各向同性介质与单轴晶体界面上e光波法线的折射

根据光的电矢量满足的边条件，对各向同性介质与单轴晶体界面上e光波法线的折射进行了具体的讨论，得到了确定e光波法线在单轴晶体中传播方向的公式，并对几种特殊情况进行了具体讨论。指出了由所得结果可以确定e光光线的行进方向。     

含苯甲醚基团的高分子液晶的合成及表征

本文讨论了侧链含有亚甲氧基连接基高分子液晶的合成及表征．用酚类与苯甲基氯制备了六种单体，用硅氢加成法合成了高分子液晶．六种单体为：4-(4—烯丙氧基苯甲氧基)联苯(M1)，4’—甲氧苯基4—烯丙氧基苯甲醚(M2)，4’—甲苯基—4—烯丙氧基苯甲醚(M3)，苯基4—烯丙氧基苯甲醚(M4)，4—(4-烯丙氧基苯甲氧基)4’—甲氧基联苯(M5)，4—(4—甲氧基苯甲氧基)-4’—烯丙氧基联苯(M6)．用偏光显微镜和DSC测定了单体和高分子液晶的相转变温度和介晶范围，单体M5和M6显示较好的液晶性，聚合物PM1、PM5、PM6、P(M2—M5)和P(M2—M6)显示出较好的液晶性，共聚物液晶比其它高分子液晶的介晶范围宽．     

Decoration of disclinations by solidification-induced band texture and focal-conic texture for a low-molar-mass liquid crystal

Two decoration techniques, solidification-induced band texture decora tion and focal-conictexture decoration, have been established to exhibit the director field of disclinations in a low-molar-mass methacrylate liquid crystal. The disclinations with strength s = 1/2 and s = ±1 are observed by the two decor ation methods. For the solidification-induced band texture decoration, the molecular orientation is perpendicular to the direction of the band. While for focal- conictexture decoration, it has been proved by the results of IR dichroism that the direction of the director is parallel to the direction of the focal-conic. Therefore, the sketch map of the molecular director filed can be mapped according to the morphological pattern of the solidification-induced band textureor focal-conic texture.     

一种数字密码电路

介绍一种以 JK 触发器为主要组成部分的数字密码电路,并着重对它的工作原理和功能的实现进行了论述,从而阐明了此电路的实用性和可取性。     

一种新型空间电压矢量调制方式的研究

通过对传统的空间电压矢量调制方式的研究,提出了一种改进型的空间电压矢量调制方式,并给出了此改进型SVPWM调制方法下的各矢量作用时间的推导.相对传统的调制方式,此方法能够同时满足变频器输出在高频段和低频段的需要,适应了不同应用场合下的要求.实验结果证明本方法切实可行,具有一定的推广价值.     

双DC-DC变换器在爆闪式警示信号灯上的应用

本文探讨利用双DC-DC变换器去解决单级DC-DC变换器在宽电压范围工作时开关效率降低,开关器件不能正常工作,甚至损坏的问题。在现有信号灯的基础上,设计出一种寿命长、适应宽电压范围、功能齐全,便于生产、管理、使用、维修的爆闪式警示信号灯。     

炭黑／结晶性含氟树脂合金在自控温加热电缆中应用

选择了结晶性含氟树脂添加改性剂为树脂基体，与炭黑制居复合导电体系。通过这个对体系不同条件下ＰＴＣ特性的研究，对其配方与加工工艺进行优化。并利用扫描电镜，Ｘ射线衍射，ＤＳＣ等分析测试手段，对体系的各种开矿结构进行了研究，阐明了该导电复合体系的形态结构与性能的关系。     

6-异丙基-3-甲酰基色酮双杂环衍生物的合成

以6-异丙基-3-甲酰基色酮为原料分别与胺、3-乙酰基香豆素以及乙酰甘氨酸反应,得到了5个未见报道的含3-杂环取代的色酮或色满酮类双杂环化合物,产率46%~73%。通过元素分析、MS、IR、1H NMR对其结构进行了确认。同时用X射线单晶衍射法测定了2-乙氧基-6-异丙基-3-(吗啉亚甲基)-4-色酮的晶体结构,晶体属单斜晶系,P21/n空间群,晶胞参数为:a=1.338 5(3)nm,b=0.868 38(17)nm,c=1.668 4(3)nm,β=108.59(3)°,V=1.838 0(6)nm3,Z=4,Dx=1.190 Mg/m3,μ=0.079 mm-1,F(000)=712,R=0.069 2,wR=0.138 7。     

Microstructure transition of Al-Cu eutectic alloy during containerless rapid solidification

Droplets of Al-32.7%Cu eutectic alloy were rapidly solidified during containerless processing in a 3 m drop tube. The microstructural evolution of Al-Cu eutectic alloy depends strongly on droplet size. The eutectic growth morphology changes from regular lamellar eutectic to a kind of anomalous eutectic with the decrease in droplet size. This microstructural transition was analyzed within the current theories of eutectic growth. The results indicate that there exists a critical velocity for eutectic growth beyond which anomalous eutectic appears. The coupled zone of the Al-Cu eutectic alloy system has been calculated on the basis of the Trivedi-Magnin-Kurz(TMK) eutectic growth and the Lipton-Kurz-Trivedi(LKT)/Boettinger-Coriell-Trivedi(BCT) dendrite growth models, which provides a further interpretation for the morphological transition.