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肺气肿病灶的低形态计量学复杂性可预测慢性阻塞性肺疾病病人的生存

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国际医学放射学杂志 2019年第2期42卷 244-244页

作者： j.hwang Y.M.Oh M.Lee S.Choi j.B.Seo S.M.Lee 杨淑娟(译) 赵世华(校) Asan Institute for Life Sciences Asan Medical CenterSeoulKorea 不详

目的探讨肺部形态计量学复杂性能否作为预测慢性阻塞性肺疾病(COPD)病人生存率的新指标。方法对302例COPD病人在2005—2015年所接受的CT容积扫描和肺功能测试进行回顾性分析。

关键词：慢性阻塞性肺疾病形态计量学肺气肿

用扩散加权成像定性慢性肝病中钆塞酸增强MRI乏血供低信号结节

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国际医学放射学杂志 2015年第5期 471-471页

作者： j.hwang Y.K.Kim W.K.jeong D.Choi H.Rhim W.j.Lee 李燕菊 Department of Radiology and Center for Imaging Science Samsung Medical CenterSungkyunkwan University School of Medicine

摘要目的比较MR成像中DWI及T2WI特征表现,对于鉴别钆塞酸增强MR成像肝胆期检出的低信号结节中乏血供肝细胞肝癌(HCC)与发育不良结节的能力。材料与方法本回顾性研究经本单位伦理委员会批准并免除病人知情同意。研究对象为2011年3月—201... 详细信息

摘要目的比较MR成像中DWI及T2WI特征表现,对于鉴别钆塞酸增强MR成像肝胆期检出的低信号结节中乏血供肝细胞肝癌(HCC)与发育不良结节的能力。材料与方法本回顾性研究经本单位伦理委员会批准并免除病人知情同意。研究对象为2011年3月—2014年1月期间做过钆塞酸增强MRI检查并经病理确诊乏血供HCC(n=25)和(或)发育

关键词：结节发育不良 HCC 血供 MRI

Small Zeros of Additive Forms in Several Variables

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Acta Mathematica Sinica,English Series 1998年第1期14卷 57-66页

作者： j. S. hwang Institute of Mathematics Academia Sinica Taipei Taiwan 11529 China

Let f（X） be an additive form defined by f（X）=f（x1. x2,…,xs）=σ1α1x1k+σα2x2k+…+σsαsxsk, where αo≠0 is integer, i=1, 2,…, s. In 1979, Schmidt proved that if ε>0 then there is a large constant C（k, ε） such that for s≥C（k, ε） the equation f（X）=0 has a nontrivial integer solution in σ1. σ2,…σs, x1, x2…,xs satisfying σi=±1 and |xi|≤Aε, i=1, 2.…,s where A=max|ai|. Schmidt did not estimate this constant C（k. ε） since it would be extremely large. In this paper, we prove the following result: Theorem 1 If log A≤1/ε,then C（k,ε）≤max （2/ε,20）; if log A>1/ε,A is sufficiently larye and 1/2A≤5≤|ai|≤A,i=1. 2,…, s, then C（k,ε）≤c1c2p and if the last condition is omitted, then C（k. ε）≤[4/ε]c1c2,where c1={2k+1 for≤k≤11 [5k2log k] for k≥12, c2=100c1k22k+c12 and p=2[log 2c1/ε]. We note that the inequality in the first case is sharp but not in the second case.

关键词： Additive form Subset sums Small zeros

Fabrication and Properties of SiB6-B4C with Phenolic Resin as a Carbon Source

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journal of Materials Science & Technology 2008年第1期24卷 102-104页

作者： G. C.hwang j.Matsushita United Graduate School of Science and Engineering Tokai University 1117 Kitakaname Hiratsuka 259-12921 Japan

Si-B-C ceramic composites were synthesized using SiB-6,B-4C,and phenolic resin as a carbon source by pressureless sintering in an Ar ***,the Si-B-C ceramic composites were fabricated to determine their potential for applications as high hardness and high temperature *** X-ray diffraction patterns of sintered bodies of SiB-6-B-4C with carbonized phenolic resin can be seen that SiB-6 and C changed to B-4C and *** this study,it is obtained that carbonized phenolic resin is good addition material as a reaction material comparing to carbon powder at 1683 K for 1 h by pressureless sintering in an Ar atmosphere.

关键词： Silicon boride Boron carbide Phenolic resin

In vitro production of functional sperm in mice

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Asian journal of Andrology 2011年第6期13卷 791-792页

作者： Kathleen hwang Dolores j Lamb Scott Department of Urology Baylor College of Medicine Houston TX 77030 USA Scott Department of Urology and Molecular and Cellular Biology Baylor College of Medicine Houston TX 77030 USA Laboratory for Male Reproductive Research and Testing Baylor College of Medicine Houston TX 77030 USA

Spermatogenesis refers to the process by which the production and development of the spermatozoa （the mature male gamete of most sexually reproducing species） occurs. It is a complex, stepwise process of sperm development, taking more than a month depending upon the species involving three specific functional phases： spermatogonial proliferation, meiosis and metamorphosis.1 Investigators have been successful in recreating this process in some species of fish; however, this whole process has never been reproduced in vitro in mammals.

关键词： Spermatogenesis refers production the spermatozoa

Strain hardening rate dependency of deformation shape,strain distribution,and contact pressure during wire flat rolling

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journal of Iron and Steel Research International 2023年第3期30卷 475-486页

作者： joong-Ki hwang School of Mechatronics Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea

The effect of the strain hardening exponent(n)of a material on the changes in shape,strain inhomogeneity,and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with *** deformation behaviors of wires with various n values were systematically compared using finite element *** shape of the deformed wire was found to depend on the n value of the *** the contact width and lateral spreading of the wire decrease with increasing n,resulting in a large reduction in area with the n *** strain homogeneity of the wire increases with the n value of the *** improvement in the strain homogeneity with the n value is attributable to two factors:a lower strain concentration in the central region and a higher overall elongation as n *** addition,the average effective strain of the wire cross section decreases with the n value of a material during wire flat *** contact pressure distribution on the surface of the wire differs significantly depending on the n *** materials with a low n value,the contact pressure exhibits a higher value at the entry and edge zones of the contact *** contrast,materials with high n values exhibit a higher contact pressure at the exit *** behavior can be explained by the strain hardening behavior of the material during wire flat rolling.

关键词： Strain hardening exponent Wire flat rolling Shape change Strain inhomogeneity Contact pressure

Effect of drawing speed on microstructure distribution and drawability in twinning-induced plasticity steel during wire drawing

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journal of Iron and Steel Research International 2020年第5期27卷 577-587页

作者： joong-ki hwang School of Mechanical Engineering Tongmyong UniversityBusan 48520Republic of Korea

The effect of drawing speed on temperature rise and microstructure distribution in twinning-induced plasticity(TWIP)steel during wire drawing has been investigated to improve drawability for wire rod *** wire drawing process is performed at room temperature,heat is generated due to the plastic deformation and friction at the wire-die *** steel wires subjected to the low drawing speed(LD)of 0.5 m/min and the high drawing speed(HD)of 5.0 m/min were analyzed using the numerical simulation and electron backscatter diffraction ***,the specimens subjected to the HD had a higher drawability by about 18%compared to the LD,which is totally different from the general behavior of plain carbon pearlitic *** LD wire had uniform temperature distribution along the radial direction during wire *** contrast,the HD wire had a temperature gradient along the radial direction due to the higher frictional effect at surface:the minimum temperature of 58℃ at center area and the maximum temperature of 143 C at surface *** higher stacking fault energy of HD wire at the surface area due to the high temperature rise retarded twinning rate,resulting in the prevention of fast exhaustion in ductility in comparison with the LD wires since the earlier depletion of twins at surface area is known as the main reason for the fracture of TWIP steel during wire ***,HD process delayed the fracture strain of wire and increased the uniformity of microstructure and mechanical properties along the radial direction.

关键词： Twinning-induced plasticity steel Wire drawing Deformation twin Drawing speed Temperature rise

Material and structural instabilities of single-wall carbon nanotubes

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Acta Mechanica Sinica 2008年第3期24卷 285-288页

作者： j.Wu K.C.hwang j.Song Y.Huang FML Department of Engineering MechanicsTsinghua UniversityBeijing 100084China Department of Mechanical Science and Engineering University of Illinois1206 W.Green StreetUrbanaIL 61801USA Department of Civil and Environmental Engineering and Department of Mechanical Engineering Northwestern UniversityEvanstonIL 60208USA

The nonlinear atomistic interactions usually involve softening behavior. Instability resulting directly from this softening are called the material instability, while those unrelated to this softening are called the structural instability. We use the finite-deformation shell theory based on the interatomic potential to show that the tension instability of single-wall carbon nanotubes is the material instability, while the compression and torsion instabilities are structural instability.

关键词： Carbon nanotubes Instability

Correlation of microstructure with tensile behavior and properties of API X70 pipeline steels subjected to strain aging

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journal of Iron and Steel Research International 2020年第3期27卷 319-324页

作者： Sang-in Lee Byoungchul hwang Department of Materials Science and Engineering Seoul National University of Science and TechnologySeoul 01811Republic of Korea

Variations in tensile behavior and properties after pre-strain and thermal aging were differently affected by strain aging phenomenon dependent on *** increasing polygonal ferrite fraction,decrement in uniform elongation is increased,and the increment in yield-to-tensile ratio is slightly decreased after pre-strain and thermal ***,it can be concluded that the polygonal ferrite has contradictory effects on strain aging resistance although the polygonal ferrite still contributes to improvement of uniform elongation after strain aging.

关键词： Steel Microstructure Strain aging Deformability Pipeline