题目内容 (请给出正确答案)
提问人:网友f******g 发布时间:2022年5月1日 21:37
[简答题]

分析时为什么要对样品进行预处理?选择预处理方法的原则是什么?

参考答案
十点题库官方参考答案 (由十点题库聘请的专业题库老师提供的解答)
更多“

下列属于边防检查部门主要工作职责的是()
A.征收关税和减免关税
B.拒绝、阻止入出境
C.交通运输工具的检查
D.抵、离口岸人员的入出境检查
点击查看答案
有关总量控制和核定制度的表述,错误的是()
A.有总量控制任务的企事业单位,必须按照核定的主要大气污染物排放总量和许可证规定的排放条件排放污染物
B.我国大气污染物排放目前一总量控制为主
C.总量控制的推行势在必行
D.在实行总量控制的区域实行排污许可并按排放总量核定收费的制度,而不执行一般污染物排放的排污收费制度
点击查看答案
依据《湖南省住宅工程质量通病防治技术规程》DBJ43/T306-2014第4.2.5条,为了保证现浇梁板混凝土强度符合要求,下列做法正确的是()。
A.模板拆除后,楼面施工荷载(含堆载)不得超过楼板承载能力。 B.在楼板上吊装、运输、堆放材料、构件时,应采取措施,减轻对楼板的冲击,并避免集中堆载。 C.外架采用悬挑外架时,对布设悬挑工字钢的楼板,可以直接堆载,不需要进行强度、刚度及局部承载力验算。 D.由施工电梯轿厢进入建筑各楼层的第一个房间楼面,应依据现场实际工况对该楼面强度、刚度进行验算。
点击查看答案
女,25岁,孕1产1,第1胎,产钳助产,产后第4天,产妇自述发热,下腹微痛。查:体温38℃,双乳稍胀,无明显压痛,子宫脐下2指,轻压痛,恶露多而混浊,有臭味,余无异常发现本例最主要的病原菌应是()
A . A.金黄色葡萄球菌
B . 类杆菌属
C . β-溶血性链球菌
D . 沙眼衣原体
E . 厌氧革兰阳性球菌
点击查看答案
Summer was, for a while, a child"s time, conferring an inviolate right to laziness. It was a form of education that had nothing to do with adult priorities, providing entire afternoons to watch exactly how many ants would dash out of one hill and what they would bring back. The holiness of that kind of summer was first diminished by necessity, when overcrowded classrooms brought us the year-round school calendar. Next, the battle against social promotion forced many an indifferent student into summer school—while the hard-charging students willingly packed into summer school as well, to get a leg up on the coming year. Then, as though the world of achievement had some sort of legitimate claim on summer, even schools that maintained the old-fashioned schedule began reaching their tentacles into summer. Some school districts start the traditional school year in August, the better to squeeze in a couple of more weeks of instruction before the all-important state standardized tests given in spring. Worse, what used to be recommended summer reading lists are now becoming compulsory assignments. And woe to the ambitious student who"s signed up for Advanced Placement classes, and thus a summer-load of note taking and homework. It"s not just the schools. As a society, we growitchyat the sight of someone—even a kid-accomplishing nothing more than fun. Thus parents have become suckers for anything that lends a constructive air to summer. Summer camps used to exist for the purpose of marshmallow roasts and putting frogs in your bunkmates" beds. Those still exist, but they compete mightily with the new camps— the ones for improving a child"s writing style, building math skills, honing soccer stardom, learning a foreign language, building dance talents or finessing skills playing a musical instrument. Even many colleges and universities, such as Johns Hopkins, have climbed on board, mailing out silky brochures about their expensive summer programs for supposedly gifted, or at least financially gifted, students. None of this activity is required, of course. Unluckily, other societal changes also have pushed back at summer. Children can"t get together a pickup game of kickball when their streets are the turf of gangs. And without a shove out the door, today"s youngsters are more likely to spend a day clicking away at video games than swinging in a hammock. Still, it is a decision, however unconsciously made, to view summertime as a commodity to be prudently invested, rather than as a gift to be lavishly spent. There is only one sort of skill we are afraid to nurture in our kids—the ability to do nothing more constructive than make a blade of crabgrass, pressed between our thumbs and blown, blast a reedy note into the summer air.
A.a satisfying investment.B.a precious present.C.a remarkable experience.D.a well-planned journey.
点击查看答案
女,18岁。右颌下区肿痛7天,加剧3天,查体见:T39℃,一般情况差,右颌下皮肤红,皮温高,压痛明显,触有波动感,肿胀无明显界限。口内:舌下肉阜无红肿,导管口无溢脓,右下第一磨牙残根,叩痛(++),x线片见6限尖周x线透射区。穿刺颌下区最可能抽出的液体是()
A . 黄色粘稠脓液
B . 暗灰色稀薄脓液
C . 陈旧性血性液体
D . 黄色蛋清样液体
E . 淡黄色清亮液体
点击查看答案
测定二灰稳定碎石基层压实度,应优先采用______。
A.环刀法
B.灌砂法
C.蜡封法
D.核子密度仪法
点击查看答案
甲、乙、丙、丁四人设立一家合伙企业,并约定委托丁执行合伙企业事务。在该合伙企业存续期间,下列各项中须经全体合伙人一致同意的事项是( )。
A.合伙人乙以其在合伙企业中的部分财产份额出质
B.合伙人丙向合伙人乙转让其在合伙企业中的全部财产份额
C.执行合伙企业事务的合伙人丁聘任合伙人甲担任合伙企业的经营管理人员
D.合伙人甲以劳务形式出资
点击查看答案
麻风的“风”是指()
A.畸残
B.症状
C.病因
D.传染
点击查看答案
电动机的选择包括电动机的种类、结构形式、()和()。
点击查看答案
员工参加由单位安排的职业健康检查、复查、医学观察、诊断和治疗所占用的工作时间,应视为正常出勤。
点击查看答案
Cultural Shock "Culture shock" might be called an occupational disease of people who have been sudd...According to the passage, what is the best way to cure him or her when one is experiencing a nervous breakdown because of culture shock
A.Referring him to see a good doctor.
B.Asking him to live with native people.
C.Sending him back to his home culture.
D.Letting him stay with people from his home cultur
点击查看答案
下列不属于第三层交换技术和协议的是()
A.IP组播地址确定 B.IGMP C.ICMP D.DVMRP
点击查看答案
阅读下列材料,结合所学知识回答问题。 材料一政治方面主张统一政令,以法治国;各省设新闻官,听取社会舆论,设投票箱,由公众选举官吏。经济方面,主张学习西方,发展工商业,奖励技术发明,兴办保险事...分别概括三则材料所反映的近代中国三种政治力量及其主要思想理论。
点击查看答案
毛料西服干洗前,先晾晒,用毛刷先把毛料西装上的灰尘轻轻刷掉,然后在用毛刷自上而下轻轻的刷一遍。
点击查看答案
客服
TOP