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Ohmic contact properties of p-type surface conductive layer on H-terminated diamond films prepared by DC arc jet CVD

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 802-807页

作者： Jin-long Liu cheng-ming Li Rui-hua Zhu Liang-xian chen Jing-jing Wang Zhi-hong Feng School of Materials Science and Engineering University of Science and Technology Beijing Science and Technology on ASIC Laboratory Hebei Semiconductor Research Institute

With the advantages of high deposition rate and large deposition area, polycrystalline diamond films prepared by direct current （DC） arc jet chemical vapor deposition （CVD） are considered to be one of the most promising materials for high-frequency and high-power electronic devices. In this paper, high-quality self-standing polycrystalline diamond films with the diameter of 100 mm were prepared by DC arc jet CVD, and then, the p-type surface conductive layer with the sheet carrier density of 10^11-10^13 cm-2 on the H-terminated diamond film was obtained by micro-wave hydrogen plasma treatment for 40 min. Ti/Au and Au films were deposited on the H-terminated diamond surface as the ohmic contact electrode, respectively, afterwards, they were treated by rapid vacuum annealing at different temperatures. The properties of these two types of ohmic contacts were investigated by measuring the specific contact resistance using the transmission line method （TLM）. Due to the formation of Ti-related carbide at high temperature, the specific contact resistance of Ti/Au contact gradually decreases to 9.95 × 10^-5 Ω-cm2 as the temperature increases to 820℃. However, when the annealing temperature reaches 850℃, the ohmic contact for Ti/Au is degraded significantly due to the strong diffusion and reaction between Ti and Au. As for the as-deposited Au contact, it shows an ohmic contact. After annealing treatment at 550℃, low specific contact resistance was detected for Au contact, which is derived from the enhancement of interdiffusion between Au and diamond films.

关键词： polycrystalline materials diamond films chemical vapor deposition ohmic contacts contact resistance

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Solvent-Controlled Construction of Molecular Chains and Bowls/Sieves from a Bent Dipyridyl Ligand

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Chinese Journal of Chemistry 2021年第9期39卷 2523-2528页

作者： Xiao-Yun Tian Xiao-xian chen Chao Wang Zi-Ming Ye Dong-Dong Zhou Jie-Peng Zhang MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of ChemistrySun Yat-Sen UniversityGuangzhouGuangdong 510275China

Solvothermal reactions of 3,6-di(pyridin-4-yl)-9H-carbazole(dpc)with Cu(ll)yielded crystals of two new coordination complexes,namely[Cu(CH_(3)COO)_(2)(dpc)(H_(2)O)_(2)]n-xGuest(1)and[Cu_(13)(HCOO)_(16)(dpc)16(H_(2)O)6](HCOO)10-Guest(2),in which CH_(3)COO_and HCOO-were generated from the hydrolysis of the solvents A/zAZ-dimethylacetamide(DMA)and A/zA/-dimethylformamide(DMF),***-crystal X-ray diffraction showed that 1 possesses simple wavy coordination chains,while 2 possesses large molecular bowls/sieves with outer and inner effective sizes of 30.2 × 30.2 × 25.5 A^(3) and 15.0 × 15.0 × 18.6 A^(3),respectively,which consists of 4 linear Cu_(3)(HCOO)_(4)(H_(2)O)clusters and 12 dpc ligands as the square-shaped wall and a claw-like Cu(dpc)_(4) fragment as the ***-free 2 can adsorb considerable amounts of CO_(2)/H_(2)O and CH_(3)OH but completely exclude C2H4 and C3H6z which shows a potential application for olefin drying.

关键词： Self-assembly Crystal engineering Microporous materials Molecular sieve Olefin drying

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Deposition of crackless freestanding diamond films on Mo substrates with Zr interlayer

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 246-250页

作者： Zheng Liu cheng-ming Li Liang-xian chen Li-mei Wang Li-fu Hei Fan-xiu Lu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The Mo substrate with Zr interlayer,namely composite substrate,was employed to solve the problem of crack formation in the freestanding diamond film *** diamond films deposited on the composite substrates by the direct current arc plasma jet chemical vapor deposition（CVD） method were investigated with scanning electron microscopy（SEM）,X-ray photoelectron spectroscopy （XPS）,X-ray diffraction（XRD）,and Raman *** addition,the stress distribution during the large area freestanding diamond film deposition on the composite substrate was analyzed based on the finite element model *** results reveal that Zr interlayer can be easily destroyed during the post-deposition cooling process,which is helpful for stress release and crack avoiding in diamond films.

关键词： chemical vapor deposition diamond film interlayer thermal stress finite element analysis

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Orientation variation along growth direction of millimeter free-standing CVD diamond thinned by mechanical grinding

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International Journal of Minerals,Metallurgy and Materials 2014年第8期21卷 839-844页

作者： Xing-kai Wen Jun-jun Wei Jin-long Liu Jian-chao Guo Liang-xian chen cheng-ming Li Institute of Advanced Materials and Technology University of Science and Technology Beijing

A free-standing diamond film with millimeter thickness prepared by DC arc plasma jet was thinned successively by mechanical grinding. The orientation and quality of the diamond films with different thicknesses were characterized by X-ray diffraction and Raman spectroscopy, respectively. The results show a random grain-orientatinn distribution during the initial growth stage. As the film thickness increases, the preferred orientation of the diamond film changes from （111） to （220）, due to the competitive growth mechanism. Twinning generated during the nucleation stage appears to stabilize the preferential growth along the 〈110〉 direction. The interplanar spacing of the （220） plane is enlarged as the film thickness increases, which is caused by the increase of non-diamond-phase carbon and impurities under the cyclic gas. In addition, the quality of the diamond film is barely degraded during the growth process. Furthermore, the peak shift demonstrates a significant inhomogeneity of stress along the film growth direction, which results from competitive growth.

关键词： diamond films chemical vapor deposition grinding orientation growth mechanisms quality

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Direct electrochemistry and electrocatalysis of myoglobin in dodecyltrimethylammonium bromide film modified carbon ceramic electrode

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Chinese Chemical Letters 2011年第4期22卷 465-468页

作者： Yuan Zhen Zhou Hui Wang She Ying Dong An xiang Tian Zhi xian He Bin chen School of Science Xi'an University of Architecture and TechnologyXi'an 710055China

Direct electrochemistry and electrocatalysis of myoglobin（Mb） were studied with Mb immobilized on dodecyltrimethylammonium bromide（DTAB） film modified carbon ceramic（CC） *** voltammetry showed a pair of well-defined and nearly reversible redox peaks of Mb（Fe~Ⅱ/Fe~Ⅲ） at about—0.3 V ***（pH = 6.98）.The currents of the redox peak were linear to scan rate,and rate constant（Ks） was estimated to be 3.03 s^（-1）.The formal potential（E°＇） of Mb in the DTAB/CC electrodes shifted linearly with pH with a slope of -36.44 mV/pH,implying that the electron transfer between DTAB and CC electrodes is accompanied by proton *** immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide（H2O2）.

关键词： Electrocatalysis Direct electron transfer DTAB H_2O_2 Myoglobin

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Lymphocyte-to-monocyte ratio effectively predicts survival outcome of patients with obstructive colorectal cancer

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World Journal of Gastroenterology 2019年第33期25卷 4970-4984页

作者： xian-Qiang chen Chao-Rong Xue Ping Hou Bing-Qiang Lin Jun-Rong Zhang Department of General Surgery(Emergency Surgery) Fujian Medical University Union HospitalFuzhou 350001Fujian ProvinceChina Immunotherapy Institute Fujian Medical UniversityFuzhou 350122Fujian ProvinceChina

BACKGROUND Obstructive colorectal cancer(OCC)is always accompanied by severe complications,and the optimal strategy for patients with OCC remains *** from emergency surgery(ES),self-expandable metal stents(SEMS)as a bridge to surgery(BTS),could increase the likelihood of primary ***,the stent failure and related complications might give rise to a high recurrence *** studies have focused on the indications for either method,and the relationship between preoperative inflammation indexes and the prognosis of OCC is still *** To explore the indications for ES and BTS in OCCs based on preoperative inflammation *** One hundred and twenty-eight patients who underwent ES or BTS from 2008 to 2015 were *** operating characteristic(ROC)curve analysis was used to define the optimal preoperative inflammation index and its cutoff ***–Meier analyses and Cox proportional hazards models were applied to assess the association between the preoperative inflammation indexes and the survival outcomes[overall survival(OS)and disease-free survival(DFS)].Stratification analysis was performed to identify the subgroups that would benefit from ES or *** OS and DFS were comparable between the ES and BTS groups(P>0.05).ROC curve analysis showed derived neutrophil-to-lymphocyte ratio(dNLR)as the optimal biomarker for the prediction of DFS in ES(P<0.05).Lymphocyte-tomonocyte ratio(LMR)was recommended for BTS with regard to OS and DFS(P<0.05).dNLR was related to stoma construction(P=0.001),pneumonia(P=0.054),and DFS(P=0.009)in *** was closely related to lymph node invasion(LVI)(P=0.009),OS(P=0.020),and DFS(P=0.046)in the BTS *** was an independent risk factor for ES in both OS(P=0.032)and DFS(P=0.016).LMR affected OS(P=0.053)and DFS(P=0.052)in the BTS *** could differentiate the OS between the ES and BTS groups(P<0.05).CONCLUSION Preoperative dNLR and LMR could predict OS and DFS in pat

关键词： Inflammation indexes Emergency surgery Self-expanding metal stent insertion as a bridge to surgery Obstructive colorectal cancers

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Stapled transperineal repair for low-and mid-level rectovaginal fistulas:A 5-year experience and comparison with sutured repair

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World Journal of Gastroenterology 2021年第14期27卷 1451-1464页

作者： Qian Zhou Zhi-Min Liu Hua-xian chen Dong-Lin Ren Hong-cheng Lin Department of Coloproctology The Sixth Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510655Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases The Sixth Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510655Guangdong ProvinceChina Guangdong Institute of Gastroenterology The Sixth Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510655Guangdong ProvinceChina

BACKGROUND Currently,rectovaginal fistula(RVF)continues to be a surgical challenge worldwide,with a relatively low healing *** intermittent suture and poor suture materials may be the main reasons for *** To evaluate the efficacy and safety of stapled transperineal repair in treating *** This was a retrospective cohort study conducted in the Coloproctology Department of The Sixth Affiliated Hospital of Sun Yat-sen University(Guangzhou,China).Adult patients presenting with RVF who were surgically managed by perineal repair between May 2015 and May 2020 were *** the 82 total patients,37 underwent repair with direct suturing and 45 underwent repair with *** demographic data,Wexner faecal incontinence score,and operative data were *** rate and associated risk factors were *** The direct suture and stapled repair groups showed similar clinical characteristics for aetiology,surgical history,fistula features,and perioperative Wexner *** stapled repair group did not show superior results over the suture repair group in regard to operative time,blood loss,and hospital ***,the stapled repair group showed better postoperative Wexner score(1.04±1.89 vs 2.73±3.75,P=0.021),less intercourse pain(1/45 vs 17/37,P=0.045),and lower recurrence rate(6/45 vs 17/37,P=0.001).There was no protective effect from previous repair history,smaller diameter of fistula(10)were risk factors for fistula ***,stapled repair gave better efficacy in treating complex RVFs(i.e.,multiple transperineal repair history,mid-level fistula position,and poor control of defecation).CONCLUSION Stapled transperineal repair is advantageous for management of RVF,providing a high primary healing rate and low recurrence rate.

关键词： Rectovaginal fistula Surgical repair Transperineal approach Stapled technique Recurrence

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Role of tropical cyclones over the western North Pacific in the East Asian summer monsoon system

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Earth and Planetary Physics 2019年第2期3卷 147-156页

作者： xian chen Zhong Zhong YiJia Hu Shi Zhong Wei Lu Jing Jiang China Aerodynamics Research and Development Center College of Meteorology and Oceanography National University of Defense Technology Jiangsu Collaborative Innovation Center for Climate Change Nanjing University State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University

Precipitation observations collected at weather stations in eastern China, the NCEP/NCAR reanalysis data, the tropical cyclone(TC) Best Track Dataset, and a sensitivity numerical experiment were used in the present study to investigate the role in the East Asian summer monsoon(EASM) system played by frequent TC activities over the western North Pacific(WNP). Results indicated that, in active TC years, the EASM is stronger and the southerly winds in the lower troposphere advance farther north and reach higher ***, the monsoon rain belt remains in the lower and middle reaches of the Yangtze River valley for a relatively short period,leading to less precipitation there. Both the western Pacific subtropical high and the South Asian high weaken with the northward shift of the ridgelines for both high-pressure systems as well as the East Asian subtropical upper-level jet. Therefore, the impacts of frequent TC activities over the WNP on each individual component of the EASM are in phase with those of the stronger EASM itself, amplifying features of the already strengthened EASM.

关键词： East Asian summer monsoon tropical cyclone western North Pacific

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Effect of Ti Particles on the Microstructure and Mechanical Properties of AZ91 Magnesium Matrix Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 513-524页

作者： Lu Xiao Ting-Ting Liu Yue Chu Bo Song Jie Zhao xian-Hua chen Kai-Hong Zheng Fu-Sheng Pan College of Materials Science and Engineering Chongqing UniversityChongqing 400044China lntelligent Manufacturing and Automobile School Chongqing College of Electronic EngineeringChongqing 401331China School of Materials and Energy Southwest UniversityChongqing 400715China Science and Technology Research Institute of CNNC 404 Co.LTD Gansu 735100China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China

Spherical micro-Ti particle(TiP)-reinforced AZ91 magnesium alloy composites were fabricated by semi-solid stirring assisted ultrasonic vibration,which were then subjected to hot *** microstructure results showed that the addition of Ti particles refined the grain size and decreased the texture intensity of the as-extruded AZ91 *** Al3Ti phase with a thickness of 100 nm formed at the Ti/Mg interface,which had a non-coherent relationship with the magnesium *** as-extruded 1 vol.%TiP/AZ91 composite exhibited the best comprehensive mechanical properties,with yield strength,ultimate tensile strength,and elongation at break of 366 MPa,456 MPa,and 14.6%,respectively,which were significantly higher than those of the AZ91 ***,the addition of Ti particles can improve the strength and ductility of the AZ91 alloy,demonstrating the value of magnesium matrix composites for commercial applications.

关键词： Magnesium matrix composites Ti particles Interface Mechanical properties

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Perspective on the Development of Traditional Chinese Medicine and World Medicine

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World Journal of Traditional Chinese Medicine 2020年第1期6卷 1-11页

作者： Kai-xian chen School of Traditional Chinese Materia Medica Shanghai University of Traditional Chinese MedicineShanghaiChina

Following the spirit of Central Committee about the Opinions on Promoting the Inheritance, Innovation and Development of Traditional Chinese Medicine, professor Kai-xian chen, from Shanghai University of Traditional Chinese Medicine, delivered a comprehensive lecture on the development of traditional Chinese medicine (TCM) and world medicine. The lecture deeply elaborated on five aspects:the characteristics and advantages of TCM, the challenges faced by contemporary medicine, the status and role of TCM in the contemporary era, the inheritance and innovation of TCM, and the cooperation and development of "Belt and Road".

关键词： “Belt and Road” characteristics and advantages of TCM contemporary medicine global medicine inheritance and innovation of TCM TCM traditional chinese medicine

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