高中数学新教材一道习题解答的评析——兼与文[3]、文[4]、文[5]作者商榷

苏教版必修4(文[1])中习题:如图1所示,一根绳穿过两个定滑轮,且两端分别有3N、2N的重物.现在两个滑轮之间的绳上挂一个重量为m(N)的重物,恰好使得系统处于平衡状态,求正数m的取值范围.这是一道内涵丰富的数理结合题.文[2]、文[3]、文[4]给出了答案不同的两种解法,文[5]对学生的一个错解作了辨析,但其基本观点值得商榷.我的学生在作业中出现了如下6种解法,值得品味,     

Design and Synthesis of 4,4'-Disubstituted-[2,2']-Bipyridines for Catalyzing CO/Styrene Copolymerization with Palladium(Ⅱ)

A series of 4,4'-disubstituted-[2,2']-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been synthesized and employed in the copolymerization of carbon monoxide(CO)and styrene. The available bipyridine and its derivatives were coordinated with palladium(Ⅱ)acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of 13 C NMR, FTIR, differential scanning calorimetry(DSC)and element analysis techniques concerning its structure and thermal performance. The effect of different electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of copolymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composition, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2'-bipyridine ligand(1 356 g STCO/(g Pd · h)), when the molecular weight and polydispersity index of the polyketone are M n=8 502,M w=1 3440 and M w/M n=1.581, respectively.     

[德]N·佩塞施基安心理学思想述评

[德]N·佩塞施基安积极心理治疗主要内容 [德]N·佩塞施基安是积极心理治疗学派代表人物,他的积极心理治疗理念以跨文化为基础,以冲突为中心,运用故事作为治疗者与病人之间媒介,启发患者运用直觉和想像,在不与病人的观念直接发生冲突的情况下,由心理治疗师引导用通俗易懂助人的语言,而不是用许多艰深的科学术语,使病人最终放弃自己的片面看法,以达到治疗的目的.     

N[1,2,3,…]在N4[14,24,34,…]中的表达式

研究N的元素表示为N4中元素的代数和的最简表达式的项数问题,并提出合理的猜想.     

Stress and Fracture Strength Analysis for Three-Way Pipes

l lgtroductionIt is well known that the safety of pipeline systemsfor transpofting oil or gas is very important in the oil orgas industry, and it will be a catastTophe if an accidentoccurs. Howevef, there are a lot of methods for ensuringthe safety of such pipeline systems, for instance,TopRAM program['] (TransCanada Pipeline RiskAssessment Model), IAP program['] (The integrityAssessment Program), In-line inspection tools for crackdetection in gas and liquid pipeline['l etc. The safety …     

在室温和常压下用机械合金化方法制备Fe5C2金属间化合物

Single phase Fe5C2 intermetallic compound was prepared by mechanical alloying method. The phase and crystal structure of sample were analyzed with X-ray differaction spectrum. The decomposing temperature of the Fe5C2 compound is 596.4℃ determined by the DSC curve. It is further shown that the size of nanometer crystal grain is an important condition for carrying out the solid state reaction at room temperature and normal pressure.     

Synthesis, Crystal Structure and Nonlinear Optical Properties of a Novel Imidazole DerivatiVe

A new compound 1-[trans-4-((N-ethylcarbazolyl) vinyl) phenyl]imidazole(C25H22N3,Mr=364.46)has been synthesized,and its crystal structure was determined by single-crystal X-ray diffraction method.The crystal is of monoclinic,space group P21/c with a=9.298(2) A,b=8.648(2) A,c=25.394(7) A,β=110.46(3)°,V=1912.9(8) A3,Z=4,Dc=1.266g/cm3,μ=0.075mm-1,F(000)=772,The structure was refined to R=0.0685 and wR=0.1612 for 3570 unique reflections with Rint=0.0645.The structural determination shows that the molecular structure is a perfectly planar π-conjugated system,and there is a high electronic delocalization in the molecule.The compound shows photoluminescence with a maximum emission at 439nm and a shoulder emission at 458nm upon the maximum-excitation wavelength at 264nm.     

一种新的配位聚合物{Me6[14]N4Co[Cd（SCN）4]}的水热合成和表征

以水热法合成了一个新的希夫碱大环配位聚合配合物M e6[14]N4Co[Cd（SCN）4]（M e6[14]N4=5,7,7,12,14,14,1—六甲基—1,4,8,11—四氮杂环十四—4,11—二烯）,并用红外光谱和元素分析的手段对其进行了表征.     

奉节方言中的[x]与[f]

一般人们认为奉节方言中只有[x]声母,而没有[f]声母.作为土生土长的奉节人,我认为是有的.去年寒假(2003.1-2003.2)我特意就此问题作了一次调查,结果证明奉节话中确实是有[f]声母的字,并且,在普通话中读[x]声母的字,在奉节话中有些却读[f]声母,相反,在普通话中读[f]声母的字,有的却读成了[x]声母.即是说,[x]、[f]两声母在奉节话中是相混的.     

The Labiodentalization of [ts], [ts‘], [s] in Ningyang Dialect

This paper aims to analyze the Labiodentalization of the retroflexes[ts],[ts‘],[s]in Ningyang dialect.From the general knowledge of phonology,this paper will firstly focus on the introduction of Ningyang dialect and the articulation of these three sounds.Then,with the results from the field work,the labiodentalization of[ts],[ts‘],[s]is explained from two aspects,one is the assimilation of the vowel[u],the other is the hierarchical change of phonology.This study concludes with the reason of the labiodentalized process of[ts],[ts‘],[s]in Ningyang dialect over time,and points out a further trend of this kind of phonological change.     

Chaotic Motions of Nonlinear Viscoelastic Beams

l introductionThe Galerkin trUncation is widely used to stody thedynandcal behavior (especially the nonlinear dynamicalbehavior) of,trU.tUre,[i]. The Galerkin method is alsoaPPlied to stUdy dynamical behavior of viscoelashcbeams. Suire and Cederbaum [2] analyzed periodic andchaohc behavior of viscoelastic beams with the Idledeflection, and the constitUtive relation in their work isthe BoltZmann superposition Principle. Argyris[']myes-tigated chaohc motion of viscoelastic beamsbased on a …     

[新干线读者评选最受欢迎]动漫人物排行榜

5犬夜叉位[犬夜叉]6.冲田总司[新撰组异闻录]7.奇牙[猎人]7.爱德华·艾尔利克[钢之炼金术士]9.该隐[毒伯爵该隐]10.酷拉皮卡[猎人]11.李小狼[魔卡少女樱]12.绯村剑心[浪客剑心]13.江户川柯南[名侦探柯南]14.八戒[最游记]15.玄奘三藏[最游记]16.洛基[魔侦探洛基]17丹羽大助[天使怪盗]18.越前龙马[网球王子]19.路飞[ONE PIECE]20.皇昴流[东京巴比伦]     

Grafting Copolymerization of Styrene and Acrylic Acid onto Pre-irradiated Polypropylene Fabric

l introductionGrafting polytnerization is a valuable method forthe modification of the chemical and physicalProperties of polymer surfaces. It can provide somedesirable Properties such as biocompatibility['],.ion-exchWe['] and thermo-sensitivity['], etc. somemethods have been studied in grafting polymerizstion,for example, ionization irradiation['], ultravioletlight['], plasma, chemical initiators and others[6].Radiation grafting is one of the most Promisingmethods because it can be effective…     

P无穷大实数 N[P]的连续性

本文试图证明│R[P]对极限运算的完备性,并给出单调有界性定理,从而为建立│R[P]上的微积分打下基础。     

新型杂多酸（C5N2H6）3（C5N2H7）3[（PO4）Mo12O36]·2H2O的水热合成与晶体结构

合成了一种未见报道的标题化合物（（C5N2H6）3（C5N2H7）3[（PO4）Mo12O36]·2H2O,Mr=2403.00）并得到单晶,晶体衍射实验发现其属于单斜晶系,P2（1）/n空间群,晶体学参数：a=13.316（3）,b=22.414（5）,c=20.063（4）,α=90.00（4）°,β=100.743（3）°,γ=90.00°,V=5883（2）3,Z=4,Dc=2.713Mg/m3,μ（MoKα）=2.608mm-1,F000=4604,最终R=0.0596,wR=0.1345,GoF=1.042.配体由由簇阴离子[（PO4）Mo12O36]3-之间通过端基氧与2-氨基吡啶形成氢键而相互连接,中间填充了一些水分子及2-氨基吡啶.     

Jennifer Lopez

Real Name: Jennifer LopezD.O.B:July 24,1970Place of Birth:Bronx, N.Y.,USAHeight: 5'6"Husband:Cris JuddEx-Husband:Ojani NoaWhy is she famous?She is considered by the media and public alike as one of the most beautiful(and sexiest)women in the world. She has 2 multiplatinum albums to her credit On the 6 and J-Lo. She has starred in hit movies The Cell, The Wedding Planner and Out of Sight.     

二水合-[N,N'-双(2-苯胺基)乙二酰胺]合镍(II)的合成与表征

合成了新型二元配合物二水合-[N,N'-双(2-苯胺基)乙二酰胺]合镍(II),并用元素分析、红外、紫外、核磁共振等进行了表征,通过对其荧光性能的研究,发现Ni2 对配体二水合-[N,N'-双(2-苯胺基)乙二酰胺有较强的荧光猝灭作用.     

[x]与{x}

我们知道,[x]表示不大于x的最大整数,{x}表示x与[x]的差。本文介绍它们的一些基本性质及其简单应用。由[x]及{x}的意义容易知道: 1.[x]+{x}=x. 2.[{x}]={[x]}=0. 3.[x]≤x<[x]+1. 4.若x≥y,则[x]≥[y].特别若x≥0,则[x]≥0。 5.若     

Yield and quality responses of citrus （Citrus reticulate） and tea （Podocarpusfleuryi Hickel.） to compound fertilizers

Experiments were carried out with citrus （Citrus reticulate） and tea （Podocarpus fleuryi Hickel.） to study the effects of compound fertilizers on their yields and quality. In the citrus experiment, application of compound fertilizers increased available P K and Mg contents in soil but decreased alkali-hydrolyzable N contents in soil and N, P and K contents in leaves. In the tea experiment, application of compound fertilizers increased available P, K and Mg contents in soil and N, P, K and Mg contents in leaves but decreased alkali-hydrolyzable N in soil compared with the urea treatment. Application of compound fertilizers could improve the quality of citrus and tea, increase their yields and enhance their economical profits significantly. Compared with the control, application of compound fertilizers increased citrus yields by 6.31, 12.94 and 17.69 t/ha, and those of tea by 0.51,0.86 and 1.30 t/ha, respectively. Correspondingly, profits were increased by 21.4% to 61.1% for citrus and by 10.0% to 15.7% for tea. Optimal rates of compound fertilizers were recommended for both crops.     

Synthesis of Protected Tetrapeptide, N-o-Ns-N （Me） - Val-N （Me） -Val-N （ Me ） -Val-N （Me） -Phe-O^tBu

The protected tetrapeptide, N-o-Ns-N （ Me ） -Val-N （ Me ） -Val-N （ Me ） -Val- N （ Me ） -Phe- OtBu, was prepared from L-valine and L-phenylalanine. Ted-butyl acetate and HClO4 were used to protect carbonyl group, o-nitrobenzenesulfonyl chloride and triethyl amine were used to protect amino group, and N-alkylation was finished with iodomethane. Then the protected amino acid was turned into acid chloride which was taken as coupling reagent. After 14 steps, such as protection, alkylation, deprotection and coupling, the protected tetrapeptide was obtained with a yield of 26.9%. The structures of intermediates and target compound were identified with NMR spectra and high resolution mass spectra.