Call control and traffic transport for connection-oriented highspeed wireless personal communications over metropolitan area networks

A distributed circuit-switched approach for supporting the deployment of high speed wireless personal communication services in urban areas through the interconnection of base stations via metropolitan area networks (MANs) is proposed. Broadband MANs minimize traffic congestion by dynamic sharing of link capacity and by serving as distributed switches for partitioning call control functions. While the DQDB protocol readily supports distributed packet-switching over the IEEE 802.6 MAN, isochronous traffic such as voice and video is best supported by circuit-switched connections. The authors present an enhanced bi-state pre-arbitrated (PA) transport mechanism, and associated call control and handoff management techniques, which enable distributed circuit-switching over the MAN. These capabilities are not currently addressed in the 802.6 standards. The bi-state PA transport mechanism facilitates statistical multiplexing of variable rate isochronous traffic sources. The network capacity is constrained by the call setup delay performance, and is analyzed by simulations. Alternative signaling architectures, involving different placements of call control network elements, are evaluated. The effects of erasure nodes, and close bus versus open bus architectures, are considered. The overlap inter-MAN call setup procedure is proposed to reduce delays. Different call handoff procedures are formulated according to the type of handoff and the resulting change in call connectivity. Most handoffs are intra-MAN, requiring simple procedures with short delays     

厌氧胶快速渗补技术在汽车发动机上的应用

将金属铜易与过氧化物发生氧化还原反应生成游离基的原理应用于厌氧胶，开发了针时金属零件表面微孔进行局部渗补的实用技术。在相关技术可靠性和工艺可行性得以论证的前提下。将局部渗补技术成功地应用于渗补发动机泄漏缸盖，减少了废品损失，取得了良好的经济效益。     

A hexane solution deposition of SnS2 films from tetrabutyltin via a solvothermal route at moderate temperature

SnS₂ films have been deposited on glass and alumina plate substrates by the reactions between an organotin precursor [tetrabuyltin, (CH₂CH₂CH₂CH₃)₄Sn] and carbon disulfide in n-hexane at the temperature range 180-200 °C for 10-40 h. The reaction system was oxygen free and applied at a moderate temperature. The films so prepared were characterized by techniques of X-ray diffraction, Scanning electron microscopy, Raman and Mössbauer spectroscopies. The films deposited on glass as well as on alumina plate have an average thickness of 30 μm, but have different rose-like morphologies, which are influenced by both the anisotropic growths of crystals and the different substrate structures. Photoluminescence measurements show that the films have an emission peak at approximately 590 nm.     

精馏塔静态仿真：Ⅰ.静动态混合数学模型的应用

本文为了克服精馏塔静态仿真不易收敛和初值难以给定等难题，巧妙地利用隐含数值积分方法的特点，将稳态与动态数学模型耦合起来，用以求解高难度的非理想精馏塔静态仿真问题。所得静动态混俣模型大大提高了精馏塔静态仿真的鲁棒性，对于高度非理想精馏塔的仿真尤为有效。通过对某丙烯腈萃取精馏塔的静态仿真，充分证明了这种混合模型化方法的可行性。     

^125I,^131I诱发小鼠精子畸形发生率比较

本文选用 ICR 雄性小鼠,经腹腔分别注射不同剂量的~(125)I 及~(131)I,观察并比较它们对小鼠精子畸形发生率的影响及染毒后睾丸中放射性活度的变化。实验结果表明:(1)~(125)I 染毒后4—5周,0、185、370和555 kBq 各组精子畸形发生率分别为9.00‰、9.57‰、11.6‰及13.9‰;~(131)I 染毒后4—5周,上述各组精子畸形发生率分别为8.50‰、12.5‰、14.7‰和15.5‰;在相同注入量下,~(125)I 与~(131)I 诱发小鼠精子畸形发生率的差异各组均不显著(X~2检验,p>0.05)。(2)~(125)I、~(131)I 染毒后2h 至7天内,两者在睾丸中的放射性活度及变化规律相似,即在染毒后2h 达最高值,每克睾丸中~(125)I 和~(131)I 的放射性活度分别占初始注入量(370 kBq)的0.72％和0.50％,然后迅速下降,至一周时,仅分别占初始注入量的0.035％和0.011％。     

An algebraic method for processing colored images

An 8-valued commutative ring is developed to process colored images. Algebraic operators are defined to perform a number of operations such as the extraction of the primary colors and contours of different colors.     

Variational principle of combined energy—Mechanics of laminated structures

The conventional approaches for stress analysis of composite laminates have encountered discontinuity problems. In this paper, the C¹ continuity of displacements in the in-plane directions and C⁰ continuity of displacement along the thickness direction are discussed. Also, the global continuity of transverse stresses and local continuity of in-plane stresses are examined. Then, the formulations of stress analysis in both differential equation form and variational functional form are presented.     

为网络发展注入文化的灵魂

“为网络注人文化的灵魂，为文化插上网络的翅膀”这句在2003中国首届国际网络文化博览会上四处飘扬的标语清楚地表明，当代信息革命在经历了从硬件为王到软件为王的转型过程后。正从网络为王时代走向内容为王时代；文化的本体形态、经济形态、技术形态伴随着信息技术的飞速发展正在     

MX345芯片及单片机控制

MX345芯片用于产生模拟信令—CTCSS单音.本文在介绍MX345编码/解码器工作原理的基础上,设计出MX345芯片与单片机的接口电路.最后给出控制软件.     

LF精炼造渣工艺研究

根据炼钢厂第一连铸车间钢包炉造渣的特点,利用炉渣组元CaO、SiO2、Al2O3、CaF2进行分析研究,制定出合理的渣系配比和造渣制度,通过实践取得了稳定的脱硫、脱氧效果.