DNA/lipid complex organogel with shape‐memory behavior

DNA and amphiphilic N,N,N‐trimethyl‐N‐hexadecylammonium bromide (THAB) were stoichiometrically mixed together to produce a DNA–lipid complex, which was dissolved in dimethyl sulfoxide (DMSO) at 65°C and then crosslinked with isophorone diisocyanate (IPDI). The obtained organogel swelled reversibly in DMSO, responding to the variation of temperature. Interestingly, we observed that the gel exhibited a temperature‐dependent shape‐memory behavior. Above 65°C, whatever the shape the gel was deformed to, it could retain the new shape as the temperature was decreased to room temperature, while, when the gel was heated to 65°C again, it could recover its initial shape. The shape‐memory characteristic is supposedly originated from the transition between the close‐packed and the destroyed DNA/lipid conformation. The elastic urethane crosslinking bonds between base‐pair sites act as a fixing phase. The gel holds promise in its application as a gentle actuator. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 259–263, 2002     

贵溪冶炼厂闪速炉炉体第二次改造

介绍贵冶闪速炉炉体两次改造 ,炉体冷却元件的设置及设计特点 ,阐明了设置冷却元件必要性及使用的实际效果。     

双极型静电感应晶体管开关时间的测量与分析

从理论和实验两方面对静电感应晶体管（ＢＳＩＴ）的开关时间进行了分析和测量，提出了简单的分析方法，将影响ＢＳＩＴ开关时间的各个因素归结为结构因子和材料因子，从而简化了分析影响ＢＳＩＴ开关时间的因素，对于ＢＳＩＴ的实际工艺，结构设计有指导意义。     

Assessment of melt cleanliness in A356.2 aluminium casting alloy using the porous disc filtration apparatus technique: Part II Inclusion analysis

The data obtained on inclusion types and concentrations has been analysed in the present part in terms of their effect on filtration time and fluidity (measured by the length of solidified metal in quartz tubes). The dross, i.e., the oxide layer that formed on the surface of the molten metal, was carefully collected and its mass determined; then it was examined in a scanning electron microscope equipped with an energy-dispersive X-ray system. The results show that inclusions are not the only parameter to be considered. More importantly, it is Al2O3 (films or particles), which seems to be the deciding factor. It is found, however, that it is quite difficult to separate the individual role of each parameter using the porous disc filtration apparatus (PoDFA) technique, i.e., sampling, without disturbing the molten metal. Sampling would introduce undesirable oxides into the PoDFA crucible, resulting in an artificial increase in the filtration time. Increasing the holding periods of the molten metal increases the quantity of dross. In all cases, the skimmed dross is wet, i.e., it contains an appreciable amount of molten metal. The main types of oxides in the dross are MgO, MgAl2O4, Al4C3 and Al2O3. This revised version was published online in November 2006 with corrections to the Cover Date.     

钽酸锂晶体宽带滤波器

本文简要介绍钽酸锂晶体及器件的一些特性,对用该材料制作的21.4MHz宽带滤波器的设计、制作和测试结果作了较详细的介绍,滤波器的带宽达225kHz,矩形系数(BW_(?0dB)/BW_(3dB)为2.66,带外衰减在50dB以上。该材料在做宽带滤波器和压控振荡器方面具有优越性。     

杂质元素对金属镝压缩强度的影响

研究了金属镝中所含Ｓｉ、Ｃａ、Ｆｅ和Ｏ４种杂质元素对其压缩力学性能的影响。结果表明，Ｓｉ元素和Ｏ元素含量的增加会降低镝的压缩强度，与此同时，其塑性也有明显地降低。金属镝中所含Ｃａ元素和Ｆｅ元素对其压缩强度的基本没有影响。     

专用集成电路CAT技术的进展

本文简单地回顾了提高VLSI测试效率所采用的一些手段,讨论了在ASIC测试问题研究中出现的一些新观点、新方法、新动向,以及所取得的成果。在此基础上,文章阐明了ASIC测试技术的发展方向,并着重论述了可望在未来得到发展的,针对ASIC的功能测试方法。     

再造鼓形膨胀器

介绍了本钢不停产安装再造煤气管道鼓形膨胀器的实践，并对制造、安装方法进行了叙述，特别是在结构上采用了独特的构槽密封焊缝和完整的安装程序，保证了实施的安全。     

求通信网生存能力的一种分裂二叉树算法

本文研究了布尔代数方法在通信网生存能力分析中的应用，提出了一种求布尔代数式不交化变换的分裂二叉树算法，与现有的同类算法相比，该算法具有结构清晰、执行效率高、易于实现等优点。     

日本水土保持见闻

通过考察日本的水土保持工作,文中在简明介绍日本水土保持工作的基础上,尤其着重介绍了日本的庭园水土保持,小流域的综合治理,治山绿化工程,水土保持科学研究和滑坡、泥石流防治工程等技术措施和方法。并提出了一些有益的建议;他们的经验有许多值得我们借鉴。