查询词典 2-butene

A one-step method for the synthesis of aromatic indolizine derivatives byintramolecular 1,5-dipolar cyclization reaction of 2-(2-arylethenyl)pyridinium N-ylidesin the presence of an oxidant has been studied for the first time. In the presence ofelectron-deficient olefins, however, 2-(2-phenylethenyl)pyridinium N-ylides underwent1,3-dipolar cycloadditions and then aromatized in situ by TPCD to produce indolizinederivatives, indicating 1,3-dipolar cycloaddition proceed more readily than 1 ,5-dipolarcyclization in these conditions. Pyridinium disubstituted N-ylides, readily obtainedfrom corresponding pridinium and β-chlorovinyl ketone, underwent thermalintramolecular 1,5-dipolar cyclization to give indolizine derivatives easily.Indolizinecarbaldehyde derivatives were synthesized starting from 2-pyridinecarbaldehyde in four-steps involving 1,3-dipolar cycloaddition reaction.

本文首次研究了2-(2-芳基乙烯基)吡啶N-叶立德在氧化剂存在下的分子内1，5-偶极环化反应，采用一锅法合成了中氮茚衍生物；研究了这些N-叶立德的1，5-偶极环化和1，3-偶极环加成反应的选择性，发现当有缺电子烯烃存在时，优先进行1，3-偶极环加成反应，而不再发生分子内1，5-偶极环化反应；由β-氯乙烯酮方便地得到了烯丙基N-叶立德，他们在加热时进行分子内1，5-偶极环化反应而得到中氮茚衍生物；由2-吡啶甲醛为起始原料，通过1，3-偶极环加成反应等四步反应，得到了重要的中氮茚甲醛衍生物，这些反应都具有条件温和和操作简便的特点，是合成中氮茚衍生物的新方法。

A preparation method of the visible-light photocatalyst Bi2WO6 nano-powder is characterized by comprising the steps as follows:(1) the selection of raw materials;(2) bismuth nitrate Bi(NO33 question mark 5H2O is added into a citric acid solution to obtain the citric acid solution containing white sediment;(3) EDTA is added into ammonia water which is then added dropwise with the citric acid solution containing the Bi(NO3)3 question mark 5H2O so to obtain a solution of bismuth;(4) the solution of bismuth is added with (NH4)6W7O24 question mark 6H2O solution to form a precursor solution which is then stirred, dried, coked, cooled and ground to obtain decarburized powder;(5) the decarburized powder is roasted for 2h to 4h under 450 DEG C to 550 DEG C to obtain the visible-light photocatalyst Bi2WO6 nano-powder.

可见光催化剂Bi 2 WO 6 纳米粉体的制备方法，其特征在于它包括如下步骤：1原料的选取；2将Bi(NO 3 ) 3 5H 2 O加到柠檬酸溶液中，得到含有白色沉淀的柠檬酸溶液；3将乙二胺四乙酸加到氨水中，并缓慢滴加入含有Bi(NO 3 ) 3 5H 2 O的柠檬酸溶液中，得铋的溶液；4将(NH 4 ) 6 W 7 O 24 6H 2 O溶液加入上述铋的溶液中，组成前驱液；搅拌，干燥，焦化，冷却后，研磨，得去碳的粉体；5将去碳的粉体在450～550℃下焙烧2～4h后，得到可见光催化剂Bi 2 WO 6 纳米粉体。

The ordering degree of martensite is characterized by the spacingdifference,Δd, of some pairs of diffracting planes, the indices of which satisfy theequation (h_1~2-h_2~2)/3=(k_2~2-k_1~2)/n.

有序化程度用一些特定马氏体线对的面间距差值△d来表征，线对指数应满足下式：(h_1~2-h_2~2)/3=(k_2~2-k_1~2)/n(对9R马氏体n=1，对18R马氏体N=4)。

Panicle dense, narrowly oblong in outline, 10–22 cm; branches 2–5 cm, branchlets many, short, pilose in axils; racemes 2–4-noded with 7–11 spikelets, disarticulating at maturity, one spikelet of a pair sessile, the other pedicellate; internodes and pedicels 2–2.5 mm, slender with expanded tips, densely ciliate.

紧密的圆锥花序，轮廓的狭长圆形，10-22厘米；分枝2-5厘米，小枝很多，短，具柔毛的在腋处；总状花序2-4有节具7-11小穗，成熟时脱节，一对无梗，其它有花梗一小穗；节间和花梗2-2.5毫米，用被扩大的信息微薄，浓密纤毛。

Thirty-two patients (M 14, F 18 , age 32 a ±s 8 a) in smectite group were sprayed 0.1-0.2 g of smectite on the ulcer surface, qid for 4 d; 34 patients (M 16, F 18, age 32 a±9 a) in chlorhe x idine group gargled with 2% of chlorhexidine solution, qid for 4 d; 36 patients (M 16, F 20, age 32 a±11 a ) in chlorhexidine plus smectite group gargled firs t with 2% of chlorhexidine solution, and then were sprayed 0.1-0.2 g of smectite.

蒙脱石组32例(男性14例，女性18例，年龄32 a±s 10 a)，喷蒙脱石0.1～0.2 g于溃疡处，每日4次；氯己定组34例(男性16例，女性18例，年龄32 a±9 a)，用2%氯己定液漱口，每日4次；蒙脱石加氯己定组36例(男性16例，女性20例，年龄32 a±11 a)，先用2%氯己定液漱口，然后再喷蒙脱石0.1～0.2 g，每日4 次。3组疗程均为4 d。

Clinical Study on treatment of prostatic carcinoma high Intensity hocused ultrasound combined with hormone in the;2. To evaluate the roles and mechanism of IGF-2 on fetal growth and development during late gestation, pregnant ewes and rats were employed to investigate relationship between IGF-2 and metabolites, hormones of pregnant animals and their fetuses.

本文以绵羊、大鼠为实验对象，观测围产期妊娠母羊、胎儿和新生儿血浆IGF-2水平的动态变化及其与其它内分泌激素和代谢物水平之间的相关性，并研究了给予外源性IGF-2片段、葡萄糖、胰岛素和皮质醇对血浆IGF-2、胰岛素和代谢物水平影响，综合分析IGF-2在动物胚胎、新生儿生长发育中的作用，着重探讨IGF-2与营养代谢和内分泌之间的关系以及分泌的调节因素。

This is how it works: 2 huskies in front, 2 in the middle, 2 at the back, 2 humans at the sleigh.

雪橇这麽拉：2只哈士奇在前面，2只在中间，2只在后面，雪橇上坐2个人。

The crystal structures have been determined by X-ray diffraction method, which show that the new complex [Co2-Co(2)(0H2)s] belongs to the bridging binuclear complex and the system of monoclinic with space group P211~,unit cell parameters a8.3850(10)A, b=27.386(4) A, c=9.610(2) A,~=98.280(10)~,V=2 183.8(6) A3 , Z=4, Dc=l.746Mg/m3,~i =l.597mm, F(000)=1168, Final R=O.0253 and wR=O.0610 S1.009 ,The two Co2~ are in distorted octahedrons. The part of [2Co] possess an approximate D2d symmetry, while the part of [OCo(2)(0H2)5] has an approximate C2 symmetry.

结构分析表明配合物(1)[Co1，(DPC2-Co(2)(OH2)5]是一个未见报导的桥联双核配合物，属单斜晶系，空间群为P2_1／c，晶胞参数：a=8.3850(10)A，b=27.386(4)A，c=9.610(2)A，β=98.280(10)A，V=2183.8(6)A~3，Dc=1.746Mg／m3，Z=4，μ=1.597mm-1，F(000)=1168，结构偏离因子R=0.0253和ωR=0.0610，吻合因子S=1.009，Co_(1)和Co_(2)的配位多面体皆为扭曲正八面体，[_2Co_(1)]部分具有近似D_(2d)对称性，[OCo(2)(OH_2)5]部分具有近似C_2对称性。

PL spectra indicate that the emission bands at 515 and 542 nm correspond to the 2H(subscript 11/2)→4I(subscript 15/2) and 4S(subscript 3/2)→4I(subscript 15/2) transitions of Er(superscript 3+), respectively. In the samples, the cerium dopant exists as Ce(superscript 3+) and Ce(superscript 4+). Ce(superscript 3+) sensitizes Er(superscript 3+) and enhances the luminescence intensity of the doped nanorods remarkably and energy transfer from Ce(superscript 3+)→Er(superscript 3+) was observed.

对发光机理的初步研究表明：发光分别对应于Er(上标 3+)的2H(下标 11/2)→4I(下标 15/2)，4S(下标 3/2)→4I(下标 15/2)跃迁，铈离子以Ce(上标 3+)和Ce(上标 4+)两种形式存在于体系中，Ce(上标 3+)对Er(上标 3+)起敏化作用，可以显著增强β-BBO：Er(上标 3+)/Ce(上标 3+)/Ce(上标 4+)纳米棒的发光强度，存在Ce(上标 3+)→Er(上标 3+)的能量传递过程。

Western culture, red is a derogatory very strong word,"fire" and "blood" Legend, It symbolizes the brutal, bloody, if (1) The red rules oftooth and claw carnage and violence rule.(2) red revenge bloody revenge,(3) ared battle bloody war; It symbolizes the radical, violent revolution. if (1) red hotpolitical campaign heated political campaigns,(2) a red revolution Red revolution.(3) red radical leftist activities; It also symbolizes danger, tension, if (1) red alert air-raid alarm.(2) a red adventure story of a tense adventure story.(3) a red flag warning flags; It also symbolizes debauchery, obscenity, if (1) a red waste of his youth because of his youthful debauchery and wasteful.(2) Huajieliuhang ared light district.(3) Is she really sored as she is painted?

西方文化中的红色则是一个贬意相当强的词，是&火&、&血&的联想，它象征着残暴、流血，如（1）The red rules oftooth and claw残杀和暴力统治，（2）red revenge血腥复仇，（3）ared battle血战；它又象征激进、暴力革命，如（1）red hotpolitical campaign激烈的政治运动，（2）a red revolution 赤色革命，（3）red activities左派激进活动；它也象征危险、紧张，如（1）red alert空袭报警，（2）a red adventure story一个令人紧张的冒险故事，（3）a red flag危险信号旗；它还象征着放荡、淫秽，如（ 1）a red waste of his youth他那因放荡而浪费的青春，（2）ared light district花街柳巷，（ 3）Is she really sored as she is painted？

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐