检索结果-南通市图书馆

Effect of MR field strength on the Texture Features of Cerebral T2-FLAIR Images: A Pilot Study

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Sciences Journal 2020年第3期35卷 248-253页

作者： Xuedan Wang Shiwei Wang Botao Wang Zhiye Chen Department of Radiology Hainan Hospital of Chinese PLA General HospitalSanyaHainan 572013China

Objective To investigate effect of MR field strength on texture features of cerebral T2 fluid attenuated inversion recovery(T2-FLAIR)*** We acquired cerebral 3 D T2-FLAIR images of thirty patients who were diagnosed with ischemic white matter lesion(WML)with MR-1.5 T and MR-3.0 T *** texture features which included mean signal intensity(Mean),Skewness and Kurtosis,and gray level co-occurrence matrix(GLCM)texture features which included angular second moment(ASM),Contrast,Correlation,Inverse difference moment(IDM)and Entropy,of regions of interest located in the area of WML and normal white matter(NWM)were measured by ImageJ *** texture parameters acquired with MR-1.5 T scanning were compared with MR-3.0 T *** The Mean of both WML and NWM obtained with MR-1.5 T scanning was significantly lower than that acquired with MR-3.0 T(P0.05).ASM,Correlation and IDM of both WML and NWM acquired with MR-1.5 T revealed significantly lower values than those with MR-3.0 T(Pfield strength showed no significant effect on histogram textures,while had significant effect on GLCM texture features of cerebral T2-FLAIR images,which indicated that it should be cautious to explain the texture results acquired based on the different MR field strength.

关键词： magnetic resonance imaging field strength fluid attenuated inversion recovery white matter texture features

Investigation of the Value of Different field strength MRI Scans for the Diagnosis of Rotator Cuff in Juries

在线全文

学校读者我要写书评

暂无评论

Open Journal of Radiology 2022年第1期12卷 32-36页

作者： Xiao Li Wenda Shi Fan Xu Qingshan Li Xu Xiao Departments of Radiology Affiliated Hospital of Chengde Medical College Chengde China Departments of Oncology Affiliated Hospital of Chengde Medical College Chengde China Departments of Pharmacy Affiliated Hospital of Chengde Medical College Chengde China

Objective: A comparison of the difference between the two types of field MR scan in diagnosis of shoulder joint injury. Method: Randomly selected 153 patients with arthroscopic or open arthroplasty who had shoulder pain or dysfunction treated in our hospital from 2014 to 2017 were divided into 1.5 T group and 3.0 according to the field strength of MRI examination. Postoperative pathology was a gold standard. The sensitivity, specificity, consistency, and predictive value of two field-strength MRI examinations in the diagnosis of rotator cuff tears were calculated and compared. Results: The sensitivity, specificity, crude consistency, positive predictive value, and negative predictive value of the 1.5 T group were 68.75%, 82.35%, 73.47%, 88.00%, and 58.33%, respectively. The 3.0 T group was 72.22%, 89.47%, 78.18%, 92.86% and 62.96%, the differences between the above indicators were not statistically significant (P > 0.05). Conclusion: There was no difference in the authenticity and benefit index of rotator cuff injury diagnosed by 1.5 T and 3.0 T MRI.

关键词： Shoulder Joint Magnetic Resonance Imaging field strength Diagnostic Value

Tuning the strength of built-in electric field in 2D/2D g-C_(3)N_(4)/MS_(2) and g-C_(3)N_(4)/ZrS_(2) S-scheme heterojunctions by nonmetal doping

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 Materiomics 2021年第5期7卷 988-997页

作者： Bicheng Zhu Haiyan Tan Jiajie Fan Bei Cheng Jiaguo Yu Wingkei Ho State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology122 Luoshi RoadWuhan430070China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China Department of Science and Environmental Studies The Education University of Hong KongTai PoN.T.Hong Kong999077China

Single photocatalysts usually exhibit unsatisfactory performance due to the serious recombination of photogenerated electron‒hole *** two photocatalysts to construct S-scheme heterojunction could solve this *** S-scheme mechanism,the interfacial built-in electric field(IEF)provides a vital driving force for efficient charge *** the IEF is a feasible strategy to further improve the photocatalytic ***,a novel idea of tuning the strength of IEF in 2D/2D graphitic carbon nitride(g-C_(3)N_(4))/MS2(M=Sn,Zr)S-scheme heterojunctions by nonmetal doping was developed by employing density functional theory *** nonmetal elements(O,P,and S)were severally introduced into g-C_(3)N_(4)/MS_(2) *** density difference suggested that O and S doping led to increased interfacial electron transfer,while P doping had minimal *** expected,the calculated field strength of O-and S-doped g-C_(3)N_(4)/MS_(2) composites was significantly larger than that of pristine and P-doped g-C_(3)N_(4)/MS_(2) ***,O and S doping endowed g-C_(3)N_(4)/MS_(2) Sscheme heterojunctions with enhanced IEF and more thorough charge ***,the experimentally synthesized O-C_(3)N_(4)/ZrS_(2) composite exhibited better photocatalytic H2-production activity than g-C_(3)N_(4)/ZrS_(2) *** work proposed an original idea of employing proper nonmetal doping to magnify the advantage of S-scheme heterojunction in accelerating charge separation.

关键词： Graphitic carbon nitride Density functional theory field strength Photocatalysis Van der Waals heterostructure

Interactions of Heavy Metal Ions with Paddy Soils as Inferred from Wien Effect Measurements in Dilute Suspensions

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

Pedosphere 2006年第6期16卷 718-725页

作者： JIANG Jun LI Cheng-Bao ZHAO An-Zhen XU Ren-Kou WANG Yu-Jun S. P. FRIEDMAN Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China Institute of Soil Water and Environmental Sciences Agricultural Research Organization Voleani Center Bet Dagan 50250 Israel

Interactions of three heavy metal ions, Cu^2＋, Cd^2＋, and Pb^2＋, and, for comparison, Na^＋ with electrodialytic clay fractions （less than 2μm in diameter） of four paddy soils as well as a yellow-brown soil as a control soil were evaluated based on measurements of the Wien effect in dilute suspensions with a clay concentration of 10 g kg^-1 in four nitrate solutions of 2 × 10^-4/z mol L^-1, where z is the cation valence, and a nitric acid solution of 3 × 10^-5 mol L^-1, field strengths ranging from 15 to 230 kV cm^-1 were applied for measuring the electrical conductivities （ECs） of the suspensions. The mean free binding energies between the various cations and all of the soils determined from exchange equilibrium increased in the order： Na^＋〈 Cd^2＋〈 Cu^2＋〈 Pb^2＋. In general, the ECs of the suspensions in the sodium nitrate solution were smaller than those of the suspensions in the heavy metal solutions because of the lower electrophoretic mobility of sodium compared to the divalent cations. In terms of relative electrical conductivity-field strength relationships, relative electrical conductivity （REC） of suspensions containing various cations at field strengths larger than about 50 kV cm^-1 were in the descending order： Na^＋〉 Cu^2＋〉 Cd^2＋〉 Pb^2＋ for all tested soils. A characteristic parameter of the REC-field strength curves, AREC200, REC at a field strength of 200 kV cm^-1 minus that at the local minimum of the concave segment of the REC-field strength curves, characterized the strength of adsorption of the cations stripped off by the applied strong electrical field, and for all soils the values of AREC200 were generally in the order： Na^＋〈 Cu^2＋ ≤ Cd^2＋〈 Pb^2＋.

关键词： binding energy electrical conductivity field strength heavy metal ions paddy soils

Wien Effect Characterization of Interactions Between Ions and Charged Sites on Clay Surfaces of Variable-Charge Soils

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2009年第5期19卷 545-553页

作者： ZHU Hao-Wen WANG Yu-Jun ZHOU Jun JIANG Jun LI Cheng-Bao ZHOU Dong-Mei S. P. FRIEDMAN Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 (China) Institute of Soil Water and Environmental Sciences Agricultural Research Organization the Volcani Center Bet Dagan 50250 (Israel)

To investigate the interactions of oppositely charged sites on the surfaces of variable-charge soil particles with cations and anions, and to evaluate the mean Gibbs free binding and adsorption energies of various cations on particles of red soil and latosol, clay fractions smaller than 2 μm were separated from samples of the two variable-charge soils. Ferric oxides were removed from part of the clay fractions, which were then saturated with various chlorides （NaC1, KCl, CaCl2, CdCl2 or LaCl3）. Electrical conductivities （EC） of dilute suspensions of the original and of the iron oxides-free clay fractions in deionized water were measured with the SHP-2 short high-voltage pulse apparatus, which enables measurement of the Wien effect at field strengths （E） from 14 to 250 kV cm^-1. The Wien effect （EC-E） curves revealed EC increases of red soil suspensions between 14 and 200 kV cm^-1, of 8.3, 8.4, 12.1, 5.9, and 1.2 μS cm^-1 for NaCl, KCl, CaCl2, CdCl2, and LaCl3, respectively, reflecting the differing interactions with the various cations and chloride. The EC increments with the iron-free red soil suspensions were higher, being 29.7, 17.2, and 15.3 μS cm^-1 for NaCl, CaCl2, and CdCl2, respectively. In the natural latosol suspensions the EC increments were practically zero, whereas in the iron-free fractions there were significant EC increments of 10.3, 5.7, 5.0, and 1.6μS cm^-1 for NaCl, CaCl2, CdCl2, and LaCl3, respectively.

关键词： electrical conductivity field strength iron oxide overlapping ζ potential

Investigation into Effects of Buildings near Broadcasting Antenna on Far fields Using a Finite-Difference Method

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 1998年第2期2卷 55-59页

作者： Zhang Yongling Kong Fanli Wang Zheng School of Communication and Information Engineering Shanghai Broadcast Film and Television Bureau

A steady state finite difference method is used to calculate EM fields generated by an MW broadcasting antenna. The effects of buildings on the wave propagation is studied based on the numerical results and field measurements. Both the algorithm and results are useful in the design of broadcasting antennas, as well as in the selection of transmitting sites.

关键词： finite difference method antenna field strength