《小学科技》2003年度1-12期总目次

篇名后的数字,连线前的为期连线后的为页数。科技奶酪回生的低温技术系中有没有其他外星人来客吗有外星人 1一16 2一16 3一12 4一18 5一8 6一20 7一14 8一12 9一1210一1211一2212一12材料实验室红外线遨游归来属也怕冷 1一2 2一2 2一4 3一2 3一4 4一2 4一4 5一26一16 7一2 8一2 9一210一211一212一2探索大自然鬃戮臀墉黔类起源于恐龙吗l一4次)娜)务一气比界恐饰地区的魔鬼杀手5一16宇宙的奥秘物的入侵宙是什么样的 QQ不倒问料也会发光吗大为什么不打雷夜为什么见不到银河睛难道不怕冷吗气中的“维生素”豚睡觉时会淹死吗子饿了为什么会“咕…     

科技书廊

新书目号书名定价‘(元)作老出版时间自办社522一256社526一099社326一100社325一025科291一097 1 15科266一116 1 17 103科289一104 105科275一118科252一128科252一129科252一130科284一117自办科255一372科261一099科289一108科288一131自办自办自办科293一107科287一069自办自办自办自办农011一041市场营销管理(上、下)(重版)科技应用文写作指南《火炬计划管理干部培训教材丛书》①高新技术企业经营管理②企业国际化概论管理者如何提高自身素质全球预替—1992年世界形势评述食品加工技术工艺和配方大全(上、中、下)(重版)食品加工技术工…     

铁钉、战马与王朝

在英国民间流传着这样一首歌谣：缺了一枚铁钉,掉了一只马掌;掉了一只马掌,失去一匹战马;失去一匹战马,损了一位骑兵;损了一位骑兵,丢了一次战斗;丢了一次战斗,输掉一场战役;输掉一场战役,毁了一个王朝。     

中山大学学报(自然科学版)卷期一览表

本刊从1955年创刊至今,从未分卷,且两次中断,为了便于检索,从1989年起,以1年为1卷,顺序编排卷号,在此以前均为虚拟卷号。落总期备注1 年19751976197719781979198019811982198319841985198619871988期总期备注1一41一41一41一41一41一41一41一4l一41一41一41一41一41一4新6一9新     

关于两个组合恒等式

入bcl值等式【’X一‘二+,+二)一艺(又)‘X、‘·)二一(、。一(,卜一‘)·。(1)Cauehy公式“J艺(又)‘X+“,““十”一‘’一艺(,,、‘二礴,一}一”’(2)(l)的证明:由文〔1〕知只须证明X一(一l一,十·,一乏(;)(X+介)一(,卜一‘)一(3)0‘圣‘。‘己‘3,的右边为“,,,则‘(;,一。里。(:)(·+,卜‘,一:‘,干左’设O镇l成n一1,则,了!)(,卜艺(、)!须又二{礴‘·+一‘,’、一’一““+‘,‘-_孟若n几~‘k艺(·)‘粉’‘厂‘退(·+一‘一“,一‘一“,+‘十‘”“’,孟尸n一乙故f‘,(一x一n)一(n)‘乏 O次夕,军n,乙(一l)、,(”于‘)‘·+·:‘一…     

部份品种市场参考价格

.春剑 皇梅35一45万元、玉海棠20一30万元、桃园三结义35一50万元、 五彩想麟20一30万元(卞)、冠蝶50000一60000元(宁)、五彩梅 40000一50000元、天府荷30000一40000元(个)、一品荷1 5000一 20000元、花蕊夫人20000一25000元、西蜀道光4500一6000元、隆昌 素600一800元、银杆素200一300元。 .春兰 天彭牡丹13一18万元(卞)、乌蒙牡丹60000一80000元(寸)、 锦绣中华40000一50000元(’)、冠神40000一50000元、红孩儿 10000一15000元(1)、中华麒麟10000一15000元(布)、荷瑞 20000一25000元、虎蕊25000一30000元(个)、大元宝25000一 30000元(卞)…     

不等式常用证法思路分析(续)

〔问题十〕试证:1 aZ一{一a4十…十a 21>吐1(。>0)2命题成立。,土.了一1占i一a一卜a3 a证明:当左式二」‘一卜·一卜aZn二l时,士_叮>2“-aa2(a>O),右式二设当”一无l付,原命题成立.1一卜aZ一于a4十…a一卜a3一{-·一{一aZ口2 一、即无 1 k令f(k)1一卜护十a月一卜…十a利a十a3一干-…十a三‘三一,则厂(k)>乙 1 k当n二花 1时1一卜耐 少一卜·一卜妒 a一}一a3十…十a名、一 1一aZa〔1一aZ 2)1)二 1〕.1一a产f乙十,a(1 aZ‘) 、‘了.七,尤.j(八·︺而f(k十1)十 1f(无) 1一aZ‘,2、一二厂—一犷不了-二卞a贬1一a:‘了‘’」a(1一aZ‘)1一az‘…     

143~#液体固化型感光不饱和聚酯的合成与应用

一、感光树脂的制备甲、配方原料名称分子t克分子比!重量比(克)盛nl口O甘OR一,二6C‘连一n︸8︸g﹃勺9‘.上d.几对苯二甲酸二甲脂 二缩叁乙二醇l~1。5醉锌酚顺酷对乙、化学反应第一步:酷交换反应。_____矛一飞___________________Zn(Ac)””(一‘’一)’-火~户一犷t,一七h’十2朋(七”’一确一。,3且-一-一Ho、cH:一cHZ一。)3胜一仁丫恶一。(cHZ一cHZ一。)3H·ZcH3oH对苯二甲酸双羚式缩叁乙二醇醋。 第二步:醉酸醋化反应。O一C一O(CH:一CH:一O)。工I0O ZHO((几HZCHZ一O),H O0矛叱\护‘决 CC 一一 C IC HH nOO一C一O(CH…     

苯基溴化镁溶液和苯甲酸的半微量制备法(格氏反应)

一、反应C 6H,Br Mg无水乙醚”C 6H,MgB:*‘ 尹C 6H。MgBr CO Zee~~)CoHS一C一O一MgBr OO 尹产 C 6H:一C一O一MgBr HCles一一知C。H:一C一OH MgBrCI OO 尹尹 C 6H。一C一OH NaOH一~>C。H,一C一ONa H20 O 岁 C 6H、一C一ONa HCI一一)C6H,COOH NaCI 本实验使用药品量少,仪器简单,操作方便,一般只需l一1.5小时即能完成。二、药品及仪器: 药品仪器 澳苯(无水)Zml锥形烧瓶looml一只 乙醚(无醇,无水)10ml回流冷凝器球型1只 镁屑0.5克干燥管一球l只 碘(晶体)1一2粒烧杯soomlZ个 乙醚烧杯loomlZ个 浓硫酸温度计100…     

1996年《科技潮》1～12期要目索引

潮声春天絮语面对时代拥抱生活品味人生开发生命智慧如金感悟时世迫寻崇高选择挑战营造明天(l一I)(2一l)(3一I)(4一l)(5一l)(6一l)(7一I)(8一l)(9一l)1(}一I)f书荣·庞其清杨奇逊·杨昆 热点透视神灯频谱风云记(L)Windows95劲风在中国登陆?(5一24)(8一18)仲大军(l一15)无形朋友     

Kac—Moody群的无限维代数子群

Ｓ．Ｐ．Ｗａｎｇ在文献中已经提出了Ｋａｃ－Ｍｏｏｄｙ群的有限维代数子群的概念。笔者首先把Ｃｈｅｖａｌｌｅｙ闭子群定理推广到Ｋａｃ－Ｍｏｏｄｙ群的有限维代数子群,即定理１．３。其次,通过子群和子代数之间的对应建立了Ｋａｃ－Ｍｏｏｄｙ群的无限维代数子群,并且证明无限维代数子群的说法是有限维代数子群的推广。     

关于Mn＊-半群

本文研究了全体n阶矩阵关于乘法和转置构成的＊-半群,给出了＊-子半群的概念证明了Mn存在＊-正则子半群、＊-逆子半群、＊-子群．证明了对于任意正整数n,如果一个集合S的元素个数为n^2＋1则可以定义乘法和＊运算把S变成正则＊-半群,而且S是一个逆半群．     

Relationship between lattice mismatch and ionic conduction of grain boundary in YSZ

The grain boundary plays an important role in the electrical behaviors of solid oxide electrolytes for solid state fuel cells. To reveal the relationship between the structure and the ionic conductivity of grain boundary,the conductive properties of {1 1 1} and {1 1 0} twist grain boundaries in 8 mol% yttria-stabilized zirconia have been examined. These boundaries have a series of Σ values defined by the coincident site lattice model. It has been found that the activation energy of {1 1 1} twist grain boundary increases and then decreases with the Σ value,while that of the {1 1 0} boundary shows an opposite trend. It is suggested that the properties can reflect the balance of the effects of lattice mismatch on the diffusion ability of oxygen vacancies and the segregation of oxygen vacancies and Y3 tions. Therefore,the properties in polycrystalline electrolyte can be adjusted by controlling the grain boundary structures.     

Novel flexible broadband microwave absorptive fabrics coated with graphite nanosheets/polyurethane nanocomposites

Graphite nanosheets (GNS) were prepared by surfactant assisted ultrasonication from expanded graphite (EG) and followed by coating onto vinylon fabrics with water-borne polyurethane (WPU). The morphology of GNS and GNS/polyurethane (PU) coatings was characterized by field emission scanning electron microscope (FESEM), and the structure of GNS was studied by fourier transform infrared (FTIR) spectroscopy. Electromagnetic (EM) parameters indicated that GNS is a kind of dielectric loss material, in which little magnetic loss is found. Reflection loss (RL) results showed that both GNS content and coated thickness had great influences on the microwave absorption. For the fabric coated with GNS/PU nanocomposites (30/100 by weight, wet thickness of 0.39 mm for dry areal density in 130 g/m2), RL values exceeding 5 dB could be obtained in the frequency range of 10.7–18 GHz, while 10 dB in 12.7–18 GHz, and a minimum value of 28 dB at 15.2 GHz. These GNS/PU coated fabrics are light and flexible with much thin and low-cost coated layer, and showed great potential in radar camouflaging and electromagnetic interference application.     

A facile and green preparation of durian shell-derived carbon electrodes for electrochemical double-layer capacitors

A facile and green preparation of high surface area activated carbons with mixed microporosity and mesoporosity from durian shell waste is reported in this work. The pore structure and surface chemistry of the parent carbon were modified by the combination of ultrasonication and microwave irradiation techniques. The effects of temperature and time in the ultrasonication treatment and power output and time in the microwave irradiation were studied. The electrochemical performance of carbon electrodes for supercapacitors was tested by cyclic voltammeter (CV) and galvanostatic charge–discharge. The results show that the capacitive energy storage of electrodes is critically dependent on the microporosity and surface chemistry of activated carbons. The highest electrode capacitance in this work was 103.6 F/g that prepared from activated carbon modified at an ultrasonication temperature of 323.15 K for 10 min and microwave power output of 900 W for 10 min.     

Effect of La0.8Sr0.2Co0.2Fe0.8O3-δ morphology on the performance of composite cathodes

In the present work,one dimensional La0.8Sr0.2Co0.2Fe0.8O3 δ(LSCF) nanofibers with the mean diameter of about 100 nm prepared by electrospinning were deposited on Gd0.2Ce0.8O1.9(GDC) electrolyte followed by sintering to form one dimensional LSCF nanofiber cathode. And LSCF/GDC composite cathodes were formed by introducing GDC phases into LSCF nanofiber scaffold using infiltration method. The polarization resistances for the composite cathode with an optimal LSCF/GDC mass ratio of 1/0.56 are 0.27,0.14 and 0.07 Ω cm2at 650,700 and750 1C,respectively,which are obviously smaller than 2.26,0.78 and 0.29 Ω cm2of pure LSCF nanofiber cathode. And the activation energy is1.194 eV,which is much lower than that of pure LSCF nanofiber cathode(1.684 eV). These results demonstrate that the infiltration of GDC into LSCF nanofiber scaffold is an effective approach to achieve high performance cathode for solid oxide fuel cells(SOFCs). In addition,the performance of composite cathode in this work was also compared with that of our previous nanorod structured LSCF/GDC composite cathode.     

Experimental and numerical analyses of pure copper during ECFE process as a novel severe plastic deformation method

In this paper,a new severe plastic deformation method called equal channel forward extrusion(ECFE) process has been proposed and investigated by experimental and numerical approaches on the commercial pure copper billets. The experimental results indicated that the magnitudes of yield strength,ultimate tensile strength and Vickers micro-hardness have been markedly improved from 114 MPa,204 MPa and68 HV as the annealed condition to 269 MPa,285 MPa and 126 HV after the fourth pass of ECFE process,respectively. In addition,scanning electron microscopy observation of the samples showed that the average grain size of the as-received state which is about 22 μm has been reduced to 1.4 μm after the final pass. The numerical investigation suggested that although one pass ECFE process fabricates material with the mean effective strain magnitude of about 1,the level of imposed effective plastic strain gradually diminishes from the circumference to the center of the deformed billet.     

硝酸铕与氮杂冠醚配合物的伏安行为

用循环伏安法研究了硝酸铕与氮杂冠醚配合物在不同质子惰性溶剂中的电化学行为结果表明，溶剂介质和冠醚的结构对铕与冠醚配合物的氧化还原反应有显著影响     

The precipitation strengthening behavior of Cu-rich phase in Nb contained advanced Fe–Cr–Ni type austenitic heat resistant steel for USC power plant application

Copper has been used as a strengthening element in newly developed Fe–Cr–Ni type austenitic heat resistant steel for inducing Cu-rich phase precipitation to meet high temperature strength requirement for 60°C Ultra Super-Critical (USC) coal fired power plants for many years. However, the precipitation behavior and strengthening mechanism of Cu-rich phase in these advanced austenitic heat resistant steels is still unclear. In order to understand the precipitation strengthening behavior of Cu-rich phase and to promote high strength austenitic heat resistant steel development, 18Cr9 NiCuNb steel which is a Cu-added Nb contained advanced Fe–Cr–Ni type austenitic heat resistant steel has been selected for this study to be aged at 650°C till to 10,000 h. Micro-hardness and room temperature tensile test were conducted after long-time aging. SEM,TEM, HRTEM and three dimensional atom probe (3DAP) technology accompanying with thermodynamic calculation have been used to investigate the Cu-rich phase precipitation behavior during 650°C aging. The experimental results showed that Cu atoms can quickly concentrate in clusters at very early precipitation stage to form the fine nano-size Cu-rich ‘‘segregation areas’within less than 1 h at 650°C. With increasing aging time at 650°C Cu atoms continuously concentrate to Cu-rich segregation areas (clusters) and simultaneously other kinds of atoms such as Fe, Cr and Ni diffuse away from Cu-rich segregation areas to austenitic matrix, and finally to complete the transformation from Cu-rich segregation areas to Cu-rich phase. However, there is only Cu atoms concentration but not crystallographic transformation from early stage of Cu-rich clusters forming to the final Cu-rich phase formation. Even the Cu atom becomes the main composed element after 500 h aging at 650°C the Cu-rich phase still keeps coherent relationship with austenitic matrix. According the experimental results in this study, Cu-rich phase precipitation sequence which starts from the Cu atom segregation followed by the Cu diffusing from matrix to segregation areas and Fe, Cr and Ni atoms diffuse out from Cu-rich areas to matrix without crystallographic transformation is proposed. The Cu-rich phase is the most dispersed phase and contributes the most important strengthening effect among all precipitated phases (M23C6, MX and Cu-rich phase). It has been found that Cu-rich phase is very stable and still keeps in nano-size even for 10,000 h aging at 650°C. The unique precipitation strengthening of Cu-rich phase in combination with nano-size Nb-rich MX phase and grain-boundary M23C6carbide contributes excellent strengthening effect to 18Cr9 NiCuNb austenitic heat resistant steel.     

Effect of pickling processes on the microstructure and properties of electroless Ni–P coating on Mg–7.5Li–2Zn–1Y alloy

The electroless plating Ni–P is prepared on the surface of Mg–7.5Li–2Zn–1Y alloys with different pickling processes.The microstructure and properties of Ni–P coating are investigated.The results show that the Ni–P coatings deposited using the different pickling processes have a different high phosphorus content amorphous Ni–P solid solution structure,and the Ni–P coatings exhibit higher hardness.There is higher phosphorus content of Ni–P amorphous coating using 125 g/L Cr O3and 110 ml/L HNO3(w68%)than using 180 g/L Cr O3and 1 g/L KF during pre-treatment,and the coating structure is more compact,and the Ni–P coatings exhibit more excellent adhesion with substrate(Fcup to22 N).The corrosion potential of Ni–P coating is improved and exhibits good corrosion resistance.As a result,Mg-7.5Li-2Zn-1Y alloy is remarkably protected by the Ni–P coating.