问题 单项选择题

WLANs are increasingly popular because they enable cost-effective connections amongpeople, applications and data that were not possible, or not cost-effective, in the past.For example, WLAN-based applications can enable fine-grained management of supply and distribution ___24___ to improve their efficiency and reduce ___25___. WLANs can also enable entirely new business processes. To cite but one example, hospitals are using WLAN-enabled point-of-care applications to reduce errors and improve overall ___26___ care.WLAN management solutions provide a variety of other benefits that can be substantial but difficult to measure. For example, they can protect corporate data by preventing ___27___ through rogue access points. They help control salary costs, by allowing IT staffs to manage larger networks without adding staff. And they can improve overall network management by integrating with customers’ existing systems, such as OpenView. Fortunately, it isn’t necessary to measure these benefits to justify investing in WLAN management solutions, which can quickly pay for themselves simply by minimizing time-consuming ___28___ and administrative chores.

25()

A.personnel 

B.expenses 

C.overhead 

D.hardware

答案

参考答案:C

判断题
实验题

(每空2分,共18分)现有A、B、C、D、E五种物质,并存在如下转化关系.其中E为黑色粉末,在下图转化中均作催化剂

(1)B的化学式          

(2)利用下图所示的实验装置进行C与水的反应,回答下列有关同题:

①      固体C与水反应生成D的化学方程式为:                                  

②      检验导管出口气体的方法为:                                     

③烧杯中的现象为:                       

(3)在加热条件下,某无氧酸(含有A中的一种元素)的浓溶液与E反应,生成单质气体X.为检验X的性质,设计如下图所示实验装置:

①实验过程中,观察到装置Ⅲ中的品红试纸的红色褪去,并未观察到“无明显变化”这一预期现象.为了达到这一预期现象,你认为应该如何改进?

                                                                           

②实验结束后,装置Ⅳ中可观察到现象是             ,若滴加两滴胶头滴管中的试剂,观察到溶液呈血红色,有关的离子方程式为:

                                 ,                   

③X是一种重要的化工原料,用化学方程式表示X在化工生产上的一项用途:

                                                                         。