检索结果-南通市图书馆

Optical Absorption in SiGe/Si Quantum Well Structures Created by Subband Transitions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2001年第12期18卷 1655-1657页

作者： YANG yu MAO Xu YANG Hong-Wei ZHOU Wei ZHOU zhen-Lai LIU Huan-Lin WANG Xun Department of Materials Science and Engineering Yunnan UniversityKunming 650091 Surface Physics Laboratory Fudan UniversityShanghai 200433

The absorption in Si_(1-x)Ge_(x)/Si multiple quantum-well structures is measured. Several separated well absorption peaks corresponding to both intersubband and intervalence band transitions in the samples are observed. In the normal incidence, two broadband peaks are attributed to intervalence band transitions HH0-SO0(2.5μm),HH_(0)-LH_(0)(~ 3μm), respectively. Using 45° incidence of unpolarized light, both the intervalence band and intersubband transitions are observed. The intervalence band transitions (HH_(0)-LH_(0) ) are Ge composition dependent, but the intersubband transitions, HH_(0)-HH_(1) (5.9μm) and HH_(0)-HH_(2)( 4.3 μm), are not sensitive to the Ge composition.

关键词： transitions valence absorption

Marine Atmospheric Boundary Layers Associated with Summer Monsoon Onset over the South China Sea in 1998

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

Atmospheric and Oceanic Science Letters 2010年第5期3卷 263-270页

作者： WANG Dong-Xiao ZHOU Wen yu Xiao-Li XIE Qiang WANG xin Key Laboratory of Tropical Marine Environmental Dynamics＇ South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China Guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and Environment City University ofHong Kong Hong Kong China Weifang Marine andEnvironment Monitor Center Weifang 261401 China

The variations of the marine atmospheric boundary layer (MABL) associated with the South China Sea Summer Monsoon were examined using the Global Positioning System (GPS) sounding datasets obtained four times daily during May-June 1998 on board Research Vessels Kexue 1 and Shiyan 3. The MABL height is defined as the height at the lowest level where virtual potential temperature increases by 1 K from the surface. The results indicate that the MABL height decreased over the northern South China Sea (SCS) and remained the same over the southern SCS, as sea surface temperature (SST) fell for the northern and rose for the southern SCS after the monsoon onset. Over the northern SCS, a decrease in both the SST and the surface latent-heat flux after the onset resulted in a reduction of the MABL height as well as a decoupling of MABL from clouds. It was found that MABL height reduction corresponded to rainfall occurrence. Over the southern SCS, a probable reason for the constant increase of SST and surface heat flux was the rainfall and internal atmospheric dynamics.

关键词： monsoon onset marine atmospheric boundary layer height atmosphere internal dynamics SST

Crystal Structure and Luminescence of a New Two-dimensional Sr(Ⅱ) Coordination Polymer Based on 3,5-Dinitro-salicylic Acid and 1,10-Phenanthroline

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2015年第8期34卷 1295-1299页

作者： KONG Zhi-Guo GUO Sheng-Nan HE Gui-yuan LI xin-Hang JIAO yu-Qi WANG Xiu-Yan Key Laboratory of Preparation and Applications of Environmental Friendly Materials Jilin Normal University Department of Chemistry Jilin Normal University

In this work, we report a new two-dimensional Sr（II） coordination polymer, namely, [Sr（L）（phen）（H20）] （1）, based on 3,5-dinitro-salicylic acid （H2L） and 1,10-phenanthroline （phen）. It crystallizes in monoclinic, space group P2/1 with a = 15.479（3）, b = 9.4020（19）, c = 13.884（3）/k, β= 103.76（3）°, V= 1962.5（7） A3, Z = 4, C19H12SrN4O8, Mr = 511.95, Dc = 1.733 g/cm^3, F（000） = 1024,μ（MoKa） = 2.805 mm^-1, R = 0.0411 and wR = 0.1069. In 1, each L anion bridges three Sr（II） atoms by using carboxylate and hydroxyl groups, yielding a two-dimensional layer structure. The phen ligands are alternately attached to both sides of the layer. The π-π stacking between L and phen in the same layer and hydrogen-bonding interactions between water molecule and carboxylate oxygen atom play an important role in stabilizing the layer structure of 1. The solid state luminescent property of 1 was also studied at room temperature.

关键词： crystal structure coordination polymer 3,5-dinitro-salicylic acid,

Classification of microseismic events in high stress zone

在线全文

学校读者我要写书评

暂无评论

Mining Science and Technology 2009年第6期19卷 718-723页

作者： CAO An-ye DOU Lin-ming YAN Ru-ling JIANG Heng LU Cai-ping DU Tao-tao LU zhen-yu State Key Laboratory for Coal Resource and Mine Safety China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China School of Mines China University of Mining ＆ Technology Xuzhou Jiangsu 221006 China

For the purpose of having a better understanding of failure mechanisms of rock fracturing in mines, the equivalent point source models of tensile, shear and explosive seismic events were established, and the relationship between far-field seismic displacements of the waves and the corresponding equivalent forces were analyzed as well. Based on the results of a microseismic monitoring carried out in the mining progress of 9202 working face under the upper remnant coal pillar in Sanhejian Mine, the waveform features of the seismic events associated with different failure modes were further analyzed. The results show that the signals corresponding to different failure mechanisms have different radiation patterns of the seismic displacements, and different characteristics in waveform features, such as dominant frequency, energy released, the ratio of S- to P-wave energy, and so on. In addition, the rock burst happened in the high stress zone is mainly the result of the strong shear fracturing in the mining process. The results of this study have significantly improved the understanding of the characteristics of the failures associated with underground mining, and will greatly benefit the prevention and control of rock burst hazards in burst-prone mines.

关键词： rock burst microseismic monitoring failure mechanism waveform characteristics

Prevalence of and risk factors for postprandial hypotension in older Chinese men

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2015年第6期12卷 600-604页

作者： Xiao ZOU Jian CAO Jian-Hua LI Yi-xin HU yu-Song GUO Quan-Jin SI Li FAN Geriatric Cardiology Department Chinese PLA General Hospital Beijing China Department of Health Care in Nanlou Chinese PLA General Hospital Beijing China Healthcare Department Hainan Branch of Chinese PLA General Hospital Sanya Hainan China

Objective To assess the prevalence of and risk factors for postprandial hypotension （PPH） among old and very old Chinese men. Methods The study included 349 Chinese men aged 65 and older, grouped into two age categories： group 1 （old） included 163 men aged 65 to 80 years; group 2 （very old） included 186 men aged over 80 years. Blood pressure changes after meals were assessed every 15 min by ambulatory blood pressure monitoring. Symptoms after meal ingestion and after standing up and changes in the baseline condition relative to blood pressure changes were observed continuously. Additional baseline data included body mass index, medical history, and medication use Results The prevalence of PPH was 59.3% overall and was significantly higher in group 2 than group 1 （63.4% vs. 54.6%, P 〈 0.05）. In group 2, the prevalence of PPH after breakfast （33.8%） and lunch （32.1%） were higher than that after supper （20.9%）, P 〈 0.05. Hypertension and age were significant risk factors for PPH （OR = 2.188, 95% CI： 1.134-4.223, P = 0.02; OR = 1.86, 95% CI： 1.112-3.11, P = 0.018, respectively）. In contrast, acarbose use was protective against PPH （OR = 0.4, 95% CI： 0.189-0.847, P = 0.017）. The decrease in blood pres- sure during PPH was 20-40 mmHg and the maximum was 90 mmHg. PPH usually occurred at 30-60 min after a meal and lasted 30-120 rnin. Conclusions These findings demonstrate that the prevalence of PPH in men aged over 80 years is significantly higher than those in men aged 65 to 80 years, and the blood pressure decline is also higher for men aged over 80 years. In addition, hypertension and age were main risk factors for PPH in the older men, which suggest that preventing and treating PPH is worthwhile.

关键词： Male Postprandial hypotension Prevalence The elderly

Influence of Basicity on the Formation of Cluster Ions/Adduct Ions for Organic Ammonium Halides by Positive Secondary Ion Mass Spectrometry

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 1997年第4期13卷 93-97页

作者： FU Hua CHEN xin LI Zhao long ZHAO yu fen WANG Jing zun XIAO Hong zhan WU Yi Bioorganic Phosphorus Chemistry Laboratory Department of ChemistryTsinghua UniversityBeijing100084 Beijing Institute of Microchemistry Beijing100091

ＩｎｆｌｕｅｎｃｅｏｆＢａｓｉｃｉｔｙｏｎｔｈｅＦｏｒｍａｔｉｏｎｏｆＣｌｕｓｔｅｒＩｏｎｓ／ＡｄｄｕｃｔＩｏｎｓｆｏｒＯｒｇａｎｉｃＡｍｍｏｎｉｕｍＨａｌｉｄｅｓｂｙＰｏｓｉｔｉｖｅＳｅｃｏｎｄａｒｙＩｏｎＭａｓＳ... 详细信息

ＩｎｆｌｕｅｎｃｅｏｆＢａｓｉｃｉｔｙｏｎｔｈｅＦｏｒｍａｔｉｏｎｏｆＣｌｕｓｔｅｒＩｏｎｓ／ＡｄｄｕｃｔＩｏｎｓｆｏｒＯｒｇａｎｉｃＡｍｍｏｎｉｕｍＨａｌｉｄｅｓｂｙＰｏｓｉｔｉｖｅＳｅｃｏｎｄａｒｙＩｏｎＭａｓＳｐｅｃｔｒｏｍｅｔｒｙＦＵＨｕａ，...

关键词： Positive secondary ion mass spectrometry(PSIMS) Organic ammonium halide Basicity Cluster ion /Adduct ion

STRUCTURE ASSIGNMENT FOR EPIMERIC THYMIDINE-3'-YL BENZOIN PHOSPHATES

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1995年第7期6卷 577-580页

作者： xin CHEN, yu Ping FENG, Nan Jing ZHANG, yu Fen ZHAO (Bio-organic Phosphorus Chemistry Laboratory, Department of Chemistry Tsinghua University, Beijing 100084) Tsing Hua Univ Dept Chem Bioorgan Phosphorus Chem Lab Beijing 100084 Peoples R China

Reaction of Oxyphosphorane (1) with thvmidine (2) followed .by hydrolysis under mild conditions afforded TMP, TpT and thymidine-3'-yl benzoin phosphates(3). The structures of 3 were determined by 31P, 1H. 13C,NMR and mass spectral data. and 31P-1H COSY experiments. The possible formation mechanism of 3 was also discussed.

关键词：

Remolding Diversified Objects in Ada95: Toward A Object Pattern

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2001年第Z1期6卷 247-255页

作者： Liang Xian zhong, Wang zhen yu Wuhan Digital Engineering Institute P. O. Box 74223, Wuhan 430074, China Wuhan Digital Engineering Institute Wuhan China

Ada provides full capacities of supporting object orientation, but the diversified objects patterned in Ada are so intricate that Ada95's aim would be demolished. In order to complement the disfigurement that Ada does lack for a pristine notion of class, this paper presents a remolded object pattern known as A object, an Ada based class description language A ObjAda aiming at support for A object pattern and the related approach for key algorithms and implementation. In consequent, A ObjAda hereby promotes Ada with highlighted object orientation, which not only effectively exploits the capacities in Ada95, but also rationally hides befuddling concepts from Ada95.

关键词： ADT (abstract data type) ASM (abstract state machine) V object U object A object pattern

Advancements of Macrophages Involvement in Pathological Progression of Colitis-Associated Colorectal Cancer and Associated Pharmacological Interventions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第6期30卷 565-576页

作者： KE Jun-yu SONG Jin-bin LI Long HE zhen-fan HUANG Zhuo-jian LIU zheng-lin CHEN Gui-rong WANG Hai-yan WEN Su-ru ZHOU Heng-li MA Hui-lin DU Qun WU Yong-qiang LI Yan-wu CHEN xin-lin School of Basic Medical Sciences Guangzhou University of Chinese MedicineGuangzhou510006China Department of Surgery II Gaozhou Hospital of Traditional Chinese Medicine Affiliated to Guangzhou University of Chinese MedicineGaozhou525200China Science and Technology Innovation Center Guangzhou University of Chinese MedicineGuangzhou510405China The First Clinical Medical College of Guangzhou University of Traditional Chinese Medicine Guangzhou510405China

Intestinal macrophages play crucial roles in both intestinal inflammation and immune homeostasis. They can adopt two distinct phenotypes, primarily determined by environmental cues. These phenotypes encompass the classically activated pro-inflammatory M1 phenotype, as well as the alternatively activated anti-inflammatory M2 phenotype. In regular conditions, intestinal macrophages serve to shield the gut from inflammatory harm. However, when a combination of genetic and environmental elements influences the polarization of these macrophages, it can result in an M1/M2 macrophage activation imbalance, subsequently leading to a loss of control over intestinal inflammation. This shift transforms normal inflammatory responses into pathological damage within the intestines. In patients with ulcerative colitis-associated colorectal cancer (UC-CRC), disorders related to intestinal inflammation are closely correlated with an imbalance in the polarization of intestinal M1/M2 macrophages. Therefore, reinstating the equilibrium in M1/M2 macrophage polarization could potentially serve as an effective approach to the prevention and treatment of UC-CRC. This paper aims to scrutinize the clinical evidence regarding Chinese medicine (CM) in the treatment of UC-CRC, the pivotal role of macrophage polarization in UC-CRC pathogenesis, and the potential mechanisms through which CM regulates macrophage polarization to address UC-CRC. Our objective is to offer fresh perspectives for clinical application, fundamental research, and pharmaceutical advancement in UC-CRC.

关键词： macrophage ulcerative colitis colon cancer Chinese medicine