检索结果-南通市图书馆

Product yields of stabilized Criegee intermediates in the ozonolysis reactions of cis-2-butene, 2-methyl-2-butene, cyclopentene, and cyclohexene

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

Science China Chemistry 2018年第7期61卷 850-856页

作者： Mixtli Campos-Pineda jingsong zhang Department of Chemistry and Air Pollution Research Center University of California

Cavity ring-down spectroscopy(CRDS)was utilized in combination with chemical titration with sulfur dioxide(SO_2)to quantify stabilized Criegee intermediates(s CIs)produced at low pressures(4–20 Torr)in ozonolysis reactions of cis-2-butene,2-methyl-2-butene,cyclopentene,and *** yield of stabilized s CI,acetaldehyde oxide(CH_3CHOO),from cis-2-butene ozonolysis decreased with decreasing pressure and reached to 0.05±0.04 at the zero-pressure *** nonsymmetric alkene 2-methyl-2-butene produced two stabilized s CIs,CH_3CHOO and acetone oxide((CH_3)_2COO),and their total yield decreased with decreasing pressure and reached 0.01±0.03 at the zero-pressure *** cyclopentene and cyclohexene,the s CI yields were essentially constant near zero,as expected of endocyclic *** nascent yields of s CI of various alkenes are compared.

关键词： ozonolysis stabilized Criegee intermediates cavity ring-down spectroscopy

Measurement of aerosol optical extinction using diode laser cavity ringdown spectroscopy

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2013年第20期58卷 2440-2446页

作者： LIU YingDi zhang jingsong Department of Chemistry and Air Pollution Research Center University of California

Accurate measurement of optical extinction of atmospheric aerosols is important for quantifying the direct climate effects of aerosols. A portable cavity ringdown spectrometer utilizing a modulated multimode blue diode laser (linewidth ～0.2 nm) is developed to measure the aerosol optical extinction. Laboratory generated ammonia sulfate particles (<1 μm in diameter) are characterized, with good agreements between the experimental measurements and Mie theory calculations. An optical extinction detection sensitivity of 0.24 Mm-1 (1σ) is achieved. Measurements of ambient aerosols are also carried out. This study demonstrates the feasibility of a compact, multimode diode laser cavity ringdown spectrometer for sensitive measurements of the optical extinction of atmospheric aerosols.

关键词：蓝色激光二极管大气气溶胶光谱测量光腔衰荡消光硫酸铵颗粒 Mie理论检测灵敏度

Determinant representation of Darboux transformation for the AKNS system

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第12期49卷 1867-1878页

作者： HE jingsong zhang Ling CHENG Yi LI Yishen Department of Mathematics University of Science and Technology of ChinaHefei 230026China Department of MathematicsUniversity of Science and Technology of ChinaHefei 230026China Department of MathematicsUniversity of Science and Technology of ChinaHefei 230026China Department of MathematicsUniversity of Science and Technology of ChinaHefei 230026China

The n-fold Darboux transform (DT) is a 2×2 matrix for the Ablowitz-Kaup-Newell-Segur (AKNS) *** this paper,each element of this matrix is expressed by 2n + 1 ranks'*** these formulae,the determinant expressions of eigenfunctions generated by the n-fold DT are ***,we give out the explicit forms of the n-soliton surface of the Nonlinear Schrodinger Equation (NLS) by the determinant of eigenfunctions.

关键词： darboux transformation,AKNS system (Ablowitz-Kaup-Newell-Segur System),determinant,soliton surface.

Preparation of carboxylmethylchitosan and alginate blend membrane for diffusion-controlled release of diclofenac diethylamine

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第4期63卷 210-215页

作者： Xiaoxue Yuan Ran Liu Wenchang zhang Xiaoqiang Song Lei Xu Yan Zhao Lei Shang jingsong zhang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei230026China School of Pharmacy Shenyang Medical CollegeShenyang110034China School of Pharmacy Shenyang Pharmaceutical UniversityShenyang110016China

Controlled drug release technology is becoming a commercially sound methodology of administering pharmaceutical therapies,and it is important to predict and control the release kinetics to fully take advantage of this ***(CMCS)and alginate(SA)blend membranes were successfully prepared by solution casting technique and exposing to acetic acid atmosphere,which induced the protonation of the amino groups of CMCS,and the formation of polyelectrolyte composite *** using diclofenac diethylamine as the model drug,the diffusion controlled drug release behaviors of the membranes were studied based on permeation experiment,which indicated that the swelling rates of the membranes could be adjusted by simply changing the weight ratio of CMCS/SA and effectively changed the release rate of the *** study shows that CMCS/SA blend membranes are promising biomaterials used for modulating the permeation behavior and developing advanced drug delivery systems.

关键词： release composite diffusion

Fengyun Satellites:Achievements and Future

在线全文

学校读者我要写书评

暂无评论

空间科学学报 2010年第5期30卷 468-473页

作者： Wang jingsong zhang Jiashen Tang Yunqiu National Satellite Meteorological Center/National Center for Space Weather China Meteorological Administration Beijing 100081

Chinese meteorological satellite,Fengyun(FY) Satellite,has a polar-orbiting series and a geostationary *** to now,5 polar-orbiting(FY-1A/B/C/D and FY-3A) and 5 geostationary(FY-2A/B/C/D/E) satellites were *** data has been being intensively applied not only to meteorological monitoring and prediction but also to many other fields regarding ecology,environment,disaster,space weather and so *** FY data sharing system,FengyunCast,is now one of the three components of global meteorological satellite information dissemination system,*** first satellite of the new generation polar-orbiting series,FY-3A,was launched on 27 May,2008,demonstrating the FY polar-orbiting satellite and its application completed a great leap to realize threedimensional observations and quantitative *** first of the next generation geostationary series(FY-4) is planned to launch in 2014.

关键词：气象卫星卫星发射数据共享系统信息传播系统极地轨道气象监测空间天气组成部分

REASONING　ON　LIKELIHOOD　RATIOS

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 1997年第1期12卷 27-34页

作者： zhang YAOTING AND DU jingsong

In this paper, the methods based on likelihood ratio are proposed for uncertainty reasoning. The elementary concepts and formulas are derived systematically, especially for the situations with dependent information an...

关键词：

A multiphoton ionization study of acetone using time-of-flight mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第27期55卷 3123-3130页

作者： ZHENG XianFeng WU HongXia SONG Yu WU JingZe zhang jingsong CUI ZhiFeng Department of Physics Anhui Normal University Wuhu 241000 China Department of Chemistry University of California Riverside CA 92521 USA

The 3p Rydberg states of acetone and photodissociation of the acetone cation were studied using time-of-flight(TOF)mass *** 3p Rydberg state spectroscopy of acetone was investigated with linearly polarized two-photon resonance enhanced multiphoton ionization(REMPI)from 320 to 337 *** new transition bands were observed in the *** addition to the CH3COCH3 + ion,CH3CO + and CH3 + fragments were *** laser power dependences suggest that the CH3COCH3 +,CH3CO + and CH3 + ions are produced in three-,four-,and four-photon processes,*** of CH3CO + and CH3 + involves excitation of the ground state acetone cation by an additional photon and subsequent decomposition of the excited acetone *** average translational energies of CH3CO + and CH3 + from dissociation in CH3COCH3 +(X)+hv→CH3CO + +CH3 and CH3COCH3 +(X)+hv→CH3 + +CH3CO,respectively,were derived from the ion TOF peak profiles.

关键词：共振增强多光子电离飞行时间飞行质谱丙酮阳离子 REMPI CH3 线性偏振

蒸汽爆破预处理对猴头菇子实体残渣粗多糖理化性质及调节肠道菌群作用的影响

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

食品工业科技 2025年第1期46卷 61-69页

作者：陈爽刘利平冯杰张劲松杨焱吴迪刘艳芳郭庆彬天津科技大学食品科学与工程学院天津300457 上海市农业科学院食用菌研究所上海201403

为了研究蒸汽爆破(Steam Explosion,SE)预处理对猴头菇子实体残渣粗多糖理化性质及调节肠道菌群的影响,以猴头菇水提残渣为原料,采用常规粉碎和蒸汽爆破两种方式进行处理制备获得粗多糖并进行得率、成分含量、单糖组成、分子量及消化和... 详细信息

为了研究蒸汽爆破(Steam Explosion,SE)预处理对猴头菇子实体残渣粗多糖理化性质及调节肠道菌群的影响,以猴头菇水提残渣为原料,采用常规粉碎和蒸汽爆破两种方式进行处理制备获得粗多糖并进行得率、成分含量、单糖组成、分子量及消化和发酵特性的比较。结果显示,经SE处理所得多糖组分(HCQ)的得率、多糖和β-葡聚糖含量分别达到了13.36%、58.20%和47.93%,是常规粉碎处理所得多糖组分(HCW)的2.18、1.57和1.59倍,表明SE能显著(P<0.05)促进残渣中多糖组分的释放。SE还降低了HCQ的分子量并释放出小分子组分,同时提高了单糖组成中的葡萄糖摩尔百分比。在模拟体外人体粪便发酵过程中,与HCW相比,HCQ明显地(P<0.05)提高了有益菌(如厚壁菌门)的丰度和短链脂肪酸的产量,同时降低有害细菌(如埃希氏-志贺氏菌)的丰度,从而有益于机体健康。该研究为蒸汽爆破技术在猴头菇多糖提取中的应用及HCQ多糖作为潜在益生元发挥调节肠道菌群作用提供依据。

关键词：猴头菇水提残渣蒸汽爆破多糖 β-葡聚糖肠道菌群

同方期刊数据库

Ultraviolet Photodissociation Dynamics of 1-Pentyl Radical

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2018年第4期31卷 439-445,613,614页

作者： Ge Sun Yu Song jingsong zhang Department of Chemistry University of California at Riverside RiversideCA 92521USA

The ultraviolet （UV） photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236-254 nm using the high-n Rydberg-atom time-of-flight （HRTOF） technique. The H-atom photofragment yield spectrum of the 1-pentyl radical shows a broad UV absorption feature peaking near 245 nm, similar to the 2pz→3s absorption bands of ethyl and n-propyl. The center-of-mass translational energy distribution, P（ET）, of the H＋CsH10 product channel is bimodal, with a slow peak at -5 kcal/mol and a fast peak at -50 kcal/mol. The fraction of the average translational energy release in the total available energy, （fT）, is 0.30, with those of the slow and fast components being 0.13 and 0.58, respectively. The slow component has an isotropic product angular distribution, while the fast component is anisotropic with an anisotropy parameter -0.4. The bimodal translational energy and angular distributions of the H＋C5H10 products indicate two H-atom elimination channels in the photodissociation of 1-pentyl：（i） a direct, prompt dissociation from the electronic excited state and/or the repulsive part of the ground electronic state potential energy surface; and （ii） a unimolecular dissociation of internally hot radical in the ground electronic state after internal conversion from the electronic excited state.

关键词： Photodissociation 1-Pentyl Alkyl Decomposition Rydberg Excited state