检索结果-南通市图书馆

characterizing the rock geological time by terahertz spectrum

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2019年第1期62卷 95-98页

作者： WenXiu Leng QingYan Li RiMa Bao Kun Zhao XinYang Miao YiZhang Li Beijing Key Laboratory of Optical Detection Technology for Oil and Gas China University of Petroleum State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum

In the field of geology,it is necessary to get the information about the rock geological time,which includes absolute geologic age and relative geologic age .Tracing the evolutionary history of the earth is one of the research tasks of earth science.Time,space,material and motivation are the basic elements for studying geological processes and enviromnental evolution,and time is the basis for studying geological problems.A clear understanding of the interaction between the above elements will be able to clearly make sure the evolution of the earth and the conditions of rock formation.Nowadays,it is urgent to get the geochronological data of rocks for wide range comparison,so as to study the evolution trend and development rule of the earth's crust .

关键词： characterizing geology understanding

Three characterizing numbers of partition logics

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1995年第20期40卷 1673-1676页

作者：沈恩绍 Department of Computer Science Shanghai Jiaotong University Shanghai 200030 China

Partition logics are a family of newly proposed extended logics. They possess quite strong expressibility as well as rather good model-theoretic features. The introducing background of partition quantifiers is mathematical; however, they have found themselves in applications to computer science. In the following we shall further study the framework of model-theoretic logics, some foundamental properties, such as the well-ordering number,Hanf number and Lwenheim number, of their representatives: L(P1.1) and L(Q1.1).

关键词： model-theoretic logic partition logic characterizing numbers.

Modeling and characterizing the typical under-ice acoustic channel for the Arctic

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Acoustics 2019年第2期38卷 167-177页

作者： ZHU Guangping YIN Jingwei ZHOU Huanling CHEN Wenjian HU Siwei GUO Longxiang Acoustic Science and Technology Laboratory Harbin Engineering University College of Underwater Acoustic Engineering Harbin Engineering University

The properties of arctic underwater acoustic channel were researched using BurkeTwersky(BT) model and ray theory.In the BT model,sea ice ridge is assumed as a set of semi-elliptical cylinder randomly distributed on a stress-free surface.By approximation of low frequency and high frequency of the BT model,the reflection coefficients were calculated at different frequencies.On the basis of ray theory,the acoustic field was calculated and the properties of underwater acoustic channel was analyzed.Compared to underwater acoustic channel properties when the boundary is air,the results show that under the ice surface some sound rays disappear during transmission,because the ice surface reflection coefficients is less than absolute soft surface.Especially,the higher the frequency,the higher the under-ice transmission loss.As a result,under-ice condition is unfavourable for acoustic signals to travel far.Besides,as to the channel structure,the reflection coefficient of ice layer is smaller,the channel multi-path structure is not significant compared to water-air interface without ice.The research results are valuable for our understanding of hydroacoustic channel and the prediction of the sonar system working in the polar region.

关键词： Modeling and characterizing the typical under-ice acoustic channel for the Arctic

Differential molecular profiles and associated functionalities characterize connective tissue grafts obtained at different locations and depths in the human palate

在线全文

学校读者我要写书评

暂无评论

International Journal of Oral Science 2023年第4期15卷 701-717页

作者： Maria B.Asparuhova Xiaoqing Song Dominic Riedwyl Geert van Geest Dieter D.Bosshardt Anton Sculean Laboratory of Oral Cell Biology School of Dental MedicineUniversity of BernBernSwitzerland Department of Periodontology School of Dental MedicineUniversity of BernBernSwitzerland Interfaculty Bioinformatics Unit University of BernBernSwitzerland Robert K.Schenk Laboratory of Oral Histology School of Dental MedicineUniversity of BernBernSwitzerland

The present study aimed to assess the molecular profiles of subepithelial connective tissue grafts(CTGs)obtained at different locations and depths in the human palate.Sixty-four CTGs belonging to anterior deep(AD),anterior superficial(AS),posterior deep(PD),and posterior superficial(PS)groups were subjected to RNA-Sequencing and their transcriptomes were analyzed computationally.Functional correlations characterizing the CTG groups were validated by cell biological experiments using primary human palatal fibroblasts(HPFs)extracted from the CTGs.A clearly more pronounced location-dependent than depth-dependent difference between the grafts,with a minimal number of genes(4)showing no dependence on the location,was revealed.Epithelial,endothelial,and monocytic cell migration was strongly(P<0.001)potentiated by AD-and PS-HPFs.Moreover,significantly increased expression of genes encoding C-C and C-X-C motif chemokine ligands as well as significantly(P<0.01)activated p38 signaling suggested immunomodulatory phenotype for AD-and PS-HPFs.Increased growth factor gene expression and significantly activated(P<0.001)Erk and Akt signaling in HPFs originating from A-CTGs implied their involvement in cell survival,proliferation,and motility.Prominent collagen-rich expression profile contributing to high mechanical stability,increased osteogenesis-related gene expression,and strongly activated(P<0.001)Smad1/5/8 signaling characterized HPFs originating from P-CTGs.The present data indicate that in humans,differences between palatal CTGs harvested from different locations and depths appear to be location-rather than depth-dependent.Our findings provide the basis for future personalization of the therapeutic strategy by selecting an optimal graft type depending on the clinical indications.

关键词： selecting characterizing showing

A novel vector of topological and structural information for amino acids and its QSAR applications for peptides and analogues

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2008年第10期51卷 946-957,1021-1056页

作者： LI ZhiLiang LI GenRong SHU Mao SUN JiaYing YANG ShanBin MEI Hu ZHANG MengJun ZHOU Ping WU ShiRong CHEN GuoHua LU FengLin LU TingTing College of Chemistry and Chemical Engineering/College of Bioengineering Chongqing UniversityChongqing 400044China State Key Laboratory of Chemo/Biosensing and Chemometrics Hunan UniversiryChangsha410082China College of Medical Laboratory Third Military Medical UniversityChongqing400038China Life Sciences Technology Centre Singapore Polytechnic500 Dover RoadSingapore 139651Singapore

A new descriptor, called vector of topological and structural information for coded and noncoded amino acids (VTSA), was derived by principal component analysis (PCA) from a matrix of 66 topological and structural variables of 134 amino acids. The VTSA vector was then applied into two sets of peptide quantitative structure-activity relationships or quantitative sequence-activity modelings (QSARs/ QSAMs). Molded by genetic partial least squares (GPLS), support vector machine (SVM), and immune neural network (INN), good results were obtained. For the datasets of 58 angiotensin converting en-zyme inhibitors (ACEI) and 89 elastase substrate catalyzed kinetics (ESCK) , the R2, cross-validation R2, and root mean square error of estimation (RMSEE) were as follows: ACEI, R2cu≥0.82, Q2cu≥0.77, Ermse≤0.44 (GPLS+SVM); ESCK, R2cu≥0.84, Q2cu≥0.82, Ermse≤0.20 (GPLS+INN), respectively.

关键词： vector of topological and structural information for coded and noncoded amino acids (VTSA) peptide quantitative structure activity relationship (pQSAR) molecular structural characterizing descriptors (MSCD) quantitative sequence activity modelings (QSAMs) angiotensin converting enzyme inhibitors (ACEI) elastase substrate catalyzed kinetics (ESCK)

COMPARISON OF GPC AND THERMAL FIELDFLOW FRACTIONATION METHODS FOR LINEAR AND STAR BRANCHED POLYSTYRENE SAMPLES

在线全文

学校读者我要写书评

暂无评论

高分子科学(英文版) 1985年第3期3卷 265-271页

作者：高玉书汪健沈家(马总) Institute of Chemistry Academia Sinica Beijing Department of Chemistry Jilin University Changchun Changchun

The Thermal Field-Flow Fractionation (TFFF) method was used to determine the elution volumeof a series of star branched polystyrene having different number of arms but the same arm molecularweigh and polystyrene standards with narrow distribution whose molecular weight ranged from5.0×10~4 to 8.6×10~5. Results were obtained by measuring at two temperature difference (△T=30℃and △T=50℃in THF. The same star branched samples were measured by means of GPC method.Comparison of Vr-Mrelationships obtained from TFFF and GPC showed that the displacement of V_r-M curves for star and linear polystyrene is larger than that in GPC. This difference is caused by theentirely different mechanism of separation for these two methods. As the controlling factor is hy-drodynamic volume of the polymer chain in solution for GPC, it is the diffusion coefficient of polymermolecules for TFFF. The experimental results indicate that the influence of variance of chain struc-ture on diffusion coefficient is stronger than that on the hydrodynamic volume and that TFFF tech-nique may be used as a method for characterizing branching of polymer molecules. For this pur-pose a proper theoretical model and more accurate experiments are needed.

关键词： polystyrene struc branching branched narrow hydrodynamic solute retention ranged characterizing

Remarks on Hao Wang's Conceptualism and Predicativism

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

哲学门 2004年第S1期5卷 131-140页

作者： Xing Taotao Department of Philosophy Peking University

Part One In his later works on the philosophy of mathematics,Hao Wang proposes a general form of Platonism.He states that the first step to characterizing mathematics is naturally to see it as a part of our shared con... 详细信息

关键词： scheme. characterizing states

Physical Constants as Result of the Many Hypercubic Lattices of a Multidirectional Discrete Space

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 Modern Physics 2020年第3期11卷 432-447页

作者： Christiaan T. de Groot Retired University of Applied Sciences Utrecht Netherlands

A multidirectional discrete space consists of numerous hypercubic lattices each of which contains one of the spatial directions. In such a space, several groups of lattices can be distinguished with a certain property. Each group is determined by the number of lattices it comprises, forming the characterizing numbers of the space. Using the specific properties of a multidirectional discrete space, it is shown that some of the characterizing numbers can be associated with a physical constant. The fine structure constant appears to be equal to the ratio of two of these numbers, which offers the possibility of calculating the series of smallest numerical values of these numbers. With these values, a reasoned estimate can be made of the upper limit of the smallest distance of the discrete space of approximately the Planck length.

关键词： Hypercubic Lattice Multidirectional Discrete Space characterizing Numbers Fine Structure Constant Physical Constants Planck Length

Preliminary Research on the Dynamics of Resetting Complex System by Using the Time Series

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

Earthquake Research in China 1994年第4期8卷 88-92页

作者： Lu Yuanzhong,Zheng Zhaobi and Xu DaohaiInstitute of Crustal Dynamics,SSB,Beijing 100085,China Seismologicai Bureau of Annul Province,Hefei 230031,China

The dynamics of resetting the complex system by using time series data is one of the most fascinating subjects in nonlinear science.At present,scientists have a way of directly presenting the deterministic law produced by a number of phenomena in the natural world or the differential equation to describe those phenomena,but can obtain a large amount of observed data with time.If the research on the dynamical characteristics of these complex phenomena is based on time series,it will obviously have practical significance for revealing the essence of things.To reset the dynamics of the seismic complex system by using seismic time series and then to analyze,seek the deterministic law characterizing the seismic process,to recognize the dynamical behavior of the seismic process and to make in-depth research on earthquake prediction have become urgent research goals.

关键词： deterministic dynamical fascinating essence urgent recognize revealing characterizing saturated chaos