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《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
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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
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《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
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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
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《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
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《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
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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
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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
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Two types of molecular and polymer devices employing (2-(4′-biphenyl)-5-(4““““““““-tert-butylphenyl)-1,3,4-oxadiazole) (PBD)and poly(N-vinylcarbazole) (PVK) as electron transport and hole transport materials, respectively, have been fabricated. The structures of these two devices are ITO/PVK( 70 nm)/PBD(60 nm)/A1 and ITO/PVK: PBD (1:1 by mass, 70 nm)/A1. The formation of exciplex is evident by comparing the electroluminescence (EL) of a bi-layer device and the photoluminescence (PL) of a PVK and PBD mixed film.The maximum emission energy of exciplex evaluated is consistent with the peak emission of EL. Blue emissions from both devices are obtained. The type of exicplex is interpreted based on the energy level diagram of the bi-layer device. 相似文献
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1 Introduction Organiclight emittingdiodes(OLEDs)haveattract edconsiderableattentionduetoitsgreatpotentialinefficiency ,low voltage ,large area ,lightweight ,andfull colorflat paneldisplays[1,2 ] .Forfull colordis plays ,itisnecessarytohaveefficientred ,green ,andblueemitterswithappropriatechromaticity .Bycom parisonwiththehighperformanceofblueandgreenOLEDs ,theperformanceandpurechromaticityofredOLEDsarestillrelativelypoor .UsuallyredOLEDsareimprovedbydopingreddyesintohostmaterialswit… 相似文献
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研究了以（PPQ）2Ir（acac）为客体,分别以PFO、PVK、PFB和PFG四种不同聚合物为主体掺杂体系的光谱性质.各种材料的紫外-可见吸收光谱和光致发光光谱的性质表明PVK和PFO与客体之间可以发生有效的能量转移.此外,与光致发光谱不同,发光器件电致发光光谱有较纯的红光发射,表明除了能量转移之外,电荷捕获也是实现器件红色发光的主要原因之一. 相似文献
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Emission characteristics of top emitting organic light-emitting devices (TOLEDs) with Ag as reflective anode, Al/Ag as semitransparent
cathode and 90–160 nm [N-(1-naphthy1)-N-pheny1-amino] bipheny1/tris-(8-hydroxy quinoline) aluminum (NPB/Alq3) sandwiched in the electrodes are examined. The electroluminescence (EL) spectra of the TOLEDs are simulated based on the
Fabry-Perot cavity theory. And the resonant modes in cavity structure of TOLEDs is discussed and clarified which can accurately
describe the work principle of the devices. A fairly good match between calculated values and experimental data is achieved
at different emission colors from bluish green to orange. 相似文献
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In order to compare two kinds of blue electroluminescent materials,we have investigated two kinds of blue OLEDs with the similar structure ITO/CuPc/NPB/JBEM:perylene/Alq/Mg:Ag[device(J)] and ITO/CuPc/NPB/DPVBi:perylene/Alq/Mg:Ag[device(D)].The difference of luminance and efficiency was not obvious for the two devices,However,there was remarkable difference for their lifetime.The device(J) achieved longer half lifetime of 1035h at initial luminance of 100 cd/m^2,and that of device(D) was only255h,According to their energy level diagrams,the differentce of their stability may originate from different host materials in the two devices.It may be attributed to the better thermal stability of JBEM molecues than that of DPVBi.It is shown that JBEM may be a promising blue organic electroluminescent material with great stability. 相似文献
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近年来,钙钛矿型有机金属卤化物材料受到了国内外研究人员的广泛关注,掀起了研究热潮。钙钛矿型有机金属卤化物材料具有高的光吸收系数、高的载流子迁移率、带隙可调、发光效率高等优异的性能,其独特的光致发光特性和电致发光特性使得其除了应用在光伏领域外,在光电探测器、发光二极管、激光器件等方面也有广阔的应用前景。文章针对纳米结构钙钛矿型材料的制备进行了介绍,对钙钛矿型有机卤化物材料的应用及研究进展进行了详细的阐述,本研究对解决能源危机以及治理环境污染具有一定的指导意义。 相似文献
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Three types of blue-violet light-emitting devices based on an exciton-confined structure have been prepared, in which different materials were used as emitting layers and hole-transporting layers. They had structures of ITO/CuPc/NPB/CPB/TPBi/Alq3/LiF/Al(DNC), ITO/CuPc/JO3/CBP/TPBi/Alq3/LiF/Al(DJC ) and ITO/CuPc/JO3/FNPD/TPBi/Alq3/LiF/Al(DJF). Here copper phthalocyanine (CuPc) acted as hole-injecting layer( HIL), N, N-bis-(1-naphthyl)-N, N-diphenyl-1. lbiphenyl-4-4-diamine(NPB) and J03 bole-transporting layers ( HTLs), 4,4‘-dicarbazolyl-1,1‘ -biphenyl (CBP) and FNPD as emitting layers( EMLs), N, arylbenzimidazoles (TPBi) as holeblocking layer ( HBL ), and tris(8-quinolinolato ) aluminium complex ( Alq3 ) as electron- transporting layer ( ETL). TPBi applied here is a good confinement to both charges and excitons, which make the devices emit blue-violet light originating from the emitter, CBP and FNPD. Their characteristics have also been investigated. The result shows that the device DNC based on NPB/CBP has the best performance among the three devices. The excellence of DNC is attributed to the better hole-transporting ability of NPB as compared with J03, and the better emitting ability of CBP as compared with FNPD, although the best matching of energy levels is found in the hole-transporting layer and emitting layer of the device DJP. 相似文献
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A kind of pyrazoline derivative 1,3-bis(phenyl)-5-(2-phenanthrene)-2-pyrazoline(TPp) was synthesized in order to obtain stable
film and applied to organic electroluminecsent diode as hole transporting material. Two devices with structures as indium-tin-oxide(ITO)
TPP (50 nm)/tris-(8-hydroxyquinoline) aluminum(Alq3) (50 nm)/Al (150 nm) and ITO /TPP (50 nm)/lithium
tera-(8-hydroxy-uinolinato)boron(LiBq4 (50 nm)/Alq3 (5 nm)/Al (150 nm) were fabricated, they showed good electroluminescent(EL)
performance and TPP was proved to be a good hole transporting material. 相似文献