共查询到20条相似文献，搜索用时 187 毫秒
1.
《时代数学学习》2004,(11)
1.(x- 2 ) (x+4) (x +1 ) (x- 1 ) . 2 .95°. 3 .2 0 . 4 .30°或 1 50°.5 .a≤ - 2 . 6 .2 4或 40 . 7.6或 1 4 . 8.2 0 0 4 . 9.40°. 1 0 .3.1 1 .D . 1 2 .C . 1 3 .B . 1 4 .B . 1 5 .D . 1 6 .A . 1 7.A . 1 8.C .1 9.设第一次看到两位数的十位数字为x,个位数字为 y,根据题意 ,得(1 0y+x) - (1 0x+y) =(1 0 0x +y) - (1 0 y +x) .整理 ,得 y =6x . 显然 ,只能取x=1 ,y=6 .所以 ,三块里程碑上的数分别为 1 6 ,61 ,1 0 6 .2 0 .作AD ⊥BC于D(图略 ) ,在Rt△ADC中 ,∠C =45°,∴∠CAD=45°.∵∠BAC =1 0 5°,∴∠BAD =60°… 相似文献
2.
一 .名词解释 (每题 3分 ,选 1 5分练习 )1 .水中毒 2 .缺氧 3 .心肌抑制因子 4.休克 5.阻塞性通气不足 6.限制性通气不足 7.氮质血症 8.脑死亡 9.离心性心肌肥大 1 0 .急性肾功能衰竭 1 1 .不完全康复 1 2 .充血性心力衰竭 1 3 .呼吸衰竭 1 4.发热 1 5.尿毒症 1 6.病因 1 7.肝性脑病 1 8.因果交替规律 1 9.休克肺二、填空题 (每空 1分 ,选 2 0分练习 )1 .疾病所引起的患者主观感觉的异常称为 ,在患病机体客观存在的异常称为。2 .先天性致病因素是指的因素。3 .急性水中毒时 ,血钠含量 ,细胞内液量 ,对机… 相似文献
3.
《化学教学》2000,(12)
说明 :1 .本答案供阅卷评分使用 ,考生若写出其它正确答案 ,可参照评分标准给分。2 .化学专用名词中出现错别字、元素符号有错误 ,都要参照评分标准扣分。3.化学方程式、离子方程式未配平的 ,都不给分。Ａ卷选择题答案 :一、(本题包括 1 1小题 ,每小题 4分 ,共 4 4分 )1 .Ｄ 2 .Ｂ 3.Ａ 4 .Ａ 5.Ｄ 6.Ｂ 7.Ｃ 8.Ｄ 9.Ｄ 1 0 .Ｃ 1 1 .Ａ二、(本题包括 1 0小题 ,每小题 4分 ,共 4 0分 )1 2 .Ａ、Ｃ 1 3.Ａ、Ｄ 1 4 .Ａ 1 5.Ｂ 1 6.Ａ 1 7.Ａ、Ｄ 1 8.Ｂ 1 9.Ｃ 2 0… 相似文献
4.
1.name is Tom.am twelve.A.I1My B.I1IC.My1I D.My1My2.John is in.A.class3,grade1B.Grade1,Class3C.Class3Grade1D.Class3,Grade13.There is“f”in word“foot”.A.a1an B.an1theC.the1the D.an1/4.—my clockD—on the bed.A.Where is1ItsB.Where’s1It’sC.Where are1They’reD.Where1Its5.Tom needs my notebook.Can youit to himIA.take B.bring C.give D.read6.These sheep behind the house.A./B.are C.is D.be7.There are two windows the wall.A.on B.to C.in D.behind8.There are many books you and.… 相似文献
5.
《中学数学教学参考》2004,(11):53-56
一、选择题1 .2的倒数是 ( ) .A .-2 B .2 C .-12 D .122 .第五次全国人口普查结果显示 ,我国的总人口已达到 1 3 0 0 0 0 0 0 0 0人 ,用科学记数法表示这个数 ,正确的是 ( ) .A .1 .3× 1 0 8 B .1 .3× 1 0 9C .0 .1 3× 1 0 10 D .1 3× 1 0 93 .化简 (-x) 3(-x) 2 ,结果正确的是 ( ) .A .-x6 B .x6 C .x5 D .-x54.若x1,x2 是一元二次方程 2x2 -3x 1 =0的两个根 ,则x21 x22 的值是 ( ) .A .54 B .94 C .1 14 D .75 .图 1所示的电路的总电阻为 1 0Ω ,若R1=2R2 ,则R1,R2 … 相似文献
6.
《中学生物教学》2002,(Z2)
一、选择题 :本题包括 2 6小题 ,每题 2分 ,共 5 2分。1 .Ａ 2 .Ｃ 3.Ｃ 4 .Ｃ 5 .Ａ 6 .Ｃ 7.Ａ 8.Ｄ 9. Ａ1 0 .Ａ 1 1 .Ｃ 1 2 .Ｄ 1 3.Ｄ 1 4 .Ｃ 1 5 .Ｄ 1 6 .Ｄ 1 7.Ｄ 1 8.Ａ 1 9.Ｃ 2 0 .Ｄ 2 1 .Ｃ 2 2 .Ｄ 2 3.Ｄ 2 4 .Ｃ 2 5 .Ａ 2 6 .Ｄ二、选择题 :本大题包括 6个小题 ,每题 3分 ,共 1 8分。2 7.Ａ、Ｂ、Ｄ 2 8.Ａ、Ｂ 2 9.Ａ、Ｄ 30 .Ａ、Ｂ、Ｄ 31 .Ａ、Ｃ 32 .Ａ、Ｂ、Ｄ三、非选择题 :本大题包括 1 0个小题 ,共 80分。33 ( 8分 ) ( 1 )短 ( 2 )细胞周期受酶… 相似文献
7.
教学实践中 ,我发现学生初学小数除法时 ,由于不善于分配注意 ,或受整数除法的影响 ,练习或作业中常常出现以下错误情况 :一、把除数变成整数过程中常出现的问题1 .只把除数变成整数 ,被除数不变。例如 2 5 .5÷ 1 .7 1 .7丿 1 .52 5 .5 1 7 8 5 8 5 02 .不管被除数、除数的小数位数是否相同 ,都同时变成了整数。例如 ( 1 ) 4 .6 8÷ 1 .2 ( 2 ) 2 .0 7÷ 0 .1 1 5 1 .2丿 394 .6 8 36 1 0 8 1 0 8 0 .1 1 5丿 1 .82 .0 7 1 1 5 92 0 92 0 … 相似文献
8.
9.
1 选择题(1 )市售浓硫酸的质量分数为 98% ,其密度ρ=1 .84 g·mL-1 ,该硫酸的物质量浓度为 ( )。A .0 .1 84mol·L-1 B .1 .84mol·L-1C .1 8.4mol·L-1 D .1 84 .0mol·L-1 (2 )配置某药剂需用 0 .30 0mol·L-1 硫酸溶液 ,欲将2 0 0 0mL0 .1 0 0mol·L-1 硫酸溶液利用起来 ,需取3.0 0mol·L-1 硫酸溶液 ( )与其混合 ,才能配成0 .30 0mol·L-1 硫酸溶液。A .0 .1 4 8mLB .1 .4 8mLC .1 4 .8mLD .1 4 8mL (3)已知水的Kf=1 .86K·kg·mol·L-1 ,若将 2 .76 g甘油溶于 2 0 0g水中 ,测得凝固点下降 0 .2 79K ,则甘… 相似文献
10.
Ⅰ. 听力(20 分) A. 听对话, 选出与图画内容相符的选项。 ( 共 5 小题, 每小题 1 分) B. 听句子, 选择正确的答语。(共 5 小题, 每小题 1 分) 6. A. Certainly. Hold on, please. B. No, you can’t. C. It doesn’t matter. D. Great@ 7. A. Thank you. B. It doesn’t matter, but please be on time tomorrow. C. Sure. D. See you then. 8 9 1 C 1 1 1 1 1 D 1 1 1 1 28. A. Yes, it’s very hot. B. I don’t feel cold. C. I agree@ But it’ll be warmer later on. D. Don’t be cold. 9. A. Thank you. B. OK@ C. The same to you. D. Good@ 10. A. What bad weather@ B. I’m sure he’ll come. C. Oh... 相似文献
11.
钢液真空循环精炼过程的物理模拟 总被引：2，自引：0，他引：2
魏季和 《上海大学学报(英文版)》2003,7(1):1-17
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ａｓａｓｅｃｏｎｄａｒｙｓｔｅｅｌｍａｋｉｎｇｔｅｃｈｎｏｌｏｇｙ ,ｔｈｅＲＨ(Ｒｕｈｒｓｔａｈｌ Ｈｅｒａｅｕｓ)ｖａｃｕｕｍｃｉｒｃｕｌａｔｉｏｎｒｅｆｉｎｉｎｇｐｒｏ ｃｅｓｓｈａｓｂｅｅｎａｐｐｌｉｅｄｗｉｄｅｌｙａｎｄｄｅｖｅｌｏｐｅｄｒａｐｉｄｌｙｉｎｐｒｅｖｉｏｕｓｆｏｕｒｄｅｃａｄｅｓ .Ｗｉｔｈａｃｏｎｔｉｎｕｏｕｓｌｙｇｒｏｗｉｎｇｄｅｍａｎｄｆｏｒｈｉｇｈｑｕａｌｉｔｙａｎｄｈｉｇｈｌｙｃｌｅａｎｓｔｅｅｌ,ｉｔｈａｓｎｏｗｂｅｃｏｍｅ ,ｔｏａｃｏｎｓ… 相似文献
12.
RH和RH-KTB精炼过程中钢液流动和混合特性的研究 总被引：7，自引：0，他引：7
The flow and mixing characteristics of molten steel during the vacuum circulation refining,including RH(Ruhrstahl-Heraeus) and RH-KTB(Ruhrastahl-Heraeus-Kawasaki top blowing) processes,were investigated on a 1/5 linear scale water model of a 90t multifunction RH degasser,The circulation rate was directly and more accurately determined,using a new method by which the more reliable results can be obtained.The fluid flow pattern and flow field in the ladle were demonstrated,observed and analyzed.The mixing time of liquid in the ladle was measured using electrical conductivity method.The residence time distribution in the RH model was obtained by tracer response technique.The influence of the main technological and geometric factors,including the gas top blowing*(KTB) operation,was examined.The results indicated that the circulation rate of molten steel in the RH degasser can be fairly precisely calculated by the formula:Q1p=0.0333Qg^0.26Du^0.69Dd^0.80(t/min),where Qg-the lifting gas flow rate(NL/min);Du and Dd-the inner diameters of the up and down-snorkels(cm),respectively.The maximum value of circulation rate of molten steel in the case of the 30cm diameters either of the up-and down-snorkels for the RH degasser(the “Saturated” rate) is approximately 31 t/min.the corresponding gas flow rate is 900NL/min.Blowing gas into the vacuum chamber through the top lance like KTB operation does not markedly influence the circulatory flow and mixing charateristics of the RH process under the conditions of the present work.There exist a major loop and a large number of small vortices and eddies in the ladle during the RH refining process.A liquidliquid two-phase flow is formed between the descnding stream from the down-snorkel and the liquid around the stream.All of these flow situation and pattern will strongly influence and determine the mixing and mass transfer in the ladle during the refining.The correlation between the mixing time and the stirring energy density is τmε^0.50 for the RH degasser.The mixing time rapidly shortens with an increase in the lifting gas flowrate.At a same gas flow rate,the mixing times with the up-and down-snorkel diameters either of 6 and 7cm are essentially same.The 30cm diameters either of the up-and down-snorkels for the RH degasser would be reasonalble.The concentration-time curve showed that three circulation cycles are at least needed for complete mixing of the liquid steel in the RH degasser. 相似文献
13.
分析了转炉冶炼轴承钢的技术优势,以GCr15轴承钢为例,采用全铁水脱硫-复吹转炉吹炼-LF＋RH精炼-大截面连铸流程生产轴承钢工艺可行。采用优质铁水并预处理脱硫,有效地控制原料中〔P〕≤0.01%、〔S〕≤0.003%;通过复吹转炉吹炼,使钢中碳-氧反应趋于平衡,弥补了因低拉碳造成的钢中氧含量高的不足;利用LF及RH精炼,使钢材中的有害元素〔Ti〕≤30×10-6、〔O〕≤8×10-6、〔N〕≤38×10-6、〔H〕≤0.8×10-6;通过大截面连铸改善了大规格轴承钢低倍缺陷。 相似文献
14.
对X70石油管线钢的生产工艺技术进行试验研究,采用铁水脱硫（DS）一复吹转炉（BFC）一LF-IR钢包精炼一RH真空精炼一板坯连铸（CC）的生产工艺路线冶炼管线钢,钢材实物质量检测结果表明,钢中化学成分控制准确,夹杂物以球型为主,弥散分布;硫、磷、气体含量的控制均达到国际先进水平 相似文献
15.
The change and control of nitrogen content in molten steel was investigated through the production process of“LD-BAr-LF-RH-CC”. Results show that nitrogen content reduces gradually in converter-steelmaking stage, rises rapidly from the end of converter process to the end of argon station process, continues to increase in ladle furnace process, and decreases slightly in RH refining stage. Since nitrogen is removed mainly by BOF steelmaking and vacuum refining operations, nitrogen in molten steel should be removed as much as possible in these two operations. However, nitrogen uptake should be minimized in other operations of molten steel production process. 相似文献
16.
魏季和 《上海大学学报(英文版)》2002,6(1):1-23
The available studies in the literature on physical and mathematical modeling of the argon-oxygen decarburization(AOD) process of stainless ssteel have briefly been reviewed.The latest advances made by the author with his research group have been summarized.Water modeling was used to investigate the fluid flow and mixing characteristics in the bath of an 18t AOD vessel,as well as the “back-attack” action of gas jfets and its effects on the erosion and wear of the refractory lining,with sufficiently full kinematic similarity.The non-rotating and rotating gas jets blown through two annular tuyeres,respectively of straight-tube and spiral-flat tube type.Were employed in the experiments.The geometric similarity ratio between the model and its prototype(including the straighttube type tuyeres)was 1:3 ,The influences of the gas flow rate,the angle included between the two tuyeres and other operating parameters,and the suitability of the spiral tuyere as a practical application,were examined.These latest studies have clearly and successfully brought to light the fluid flow and mixing characteristics in the bath and the overall features of the back-attack phenomena of gas jfets during the blowing.nd have offered a better understanding of the refining process.Besides,mathematical modeling for the refining process of stainless steel was carried out and a new mathematical model of the process was proposed and developed.The model performs the rate calculations of the refining and the mass and heat balances of the system.Also,the effects of the operating factors,including adding the salg materials.crop ends,and scrap,and alloy agents;the non-isothermal conditions;the changes in the amounts of metal and slag materials,crop ends,and scrap,and alloy agents;the non-isothermal conditions;the changes in the amounts of metal and slag during the refining;and other factors were all considered.The model was used to deal with and analyze the austenitic stainless steel making (including ultra-low carbon steel) and was tested on data of 32 heats obtained in producing 304 grade steel in an 18t AOD vessel.The changes in the bath compostion and temperature during the refining process with time can be accurately predicted using this model.The model can provide some very useful information and a reliable basis for optimizing the process practice of the refining of stainless steel and control of the process in real-time and online. 相似文献
17.
在50Kg氧化镁坩埚真空感应炉上进行高硅电工钢的脱氧试验。结果表明,通过控制原料的成分、高真空下的碳氧反应和炉衬分解向钢液中的供氧,可使钢液的总氧含量≤15×10^-6;在维持高温高真空条件下,当钢液中的反应达到一定程度后,延长精炼时间并不能降低钢液的总氧含量;完成精炼后加入硅钙合金沉淀脱氧可进一步降低钢液的总合氧量,但脱氧效果有限。 相似文献
18.
利用六西格玛工具,通过对本钢矩形坯白点的成因分析,提出了采用控制入炉物料的干燥、对白点敏感性钢种采取RH真空处理、加强坯材保温等措施,可有效控制白点的产生。得出如果钢水〔H〕含量控制在5ppm以下可以基本保障钢材不出现白点缺陷。 相似文献
19.
王艳 《辽宁科技学院学报》2008,10(2):4-5
常见的与薄板坯连铸工艺相配合的精炼工艺有LF、RH和CAS。通过对三种精炼工艺的适用性分析,探讨了在生产热轧卷板时,利用提高精炼操作水平等措施可以实现LF与薄板坯连铸机的合理衔接;在生产冷轧薄板时,RH与CAS是与薄板坯连铸相匹配的较为合理的炉外精炼工艺。 相似文献
20.
通过对重轨钢中夹杂物的研究发现,在铸坯和钢轨中存在有一种类型的MnS复合夹杂,其外围有一层TiS或者Ti-Mn-S,能够在钢轨轧制过程中阻止MnS夹杂的变形。由此提出了加钛处理控制重轨钢中MnS夹杂的新思路,并对这种思路的可行性进行了分析探讨。当钢中氧含量很低,加入适量钛,控制在钢液中不析出钛氧化物,而在凝固过程中首先析出MnS,而后在MnS外围析出TiS或者Mn-S-Ti的复合夹杂物,可以抑制MnS夹杂在轧制过程中的变形。建议工业上冶炼重轨钢时,可以在RH精炼结束时加入0.01%~0.02%的钛,以达到控制长条状MnS夹杂的目的。 相似文献