1,3-二氨基硫脲的制备

以水合肼和二硫化碳为原料合成了1,3-二氨基硫脲(简称TCH)。确定了合成中间体HDTC的最适宜工艺条件为水合肼:C_2=2.2:1(物质的量比)、温度 20℃、反应时间45min。重点对HDTC分解生成最终产物TCH的工艺进行了改进,结果表明:当HDTC分解反应在水合肼溶液中进行,并加入适量的仰制剂,不仅可使反应时间从20h缩短至8h,而且第一步反应结束后不必除去过量的水合肼即可进行第二步反应,TCH的产率接近90％。     

The Xyloglucan Endotransglucosylase/Hydrolase Gene XTH22/TCH4 Regulates Plant Growth by Disrupting the Cell Wall Homeostasis in Arabidopsis under Boron Deficiency

TCH4 is a xyloglucan endotransglucosylase/hydrolase (XTH) family member. Extensive studies have shown that XTHs are very important in cell wall homeostasis for plant growth and development. Boron (B), as an essential micronutrient for plants, plays an essential role in the cross-linking of cell wall pectin. However, the effect of B on cell wall organization is unclear. This study aimed to explore the mechanism of plant adaption to B stress by investigating the role of TCH4 in cell wall homeostasis. We conducted both plate and hydroponic cultures of wild-type Col-0 and overexpression and gene knockout lines of XTH22/TCH4 to analyze the phenotype, components, and characteristics of the cell wall using immunofluorescence, atomic force microscopy (AFM), and transmission electron microscopy (TEM). B deficiency induces the expression of TCH4. The overexpression lines of TCH4 presented more sensitivity to B deficiency than the wild-type Col-0, while the knockout lines of TCH4 were more resistant to low B stress. Up-regulation of TCH4 influenced the ratio of chelator-soluble pectin to alkali-soluble pectin and decreased the degree of methylesterification of pectin under B-deficient conditions. Moreover, we found that B deficiency disturbed the arrangement of cellulose, enlarged the gap between cellulose microfibrils, and decreased the mechanical strength of the cell wall, leading to the formation of a thickened and deformed triangular region of the cell wall. These symptoms were more profound in the TCH4 overexpression lines. Consistently, compared with Col-0, the O₂⁻ and MDA contents in the TCH4 overexpression lines increased under B-deficient conditions. This study identified the B-deficiency-induced TCH4 gene, which regulates cell wall homeostasis to influence plant growth under B-deficient conditions.     

GSM系统中TCH自适应均衡解调算法的研究

针对移动信道多径效应造成的严重的符号间干扰（ISI）问题，研究了基于最大似然序列估计（MLSE）的GSM系统中TCH自适应均衡解调算法，并对这种自适应均衡解调算法在Jake移动信道模型环境下的性能进行了分析和计算机仿真，仿真结果表明，该自适应均衡解调算法能够很好地克服符号间干扰（ISI）问题，性能良好。     

GSM系统的业务量控制

通信网中的业务量控制是维持正常操作所必不可少的技术 ,本文介绍了当今使用较多的GSM数字移动通信系统在业务量控制上所采取的一些基本方法。     

Microwave-accelerated cytochemical stains for the image analysis and the electron microscopic examination of light microscopy diagnostic slides

Recent studies in our laboratories have shown how microwave (MW) irradiation can accelerate a number of tissue-processing techniques, especially staining, to aid in the preparation of single specimens on glass microscope slides or coverslips for examination by light microscopy (and electron microscopy, if required) for diagnostic purposes. Techniques have been developed, which give permanently stained preparations, that can be studied initially by light microscopy, their areas of interest mapped, and computer-automated image analysis performed to obtain quantitative information. This is readily performed after MW-accelerated staining with silver methenamine by the Giammara-Hanker PATS or PATS-TS reaction. This variation of the PAS reaction gives excellent markers for specific infectious agents such as lipopolysaccharides for gram-negative bacteria or mannans for fungi. It is also an excellent stain for glycogen and basement membranes and an excellent marker for type III collagen or reticulin in the endoneurium or perineurium of peripheral nerve or in the capillary walls. Our improved MW-accelerated Feulgen reaction with silver methenamine for nuclear DNA is useful to show the nuclei of bacteria and fungi as well as of cells they are infecting. Improved coating and penetration of tissue surfaces by thiocarbohydrazide bridging of ruthenium red, applied under MW-acceleration, render biologic specimens sufficiently conductive for SEM so that sputter coating with gold is unnecessary. The specimens treated with these highly visible electron-opaque stains can be screened with the light microscope after mounting in polyethylene glycol(PEG) and the structures or areas selected for EM study are mapped with a Micro-Locator? slide. After removal of the water soluble PEG the specimens are remounted in the usual EM media for scanning electron microscopy (SEM) or transmission electron microscopy (TEM) study of the mapped areas. By comparing duplicate smears from areas of infection, such as two coverslips of buffy coat smears of blood from a patient with septicemia, the microorganisms responsible can occasionally be classified for antimicrobial therapy long before culture results are available; gram-negative bacteria are positive with the Giammara-Hanker PATS-TS stain, and gram-positive bacteria are positive with the SIGMA HT40 Gram stain. The gram-positive as well as gram-negative bacteria are both initially stained by the crystal violet component of the Gram stain. The crystal violet stain is readily removed from the gram-negative (but not the gram-positive) bacteria when the specimens are rinsed with alcohol/acetone. If this rinse step is omitted, the crystal violet remains attached to both gram-negative and gram-positive bacteria. It can then be rendered insoluble, electron-opaque, and conductive by treatment with silver methenamine solution under MW-irradiation. This metallized crystal violet is a more effective silver stain than the PATS-TS stain for a number of gram-negative spirochetes such as Treponema pallidurn, the microbe that causes syphilis     

小灵通通信网络中基站数量的限制因素

为更好地规划和优化小灵通移动通信网,本文根据PHS网络无线规划的特点,从工程上和理论上探讨了小灵通移动通信网在无线网络中规划基站数量时的三个限制因素,即最大距离限制、控制信道同时隙干扰限制和业务信道同频干扰限制,解决了目前小灵通网络在无线资源受限情况下做无线规划和优化时,对基站进行调整缺少理论指导和依据的问题。     

中兴领先技术，时刻节能降耗——GSM智能节电技术分析

在GSM网络建设的总拥有成本(TCO)中,设备的电力消耗是运营成本(OPEX)中重要的组成部分,如何降低设备功耗,节约用电,已经成为运营商关注的焦点之一。文章介绍了目前基站的使用现状,以及中兴通讯的节电建设思路——通过一系列业界领先的智能节电技术实现基站设备功耗大幅降低,有效保护生态环境,降低运营成本。     

华为GSM掉话统计机制及参数优化研究

文章主要结合华为BSC的A接口、Abis接口信令跟踪功能,通过详细的优化试验,总结出华为GSM设备在掉话统计机制方面的原理,并分析其对通话流程以及用户感知的影响,总结出掉话相关参数的设置建议值。     

无线通信系统中信道拥塞动态调整的研究

无线通信系统的信道拥塞率能准确地反映信道的使用情况。分析了无线通信网覆盖中产生的信道拥塞，提出一种基于信道拥塞率的动态调整算法。该算法通过对无线通信系统网络侧统计数据的分析，动态调整系统中的信令信道和业务信道的比例，以解决无线通信系统中信道拥塞的问题。在相同的话务模型下，对算法应用前后进行仿真比较。仿真结果表明，采用所提算法可以提高网络的质量，特别是当短时间多用户同时申请信道时，可以明显提高系统的接通率。     

小灵通呼叫成功率优化方法

呼叫成功率反映了PHS网络无线侧的总体接入性能,与掉话率共同成为无线侧两大关键指标。随着PHS网络优化的不断深入以及考核的要求,呼叫成功率的优化已经成为广大网优技术人员积极探索的重点项目,但由于思路不正确,许多网优人员在优化过程并没有找到问题的主要因素,因此不能取得理想的网优效果甚至导致网络性能的恶化。这篇论文通过对呼叫成功率的指标分解、因素分析以及优化方法的介绍,以及对网优经验的总结,为技术人员对该指标的理解以及优化方法提供参考,以达到提高网优效率的目的。