变异新冠病毒考验南非的治理能力

自1994年新南非成立以来,外界对执政党非国大的国家治理能力不乏质疑和诟病。2018年,西里尔·拉马福萨当选总统,其给非国大和南非政府的外部形象带来了较大改观。新冠肺炎疫情暴发后,拉马福萨政府初始的应对较为果断。不过,随着变异新冠病毒出现以及由此导致的疫情反复,加上遭遇严重的经济低迷,南非的国家治理能力面临着比预期更大、更久的考验。     

冰草和根茎冰草变异式样的初步研究

对冰草和根茎冰草进行了定性和定量分析,结果表明:这两种植物在颖和外稃被毛的性状上存在4种类型,是一多态现象。此外,冰草的某些个体在花序的性状上还具有反映祖先征状的畸形现象。同时还分析了根茎冰草某些个体在花序性状上的变异,认为这与根茎冰草的无性繁育系统密切相关。定量分析的结果表明:这两种植物在花序长、花序宽、芒长和小穗长等性状上的变异与其生境密切相关,是一种生态梯度变异。     

高层框架结构楼房定向倾倒的力学模型及强度计算

本文对高层框架结构楼房定向倾倒过程中的一个特殊环节，大胆一提出了斜形悬臂梁模型；推出了立柱上最大应力的位置和计算公式；为该类楼房定向爆破的设计提供了一项理论依据。     

能不能"事先"防毒?

几年前曾造成巨大灾害的“CIH”病毒前段时间又在网上传播,不同的是,该病毒在一些方面产生了“变异”,而成为一种“新CIH”病毒,威胁的还是连接到网上的电脑安全。类似的“变异”病毒还有很多,总是让人防不胜防。     

一种无定向导线计算方法

从已知起始点先以任意起始角及各观测值,推算至最末点,经投影修正后再反投影改正各导线边,以及拟合推算最末点至已知起算闭合点,反算得任意起始角值改正,达到无定向导线解求目标,利用小型计算器编程实现另一种非传统的数学方法计算无定向导线。     

采用定向钻机进行管道穿越大型河流的工程地质问题

分析了影响定向钻穿越大型河流施工的因素，指出工程地质条件在穿越设计和制定施工方案时具有决定性作用，系统地进行工程地质勘察是非常必要的。并针对这类特殊工程，提出了勘察工作的具体内容和方法。     

Enhancing the quality metric of protein microarray image

The novel method of improving the quality metric of protein microarray image presented in this paper reduces impulse noise by using an adaptive median filter that employs the switching scheme based on local statistics characters; and achieves the impulse detection by using the difference between the standard deviation of the pixels within the filter window and the current pixel of concern. It also uses a top-hat filter to correct the background variation. In order to decrease time consumption, the top-hat filter core is cross structure. The experimental results showed that, for a protein microarray image contaminated by impulse noise and with slow background variation, the new method can significantly increase the signal-to-noise ratio, correct the trends in the background, and enhance the flatness of the background and the consistency of the signal intensity.     

"核心期刊"的功能变异

“核心期刊“的正常功能是优化信息资源、提供便捷的检索途径，以及对期刊业的示范和导向作用。核心期刊的功能变异，突出表现在由信息源(或信息检索途径)变成了评价尺度。核心期刊功能的变异及被滥用，严重干扰了期刊界的有序竞争，浪费了宝贵的学术资源，助长了不良学风和学术腐败。     

Structure characterization of melt drawn polyethylene ultrathin films

Highly oriented ultrathin polyethylene (PE) films were prepared by a melt-draw technique. Transmission electron microscopy study on the obtained ultrathin films indicates that the melt drawn PE thin films consist of highly oriented edge-on lamellae aligned perpendicular to the drawing direction. Electron diffraction confirms that the PE chains in crystal-line phase are highly oriented in film plane along the drawing direction, while only a random orientation of the crystallographic a-and b-axes can be described through electron diffraction. The IR results on the melt-drawn ultrathin PE films demonstrate that the PE molecular chains in both crystalline and amorphous phases of the melt drawn thin films are well oriented along the drawing direction. Moreover, the IR results indicate that in the crystalline phase, the crystallographic b-axis tend to lie in the thin film plane, while in the amorphous phase, the skeleton plane of some local chains prefers to parallel the film plane. The alignment of b-axis of PE crystals in ultrathin films originates from the fact that the b-axis is the fastest growth direction of the PE crystals.