MIDP2.0中AMS对MIDlet生命周期控制的设计与实现

本文首先对MIDP2．0和AMS进行了简要介绍。然后对MIDlet的生命周期展开了详细的讨论。最后通过对几个协同完成控制功能的类的分析,描述了AMS对MIDlet生命周期控制的设计和实现。     

粉末PET固相缩聚的研究

系统地研究了粉末聚酯(PET)固相缩聚,得到了有效的干燥结晶条件:140℃干燥120 min,180℃再结晶45 min,切片含水率低于30μg／g;研究了反应温度,粉末粒径和N2流量对PET固相缩聚的影响,分析粉末固相缩聚存在N2流量阈值的机理。结果表明:反应温度越高,颗粒越小,固相缩聚反应速度越快;粉末 PET预聚体在一定温度下固相缩聚,存在N2流量阈值。在此流量下,达到该温度下的该粒径粉末的最大界面扩散速率和固相缩聚的最大反应速度。相同反应温度下,粉末粒径越小,阈值N2流量越大。     

嵌入式移动代理的设计与实现

随着移动通信的快速发展,以及手持移动设备的增多,人们已经进入到一个移动计算的时代。移动管理是移动通信中的核心问题。针对IETF的移动IP协议的不足,论文提出了基于嵌入式WindowsCE.net操作系统实现通信设备的移动管理方案。首先简述移动IP协议,并指出其不足之处;然后介绍了嵌入式移动代理的整体框架;最后详细说明了移动代理的实现。该方案主要特点如下:可以最大限度地减小移动管理对移动管理基础设施的依赖;嵌入式移动代理可以为操作系统提供透明的移动服务。     

Corrosion behaviour of Al1.3CrFeNi chemically complex alloy

In this study, corrosion behaviour of double-phase Al_1.3CrFeNi chemically complex alloy was investigated, including hot corrosion and electrochemical corrosion. Hot corrosion behaviour of Al_1.3CrFeNi alloy was explored in molten 75 wt-% Na₂SO₄?+?25 wt-% NaCl salt. The result revealed that the corrosion kinetic curve of Al_1.3CrFeNi alloy followed the exponential rate rule through mass loss measurement. In addition, it prevented that the formed corrosion layer had obvious stratification including external granular Al₂O₃ and inner porous Cr₂O₃ when corrosion time was up to 100?h. Besides, it should be noted that the Al_1.3CrFeNi alloy was sensitive to the molten salt containing chlorine, which makes the alloy surface leave voids and bring about acceleration of corrosion. Meanwhile, electrochemical corrosion resistance of Al_1.3CrFeNi alloy in NaCl solution with different concentrations (0.6, 1.0 and 2.0?mol?L^?1) was investigated at room temperature. The results revealed that Al_1.3CrFeNi alloy showed superior corrosion resistance in NaCl solution due to the existence of Al and Cr which aid the formation of protective oxide layer.     

Molecular Identification of the G-Protein Genes and Their Expression Profiles in Response to Nitrogen Deprivation in Brassica napus

Heterotrimeric guanine nucleotide binding protein (G-protein) consisting of Gα, Gβ, and Gγ subunits is one of the key signal transducers in plants. Recent studies indicated that G-protein has been proposed as an important mediator of nitrogen responses in rice, wheat, and Arabidopsis. However, little is known about these G-proteins in Brassica napus (B. napus), except for three identified G-proteins, BnGA1, BnGB1, and BnGG2. Therefore, the aim of the present study is to characterize the members of the G-protein gene family in allotetraploid B. napus and to analyze their expression profiles in response to nitrogen deprivation. In total, 21 G-protein family members were identified in B. napus, encoding two Gα, six Gβ, and 13 Gγ. Sequence and phylogenetic analyses showed that although genome-wide triploid events increased the number of genes encoding Gα, Gβ, and Gγ subunits, the gene structure and protein properties of the genes encoding each G-protein subunit were extremely conserved. Collinearity analysis showed that most G-protein genes in B. napus had syntenic relationships with G-protein members of Arabidopsis, Brassica rape (B. rapa), and Brassica oleracea (B. oleracea). Expression profile analysis indicated that Gα and C-type Gγ genes (except BnGG10 and BnGG12 were highly expressed in flower and ovule) were barely expressed in most organs, whereas most Gβ and A-type Gγ genes tended to be highly expressed in most organs. G-protein genes also showed various expression patterns in response to nitrogen-deficient conditions. Under nitrogen deficiency, Gα and five C-type Gγ genes were upregulated initially in roots, while in leaves, Gα was downregulated initially and five C-type Gγ genes were highly expressed in different times. These results provide a complex genetic dissection of G-protein genes in B. napus, and insight into the biological functions of G-protein genes in response to nitrogen deficiency.     

紫外分光光度法测定水溶液中的磺酸盐

文章研究了紫外分光光度法测量水相中磺酸盐浓度的方法。实验结果表明,磺酸盐的最大吸收波长均为225nm,单一体系和复配体系的工作曲线方程相同。研究了磺酸盐浓度、相态对测定结果的影响.实验表明,该方法重现性好,可操作性强,准确快速,可直接应用于10^7-10^-4M的磺酸盐浓度测定。     

某待建滨海核电厂厂址年均大气扩散因子计算模式与参数的实验研究

本文在某待建滨海核电厂厂趣现场野外实验基础上提出了计算该核电厂年均大气扩散因子的计算模型。此模型既考虑了向岸流与离岸流的差别,又考虑了混合层与热内边界层,混合释放与扩散参数随陆距变化等因素的综合影响。模型中所需要的各类参数,包括在１９９５,１９９６年间在该厂趣野外大气试验中获取的百米气象铁塔４个不同高度上的风,温逐时三维联合频率;湍流测量结合风洞实验获取的离岸流与向岸流的扩散参数。     

LD31合金高压瓶衬旋压成形组织与性能

ＬＤ３１合金瓶衬经冷热加工成形,其显微组织和力学性能不断改善,有助于获取优质高压气瓶。ＬＤ３１合金毛坯不及热开坯旋压厚壁管,为大有率的冷旋薄壁管创造了条件。ＬＤ３１冷旋性能良好,累计变薄率达７０％,其形变强化明显。加热缩旋的瓶衬经淬火时效后,Ｍｇ２Ｓｉ强化相弥散析出,相变强化显著,综合性能尚好,有利于提高玻璃纤维复合缠绕高压气瓶的使用性能。