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Microstructural evolution of titanium matrix composite coatings reinforced by in situ synthesized TiB and TiC by laser cladding

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International Journal of Minerals,Metallurgy and Materials 2010年第4期17卷 481-488页

作者： Jun li zhi-shui yu Hui-ping Wang Man-ping li School of Materials Engineering Shanghai University of Engineering Science Shanghai 201620 China

Titanium-based composite coatings reinforced by in situ synthesized TiB and TiC particles were successfully fabricated on Ti6Al4V by laser cladding using Ti-B_4C-Al or Ti-B_4C-C-Al powders as the precursor *** microstructural and metallographic analyses were made by X-ray diffraction（XRD）,optical microscope（OM）,scanning electron microscopy（SEM）,and electron probe microanalysis （EPMA）.The results show that the coatings are mainly composed ofα-Ti cellular dendrites and a eutectic transformation product in which a large number of coarse and fine needle-shaped TiB and a few equiaxial TiC particles are homogeneously embedded.A thin dilution zone with a thickness of about 100μm is present at the interface,and it consists of a few TiB and TiC reinforcements and a large number of lamella grains growing parallel to the heat flux direction in which a thin needle-shaped microstructure exists due to the martensitic transformation. The microstructural evolution can be divided into four stages：precipitation and growth of primaryβ-Ti phase,formation of the binary eutecticumβ-Ti＋TiB,formation of the ternary eutecticumβ-Ti＋TiB＋TiC,and solid transformation fromβ-Ti toα-Ti.

关键词： coating laser cladding in-situ synthesis microstructure

Syntheses of 2- or 6-Substituted Chromones and Chromone Ring-opening Reaction in Polyphosphoric Acid

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Chemical Research in Chinese Universities 2004年第3期20卷 299-304页

作者： HE Xun-gui YOU Qi-dong li zhi-yu Department of Medicinal Chemistry School of PharmacyChina Pharmaceutical UniversityNanjing 210009P.R.China Shanghai Institute of Materia Medica Chinese Academy of SciencesShanghai 201203P.R.China

In an attempt to find new antitumor agents,a novel class of chromone compounds with a benzimidazole or a benzoxazole ring in positions 2 or 6 were synthesized via condensation in polyphosphoric acid(PPA) by using chromone acids as the starting materials. During the preparation process,it was found that PPA could cleave the chromone ring to produce a ring-opening compound(6). The molar ratio of the chromone compound(5) to the ring-opening compound(6) varied with the change of reaction temperature and time. Based on MTT protocol,the antitumor activity of each of the compounds obtained was evaluated against three human cancer cell lines: KB(oral epidermal),A2780(ovary) and Bel7402(liver). The IC_ 50 varied from 54.7 μmol/L to more than 180 μmol/L.

关键词： 2-or 6-Substituted chromone Antitumor agent Polyphosphoric acid Ring-opening reaction

Oscillation properties of eigenfunctions for Sturm-liouville problems with interface conditions via Prufer transformation

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 191-200页

作者： li zhi-yu li Kun CAI Jin-ming QIN Jian-fang ZHENG Zhao-wen School of Mathematical Sciences Qufu Normal UniversityQufu 273165China College of Mathematics and Systems Science Guangdong Polytechnic Normal UniversityGuangzhou 510665China

A class of Sturm-liouville problems with discontinuity is studied in this *** oscillation properties of eigenfunctions for Sturm-liouville problems with interface conditions are *** main method used in this paper is based on Prufer transformation,which is different from the classical ***,we give two examples to verify our main results.

关键词： Sturm-liouville problem interface condition oscillatory solution

Columnar to Equiaxed Transition During Solidification of Small Ingot by Using Electric Current Pulse

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Journal of Iron and Steel Research International 2009年第6期16卷 7-12页

作者： li Jie MA Jian-hong SONG Chang-jiang li zhi-jun GAO yu-lai ZHAI Qi-jie Shanghai Key Laboratory of Modern Metallurgy and Materials Processing Shanghai University Shanghai 200072 China

A new approach to applying the electric current pulse （ECP） with parallel electrodes to the promotion of the transition from columnar crystal to equiaxed crystal and the improvement of macrosegregation was introduced. The ECP was applied to different stages of the solidification. The results showed that the application of the ECP in both the initial stage （the thickness of solidified shell reached 2 mm approximately） and the late stage （the thickness of solidified shell reached 14 mm approximately） of solidification can promote the columnar to equiaxed transition （CET）. The analysis showed that during solidification, a large number of nuclei around the upper surface fell off due to ECP, which subsequently showered on the melt and impinged the growth front of the columnar crystal. Therefore, the CEToccurred. In addition, this method was also employed to influence the solidification process of bearing steel, and the results showed that the structure was changed from columnar crystal to equiaxed crystal, indicating that ECP can enhance the homogeneity of structure and composition of bearing steel.

关键词： columnar to equiaxed transition solidification electric current pulse macrosegregation

One new bufadienolide biotransformed from cinobufagin by Cunninghamella elegans

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Chinese Chemical Letters 2008年第3期19卷 299-301页

作者： li Qiao yu zhi Zhou Huan Chen Jia Qing Cao yue Hu Pei School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 China

Cunninghamella elegans has been employed for the biotransformation of cinobufagin （1） to afford one metabolites. The structure of the transformation product has been characterized as 7β,12β-dihydroxylcinobufagin （2）. Product 2 is a new compound. In vitro cytotoxic activities of the biotransformation product and the substrate-cinobufagin have been assayed against HeLa; they all showed cytotoxic activities.

关键词： Biotransformation Cinobufagin 7β,12β-Dihydroxylcinobufagin Cunninghamella elegans

A New xanthene from Blumea riparia

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Chinese Chemical Letters 2007年第3期18卷 303-305页

作者： Jia Qing Cao Yao Yao Huan Chen li Qiao yu zhi Zhou yue Hu Pei School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University Shenyang 110016 China

A new xanthene, named blumeaxanthene, was isolated from Blumea riparia DC. The structure was elucidated on the basis of the data of NMR, MS, IR.

关键词： Blumea riparia DC. Compositae Blumeaxanthene

Initial Approach to the Cellular Irradiation Injury of Human Pancreatic Carcinoma Cell line MIA PaCa-2 by High Dose per Fraction

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Clinical oncology and cancer researeh 2010年第6期7卷 352-358页

作者： zhi-zhen WANG Hai-li yu zhi-yong yuAN Ping WANG Department of Radiation Therapy Tianjin Medical University Cancer Institute and Hospital Tianjin Key Laboratory of Cancer Prevention and Therapy Tianjin 300060 China.

OBJECTIVE To investigate an initial approach of radiotherapy, which produces cellular radiation injury by high dose in one fraction. METHODS Human pancreatic carcinoma cell line MIA PaCa-2, was cultivated and divided into 5 groups： 0, 2, 5, 10, 17 Gy. Cultivated cells were irradiated by 6MV-X ray in one fraction. Analysis were done as follows： comet assay, which assessed the level of DNA damage in the treated cells right after the cell was irradiated, flow cytometry, which was performed at 0, 6, 12, 24, 36 h after the cell line treated to ladder, which quantitatively asses changes of its cell cycle, DNA assessed the degree of DNA injury after 6 and 12 h, and histological examination, which analyzed cellular morphology after 24 h. RESULTS （1） After X-ray irradiated, the morphological change of human pancreatic carcinoma cell line （MIA PaCa-2） was mainly swelling. （2） When the dose of radiation was lower than 10 Gy, increasing the dose could greatly improve cell necrosis, apoptosis and blockage of cell cycle in GJM phase, which was consistent with the theory of radiation biology. （3） When radiation dose was more than the 10 Gy, the peak of apoptotic necrosis appeared strong and early. （4） The degree of DNA injury was also related to the dose of radiation therapy and most obvious in the 10 Gy group and not so obvious in the 17 Gy group. （5） When dose was less than 10 Gy, DNA ladder was a single electrophoretic band; in the 10 Gy group, the electrophoresis showed a multiple ladder band; when dose was more than 10 Gy, a vague and irregular band appeared on the electrophoresis. CONCLUSION Oncotic necrosis may be the main cell death style when dose per fraction is high, which differs from conventional dose fraction radiation therapy.

关键词： dose-response relationship drug necrosis irradiation injury.

Comparison of Clinical Characteristics and Outcomes of Pediatric and Adult Patients with Coronavirus Disease 2019 in Shenzhen,China

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Biomedical and Environmental Sciences 2020年第12期33卷 906-915页

作者： WANG Fang LAI Chang Xiang HUANG Peng yu liU Jia Ming WANG Xian Feng TANG Qi yuan ZHOU Xuan XIAN Wen Jie CHEN Rui Kun li Xuan li zhi yu liAO li Qun HE Qing liU Lei National Clinical Research Center for Infectious Disease Shenzhen Third People's HospitalDepartment of HepatologySecond Hospital Affiliated to Southern University of Science and TechnologyShenzhen 518112GuangdongChina Fujian Provincial Reproductive Medicine Center Fujian Maternity and Children's Hospital Affiliated to Fujian Medical UniversityFuzhou 350001FujianChina Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Hepatopancreatobiliary Surgery IPeking University Cancer Hospital&InstituteBeijing 100142China

Objective Here we aimed to investigate the difference in clinical characteristics and outcomes between pediatric and adult patients with *** A total of 333 consecutive patients with laboratory-confirmed SARS-CoV-2 infection treated in the departments of Internal medicine of Shenzhen Third People’s Hospital from January 11 th to February 10 th,2020 were *** data were obtained from electronic medical *** epidemiological data,clinical characteristics,length of hospital stays,and outcomes of pediatric and adult patients were *** Compared with adult patients,pediatric patients had a shorter time of symptom onset to hospitalization than adults[median time,1(IQR,1.0-1.0)d vs.3(IQR,2.0-6.0)d,Plinical severity classification of children was less severe than *** to 15 th March,the end of the follow-up,33(100%)children and 292(97.3%)adult patients had been discharged from *** 2(0.7%)adult patients died,with an overall case mortality of 0.6%.The median length of hospital stay of pediatric patients was shorter than that of adult patients[19(95%CI:16.6-21.4)d vs.21(95%CI:19.9-22.1)d,P=0.024].Conclusion Pediatric patients with COVID-19 had milder or less clinical symptoms,less evident pulmonary imaging changes,better prognosis,and shorter length of hospital stay.

关键词： Coronavirus disease 2019 Severe acute respiratory syndrome coronavirus 2 Clinical characteristics Pediatric patients

Occurrence and Population Dynamics of Chironomids in Early-Season Rice Fields

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Rice science 2011年第2期18卷 136-141页

作者： li zhi-yu YANG Hong LAI Feng-xiang Fu Qiang Hu Yang Institute of Entomology Guizhou University/The Provincial Key Laboratory for Agricultural Pest Management 0.1 Mountainous Region Guiyang 550025 China China National Rice Research Institute Hangzhou 310006 China

The chironomid is one of the world wide distributed insects and normally occurs in a great abundance among many kinds of water bodies. Currently, our knowledge about the chironomid in rice fields is limited to the species survey, and it is considered as a group insect at the family level, termed as a kind of the neutral insects. By using the specially designed emergence traps, the species richness and the occurrence of the chironomid in rice fields were studied throughout the early season in Fuyang City, Zhejiang Province, China. There were four species, namely, Tanytarsus formosanus, Chironomus sinicus, Polypedilum nubifer and Tanypus punctipennis of chironomids collected from rice fields. All of them are widely distributed species. T. formosanus and C. sinicus were the most dominant species in rice fields. The succession of chironomids in the early season could be divided into two phases, the early and the late phases. The abundance of the chironomid was higher in the early phase than that in the late phase. It was estimated that there were around 3 million individuals of chironomids emerged from 667 m2 rice field throughout the early season. It was also found that the sex ratio of T. formosanus was female-biased during the early phase, whereas male-biased during the late phase. In contrast, the sex ratio of C. sinicus was male-biased throughout the early season.

关键词： rice field chironomid population dynamic sex ratio