Photocatalytic oxidation of low concentration 2,4-D solution with new TiO2 fiber catalyst in a continuous flow reactor.

Environmental pollution by low concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) is a concern these days due to ever increasingly stringent regulations. Photocatalysis with immobilized TiO2 fiber is a promising oxidation method. Laboratory experiments on photocatalytic degradation of 0.045 mmol l(-1) 2,4-D with the world's first high-strength TiO2 fiber catalyst were carried out in a continuous flow reactor in which the degradations were, in general, similar to those with high 2,4-D concentrations investigated elsewhere. Degradation and mineralization of 2,4-D were significantly enhanced with no initial pH adjustments. The rate constants for total organic carbon (TOC) without pH adjustment were about two-fold bigger than the pH adjustment cases. CO2 gas measurement and carbon mass-balance were carried out for the first time, where about 34% organic carbon converted into CO2 gas during four-hour oxidation. 2,4-Dichlorophenol (2,4-DCP), phenol, benzyl alcohol and two unknowns (RT = 2.65 and 3.78 min.) were detected as aromatic intermediates while Phenol was the new aromatic in HPLC analysis. Dechlorination efficiencies were high (> 70%) in all the cases, and more than 90% efficiencies were observed in chloride mass balance. Bigger flow rates and solution temperature fixed at 20 degrees C without pH adjustment greatly enhanced 2,4-D mineralization. These results can be an important basis in applying the treatment method for dioxin-contaminated water and wastewater.     

基于小波神经网络的信号识别

信号的分选和识别技术在当今信号处理的系统中占有相当重要的地位.小波分析和神经网络是近年来兴起的一种分析信号方法.文中对二者的结合问题进行了研究.小波空间可以作为信号分类的特征空间,进而可以通过神经网络对信号进行特征识别.小波神经网络是基于小波分析而构造的神经网络模型.在信号调制类型识别中,利用小波伸缩平移把信号分解到不同频道上进行特征提取;把提取的特征信息输入神经网络进行分类.仿真结果表明,利用此方法可以较好的对信号进行分选和识别.     

Transmittance and cathodoluminescence of AlN ceramics sintered with Ca3Al2O6 as sintering additive

Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca₃Al₂O₆ (C₃A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C₃A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C₃A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density.     

Phase behavior in liquid crystallization for diblock copolymers consisting of rubbery amorphous and side-chain liquid crystalline components

Phase behavior in liquid crystallization was studied for a series of liquid crystalline (LC) diblock copolymers consisting of rubbery amorphous and side-chain liquid crystalline components, poly(n-butyl acrylate) (PBA) and poly[11-(4′-cyanophenyl-4″-phenoxy)undecyl acrylate] (PLC), respectively, using a time-resolved small-angle X-ray scattering (SAXS) techniques, DSC and polarized optical microscopy (POM). The block copolymers used had three kinds of copolymer compositions, 44, 20 and 15 wt% of PLC compositions (BLC44, BLC20 and BLC15, respectively). BLC44 showed a smectic liquid crystalline structure. In the process of liquid crystallization for BLC44, the SAXS peak due to the microphase separation structure existing before liquid crystallization was changed continuously to be at a smaller angular side, and at almost the same time, a new peak appeared at a further smaller angular side and developed. The former peak disappeared with the development of liquid crystallization. The behavior of these SAXS peaks suggests that the microphase separation structure was changed discretely at the transition from isotropic to smectic and that two phases coexist in the early stage of the liquid crystallization. The coexistence of two peaks in the early stage of the liquid crystallization corresponded to the POM observation. In the isotropization process, coexistence of two phases was not observed. For BLC20 exhibiting a cylindrical structure in both isotropic and liquid crystalline states, the liquid crystalline structure was not smectic but probably nematic, and the spacing was changed continuously in liquid crystallization. No liquid crystallization was observed in SAXS, POM and DSC for BLC15. The orientation of smectic layers within lamellar domains was investigated using 2D-SAXS images. The smectic layer was aligned perpendicularly to the lamellar interface.     

A novel brain-derived member of the epidermal growth factor family that interacts with ErbB3 and ErbB4

The availability of an analgesic compound devoid of the side effects associated with the commonly used opioid and nonsteroidal antiinflammatory drugs would be useful during the perioperative period. Although adenosine has analgesic and anesthetic-sparing properties, it also produces dose-dependent cardiovascular depression. Inhibitors of adenosine kinase may be able to provide analgesia without producing acute cardiovascular or respiratory depression. This preliminary study investigated the effects of a novel adenosine kinase-inhibiting drug, GP683, on the minimum alveolar anesthetic concentration (MAC) of desflurane in dogs. Seven mongrel dogs were administered one of three different GP683 dose regimens (or the solvent) by intravenous infusion on separate occasions according to a cross-over study design. After determining the baseline desflurane MAC value, GP683 was infused at 75, 150, or 300 microg x kg(-1) x min(-1) for 5 min as a loading dose, followed by 15, 30, or 60 microg x kg(-1) x min(-1) for an additional 85 min to maintain a stable plasma drug level. The desflurane MAC was redetermined 30-90 min after starting the study drug or vehicle infusion, and 30-90 min and 120-180 min after termination of the infusion. Cardiovascular variables and plasma concentrations of GP683 were determined at specific intervals before, during, and after the MAC determinations. The three GP683 dose regimens produced 22%, 31%, and 50% decreases in the desflurane MAC, respectively. In addition, there was good correlation between the decrease in desflurane MAC and the plasma GP683 concentration (r = -0.78). Although the mean arterial pressure (MAP) was decreased up to 25% by the highest infusion rate of GP683, adjustments in the desflurane concentration to an equi-MAC value resulted in normalization of the MAP values. Furthermore, GP683 produced no changes in heart rate. In conclusion, the adenosine kinase-inhibiting drug, GP683, produced dose-dependent decreases in the desflurane MAC of dogs without producing untoward hemodynamic changes. IMPLICATIONS: An investigational drug (GP683) that can increase the levels of an important endogenous substance in the body (adenosine) has been found to decrease the anesthetic requirement in dogs without producing adverse effects on the cardiovascular system.     

Modulation characteristic of waveguide-type optical frequency combgenerator

We report the modulation characteristics of a waveguide-type optical frequency comb generator (WG-OFCG) with the advantages of compactness, high modulation index and low driving power. The characteristics of the optical frequency comb (OFC) generated when the modulation index exceeds 2π are discussed. The power of the modulation sidebands was measured by the optical heterodyne method with an external-cavity laser as a local oscillator. The dependence of the modulation index of the WG-OFCG on the modulation frequency up to 40 GHz was measured. The generation span of the OFC at the modulation frequency detuned from an integer multiple of the free spectral range (FSR) is discussed     

Cloning, tissue expression, and chromosomal localization of the mouse IRS-3 gene

Insulin receptor substrate (IRS) proteins are key regulators of basic functions such as cellular growth and metabolism. They provide an interface between multiple receptors and a complex network of intracellular signaling molecules. Two members of this family (IRS-1 and IRS-2) have been identified previously. In this investigation, we analyzed a mouse expressed sequence tag clone that proved to be a new member of the IRS family. Sequence analysis of this clone and comparison with the sequences deposited in GenBank demonstrates this protein may be the murine homolog of rat IRS-3, recently purified and cloned from rat adipocytes. Accordingly, we have named our protein mouse IRS-3. The expressed sequence tag clone contains the complete coding sequence of 1485 bp, encoding a protein of 495 amino acids. Sequence alignment with the other members of the IRS family shows that this protein contains pleckstrin homology and phosphotyrosine-binding domains that are highly conserved. In addition, there is conservation of many tyrosine phosphorylation motifs responsible for interactions with downstream signaling molecules containing SH2 domains. The murine IRS-3 messenger RNA (2.4 kilobases in length) is expressed in many tissues, with highest levels in liver and lung. Mouse IRS-3 is highly expressed in the first part of the embryonic life, when IRS-1 messenger RNA is barely detectable. Unlike the genes encoding IRS-1 and IRS-2, the IRS-3 gene contains an intron (344 bp in length) in the region between the pleckstrin homology and the phosphotyrosine-binding domains. Fluorescent in situ hybridization localized the mouse IRS-3 gene on the telomeric region of chromosome 5G2. Cloning of the murine IRS-3 gene will make it possible to apply genetic approaches to elucidate the physiological role of this new member of the IRS family of proteins.     

双乙醛草酰二肼直接快速光度法测定食品中痕量铜

研究了双乙醛草酸二肼与铜的显色反应，建立了分光光度法直接测定铜的新方法。试验结果表明，在pH8．0－10．0范围内，Cu2 与双乙醛草酸二肼形成稳定的紫红色配合物。该配合物在540nm处有一最大吸收峰，其表明摩尔吸光系数为2．4×104，铜量在0－12mg／50ml范围内符合比尔定律。共存离子干扰，误差仅 2.00％。用于食品中痕量钢测定．结果准确、可靠。     

C51嵌套汇编子程序在阻抗测试仪研制中的应用

C51嵌套汇编子程序，充分发挥了两种语言自的优势，介绍了C51调用汇编子程序的接品规则，并通过阻抗测试仪程序开发的例子予以详细说明。