旅馆里的语言处理系统

旅馆里的语言处理系统近年来，为了提高旅馆的服务水平，争取更多的宾客，旅馆开始引人语言处理系统。最普遍的一种服务是宾客的个人邮箱。宾客可利用其房间的电话留言，留言可以是任何种语言。当宾客外出时，打进来电话的留言可在旅馆房间里或旅馆外的某一部话机听到留言...     

香港电信(HKT)将推出回叫业务

为了与电话回叫业务相竞争,香港电信(HKT)将推出其自己的回叫业务。该0060国际电话回叫业务包括了北美、日本、台湾等业务较多的12个国家和地区,其费率将比HKT自己的IDD 001业务低。HKT对国际长途电话(IDD)     

4G在悄然兴起

根据GSM协会的统计,今年全球约将有40个新的3G(第三代移动通信)W-CDMA系统开始逐步进入市场.与此同时,4G(第四代移动通信)正悄然兴起.例如,日本的公众管理,家庭事务,邮政和电信部已计划在2005年开发4G,并于2010年商用化.韩国也有类似的计划.印度信息技术部于2002年成立了专门的部门,打算用三年的时间研制包括用户终端在内的4G无线标准……此外,由lcatel,Ericsson,Nokia和Siemens等公司组成的全球无线研究论坛(WWRF)于2001年初就开始着手研究制订4G的相关策略,其成员们也承担了相应的课题研究.     

细粒分级水力旋流器及其网络的设计与模拟

利用建立的三函为数对称通解的转换定理，系统地构造出了一系统二函数轴对称通解，本文的方法是由作者前所提出的三维通解方法演变而来，故它可沟通从三维弹性力学通解蜕化成二函数轴对称通解的渠道，并将整个弹性力学位移通解（三维和二维）融合于一体之中，所论及的通解都是完备的，不以子午面单连通或ｚ向凸的条件为前提。     

LTV钢公司连续退火线的计算机集成制造

计算机集成制造设备是能够在不到１０ｍｉｎ时间内完成优质成品板卷的一个关键设备，该生产过程包括退火、光整冷轧、侧修边剪、检查和准备发货，采用常规的精整设备来完成这一系列生产过程需要１０天时间。     

Nonmonotonic behavior of the maximum collapse pressure in a cavitation bubble

Calculations which are relevant to the determination of the maximum collapse pressure generated inside a microbubble as a function of peak pressure in the driving ultrasonic pulse are presented. It is found that above the threshold for transient cavitation, the maximum collapse pressure has a nonmonotonic variation. This result is explained on the basis of phase differences between the external applied acoustic pulse and the resulting bubble response.     

A Realistic Computer-Simulated Brain Phantom for Evaluation of PET Charactenstics

To evaluate accurately the imaging characteristics of positron emission tomography (PET), a realistic computer-simulated brain phantom was developed. A cross-sectional slice from a human cadaver brain was chosen for its combination of gray matter, white matter, and cerebrospinal fluid (CSF) regions. The slice was photographed and digitized into a gray-level image with a video digitizer, boundary edges were located around cerebral structures in the digitized image, and each structural region was assigned a uniform pixel value dependent on both the cerebral parameter (e.g., blood flow, oxygen uptake, metabolic rate) under investigation and the type of structure (gray matter, white matter, CSF). Line integrals through the regions were generated at various angular and transverse positions according to specific physical characteristics (such as detector line-spread function) of a tomographic scanner configuration to create a set of simulated but realistic projection measurements. The set of projection measurements can be processed with any standard reconstruction program to create a tomographic image to reveal the effects of various PET characteristics. Investigations with this computer-simulated brain phantom have demonstrated its usefulness for examining the interrelations among neuroanatomical structure volume, tomographic spatial resolution, partial volume effect, and nonlinear parameter estimation. Transportability of the simulated phantom and the procedure to other medical imaging environments is described, and limitations of this simulation procedure are discussed.     

Unique phospholipid metabolism in mouse heart in response to dietary docosahexaenoic or α-linolenic acids

Diet and fatty acid metabolism interact in yet unknown ways to modulate membrane fatty acid composition and certain cellular functions. For example, dietary precursors or metabolic products of n-3 fatty acid metabolism differ in their ability to modify specific membrane components. In the present study, the effect of dietary 22∶6n−3 or its metabolic precursor, 18∶3n−3, on the selective accumulation of 22∶6n−3 by heart was investigated. The mass and fatty acid compositions of individual phospholipids (PL) in heart and liver were quantified in mice fed either 22∶6n−3 (from crocodile oil) or 18∶3n−3 (from soybean oil) for 13 wk. This study was conducted to determine if the selective accumulation of 22∶6n−3 in heart was due to the incorporation of 22∶6n−3 into cardiolipin (CL), a PL most prevalent in heart and known to accumulate 22∶6n−3. Although heart was significantly enriched with 22∶6n−3 relative to liver, the accumulation of 22∶6n−3 by CL in heart could not quantitatively account for this difference. CL from heart did accumulate 22∶6n−3, but only in mice fed preformed 22∶6n−3. Diets rich in non-22∶6n−3 fatty acids result in a fatty acid composition of phosphatidylcholine (PC) in heart that is unusually enriched with 22∶6n−3. In this study, the mass of PC in heart was positively correlated with the enrichment of 22∶6n−3 into PC. The increased mass of PC was coincident with a decrease in the mass of phosphatidylethanolamine, suggesting that 22∶6n−3 induced PC synthesis by increasing phosphatidylethanolamine-N-methyltransferase activity in the heart.