机电产品材料PVC中二噁英的高分辨质谱法定量测定

二噁英是指包括75种多氯代二苯并-对-二噁英(polychlorodibenzo-p-dioxin,PCDD)和135种多氯代二苯并呋喃(polychlom-dibenzofuran,PCDF)的一组多氯代的平面芳烃化合物.二噁英是目前已知最毒的化合物,研究发现17种具有2,3,7,8位氯取代的二嗯英同族体毒性远高于其它同族体,其中,2,3,7,8.四氯二苯并-对-二噁英(2,3,7,8.TCDD)对于雄性小豚鼠的LD50仅为0.6μg/kg[1].二噁英还有极强的致癌和内分泌干扰作用,人体长期低剂量的接触二噁英会导致癌症、雌性化和胎儿畸形等.     

钢丝绳模型比较研究

将现有的各种钢丝绳计算模型进行比较研究，通过将数值结果与现有的实验数据进行比较可以看出，考虑绳芯变化并结合Love曲杆理论的JW和KC模型更适用于实际的钢丝绳结构。     

Comparative Characterization of InGaN/GaN Multiple Quantum Wells by Transmission Electron Microscopy, X-Ray Diffraction and Rutherford Backscattering

The composition, elastic strain and structural defects of InCaN/CaN multiple quantum wells （MQWs） are comparatively investigated by using x-ray diffraction （XRD）, transmission electron microscopy and Rutherford backscattering/channelling. The InGaN well layers are fully strained on CaN, i.e. the degree of relaxation is zero. The multilayered structure has a clear defined periodic thickness and abrupt interfaces. The In composition is deduced by XRD simulation. We show how the periodic structure, the In composition, the strain status and the crystalline quality of the InGaN/GaN MQ, Ws can be determined and cross-checked by various techniques.     

Lipogenesis stimulatory and inhibitory activities of the insulin mediators

Incubating plasma membranes prepared from pig liver with varying concentrations of insulin (50-1000 microU/ml) resulted in the release of at least two insulin chemical mediators. One of them was fraction 1 of insulin mediator (M. W. 3700-4000 daltons) which had a significant lipogenesis-stimulating activity. The other was fraction 2 of insulin mediator (M. W. about 1000 daltons) which exhibited a lipogenesis-inhibitory activity. The ratio of yield between the two mediators produced from the membranes was not only dependent on the concentration but also on the potency of insulin and its analogs added. The result showed that there was more production of fraction 2 than fraction 1 with the inducer at low concentration (100 microU/ml), while the production of fraction 1 from the plasma membranes incubated with high concentration of insulin (300 microU/ml) was higher than fraction 2. On the other hand, insulin and its analogs which have different biological activities and receptor binding activities have been used to induce the insulin mediators. The results obtained were similar to those mentioned above. This suggested that the generation of the mediators was dependent on the biological potences but not the binding activities.     

Synthesis of aminomethyl and amino analogs of 5-benzylacyclouridine and 5-benzyloxybenzylacyclouridine

Amino analogs of BAU (5-benzylacyclouridine) and BBAU (5-benzyloxybenzylacyclouridine) and their 2′-hydroxymethyl derivatives were synthesized for evaluation as inhibitors of uridine phosphorylase and hence potential cancer chemotherapeutic agents. Both aminomethyl analogs were found to be potent inhibitors of this enzyme and good potentiators of the anti-tumor action of FUdR.     

The key factors in fabrication of high-quality ordered macroporous copper film

The template-directed fabrication of highly-ordered porous film is of significant importance in implementation of the photonic band gap structure. The paper reports a simple and effective method to improve the electrodeposition of metal porous film by utilizing highly-ordered polystyrene spheres (PSs) template. By surface-modification method, the hydrophobic property of the PSs template surfaces was changed into hydrophilic one. It was demonstrated that the surface modification process enhanced the permeability of the electrolyte solution in the nanometer-sized voids of the colloidal template. The homogeneously deposited copper film with the highly-ordered voids in size of less than 500 nm was successfully obtained. In addition, it was found that large defects, such as microcracks in the template, strongly influenced the macroporous films quality. An obvious preferential growth in the cracked area was observed.