检索结果-南通市图书馆

Chinese Physics Letters 2019年第4期36卷 31-34页

作者： Ju-Geng li Sen-Miao Yang Xin Chen Nai-feng Zhuang Qi-Biao Zhu An-hua Wu Xian lin Guo-Hong ma Zuan-Ming jin jian-Quan Yao Department of Physics College of Sciences Shanghai University College of Chemistry and Chemical Engineering Fuzhou University Shanghai Institute of Ceramics Chinese Academy of Science STU & SIOM Joint Laboratory for Superintense Lasers and the Applications College of Precision Instrument and Opto-electronics Engineering Institute of Laser and OptoelectronicsTianjin University

Terbium scandium aluminum garnet(TSAG) crystals have been widely used in magneto-optical systems. We investigate the complex refractive index of the TSAG crystal in the terahertz frequency range using terahertz(THz) time-domain spectroscopy in the temperature range 100–300 K. It is observed that the refractive index and the absorption coefficient increase with the THz frequency. The refractive index increases with the *** measure the temperature coefficient of the refractive index of the TSAG crystal in the frequency range 0.4–1.4 THz. Furthermore, the loss tangent, i.e., the ratio of experimental values of the imaginary and real part of the dielectric permittivity, is found to be almost independent of frequency. TSAG is very promising for applications in THz optoelectronics because it has a high dielectric constant, low loss, and low thermal coefficient of the dielectric constant.

关键词： Dielectric Characterization Crystal

Surface Oxidation Properties in a Topological Insulator Bi_(2)Te_(3)Film

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2013年第10期30卷 136-138页

作者： GUO jian-hua QIU feng ZHANG Yun DENG Hui-Yong HU Gu-jin li Xiao-Nan YU Guo-lin DAI Ning National Laboratory for Infrared Physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083

Bi_(2)Te_(3)films are grown on(111)-oriented GaAs substrates by using the hot wall epitaxy method and the surface oxidation properties in the films are investigated by x-ray photoelectron spectroscopy,Raman spectroscopy,and x-ray *** results show that the films are c-axis *** pairs of new peaks in the XPS spectra involved with the binding energies from Bi 4f and Te 3d electrons correspond to Bi–O–Te *** the A^(1)_(1)g,E^(2)g and A^(2)_(1)g vibration modes from Bi_(2)Te_(3)films,two new peaks at 93.5 cm^(-1)and 123 cm^(-1)are observed in Raman spectra,which are assigned toα-Bi2O_(3)and TeO_(2),*** results are helpful for analyzing the degradation mechanism of topological surface states in Bi_(2)Te_(3).

关键词： films spectra surface

Heat treatment on phase evolution of Bi-2223 precursor powder prepared by spray pyrolysis method

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

Chinese Physics B 2019年第4期28卷 332-336页

作者： li-Jun Cui Ping-Xiang Zhang jin-Shan li Guo Yan Yong feng Xiang-Hong liu jian-feng li Xi-feng Pan Fan Yang Sheng-Nan Zhang Xiao-Bo ma Guo-Qing liu State Key Laboratory of Solidification Processing Northwestern Polytechnical University National Engineering Laboratory for Superconducting materials (NELSM) Western Superconducting Technologies (WST) Co.Ltd. Superconducting materials Center Northwest Institute for Nonferrous Metal Research

The phase evolution of Bi-2223 precursor powder prepared by spray pyrolysis method is studied with different heat treatment parameters. The results show that the reaction temperature and phase composition of precursor powder depend on heat treatment atmosphere. Phase assemblage of(Bi,Pb)-2212, AEC, CuO, and small Bi-2201 can be obtained by heat-treated in N2-0.1%O_2 atmosphere. For precursor powder, there is sufficient reaction process at 770℃, and the dimension of Bi-2212 phase increases rapidly with the increase of heat treatment temperature and time. The dimension of AEC phase also increases by extending heat treatment time. As a balance among phase assemblage, dimension of particle and adequate reaction, a reasonable precursor powder can be obtained by heat-treated at 770℃ for 12 h–16 h in N2-0.1%O_2 atmosphere. Critical current of 37-filament Bi-2223 tape is about 120 A, which confirms that these heat treatment parameters are reasonable.

关键词： Bi-2223 phase evolution heat treatment spray pyrolysis

在线全文

学校读者我要写书评

暂无评论

丹玉和脉颗粒对小鼠的急性毒性实验研究

时珍国医国药 2024年第2期35卷 349-351页

作者：李云凤芦波桂明泰周训杰姚磊李建华王明珠马玉龙陈晓喆侯春蕾史鑫鑫符德玉上海中医药大学附属岳阳中西医结合医院上海200437

目的观察丹玉和脉颗粒对小鼠的急性毒性。方法分别给予丹玉和脉颗粒不同浓度和0.5%CMC-Na溶液灌胃给药后,连续观察14天,记录小鼠的一般情况、体质量、耗食量及主要脏器外观形态有无异常表现,并记录小鼠中毒表现及死亡情况。结果急性毒... 详细信息

目的观察丹玉和脉颗粒对小鼠的急性毒性。方法分别给予丹玉和脉颗粒不同浓度和0.5%CMC-Na溶液灌胃给药后,连续观察14天,记录小鼠的一般情况、体质量、耗食量及主要脏器外观形态有无异常表现,并记录小鼠中毒表现及死亡情况。结果急性毒性实验中,丹玉和脉颗粒各剂量组均未见小鼠中毒表现及死亡,给药前后小鼠的一般情况、体质量、耗食量、各脏器指数均无明显差异。结论在9~36 g/kg的剂量范围内,丹玉和脉颗粒对小鼠的一般情况、体质量、耗食量及主要脏器均无明显影响。急性毒性试验提示该药毒副作用较小,安全性良好,为临床安全用药提供依据。

关键词：丹玉和脉颗粒急性毒性小鼠高血压

Ruminal in situ disappearance kinetics of six nutritive ingredients in leaves and stems of young tetraploid black locust in growing steers

在线全文

学校读者我要写书评

暂无评论

Forestry Studies in China 2009年第3期11卷 168-173页

作者： jianG jin-zhong SUN Peng li Yun ZHANG Guo-jun liU jian-hua HAN feng-bao NIU Chen College of Biological Sciences and Biotechnology Beijing Forestry University Key Laboratory of Genetics and Breeding of Forest Trees and Ornamental Plants of Ministry of Education Beijing 100083 P. R. China Department of Chemistry Guizhou Normal College Guiyang 550018 P. R. China Forestry Bureau of Xianghe County Hebei Province Xianghe 065400 P. R. China Department of Plant and Soil Science Texas Tech University Lubbock 79409 USA

Tetraploid black locust （Robinia pseudoacacia） is a woody plant with larger leaves and richer nutritional content than normal diploid black locust, with greater biomass and wider adaptability than herbaceous plant forage. However, currently no stock- breeders have adopted it as a major forage in China and other countries for a lack of information on the evaluation of nutritional ingredients of leaves and stems of young tetraploid black locust （YTBL） by in situ digesting tests. The objectives of this study were： 1） to assess the nutritive value of YTBL that bourgeoned from root stumps in the spring by determining the ruminal in situ disappearance kinetics of dry matter （DM）, organic matter （OM）, crude protein （CP）, ether extract （EE）, neutral detergent fiber （NDF） and acid detergent fiber （ADF） from leaves, stems and a mixture of both leaves and stems （MLS） of YTBL; 2） to compare these kinetic estimates with those of Leymus chinensis, a widely used ruminant forage in China. All samples were evaluated in situ by using five ruminally cannulated crossbred steers （550±22.7 kg BW）. The results of 48 hours, the representative incubation period, indicate that in situ disappearance rates of DM and OM in YTBL leaves, stems and MLS are on average about 40% and can attain the level of digestibility of L. chinensis. In situ disappearance rates of leaves, stems and MLS of YTBL for CP and EE were 41% and 58% respectively, rates higher than those of L. chinensis. But the disappearance rates of NDF and ADF were, on average, respectively 30.62% and 24.89% and lower than those ofL. chinensis. By analyzing synthetically all of our results it could be inferred that MLS of YTBL offers effective ruminal degradability of DM, NDF, ADF, CP, EE and OM, similar to the nutrients of L. chinensis. This supports our contention that the YTBL leaves, stems and MLS are suitable feed for those ruminants requiring high levels of nutrients, such as dairy cows and Boer goats, instead of plant forage, whi

关键词： tetraploid black locust in situ disappearance kinetics ruminant nutritive analyses

Higher CO_2-insufflation pressure inhibits the expression of adhesion molecules and the invasion potential of colon cancer cells

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2009年第22期15卷 2714-2722页

作者： Jun-Jun ma Bo feng Yi Zhang jian-Wen li Ai-Guo Lu Ming-liang Wang Yuan-Fei Peng Wei-Guo Hu Fei Yue Min-hua Zheng Department of General Surgery Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai Minimally Invasive Surgery Center Shanghai 200025 China Shanghai Institute of Digestive Surgery Shanghai 200025 China

AIM： To investigate the influence of CO2-insufflation pressure on adhesion, invasion and metastatic potential of colon cancer cells based on adhesion molecules expression. METHODS： With an/n vitro artificial pneumoperitoneum model, SW1116 human colon carcinoma cells were exposed to CO2-insufflation in 5 different pressure groups： 6 mmHg, 9 mmHg, 12 mmHg, 15 mmHg and control group, respectively for 1 h. Expression of E-cadherin, ICAM-I, CD44 and E-selectin was meas- ured at 0, 12, 24, 48 and 72 h after CO2-insufflation using flow cytometry. The adhesion and invasion capacity of SW1116 cells before and after exposure to CO2-insufflation was detected by cell adhesion/invasion assay in vitro. Each group of cells was injected intraperitoneally into 16 BALB/C mice. The number of visible abdominal cavity tumor nodules, visceral metas-tases and survival of the mice were recorded in each group. RESULTS： The expression of E-cadherin, ICAM-1, CD44 and E-selectin in SWl116 cells were changed significantly following exposure to CO2 insufflation at different pressures （P 〈 0.05）. The expression of E-cadherin, CD44 and ICAM-1 decreased with increasing CO2-insufflation pressure. The adhesive/ invasive cells also decreased gradually with increasing pressure as determined by the adhesion/invasion assay. In animal experiments, the number of abdominal cavity tumor nodules in the 15 mmHg group was also significantly lower than that in the 6 mmHg group （29.7± 9.91 vs 41.7±14.90, P = 0.046）. However, the survival in each group was not statistically different. CONCLUSION： CO2-insufflation induced a temporary change in the adhesion and invasion capacity of cancer cells in vitro. Higher CO2-insufflation pressure inhibited adhesion, invasion and metastatic potential in vitro and in vivo, which was associated with reduced expression of adhesion molecules.

关键词： Adhesion molecule Colorectal cancer Metastasis Pneumoperitoneum Artificial Tumor invasion

正常足月新生儿出生3个月内肠道菌群的定植规律分析

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

贵州医科大学学报 2024年第1期49卷 109-114页

作者：张金铃姜华杨萌婷马丽雷光霞杜欣欣冯梅余涵王鉴贵州医科大学临床医学院贵州贵阳550000 贵州医科大学附属医院小儿外科贵州贵阳550004 贵州医科大学附属医院新生儿科贵州贵阳550004

目的探讨正常足月新生儿出生3个月内肠道菌群的定植规律。方法收集20例正常足月新生儿及其孕母的临床资料,取新生儿出生后第1天(C0)、第3天(C1)、第1周(C2)、第1个月(C3)及第3个月(C4)的粪便标本,采用Illumina NovaSeq PE250进行16S... 详细信息

目的探讨正常足月新生儿出生3个月内肠道菌群的定植规律。方法收集20例正常足月新生儿及其孕母的临床资料,取新生儿出生后第1天(C0)、第3天(C1)、第1周(C2)、第1个月(C3)及第3个月(C4)的粪便标本,采用Illumina NovaSeq PE250进行16S核糖体RNA(16S rRNA)V3+V4区测序,采用生物信息学分析肠道菌群的定植规律。结果正常足月新生儿粪便中肠道菌群的扩增子序列变异体(ASV)数目、Shannon指数于C0时最高;正常足月新生儿出生3个月内的肠道菌群以变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteriota)、拟杆菌门(Bacteroidota)为优势菌门,Proteobacteria相对丰度随日龄由高变低再逐渐增高,Firmicutes与之相反;正常足月新生儿生3个月内优势菌群在属水平的演变依次为罗尔斯通菌属(Ralstonia)、链球菌属(Streptococcus)、双歧杆菌属(Bifidobacterium),随日龄增加,Bifidobacterium相对丰度逐渐升高,C4时达44.18%且为优势菌属。结论正常足月新生儿生3个月内肠道菌群的多样性、组成结构及相对丰度出现变化。

关键词：婴儿新生足月儿肠道菌群多样性相对丰度 16S核糖体RNA

Formation mechanism of twin domain boundary in 2D materials: The case for WTe2

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第3期12卷 569-573页

作者： Guan-Yong Wang Weiyu Xie Dan Xu Hai-Yang ma Hao Yang Hong Lu Hao-hua Sun Yao-Yi li Shuang Jia liang Fu Shengbai Zhang jin-feng Jia Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education) School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy New York 12180 USA Institute of Chemical materials China Academy of Engineering Physics (CAEP) P. O. Box 919-327 Mianyang 621900 China International Center for Quantum materials School of Physics Peking University Beijing 100084 China Department of Physics Massachusetts Institute of Technology Cambridge MA 02139 USA Tsung-Dao Lee Institute Shanghai 200240 China

Our scanning tunneling microscopy (STM) study observes, for the first time, twin domain boundary (TDB) formations on the surface of WTe2 single crystal, which is glued by solidifying indium to Si substrate. In these TDB regions, a large inhomogeneous strain field, especially a critical shear strain of about 7%, is observed by geometric phase analysis. This observation does not obey the old believe that a small mechanical stress is sufficient to drive thermally-induced TDB formations in two-dimensional materials. To resolve the contradiction, we perform density functional theory calculations combined with elasticity theory analysis, which show that TDBs on WTe2 are entirely displacement-induced, for which a critical strain is necessary to overcome the onset barrier.

关键词： twin domain boundary seanning tunneling microscopy (STM) density functional theory strain WTe2

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

黄鳝来源阿氏芽孢杆菌的筛选及发酵条件优化

饲料研究 2024年第3期47卷 73-78页

作者：郑菲菲何鑫尹丽张靖悦祝东梅高坚宋玉峰赵玉华华中农业大学水产学院湖北武汉430070 水产养殖国家级实验教学示范中心(华中农业大学) 湖北武汉430070

试验旨在从人工养殖的黄鳝体内分离高产蛋白酶菌株,为后续微生物蛋白酶的制备和微生态制剂的开发提供菌种资源,以解决黄鳝摄食率低、消化不完全及水体氮污染等问题。通过采用脱脂奶粉培养基透明圈法初筛和Folin-酚法测定酶活复筛相结合... 详细信息

试验旨在从人工养殖的黄鳝体内分离高产蛋白酶菌株,为后续微生物蛋白酶的制备和微生态制剂的开发提供菌种资源,以解决黄鳝摄食率低、消化不完全及水体氮污染等问题。通过采用脱脂奶粉培养基透明圈法初筛和Folin-酚法测定酶活复筛相结合的方式筛选人工养殖黄鳝肠道中的高产蛋白酶菌株,通过溶血试验与药敏试验检测菌株安全性,并进行常规生化和分子生物学鉴定。通过单因素和正交试验优化其发酵条件,筛选到一株高产蛋白酶、产过氧化氢酶的菌株ma-4,初步鉴定其为阿氏芽孢杆菌(Bacillus aryabhattai)。该菌株最适产酶条件为发酵时间48 h、发酵温度36℃、可溶性淀粉添加量15 g/L、牛肉浸粉添加量15 g/L和pH值6.0。优化后菌株酶活力为288.14 U/mL,较优化前提高了3.34倍。研究表明,菌株ma-4为高产蛋白酶、产过氧化氢酶、不溶血、不耐药的阿氏芽孢杆菌,该菌株为开发黄鳝微生态制剂开拓了菌种资源。

关键词：黄鳝阿氏芽孢杆菌筛选鉴定安全性评价发酵条件优化

抗生素暴露对极早产儿出生后不同时间肠道菌群定植的影响

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

贵州医科大学学报 2024年第8期49卷 1205-1211页

作者：冯梅张金铃姜华杨萌婷马丽雷光霞杜欣欣余涵王鉴贵州医科大学附属医院新生儿科贵州贵阳550004 中山大学附属第一医院贵州医院新生儿科贵州贵阳550032 贵州医科大学附属医院小儿外科贵州贵阳550004

目的探讨基于16S核糖体RNA(16S rRNA)基因测序技术动态监测抗生素治疗的极早产儿(VPI)出生后不同时间肠道菌群的定植及演变过程。方法选取生后24 h内使用抗生素治疗的VPI(胎龄<32周)20例为研究对象,收集VPI的一般临床资料[性别、胎龄、... 详细信息

目的探讨基于16S核糖体RNA(16S rRNA)基因测序技术动态监测抗生素治疗的极早产儿(VPI)出生后不同时间肠道菌群的定植及演变过程。方法选取生后24 h内使用抗生素治疗的VPI(胎龄<32周)20例为研究对象,收集VPI的一般临床资料[性别、胎龄、出生体质量、分娩方式、胎盘/脐带/羊水情况、喂养方式、抗生素使用种类和持续时间、有无使用呼吸机和使用时间、住院时长,住院期间新生儿肺炎、脓毒症、新生儿呼吸窘迫综合征(RDS)、支气管肺发育不良(BPD)、新生儿颅内出血(IVH)及新生儿坏死性小肠结肠炎(NEC)的发生情况];收集VPI生后第1天(使用抗生素前,A0)、第3天(A1)、第1周(A2)、第1月(A3)及第3月(A4)的粪便标本,采用16S rRNA基因测序技术进行肠道菌群的生物信息学分析肠道菌群扩增子序列变异体(ASV)数目、Chao1指数、shannon指数、菌门和菌属变化特点及表型预测。结果VPI肠道菌群ASV数目、Chao1指数及shannon指数A1时开始下降,随着抗生素的停用及日龄的增加有所恢复;变形菌门相对丰度先增加后减少,厚壁菌门相对丰度先减少后增加,放线菌门在生后处于稳定的低丰度状态、A4时迅速增加;菌属演替依次为明串珠菌属及克雷伯菌属、双歧杆菌属;刚出生时最先定植的是需氧菌和兼性厌氧菌,A4时厌氧菌和兼性厌氧菌成为优势菌群。结论VPI生后抗生素暴露可能会降低肠道菌群的丰富度及多样性,生后3个月内肠道菌群组成结构、相对丰度及表型不断变化。

关键词：早产表型极早产儿抗生素肠道菌群定植多样性 16S核糖体RNA