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991.
Ronge Xing Chaojie Xu Kun Gao Haoyue Yang Yongliang Liu Zhaoqian Fan Song Liu Yukun Qin Huahua Yu Pengcheng Li 《Molecules (Basel, Switzerland)》2021,26(9)
In this paper, chitooligosaccharides in different salt forms, such as chitooligosaccharide lactate, citrate, adipate, etc., were prepared by the microwave method. They were characterized by SEM, FTIR, NMR, etc., and the nitric oxide (NO) expression was determined in RAW 264.7 cells. The results showed that pure chitooligosaccharide was an irregular spherical shape with rough surface, and its different salt type products are amorphous solid with different honeycomb sizes. In addition to the characteristic absorption peaks of chitooligosaccharides, in FTIR, the characteristic absorption of carboxyl group, methylene group, and aromatic group in corresponding acid appeared. The characteristic absorption peaks of carbon in carboxyl group, hydrogen and carbon in methyl, methylene group, and aromatic group in corresponding acid also appeared in NMR. Therefore, the sugar ring structure and linking mode of chitooligosaccharides did not change after salt formation of chitooligosaccharides. Different salt chitooligosaccharides are completely different in promoting NO secretion by macrophages, and pure chitooligosaccharides are the best. 相似文献
992.
Simon G. Bott Alan P. Marchand Kaipenchery A. Kumar D. Vidyanand Dongxia Xing William H. Watson Ram P. Kashyap Richard A. Sachleben 《Journal of chemical crystallography》1995,25(10):633-640
The crystal structures of three compounds formedvia nucleophilic attack of a heterocyclic secondary amine on PCU-8,11-dione, with the concomitant intramolecular attack of one keto oxygen on the carbon of the other ketone, are presented. In all three compounds, the bridging oxygen contains substantial p-character, and the bonds to the attacking nitrogen are significantly shorter than would be expected. 相似文献
993.
Junyi Gong Peifa Wei Yuanan Su Ying Li Xing Feng Jacky W. Y. Lam Dongzhou Zhang Xiangzhi Song Ben Zhong Tang 《中国化学快报》2018,29(10):1493-1496
Three salicylaldehyde Schiff base (SSB) with AIE behavior were designed and facilely synthesized through a condensation reaction. In solid and aggregation states, these SSB dyes exhibited yellow to red emission with large Stokes shift. One of SSB dyes could specifically stain lipid droplets in living cells. 相似文献
994.
Bin Zhou Faridoon Xiaobo Tian Jian Li Dongliang Guan Xing Zheng Yu Guo Wei Huang 《中国化学快报》2018,29(7):1123-1126
Here, we reported a new approach of on-resin peptide ligation using C-terminal benzyl ester as the stabilized precursor of thioester, which enables both N-terminal elongation and C-terminal peptide ligation on a Rink Amide resin. 相似文献
995.
Huimin Zhang Tingjun Zhong Mei Chen Lanying Zhang Xing Liu Hui Cao 《Liquid crystals》2018,45(8):1118-1128
Effects of the content of fluorinated alkene-terminated liquid crystal (LC) molecules on the physical properties of the fluorinated alkene-terminated LC/E8 mixture were studied. The morphology and electro-optical properties as they doped in polymer-dispersed liquid crystal (PDLC) films were investigated. The detailed discussion of the obtained results is given. As a result, comparing with the physical properties of the series of LC mixtures with the same content of the analogous fully saturated compounds doped with E8, we find that the birefringence is significantly larger for the LC mixture with the alkene-terminated materials. Both fluorinated alkene-terminated LC molecules and the analogous fully saturated compounds doped with E8 reduce the driving voltage of PDLC films. Moreover, PDLC films with the fluorinated alkene-terminated LC molecules possessed higher contrast ratio and faster response time than that of the PDLC films prepared by adding the same mass fraction of the analogous fully saturated compounds. Thus, the ability to manipulate physical properties of LC mixture and electro-optical properties of PDLC films by changing the LC molecular structures may have future relevance for new LC structures design and applications of PDLC films. 相似文献
996.
Xing Ai Guo Chen Ling Zhang Lei Liu Xiao-Shan He Zhi-Bing He Kai Du 《Plasma Chemistry and Plasma Processing》2018,38(1):281-292
A glow discharge polymer (GDP) was fabricated using trans-2-butene (T2B) and hydrogen (H2) via a plasma-enhanced chemical vapor deposition (PECVD) system. The uniformity of the GDP films was significantly affected by the radial distribution of the H2/T2B plasma parameters. The plasma properties while discharging by a multi-carbon gas source of mixed H2/T2B were investigated during the GDP deposition process. The main positive ions and ion energy distributions in inductively coupled H2/T2B plasmas were analyzed by energy-resolved mass spectrometer (MS), and the electron density and the effective electron temperature were mainly analyzed using a Langmuir probe. The MS results show that the main positive ions in the plasmas are \({\text{C}}_{ 2} {\text{H}}_{ 4}^{ + }\), \({\text{C}}_{ 2} {\text{H}}_{ 6}^{ + }\), \({\text{C}}_{ 3} {\text{H}}_{ 3}^{ + }\), \({\text{C}}_{ 3} {\text{H}}_{ 6}^{ + }\), \({\text{C}}_{ 3} {\text{H}}_{ 8}^{ + }\), \({\text{C}}_{ 4} {\text{H}}_{ 5}^{ + }\), \({\text{C}}_{ 4} {\text{H}}_{ 1 0}^{ + }\), \({\text{C}}_{ 5} {\text{H}}_{ 5}^{ + }\), and \({\text{C}}_{ 5} {\text{H}}_{ 7}^{ + }\) with mass-to-charge ratios (m/e) of 28, 30, 39, 42, 44, 53, 58, 65, and 67, respectively. For a normalized ion intensity, the relative intensities of saturated CH ions increase with increasing radial distance, while the unsaturated CH ions decrease with increasing radial distance. The ion energy distribution of \({\text{C}}_{ 2} {\text{H}}_{ 6}^{ + }\) (m/e = 30) presents a bimodal structure. Additionally, both the electron density and the effective electron temperature decrease with increasing radial distance. 相似文献
997.
998.
Wenzhang Fang Li Zhou Bin Shen Yi Zhou Qiuying Yi Mingyang Xing Jinlong Zhang 《Research on Chemical Intermediates》2018,44(8):4609-4618
Bi2O2.7/Bi2Ti2O7 composite photocatalyst films are synthesized by sol–gel dip-coating. The ratio of adding Bi and Ti precursors can be controlled during the preparation process. The phase structure is confirmed by X-ray diffraction. The UV–visible diffuse reflectance spectrum shows that the composite catalysts present light absorption in the visible region. The obtained Bi2O2.7/Bi2Ti2O7 composite films possess superior photocatalytic degradation of rhodamine B, owing to the visible light response of Bi2O2.7 and the separation of photogenerated electrons and holes between the two components. As a result, the Bi2O2.7/Bi2Ti2O7 (Bi/Ti = 1:1) displays the highest photocatalytic activity under visible light or UV light irradiation for the degradation of different organic dyes, including methyl blue, methyl orange and acid orange 7. 相似文献
999.
Liang-Cheng ZHAO Jing-Gong WANG Xing LI Shuo ZHANG Zhao-Fa ZHANG Ming-Yue HU Feng LU Yi-Dan WANG Yan-Qiao HU Xiu-Ping GUO Qing-Xue LIU Hua-Jie LIU 《分析化学》2018,46(2):e1801-e1809
Inductively coupled plasma-atomic emission spectrometry/mass spectrometry (ICP-AES/MS) is a potentially powerful tool in chemical phase analysis of gold in batch mode, especially applicable to the low-grade gold ores with gold content of far below detection limit of the other methods, but it has not been used in gold phase analysis of gold ores. In this work, three types of typical gold deposits (altered rock type, quartz vein type, and microscopic disseminated type) and national standard reference materials of gold ores were used to establish and validate a method for gold phase analysis of gold ores using ICP-AES/MS. The optimum conditions of phase analysis were determined, including the sample granularity and preparation procedures, separation absorbent, pretreatment procedures of various phases of gold and optimized instrument parameters. Evaluation of the optimized method showed that this method had acceptable precision (RSD: 1.1%–10.6%) and accuracy (relative error, RE: 0.5%–6.3%), and the detection results of gold in ores were comparable with those obtained using the hydroquinone volumetric method-extraction flame atomic absorption spectrometry (VOL-AAS) and graphite furnace atomic absorption spectrometry (GFAAS) methods. The sum content of gold of the 4 phases (free gold, FAu; linked gold, LAu; sulphide-bearing gold, SAu; and other mineral-bearing gold, AAu) conformed to the total gold content and was consistent with the results of rock-mineral identification. The proposed method had a low detection limit (0.30 ng g–1) and wide linear range (5.0 ng mL–1–20.00 μg mL–1). It is a simple, rapid, and efficient method for gold phase analysis in batch form. 相似文献
1000.
添加Cl离子对VO-WO/TiO催化剂低温NO转化率的影响 《燃料化学学报》2018,46(11):1370-1376
考察添加不同含量Cl离子对浸渍法制备的Cl-V_2O_5-WO_3/TiO_2催化剂低温NO转化率的影响。随着Cl离子质量添加量从0增加到2.5%,Cl-V_2O_5-WO_3/TiO_2催化剂NO转化率先升高后降低,结合在含有SO_2和H2O的SCR实验结果,确定1.5%Cl-V_2O_5-WO_3/TiO_2为性能最优催化剂。在反应温度为149-362℃,NO转化率大于95%;在145-385℃,NO转化率大于90%。采用XRF、BET、XRD、TG、FT-IR和H2-TPR等方法表征了催化剂的物理化学性能和结构。结果表明,在反应气氛中加入SO_2和H2O后,催化剂比表面积和孔容均减小,副反应产物含有NH+4和SO_2-4。适量Cl离子可以抑制硫物种沉积,减少副反应产物生成,增强催化剂抗中毒能力。 相似文献