【判断题】细菌性的食物中毒是比较常见的一种食物中毒类型,根据中毒的原因可将其分为感染性食物中毒和毒素性食物中毒。
【简答题】某化合物的分子式为C6H10O,1HNMR谱和IR谱图分别如图4—37和图4—38所示,推断它的结构。 IR谱图出峰位置和透过率:
【简答题】某化合物分子式为C5H9NO,其1HNMR谱和IR谱图分别如图4—28和图4—29所示,推断它的结构。 IR谱图出峰位置和透过率:
【简答题】试推测下面两个图哪个是2,2-二甲基戊烷的IR谱图,哪个是2-甲基丁烷的IR谱图。
【简答题】某化合物分子式为C5H9NO,其1HNMR谱和IR谱图分别如图4—26和图4—27所示,推断它的结构。 IR谱图出峰位置和透过率:
【单选题】How does the ERX Edge Router interact with an external DHCP server in a Bridged 1483 network?()
A.
It maintains DHCP leases on behalf of subscribers.
B.
It initiates DHCP requests on behalf of subscribers.
C.
It passes DHCP traffic to and from the server;you must configure static host routes.
D.
It passes DHCP traffic to and from the server and inserts host routes into its routing table.
【简答题】某化合物的分子式为C6H10O,1HNMR谱和IR谱图分别如图4—35和图4~36所示,推断它的结构。 IR谱图出峰位置和透过率:
【单选题】How does a DHCP server dynamically assign IP addresses to hosts?
A.
Addresses are permanently assigned so that the host uses the same address at all times
B.
Addresses are assigned for a fixed period of time. At the end of the period, a new request for an address must be made, and another address is then assigned.
C.
Addresses are leased to hosts. A host will usually keep the same address by periodically contacting the DHCP server to renew the lease.
D.
Addresses are allocated after a negotiation between the server and the host to determine the length of the agreement.