SYNTHESIS AND CHARACTERIZATION OF PALLADIUM COORDINATING IMINE SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES

New thermotropic chloro-bridged dinuclear palladium coordinating imine side chain liquid crystalline polysiloxanes have been synthesized. Their mesomorphic properties have been investigated by DSC, X-ray diffraction and polarizing microscopy. The polymeric complexes show nematicdiscotic (Nd) mesophase. It is found that the temperature range of liquid crystalline state of chloro- bridged polymeric complexes is much wider than that of acetato- bridged ones and imine side chain polysiloxane. This indicates that the disc-like chloro-bridged palladium complexing units play a role as mesogen in mesophase.     

TEMPERATURE DEPENDENCE OF THE FLUORESCENCE SPECTRA OF LADDERLIKE POLYPHENYLSILSESQUIOXANE AND LADDERLIKE 1,4-PHENYLENE-BRIDGED POLYVINYLSILOXANE

Fluorescence spectra of ladderlike polyphenylsilsesquioxane (LPPS) and ladderlike 1,4-phenylene-bridgedpolyvinylsiloxane (LPPVS) have been measured as a function of temperature (4-55℃), in dilute tetrahydrofuran solution.The excimer (I_E) to monomer (I_M) intensity ratio (I_E/I_M) of LPPS dilute solution shows a double linear Arrhenius plot with abreak point ascribable to a transition temperature T_t This behavior has not been found for single chain polyorganosiloxanes.When InI_E of LPPS was plotted against I/T it also gave a double linear plot with one break point, which was found in singlechain polyorganosiloxanes. The different behaviors between LPPS and single chain polyorganosiloxanes may be mainlyattributed to the relatively rigid double-chain macromolecular backbone of LPPS. However, the In(I_E/I_M) of dilute LPPVSsolution versus I/T shows a simple linear variation with a positive slope which confirms our proposition. The differencebetween the fluorescence results of LPPS and those of LPPVS may possibly derive from their structure differences andcooperative motion in backbone chain bonds.     

合金钢中镍的快速测定——丁二肟直接比色法

钢铁中镍的测定,常用方法是丁二肟比色法。铁和其它干扰元素多采用柠檬酸盐及酒石酸盐络合掩蔽。但由于它们与铁生成的黄色络合物在镍与丁二肟所形成的络合物最大吸收470毫微米处有较大的光吸收,因此不分离铁及其他干扰元素测定镍时,一般都是选择灵敏度较低的530毫微米处进行比色测定。根据兄弟单位的经验,我们采用焦磷酸钠掩蔽铁。通过实验表明,50毫克铁存在时,焦磷酸钠的合适     

SYNTHESIS AND MESOGENIC PROPERTY OF Pd-COORDINATING AZO-TYPE SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANE

A novel palladium-coordinating Azo-type liquid crystalline polysiloxane (Pd-AZLCP) has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane(AZLCP), with palladium dichloride and potassium chloride in the presence of tetrahydrofuran (THF) as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T_i is increased and the mesophase range ΔT has been widened, too.     

SYNTHESIS AND CHARACTERIZATION OF β-DIKETONE BASED SIDE CHAIN LIQUID CRYSTALLINE POLYSILOXANES

A new type of β-diketone based side chain liquid crystalline polysiloxanes (DKLCP) with different length of flexible spacers and end groups have been synthesized by hydrosilation reaction. This is liquid crystal polymers (LCP) using coordinating β-diketone ligand as mesogens. The phase behaviour of DKLCP polymers was studied by differential scanning calorimetry and polarizing microscopy. X-ray diffraction investigations demonstrated that the polysiloxanes with sufficiently long flexible spacers were smectic liquid crystal polymers, while those with much shorter spacers were nematic ones.     

一类非光滑凸优化问题的邻近梯度算法

考虑求解目标函数为光滑损失函数与非光滑正则函数之和的凸优化问题的一种基于线搜索的邻近梯度算法及其收敛性分析,证明了在梯度局部Lipschitz连续条件下该算法是$R$-线性收敛的,并在非光滑部分为稀疏块LASSO正则函数情况下给出了误差界条件成立的证明,得到了线性收敛率。最后,数值实验结果验证了方法的有效性。     

SYNTHESIS OF HIGH THERMOSTABLE SILICONE GELS CONSTRUCTED WITH LADDERLIKE POLYSILSESQUIOXANES*

Heat-resistant silicone gels were synthesized by replacing the single main chain polymethylhydrosiloxane withreactive ladderlike polyhydrosilsesquioxane copolymers. Because of the interaction between polydimethylsiloxane chainsand the ladderlike polysilsesquioxanes chains, the cyclization of the polydimethylsiloxane chains is hindered. The highthermal stability of the ladderlike polymers can improve the thermal stability of the silicone gels without sacrificing their good comprehensive properties.     

非晶CoFeNiNbSiB合金的巨磁阻抗效应

研究了非晶Co₇₀Fe_4.5Ni₄Nb₁Si_12.5B₈合金薄带的巨磁阻抗效应.实验表明,在一定频率范围内提高测试频率,磁阻抗效应有明显提高;适当温度的退火也有助于磁阻抗效应的提高.制备态非晶合金样品在频率为5MHz下达120%左右,经过退火处理的非晶样品5MHz下的效应可达400%左右. 关键词：     

Polyorganosiloxane-europium (Ⅲ) host-guest inclusion system and its energy transfer luminescence

The Eu(Ⅲ) ion, as a luminescent probe, is incorporated into a novel nanotube-contained polyorganosiloxane (POS), which is obtained by coupling of ladderlike polyvinylsilsesquioxane (Vi-T) with tetramethyldisiloxane (H-MM) via hydrosilylation, to form POS-Eu(Ⅲ) composite. The results from fluorescent study demonstrate that the composite is actually a host-guest clathrate which includes the Eu(Ⅲ) ions in the tubelike cavity of POS and moreover, the supramolecular clathrate exhibits an obvious energy transfer process which converts the UV light absorbed by POS into the visible light generated from the Eu(Ⅲ) luminescence. Molecular simulation also gives support to the formation of such a clathrate and thus results in energy transfer process.     

MDI—1型微机测碘仪的研制

本文确定在硫酸铈催化比色法中,光电流对时间的一阶导数i′与碘离子浓度C呈线性关系。研制了MDI-1型微机测碘仪。线性范围0.5～80μg/L。相对偏差4.2％。分析速度30s/次(5～80μg/L碘)。应用于生物和环境样品中微量碘测定。仪器有自动显示结果和打印浓度值以及计算功能。中央处理器采用单片机8039。8位A/D转换器为ADC0809。