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991.
将配体吡啶-2,6-二[N-(1′-咪唑基丙基)甲酰胺](L)与苦味酸稀土盐[RE(pic)-3]在甲醇中反应合成了9种吡啶-2,6-二[N-(1′-咪唑基丙基)甲酰胺\]稀土配合物,其结构经元素分析、红外光谱及紫外光谱表征,确定了配合物的结构为REL(pic)3·nCH3OH·H2O(RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Er; n=1或2; pic为苦味酸根)。并采用紫外光谱研究了游离配体对金属离子的识别性能。结果显示:加入稀土金属离子后,L中216 nm处吸收峰消失,202 nm处吸收峰明显增强且红移至213~218 nm处,表明配体对稀土金属离子具有明显的识别能力。 相似文献
992.
DAI Jianan LIU Bengen WEI Zhonglin CAO Jungang LIANG Dapeng DUAN Haifeng LIN Yingjie 《高等学校化学研究》2019,35(2):216-220
A straiglitforward and efficient synthetic method of 2′-(dialkylammo)-l-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 2-(dialkylamino)-5,6-dihydro-4H-naphtho[2,1-e][1,3]oxazin-4-one-derivatives have been developed from a-hydroxy andβ-carbonyl amides and various Vilsmeier salts.A wide range of heterocyclic compounds were obtained in excellent yields(up to 97%),which will provide promising candidates lor chemical biology and drug discovery. 相似文献
993.
YANG Xue WEI Yingcong CHU Xuefeng ZHAO Qi YAN Wenling DONG Chenjun LIU Baijun SUN Zhaoyan HU Wei ZHANG Niaona 《高等学校化学研究》2019,35(4):735-741
Nanocellulose(NCC) was prepared through the acid hydrolysis of microcellulose(MCC) and was reacted with maleic anliydride to obtain carboxyl-functionized nanocellulose(MA-NCCs). The presence of .OH and .SO3H on the surface of rod-like MA-NCC was confirmed by Fourier transfonn infrared spectrometry(FTIR). Sulfonated poly(aryl ether ether ketone ketone)(Ph-SPEEKK) was synthesized with bis(4-fluorophenyl-methanone) and 2-phenylhydroquinone as monomer. MA-NCC/Ph-SPEEKK nanocomposite membranes with different MA-NCCs content were prepared, and their properties were characterized. Compared with Ph-SPEEKK, MA-NCC/Ph-SPEEKK nanocomposite membrane showed better mechanical and thermal properties and higher proton conductivity. The proton conductivity of the composite membrane with 4%(mass fraction) MA-NCCs under 80℃ was 0.095 S/cm. And its tensile strength reached 30.3 MPa, which was 21.2% higher than that of Ph-SPEEKK pure polymer membrane. 相似文献
994.
为了揭示中墩斜支承对连续箱梁力学性能的影响,本文考虑约束扭转和竖向挠曲耦合作用,建立了斜支承连续箱梁的力法方程,并获得了内力和变形的解析式.选取斜支承两跨连续箱梁为数值算例,分别计算了竖向对称和偏心均布荷载作用下的内力和变形,并用ANSYS软件计算了控制截面的弯矩.计算结果表明,本文方法计算的弯矩与ANSYS计算值吻合... 相似文献
995.
996.
利用有限元法对勾形磁场环境下硅单晶Czochralski生长时炉内的传递过程进行了全局数值模拟,磁场强度范围为(0~2.0)T.结果表明:勾形磁场可有效抑制熔体内的流动;随着磁场强度增加,熔体内对流逐渐减弱,加热器功率增大,结晶界面温度梯度在磁场强度为0.05T时略有降低,之后增加;结晶界面形状在磁场强度为0.05T和0.1T时向熔体侧弯曲,之后随磁场的增加,变得平坦;同时,熔体内的传质机制逐渐转为以扩散为主;结晶界面平均氧浓度随磁场强度的增加而逐渐降低,当磁场强度高于1.0T时,结晶界面氧浓度会略有上升. 相似文献
997.
本文从数学上确定了具体热源的湍流对流中时均热量传递势容耗散的上界和下界,该上界和下界反映了体热源对湍流对流中热量传递势容耗散的影响.其上界表明具体热源的湍流对流中时均热最传递势容耗散不会大于导热情况下时均热量传递势容耗散;其下界表明,给定湍流流场的统计特性,即在某种意义上,粘性耗散一定,这时时均热量传递势容耗散可能达到的下界依赖于体热源和速度的时均值. 相似文献
998.
REN Ji-Rong WEI Shao-Wen XU Dong-Hui DUAN Yi-Shi 《理论物理通讯》2008,50(8):525-528
Based on the complex three-component order parameter model of a spin-triplet superconductor, by using the C-mapping theory, we derive a new equation describing the distribution of the magnetic field for vortices, which can be reduced to the modified London equation in the case of |ψ^2|^2 ~- |ψ^3|^2 = 0 and Wl^1= 1. A magnetic flux quantization condition for vortices in a spin-triplet superconductor is also derived, which is topological-invariant. Fhrthermore, the branch processes during the evolution of the vortices in a spin-triplet superconductor are discussed. We also point out that the sum of the magnetic flux quantization that those vortices carried is 2nФo (Фo is the unit magnetic flux), that is to say, the sum of winding number is even, which needs to be proved by experiment. 相似文献
999.
In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space. The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity. First, new Poisson brackets have been defined in non-commutative phase space. They contain corrections due to the non-commutativity of coordinates and momenta. On the basis of this new Poisson brackets, a new modified second law of Newton has been obtained. For two cases, the free particle and the harmonic oscillator, the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys. Rev. D, 2005, 72: 025010). The consistency between both methods is demonstrated. It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space, but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative. 相似文献
1000.
High-Conversion-Efficiency and Broadband Tunable Femtosecond Noncollinear Optical Parametric Amplifier 下载免费PDF全文
We build a compact high-conversion-efficiency and broadband tunable noncollinear optical parametric amplifier (OPA) in the infra-red (IR) pumped by a femtosecond Ti:sapphire CPA laser. The OPA consists of an internal seed of white-light continuum generator (WLG) and two noncollinear optical parametric amplifiers. The tunable wavelength range is from 1.2μm to 2.4μm for both signal and idle pulses. The total OPA efficiency in the last OPA stage reaches about 40% in a wider tunable spectral range (from 1.3μm to 1.7μm for signal pulse, from 1.5μm to 2.0 μm for idle pulse respectively). 相似文献