pws:个人网站服务器-中文百科频道

服务器名称

概述

PWS 全称为 Personal Web Server，是微软开发的个人网站服务器，主要应用于解决个人信息共享和 Web 开发。它是一个桌面形的 Web 服务器，使用它可以自动创建个性化主页，以拖放的方式发布文档，在它的帮助下，我们可以快速简便地进行 Web 站点设置。

介绍

引用部分微软的话就是：

“...在企业 Intranet 上，Personal Web Server 可用于以自身的格式快速共享文档，或者将文档转换为 HTML，然后使用 PWS 在不同的操作系统共享这些文档。”

“由于 Personal Web Server 支持 Active Server Pages，因此可以作为 Web 站点的开发和测试平台。在企业服务器上或 Internet 服务提供商处使用您的站点前，可以先在办公室或家里创建站点，并使用 Personal Web Server 进行测试。

病症名称

概述

普达-威利综合症英文全称为Prader-Willi syndrome，为一种一种罕见疾病，目前证实为15号染色体缺失所致,属于遗传疾病致范畴。

临床表现

患者表现为饥饿,且不能因进食而消除饥饿感，致使患者暴饮暴食。有时患者会出现吃猫粮狗粮，甚至煤等不是食物的物品进行“充饥”。由于长期

的暴饮暴食患者表现为病态肥胖。同时患者可伴有智力低下及其它异常。

治疗

该病尚无药物治疗，只能通过控制饮食，加强锻炼来对抗疾病。抑制食欲的药物对该病无效。若不能有力的控制食欲，患者常因体重超标而引起的各种疾病而英年早逝。

系统名称

概述

PWS：风切变预警系统

英文全称为Predictive Windshear System

PWS

详细介绍

现在飞机的气象雷达大多都加装了PWS预测风切变功能。飞机的GPWS 近地警告系统也提供低空风切变警告。判断原理是多普勒频移原理。飞机顶风产生正的多普勒频移，顺风产生负的多普勒频移，如果在一个很短的距离内探测到明显的正负风速变化，则可判断为风切变。机组得到风切变警告后需立即采取措施，比如停止近进，复飞，风切变机动飞行，来躲开风切变。起飞和复飞时，飞机的自动驾驶系统会提供飞行指引，帮助机组进行正确的俯仰操作。进近时，如果遭遇严重风切变，机组应该脱开自动驾驶，进行人工飞行，否则有可能失速。不操纵飞机的驾驶员要密切监视垂速表和高度表，机组的快速反应和清醒的意识是非常重要的。

英文介绍

Windshear is a sudden, rapid change in wind velocity or direction. It is often found in –– but is not limited to –– thunderstorms or other highly unstable atmospheric events.

The most dangerous form of windshear is known as microburst, a vertical column of air rapidly descending toward the ground.

Upon reaching the ground, microburst spreads out horizontally, creating a horizontal outflow.

Entering a microburst is very dangerous for an airplane because the wind may be strong enough to overcome the maximum of climb performance.

Known as the Predictive Windshear System (PWS), this technology permits weather radar systems to scan the atmosphere ahead of an airplane and detect windshear before the airplane enters it.

Predictive Windshear System (PWS)

The Principle ofPWS

PWS

uses wind velocity data gathered by a Doppler weather radar system to identify the existence of a windshear.

Radar energy is emitted through the airplane's radome in order to gather atmospheric information such as wind speed and direction. The weather radar receiver/transmitter then uses this information, in addition to air data and inertial data, to determine the presence of a windshear.

The weather radar processor identifies wind velocity characteristic that indicate a rapid change in wind velocity or direction over a relatively small area. When the magnitude of the detected windshear reaches a predetermined intensity level, the system alerts the flight crew.

If thePWS

detects a windshear from a significant distance, the flight crew may be able to avoid it completely. If windshear is unavoidable, however,PWS

gives the flight crew valuable time to increase speed or altitude before the airplane enters a windshear.

The Principle ofPWS

PWSprovides windshear detection with very few operational changes that will affect flight crews.

First, the flight crew does not need to manually turn on the weather radar for it to operate in the windshear mode.

If not already turned on by the flight crew, the radar automatically turns on at 2,300 feet (700m) above ground level (AGL) for approach and landing coverage.

The radar also turns on automatically before takeoff—using air-ground and takeoff thrust logic—to provide windshear coverage during takeoff roll, rotation, and climbout.

The flight crew can manually activatePWS

on the ground by turning on the weather radar. The automatic activation ofPWS

does not affect the weather radar display; it will remain in the mode and range selected by the flight crew.

The Principle ofPWS

The PWS automatically sets weather radar gain and tilt when in a windshear mode. As a result, it is effective regardless of the settings made by the flight crew on the weather radar control panel.

Crew-selected tilt and gain are used when the radar is in a weather sweep.