【单选题】
电弧焊是利用电弧热源加热零件实现___焊接的方法。焊接过程中电弧把电能转化成热能和机械能,加热零件,使焊丝或焊条熔化并过渡到焊缝熔池中去,熔池冷却后形成一个完整的焊接接头。(中)
A. 热能
B. 物理
C. 化学
D. 熔化
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答案
D
解析
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相关试题
【单选题】
焊条电弧焊是用手工操纵___进行焊接的一种焊接方法,俗称手弧焊,应用非常普遍。(难)
A. 机器
B. 焊条
C. 焊枪
D. 焊钳
【单选题】
焊接过程中,产生在焊条和零件之间的___将焊条和零件局部熔化,受电弧力作用,焊条端部熔化后的熔滴过渡到母材,和熔化的母材融合一起形成熔池,随着焊工操纵电弧向前移动,熔池金属液逐渐冷却结晶,形成焊缝。(中)
A. 电弧
B. 温度
C. 压力
D. 气体
【单选题】
焊接时,焊芯有两个功能:一是传导焊接电流,产生电弧;二是焊芯本身熔化作为填充金属与熔化的母材熔合形成___。(难)
A. 焊缝
B. 焊渣
C. 焊皮
D. 焊接
【单选题】
焊条药皮又称涂料,在焊接过程中起着极为重要的作用。它可以起到积极保护作用,利用药皮熔化放出的气体和形成的___,起机械隔离空气作用,防止有害气体侵入熔化金属。(中 )
A. 焊缝
B. 熔渣
C. 焊皮
D. 焊接
【单选题】
焊条药皮的组成主要有稳弧剂、造气剂、造渣剂、脱氧剂、合金剂、粘接剂和___等。( 易 )
A. 增塑剂
B. 增强剂
C. 硬化剂
D. 塑化剂
【单选题】
焊条电弧焊有两种引弧方式:划擦法和___法。( 难 )
A. 点击
B. 横击
C. 直击
D. 斜击
【单选题】
焊条电弧焊是依靠人手工操作焊条运动实现焊接的,此种操作也称___。(中)
A. 手焊
B. 自动焊
C. 运焊
D. 运条
【单选题】
常见的焊条电弧焊运条方法有___种。(易)
A. 5
B. 6
C. 7
D. 8
【单选题】
为不影响焊缝成形,保证接头处焊接质量,更换焊条的动作越快越好,并在接头弧坑前约 ___ mm处起弧,然后移到原来弧坑位置进行焊接。(中)
A. 15
B. 16
C. 17
D. 18
【单选题】
焊缝的收尾操作时,应保持正常的熔池温度,做无直线运动的横摆点焊动作,此外还有三种焊缝收尾的操作方法,即___收尾法、反复断弧收尾法和回焊收尾法,也在实践中常用。(难)
A. 划圈
B. 直线
C. 横线
D. 点划
【单选题】
在实际生产中,由于焊接结构和零件移动的限制,焊缝在空间的位置除平焊外,还有立焊、横焊、仰焊。其中焊接条件___位置最差。(中)
A. 仰焊
B. 横焊
C. 立焊
D. 平焊
【单选题】
电弧焊机行走机构:是使焊接机头和零件之间产生一定速度的相对运动,以完成___焊接过程的机械装置。(中)
A. 整个
B. 手动
C. 自动
D. 全部
【单选题】
接头形式电阻焊可分成点焊、缝焊、凸焊和___四种。(中)
A. 对焊
B. 面焊
C. 凹焊
D. 线焊
【单选题】
缝焊一般应用在有密封性要求的接头制造上,适用材料板厚为___ mm,如汽车油箱、暖气片、罐头盒的生产。(难)
A. 0.1~0.02
B. 0.1~0.2
C. 0.1~2
D. 0.1~20
【单选题】
工件焊后一般都会产生变形,如果变形量超过___值,就会影响使用。( 中 )
A. 标准
B. 一定
C. 允许
D. 误差
【单选题】
焊接变形产生的主要原因是___不均匀地局部加热和冷却。(中)
A. 材料
B. 焊件
C. 钢材
D. 焊条
【单选题】
焊接产生拉应力和压应力,当这些应力超过金属的___极限时,将产生焊接变形;当超过金属的强度极限时,则会出现裂缝。(难)
A. 屈服
B. 抗拉
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【单选题】
焊瘤对静载强度无影响,但会引起应力集中,使___强度降低。(难)
A. 抗拉
B. 动载
C. 动静
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【单选题】
焊缝的外部缺陷五种:焊缝增强过高,焊缝过凹,焊缝咬边,___,烧穿。(难)
A. 焊缝开裂
B. 焊缝过高
C. 塌陷
D. 焊瘤
【单选题】
焊缝中熔入过多的___,也会引起冷裂纹。(难)
A. 氢
B. 氧
C. 碳
D. 氮
【单选题】
焊接质量的检验包括___试验三个方面。这三者是互相补充的,而以无损探伤为主。(中)
A. 外观检查、无损探伤和仪器检测
B. 内观检查、无损探伤和机器检测
C. 外部检查、无损探伤和机械性能
D. 内部检查、无损探伤和机械性能
【单选题】
___目前使用最普遍的是采用X射线检验,还有超声波探伤和磁力探伤。
A. 无损探伤
B. 外观检查
C. 仪器检测
D. 机器检测
【单选题】
焊条电弧焊是利用焊工眼睛、脑、手配合适时调整弧长,电弧焊自动调节系统则应用___控制系统进行调节。(中)
A. 开环
B. 闭环
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【单选题】
CO2 气体保护焊工艺具有生产率___、焊接成本低、适用范围广、低氢型焊接方法焊缝质量好等优点。( 易 )
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CO2 气体保护焊设备可分为___焊和自动焊两种类型。(中)
A. 半自动
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列车及调车作业中发生冲突、脱轨、火灾、爆炸、相撞,造成客运列车耽误本列1小时以上为___事故。
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列车及调车作业中发生冲突、脱轨、火灾、爆炸、相撞,造成客运列车中途摘车1辆为___事故。
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关闭折角塞门发出列车或运行中关闭折角塞门为___事故。
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作业人员违反劳动纪律、作业纪律耽误列车为___事故。
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C. 一般C类
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行车设备故障耽误本列客运列车1小时以上___事故。
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B. 一般B类
C. 一般C类
D. 一般D类
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DC600V供电列车中机车每路输出功率为___kW。
A. 300
B. 350
C. 400
D. 450
【单选题】
电力机车牵引区段每 ___ km 存在分相区,过分相区时,受电弓失电。
A. 25
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下列电路中___不是逆变器的主电路?
A. 输入/输出隔离电路
B. 中间支撑电路
C. 降压电路
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由于断电后,逆变器单元内的储能器件(电容、电感)不可能立即就放电完全,因此,必须在断电___分钟后方可开始检修。
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逆变器在通控制电路情况下每个传感器都是___V供电。
A. 110
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DC600V供电客车控制柜触摸屏中进入“管理界面”的密码为___。
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DC600V电源漏电保护值出厂时预设为___mA。
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习惯上人们规定正电荷移动的方向为___的方向。
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电路中任意两点之间的电位差称为这两点间的___。
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电路都由___、负载、中间环节等组成。
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推荐试题
【多选题】
Which statement about the communication between interfaces on the same security level is true?___
A. Interfaces on the same security level require additional configuration to permit interinterface communication
B. Configuring interfaces on the same security level can cause asymmetric routing
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【多选题】
In which two situations should you use in band management? ___
A. when the control plane fails to respond
B. when you require administrator access from multiple locations
C. when you require ROMMON access.
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【多选题】
Which two features are supported in a VRF-aware softwar infrastructure before VRF-lite?___
A. multicast
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D.
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【多选题】
.Which loS command do you enter to test authentication again a AAA server?___
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【多选题】
Which two statements about the self zone on a cisco Xone based policy firewall are true?___
A. Multiple interfaces can be assigned to the self zone
B. it supports stateful inspections for multicast traffic
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D. it can be either the source zone or the destination zone
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【多选题】
Which type of attack can exploit design flaws in the implementation of an application without ?___
A. DHCP starvation attacks
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【单选题】
Which type of firewall can server as the interme diary between a client and a server ?___
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【单选题】
What is the highest security level that can be configured for an interface on an ASA?___
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C. 10
D. 200
【单选题】
Which term refers to the electromagnetic interference that can radiate from network cables?___
A. Gaussian distributions
B. Doppler waves
C. emanations
D. multimode distortion
【单选题】
How does a zone pair handle traffic if the policy de fination of the zone pair is missing?___
A. It inspects all traffic.
B. It drops all traffic.
C. It permits all traffic wihtout logging
D. It permits and logs all traffic
【单选题】
default how does a zone based firewall handle traffic to add from the self zone?___
A. It permits all traffic without inspection
B. It inspects all traffic to determine how it is handled
C. It permits all traffic after inspection
D. It frops all traffic
【单选题】
Which command should beused to ena ble AAA Authentication to determine if a user can access the privilege command level?___
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B. aaa authentication enable level=
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D. aaa authentication enable defa ult local
【单选题】
On an ASA, the policy indicates that traffic should not be translated is often referred to as which of the following?___
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【单选题】
Which protocol offers data Integrity encryption, authentication, and anti-replay functions for IPSec VPN?___
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Which component offers a variety of security Solution, including firwall, IF Antivirus and antiphishing features?___
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Refer to the exhibit, A Network Secur ity administrator check the ASa firewall NAT policy table rith show nat command, which statement is fails?___
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【单选题】
What is true of an aSa in transparent mode ?___
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What is the effect of the ip scp server enable command?___
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【单选题】
How can you mitigate attacks in which the attacker attaches more than one vLan tag to a packet?___
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D.
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Which technology can you implement to centrally mitigate potential threats when users on your network download files that might be malicious?___
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【单选题】
What is the most common implementation of PaT in a standard networked environment?___
A. configuring multiple external hosts to join the self zo ne and to communicate with one another
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Which component of a bYod architecture provides aAa services for endpoint access ?___
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You are configuring a NAT rule on a Cisco ASA ,Which description of a mapped interface is true?___
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Which description of the use of a private key is true ?___
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【单选题】
Which mechanism does the FireAMP Connector use to avoid conflicts with other security applications such as antivirus products ?___
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D.
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【单选题】
Which network to pology de scribes multiple LANS in a gec? ___
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【单选题】
Which statement represents a difference between an access list on an aSa versus an access list on a router?___
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【单选题】
Which command do you enter to verify the status and settings of an iKE Phase 1 tunnel?___
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【单选题】
Which feature can help a router or switch maintain packet forwarding and protocol states despite an attack or heavy traffic load on the router or switch?___
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F. orwarding
【单选题】
Which STP feature can prevent an attacker from becoming the root bridge by immediately shutting down the interface when it receives a BPDU?___
A. root guard
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【单选题】
Which technology can best protect data at rest on a user system?___
A. full-disk encryption
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【多选题】
Which two primary security concerns can you mitigate with a BYOD solution ?___
A. schedule for patching the device
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【多选题】
choose five___
A. MD5————————inserure
B. DES————————insercure
C. SDES———————legacy
D. SHA-1———————legacy
E. HMAC-MD5—————legacy
【多选题】
Which two characteristics of symmetric encryption are true?___
A. It uses digital certificates
B. It requires more resources than asymmetric ancryption
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E. It is faster than asymmetric encryption
【多选题】
which two characteristics of PVLAN are true?___
A. Promiscuous porta can communicate with PVLAN ports.
B. Isolated ports cannot communicate with other ports on the same VLAN
C. Community ports have to be a part of the trunk.
D. They require VTP to be enabled in server mode
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【多选题】
What are two options for running Cisco SDM?___
A. Running SDM from a mobile device
B. Running SDM from within CiscoWorks
C. Running SDM from a router's flash
D. Running SDM from the Cisco web porta
E. Running SDM from a PC
【多选题】
Which two options are the primary deployment modeles for mobile device management?___
A. multisite
B. cloud-based
C. on premises
D. hybrid cloud basedo
E. single site
【多选题】
Drag the recommendation on the left to the Cryptographic algorithms on the right, Options will be used more than once.___
A. Avoid——————————————DES,MD5
B. Legacy——————————————SDES,SHA1,HMAC-MD5
【多选题】
Which two are valid types of vLans using PVLANS ?___
A. Community VLAN
B. Backup VLAN
C. Secondary VLAN
D. Isolated VLAN
E. Isolated VLAN
【多选题】
Which two commands are used to implement Resilient lOS Configuration ___
A. Secure boot-config
B. copy running-config tftp
C. copy flash:ios bin tftp
D. copy running-config startup-config
E. secure boot-image