中国营养学会新成果

中国营养学会由 730 0名专家组成 ,去年推出了中国人维生素和矿物质摄入的新国家标准 ,今年又公布了中国人科学补充维生素和矿物质的黄金搭档配方 :1.中国儿童、青少年急需补充———锌、维生素Ａ需要补充———钙、铁、硒、维生素Ｂ1、Ｂ2、Ｂ6、Ｃ、Ｄ和叶酸不需补充———维生素Ｅ(生育酚 )、β—胡萝卜素、铜、磷、镁等2 .中国女士急需补充———铁、维生素Ａ需要补充———叶酸、钙、锌、硒、维生素Ａ、Ｂ1、Ｂ2、Ｂ6、Ｃ、Ｅ等不需补充———维生素Ｄ(胆钙化醇 )、铜、磷、镁等3.中国中年、老年急需补充———钙、硒需要补充———铁…     

原子吸收法测定——血清中的铜、锌、铁

原子吸收法近年来已较多地应用于测定血清中的微量元素。对于血清中的铜、锌、铁等元素的测定,通常采用干法灰化或湿法消化来处理样品,也可直接用稀硝酸稀释样品。但这些办法都有缺点,干法灰化易引起元素的挥发损失,湿法消化由于加入的酸量较多而带来较高的空白,用硝酸稀释样品的办法则喜事倍数过大,影响测定的准确性,对于含量较低的元素则检测     

火焰原子吸收光谱法测定铝合金中的镁元素

本文研究了用火焰原子吸收光谱法测定铝合金中镁的含量时，酸度、干扰元素、干扰抑制剂的加入量对测定结果的影响。通过大量实验的反复验证，确定了测定铝合金中镁元素含量的最佳工作条件，并在最佳工作条件下测定5个标准试样，准确度高，从而证明了本方法的可行性。本方法测定镁的范围为：0．005％～5．00％，检测限为：0．015μg·mL^-1，特征浓度：0．07μg·mL^-1。     

应用镁金属化学还原法制备多孔Si/Si-O-C负极材料机理研究

以二乙烯基苯和聚硅氧烷为原料经先驱体转化法制备Si-O-C材料,利用镁金属在惰性气氛保护下高温还原制备多孔的Si/Si-O-C负极材料。利用X射线衍射、能谱分析、元素分析和场发射扫描电镜分析多孔Si/Si-O-C负极材料的组成、结构、形貌,从而研究利用镁金属化学还原法制备多孔Si/Si-O-C负极材料的机理。结果表明,镁金属在还原过程中生成MgO和Mg_2SiO_4等产物,经HCl洗涤后可形成多孔的Si/Si-O-C负极材料。Si/Si-O-C材料中的单质硅分布于多孔的Si-O-C相中,一定程度上可缓解Si在循环过程中产生的体积效应。利用镁金属还原Si-O-C材料制备多孔Si/Si-O-C材料是一种可行的制备方法。     

黄铜脱锌腐蚀的特征及防止措施

黄铜在机械设备制造中应用广泛,但黄铜在使用中存在脱锌腐蚀现象,弄清楚脱锌腐蚀的机理,找到防止脱锌腐蚀的措施对延长设备使用寿命具有重要意义。阐述了黄铜脱锌腐蚀的特征和影响因素,着重论述了黄铜脱锌的腐蚀机理。研究发现,在黄铜合金中加入砷、硼、稀土等元素或采用缓蚀剂可防止黄铜的脱锌腐蚀。     

警惕“隐形饥饿”

当你酒足饭饱之际，你的胃也许很饱了，但你的身体可能并没有真正吃饱，一种叫作“隐形饥饿”的现象正笼罩着你。原来，人体保持健康，不仅需要碳水化合物、脂类、蛋白质等大量营养素，还需要铁、锌、硒、碘等16种矿物元素，以及维生素A、维生素E、叶酸等13种维生素在内的必需微量营养素。但全世界有20亿人口由于缺乏这些微量营养素而导致健康受损，如果这些微量营养素长期摄入不足，     

“三线——三献”颂

这里,开门见山,出门是山,山里有山,山外还是山。这里山高谷深,群峰峭拔,苍茫雄浑。这里,古道悠悠,驼铃声声。这里,地不长草,天上无飞鸟,风吹石头跑。这里,亘古荒凉,古朴中蕴含着灵气。这里,青山列队,绿水长流,山环水绕。这里,是东方陆地上的百慕大,蕴藏着煤、铁、铜、铅、锌、石棉、磷、岩盐……有多种金属矿和非金属矿,是祖国的聚     

不同增强体镁基复合材料的阻尼性能

研究了短切碳纤维、碳化硅晶须、硼酸铝晶须为增强体的镁基复合材料在外加载荷下的阻尼性能,测量了它们的力学性能与断口特性。研究表明：增强体不同的镁基复合材料,阻尼性能不同;在所研究的几种增强体复合材料中,以短切碳纤维增强镁基复合材料的阻尼效果最好;短切碳纤维增强铁基复合材料界面对内耗有明显的影响。     

利用镁金属化学还原法制备多孔Si/Si-O-C负极材料机理研究

以二乙烯基苯和聚硅氧烷为原料经先驱体转化法制备了Si-O-C材料，利用镁金属在惰性气氛保护下高温还原制备了多孔的Si/Si-O-C负极材料。Si/Si-O-C负极材料的首次放电与充电容量分别为547.2和450.7mAh?g-1，第二次放电与充电容量分别为487.4和422.9mAh?g-1，库伦效率分别为82.3%、86.8%，材料具有较好的循环性能。利用X射线衍射(XRD)、能谱分析(EDX)、元素分析和场发射扫描电镜(FE-SEM)分析了多孔Si/Si-O-C负极材料的组成、结构、形貌，从而研究利用镁金属化学还原法制备多孔Si/Si-O-C负极材料的机理。结果表明，镁金属在还原过程中生成MgO和Mg2SiO4等产物，经HCl洗涤后可形成多孔的Si/Si-O-C负极材料。Si/Si-O-C材料中的单质硅分布于多孔的Si-O-C相中，一定程度上可缓解Si在循环过程中产生的体积效应。利用镁金属还原Si-O-C材料制备多孔Si/Si-O-C材料是一种可行的制备方法。     

12VE230ZC 型柴油机磨损监测

介绍了应用铁谱、发射光谱和配有能谱仪的电子扫描显微镜等分析技术对１２ＶＥ２３０ＺＣ型柴油机的润滑油样进行分析,从而获得磨损信息．铁谱分析能判别机器磨损工况的正常与否,并能判断引起异常磨损的原因．光谱分析通过发现指示性元素和元素浓度的异常来判断柴油机故障．对有异常磨损磨粒的谱片用电镜和能谱进行分析,有助于确定磨损的部位．     

基于扩张观测器的三维有限时间收敛导引律

为了保证视线角速率在弹目碰撞前收敛到零附近的较小邻域内从而达到准平行接近的状态,本文基于自抗扰控制的不确定性估计补偿思想,应用反演控制方法设计了一种考虑导弹自动驾驶仪二阶动态特性和目标机动的三维有限时间收敛导引律。根据有限时间收敛控制理论,严格证明了系统的有限时间收敛特性;为抑制量测噪声,将传统跟踪微分器进行改进并应用于扩张状态观测器与反演控制的设计中。仿真结果表明:在自动驾驶仪响应延迟情况下,所设计的导引律能够导引导弹在有限时间内精确地拦截高速机动目标;改进的跟踪微分器精度高、响应快;基于改进跟踪微分器的扩张观测器估计效果理想。     

READY,SET, TRACE

Tracing small arms and light weapons has been identified as an important component in reducing the illicit trafficking of weapons to regions of conflict as well as use in violent crime. At the national, regional and international levels policy makers and practitioners are working to make tracing more effective. This article outlines some of the key elements of an effective tracing regime and reviews where areas of agreement currently exist. It concludes with observations on some of the challenges facing countries as they try to implement these systems and respond to the problem of illicit arms trafficking.     

Consumer drone evolutions: trends,spaces, temporalities,threats

ABSTRACT

While the drone has become synonymous with the War on Terror, the asymmetric iconography of the battlefield is shifting. Commercially available off-the-shelf (COTS) drones are increasingly prevalent features of global battlefields, employed by non-state actors in both visualising such spaces, and the directing and inflicting of harm. As such usage increases, so too do concerns around their evolving adoption, adaptation, and potential portability into homeland spheres. While cognizant of the range of positive drone applications, it is asserted that drones nonetheless remain simultaneously bound to an inverse potential for exploitation. In examining drone risk, this article approaches the consumer drone through a series of sites and spaces through which it is technically and socially constructed. Reflecting upon industry innovation, community-driven experimentation, and evolving airspace – it calls for greater attention to the drone’s malleability, arguing that understandings of COTS drones must remain attentive to both drone potential and potential drone threat.     

Drones,spies, terrorists,and second-class citizenship in Pakistan

This essay reviews seven recent books and reports that focus upon the use of US armed drones in Pakistan's Federally Administered Tribal Areas (FATA). This essay synthesizes a historical account of the program, critically interrogates key arguments and evidence advanced by the authors, and draws attention the particular problems that confront those who live in the FATA and the second-class citizenship that the Pakistani state has bestowed upon them for reasons of domestic and foreign policy concerns. This review essay does not intend to be the final word on any of the ongoing policy debates. But it does hope to enable a wider audience to take part in these important deliberations.     

COOPERATION,SIGNALS, AND SANCTIONS

This paper uses game theory and modeling to address the role of incentive structures and information dynamics in nuclear inspections. The traditional argument is that compliant states should be willing to allow inspections to prove their innocence, while proliferating states are likely to impede inspections. This argument does not take into account the historical variation in inspection, signaling, and sanctioning behaviors. Using a game theoretic analysis and model, it is shown that the separation of proliferators from nonproliferators only occurs when the likelihood of proliferation is high and punishment costs are moderate. The model assumes that states can choose how much to cooperate with inspectors and must pay opportunity or secrecy costs when inspections are effective. The results are tested against a set of real-life cases, providing support for the claims of historical variation and the model's deductive propositions.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

Ethnicity,class, and civil war: the role of hierarchy,segmentation, and cross-cutting cleavages

Why are some countries prone to ethno-nationalist conflict, whereas others are plagued by class conflict? This is a question that has seldom been raised and rarely been examined empirically. This paper presents a social-structural theory to account for the variable incidence of these two forms of political instability. These two types of conflict result from distinct principles of group solidarity – ethnicity and class – and since each individual is simultaneously a member of an ethnic group (or many such groups) and a particular class, these two principles vary in the degree to which they are mutually exclusive or cross-cutting. The degree of economic stratification between groups and economic segmentation within them shapes the relative salience of each principle of group solidarity in any society and is associated with a characteristic form of political mobilization. In places where between-group inequalities are high, and within-group inequalities low, ethnicity should be the dominant principle of group solidarity and serve as the primary basis of group conflict. By contrast, in countries where between-group inequalities are low, and within-group inequalities high, class is more likely to serve as the dominant principle of group solidarity, and conflicts along class lines are more likely. We test these conjectures with data in over 100 countries on cross-cutting cleavages, ethnic war, and class conflict. The results are supportive of the theory, and provide evidence that how groups are stratified and segmented in societies shapes the type of civil war.