检索结果-南通市图书馆

同方期刊数据库博看期刊

Synthesis of tetrahydroisoquinolines through TiCl4-mediated cyclization and Et3SiH reduction

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2020年第3期31卷 729-732页

作者： Zeyu Shi qiong xiao Dali Yin State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia MedicaPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100050China Department of Medicinal Chemistry Beijing Key Laboratory of Active Substances Discovery and Drugability EvaluationInstitute of Materia MedicaPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100050China

A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines(THIQs)is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate *** method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents and allows access to 8-substituted THIQs.

关键词： Tetrahydroisoquinoline TiCl4 Cyclization Et3SiH Telescoped reaction

Preparation of nano-TiO_2 photocatalysts and their decomposition activity in phenol-contaminated water

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1651-1659页

作者： xiao-yuan JIANG Feng DU Chun-xia GUO qiong YANG xiao-ming ZHENG Institute of Catalysis Faculty of Science Zhejiang University Hangzhou 310028 China

ZiO2 was prepared by the hydrolyzation method in （NH4）2SO4-modified TiCl4 solution, and TiO2 photocatalysts were obtained by accelerating the precipitation of TiO2 powder in a high-temperature water bath. The photocatalysts were characterized by Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, Raman spectrum and UV-Vis （Ultraviolet-Visible） spectrometry techniques, and the photocatalytic activity in phenol-contaminated water was investigated. The results showed that photocatalysts calcined at 400 ℃ had a specific surface area of 138.2 m^2/g and an average particle size of 9 nm, and a significant increase in thermal stability of anatase phase. At the calcination temperature of 700 ~C, the crystal form of TiO2 started to change into rutile （anatase： 97%, rutile： 3%）. The activity of TiO2 photocatalysts prepared with （NH4）2SO4-modified TIC14 solution was markedly stronger than that without （NH4）2SOg-modified TIC14 solution. Maximal photocatalytic activity was observed at the mole ratio of Ti：（NH4）2SO4= 1：2, the water-bath temperature of 90℃ and the calcination temperature of 700 ℃.

关键词： Ammonium sulfate Titanium dioxide Photocatalysis reaction Phenol-contaminated water

Beam induced vacuum measurement error in BEPC II

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2011年第S2期54卷 160-163页

作者： HUANG Tao xiao qiong PENG xiaoHua WANG HaiJing Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

When the beam in BEPCII storage ring aborts suddenly, the measured pressure of cold cathode gauges and ion pumps will drop suddenly and decrease to the base pressure gradually. This shows that there is a beam induced positive error in the pressure measurement during beam operation. The error is the difference between measured and real pressures. Right after the beam aborts, the error will disappear immediately and the measured pressure will then be equal to real pressure. For one gauge, we can fit a non-linear pressure-time curve with its measured pressure data 20 seconds after a sudden beam abortion. From this negative exponential decay pumping-down curve, real pressure at the time when the beam starts aborting is extrapolated. With the data of several sudden beam abortions we have got the errors of that gauge in different beam currents and found that the error is directly proportional to the beam current, as expected. And a linear data-fitting gives the proportion coefficient of the equation, which we derived to evaluate the real pressure all the time when the beam with varied currents is on.

关键词： BEPC II vacuum measurement non-linear fitting measurement error negative exponential decay

Primary cutaneous anaplastic large cell lymphoma with overexpressed Ki-67 transitioning into systemic anaplastic large cell lymphoma:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2023年第28期11卷 6889-6894页

作者： Hai-Xi Mu xiao-qiong Tang Department of Hematology The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400010China

BACKGROUND Primary cutaneous anaplastic large cell lymphoma(PC-ALCL)differs from systemic anaplastic large cell lymphoma(sALCL)in cell biological behavior,clinical features,treatment,and ***-ALCL has been reported to rarely transition into sALCL,but the underlying mechanism is not *** we report such a case with certain characteristics that shed light on *** SUMMARY Herein,we report a 43-year-old male with symptoms of a skin nodule and histologically confirmed PC-ALCL with high expression of *** three months of observation,two skin nodules re-appeared with muscle layer involvement and was histologically confirmed as *** months after receiving six cycles of CHOP regimen,the patient had pain in the chest and back,cough,shortness of breath,and night *** was confirmed as relapse of sALCL by immunohistochemistry and several organs,such as the lung were involved as shown by positron emission tomography/computed *** four cycles of DICE plus chidamide regimens followed by auto-hematopoietic stem cell transplantation(ASCT),complete remission(CR)duration was achieved for twelve months while the patient was on maintenance with chidamide(20 mg)*** This case had significantly high expression of Ki-67 when diagnosed as PC-ALCL initially and then transitioned into sALCL,which is ***-ASCT combined with demethylation drugs effectively maintained CR and prolonged progression free survival.

关键词： Cutaneous lymphoma Anaplastic large cell lymphoma Ki-67 Auto hematopoietic stem cell transplantation Case report

Increased reproductive capacity and physical defense but decreased tannin content in an invasive plant

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2011年第5期18卷 521-532页

作者： Wen-Feng Guo Jun Zhang xiao-qiong Li Jian-Qing Ding Key Laboratory of Aquatic Plant and Watershed Ecology Wuhan Botanical Gardenlinstitute Chinese Academy of Sciences Wuhan Graduate School of Chinese Academy of Sciences Beijing Department of Plant Protection Huazhong Agricultural University Wuhan China

Plant invasions create novel plant-insect interactions. The EICA （evolution of increased competitive ability） hypothesis proposes that invasive plants will reallocate resources from defense to growth and/or reproduction because they have escaped from their co-evolved insect natural enemies. Testing multiple herbivory by monophagous and oligophagous herbivores and simultaneous measurement of various plant traits will provide new insights into the evolutionary change ofinvasive plants. In this context, we conducted a common garden experiment to compare plant growth and reproduction, chemical and physical defense, and plant responses to herbivory by different types of herbivores between invasive North American populations and native East Asian populations of mile-a-minute weed, Persicariaperfoliata. We found that invasive mile-a-minnte exhibited lower biomass, flowered earlier and had greater reproductive output than plants from the native range. Compared with native populations, plants from invasive populations had lower tannin content, but exhibited higher prickle density on nodes and leaves. Thus our results partially support the EICA hypothesis. When exposed to the monophagous insect, Rhinoncomimus latipes and the oligophagous insects, Gallerucida grisescens and Smaragdina nigrifrons, more damage by herbivory was found on invasive plants than on natives. R. latipes, G. grisescens and S. nigrifrons had strong, moderate and weak impacts on the growth and reproduction of mile-a-minute, respectively. The results indicate that mile-a-minute may have evolved a higher reproductive capacity in the introduced range, and this along with a lack of oligophagous and monophagous herbivores in the new range may have contributed to its invasiveness in North America.

关键词： chemical defense EICA hypothesis growth herbivory physical defense reproduction

Effect of hydraulic fracturing induced stress field on weak surface activation during unconventional reservoir development

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum Science 2023年第5期20卷 3119-3130页

作者： Jie Bai xiao-qiong Wang Hong-Kui Ge Hu Meng Ye-Qun Wen Unconventional Petroleum Research Institute China University of Petroleum(Beijing)Beijing102249China State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Unconventional reservoirs usually contain many weak surfaces such as faults,laminae and natural fractures,and effective activation and utilization of these weak surfaces in reservoirs can significantly improve the extraction *** hydraulic fracturing,when the artificial fracture approaches the natural fracture,the natural fracture would be influenced by both the original in-situ stress field and the hydraulic fracturing-induced stress *** this paper,the hydraulic fracturing-induced stress field is calculated based on the relative position of hydraulic fracture and natural fracture,the original in-situ stress,the net pressure inside the hydraulic fracture and the pore pressure of the ***,the stability model of the natural fracture is established by combining the Mohr-Coulomb rupture criterion,and extensive parametric studies are conducted to explore the impact of each parameter on the stability of the natural *** validity of the proposed model is verified by comparing with the reservoir characteristics and fracturing process of the X-well 150e155 formation in the Songliao *** is found that the stress field induced by the hydraulic fracture inhibits the activation of the natural fracture after the artificial fracture crossed the natural ***,for similar reservoirs as X-well 150e155,it is suggested to connect natural fractures with hydraulic fractures first and then activate natural fractures which can effectively utilize the natural fractures and form a complex fracture network.

关键词： Hydraulic fracturing Induced stress field Weak surface Natural fracture stability Fracturing characteristics

Investigations on the degradation of aspartame using high-performance liquid chromatography/tandem mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2014年第9期25卷 1259-1264页

作者： Jie-Ping Sun Qiang Han xiao-qiong Zhang Ming-Yu Ding Beijing Key Laboratory for Microanalytical Methods and Instrumentation Department of ChemistryTsinghua University

Aspartame is a widely used sweetener, the long-term safety of which has been controversial ever since it was accepted for human consumption. It is unstable and can produce some harmful degradation products under certain storage conditions. A high-performance liquid chromatography/tandem mass spectrometry method was developed for the simultaneous analysis of aspartame and its four degradation products, including aspartic acid, phenylalanine, aspartyl-phenylalanine and 5-benzyl-3,6- dioxo-2-piperazieacetic acid in water and in diet soft drinks. Aspartame and its four degradation products were quantified by a matrix matched external standard calibration curve with excellent correlation coefficients. The limits of detection were 0.16-5.8 μg/L, which exhibited higher sensitivity than common methods. This method was rapid, sensitive, specific and capable of eliminating matrix interferences. It was also applied to the study of the degradation of aspartame at various pH and temperatures. The results indicated that aspartame was partly degraded under strong acidic or basic conditions and the extent of degradation increased with increasing temperature.

关键词： High-performance liquid chromatography/tandem mass spectrometry Aspartame Degradation productsCola

N-Heterocyclic Carbenes with a Nido-C_(2)B_(9) Carborane Backbone

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第9期39卷 2410-2416页

作者： Zhongzheng Cui Beining Wang Junxia Li Ronglin Pang Yanrui Kang Xu-qiong xiao Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education College of MaterialChemistry and Chemical EngineeringHangzhou Normal UniversityNo.2318 Yu hangtong Rd.HangzhouZhejiang 311121China

The steric and electronic properties of A/-heterocyclic carbenes(NHCs)can be modified by the exocyclic substituents at the nitrogen atoms,by 1-3 atoms'replacements of the five-membered imidazolium skeleton and by the changes of the ***,we report the usage of nido-C_(2)B_(3) carbora ne anions as the backb ones of *** the mixture of sec on dary amino o-carbora nes(lb-le),triethyl orthoformate and HBF4-Et2O results in the unexpected cage-opening of o-carboranes to afford the n/do-C_(2)B_(9) carbora ne anions supported A/-heterocyclic carbene precursors(4b-4e).Deprotonation of 4b with sodium hexamethyldisilazide at-78℃ affords the/V-heterocyclic carbene ligand,which was used to form an Au(I)NHC complex(5).DFT calculations revealed a high-lying lone pair orbitals of the carbene ligands,predicting their strong o-donating abilities.

关键词： Carboranes nido-Carborane anion Carbene ligands Density functional calculations Gold

Zynq-7000 SoC-based portable uncooled infrared imaging system

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Beijing Institute of Technology 2016年第3期25卷 435-440页

作者： PAN Shao-wu LI xiao-qiong HAN Jie School of Life Science Beijing Institute of Technology Beijing 100081 China

A novel portable infrared imaging system based on uncooled focal plane array and programmable system-on-chip（SoC）was *** latest Xilinx Zynq-7000 was used to integrate the main part of the system into a single *** arithmetic units and digital modules were implemented on the programmable logic（PL）of Zynq-7000 to decrease system size and ensure the real-time p nonuniformity correction,while programs running on the processing system（PS）of Zynq-7000 controlled the system work flow and provided human-machine interfaces using open-source software such as Linux and ***,industry standard advanced extendable interface（AXI）buses were adopted to encapsulating standardized IP cores and build high speed data exchange bridges between units within *** results indicate that the image quality and real-time performance of the system can meet application *** it provided a more flexible and extendable solution for evaluating and deploying infrared image enhancement and nonuniformity correction algorithms.

关键词： infrared imaging system uncooled Zynq-7000