Impinging blood droplets on different wettable surfaces: Impact phenomena,contact line motion,post-impact oscillation and dried stains

Understanding the underlying hydrodynamics of impinging blood droplets and finding out the physical parameters determining the bloodstain characteristics are of great importance in blood related forensic investigations. In this work, the impact of non-Newtonian blood droplets on solid surfaces ranging from lyophilic to superlyophobic was systematically investigated and compared to that of Newtonian droplets with a similar dynamic shear viscosity. We show that impinging blood droplets behave as low-viscosity Newtonian droplets in the short-time spreading, which is dominated by capillary and inertial forces, but their non-Newtonian viscoelasticity would notably affect the droplet retraction and post-impact oscillation occurring in large timescales. Whereas the strong liquid–solid adhesion and the non-Newtonian elongational viscosity hinder droplet recoiling and thus alter the impact phenomena on lyophobic and superlyophobic surfaces, the shear and elongational viscosities are coupled to result in higher damping coefficients of oscillating blood droplets after deposition, in comparison to that of impinging Newtonian droplets. The size of the dried bloodstain was found to be different from both the maximum spreading radius of the droplet that can reach during impact and the final radius of the deposited droplet after oscillation, and their correlations are highly dependent on the impact velocity and surface wettability. Moreover, the morphologic characteristics of the bloodstains would also be changed by varying either the impact velocity or the surface wettability. We envision that these findings can not only find applications in the bloodstain pattern analysis, but also provide useful information for medical diagnosis based on blood droplet test.     

论科学发展与社会和谐的良性互动

科学发展与社会和谐不仅在理论上是内在统一、不可分割的,而且在实践中也是相互促进、相辅相成的。党的十七大报告将科学发展和社会和谐在中国特色社会主义的伟大旗帜下有机地结合在一起,这就说明,发展中国特色社会主义,必须以推动科学发展促进社会和谐,也必须以促进社会和谐推动科学发展。着力实现科学发展与社会和谐的良性互动,必将使两者在进一步相辅相成、相互促进的过程中,共同推动中国特色社会主义建设。     

从众行为的心理探析

从众行为是人类社会普遍存在的一种现象,从众行为本身没有好坏之分。从社会学角度来说,一个社会需要有共同的语言、共同的价值观和较为一致的行为方式,这样才有利于社会功能的执行及社会文化的延续。但是不分析实际情况一味地盲从有时会给社会或个人造成不可挽回的损失。从众的原因是多方面的,从众行为具有正负效应。人们应当减少盲目从众,遇事要理性思考。     

令人不适的法医影像对司法心证的影响探微

司法人员在审查案卷时,可能由于一些令人不适的法医影像而影响其客观、公正地履行职责。在现实中法医影像制作的不规范状况扩大了这种负面影响。而对这种负面影响的制约有赖于相应法律规范和证据规则的制定、制作人观念和态度的转变、制作方式的规范,以及司法人员相应素质的提高。     

我国环境影响评价法律制度的不足及完善

2003年9月1日,《中华人民共和国环境影响评价法》正式颁布实施,该法规除对建设项目要进行环境影响评价外,同时要求对有关规划进行环境影响评价,这标志着我国环境与资源立法步入了一个新的阶段——从决策的源头来防止环境污染和生态破坏。随着经济的快速发展,其暴露出来的问题越来越多,尤其在环境影响评价的范围、公众的参与以及法律责任的承担等方面。所以,我国环境影响评价相关法律需要在适当的时机对评价的范围、公众参与等相关规定进行修改,以此来保障经济发展的高质量。     

气候变化对东南亚经济的影响

气候变化成为国际社会关注的重点,各权威机构及学者纷纷研究气候变化及其对经济的影响。本文以斯特恩评论的框架,结合有关研究资料分析东南亚的气候变化,包括气温、降雨量、极端气候事件和海平面的变化及趋势,评介这些气候变化对东南亚经济,包括对水资源、农业、林业、沿海及海洋资源和人类健康等5个方面的影响及发展趋势。     

基于重组质粒制备STR分型阳性参照物

目的基于重组质粒制备可用于校准法医STR分型的阳性参照物。方法以常用阳性参照物9948人类基因组DNA STR分型为依据,基于重组质粒构建包含CSF1PO、D7S820、TH01等40个常染色体位点,DYS391、DYS522、DYS385a/b等22个Y染色体位点以及性别判定基因座Amelogenin的STR分型阳性参照物。将重组质粒定量、稀释后等比例混合,分别应用于DNATyper~?19、DNATyper~?24、DNATyper~?Y、Amp F?STR~?Identifiler~?Plus以及Power Plex~?18D System五种扩增试剂盒。结果阳性参照物中各重组质粒浓度为0.01pg/μL~0.001pg/μL;应用于Amp F?STR~?Identifiler~?Plus PCR扩增试剂盒,基于重组质粒制备的阳性参照物与人类基因组DNA扩增检测结果差异较小;将此阳性参照物分别应用于不同公司、不同STR基因座的四种STR扩增试剂盒,电泳检测图谱显示各基因座基因型完整,分型正确,峰高相当,基因座间均衡性良好。结论基于重组质粒制备STR分型阳性参照物,是一种可以替代细胞系制备阳性参照物的方法,具有一定的参考价值。基于此方法制备的阳性参照物可适用于市面上常用的STR检验试剂盒,普适性较强,对法医DNA分型检测有一定的实用价值。     

圆明园湖底防渗工程公众听证会的法律性质研究

《环境保护行政许可听证暂行办法》规定了环境行政许可听证制度。《环境影响评价法》规定了“专项规划编制环境影响报告书听证”和“建设项目编制环境影响报告书听证会”两类制度。另外,在我国还有环境行政处罚听证制度。圆明园湖底防渗工程公众听证会并非上述意义上的“听证”,而是类似于英国“非法定听证”的一类新型听证。现阶段立法应规定,该类听证可以参照适用《暂行办法》,予以必要的立法规制。     

若干经济政策对我国职工队伍的影响

改革开放以来经济政策的主流是好的。但是,若干经济政策的失当,或经济政策是好的,由于执行中的失误,对我国职工队伍造成了一定的冲击和影响。这种影响的实质导致了劳动关系的失衡。而不均衡的劳动关系对和谐社会的构建产生的是负面影响,不利于社会的稳定和经济的发展。     

Fabrication of compound nonwoven materials for soft body armor

The primary objective of body armor research is the development of low-cost, lightweight, wearable garments that effectively resist ballistic impact. This study introduces a material intended to reduce nonpenetration trauma by absorbing energy from ballistic impacts. Layers of web were made by low-melting point polyester (LMPET) on unaligned fibers of high-strength polyamide 6 (HSPA6). A compound nonwoven fabric was made by laying high-strength Vectran filaments between two layers of HSPA6-LMPET web. The new fabric underwent needle punching and thermal bonding to form a composite sandwich structure. The new fabric was subjected to a falling weight impact test and a ballistic impact test. The results indicated that the material with the new design reduced maximum indentation depth by 8%. Furthermore, soft body armor made from the material with the new design would cost less to produce and would weigh 22.5% less than conventional soft body armor.