和开发者之间知识共创性的前因和结果变量实证模型,通过267个开发团队的样本数据证实了知识共创性可促进ISd结果,研究结果表明用户和开发者之间的公共知识、关系资本和参与式决策制定过程促进知识共创的有效性。By systematic reviewing and integrating this theory and intellectual capital perspective into this research design,this paper propose a model to examine the antecedents and consequences of knowledge co-production between ISD users and developers.The empirical results verify the hypotheses that knowledge co-production can benefit ISD outcomes,and common knowledge,relational capital and participative decision-making between these two parties increase the effectiveness of knowledge co-production effectively.华侨大学中央高校基本科研业务费资助项目; 华侨大学哲学社会科学青年学者成长工程资助项目(13SKGC-QG14

三峡水库底栖动物群落结构特征及其与蓄水前资料的比较

为了解三峡水库在蓄水后底栖动物的群落结构特征,探索水文情势改变对底栖动物群落结构的影响,于2012年8月、11月及2013年4月对三峡水库的秭归、巫山、云阳、忠县和木洞五个断面底栖动物的群落结构进行了调查分析。结果表明：（1）共记录底栖动物43个属种,木洞种类最多（29种）,秭归最少（12种）。优势种为多足摇蚊（Polypedilum sp.）、前突摇蚊（Procladius sp.）、肥满仙女虫（Nais inflata）、霍甫水丝蚓（Limnodrilus hoffmeisteri）和一种钩虾（Gammaridae）;（2）在空间分布上,密度以木洞最高（8180±2740）ind./m

极端工况下采煤机行星减速机构动态仿真分析

为研究复杂煤层赋存条件下采煤机截割部行星减速机构的动态特性,建立了采煤机刚-柔耦合动态模型。对极端工况下的采煤机滚筒外负载进行了分析及动态模拟,在动态仿真分析软件Recur Dyn中进行了加载与虚拟仿真。对截割部行星减速机构中的内齿圈进行了受力分析,找到了最大等效应力位置并根据其受力情况进行了结构优化。对齿轮修形后的行星减速机构再次进行仿真,发现最大等效应力小于材料许用应力,并且齿面疲劳寿命得到了较大地提高,保证了采煤机可靠工作,为齿轮动力学研究提供了重要参考

Methotrexate intercalated into layered double hydroxides via ion exchange method and the corresponding bioassay explore

研究了不同水热温度下合成的层状双金属氢氧化物(lAyErEd dOublE HydrOXIdES,ldHS)对离子交换法制备的MTX/ldHS纳米复合物的影响.并利用透射电镜(TEM)、X-射线衍射(Xrd)、MTT等手段,对纳米复合物的结构及载药量、控释-缓释性、生物细胞活性母体等性质进行了系统研究.结果表明,不同ldHS母体对离子交换后复合物的形貌和性质起着至关重要的作用.在磷酸缓冲液中考察了MTX/ldHS纳米复合物的药物控释性能并进行了动力学拟合,结果表明,采用离子交换法制备MTX/ldHS纳米复合物的释药过程是fICk扩散控制的离子交换和粒内扩散过程.最后,采用MTT法探究了MTX/ldHS纳米复合物对肺癌细胞A549增殖的抑制作用,结果表明,复合物较纯的MTX具有更好的抑制癌细胞增殖的作用.In this paper, the intercalation of methotrexate(MTX) into layered double hydroxides(LDHs) interlayer by ion-exchange method has been studied.In order to obtain hexagonal and stable MTX/LDHs hybrids, the effect of different pristine LDHs hydrothermally synthesized at different temperatures(80, 100, 120 and 150 °C) has been examined carefully.The hybrids were then characterized by X-ray diffraction(XRD), transmission electron micrograph(TEM) and UV-visible diffuse spectroscopy(UV-Vis).The results indicate that the properties of pristine LDHs have great effect on those of MTX/LDHs nanohybrids, i.e., the morphology of MTX/LDHs will inherit that of pristine LDHs and the size of the samples increases with increasing of diameters of pristine LDHs.The characterizations also indicate that pristine LDHs synthesized at 150 °C could not transform into MTX/LDHs hybrids through ion-exchange process, but other pristine LDHs can do.And the resulting MTX/LDHs hybrids display hexagonal plate morphology.Then in vitro release behavior of the drugs from MTX/LDHs in p H 7.4 phosphate buffered saline(PBS) was observed, and three kinetics models were chosen to simulate the release kinetics of the drugs from LDHs.The release process of MTX/LDHs nanohybrids belongs to multi phase diffusion process via ion exchange.Moreover, the anticancer efficacy of both MTX and MTX/LDHs hybrids were also estimated in vitro by the bioassay such as MTT assay with the human lung cancers(A549).According to the cell-line tests, LDHs itself does not exhibit acute cytotoxic within the studied concentration, and the anticancer efficacy tests for the MTX/ LDHs hybrids turn out to be more effective in cell suppression compared to the MTX itself.All studies indicate that pristine LDHs synthesized from 120 °C seems suitable to be precursors for ion-exchange method, and the resulting MTX/LDHs hybrids have the highest drug-loading capacity and the most effective in cell suppression in all the samples.国家自然科学基金(21073093); 深圳市战略性新兴产业发展专项(JCYJ20120618155457353)资

Research on Daily Stress Detection Based on Wearable Device

现代生活普遍压力较大,容易引起消极痛苦的应激,导致不良情绪甚至滋生各类慢性病。心理专家需要了解个体的压力状态,从而开展对应性心理疏导和治疗。传统心理学自评法存在一定的主观性;基于生理多导仪的压力状态评估法,受设备体积所限无法用于日常压力状态评估。针对上述问题,该文采用可穿戴式传感设备实时采集个体生理信号,利用心理和生理的伴生关系,对个体的心理压力进行长期实时评估。同时通过蒙特利尔影像应激实验（MIST）诱发出被试平静、轻微及高度压力3种压力状态,此实验范式同时包含认知负荷精神压力因素与社会评价心理压力因素,与日常真实生活更为接近。该文共采集39名健康被试的实验数据,通过对数据的特征值提取等预处理,结合随机森林算法对最优特征子集进行选择,采用支持向量机（SVM）分类算法对3种压力状态进行分类预测。实验结果表明,通过随机森林特征选择优化后的SVM分类,与通用的单一SVM分类算法相比,具有更好的分类识别效果,对3种压力状态的分类准确率可从78%提高至84%

Pool Boiling Heat Transfer in Microgravity

The pool boiling heat transfer of FC-72 on a plain plate with a heating area of 15*15 mm2 in different pressure and subcooling has been studied experimentally both in normal gravity on the ground and in microgravity aboard the Chinese recoverable satellite SJ-8. A quasi-steady heating method is adopted, in which the heating voltage is controlled as an exponential function with time. Three modes of heat transfer, namely single-phase natural convection, nucleate boiling, and transition boiling, are observed, while the nucleate pool boiling are the major subject for discussion in the present paper. In normal gravity, the present data is compared with those obtained by other researchers, and a satisfactory agreement is evident and warrants reasonable confidence in the data. Compared with terrestrial experiments, the boiling curves in microgravity are considerably gentle, and CHF is no more than 40% of that in terrestrial condition. In microgravity, influences on boiling curves of the pressure and subcooling are similar with those in normal gravity, namely that the heat transfer coefficient and CHF will increase with subcooling for the same pressure, and that they will also increase with pressure for the same subcooling. Keywords: microgravity, pool boiling, subcooling, plate heate

磁性活性炭的制备与表征

探讨了负压浸渍法制备磁性活性炭的浸渍条件,浸渍溶液为油酸修饰的Fe3O4磁性凝胶均匀分散在正己烷溶剂中形成的磁性溶液. 通过对油酸修饰的磁性凝胶进行差热、热重和微热容分析确立了浸渍产物的热处理条件,考察了磁性溶液浓度、浸渍时间、浸渍温度对浸渍产物的影响,并采用X射线衍射对磁性活性炭的组份和结构进行了表征,采用磁强计测定了磁性活性炭的磁性能,用比表面、孔容测试技术比较了活性炭和磁性活性炭的比表面、孔体积和孔分布