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981.
Chromatographia - In this study, a poly(glycidyl methacrylate) nanoparticle (PGMA NP)-coated column system with two antibiotics as selector was constructed for enantioseparation. The PGMA NP... 相似文献
982.
Feng Song Mengyuan Song Haibo Luo Mingkun Xie Xindi Wang Hao Dai Yiping Hou 《Electrophoresis》2021,42(19):1892-1899
Kyrgyz ethnic group is one of the nomads in China, with the majority in Xinjiang and a small part of them living in Heilongjiang province. Historically, they have went through five migrations westward due to the wars. The name “Kyrgyz” means 40 tribes, originating from the primary groups of Kyrgyz. However, it is a largely understudied population, especially from the Y chromosome. In this study, we used a previously validated high-resolution Y-chromosome single nucleotide polymorphisms (Y-SNPs) and short tandem repeats (Y-STRs) system to study Kyrgyz ethnic group. A total of 314 male samples of Kyrgyz ethnic group were genotyped by 173 Y-SNPs and 27 Y-STRs. After data analysis, the results unveiled that Kyrgyz ethnic group was a population with high percentage of both haplogroup C2a1a3a1d∼-F10091 (91/134) and R1a1a1b2a2-Z2124 (109/134), which has never been reported. This implied that Kyrgyz ethnic group might have gone through bottleneck effects twice, with these two main lineages left. Mismatch analysis indicated that the biggest mismatch number in haplogroup C2a1a3a1d∼-F10091 was 10, while that of haplogroup R1a1a1b2a2-Z2124 was 20. This huge difference reflected the different substructure in two lineages, suggesting that haplogroup C2a1a3a1d∼-F10091 might have the least admixture compared to the other two lineages. After admixture modelling with other datasets, the conclusion could be drawn that Kyrgyz ethnic group had great genetic affinity with Punjabi from Lahore, Pakistan, which supported that Kyrgyz ethnic group in China was close to central Asian. 相似文献
983.
Yan Meng Ding Congcong Shu Xiaoyan Liu Yi Yang Jingjun Wei Guilin Zhang Zhentao Xie Yi Lu Xirui 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):401-410
Journal of Radioanalytical and Nuclear Chemistry - To long-term immobilization of secondary iodine-waste, iodine loaded silver-coated silica-gel (AgIs), glass-powder was used to directly solidify... 相似文献
984.
Xie Linbei Li Ao Zhou Sijie Zhang Min Ding Yi Wang Ping 《Research on Chemical Intermediates》2021,47(6):2373-2391
Research on Chemical Intermediates - Ag/AgCl/ZnTiO3 nanohybrids were assembled by the photoreduction–precipitation assisted with ultrasonic method. Rhodamine B (RhB), methylene blue (MB) and... 相似文献
985.
贵金属物种(Rh或Ir络合物)在均相羰基化和氢甲酰化催化过程得到了广泛的应用,但始终存在分离繁琐等问题,其均相多相化可很大程度上简化分离操作,故一直广受重视.单位点催化剂因其具有可与均相相比拟的较高金属利用率和选择性而成为均相多相化的重要研究方向之一.研究发现,在碘物种存在的情况下用于固载金属物种的配位键容易断裂,进而导致金属物种的流失,而通过离子键固载的[Rh(CO)2I2]–物种更加稳定,比如著名的甲醇羰基化“AceticaTM”工艺中,[Rh(CO)2I2]–负一价阴离子物种是以离子键的方式固定在带有阳离子骨架的甲基化聚乙烯吡啶树脂上.与甲醇羰基化过程类似的乙醇羰基化过程是生产重要化工中间体丙酸的主要途径之一,但该过程的均相多相化始终存在着稳定性差这一关键问题.为了解决这一问题,基于之前将固载于季鏻盐聚合物的[Rh(CO)I3]2–应用于甲醇羰基化的工作,我们将类似的季鏻盐聚合物固载Rh基催化剂Rh-TPISP用于多相乙醇羰基化过程,通过多种表征进一步证明了Rh物种和P物种结构,并提出了“双离子键”模型.P的K边XANES证明了聚合物TPISP的季鏻化阳离子骨架特征.HAADF-STEM测试表明Rh-TPISP中的Rh呈现单位点分散的状态.Rh的XPS和XANES结果证明了Rh-TPISP中Rh物种的价态介于0~+1.通过EXAFS的拟合解析给出了[Rh(CO)I3]2–活性中心结构.由于[Rh(CO)2I2]–为经典的羰基化活性中心,为了进一步证明该结构的正确性,我们将Rh-TPISP的EXAFS和IR谱图与标样[PPh3Et]+[Rh(CO)2I2]–对比发现:在EXAFS谱图中,Rh-TPISP中的Rh-C峰高低于[PPh3Et]+[Rh(CO)2I2]–的Rh-C峰高,而Rh-TPISP中的Rh-I峰高高于[PPh3Et]+[Rh(CO)2I2]–的Rh-I峰高,这就说明Rh-TPISP中Rh物种的Rh-C配位数小于2,而Rh-I配位数大于2;在IR谱图中,标样[PPh3Et]+[Rh(CO)2I2]–中有两个羰基振动峰,与该物种的两个Rh-C配位键相符,而Rh-TPISP中的只有一个羰基振动峰,说明Rh-C配位数为1.因此,Rh-TPISP催化剂的季鏻盐骨架中的每个P物种带有一个正电荷,每个带有两个负电荷的[Rh(CO)I3]2–通过与两个[P]+的静电作用进行固载,形成“双离子键”结构.该催化剂在固定床乙醇羰基化过程中表现出优异的羰基化活性、选择性和稳定性.在3.5 MPa、195 oC反应近1000 h后,Rh-TPISP催化剂TOF保持在约350 h–1,丙酰基选择性为95%以上,高出所有文献报道的均相和多相乙醇羰基化活性.其较高的活性主要是因为[Rh(CO)I3]2–比传统Rh活性相[Rh(CO)2I2]–具有更强的富电子性,而较高的稳定性主要是由于“双离子键”这种强静电作用比“AceticaTM”工艺中“单离子键”更有利于Rh物种的固载.故Rh-TPISP催化剂中的“双离子键”对其优异的催化性能具有极其重要的作用,对后续多相乙醇羰基化的发展具有重要意义. 相似文献
986.
Si Rongrong Wu Chaojun Yu Dongmei Ding Qijun Li Ronggang 《Cellulose (London, England)》2021,28(17):10999-11011
Cellulose - In this study, environmentally friendly TEMPO-oxidized cellulose nanofiber (TO-CNF)/polyvinyl alcohol (PVA)/polyethyleneimine (PEI) nanoparticles were obtained by assembling PEI into... 相似文献
987.
Yufeng Cao Yanmei Chen Zhecheng Zhang Jin Wang Xiaolei Yuan Qin Zhao Yue Ding Yong Yao 《中国化学快报》2021,32(1):349-352
In this communication,a new supramolecualr amphiphile was successfully constructed based on water soluble pillar[5]arene and a unique guest which contain a CO2 responsive tertiary amine unit and a UV responsive coumarin group.When guest molecule 1 dispersed in water,it self-assembled into sheet-like structures.Upon bubbling CO2,1 transformed into 1 H due to the tertiary amine unit was protonated,accompany the nano-sheets transformed into vesicles.Further irradiation of 1 H with 365 nm light for 3 h,the coumarin group reacted with each other to form bola-type amphiphie 2 H.In this case,vesicles collapsed and re-assembled into nano-tubes.However,when addition of WPS into the solution of 1 H,the vesicles transformed into micelles,this is due to the formation of supramolecular amphiphile WP5&1 H.Upon irradiation of WP5&1 H with 365 nm light for 3 h,nano-ribbons observed instead of micelles in the solution.Notably,nanotubes from 2 H could also transform into nano-ribbons after adding WPS.The selfassembly process and the resultant assemblies were characterized by TEM,SEM,DLS,SAXS and NMR technologies.Due to both CO2 and light are "green" for living organisms,we anticipated our system can offer the possibilities in "on demand" drug absorption and release. 相似文献
988.
This study was to investigate the optimal additions of the cellulose decomposition reaction to obtain the most yield of 5-HMF and other furan derivatives in various biphasic systems with FeCl_3-CuCl_2 mixed catalysts,and explore its depolymerization kinetics.A series of controllable reactions have been performed under mild environmentally friendly atmosphere.The experiment results showed that49.13 wt% of 5-HMF was the maximum production along with 2.98 wt% other furan derivatives catalyzed by mixed Lewis acid FeCl_3-CuCl_2 under the two phases which included high concentration NaCl aqueous phase and n-butanol organic phase at 190℃ for 45 min.The conclusion suggested that two-phase systems benefited the yield of 5-HMF,furan derivatives via extracting the target products from reaction phase to organic phase to avoid rehydration of 5-HMF.The kinetic calculation revealed the conversion with mixed catalysts had lower reaction apparent activation energy(21.65 kJ/mol,190-230℃) and the reaction rate was faster than that with acid-based catalysts.Based on experiment exploration,the probable mechanism of cellulose decomposition with FeCl_3-CuCl_2 was proposed. 相似文献
989.
Mingsheng Xu Mingze Sun Sajid ur Rehman Kangkang Ge Xiaolong Hu Haizhen Ding Jichang Liu Hong Bi 《中国化学快报》2021,32(6):2027-2032
The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO) synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g) at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles. 相似文献
990.
A novel good water-soluble macrocycle containing two pyridinium moieties was synthesized in high yield.It could form 1:1 complexes with neutral guests containing naphthalene or phenyl units in water.The water-soluble macrocycle can selectively encapsulate naphthalene to form a 1:1 complex over a variety of polycyclic aromatic hydrocarbons. 相似文献