Synthesis and magnetic properties of polydiphenylamine derivative bearing stable radical groups

Poly[4,4′-diphenylamine (3,5-di-tert-butyl-4-hydroxy)benzylidene] was synthesized with a dehydrative polycondensation by using H₂SO₄ as a catalyst. After treatment with DDQ, the polymer was oxidized with PbO₂ to generate a stable radical group in the polymer. The colour of the polymer changed from green to dark red upon the oxidation. ESR spectra showed not only a signal with a g value of 2.004, but also a so-called ‘half-field’ signal with a g value of 4.288.     

Highly sensitive elemental analysis for Cd and Pb by liquid electrode plasma atomic emission spectrometry with quartz glass chip and sample flow

This paper describes the development of a highly sensitive liquid-electrode plasma atomic emission spectrometry (LEP-AES) by combination of quartz glass chip and sample flow system. LEP-AES is an ultracompact elemental analysis method, in which the electroconductive sample solution is put into a microfluidic channel whose center is made narrower (～100 μm in width). When high voltage pulses (1500 V) are applied at both ends of the channel, the sample evaporates locally at the narrow part and generates plasma. By the emission from the plasma, elemental concentration is analyzed. In this paper, the limits of detection (LODs) were investigated in various conditions of accumulation time, material of the chip, and the sample flow. It was found that the long accumulation using the quartz chip with sample flow was effective to improve LOD. Authors suggested that this was because bubbles remaining after each plasma pulse were removed from the narrow channel by sample flow, resulting in highly reproducible plasma generation, to enable a high accumulation effect. Finally, LODs were calculated from a calibration curve, to be 0.52 μg/L for Cd and 19.0 μg/L for Pb at optimized condition. Sub-ppb level LOD was achieved for Cd.     

混凝超滤工艺处理天津渤海湾海水

试验考核在线混凝超滤工艺预处理天津渤海湾海水的可行性,采用外压式中空纤维超滤膜,研究膜的最大膜通量,以及通过数据和理论公式分析得到该工艺的最佳化学强化清洗方式.试验分3阶段进行,每阶段采用不同膜通量和化学强化清洗方式.3个月试验结果表明:在跨膜压差≤75 kPa时能保证系统稳定运行的最大膜通量为54.2 L/(m2·h);最佳化学强化清洗方式为:气水擦洗,pH=2的H2SO4和质量分数120×10-6的NaClO相继连续清洗,气水擦洗,质量分数0.15×10-6亚硫酸氢纳浸泡,气水擦洗,清洗频率为1次/d;同时清洗效果表明,H2SO4和NaClO清洗对膜污染控制有不同的作用,H2SO4清洗有利于去除该工艺的不可逆污染物,NaClO清洗有利于减缓膜污染;试验产水满足反渗透进水要求,产水中未监测到藻类,产水浊度在0.06～0.1 NTU之间,SDI15<3,CODMn去除率为26%～45%.     

Effect of substrate orientation on Zn-doping of AIGalnP grown by atmospheric pressure orgamometallic vapor phase epitaxy

Dependence of hole concentration ofp(Zn) — (Al_0.6Ga_0.4In_0.5P on substrate orientation was examined. It increases with tilting the substrate from (100) towards (511)A. Addition of ann-GaAs cap layer on top of the quaternary increases hole concentration while ap-GaAs cap shows little effect.     

In situ tests for measuring cracks using a crack-detector

Bulletin of Engineering Geology and the Environment - A crack-detector using the ultrasonic pulse method has been developed for borehole measurements. The results obtained fromin situ tests are as...     

1,8-Cineole Inhibits Both Proliferation and Elongation of BY-2 Cultured Tobacco Cells

Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC₅₀) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC₅₀ lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed.     

Heat transfer enhancement and drag reduction of a flat plate normal to the airstream (flow control using a rod)

To control the flow around a flat plate, a small rod was set upstream of the plate. The chord length of the plate, D, was 50 mm. The diameter of the rod, d, and the distance between the axes of the rod and plate, L, were varied. The Reynolds number ranged from 1.3 × 10⁴ to 7.7 × 10⁴. For the cases without vortex shedding from the rod, the shear layer from the rod reattaches to the front face of the plate. Consequently, quasi-stationary vortices are formed between the rod and the plate. In this case, at d/D = 0.4 and L/D = 1.4 to 2.0, the maximum reduction of total drag coefficient is 20 to 30%. The average heat transfer on each face increases and the overall heat transfer increases by about 40 to 50% compared with values obtained without the rod in place. © 1998 Scripta Technica, Heat Trans Jpn Res, 27(2): 99–113, 1998