臧超飞
,
何豫生
,
沈庆飞
,
昌俊
,
李春光
,
张国华
,
罗胜
,
齐志
,
尹道乐
,
丁克俭
低温物理学报
doi:10.3969/j.issn.1000-3258.2001.04.008
我们应用脉冲电流的方法测量了Bi2Sr2CaCu2O8单晶在4特斯拉强场下的大电流时等温E-J特性.我们观察到在大电流时,样品电阻率ρ迅速增大,随着电流的继续上升,经过一段正曲率增长阶段,几乎达到饱和值,最后经过一段负曲率上升,达到正常态,显示出完整的S形.应用尹道乐等人的统一物质方程理论,给出了实验曲线较好的数值拟合.根据拟合结果,讨论了理论中各个参量的物理意义.
关键词:
刘三荣
,
刘靖宇
,
李悦生
应用化学
doi:10.3724/SP.J.1095.2013.30198
以Ph3CB(C6Fs)4/iBu3Al作为助催化体系,研究了单氯半茂型催化剂,ClCp' Zr[X-2-R1-4-R2-6-(Ph2P=0)C6H2]2 (CP'=C5H5,a:X=O,R1=Ph,R2=H;b:X=O,R1=F,R2=H;c:X=O,R1=tBu,R2=H;d:X=O,R1=R2=tBu;e:X =O,R1 =SiMe3,R2 =H;f:X =S,R1=SiMe3,R2 =H;Cp'=C5Mes;g:X=O,R1=SiMe3,R2=H)的乙烯高温(50～125℃)聚合行为.结果表明,催化剂a～d可在高温(50～100℃)下高效引发乙烯聚合,最佳反应温度为75℃.适当增大R1取代基的位阻或引入吸电子取代基均有利于提高催化活性.三甲基硅烷基取代的催化剂e耐高温性能较催化剂a～d大大提升,在100℃时,乙烯聚合活性可达5628 kg/(mol Zr·h).金属中心的配位原子及茂环上取代基团的改变对催化活性和聚合物的相对分子质量分布有一定的影响.
关键词:
单氯单茂锆催化剂
,
乙烯聚合
,
高温高活性
马先伟
,
王培铭
材料科学与工程学报
主要分析了P_2O_5对高C_3S熟料易烧性、矿物组成和强度发展及水化过程的影响.结果发现P_2O_5在1400℃时有效加快了CaO的吸收,使C_3S的形成加快,并诱使了C_3S的多晶转变:在掺量小于2.0%时,由R型(参考熟料)转变为M_1型,当超过2.0%时,又开始出现了M_3型;但这些影响在低于1400℃时很小.加入适量的P_2O_5可以提高熟料的早期强度,但是延缓了水化放热速率和降低了28天强度,当P_2O_5含量高于2.5%时,会有xC_2S-C_3P(x=1～2)生成.综合考虑,P_2O_5的掺量应在1.5%以内.
关键词:
P_2O_5
,
C_3S
,
熟料
,
晶型
,
水化
牛景扬
,
王敬平
,
柏艳
,
党东宾
,
于丽
应用化学
doi:10.3969/j.issn.1000-0518.2000.02.005
由N-甲基吡咯烷酮(NMP)和HnXMo12O40·mH2O(X=P,Si,Ge)合成了具有非线性光学性质的电荷转移盐,(NMPH)3PMo12O40·CH3CN(Ⅰ ),(NMPH)4SiMo12O40·CH3CN(Ⅱ)和(NMPH)4GeMo12O40·CH3CN(Ⅲ),并以元素分析,红外光谱,漫反射电子光谱进行了表征. 结果表明,杂多酸形成电荷转移盐后其阴离子结构未变;N-甲基吡咯烷酮通过N原子与酸中的质子H+结合成阳离子而成盐,在高压汞灯照射下阴阳离子之间可以发生电荷转变. 非线性光学性质研究表明,电荷转移盐的倍频效应强度分别为I2ωⅠ=0.3IKDP ,I2ωⅡ=0和I2ωⅢ=0.02IKDP,三阶非线性系数分别为χ(3)Ⅰ=5.0×10-14esu,χ(3)Ⅱ=3.1×1 0-13esu和χ(3)Ⅲ=4.3×10-13esu.
关键词:
杂多酸
,
N-甲基吡咯烷酮
,
非线性光学性质
刘雪梅
,
邵开文
,
邵润博
人工晶体学报
以钼酸铵和盐酸胍为原料,30％双氧水为氧化剂,在室温下采用常规的水溶液法合成了一种新的单过氧七核钼酸盐(NH4)4(CH6 N3)2[Mo7O23(O2)]·3H2O,通过元素分析、X-射线单晶衍射、红外光谱、固体紫外可见光谱对其进行了表征.标题化合物属于单斜晶系,P21/n空间群,a=1.367(14) nm,b=1.085(11) nm,c =2.748(3) nm,β=93.15(2)°,V=4.0685(7) nm3,Z=4,Dc=2.031g· cm-3,R1 =0.0713,wR2 =0.2199(I＞2σ),GOF=1.03.将合成的过氧钼酸盐(NH4)4(CH6N3)2[Mo7 O23 (O2)]·3H2O作为催化剂用于苯甲醇氧化合成苯甲酸的反应,考察了催化剂用量、氧化剂(30％H2O2)的用量、反应温度、反应时间等对苯甲酸产率的影响.最佳催化反应条件是:n(催化剂)∶n(苯甲醇)=0.063∶1,n(H2O2)∶n(苯甲醇)=40∶1,反应温度85℃,反应时间7h,苯甲酸的产率达到82.2％.
关键词:
过氧钼酸盐
,
合成
,
晶体结构
,
催化氧化
Physics Letters A
The first principles within the full potential linearized augmented plane wave (FP-LAPW) method with the self-interaction corrected (SIC) GGA + U approach were applied to study the compound Of (n-C3H7)(4)N[(FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2). The density of states, the electronic band structure and the spin magnetic moment are calculated. The calculations reveal that the compound has a ferromagnetic interaction between the Fe-III (S = 1/2) and Fe-II (S = 2) ions arising from the bridging dithiooxalato molecule. The spin magnetic moment mainly comes from the Fe-III (S = 1/2) and Fe-II (S = 2) ions with little contribution from 0, S, and C anion. By analysis of the band structure, we find that the compound has metallic property. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
FP-LAPW;electronic structure;spin delocalization;transfer phase-transition;manganese(ii) complex;1d
X. Chang
,
K. Qin and Y.L.Lu Orthodontic Department of Stomatology College
,
China Medical University
,
Sheny ang 110001
,
China
金属学报(英文版)
proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP with t ime in maxillary periodontal ligaments of the rats were studied by immunohistochemistry. The result showed that: magnetic field had dynamic effect and some promotional effect on recove?E F F E C T O F M A G N E T I C F I E L D O N C A L C I T O N I N G E N E- R E L A T E D P E P T I D E I N P E R I O D O N T A L L I G A M E N T S O F R A T S X. Chang , K. Qin and Y. L. Lu Orthodontic Department of Stomatology College , China Medical University , Shenyang 110001 , China Manuscript received 24 June 1999 In order to approach change of C G R P with tim e in periodontal liga m ents of rats in m agneticfield , m axillae of 28 Wistar rats of 6 7 weeks w ere placed in m agnetic fields of per m anentm agnets Nd 2 Fe4 B. Changes of C G R P with tim e in m axillary periodontal liga ments of therats were stu died by i m m unohistoche mistry . The result sho wed that : m agnetic field had dy na m ic effect an d so m e pro motional effect on recovering and reconstruction of the periodontaltissues in it . This provided a better theoretical evidence for clinical use of per m anent m agnets .
关键词:
per m anent m agnet Nd 2 Fe4 B
,
null
,
null
,
null
王建生
,
韩其勇
,
魏寿昆
,
宋波
金属学报
应用Ba蒸气平衡法,在密封Mo反应室内,用自制的TiN和BaS坩埚,进行了纯Fe液中Ba—O,Ba—S,Ba—P平衡的研究。得到反应:BaO_(s)=[Ba]+[O]的标准自由能ΔG°_(wt-％)=188500+38.3T J/mol,e_O~(Ba)=624-1.25×10~6/TBaS_(S)=[Ba]+[S]的标准自由能ΔG°_(wt-％)=469100-111T J/mol,e_S~(Ba)=826-1.64×10~6/T1873K下,反应Ba_3P_2=3[Ba]+2[P]的K_(Ba_3P_2)=7.76×10~(-18),e_(Ba)~P=0.95,ΔG°_(wt-％)=613200 J/mol。
关键词:
Ba
,
O
,
S
,
P
,
liquid iron
,
thermodynamic parameters
党东宾
,
孙继德
,
柏
,
尚伟丽
,
高慧
人工晶体学报
合成了无机-有机杂化晶体[C12H11N2O2][Cd(SCN)3],并采用元素分析、红外光谱表征和单晶X射线衍射分析和热重分析研究.红外光谱分析表明SCN-采用1,3-μ模式.结构分析表明,相邻的Cd(II)原子通过三个1,3-μ-SCN- 阴离子桥连形成无限的[Cd(SCN)-3]∞之字链结构,固体结构中[C12H11N2O2]+阳离子和[Cd(SCN)-3]∞配阴离子形成了分离柱状堆积.该晶体属于单斜晶系P2(1)/c空间群,晶胞参数分别为:a = 1.1260(3) nm, b = 1.5080(4) nm, c =1.1070(3) nm, β= 105.410(10) °, V = 1.8121(8) nm3, Z = 4, dc = 1.840 g·cm3 , T = 293(2) K, μ = 1.571 mm-1, F(000) = 992, R1 = 0.0343, wR2 = 0.0750 [I>2σ(I)]. 热分析结果在180-305 ℃化合物失去一个有机分子,305 ℃以上伴随着镉升华失去三个SCN-阴离子.
关键词:
无机-有机杂化材料
,
镉(II)配合物
,
晶体结构
