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HISTORICAL DESERTIFICATION PROCESS IN HEXI CORRIDOR,CHINA

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Chinese Geographical Science 2005年第3期15卷 245-253页

作者： WANG Nai-ang zhang chun-hui LI gang CHENG Hong-yi College of Earth and Environment Sciences Lanzhou University Lanzhou 730000P. R. China

Over the last 2000 years, approximately 38 ancient cities were abandoned through desertification in Hexi Corridor, Northwest China. Among them, 21.05% were abandoned during the Northern and Southern Dynasties, 21.05% during the end of the Tang Dynasty and the Five Dynasties, and 57.9% during the Ming and Qing dynasties. At the same time, main lakes were shrinking rapidly from the 5th Century to the 6th Century and the end of the Qing Dynasty. The climate in these periods was relatively arid and cold with frequent dusts. The phase of these changes indicated that there were three periods of desertification enlargement in the northern China. They were Northern and Southern Dynasties, the end of Tang Dynasty and Five Dynasties, the Ming and Qing dynasties. The macro-process of desertification in the study area was controlled mainly by the climatic changes. But from the facts that the population density in the middle of Qing Dynasty had exceeded the critical index of population pressure in arid area and the usage rate of water resources had exceeded 40% in Hexi Corridor, this paper also suggests that human activities have played an important role in desertification processes of the study area mainly during the recent 300 years.

关键词： historical desertification climate change human activities Hexi Corridor

Effects of Shot Peening Process on Thermal Cycling Lifetime of TBCs Prepared by EB-PVD

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Chinese Journal of Aeronautics 2007年第2期20卷 145-147页

作者： ZHOU Zhao-hui GONG Sheng-kai LI He-fei XU Hui-bin zhang chun-gang WANG Lu School of Materials Science and Engineering Beij＇ing University of Aeronautics and Astronautics Beij＇ing 100083 China Shenyang Liming.4ero-Engine Group Corporation Shenyang 110043 China

Conventional two-layered thermal barrier coatings （TBCs） are prepared by electron beam physical vapor deposition （EB-PVD） with ZrO2-8 wt% Y2O3 （8YSZ） as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its surface roughness and the surface micro-hardness. A thermal cycling test at 1 273 Kx55 rain and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the parabolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide （TGO） responsible mainly for the failure of TBCs.

关键词： thermal cycling lifetime shot peening thermal barrier coatings (TBCs)

Biomechanical comparison of double-row versus transtendon single-row suture anchor technique for repair of the grade III partial articular-sided rotator cuff tears

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Chinese Medical Journal 2010年第21期123卷 3049-3054页

作者： zhang chun-gang ZHAO De-wei WANG Wei-ming REN Ming-fa LI Rui-xin YANG Sheng LIU Yu-peng Department of Orthopedics Affiliated Zhongshan Hospital of Dalian University Dalian Liaoning 116001 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian Liaoning 116001 China

Background For partial-thickness tears of the rotator cuff, double-row fixation and transtendon single-row fixation restore insertion site anatomy, with excellent results. We compared the biomechanical properties of double-row and transtendon single-row suture anchor techniques for repair of grade Ⅲ partial articular-sided rotator cuff *** In 10 matched pairs of fresh-frozen sheep shoulders, the infraspinatus tendon from 1 shoulder was repaired with a double-row suture anchor technique. This comprised placement of 2 medial anchors with horizontal mattress sutures at an angle of .≤45° into the medial margin of the infraspinatus footprint, just lateral to the articular surface, and 2 lateral anchors with horizontal mattress sutures. Standardized, 50% partial, articular-sided infraspinatus lesions were created in the contralateral shoulder. The infraspinatus tendon from the contralateral shoulder was repaired using two anchors with transtendon single-row mattress sutures. Each specimen underwent cyclic loading from 10 to 100 N for 50 cycles, followed by tensile testing to failure. Gap formation and strain over the footprint area were measured using a motion capture system; stiffness and failure load were determined from testing *** Gap formation for the transtendon single-row repair was significantly smaller （P 〈0.05） when compared with the double-row repair for the first cycle （（1.74±0.38） mm vs. （2.86±0.46） mm, respectively） and the last cycle （（3.77±0.45） mm vs. （5.89±0.61） mm, respectively）. The strain over the footprint area for the transtendon single-row repair was significantly smaller （P 〈0.05） when compared with the double-row repair. Also, it had a higher mean ultimate tensile load and *** For grade Ⅲ partial articular-sided rotator cuff tears, transtendon single-row fixation exhibited superior biomechanical properties when compared with double-row fixation.

关键词： biomechanics rotator cuff suture anchor

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蒙药文冠木配方颗粒指纹图谱及含量测定研究

中南药学 2024年第2期22卷 286-290页

作者：刘梦韩子璇杨立茹李佳程岚张纯刚辽宁中医药大学药学院辽宁大连116620 长治医学院药学系山西长治046000 祈蒙股份有限公司内蒙古赤峰024330

目的建立蒙药文冠木配方颗粒的高效液相色谱方法指纹图谱及指标成分的含量测定,为评价蒙药文冠木配方颗粒的质量提供参考。方法色谱柱:COSMOSIL 5C_(18)(4.6 mm×250 mm,5μm),柱温30℃,流动相采用乙腈-0.1%磷酸水溶液,流速1 mL·min^(-... 详细信息

目的建立蒙药文冠木配方颗粒的高效液相色谱方法指纹图谱及指标成分的含量测定,为评价蒙药文冠木配方颗粒的质量提供参考。方法色谱柱:COSMOSIL 5C_(18)(4.6 mm×250 mm,5μm),柱温30℃,流动相采用乙腈-0.1%磷酸水溶液,流速1 mL·min^(-1),梯度洗脱,检测波长270 nm,建立15批蒙药文冠木配方颗粒指纹图谱,同时对14种成分进行含量测定。结果建立了蒙药材文冠木配方颗粒的指纹图谱,相似度均大于0.900,共标定了21个共有峰,指认了其中14种成分,并对指认的成分进行含量测定。结论建立的指纹图谱及含量测定方法准确,稳定性好,可为蒙药材文冠木配方颗粒的质量控制提供参考。

关键词：蒙药文冠木指纹图谱含量测定聚类分析

Classification of knowledge graph completeness measurement techniques

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Journal of Systems Engineering and Electronics 2024年第1期35卷 154-162页

作者： zhang Ying XIAO gang Institute of Systems Engineering Academy of Military SciencesBeijing 100107China

At present,although knowledge graphs have been widely used in various fields such as recommendation systems,question and answer systems,and intelligent search,there are always quality problems such as knowledge omissions and *** assessment and control,as an important means to ensure the quality of knowledge,can make the applications based on knowledge graphs more complete and more accurate by reasonably assessing the knowledge graphs and fixing and improving the quality problems at the same ***,as an indispensable part of the knowledge graph construction process,the results of quality assessment and control determine the usefulness of the knowledge *** them,the assessment and enhancement of completeness,as an important part of the assessment and control phase,determine whether the knowledge graph can fully reflect objective phenomena and reveal potential connections among *** this paper,we review specific techniques of completeness assessment and classify completeness assessment techniques in terms of closed world assumptions,open world assumptions,and partial completeness *** purpose of this paper is to further promote the development of knowledge graph quality control and to lay the foundation for subsequent research on the completeness assessment of knowledge graphs by reviewing and classifying completeness assessment techniques.

关键词： quality assessment completeness assessment closed world assumptions open world assumption partial completeness assumption

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蒙药角茴香配方颗粒指纹图谱及含量测定研究

中南药学 2024年第2期22卷 291-295页

作者：韩子璇刘梦杨立茹李佳康廷国张纯刚辽宁中医药大学药学院辽宁大连116620 长治医学院药学系山西长治046000 祈蒙股份有限公司内蒙古赤峰024330

目的建立蒙药角茴香配方颗粒的HPLC指纹图谱及有效成分含量测定方法,为角茴香配方颗粒的质量控制提供参考。方法采用COSMOSIL 5 C_(18)(4.6 mm×250 mm,5μm)色谱柱,以乙腈-0.1 mol·L^(-)1乙酸铵(含0.05%冰醋酸)为流动相进行梯度洗脱,... 详细信息

目的建立蒙药角茴香配方颗粒的HPLC指纹图谱及有效成分含量测定方法,为角茴香配方颗粒的质量控制提供参考。方法采用COSMOSIL 5 C_(18)(4.6 mm×250 mm,5μm)色谱柱,以乙腈-0.1 mol·L^(-)1乙酸铵(含0.05%冰醋酸)为流动相进行梯度洗脱,流速为1.0 mL·min^(-1),柱温28℃,检测波长300 nm,进样量10μL,建立角茴香配方颗粒的指纹图谱,并对指认的3种化学成分进行含量测定。结果建立了角茴香配方颗粒的HPLC指纹图谱,标定了18个共有峰,指认芦丁、原阿片碱、黄连碱3种化学成分,15批角茴香配方颗粒相似度在0.982~1.000,芦丁、原阿片碱、黄连碱的含量分别为0.12%~0.23%、0.50%~0.54%、0.04%~0.05%。结论该方法稳定,准确,操作简单,重复性好,可为角茴香配方颗粒的评价及质量控制提供参考。

关键词：角茴香配方颗粒指纹图谱含量测定质量控制

Investigating the Absorption and Desorption Behavior of Methylene Chloride in the Poly(aryl ether ketone) Film with Different Crystallinities

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Chinese Journal of Polymer Science 2024年第2期42卷 239-246,I0009页

作者： Hong-Ru Yang Jin-Dong zhang Dong-Ting Gao gang Liu chun-Hai Chen Jia-Nan Yao Center for Advanced Low-Dimension Materials State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620China

Poly(aryl ether keton e)(PAEK) films with different crystallinities were obtained by controlling the cooling rate,which were subjected to the absorption and desorption of methylene chloride(CH_(2)Cl_(2)).We employed attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy analyses to investigate the diffusion behavior of CH_(2)Cl_(2) in PAEK films with different *** to the Fickian diffusion model,the calculated diffu sion coefficients of CH_(2)Cl_(2) in PAEK films were observed to decrease with increasing *** effect of CH_(2)Cl_(2)absorption and desorption on the mechanical properties of PAEK films with different crystallinity was further analyzed using tensile *** tensile tests exhibited that CH_(2)Cl_(2) has two concurrent effects:plasticization and solvent-induced *** scanning calorimetry(DSC) and wide-angle X-ray diffraction(WXRD) techniques further confirmed solvent-induced crystallization *** results would be beneficial to understand the solvent resistance of PAEK materials and consequently provide the practical application conditions of PAEK with a theoretical basis.

关键词： Poly(aryl ether ketone) Diffusion behavior Infrared spectra Solvent-induced crystallization Mechanical properties

Nanophononic metamaterials induced proximity effect in heat flux regulation

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Frontiers of physics 2024年第2期19卷 149-156页

作者： Jian zhang Haochun zhang gang zhang School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Institute of High Performance Computing Agency for ScienceTechnology and Research(A*STAR)Singapore 138632Singapore

Recent studies have shown that the construction of nanophononic metamaterials can reduce thermal conductivity without affecting electrical properties,making them promising in many fields of application,such as energy conversion and thermal ***,although extensive studies have been carried out on thermal conductivity reduction in nanophononic metamaterials,the local heat flux characteristic is still *** this work,we construct a heat flux regulator which includes a silicon nanofilm with silicon *** regulator has remarkable heat flux regulation ability,and various impacts on the regulation ability are ***,even in the region without nanopillars,the local heat current is still lower than that in pristine silicon nanofilms,reduced by the neighboring nanopillars through the thermal proximity *** combine the analysis of the phonon participation ratio with the intensity of localized phonon modes to provide a clear *** findings not only provide insights into the mechanisms of heat flux regulation by nanophononic metamaterials,but also will open up new research directions to control local heat flux for a broad range of applications,including heat management,thermoelectric energy conversion,thermal cloak,and thermal concentrator.

关键词： nanophononic metamaterials proximity effect

A high-performance lithium anode based on N-doped composite graphene

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Rare Metals 2024年第3期43卷 1030-1036页

作者： Can Jiao Hao-Bo Sun Li zhang Shang-Qian Zhao Guo-Yao Pang chun-Rong Zhao Shi-gang Lu General Research Institute for Nonferrous Metals Beijing100088China China Automotive Battery Research Institute Co.Ltd Beijing101407China

Lithium(Li)metal is the most promising electrode for next-gene ration rechargeable *** order to push the commercialization of the lithium metal batteries,a kind of nitrogen(N)-doped composite graphene(NCG)adopted as the Li plating host was prepared to regulate Li metal nucleation and suppress dendrite ***,a new kind of sandwich-type composite lithium metal(STCL)electrode was developed to improve its *** STCL electrode can be used as convenient as a piece of Li foil but no dendrite *** a symmetric battery,the STCL electrode cycled for more than 4500 h with the overpotential of less than 40 *** due to the creative design,the STCL promises the Li-S battery with a prolonged cycling lifespan.

关键词： Lithium metal anode Lithiophilic N-doped composite graphene Sandwich-type composite lithium metal electrode