【单选题】
802.11g的两个相邻的工作信道之间的频率间隔为___
A. 5MHz
B. 20MHz
C. 25MHz
D. 40MHz
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答案
A
解析
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相关试题
【单选题】
通过配置，IP PBX能够配置信令流的端口，能够将语音业务___的端口限制在一个较小的区间范围内，以保证能够在防火墙上开放相关的端口，实现穿越
A. 媒体流
B. 信令流
C. SIP协议
D. TCP协议
【单选题】
IP-PBX在安装维护中常见问题定位方式主要有四种，对于定位与路由分析、中继选择等呼叫控制相关的问题，一般需要抓取哪种消息___
A. 日志
B. console消息
C. 网络包
D. telnet下SIP栈消息
【单选题】
某OSN6800环网配置了ODUk 环网保护，现在环上的一段光缆需要进行改造，为了避免在改造的过程中业务频繁反复，需要进行下列哪种操作___
A. 锁定倒换
B. 强制倒换
C. 人工倒换
D. 清除
【单选题】
某网络配置了光线路保护组，主备输入光初始差异值为2dbm，主备输入光差异倒换门限为5dbm，那么出现以下哪种情况会触发倒换___
A. 主用通道光功率－备用通道光功率＝4db
B. 主用通道光功率－备用通道光功率＝－4db
C. 主用通道光功率－备用通道光功率＝－2db
D. 主用通道光功率－备用通道光功率＝2db
【单选题】
网管与网关网元通信采用的是什么协议___，网元之间通信采用（）协议
A. ECC，ECC
B. TCP/IP，FTP
C. TCP/IP，ECC
D. TCP/IP，TCP/IP
【单选题】
在U2000网管系统上数据进行备份，默认的路径___
A. d:\oss\server\var\backup
B. d:\oss\clinet\var\backup
C. d:\oss\serber\var\recoad
D. d:\oss\client\var\recoad
【单选题】
关于路由收敛，以下说法正确的是___
A. 收敛是由于网络变化而引起的变化过程
B. 收敛是发送路由呼叫(hello)报文的过程
C. 收敛是两个路由器将它们的路由表合并成一个的过程
D. 收敛是网络中所有路由表的同步过程，或简单地可以定义为一个路由器对网络变化采取相应措施达到稳定状态的过程
【单选题】
什么是静态路由___
A. 静态路由是手工添加到路由表中的，而不是由路由协议动态更新的updated by a routing protocol
B. 当网络变化时，静态路由总是要重新计算
C. 静态路由是通过别的路由协议学习到后引入得到的
D. 静态路由就是路由器在出厂前就设置好的路由
【单选题】
当今世界上最流行的TCP/IP协议的层次并不是按OSI参考模型来划分的，相对应于OSI 的七层网络模型，没有定义___
A. 物理层与链路层
B. 链路层与网络层
C. 网络层与传输层
D. 会话层与表示层
【单选题】
OLT在___这个字段来给每个ONU分配上行时隙，那么所有的ONU就可以按照一定的秩序发送自己的数据了，不会产生为了争夺时隙而冲突。
A. upstream bandwidth map
B. downstream bandwidth map
C. DBRu
D. GTC
【单选题】
OTN技术中的全功能OTM光传输模块OTM-n.m，其中n表示___，m表示（ ）。
A. 复用的通道数，支持的速率
B. 支持的速率，复用的通道数
C. 传输距离，支持的速率
D. 支持的速率，传输距离
【单选题】
在波分系统中，经过一段距离的传输后，收端信号的光信噪比都会有一定程度的降低，最主要的原因是___
A. 没有使用新型光纤
B. 分波合波器的使用
C. EDFA的使用
D. 光线纤衰减太大
【单选题】
OTN（光传送网，Optical Transport Network），是以___为基础、在光层组织网络的传送网，是下一代的骨干传送网。
A. 波分复用
B. 时分复用
C. 频分复用
D. 以上都不对
【单选题】
SDN网络的本质，简单可以总结为：___
A. 数据包的转发通过动态路由表来控制。
B. 路由设备的控制与转发功能实现了统一
C. 路由设备的控制与转发功能实现了分离
D. 以上均不正确
【单选题】
为更好地开展CDN引入工作，减少现网开发，增加CDN服务节点稳定性，浙江移动自建了以下哪个系统完成与CP对接、内容注入及回源？___
A. 内容运营管理平台
B. 流量管理系统
C. 智能调度系统
D. 内容接入平台
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Napoleon took the gamble of pressing on to Moscow, 448 kilometers away. On September 7, 1812, the French and Russian armies met in fierce battle at Borodino, 112 kilometers west of Moscow. By nightfall, thirty thousand French and forty-four thousand Russians lay dead or wounded on the battlefield.
【简答题】
Again, the Russian army retreated to safety. Napoleon had a clear path to Moscow, but the occupation of the city became an empty victory. The Russians fled their capital. Soon after the French arrived, a raging fire destroyed two-thirds of the city. Napoleon offered a truce to Alexander I, but the Russian czar knew he could bide his time: "We shall let the Russian winter fight the war for us."
【简答题】
Napoleon soon realized he could not feed, clothe, and quarter his army in Moscow during the winter. In October 1812, he ordered his Grand Army to retreat from Moscow.
【简答题】
The French retreat turned into a nightmare. From fields and forests, the Russians launched hit-and-run attacks on the French. A short distance from Moscow, the temperature had already dropped to minus 4 degrees Celsius. On November 3, the winter's first snow came. Exhausted horses fell dead in their tracks. Cannon became stuck in the snow. Equipment had to be burned for fuel. Soldiers took ill and froze to death. The French soldiers dragged on, leaving the dead along every mile.
【简答题】
As the Russian army was gathering its strength, the French had to flee Russia to avoid certain defeat. At the Berezina River, the Russians nearly trapped the retreating French by burning the bridges over the swollen river. But Napoleon, by a stroke of luck, was able to build two new bridges. Thousands of French soldiers escaped, but at the cost of fifty thousand dead. Once across the Berezina, the tattered survivors limped toward Vilna.
【简答题】
Of the six hundred thousand soldiers Napoleon had led into Russia, less than one hundred thousand came back. The weakened French army continued its retreat westward across Europe. Soon, Britain, Austria, Russia, and Prussia formed a powerful alliance and attacked these stragglers. In March 1814, Paris was captured. Napoleon abdicated and went into exile, his empire at an end.
【简答题】
By early 1941, Adolf Hitler, leader of Nazi Germany, had seized control of most of Europe. To the east of Hitler's German empire was the Soviet Union. On June 22, 1941, without a declaration of war, Hitler began an invasion of the Soviet Union that was the largest military land campaign in history. Confident of a quick victory, Hitler expected the campaign to last no longer than three months. He planned to use the blitzkrieg, or "lightning war," tactics that had defeated the rest of Europe. The invasion had three broad thrusts: against Leningrad and Moscow and through the Ukraine.
【简答题】
Caught off guard by the invasion, Soviet leader Joseph Stalin instructed the Russian people to "scorch the earth" in front of the German invaders. Farms and factories were burned, destroyed, or rendered useless. During the first ten weeks of the invasion, the Germans pushed the front eastward, and the Russians suffered more than a million casualties.
【简答题】
In the north, the Germans closed in on Leningrad. Despite great suffering, however, the people of Leningrad refused to surrender. As the battle of Leningrad dragged on into winter, the city's situation became desperate. As food ran out, people died from hunger and disease. By the middle of the winter of 1941-1942, nearly four thousand people starved to death every day. Close to one million people died as a result of the siege.
【简答题】
In the center of Russia, Hitler's goal was the capture of Moscow. Because the Germans had anticipated a quick victory, they had made no plans for winter supplies. October arrived with heavy rains. "General Mud" slowed down the movement of the Germans' lightning attack.
【简答题】
As Hitler's armies drew closer and closer to Moscow, an early, severe winter settled over the Soviet Union, the harshest in years. Temperatures dropped to minus 48 degrees Celsius. Heavy snows fell. The German soldiers, completely unprepared for the Russian winter, froze in their light summer uniforms. The German tanks lay buried in the heavy snowbanks. The Russian winter brought the German offensive to a halt.
【简答题】
By the summer of 1942, Hitler had launched two new offensives. In the south, the Germans captured Sevastopol. Hitler then pushed east to Stalingrad, a great industrial city that stretched for 48 kilometers along the Volga River. Despite great suffering, Soviet defenders refused to give up Stalingrad.
【简答题】
In November 1942, the Russians launched a counterattack. With little or no shelter from the winter cold in and around Stalingrad, German troops were further weakened by a lack of food and supplies. Not until January 1943 did the Germans give up their siege. Of the three hundred thousand Germans attacking Stalingrad, only ninety thousand starving soldiers were left. The loss of the battle for Stalingrad finally turned the tide against Hitler. The German victories were over, thanks in part to the Russian winter.
【简答题】
During 1943 and 1944, the Soviet armies pushed the German front back toward the west. In the north, the Red Army broke the three-year siege of Leningrad with a surprise attack on January 15, 1944. Within two weeks, the heroic survivors of Leningrad saw their invaders depart. By March 1944, the Ukraine farming region was again in Soviet hands. On May 9, 1944, Sevastopol was liberated from the Germans. The Russians were now heading for Berlin.
【简答题】
For Hitler, the invasion of the Soviet Union had turned into a military disaster. For the Russian people, it brought unspeakable suffering. The total Soviet dead in World War II reached almost 23 million.
【简答题】
The elements of nature must be reckoned with in any military campaign. Napoleon and Hitler both underestimated the severity of the Russian winter. Snow, ice, and freezing temperatures took their toll on both invading armies. For the Russian people, the winter was an icy defender.
【单选题】
病媒生物的死体样本运送，如果4h-24h内能到达实验室的，应将样品置于-30℃冷冻后再送样，运送过程中箱内温度应保持在________。___
A. 4℃以下
B. 0℃以下
C. -20℃以下
D. 4℃以上
【单选题】
对于用作虫媒病毒分离或检测的蚊类标本，现场采集后应采用_______方式处置和运送。___
A. 杀虫剂熏杀+常温运输
B. 等蚊虫自然死亡+常温运输
C. 冷冻处死+常温运输
D. 冷冻处死+冷冻状态运输
【单选题】
截获输入性活鼠或来自鼠疫流行区死鼠及经总署专家组确认和复核属于全国口岸首次截获的病媒生物应在______报告总署。___
A. 2小时之内
B. 8小时之内
C. 12小时之内
D. 24小时之内
【单选题】
入境船舶的蚊类和蝇类等双翅目病媒生物监测调查应白天在检疫锚地停泊期间进行，锚位距陆地距离不少于______，或在船舶靠泊后_____内进行。___
A. 1000 m；1h
B. 800 m、2 h
C. 400 m、4 h
D. 100 m、24 h
【单选题】
在国境口岸或者交通工具上发现______有反常死亡或者死因不明的，国境口岸有关单位或者交通工具的负责人，必须立即向卫生检疫机关报告，迅速查明原因，实施卫生处理。___
A. 蚊类
B. 鼠类
C. 蝇类
D. 蜚蠊
