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Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

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Nuclear Science and Techniques 2024年第3期35卷 84-95页

作者： Lei Peng Yong-Jie Sun jing-yi shi yi-Fei Liu Shang-Ming Chen Liu-Liu Li State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213China

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion *** order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics *** results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile *** atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation ***,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at *** bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation ***,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

关键词： Helium bubble Grain boundary Embrittlement Reduced activation ferritic martensitic steel Molecular dynamics Bain path

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Scleral TGF-β1 and Smad3 expression is altered by TCM Bu jing yi shi Tablets in guinea pigs with form-deprivation myopia

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Journal of Traditional Chinese Medical Sciences 2016年第2期3卷 124-132页

作者： Ya Mo yi Wang Bin Cao Jiajia Zhang Guoting Ren Ting Yang Department of Ophthalmology The Affiliated Hospital of Chengdu University of TCMChengdu 610072China Department of Pathology The Affiliated Hospital of Chengdu University of TCMChengdu 610072China

Objective:To explore whether the traditional Chinese medicine(TCM)Bu jing yi shi Tablets alters the expression of scleral TGF-b1 and Smad3 in guinea pigs with formdeprivation myopia(FDM).Methods:Sixty-five guinea pigs were randomly divided into control,model,low-,medium-,and high-dose treatment *** for the control group,FDM was induced by covering the right eye of each animal with opaque *** treatment groups were gavaged with different suspension concentrations of Bu jing yi shi *** and axial length were performed before and after myopia *** the end of the experiment,all right eyes were extracted,and scleral sections were prepared for staining and TGF-b1 and Smad3 *** thickness and area,the scleral fibroblast quantity,and scleral TGFb1 and Smad3 expressions were ***:The 5 FDM groups had the same initial axial length and diopter,the final diopter and axial length of the model group were significantly increased compared with the control group and treatment groups(P<.01).The axial length of each treatment group decreased as the dose decreased compared with the model group(P<.01);the total scleral area(P<.05 e.01)and the number of scleral fibroblasts(P<.01)in the model group were significantly lower than the treatment *** the TGF-b1 and Smad3 integral optical densities in the model group were significantly lower than the control and medium-and high-dose treatment groups(P<.01).TGF-b1 and Smad3 mRNAs in the model group were decreased compared with the control group,but increased in expression after treatment.

关键词： TCM Form-deprivation myopia Sclera TGF-b1 Smad3

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Grain boundary engineering for enhancing intergranular damage resistance of ferritic/martensitic steel P92

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Nuclear Science and Techniques 2024年第5期35卷 186-199页

作者： Lei Peng Shang-Ming Chen jing-yi shi Yong-Jie Sun yi-Fei Liu yin-Zhong Shen Hong-Ya He Hui-Juan Wang Jie Tian State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China School of Nuclear Science and Technology University of Science and Technology of ChinaHefei 230027China School of Materials Engineering Shanghai University of Engineering Science333 Long Teng RoadShanghai 201620China Experimental Center of Engineering and Material Science University of Science and Technology of ChinaHefei 230026China

Ferritic/martensitic(F/M)steel is widely used as a structural material in thermal and nuclear power ***,it is susceptible to intergranular damage,which is a critical issue,under service *** this study,to improve the resistance to intergranular damage of F/M steel,a thermomechanical process(TMP)was employed to achieve a grain boundary engineering(GBE)microstructure in F/M steel *** TMP,including cold-rolling thickness reduction of 6%,9%,and 12%,followed by austenitization at 1323 K for 40 min and tempering at 1053 K for 45 min,was applied to the as-received(AR)P92 *** prior austenite grain(PAG)size,prior austenite grain boundary character distribution(GBCD),and connectivity of prior austenite grain boundaries(PAGBs)were *** to the AR specimen,the PAG size did not change *** fraction of coincident site lattice boundaries(CSLBs,3≤Σ≤29)and Σ3^(n) boundaries along PAGBs decreased with increasing reduction ratio because the recrystallization fraction increased with increasing reduction *** PAGB connectivity of the 6%deformed specimen slightly deteriorated compared with that of the AR ***,potentiodynamic polarization studies revealed that the intergranular damage resistance of the studied steel could be improved by increasing the fraction of CSLBs along the PAGBs,indicating that the TMP,which involves low deformation,could enhance the intergranular damage resistance.

关键词： Grain boundary engineering Ferritic/martensitic steel Prior austenite grain boundary character distribution Grain boundary connectivity Intergranular damage resistance

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Electrophysiological characteristics of cardiomyocyte-like cells from rat bone marrow derived mesenchymal stem cells by four inductors

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Chinese Medical Journal 2013年第18期126卷 3528-3533页

作者： LIU Bo-wu LU An-lin HOU jing HUANG Wei HOU Hong HOU Zhao-lei DA jing AI shi-yi Department of Cardiology Xijing Hospital Fourth Military Medical University Xi'an Shaanxi 710032 China

Background Bone marrow derived mesenchymal stem cel induced by different inductors individually or collectively. In s （BMdMSCs） can differentiate into cardiomyocyte-like cells this study, by inducing BMdMSCs with p53 inhibitor （p-fifty three inhibitor-alpha, PFT-a）, 5-azacytidine （5-AZA）, angiotensin-II （Ang-II） and bone morphogenic protein-2 （BMP-2） we compared the influences of four inductors on the differentiation of rat BMdMSCs into caridomyocyte like-cells. Methods BMdMSCs were collected from the bone marrow of Sprague Dawley rats and after the fourth generation, the purified cells were divided into five groups： 5-AZA （10 μmol/L）, Ang-II （0.1 μmol/L）, PFT-α （20 μmol/L）, BMP-2 （10μg/L） and control. The purity of the BMdMSCs and the cardiac differentiation rates were obtained by flow cytometry. The expressions of cTnT in the BMdMSCs after four weeks of induction were detected by immunofluorescence and the expressions of cTnl and Cx43 detected by Western blotting. The green fluorescent levels reflecting intracellular calcium transient function were determined by laser scanning confocal microscopy. The total potassium current levels of cells were measured on patch clamp. Results All inductors affected to a different degree the differentiation of BMdMSCs into cardiomyocyte-like cells and the expressions of cTnT, cTnl and Cx43 suggesting that the combination of inductors could be an improved method for cardiac regenerative medicine. In addition, the total potassium current level and calcium transient in PFT-a cardiomyocyte-like cells were higher than other groups. Conclusions The cardiac differentiation of BMdMSCs induced by PFT-α, 5-AZA, Ang-II and BMP-2 has been improved at different levels. PFT-a has an advantage of differentiation rate and electrophysiological function over other inductors.

关键词： bone marrow mesenchymal stem cells differentiation cardiomyocyte electrophysiological characteristics

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Mucinous adenocarcinoma:A unique clinicopathological subtype in colorectal cancer

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World Journal of Gastrointestinal Surgery 2021年第12期13卷 1567-1583页

作者： An Huang Yong Yang jing-yi shi Yu-Kun Li jing-Xuan Xu Yu Cheng Jin Gu Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Gastrointestinal Surgery IIIPeking University Cancer Hospital&InstituteBeijing 100142China Peking-Tsinghua Center for Life Science Peking University International Cancer CenterBeijing 100142China Department of Gastrointestinal Surgery Peking University Shougang HospitalBeijing 100144China

Mucinous adenocarcinoma(MAC)is a unique clinicopathological subtype of colorectal cancer,which is characterized by extracellular mucinous components that comprise at least 50%of the tumor *** clinical characteristics,molecular features,response to chemo-/radiotherapy,and prognosis of MAC are different from that of non-MAC(NMAC).MAC is more common in the proximal colon,with larger volume,higher T-stage,a higher proportion of positive lymph nodes,poorer tumor differentiation,and a higher proportion of peritoneal implants compared to *** biopsy is the main diagnostic method for MAC,magnetic resonance imaging is superior in accuracy,especially for rectal *** aberrant expression of mucins,including MUC1,MUC2 and MUC5AC,is a notable feature of MAC,which may be related to tumor invasion,metastasis,inhibition of apoptosis,and chemo-/radiotherapy *** genetic origin of MAC is mainly related to BRAF mutation,microsatellite instability,and the CpG island methylator phenotype *** addition,the poor prognosis of rectal MAC has been confirmed by various studies,and that of colonic MAC is still *** this review,we summarize the epidemiology,clinicopathological characteristics,molecular features,methods of diagnosis,and treatments of MAC in order to provide references for further fundamental and clinical research.

关键词： Mucinous adenocarcinoma Colorectal cancer Mucin Microsatellite instability Magnetic resonance imaging Treatment

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Stable carbon isotope composition and intrinsic water use efficiency in plants along an altitudinal gradient on the eastern slope of Yulong Snow Mountain, China

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Ecological Processes 2024年第2期13卷 218-230页

作者： Feng Jiang Tao Pu Zi-jing Xue Yan-Wei Ma Xiao-yi shi Fu-Xi shi College of Geography and Environmental Sciences Zhejiang Normal University Yulong Snow Mountain Glacier and Environment Observation and Research Station/State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of Forestry Jiangxi Agricultural University

Background Stable carbon isotope composition(δ13Cp) can be used to estimate the changes in intrinsic water use efficiency（iWUE） in plants,which helps us to better understand plants' response strategies to climate *** study focused on the variations in δ13Cpand iWUE for the different life-form plants（i.e.,herbs,shrubs,and trees）along an altitudinal gradient（3300,3600,3900,4100,4300,and 4500 m） on the eastern slope of Yulong Snow Mountain,southeastern margin of the Qinghai-Tibet *** response mechanisms of δ13Cpand iWUE for different life-form plants to altitude were thoroughly analyzed in this mountain *** The δ13Cpvalues of plants on the eastern slopes of Yulong Snow Mountain ranged from-30.4‰to-26.55‰,with a mean of-28.02‰,indicating a dominance of *** δ13Cpand iWUE values varied among different life-form plants in the order of herbs> shrubs> trees,particularly in 3600,3900,and 4300 ***δ13Cpand iWUE values for herbs and shrubs increased with altitude and were mainly controlled by air *** two parameters for trees exhibited a trend of initial decrease followed by an increase with *** 3900 m,the δ13Cpand iWUE values decreased with altitude,influenced by soil ***,above 3900 m,the two parameters increased with altitude,mainly regulated by air *** addition,iWUE was positively correlated with leaf P content but negatively correlated with leaf N:P ratio,especially for herbs and trees,suggesting that P plays a key role in modulating iWUE in this *** The diffe rentiated responses of water availability for different life-form plants to a higher altitudinal gradient are regulated by air temperature,soil moisture,and leaf P content in the Yulong Snow *** results provide valuable insights into understanding the wate r-carbon relationships in high-altitude ecosystems.

关键词： Stable carbon isotope Water use efficiency Altitude Life form Yulong Snow Mountain

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Angiotensin-converting enzyme gene I/D genotype affected metoprolol-induced reduction in 24-hour average heart rate

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Chinese Medical Journal 2010年第11期123卷 1382-1386页

作者： LIU Li-wei LIU Hong CHEN Guo-liang HUANG yi-ling HAN Lu-lu XU Zhi-min JIANG Xiong-jing LI yi-shi Key Laboratory of Clinical Trial Research in CardiovascularDrugs Ministry of Health Cardiovascular Institute and Fu WaiHospital Peking Union Medical College and Chinese Academy ofMedical Sciences Beijing 100037 China

Background Genetic factors can influence antihypertensive response to metoprolol, and many studies focused on the relationship between the genotype in β1-adrenergic receptor and blood pressure （BP）, little was known about the association of angiotensin-converting enzyme （ACE） genotype with the therapeutic result of metoprolol. The present study aimed to investigate whether the ACE gene insertion （I） / deletion （D） polymorphism is related to the response to metoprolol in Chinese Han hypertensive patients, Methods Ninety-six patients with essential hypertension received metoprolol （100 mg once daily） as monotherapy for 8 weeks. Twenty-four hours ambulatory blood pressure monitoring and dynamic electrocardiogram were performed before and after treatment. Genotyping analysis was performed using PCR. The association of the ACE gene I/D polymorphism with variations in BP and heart rate （HR） was observed after the 8-week treatment. Results The patients with ACE gene II polymorphism showed greater reduction in 24-hour average HR than those with ID or DD polymorphisms （P=0.045）, no effect of this genotype on the reduction in seating HR or in BP was observed. After adjusting for age, gender, body mass index, BP and HR at baseline, the ACE gene I/D polymorphism was still an independent predictor for variations in 24-hour average HR. Conclusions The II polymorphism in ACE gene could be a candidate predictor for greater reduction in 24-hour average HR in Chinese Han hypertensive patients treated by metoprolol. Greater benefits would be obtained by patients with II polymorphism from the treatment with metoprolol. Larger studies are warranted to validate this finding

关键词： essential hypertension, angiotensin-converting enzyme, polymorphism heart rate," metoprolol

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An uncertainty investigation for liner impedance eduction methods

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Chinese Journal of Aeronautics 2024年第3期37卷 49-59页

作者： Weihao shi Xiaodong jing School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Impedance eduction methods have been developed for decades to meet the increasing need for high-quality impedance data in the design and optimization of acoustic *** this end,it is important to fully investigate the uncertainty problem,to which only limited attention has been devoted so *** paper considers the possibility of acoustically-induced structural vibration as a nonnegligible uncertainty or error source in impedance eduction *** the frequency moves away from the resonant frequency,with the increase in the value of cavity reactance,the acoustic particle velocity inside liner orifices possibly decreases to the extent comparable to the vibration velocity of liner facing ***,the acoustically-induced vibration,although generally being weak except at the inherent structural frequencies,may considerably affect the impedance eduction results near the anti-resonant frequency where the liner has poor *** demonstrate the effect of structural vibration,the vibration velocity of liner facing sheet is estimated from the experimentally educed admittance of the liner samples whose orifices are sealed with ***,a three-dimensional numerical model is set up,in which normal particle velocity is introduced over the solid portion of liner facing sheet to imitate structural vibration,rather than directly solving the acoustic-structural coupling *** shown by the results,the vibration of liner facing sheet,whose velocity is as small as estimated by the experiment,can result in anomalous deviation of the educed impedance from the impedance model near the anti-resonant *** trend that the anomalous deviation varies with frequency is numerically captured.

关键词： Impedance eduction Uncertainty analysis Acoustically-induced structural vibration Anti-resonant frequency Perforated liner

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A stable staggered-grid finite-difference scheme for acoustic modeling beyond conventional stability limit

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Petroleum Science 2024年第1期21卷 182-194页

作者： jing-yi Xu Yang Liu National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China China University of Petroleum(Beijing) Karamay CampusKaramay 834000XinjiangChina

Staggered-grid finite-difference(SGFD)schemes have been widely used in acoustic wave modeling for geophysical *** improved methods are proposed to enhance the accuracy of numerical ***,these methods are inevitably limited by the maximum Courant-Friedrichs-Lewy(CFL)numbers,making them unstable when modeling with large time sampling intervals or small grid *** solve this problem,we extend a stable SGFD scheme by controlling SGFD dispersion relations and maximizing the maximum CFL ***,to improve modeling stability,we minimize the error between the FD dispersion relation and the exact relation in the given wave-number region,and make the FD dispersion approach a given function outside the given wave-number area,thus breaking the conventional limits of the maximum CFL ***,to obtain high modeling accuracy,we use the SGFD scheme based on the Remez algorithm to compute the FD *** addition,the hybrid absorbing boundary condition is adopted to suppress boundary reflections and we find a suitable weighting coefficient for the proposed *** derivation and numerical modeling demonstrate that the proposed scheme can maintain high accuracy in the modeling process and the value of the maximum CFL number of the proposed scheme can exceed that of the conventional SGFD scheme when adopting a small maximum effective wavenumber,indicating that the proposed scheme improves stability during the modeling.

关键词： Acoustic wave Staggered-grid finite-difference(SGFD) modeling Courant-friedrichs-lewy(CFL)number Stability

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A CT Image Segmentation Algorithm Based on Level Set Method

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Chinese Journal of Biomedical Engineering(English Edition) 2006年第2期15卷 47-52页

作者： QU jing-yi shi Hao-shan School of Electronic and Information Northwestern Polytechnical UniversityXi''an710072China School of Electronic and InformationNorthwestern Polytechnical UniversityXi''an710072China

Level Set methods are robust and efficient numerical tools for resolving curve evolution in image segmentation. This paper proposes a new image segmentation algorithm based on Mumford-Shah module. The method is used t... 详细信息

关键词： Medical image segmentation,Level set,Mumford-Shah model,Curve evolution

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