门静脉高压症的病理变化中，下列哪项是错误的A．毛细血管滤过压增加，腹水形成 B．肝功

什么是心理输导服务？

振兴农业机械厂接受的陈某交给的100吨钢材应如何处理

从供选择的答案中选出应填入下列叙述中( )内的正确答案：
数据库系统是由(A) 、(B) 、(C) 和软件支持系统组成，其中(A) 是物质基础，软件支持系统中(D) 是不可缺少的，(B) 体现数据之间的联系，(C) 简称DBA。常见的数据模型有多种， 目前使用较多的数据模型为(E)模型。
供选择的答案
A～D：①计算机硬件 ②C语言 ③CPU ④数据库管理系统
⑤数据库 ⑥主菜单 ⑦人 ⑧网络管理系统
E：①层次 ②网状 ③关系 ④拓朴

Current Group, a Germantown-based technology firm, has taken over an ordinary looking house in Bethesda and turned it into a laboratory for smart-grid technology, the system the company believes will bring the nation’s electricity grids into the digital age.

In the front yard stands a utility pole hooked up to a special transformer that connects the power lines to high-speed Internet. Hundreds of sensors attached to the lines monitor how power flows through the home. That information is then sent back to the utility company.

The process lets a utility more efficiently manage the distribution of electricity by allowing two-way communication between consumers and energy suppliers via the broadband network on the power lines. Based on data they receive from hundreds of homes, utilities can monitor usage and adjust output and pricing in response to demand. Consumers can be rewarded with reduced rates by cutting back on consumption during peak periods. And computerized substations can talk to each other so overloaded circuits hand off electricity to those that have not fully loaded, helping to prevent blackouts.

Some utility companies have launched initiatives to give consumers data about their energy consumption habits in an effort to lower energy bills. Smart-grid technology takes such programs further by automating electricity distribution, which would make grids more reliable and efficient.

By partnering with utilities, the company hopes to tap into $4.5 billion in stimulus grants intended to encourage smart-grid development. When he announced the funding, President Obama pointed to a project in Boulder, Colo. , as an example of a successful smart-grid experiment. Current is one of the companies working on the project.

Current’s chief executive Tom Casey believes the technology will help utility companies better distribute electricity produced by renewable resources, such as solar panels or wind farms. " A smart grid’s system can be paired up with the renewable resources so that when the renewable source is varying, the overall load can be varied as well, " Casey told the House Select Committee on Energy Independence and Global Warming. " This will reduce or eliminate the need for backup coal or gas-based power generation plants. \

Why is the system called " smart-grid " technology（）

A. Because with all the sensors and transformers, the equipment looks very modern

B. Because with all the data, they can help the utilities make clever decisions

C. Because the technology is making good use of computer intelligence

D. Because the consumers can have wise ideas on the usage of electricity

化工生产的不安全因素？