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Design of a low-alloy high-strength and high-toughness martensitic steel

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 733-740页

作者： yan-jun zhao Xue-ping Ren Wen-chao yang Yue Zang School of Materials Science and Engineering Guangxi University School of Materials Science and Engineering University of Science and Technology Beijing

To develop a high strength low alloy （HSLA） steel with high strength and high toughness, a series of martensitic steels were studied through alloying with various elements and thermodynamic simulation. The microstructure and mechanical properties of the designed steel were investigated by optical microscopy, scanning electron microscopy, tensile testing and Charpy impact test. The results show that cementite exists between 500℃ and 700℃, M7C3 exits below 720℃, and they are much lower than the austenitizing temperature of the designed steel. Furthermore, the Ti（C,N） precipitate exists until 1280℃, which refines the microstructure and increases the strength and toughness. The optimal alloying components are 0.19% C, 1.19% Si, 2.83% Mn, 1.24% Ni, and 0.049% Ti; the tensile strength and the V notch impact toughness of the designed steel are more than 1500 MPa and 100 J, respectively.

关键词： high strength steel martensitic steel alloy design thermodynamics alloying elements microstructuremechanical properties

CBN grain wear and its effects on material removal during grinding of FGH96 powder metallurgy superalloy

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Advances in Manufacturing 2023年第1期11卷 21-38页

作者： Ben-Kai Li Biao zhao Wen-Feng Ding Yu-Can Fu Chang-He Li Rong Wang yan-jun zhao National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing210016People’s Republic of China School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao266525ShandongPeople’s Republic of China Aecc Xi’an Aero-engine Ltd Xi’an710021People’s Republic of China State Key Laboratory of Superabrasives Zhengzhou Research Institute for Abrasive and GrindingZhengzhou450001People’s Republic of China

Grinding with cubic boron nitride(CBN)superabrasive is a widely used method of machining superalloy in aerospace ***,there are some issues,such as poor grinding quality and severe tool wear,in grinding of powder metallurgy superalloy *** addition,abrasive wheel wear is the significant factor that hinders the further application of CBN abrasive *** this case,the experiment of grinding FGH96 with single CBN abrasive grain using different parameters was carried *** wear characteristics of CBN abrasive grain were analyzed by experiment and *** material removal behavior affected by CBN abrasive wear was also studied by discussing the pile-up ratio during grinding *** shows that morphological characteristics of CBN abrasive grain and grinding infeed direction affect the CBN abrasive wear seriously by simulation *** wear,micro break,and macro fracture had an important impact on material removal ***,compared with the single cutting edge,higher pile-up ratio was obtained by multiple cutting edges,which reduced the removal efficiency of the ***,weakening multiple cutting edge grinding on abrasive grains in the industrial production,such as applying suitable dressing strategy,is an available method to improve the grinding quality and efficiency.

关键词： FGH96 powder metallurgy superalloy Single-grain grinding Cubic boron nitride(CBN)abrasive wear Material removal behavior

A novel way to synthesize Pb nanotapes in liquid ammonia

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Chinese Chemical Letters 2011年第8期22卷 993-996页

作者： Lei Sun Meng Lei Zhang Xiao jun Tao yan Bao zhao Key Laboratory for Special Functional Materials of Ministry of Education Henan University Kaifeng 475004 China

Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low *** process was template *** electron microscopy（TEM） observations and X-ray diffraction（XRD） characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 *** lengths up to several hundred nanometers, and exhibit cubic crystal structures.

关键词： Pb Nanotapes Chemical synthesis Liquid ammonia

The differential effects of prostate stromal cells derived from different zones on prostate cancer epithelial cells under the action of sex hormones

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Asian Journal of Andrology 2011年第6期13卷 798-805页

作者： Qi Jiang Bang-Min Han Fu-jun zhao yan Hong Shu-Jie Xia Department of Urology Shanghai First People＇s Hospital Institute of Urology Shanghai Jiao Tong University Shanghai 200080 China

It is well known that prostate cancer （PCa） occurs predominantly in the peripheral zone （PZ）, whereas benign prostatic hyperplasia （BPH） typically develops in the transition zone. To identify possible mechanisms underlying zonal differences, we compared the effects of prostate stromal cells derived from the peripheral zone （PZsc） and the transition zone （TZsc） on a PCa epithelial cell line （PC3） in the presence of sex hormones. First, we observed that androgen receptor （AR） mRNA was more highly expressed in PZsc than TZsc when the cells were treated with dihydrotestosterone （DHT） and β-oestradiol （E2）（P〈0.05）. By ELISA, we looked for differences in the secretion of peptide growth factors from PZsc and TZsc. We found that keratinocyte growth factor （KGF） secretion increased with increasing concentrations of DHT （P〉0.01） and was higher in PZsc than TZsc. Under treatment with DHT plus E2, PZsc secreted more transforming growth factor-β1 （TGF-β1） than TZsc, but this pattern was reversed when the cells were treated with E2 only. With increasing concentrations of DHT, insulin-like growth factor-1 （IGF-1） secretion increased in PZsc but decreased in TZsc. To further characterize the effects of PZsc and TZsc on PC3 cells, we developed a coculture model and performed MTT assays, Western blot analysis and real-time RT-PCR. We found that PZsc promoted PC3 cell proliferation and progression better than TZsc, particularly when treated with 10 nmoll^- 1 DHT plus 10 nmoll^-1 E2. In conclusion, our data suggest that PZsc may have a greater capacity to induce PCa development and progression than TZsc via growth factors regulated by sex hormones. These findings provide possible mechanisms underlying zonal differences in prostate diseases, which may aid the search for novel therapeutic targets for PCa.

关键词： androgen growth factor oestrogen prostate cancer stromal cell

Scoring system for poor limb perfusion after limb fracture in children

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World Journal of Clinical Cases 2020年第23期8卷 5926-5934页

作者： Ting Zhu Yu Shi Qun Yu yan-jun zhao Wen Dai yan Chen Shun-Sheng Zhang Department of Pediatric Orthopedics Xinhua Hospital Affiliated to Shanghai Jiaotong University School of MedicineShanghai 200092China Zunran Hospital Shanghai 200366China

BACKGROUND Assessment of the vascular status following limb fracture in children is important to evaluate the risk of compartment syndrome,which is an emergency *** To establish a simple and efficient grading scale of limb perfusion in children undergoing surgery for limb *** This retrospective study included pediatric patients with a limb fracture and postoperative plaster fixation who were admitted at The Department of Pediatric Orthopedics of Xinhua Hospital between February 2017 and August *** outcome was poor limb perfusion,which is defined as the postoperative use of *** children were divided into two groups:The normal perfusion group and the poor perfusion *** risk factors have been selected by univariable analyses to establish the Grading Scale for Vascular *** A total of 161 patients were included in the study:85 in the normal perfusion group and 76 in the poor perfusion *** were no significant differences in age,sex,body mass index,ethnicity,cause of fracture,fixation,or site of fracture between the two *** surgery,the skin temperature(P=0.048)and skin color(P<0.001)of the affected limb were significantly different between the two *** relative risk and 95%confidence interval for skin temperature of the affected limb,skin color,and range of motion of the affected limb are 2.18(1.84-2.59),2.89(2.28-3.66),and 2.16(1.83-2.56),*** grading scale was established based on those three factors(score range:0-3 points).Forty-one patients(32.5%)with score 0 had poor limb perfusion;all patients with scores 1(n=32)and 2(n=3)had poor limb perfusion(both 100%).CONCLUSION In children undergoing surgery for limb fracture,a higher Grading Scale for Vascular Status score is associated with a higher occurrence of poor limb perfusion.A prospective study is required for validation.

关键词： Children Fractures Compartment syndromes Evaluation Open fracture reduction Retrospective study

Catalytic behavior of Mo-Bi-Fe-Co-K-M-O(M=Ce,Gd,CeGd)catalysts for selective oxidation of isobutene

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Journal of Rare Earths 2024年第1期42卷 84-93,I0003页

作者： Qinghui Li Huahua zhao Jian yang jun zhao Liang yan Huanling Song Lingjun Chou State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China University of Chinese Academy of Sciences Beijing100049China

The further improvement of methacrolein(MAL)selectivity from isobutene(IB)oxidation is crucial and *** this study,based on the typical Mo-Bi-Fe-Co-K-O mixed metal oxide,the rare earth element Gd-doped,Ce-doped and CeGd co-doped catalysts were prepared by co-precipitation strategy to increase the selectivity of MAL from 47.9%to 49.8%,64.2% and 68.6%,*** order to elucidate in-depth the promoting effect of Ce and/or Gd,various characterizations were utilized including X-ray diffraction patterns(XRD),Raman,X-ray fluorescence spectrometry(XRF),X-ray photoelectron spectroscopy(XPS),O_(2)-temperature programmed desorption(O_(2)-TPD),H2-temperature programmed reduction(H2-TPR),CO_(2)-temperature programmed desorption(CO_(2)-TPD),IB-temperature programmed desorption(i-C4-TPD)and in-situ IB-Fourier transform infrared spectroscopy(IB-FTIR).Both Ce and Gd finely regulate the bulk and surface structure of the catalyst,thus altering the redox ability,oxygen mobility and storage ability and *** with Ce,Gd addition slightly regulates the variation of Co^(2+)/Co^(3+)redox couples,greatly enhances the interaction among the components on the catalyst,thus only increases the content of surface oxygen species and has little effect on their *** Cecontaining catalyst performs stronger oxygen storage and migration ability,thus leading to the overproduction of surface Odefectspecies,which are proposed to be the active sites for the production of MAL and *** CeGd co-doped catalyst possesses the proper content of surface Odefectspecies,thus exhibits much higher MAL ***,the promoting mechanism of Ce and/or Gd over IB oxidation is ***,this work is helpful for understanding the influence of rare earth elements on the structure of mixed metal oxides and the olefin selective oxidation reaction.

关键词： Mixed metal oxide catalyst Rare earth element Isobutene Selective oxidation Methacrolein

Function of c-Fos-like and c-jun-like Proteins on Trichostatin A-induced G2/M Arrest in Physarum polycephalum

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Acta Biochimica et Biophysica Sinica 2005年第11期37卷 767-772页

作者： Xiao-Xue LI jun LU yan-Mei zhao Bai-Qu HUANG Institute of Genetics and Cytology,Northeast Normal University,Changchun 130024,China Institute of Genetics and Cytology Northeast Normal UniversityChangchun 130024 China

The homologs of transcription factors c-Fos and c-jun have been detected in slime moldPhysarum polycephalum during progression of the synchronous cell *** we demonstrated that c-Fos-like and c-jun-like proteins participated in G2/M transition by the regulation of the level of Cyclin B1protein in *** study of antibody neutralization revealed that interruption of the functions ofc-Fos-like and c-jun-like proteins resulted in G2/M transition arrest,implicating their functional roles in cellcycle *** G2/M transition was blocked by histone deacetylase inhibitor trichostatin A,changes inc-Fos- and c-jun-like protein levels,and hyperacetylation of c-jun-like protein,were *** datasuggest that in ***,c-Fos- and c-jun-like proteins may be the key factors in the regulation ofhistone acetylation-related G2/M transition,involving the coordinated expression and hyperacetylation ofthese proteins.

关键词： c-Fos-like protein c-jun-like protein trichostatin A G2/M transition Physarum polycephalum

Erythropoietin reduces apoptosis of brain tissue cells in rats after cerebral ischemia/reperfusion injury:a characteristic analysis using magnetic resonance imaging

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Neural Regeneration Research 2016年第9期11卷 1450-1455页

作者： Chun-juan Jiang Zhong-juan Wang yan-jun zhao Zhui-yang Zhang Jing-jing Tao Jian-yong Ma Department of Radiology Wuxi Second People's Hospital Affiliated to Nanjing Medical University

Some in vitro experiments have shown that erythropoietin （EPO） increases resistance to apoptosis and facilitates neuronal survival follow- ing cerebral ischemia. However, results from in vivo studies are rarely reported. Perfusion-weighted imaging （PWI） and diffusion-weighted imaging （DWI） have been applied successfully to distinguish acute cerebral ischemic necrosis and penumbra in living animals; therefore, we hypothesized that PWI and DWI could be used to provide imaging evidence in vivo for the conclusion that EPO could reduce apoptosis in brain areas injured by cerebral ischemia/reperfusion. To validate this hypothesis, we established a rat model of focal cerebral ischemia/ reperfusion injury, and treated with intra-cerebroventricular injection of EPO （5,000 U/kg） 20 minutes before injury. Brain tissue in the ischemic injury zone was sampled using MRI-guided localization. The relative area of abnormal tissue, changes in PWI and DWI in the ischemic injury zone, and the number of apoptotic cells based on TdT-mediated dUTP-biotin nick end-labeling （TUNEL） were assessed. Our findings demonstrate that EPO reduces the relative area of abnormally high signal in PWI and DWI, increases cerebral blood volume, and decreases the number of apoptotic cells positive for TUNEL in the area injured by cerebral ischemia/reperfusion. The experiment pro- vides imaging evidence in vivo for EPO treating cerebral ischemia/reperfusion injury.

关键词： nerve regeneration nerve protection cerebral ischemia/reperfusion erythropoietin magnetic resonance imaging diffusion-weightedimaging apparent diffusion coefficient perfusion-weighted imaging cerebral blood volume mean transit time apoptosis neural regeneration

A buffer overflow detection and defense method based on RiSC-V instruction set extension

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Cybersecurity 2024年第2期7卷 28-43页

作者： Chang Liu yan-jun Wu Jing-Zheng Wu Chen zhao Intelligent Software Research Center Institute of SoftwareChinese Academy of SciencesBejingChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijingChina

Buffer overflow poses a serious threat to the memory security of modern operating *** overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow *** makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer *** example,No eXecute(NX for short)is a memory management technology commonly used in Harvard *** can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control ***,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,***,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is *** in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow *** the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security ***,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in *** to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system

关键词： RISc-V Operating system security Buffer overflow Control flow hijacking Nx bit Xibop