基于差值图像及肤色特征的人脸定位方法

该文提出一种用于安保监控系统中提取人脸的实用有效方法。该方法利用运动序列图像之间的差分图像，检测出运动目标区域，得到运动目标子图像，剔除大部分静止背景的干扰。随后对于图像进行肤色映射，得到二值图像，对二值图像进行水平和垂直投影，确定人脸的左右边界和上下边界，从而得到人脸的准确定位。该方法在工程上有效且计算量较少，可以达到实时需要。     

一种城市电动公交客车制动能量回馈方法

为提高汽车能源利用率,提出一种电回馈制动与机械摩擦制动相结合的城市电动公交客车制动能量回馈方法.采用可控制实现串并联实时切换的超级电容器模块作为电源,当电动公交客车驱动运行时,控制超级电容器模块串联放电提供能量;而当电动公交客车制动运行时,控制超级电容器模块并联充电回馈能量.在制动初始阶段,采用电回馈制动,电动机发电运行并提供恒制动扭矩,当电动机转速减至不能提供恒制动扭矩时,由机械制动提供制动力直至制动过程结束.仿真和试验结果证明:提出的制动能量回馈方法可实现低速制动能量回馈,具有较高的制动能量回馈效率.     

Kerr-Newman时空中带电旋转粒子的Hawking辐射

拓展Banerjee和Majhi研究黑洞Hawking辐射的方法,在保持时空中总能量、总电荷和总角动量守恒的条件下,利用新定义的Tortoise坐标变换研究带电旋转黑洞的Hawking辐射.在考虑辐射粒子对时空的反作用后,不但得到满足量子力学幺正性原理的黑洞辐射谱.而且在结果中显示,由带电旋转粒子引起的辐射谱中类似化学势的项,入射波与出射波的贡献是相等的.使人们对黑洞Hawking辐射的物理机理又有了一种新的理解.     

Exotoxin A-eEF2 complex structure indicates ADP ribosylation by ribosome mimicry

The bacteria causing diphtheria, whooping cough, cholera and other diseases secrete mono-ADP-ribosylating toxins that modify intracellular proteins. Here, we describe four structures of a catalytically active complex between a fragment of Pseudomonas aeruginosa exotoxin A (ETA) and its protein substrate, translation elongation factor 2 (eEF2). The target residue in eEF2, diphthamide (a modified histidine), spans across a cleft and faces the two phosphates and a ribose of the non-hydrolysable NAD+ analogue, betaTAD. This suggests that the diphthamide is involved in triggering NAD+ cleavage and interacting with the proposed oxacarbenium intermediate during the nucleophilic substitution reaction, explaining the requirement of diphthamide for ADP ribosylation. Diphtheria toxin may recognize eEF2 in a manner similar to ETA. Notably, the toxin-bound betaTAD phosphates mimic the phosphate backbone of two nucleotides in a conformational switch of 18S rRNA, thereby achieving universal recognition of eEF2 by ETA.     

Phylogenetic relationship and morphological evolution in the subfamily Limenitidinae （Lepidoptera： Nymphalidae）

The mitochondrial cytochrome oxidase subunit I （CO1） gene and the nuclear elongation factor 1 α（EF-1α） gene were sequenced from 29 species of Nymphalidae （Nymphalidae, Lepidoptera）. Phylogenetic trees were constructed based on the sequences determined from the 29 species and sequences of other 36 species deposited in GenBank using the neighbor-joining （NJ）, maximum likelihood （ML） and Bayesian methods with Libythea celtis （Libytheinae） as the outgroup. Our phylogenetic trees indicated four major clades. Clade A includes three subfamilies： Apaturinae, Nymphalinae, and Limenitidinae, excluding the tribe Limenitidini; Clade B includes the subfamilies Heliconiinae and the tribe Limenitidini; Clade C includes Satyrinae, Calinaginae, Charaxinae and Morphinae; and Clade D includes subfamily Danainae. Our study suggested that the tribes Pseudergolini, Biblidini, Limenitidini and Cyrestidini should be considered as subfamilies and confirmed the interspecific relationships within the subfamily Pseudergolinae, namely Amnosia ＋（Pseudergolis ＋ （Stibochiona ＋ Dichorragia））. We then mapped three morphological characters （spot of anal angle, eyespots, and process from outer margin of hind wing） onto the phylogenetic tree constructed by ML analysis using the combined sequence data. Based on this the evolutionary patterns of these morphological characters were identified, they indicated that the three characters evolved repeatedly in the family Nymphalidae.     

混合花岗岩加载细观力学特性及破裂演化规律

根据室内试验获得的岩石宏观物理力学参数及岩样切片扫描图,基于颗粒流理论和PFC程序建立混合花岗岩颗粒细观几何模型,标定模型材料细观力学参数,采用Fish语言编制加载命令流并调整相应函数,对岩石单轴和三轴压缩试验进行模拟.通过对试验与模拟应力-应变曲线、AE声发射与PFC程序中“Crack”裂纹监测成果等的综合比较研究,获得荷载作用下杏山铁矿-45 m水平混合花岗岩细观力学特性、微破裂行为以及岩石微裂隙发展与宏观破裂演化规律.通过对混合花岗岩单轴和不同围压下三轴压缩PFC模拟曲线与室内试验结果的比较可知,PFC模拟能准确地表征荷载下岩石颗粒的细观力学特性和运动学行为.     

The composition and distribution of metal clusters in the MoFe protein from a nifZ deletion strain （DJ 194） of Azotobacter vinelandii

Through the anaerobic chromatography on the columns of DEAE 52, Q-Sepharose and Sephacryl S-200, a nitrogenase MoFe protein (△nifZ Av1) was obtained from a nifZ deleted mutant of Azotobacter vinelandii (stain DJ194).The results of Western blotting after anoxic native electrophoresis and SDS-PAGE showed that △nifZ Av1 was similar to wild type MoFe protein (OP Av1) at the electrophoretic mobility, molecular weight and subunit composition. Furthermore, △nifZ Avl was also similar to OP Av1 at the molybdenum content, EPR signal (g≈4.3, 3.65 and 2.01), and the molar extinction coefficient (△ε) of circular dichroism (CD)at 660 nm region. All of these indicated that, besides having the same α2β2 composition as OP Av1, the △nifZ Av1 also contained equal amount of reductive FeMoco in the spin state of S=3/2 to OP Av1. However, the iron content and substrate (C2H2, H^ and N2)-reduction activity of △nifZ Av1 were 74% and 46%-50% of those of OP Av1, respectively. Furthermore, the △ε at around 450 nm, which reflects P-cluster in Av1, was obviously lower than that of OP Av1. It suggested that the difference between △nifZ Avl and OP Av1 resulted from P-cluster rather than FeMoco, and from the half number of P-cluster in △nifZ Av1, but the composition or redoxstate of P-cluster in △nifZ Av1 were not changed. Thus it could propose that △nifZ Av1 is composed of two different αβsubunit pairs. One is a FeMoco-and P-cluster-containing pair, and the other is a P-cluster-deficient but FeMoco-containing pair. Since the deletion of nifZ gene leads to the deficiency of only one of two P-clusters in a α2β2 tetramer, the assembly of P-cluster may not simply depend on one gene product, and so a possible mechanism of NifZ is supposed here.     

服务业顾客满意度指数模型

在欧美顾客满意度指数模型的基础上,提出了一种简化的能在不同的服务行业中广泛使用的比较服务质量的顾客满意度指数模型。用SAS的CALIS程序对基于该模型的调查数据进行检验表明,模型的拟和性能良好。利用CALIS统计过程可以容易地得到的感知质量和感知价值(模型中的隐变量)与顾客满意度之间的路径系数,有助于服务企业了解顾客的偏好,以供改进服务提供策略的参考。     

基于响应面分析法的草鱼蛋白酶解工艺

应用响应面分析法对草鱼蛋白两段酶解的条件分别进行优化,第一段酶解复合使用胰酶／风味蛋白酶（质量比为4：1）,以蛋白质利用率为响应值;第二段酶解用木瓜蛋白酶,以肽得率为响应值．最终确定第一段酶解的最优条件为：酶（E）与底物（S）的质量比为0．3：100,温度为53℃,时间为5．90h;第二段酶解的最优条件为：E与S的质量比为0．12：100,温度为60℃,时间为5．60h．利用凝胶色谱测得最优条件下制备酶解液组分的相对分子质量范围介于714～8790之间,酶解液中肽含量超过50％（质量分数）,与响应面模型所预测的肽得率（52．55％）相吻合．     

高产5-氨基乙酰丙酸光合细菌株hemA基因的克隆与序列分析

对从不同生态环境中分离得到的20株光合细菌,进行5-氨基乙酰丙酸(5-ALA)的产量检测,结果显示一株分离自广州市云溪公园池塘底泥的菌株R5,其5-ALA 产量最高,达4.92 mg/L.根据GenBank上公布的5-氨基乙酰丙酸合成酶hemA基因序列,设计引物进行hemA基因的克隆.结果表明,菌株R5的hemA基因序列长1 230 bp, 不含HindⅢ酶切位点,G C为64.68%,编码一个409个氨基酸的酶蛋白,分子质量为44.9 ku,与Rhodopseudomonas palustris KUGB306菌株的hemA基因序列相似性为98.6%,氨基酸序列相似性为100%.系统发生树显示,菌株R5与Rhodopseudomonas palustris处在一个分支,显示菌株R5可能是Rhodopseudomonas palustris,这与微生物鉴定实验的结果一致.本研究克隆的高产5-氨基乙酰丙酸菌株的hemA基因,为后期获取高产5-ALA的基因工程菌打下基础.