“和差化积”在抽象矩阵运算中的应用

抽象矩阵的运算是线性代数考研题中常见的一种题型,但由于抽象矩阵的具体元素未知,所以只能综合运用矩阵的性质来计算。在矩阵乘积的运算中,|AB|=|A||B|,(AB)-1=B-1A-1等性质可以大大简化运算。但在矩阵的和差运算中,由于|A B||A||B|,(A B)-1 A-1 B-1,因此必须把和差转化为乘积,即"和差化积",从两个方面说明"和差化积"的应用。     

基于CVM的建筑废弃物回收利用非市场价值评估

本研究以建筑废弃物为研究对象,通过问卷形式调查绵阳市居民对建筑废弃物回收利用非市场价值的认知以及支付意愿,在此基础上采用条件价值法(contingent value method,CVM)对建筑废弃物回收利用的非市场价值进行核算和评估,并分析影响居民支付意愿的因素.结果显示:2015年绵阳建筑废弃物回收利用非市场价值为8.29亿元,占2015年绵阳市建筑业总产值的2.19%;城市,农村居民的平均支付意愿分别为584.88元/(户每年)和208.08元/(户每年),分别占家庭年平均收入的0.91%和0.55%.由此可知,建筑废弃物回收利用非市场价值巨大,但平均支付意愿在家庭年平均收入中所占比例较低,说明居民对建筑废弃物回收利用非市场价值支付意愿还很低.研究发现,居民对建筑废弃物价值的认知程度和政府对建筑废弃物回收利用经费的透明化管理是影响城乡居民支付意愿的主要因素.因此,加强建筑废弃物回收利用宣传教育和经费透明化管理,是提高居民支付意愿,改善建筑废弃物回收利用现状的有效手段.     

跨境电商人才校企协同育人模式探析

针对跨境电商飞速发展导致人才缺口持续加大的问题,提出跨境电商人才需要具备外语交流、外贸实务、网络技术、国际物流和跨文化沟通等五个方面的素质,认为校企协同育人应是跨境电商人才培养的首选模式。构建了校企合作指导跨境电商实习、依托企业以赛促练、学生代理企业产品和共建跨境电商人才培养的课程体系。     

基于集对分析的城市供水管网漏损预测及降漏研究

为了降低管网漏损水平,保障城市供水安全性和可靠性,以云南省某城市典型供水片区作为研究对象,运用集对分析漏损预测模型（SPA LF）,从供水管网漏点数和漏点率两个方面分析了不同管材漏损的实际情况,预测未来不同管材的漏损趋势。该研究能够提高供水企业主动检漏水平与供水安全可靠性,降低管网漏损率与供水成本。     

降低OFDM系统复杂度的改进SLM算法

为了降低正交频分复用(OFDM)系统中传统选择性映射(SLM)算法的计算复杂度,提高系统的频谱利用效率,提出了基于转换向量(conversion vectors)与随机筛选序列(random selection sequences)相结合的选择性映射(CR-SLM)算法.CR-SLM算法是将原始信号序列等分,然后对于数据序列的前半部分与转换向量相乘进行循环卷积,对于数据序列后半部分进行随机序列筛选,筛选出最优序列.最后将两部分输出序列合并生成候选序列,筛选出最优序列进行传输.仿真结果表明:CR-SLM算法在保持与传统SLM 算法PAPR性能相近的情况下,较大幅度降低了计算复杂度.     

人事选拔情景判断测验作假的实证研究

选用情境差异范式,以情景判断测验为实验材料,以140名大学生为被试,探讨警告以及标准识别能力对考生作假的影响.结果表明,情景判断测验中存在作假现象.标准识别能力显著正向预测作假.警告与标准识别能力的交互作用可预测作假,对于标准识别能力较高的考生,警告不但不能减少作假,反而助长作假;对于标准识别能力较低的考生,警告无明显作用.     

A new species of Didogobius (Teleostei: Gobiidae) from the Adriatic Sea

Didogobius schlieweni sp. nov. is described from a single specimen collected among pebbles in shallow water at Unije island, near Cres, in the northern Adriatic Sea. The holotype has vivid dark and pale patterning, and is assigned to Didogobius on the basis of head neuromast patterns and meristic features. Diagnostic values of the latter are D2 I/12, A I/11, P 17, and LL 55–56. A key to species of the Chromogobius and Didogobius complex is provided.     

Butterflies (Lepidoptera: Papilionoidea) of Mount Kilimanjaro: Nymphalidae subfamilies Libytheinae,Danainae, Satyrinae and Charaxinae

This paper, which presents an annotated checklist of the ‘lower Nymphalidae’ (Libytheinae, Danainae, Satyrinae, Charaxinae), is the fourth in a series on the butterfly fauna of Mount Kilimanjaro. Four genera of lower Nymphalidae (Danaus, Amauris, Bicyclus, Charaxes), with a total of 11 included species, are known or believed to occur within the main forest zone, from c. 1800 to 2800 m. Of these, only three species of Charaxes (Charaxes berkeleyi, Charaxes ansorgei, Charaxes xiphares) may be restricted locally to this primary forest. The lower slopes fauna, below 1800 m, is considerably richer, with a total of 11 genera and 41 species listed (8 species of which extend into the forest zone). Possible additional species, dubious earlier records, problems with African subspecies of Danaus chrysippus, a need for more work on certain Satyrinae, and classification of the genus Charaxes are discussed. An identification key to the subfamilies of Nymphalidae, and the 19 genera of Libytheinae, Danainae, Satyrinae, Charaxinae that occur in Tanzania, together with a key to the adults of all the species of these four subfamilies considered to occur or have occurred on Kilimanjaro, with 206 colour images, are included as online Supplementary Information.     

A new genus and species of Conchaspididae (Hemiptera: Coccoidea) from Florida,remarkable in lacking legs

A new genus of Conchaspididae, Asceloconchaspis gen. nov., is described for Asceloconchaspis milleri sp. nov., a new species from Florida, USA. Unlike other conchaspidids, the adult female and second instar of the genus lack legs. The presence of legs is one of the important, distinguishing characters at present separating the Conchaspididae from the Diaspididae. However, the new genus also possesses well-developed antennae and has multilocular disc pores on the abdomen in the adult female; these distinctly conchaspidid characters are never found in the Diaspididae. Asceloconchaspis is closely related to Fagisuga Lindinger, a monotypic genus with primitive characters described from South America on Nothofagus. A key to the four known genera of Conchaspididae is provided, and the morphology and distribution of the Conchaspididae are discussed.     

论董其昌绘画理论对汪野亭瓷板画的影响

以汪野亭山水瓷板画为研究对象,结合董其昌的绘画理论,从汪野亭山水画师古与师造化的创作历程、对以书入画创作手法的继承和＂天真幽淡＂主导下兼擅南北宗山水风格三方面入手,探求董其昌绘画理论对汪野亭山水瓷板画,尤其是其后期独创的青绿山水粉彩瓷画的异代影响,以期为汪野亭瓷板画创作研究提供另一有益角度。