Cellular roles in relapse processes of experimentally-moved rat molars.

This histological study was designed to clarify the relapse processes of rat molars following orthodontic tooth movement by the Waldo method. An elastic band was inserted between the upper first and second molars, and removed either 7 or 21 days later. The relapse processes of first molars were examined at 1 or 4 days after completing the 7-day-insertion and at 5 or 10 days after the end of the 21-day-insertion. At the end of the 7-day-insertion period, the mean interdental space was 158 microns, but decreased rapidly, reaching 44 microns by 1 day after removal, and 16 microns by day 4. In the periodontal ligament (PDL) compressed by elastic band insertion, partial hyalinization and/or mineralization occurred. The stretched PDL consisted of irregularly-distributed, thin principal fibres, approximately 2.4 microns in diameter. On days 1 and 4 after removal, osteoclasts, macrophage-like cells and fibroblast-like cells were localized around hyalinized tissues, but thick principal fibres, approximately 3.8 microns in diameter, were regularly distributed throughout the PDL proper. The mean interdental space after the 21-day-insertion was 536 microns, but this had decreased to 108 microns by day 5, and 71 microns by day 10. On day 5 after removal, numerous osteoclasts were evenly distributed in the compressed PDL, while thick principal fibres, approximately 3.5 microns, were present in the stretched PDL. These results suggest that, during relapse of experimentally-moved rat molars, (i) rapid remodelling of the PDL and surrounding alveolar bones is the main cause of tooth relapse and (ii) hyalinized and/or mineralized tissues occurred by compression are rapidly resorbed by osteoclasts, macrophage-like cells and fibroblast-like cells.     

Cellular Kung-fu Grip

Researchers at Johns Hopkins University have developed 700?micrometer metallic grippers that can be remotely triggered to clench.     

蜂窝IP技术的探讨

蜂窝ＩＰ技术作为Ｉｎｔｅｒｎｅｔ移动接入技术的重要组成部分,是移动通信网下Ｉｎｔｅｒｎｅｔ网相结合的产物。它解决了无线接入Ｉｎｔｅｒｎｅｔ网主机频繁移动性问题,弥补了移动ＩＰ的５缺陷。介绍蜂窝ＩＰ的协议,对其网络实体和关键技术进行了探讨。     

Cellular packet communications

The future of third-generation wireless networking is discussed. The vision of the third generation is a single set of standards that can meet a wide range of wireless access applications. Third-generation systems, in harmony with broadband integrated services digital networks, will use shared resources to convey many information types. A single network architecture will serve its users efficiently in many environments, including moving vehicles, indoor and outdoor public areas, residences, offices, and factories. A study of a switching architecture, referred to as a cellular packet switch, and a packet transmission technique, referred to as a packet reservation multiple access is discussed. By means of a design example, it is shown how these techniques can work together to meet some of the demands of third-generation systems     

Multi-Tier Cellular Network Dimensioning

Wireless communications systems enable the end users to be mobile. The majority of the wireless communications networks are cellular networks. Several methods are developed to increase the performance of the cellular networks, which depends on the correct determination of the design parameters as well as the architecture of the system and the traffic requirements. In this study, we introduce a Simulated Annealing (SA) based method to determine the design parameters of a multi-tier cellular network, for which the implementation cost is minimized. The cellular system employs guard channels and allows calls to overflow to upper tiers. We conducted experiments with the SA-based technique on different example problems in two-tier cellular networks and obtained promising results.     

1999年中国蜂窝移动通信及手机市场走向分析

中国移动电话数已跃居世界第三位，增长速度在部分城市妆近或开始超过普通固定电话。而在设备市场上，中国开发的ＧＳＭ产品正在取得突破性进展，开始了国外产品的角逐，手机市场尤其如此。此外，中国移动通信标准的选择正处于关键时刻，可能影响到第三代移动通信技术的选用。     

蜂窝手机市场和技术发展趋势

从2004年末到2005年初,多数业界观察家预测今后手机业务增长率将减慢,增长速度预测不超过10%,而目前手机业务的最大潜能是为新兴市场开发极低成本手机.这种发展趋势的假设是发达国家市场已经饱和,因此销售量增长应该来自发展中国家初次使用手机的新用户.但后来市场却以15%～20%的惊人速度强势增长,从而在2005年全球手机销售量达到8亿部,而这种增长并不仅限于极低成本手机市场部分.     

A Multimode Cellular Radio

A flexible, multimode radio transceiver for global system for mobile communications, enhanced data rates for global evolution, and wide-band code-division multiple access is presented. The receiver uses low-IF and direct-conversion concepts with an integrated notch filter to adapt to the different requirements. The polar transmitter includes several innovations to provide a flexible solution that eliminates the external SAW filters traditionally needed.     

卫星回传在蜂窝通信上应用

利用卫星回传在蜂窝通信上的应用正快速成为一个主要的卫星产业的一个支柱。通过使用这项基本业务可以将那些边远地区的人进行联系。随着卫星发展，还开发在需要的区域拓展了电信业务。     

Cellular telemetry by microwaves

A process based on microwave interferometry which allows the determination of the position of a beacon transmitter, and its displacement inside a predefined area is presented. This location is defined in terms of elementary areas of cells.<>     

Localization of Cellular Structures

A technique for the localization of cytoplasmic and nucleic material in Wrights and Wrights-Giemsa strained blood cells is described. The microscopic field of view is first scanned with three different wavelengths of light and then digitized with the aid of a microscopic/vidicon/computer. Each of the three pictures is then converted to a binary color picture by comparison with three calculated clipping levels. The three binary color pictures are then logically combined to generate ``masks' or sets of points which correspond to 1)nucleic points in the picture, 2) cytoplasmic points in the picture, and 3)red-cell points in the picture. The algorithms involved are easy to implement either in hardware or software, and execute very rapidly in either environment.     

细胞光子中医学

从细胞生物学的角度介绍了光子中医学的进展,重点强调中医阴阳原理可以用于细胞光生物调节作用的研究.     

元胞遗传算法的多样性研究

探讨了元胞遗传算法中种群多样性对全局寻优/局部收敛平衡的意义,提出了基于邻域结构内元胞遗传算法的多样性度量方式,并提出了改变遗传算子的元胞遗传算法来维持进化过程种群的多样性,算法将元胞空间网格嵌入到种群空间中,模拟遗传操作在相邻个体之间进行。该算法不仅提高了全局搜索能力,且在维持种群多样性方面有一定优势。