检索结果-南通市图书馆

Composition and distribution of NSO compounds in two different shales at the early maturity stage characterized by negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2018年第2期15卷 289-296页

作者： chang-Wei ke Yao-Hui Xu xiang-Chun chang Wei-Bin Liu key Laboratory of Exploration Technologies for Oil and Gas Resources (Yangtze University) Ministry of Education College of Resources and Environment Yangtze University College of Earth Science and Engineering Shandong University of Science and Technology Oil and Gas Survey China Geological Survey

Gas chromatography/mass spectrometry （GC/MS） can only analyze volatile molecular compounds, and it has limitations when applied to determine the complex components of crude oils and hydrocarbon source rocks. Based on Fourier transform ion cyclotron resonance mass spectrometry （FT-ICR-MS） and GC/MS analyses, the molecular compositions of NSO compounds in extracts from the Permian Dalong Formation, Sichuan Basin and the Permian Lucaogou Formation, Junggar Basin in China were compared. Analyses of types of heteroatoms present （S~, $2, $3, OS, OS2, 02S, NS, and NOS compounds） suggest that marine shales from the Dalong Formation are mainly composed of carboxylic acids （02 com- pounds） with a high abundance of fatty acids, indicating a marine phytoplankton organic source. However, lacustrine shales from the Lucaogou Formation are dominated by pyrrolic compounds （N1 compounds） with abundant dibenzocar- bazole. It suggests that the organic source materials may be derived from lower aquatic organisms and lacustrine algae. Overall, FT-ICR-MS has potential for applications in analyses and determination of depositional environments and organic sources in petroleum geology.

关键词： Fourier transform ion cyclotron resonance mass spectrometry Dalong Formation Lucaogou Formation NSO compounds Sedimentary environment

High Order Deep Neural Network for Solving High Frequency Partial Differential Equations

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2022年第2期31卷 370-397页

作者： Zhipeng chang ke Li Xiufen Zou Xueshuang xiang Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100875P.R.China School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China Information Engineering University Zhengzhou 450001P.R.China

This paper proposes a high order deep neural network(HOrderDNN)for solving high frequency partial differential equations(PDEs),which incorporates the idea of“high order”from finite element methods(FEMs)into commonly-used deep neural networks(DNNs)to obtain greater approximation *** main idea of HOrderDNN is introducing a nonlinear transformation layer between the input layer and the first hidden layer to form a high order polynomial space with the degree not exceeding p,followed by a normal *** order p can be guided by the regularity of solutions of *** performance of HOrderDNNis evaluated on high frequency function fitting problems and high frequency Poisson and Helmholtz *** results demonstrate that:HOrderDNNs(p>1)can efficiently capture the high frequency information in target functions;and when compared to physics-informed neural network(PINN),HOrderDNNs(p>1)converge faster and achieve much smaller relative errors with same number of trainable *** particular,when solving the high frequency Helmholtz equation in Section 3.5,the relative error of PINN stays around 1 with its depth and width increase,while the relative error can be reduced to around 0.02 as p increases(see Table 5).

关键词： Deep neural network high order methods high frequency PDEs

High Order Deep Domain Decomposition Method for Solving High Frequency Interface Problems

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

Advances in Applied Mathematics and Mechanics 2023年第6期15卷 1602-1630页

作者： Zhipeng chang ke Li Xiufen Zou Xueshuang xiang School of Mathematics and Statistics Wuhan UniversityWuhanHubei 430072China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100875China Information Engineering University ZhengzhouHenan 450001China

This paper proposes a high order deep domain decomposition method(HOrderDeepDDM)for solving high-frequency interface problems,which combines high order deep neural network(HOrderDNN)with domain decomposition method(DDM).The main idea of HOrderDeepDDM is to divide the computational domain into some sub-domains by DDM,and apply HOrderDNNs to solve the high-frequency problem on each ***,we consider an adaptive learning rate annealing method to balance the errors inside the sub-domains,on the interface and the boundary during the optimization *** performance of HOrderDeepDDM is evaluated on high-frequency elliptic and Helmholtz interface *** results indicate that:HOrderDeepDDM inherits the ability of DeepDDM to handle discontinuous interface problems and the power of HOrderDNN to approximate high-frequency *** detail,HOrderDeepDDMs(p>1)could capture the high-frequency information very *** compared to the deep domain decomposition method(DeepDDM),HOrderDeepDDMs(p>1)converge faster and achieve much smaller relative errors with the same number of trainable *** example,when solving the high-frequency interface elliptic problems in Section 3.3.1,the minimum relative errors obtained by HOrderDeepDDMs(p=9)are one order of magnitude smaller than that obtained by DeepDDMs when the number of the parameters keeps the same,as shown in Fig.4.

关键词： Deep neural network high order methods high-frequency interface problems do-main decomposition method

On the Error Linear Complexity Spectrum of Binary Sequences with Period of Power of Two

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 Journal of Electronics 2015年第2期24卷 366-372页

作者： chang Zuling ke Pinhui School of Mathematics and Statistics Zhengzhou University Fujian Provincial key Laboratory of Network Security and Cryptology Fujian Normal University

The properties of error linear complexity of binary sequences with period of power of two are studied in this paper. Using the Games-Chan algorithm as main tool, accurate formulas of the minimum value k for which the k-error linear complexity is strictly less than the first and second critical error linear complexity are provided respectively.

关键词： Binary sequences Games-Chan algorithm Error linear complexity Spectrum

Methylprednisolone microsphere sustained-release membrane inhibits scar formation at the site of peripheral nerve lesion

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2016年第5期11卷 835-841页

作者： Qiang Li Teng Li xiang-chang Cao De-qing Luo ke-jian Lian The Affiliated Dongnan Hospital of Xiamen University Zhangzhou Fujian Province China

Corticosteroids are widely used for the treatment of acute central nervous system injury. However, their bioactivity is limited by their short half-life. Sustained release of glucocorticoids can prolong their efficacy and inhibit scar formation at the site of nerve injury. In the present study, we wrapped the anastomotic ends of the rat sciatic nerve with a methylprednisolone sustained-release membrane. Compared with methylprednisone alone or methylprednisone microspheres, the methylprednisolone microsphere sustained-release membrane reduced tissue adhesion and inhibited scar tissue formation at the site of anastomosis. It also increased sciatic nerve function index and the thickness of the myelin sheath. Our findings show that the methylprednisolone microsphere sustained-release membrane effectively inhibits scar formation at the site of anastomosis of the peripheral nerve, thereby promoting nerve regeneration.

关键词： nerve regeneration peripheral nerve injury nanometer scar methylprenisolone sustained-release membrane biological agents peripheral nerve neural regeneration

Structural and Optical Properties of ZnO Films with Different Thicknesses Grown on Sapphire by MOCVD

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第5期22卷 552-555页

作者： HOU chang-min HUANG ke-ke GAO Zhong-min LI xiang-shan FENG Shou-hua ZHANG Yuan-tao DU Guo-tong State key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China College of Electronic Science and Engineering Jilin University Changchun 130012 P. R. China

ZnO（002） films with different thicknesses, grown on Al2O3 （006） substrates by metal-organic chemical vapor deposition（ MOCVD）, were etched by Ar ion beams. The samples were examined by D8 X-ray diffraction, scanning electron microscopy（SEM）, and photoluminescence（PL） spectrometry. The structural properties vary with the increasing thickness of the films. When the film thickness is thin, the phi（Φ） scanning curves for ZnO（103） and sapphire（116） substrate show the existence of two kinds of orientation relationships between ZnO films and sapphire, which are ZnO（002）//Al2O3 （006）, ZnO（ 100）//Al2O3 （110） and ZnO（002）//Al2O3 （006）, ZnO（ 110）//Al2O3 （110）. When the thickness increases to 500 nm there is only one orientation relationship, which is ZnO（002）// Al2O3 （006）, ZnO [ 100]//Al2O3 [ 110]. Their photoluminescence（PL） spectra at room temperature show that the optical properties of ZnO films have been greatly improved when increasing the thickness of films is increased.

关键词： MOCVD ZnO film PL spectrum Thickness

Difference between type 2 gastroesophageal varices and isolated fundic varices in clinical profiles and portosystemic collaterals

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第17期10卷 5620-5633页

作者： Yu-Hu Song Hong-Yu xiang ke-ke Si Ze-Hui Wang Yu Zhang chang Liu ke-Shu Xu Xin Li Department of Gastroenterology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022Hubei ProvinceChina Department of Radiology Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022Hubei ProvinceChina Hubei Province key Laboratory of Molecular Imaging Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022Hubei ProvinceChina

BACKGROUND There is significant heterogeneity between gastroesophageal varices(GOV2)and isolated gastric varices(IGV1).The data on the difference between GOV2 and IGV1 are *** To determine the etiology,clinical profiles,endoscopic findings,imaging signs,portosystemic collaterals in patients with GOV2 and *** Medical records of 252 patients with gastric fundal varices were retrospectively collected,and computed tomography images were *** Significant differences in routine blood examination,Child-Pugh classification and MELD scores were found between GOV2 and *** incidence of peptic ulcers in patients with IGV1(26.55%)was higher than that of GOV2(11.01%),while portal hypertensive gastropathy was more commonly found in patients with GOV2(22.02%)than in those with IGV1(3.54%).Typical radiological signs of cirrhotic liver were more commonly observed in patients with GOV2 than in those with *** patients with GOV2,the main afferent vessels were via the left gastric vein(LGV)(97.94%)and short gastric vein(SGV)(39.18%).In patients with IGV1,the main afferent vessels were via the LGV(75.61%),SGV(63.41%)and posterior gastric vein(PGV)(43.90%).In IGV1 patients with pancreatic diseases,spleno-gastromental-superior mesenteric shunt(48.15%)was a major collateral *** patients with fundic varices,the sizes of gastric/esophageal varices were positively correlated with afferent vessels(LGVs and PGVs)and efferent vessels(gastrorenal shunts).The size of the esophageal varices was negatively correlated with gastrorenal shunts in GOV2 *** Significant heterogeneity in the etiology and vascular changes between GOV2 and IGV1 is useful in making therapeutic decisions.

关键词： Gastrorenal shunt Spleno-gastroomental-superior mesenteric shunt Liver cirrhosis Pancreatic diseases

Phase-field modeling of epitaxial growth with the Ehrlich-Schwoebel barrier: Model validation and application

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(Technological Sciences) 2015年第4期58卷 753-762页

作者： DONG xiang Lei XING Hui SHA Sha CHEN chang Le NIU Li Wei WANG Jian Yuan JIN ke Xin Shanxi key Laboratory for Condensed Matter Structure and Properties Department of Applied Physics Northwestern Polytechnical University

In this paper,we introduce different forms of mobility into a quantitative phase-field model to produce arbitrary Ehrlich-Schwoebel(ES)*** studies were carried out in the one-side step-flow model,which showed that the original mobility not only induces the ES effect,but also leads to larger numerical instability with increase of the step ***,another modified form of the ES barrier is proposed,and is found to be more suitable for large-scale *** applications were performed on the wedding-cake structure,coarsening and coalescence of islands and spiral *** results show that the ES barrier exhibits more significant kinetic effects at the larger deposition rates by limiting motions of atoms on upper steps,leading to aggregation on the top layers,as well as the roughening of growing surfaces.

关键词： epitaxial growth phase-field method Ehrlich-Schwoebel barrier kinetics interfacial

Photoluminescence Properties of Two-dimensional Planar Layer and Three-dimensional Island Layer for ZnO Films Grown Using MOCVD

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第6期22卷 692-695页

作者： HUANG ke-ke HOU chang-min GAO Zhong-min LI xiang-shan FENG Shou-hua ZHANG Yuan-tao ZHU Hui-chao DU Guo-tong State key Laboratory of Inorganic Synthesis and Preparative Chemistry Department of Electronic Science and Engineering Jilin University Changchun 130012 P. R. China

ZnO（002） films with different thicknesses ranging from 7 to 300 nm were grown on sapphire（006） substrates via metal-organic chemical vapor deposition （MOCVD）. The two-dimensional（2D） planar layer and the three-dimensional（3D） island layer were studied by using of X-ray diffraction（XRD） rocking curves and atomic force microscopy （AFM）. The room temperature photoluminescence （PL） spectra show a blue shift of the peak positions of the uhraviolet（UV） emission with increasing film thickness. The blue shift is remarkably high（393-380 nm） when an increase in film thickness（7-15 nm） is accompanied by the change of structure from a 2D planar layer to a 3D island layer. The PL spectra at 77 K also indicate that there are different transition mechanisms in the film thickness from a 2D planar layer to a 3D island layer near the 2D layer region.

关键词： ZnO films Metal-organic chemical vapor deposition(MOCVD) Photoluminescence Planar layer Island layer