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Role of fragmentation in as-cast structure:numerical study and experimental validation

China Foundry 2017年第5期14卷 321-326页

作者： yong-jian zheng Meng-huai Wu A.Kharicha A.Ludwig Chair of Simulation and Modelling of Metallurgical Processes Montanuniversitaet Leoben Christian Doppler Laboratory for Advanced Process Simulation of Solidification and Melting Department of Metallurgy University of Leoben

A volume average solidification model is extended to incorporate fragmentation as the source of equiaxed crystals during mixed columnar-equiaxed solidification. This study is to use this model to analyze the role of fragmentation in the formation of as-cast structure. Test simulations are made for the solidification of a model alloy(Sn-10wt.%Pb) with two different geometries. The first one is a 2D rectangular domain(50 × 60 mm^2) as cooled from the top boundary. Solidification starts unidirectionally as columnar structure from the top. The solute(Pb) enriched interdendritic melt is heavier than the bulk melt, and sinks downwards, hence leads to solutal convection. Fragmentation phenomenon occurs near the columnar tip front. The fragments are transported out of the columnar region, and they continue to grow and sink, and finally settle down and pile up at the bottom. The growing columnar structure from the top and pile-up of equiaxed crystals from the bottom finally lead to a mixed columnar-equiaxed structure, in turn leading to a columnar-to-equiaxed transition(CET). The second geometry is a 3D plate, 100 × 60 ×10 mm^3, as cooled laterally from one side. It was cast experimentally and analyzed for the as-cast structure. The equiaxed fragments are produced in the solidification front and transported into the bulk melt, leading to a special pattern of as-cast structure: columnar structure in the cool wall side and equiaxed structure in the upper left corner near the hot wall side, extending downwards to the middle bottom region. Numerically calculated as-cast structures agree with the experiment results.

关键词： macrostructure interdendritic fluid flow fragmentation

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Effect of p27^(KIP1) on cell cycle and apoptosis in gastric cancer cells

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World Journal of Gastroenterology 2005年第45期11卷 7072-7077页

作者： jian-yong zheng Wei-Zhong Wang Kai-Zong Li Wen-Xian Guan Wei Yan Department of Gastrointestinal Surgery Xijing Hospital FourthMilitary Medical University Xi'an 710032 Shaanxi ProvinceChina Department of Hepatobiliary Surgery XijingHospital Fourth Military Medical University Xi'an 710032Shaanxi Province China Department of Pathology Fourth Military MedicalUniversity Xi'an 710032 Shaanxi Province China

AIM： To elucidate the effect of p27^KIP1 on cell cycle and apoptosis regulation in gastric carcinoma cells. METHODS： The whole length of p27^KIP1 cDNA was transfected into human gastric cancer cell line SCG7901 by lipofectamine. Expression of p27^KIP1 protein or mRNA was analyzed by Western blot and RNA dot blotting, respectively. Effect of p27^KIP1 on cell growth was observed by MTT assay and anchorage-independent growth in soft agar. Tumorigenicity in nude mice was used to assess the in vivo biological effect of p27^KIP1. Flow cytometry, TUNEL, and electron microscopy were used to assess the effect of p27^KIP1 on cell cycle and apoptosis. RESULTS： Expression of p27^KIP1 protein or mRNA increased evidently in SCG7901 cells transfected with p27^KIP1. The cell growth was reduced by 31% at 48 h after induction with zinc determined by cell viability assay. The alteration of cell malignant phenotype was evidently indicated by the loss of anchorage-independent growth ability in soft agar. The tumorigenicity in nude mice was reduced evidently （0.55±0.14 cm vs 1.36±0.13cm, P〈0.01）. p27^KIP1 overexpression caused cell arrest with 36% increase （from 33.7% to 69.3%, P〈0.01） in G1 population. Prolonged p27^KIP1 expression induced apoptotic cell death reflected by pre-G1 peak in the histogram of FACS, which was also confirmed by TUNEL assay and electron microscopy. CONCLUSION： p27^KIP1 can prolong cell cycle in G1 phase and lead to apoptosis, p27^KIP1 may be a good candidate for cancer gene therapy.

关键词： Cell cycle Apoptosis Gastric neoplasm p27^KIP1

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Rotary bending fatigue behavior of A356 –T6 aluminum alloys by vacuum pressurizing casting

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China Foundry 2015年第5期12卷 326-332页

作者： yong-qin Liu Wan-qi Jie Zhi-ming Gao yong-jian zheng Hai-jun Luo Wen-tao Song State Key Laboratory of Solidification Processing Northwestern Polytechnical University School of Aerospace Mechanical and Manufacturing Engineering RMIT University Simulation and Modeling of Metallurgical Processes Montanuniversitaet Leoben

Vacuum pressurizing casting technique, providing better mould filling and inter-dendritic feeding, can reduce the porosity greatly in cast aluminum alloys, and improve the fatigue properties. The rotary bending fatigue properties of A356-T6 alloys prepared by vacuum pressurizing casting were investigated. The S-N curve and limit strength 90 MPa under fatigue life of 107 cycles were obtained. The analyses on the fatigue fractography and microstructure of specimens showed that the fatigue fracture mainly occurs at the positions with casting defects in the subsurface, especially at porosities regions, which attributed to the crack propagation during the fatigue fracture process. Using the empirical crack propagation law of Pairs-Erdogon, the quantitative relationship among the initial crack size, fatigue life and applied stress was established. The fatigue life decreases with an increase in initial crack size. Two constants in the Pairs-Erdogon equation of aluminum alloy A356-T6 were calculated using the experimental data.

关键词： aluminum alloys vacuum pressurizing casting rotary bending fatigue porosity crack propagation

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Thrombus straddling a patent foramen ovale and pulmonary embolism:A case report

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World Journal of Clinical Cases 2020年第20期8卷 4902-4907页

作者： Yi-Xiong Huang Yu Chen Yi Cao Yi-Gang Qiu jian-yong zheng Tian-Chang Li Department of Cardiology Sixth Medical Center of PLA General HospitalBeijing 100048China

BACKGROUND Venous thromboembolism is a common vascular syndrome presenting as deep vein thrombosis and/or pulmonary *** has the possibility of migrating into the left circulation via patent foramen ovale in certain extreme *** straddling a patent foramen ovale is a direct evidence of this ***,the confirmed cases of thrombus in transit are still *** SUMMARY A 32-year-old man suffered from recurrent syncope and intermittent dyspnea for 1 *** echocardiography confirmed a thrombus straddling the patent foramen ovale,and thrombi were also found in the bilateral pulmonary artery by computed *** man underwent inferior vena cava filter placement and thrombolysis with *** showed the absence of thrombi in both the right atrium and left atrium 2 d after *** man was discharged to home on warfarin without any complications 2 wk *** Scrutinizing intracardiac thrombi provides measurable value in pulmonary embolism as closure of patent foramen ovale may be considered in certain *** intervention plays a critical role in thrombus straddling a patent foramen ovale.A sedentary lifestyle may predispose young adults to thromboembolism,even if there are no other risk factors.

关键词： Thrombus Patent foramen ovale Pulmonary embolism Case report

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Overexpression of Bax induces apoptosis and enhances drug sensitivity of hepatocellular cancer-9204 cells

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World Journal of Gastroenterology 2005年第23期11卷 3498-3503页

作者： jian-yong zheng Guang-Shun Yang Wei-Zhong Wang Wen-Xian Guan jiang Li Wen-Liang Wang Kai-Zong Li Department of Laparoscope Eastern HepatobiliarySurgery HospitalSecond Military Medical UniversityShanghai 200438China Department of Gastrointestinal Surgery Xijing HospitalFourth Military Medical UniversityXi'an 710032Shaanxi ProvinceChina Department of Pathology Fourth Military Medical UniversityXi'an 710032Shaanxi ProvinceChina Department of Hepatobiliary Surgery Xijing HospitalFourth Military Medical UniversityXi'an 710032Shaanxi ProvinceChina

AIM: To investigate the role of overexpression of Bax in apoptotic pathways and the response of human hepatocellular cancer (HCC)-9204 cells to cell death induced by ***: The whole length of Bax cDNA was transfectrd into human HCC-9204 cells by the method of lipofectamine transfection. An inducible MT-Ⅱ regulatory system was constructed, which allowed controlled expression of protein upon addition of ZnSO4 (100 μmol/L) as an external inducer. Stable transfecting inducible expression vector containing Bax gene was performed. Expression of Bax in protein was analyzed by immunohistochemistry and Western blotting. TUNEL and flow cytometry were used to assess the effect of Bax on apoptosis. Colony assay and tetrazolium blue (MTT) assay were used to evaluate the difference in drug sensitivity of HCC-9204 cells after ***: Immunohistochemistry and Western blotting demonstrated that the expression of Bax protein markedly increased in Bax-transfected cells 4 h after the addition cytoplasm and perinuclear region of HCC-9404 cells, and there was ectopic expression in cells with marked condensation of chromatin and cytoplasm (apoptotic cells). Apoptotic index significantly increased in Bax-transfected HCC-9204/Bax cells (3.6 vs 27.2, 4.2 vs 32.3, P＜0.05).Flow cytometry analysis showed a significant sub-G1 peak and apoptosis in 15.4% HCC-9204/Bax cells 24 h after treatment. Furthermore, colony survival rate decreased from 66% (HCC-9204/pMD) to 45% (HCC-9204/Bax) 2 dafter ADR withdrawal. MTT assay result showed that the effects of Bax on cell viability following ADR exposure were significant as compared to the vehicle-transfected HCC-9204/pMD cells (21% vs 44%, P＜0.01).CONCLUSION: Overexpression of Bax not only induces apoptosis, but also sensitizes HCC-9204 cells to cell death induced by adriamycin.

关键词： Bax Apoptosis Hepatocellular carcinoma

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Frequency domain wave equation forward modeling using gaussian elimination with static pivoting

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Applied Geophysics 2011年第1期8卷 60-68,95页

作者： Song jian-yong zheng Xiao-Dong Zhang Yan Xu Ji-Xiang Qin Zhen Song Xue-Juan Research Department of Geophysics Research Institute of Petroleum Exploration and Development Beijing 10083 China

Frequency domain wave equation forward modeling is a problem of solving large scale linear sparse systems which is often subject to the limits of computational efficiency and memory storage. Conventional Gaussian elimination cannot resolve the parallel computation of huge data. Therefore, we use the Gaussian elimination with static pivoting （GESP） method for sparse matrix decomposition and multi-source finite-difference modeling. The GESP method does not only improve the computational efficiency but also benefit the distributed parallel computation of matrix decomposition within a single frequency point. We test the proposed method using the classic Marmousi model. Both the single-frequency wave field and time domain seismic section show that the proposed method improves the simulation accuracy and computational efficiency and saves and makes full use of memory. This method can lay the basis for waveform inversion.

关键词： Gaussian elimination with static pivoting frequency-domain wave equation forward modeling single-frequency distributed parallel

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A Genetic Linkage Map of Brassica campestris ***. pekinensis (syn. B. rapa L. ssp. pekinensis)

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Agricultural Sciences in China 2003年第1期2卷 49-55页

作者： YU Shuan-cang, WANG yong-jian and zheng Xiao-yingBeijing Vegetable Research Center, Beijing 100089 , P. R. China

A molecular genetic map of Chinese cabbage was constructed with a 102 recombinant inbred (RI) population from a cross of two cultivated Chinese cabbage lines 177 and 276, using AFLP and RAPD markers. 352 markers including 265 AFLP markers and 87 RAPD markers were integrated into 17 linkage groups. It covered a total of 2 665. 7 cM with an average interval of 7. 6 cM. AFLP marker is efficient for map construction while it easily forms clusters to cause big gaps in map. A total of 13.92 % abnormal segregation markers distributed in the map. The molecular genetic map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.

关键词： Brassica campestris L. ssp. pekinensis(syn. B. rapa L. ssp. pekinensis) Genetic linkage map AFLP RAPD

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The forbidden transitions for magnesium isoelectronic sequences

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原子与分子物理学报 2001年第3期18卷 317-324页

作者： YI You-gen 1,2,3 , ZHU zheng-he 2,TANG yong-jian 3 zheng Zhi-jian 3 (1.Department of Physics, Xiangtan Normal College,Xiangtan 411201 2.Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 3.Southwestern Institu 湘潭师范学院湖南湘潭 411201 四川大学四川成都 610065 中国工程物理研究院西南核物理与化学所四川成都 610003

Using the full relativistic quantum mechanics (GRASP2), we have calculated systematically the 3P 2- 3P 1 and 3P 1- 3P 0 magnetic dipole M1 energy level separations, transition probabilities and oscillator strengths in the 3s3p configuration of the magnesium sequences. The two configurations 3s3p and 3p3d are used. Breit and QED effects are treated as high-order perturbations. Excellent comparison is obtained throughout the range of atomic number Z, and the inclusion of the 3p3d configuration gives results which are in good agreements with recent experimental and reference data.

关键词：镁原子禁戒跃迁等电子数序

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Numerical simulation for macrosegregation in direct-chill casting of 2024 aluminum alloy with an extended continuum mixture model

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Transactions of Nonferrous Metals Society of China 2018年第5期28卷 1007-1015页

作者： Hai-jun LUO Wan-qi JIE Zhi-ming GAO yong-jian zheng State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China Chair of Simulation and Modeling of Metallurgical Processes Montan Universitaet Leoben 8700 Leoben Austria

An extended continuum mixture model for macrosegregation is applied to predicting Cu and Mg segregation in large-size ingot of 2024 aluminum alloy during direct chill casting（DC）. A microsegregation model using the approximate phase diagram data was coupled with macroscopic transport equations for macrosegregation profiles. Then, the impacts of transport mechanisms on the formation of macrosegregation were discussed. It is found that copper and magnesium have a similar segregation configuration from the billet center to surface. Negative segregation is observed in the centerline and subsurface, whereas positive segregation is obtained in the surface and somewhat underestimated positive segregation in the middle radius. Further, the discrepancy between the predicted and experimental results was discussed in detail. The results show that the magnesium to some extent alleviates the copper segregation in ternary alloy, compared with that in binary alloy. The predicted results show good agreement with measured experimental data obtained from literatures.

关键词： direct-chill casting macrosegregation numerical simulation continuum model 2024 aluminum alloy

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Low-grade metamorphic rocks in the Dabie-Sulu orogenic belt:A Passive-margin accretionary wedge deformed during continent subduction

Low-grade metamorphic rocks in the Dabie-Sulu orogenic belt:...

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中生代以来中国大陆板块作用过程学术研讨会

作者： yong-Fei zheng, jian-Bo ZHOU Yuan-Bao Wu School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026

＜正＞Duringsubuctionofanoceanicplate,marinesedimentsandunderlyingrocksgenerallycanbescrapedo***-marginaccretio***edbythesubductionofanoceanicplate,butitislessoftenreportedforanorogenicbeltresultingfromthesubductionofa

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