共查询到20条相似文献，搜索用时 812 毫秒
1.
WANG Jian-hua LV Zheng-jian XU Shi-rong 《重庆大学学报(英文版)》2005,4(4):223-228
A new series of Schiff base ligands were synthesized by the condensation of 2-amino-5-mercaptan-l,3,4-thiadiazole and salicylaldehyde or 2,4-dihydroxybenzaldehyde and their derivatives with choroacetic acid, and further reaction with corresponding metal acetate to form metal complexes. The compositions and structures of the ligands and their complexes were characterized by elemental analysis, molar conductivities, electronic absorption spectra and infra-red spectra. Their inhibition rates to free radical, such as O2, were also tested. The results show that all of the obtained complexes display significant activities, among which the copper（Ⅱ） complexes have the best inhibitive effects. 相似文献
2.
《天津大学学报(英文版)》2020,(4)
We developed the high-gravity coupled liquid–liquid interface reaction technique on the basis of the rotating packed bed(RPB) reactor for the continuous and ultrafast synthesis of silver sulfi de(Ag_2S) quantum dots(QDs) with near-infrared(NIR) luminescence. The formation of Ag_2S QDs occurs at the interface of microdroplets, and the average size of Ag_2S QDs was 4.5 nm with a narrow size distribution. Ag_2S QDs can disperse well in various organic solvents and exhibit NIR luminescence with a peak wavelength at 1270 nm under 980-nm laser excitation. The mechanism of the process intensifi cation was revealed by both the computational fl uid dynamics simulation and fl uorescence imaging, and the mechanism is attributed to the small and uniform droplet formation in the RPB reactor. This study provides a novel approach for the continuous and ultrafast synthesis of NIR Ag_2S QDs for potential scale-up. 相似文献
3.
Unlike the adverse effect caused by the gelation during crystallization process, gelation of cefpiramide sodium was found to provide ideal product properties, such as a larger and more regular crystal shape. The causes of the gelation phenomenon and the mechanism of gel–crystal transition during the crystallization of cefpiramide sodium were both investigated in this work. The gel was formed due to the strapping of the solvents by the networks of cefpiramide sodium molecules. The whole gel–crystal transition process was divided into the following three stages:(1) when the temperature decreased, the system reached a metastable-state gelation;(2) the initial microcrystal in the gel grew slowly because of the low supersaturation; and(3) the gel finally disappeared, and a larger and more regular crystal was formed. The Hansen solubility parameters were used to analyze the effects of the solvents on this gelation; the analysis results can serve as guidance for solvent screening in the actual production process. 相似文献
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5.
Using carbon tetrachloride （CCl4） as extraction agent, the activated sludge from Tianjin Jizhuangzi Sewage Treatment Plant as inoculum, the test study on biodegradability of lubricants was carried out. The test flasks containing the mineral medium, the test oil and the inoculum were placed in incubation together with flasks containing poisoned blanks for periods of 0 and 21 days, respectively. Flasks containing the reference materials in place of the test oil were run in parallel. At the end of the incubation period, the contents of the flasks were subjected to sonic vibration, and were acidified and extracted by using CCI4. The extracts were then analysed by infra-red （IR） spectrometer to measure the maximum absorption of the C-H stretch of CH2-CH3 band at wavelength of 2 930 cm^-1. The absorption values were used to calculate the residual oil contents of the poisoned and test flasks. Consequently the biodegradability of the test oil was calculated. The test results indicate that the differences in the biodegradability of test materials in different tests are within 5.5%, and consistent with the data described in Coordinating European Council （CEC） L-33- A-93. The biodegradability of lubricants can be evaluated by this method effectively. 相似文献
6.
The effect of CaF2-doped ZrO2 catalyst for the synthesis of dimethyl carbonate （DMC） was studied by X-ray diffraction （XRD）, CO2-temperature programmed desorption （TPD）, Raman spectra, and X-ray photoelectron spectroscopy （XPS）. Catalytic performance was evaluated in the bath and distillation reactors. Results showed that the CaF2/ZrO2 catalysts had activity and stability for DMC synthesis. 相似文献
7.
Density function M06 method has been used to optimize the geometries of camptothecin-cytosine at 6-31+G* basis.Finally, thirteen stabilized complexes have been obtained.Theories of atoms in molecules (AIM) and natural bond orbital (NBO) have been utilized to investigate the hydrogen bonds involved in all the complexes.The interaction energies of all the complexes are corrected by basis set superposition error (BSSE).By the analysis of complexes interaction energy, charge density, second-order interaction energies E(2), it is indicated that the complex 6 is the most stable structure. 相似文献
8.
1, 3：2, 4-di-p-methylbenzylidene-D-sorbitol （MDBS） is known to be an efficient sorbitol derivative gelator. Two new sorbitol derivative gelators were designed and synthesized in contrast to MDBS in order to study the gel properties of gelators with different structures. Their gelation behavior to 30 solvents was investigated. It was found that the gelation behavior was related to the molecular structure of gelators. Compared with MDBS, the gelator with more hydroxyl in the molecular structure could gel water and that with more aromatic ring could gel aromatic solvent. The fibrous and three-dimensional network of the gels was obtained by scanning electron microscopy （SEM）. Ultraviolet-visible （UV-Vis） spectroscopy revealed that π-π interaction was one of the main driving forces for the formation of gels. The π-π stacking of gelation increases with the number of aromatic rings in the molecular structure of gelator. Fourier transform infrared （FT-IR） spectroscopy revealed that the hydrogen bonding was also the main driving force for the formation of gels. The layered structure of the gels was studied by X-ray diffraction （XRD）. 相似文献
9.
Type Ⅰ,Ⅲ and Ⅴ collagens were extracted from bovine dermis and cornea by using pepsin treatment in acetic acid solution,followed by salt precipitation and dialysis,to purify and isolate each type of collagens.The preparation process was analyzed by using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).A reducing agent,2-mercaptoethanol,was used to remove disulfide bonds and analyze the structure of the bonds involved between α chains in some types of collagens.The use of delayed reducing methods resulted in the difference between α1(Ⅲ) and α1(Ⅰ) chains in a mixture containing type Ⅰ and Ⅲ collagens.The structure of disulfide bonds among α chains exists potentially in type Ⅴ collagen prepared from the pepsin-treatment extraction at 4℃,which differs from type Ⅲ collagen in relation to the locations of disulfide bonds.Compared with pepsin-treated collagen at 4℃,the relative molecular weights of α1(Ⅴ) and α2(Ⅴ) chains treated at room temperature decrease by 4.6% and 6.0%,respectively.It is concluded that type Ⅰ,Ⅲ and Ⅴ collagens can be prepared from bovine dermis and cornea by the use of pepsin treatment,salt precipitation and dialysis.The interchain disulfide bonds lie potentially near the edges of termini of type Ⅴ collagen molecules in extracellular matrix,and a small number of interchain crosslinks exist in type Ⅴ collagen. 相似文献
10.
In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high temperature. The samples were analysed by using scanning electron microscope (SEM), X-ray diffraction(XRD), energy disperse spectroscopy(EDS), and differential scanning calorimetry(DSC). The optimal conditions for preparation are as follows: the molar ratio of tetrabutyl orthotitanate to triethanolamine is 1∶0.4, and the calcination and expansion temperature is in the range of 650-750 °C. Under such conditions, the expansion volume of composites could reach 98 mL/g, and the mass loss ratio is less than 5%. The analysis shows that lower temperature and smaller particle size of graphite are helpful to the formation of anatase-type of TiO2, but larger particle size will lead to lower mass loss ratio, and higher temperature and larger particle size will lead to higher expansion volume. 相似文献
11.
It is difficult to directly dope europium complexes in gel because the excessive water or high acidic condition may lead to their decomposition. We prepared a novel homogeneous TiO2 gel containing Eu-phen complexes by using an in-situ synthesis method. The formation of Eu-phen complexes in sol-gel derived TiO2 was confirmed by luminescence excitation spectra. The effects of temperature and aging time on in-situ synthesis are discussed. The luminescence spectra of gel containing europium complexes were also compared with the pure Eu-phen complexes. 相似文献
12.
以4-正戊基苯甲酸(PBA)为第一配体,2,2'-联吡啶(bipy)为第二配体,合成了铕、铽的三元配合物,Eux Tb(1-x)(PBA)3bipy(x=1.0,0.7,0.5,0.3,0.0).并通过UV、IR、元素分析和稀土络合滴定对其结构进行了表征.用荧光分光光度计研究了配合物的荧光性能以及Eu3+、Tb3+之间... 相似文献
13.
尹伟 《广东教育学院学报》2005,25(3):61-66
稀土元素铕与双Schiff碱N，N’-二(亚水杨基)-1，4-二氨基丁烷(L1)、N，N-二(亚水杨基)-1，5-二氨基戊烷(L3)和双Schiff碱还原产物N，N'-二(水杨基)-1，4-二氨基丁烷(L2)形成配合物的荧光是以配体发光为主．当双Schiff碱和TTA共存于同一配合物时，配体的协同发光效应使得络合物的发光表现为强的Eu^3 特征光谱，其最大荧光量子产率为0．21．络合物的能量传递过程主要是由配体的n→π^*跃迁吸收辐射能并直接向中心离子转递能量，中心离子被激发至激发态^5LJ(J=10，8，7，5)，然后无辐射弛豫至^5D0，发生^5D0→^7FJ(J=0，1，2，3，4)的跃迁，发射出Eu^3 特征光谱．络合物Eu(Lx)(TTA)(NO3)3(x=1，3)分子发光器件是由络合物中配体的苯环和噻吩环——天线的底座，S、O和N原子——接受光信号的原子天线和中心Eu^3 离子——原子信号发射器所组成． 相似文献
14.
MCM-41和HMS孔内组装[Eu(bpy)2]3+及其光致发光性质 总被引：1，自引：0，他引：1
采用浸渍的方法在MCM-41和HMS介孔材料孔内组装[Eu(bpy)2]3 (bpy:2,2-联吡啶).所得介孔复合材料经XRD、ICP等离子发射光谱、IR、N2吸附实验及光致发光谱进行了表征.实验结果表明:与介孔材料母体相比,组装稀土配合物后的介孔复合材料的BET比表面积、孔径和孔容均有所下降;组装稀土配合物的介孔复合材料在氙光源激发下,均发射出特征的Eu3 光致发光谱;与组装稀土配合物的HMS介孔复合材料相比,组装后的MCM-41介孔复合材料具有较高的光致发光效率.MCM-41介孔材料是一种比HMS合适的载体,有助于增强介孔材料孔内组装稀土配合物的光致发光效率. 相似文献
15.
TiO2纳米膜紫外可见光谱研究 总被引：1，自引：0，他引：1
采用反胶束法制备TiO2纳米溶胶，利用浸渍提拉方法制备TiO2薄膜，通过对膜进行紫外可见光谱分析，探讨了影响TiO2纳米膜厚度和禁带宽的各种因素．实验结果表明：溶液的配比、陈化时间、热处理温度、涂覆次数等都将直接影响二氧化钛薄膜的紫外光谱和禁带宽． 相似文献
16.
稀土掺杂纳米TiO2的合成研究 总被引：1，自引：0，他引：1
以钛酸四丁酯和硝酸钇为原料 ,采用溶胶—凝胶法制备了掺杂Y的TiO2 纳米材料 ,通过XRD、TEM对产物的晶体结构、晶粒大小、形貌进行了表征 ,TG -DTA研究了TiO2 在锐钛型和金红石型之间的晶型转变过程。结果表明 ,产物为纳米微粒 ,平均粒径为 30nm左右。 相似文献
17.
量子尺寸TiO/SiO2复合微粒的制备与光催化性能研究 总被引：1，自引：0，他引：1
采用改进的溶液－凝胶方法，制备出TiO2及不同配比的TiO2／SiO2粉末，利用XRD，BET，UV－vis等手段研究了微粒的表面结构形态变化，以及对污染物NO2^-光催化降解的影响。研究表明，TiO2／SiO2复合微粒的光催化活性明显高于TiO2微粒，并且质量比m(Ti):m(si)=2:1时催化降解NO2^-最佳。制得TiO2微粒以锐钛型高度分散在TiO2网络中，粒径约12nm，并与TiO2形成Si-O-Ti桥氧结构，提高了TiO2微晶的热稳定性，UV－vis吸收光谱显示复合微粒的光谱吸收发生蓝移，极利于吸附降解NO2^-。 相似文献
18.
采用sol-gel法制备了锐钛矿型TiO2薄膜与Ni2＋掺杂TiO2薄膜。通过XRD、AFM表征了薄膜的晶相和形貌特征,用接触角测定仪测定接触角以评估薄膜的亲水性,以甲基橙作为有机污染物研究了薄膜的光催化性能。实验结果发现：少量Ni2＋掺杂提高了TiO2薄膜的亲水性和光致亲水性。但Ni2＋掺杂却使TiO2光催化性能有所降低。结果表明,TiO2薄膜表面的光致亲水性与光催化特性无正相关性。 相似文献
19.
以钛酸四正丁酯、无水乙醇为原料,微波加热法制备Ti O2溶胶,采用浸渍提拉法,在普通玻璃上镀膜,对其防雾性能进行测试.结果表明:微波场作用使反应体系均匀迅速地升温,加快了反应速度,大大提高了实验效率.与常规水热合成相比,微波合成在较短的时间内形成了Ti O2溶胶,且防雾效果良好. 相似文献
20.
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