J. T. Liu
,
H.B. Chang
,
R.H. Wu
,
T. Y. Hsu(Xu Zuyao) and X.R. Ruan( 1)Department of Plasticity Technology
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China 2)School of Materials Science and Engineering
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)
金属学报(英文版)
The hot deformation behavior of TI (18W-4Cr-1V) high-speed steel was investigated by means of continuous compression tests performed on Gleeble 1500 thermomechan- ical simulator in a wide range of tempemtures (950℃-1150℃) with strain rotes of 0.001s-1-10s-1 and true strains of 0-0. 7. The flow stress at the above hot defor- mation conditions is predicted by using BP artificial neural network. The architecture of network includes there are three input parameters:strain rate,temperature T and true strain , and just one output parameter, the flow stress ,2 hidden layers are adopted, the first hidden layer includes 9 neurons and second 10 negroes. It has been verified that BP artificial neural network with 3-9-10-1 architecture can predict flow stress of high-speed steel during hot deformation very well. Compared with the prediction method of flow stress by using Zaped-Holloman parumeter and hyperbolic sine stress function, the prediction method by using BP artificial neurul network has higher efficiency and accuracy.
关键词:
T1 high-speed steel
,
null
,
null
,
null
,
null
李铂
,
周建江
,
夏伟杰
,
吴连慧
液晶与显示
doi:10.3788/YJYXS20142904.0605
直线是机载座舱显示画面中最基本的图元,其显示质量对于整个画面的显示效果影响较大,尤其是小角度下直线显示的“麻花”现象一直是影响显示效果的关键问题之一.为了提高小角度下直线的显示效果,本文提出了一种基于Wu算法的亮度渐变改进算法.该算法通过渐进地展现直线从轴方向上的亮度变化过程,减少亮度畸变,有效地改进了显示效果.通过Matlab仿真和FPGA实现,验证了该算法反走样后的小角度直线显示效果明显优于其他算法,而且结合中点画线法后,绘制时间与Wu算法相当.同时该算法还可改善大角度直线和圆弧的显示效果,消除了大角度直线的边缘锯齿,解决了圆弧在小角度部分的虚化问题.因此本文算法可用于对实时性和显示效果要求高的机载座舱显示系统,以缓解飞行员的视觉疲劳.
关键词:
座舱显示
,
反走样
,
改进Wu算法
,
小角度
,
FPGA实现
陶明
,
熊伟
,
陈华
,
李贤均
催化学报
合成了(R,R)-1,2-二苯基乙二胺((R,R)-DPEN)、钌和三苯基膦的三元配合物RuCl2[P(C6H5)3]2-(R,R)-DPEN,并将其用于萘乙酮的不对称加氢反应.考察了碱/催化剂的摩尔比、反应温度和氢气压力等对催化活性和对映选择性的影响.结果表明,多种因素对反应的转化率和对映选择性均有影响.在萘乙酮:(CH3)3COK:催化剂摩尔比为50 000:450:1,氢气压力为4 MPa,反应温度为25℃的条件下,反应16 h时,萘乙酮生成α-萘乙醇的产率和对映选择性分别达到了100%和83%.
关键词:
钌膦配合物
,
手性二胺
,
萘乙酮
,
不对称催化加氢
,
α-萘乙醇
,
对映选择性
秦鹏
,
李萍
,
侯天宇
,
赵杰
,
李廷举
材料工程
doi:10.11868/j.issn.1001-4381.2016.11.015
基于对影响非线超声性检测因素的探讨，考察了应用非线性检测无损评价H R3C烟侧腐蚀的可行性。结果表明：脉冲激励串个数 n≤2df／c ，加汉宁窗有助于降低系统干扰，此外，样品表面粗糙度对非线性系数β产生显著的影响。随腐蚀时间的延长，非线性系数呈现阶段性的递增趋势。腐蚀初期（腐蚀时间在50h以内），非线性系数增幅不足20％；然而，腐蚀至150h ，非线性系数显著增加；相对于未腐蚀样品，腐蚀200h时的非线性系数增幅达260％。非线性系数的单调变化与腐蚀损伤的加剧相一致，因此，应用超声非线性无损评价 H R3C的烟侧腐蚀是可行的。
关键词:
非线性超声检测
,
非线性系数
,
烟侧腐蚀
杨敏
,
常海萍
,
毛军逵
工程热物理学报
本文实验研究了离心力场下细微封闭循环通道中,以H2O和氟利昂R12为热驱动介质的热驱动流动规律和换热特性,重点分析了热驱动换热技果随Ra数Ro数的变化规律以及冷却效果.实验结果表明:在热流密度和旋转速度相同的条件下,采用介质R12可以获得较高的半均换热系数,冷却效果也优于以H2O为介质的冷却效果.最后建立了两种介质条件下相应的准则关系式.
关键词:
热驱动
,
热驱动介质
,
细微通道
,
旋转
,
换热系数
吴连慧
,
周建江
,
夏伟杰
,
陈雅雯
液晶与显示
doi:10.3788/YJYXS20153001.0163
对于光栅化的三角形,其边缘存在明显的锯齿现象,因此需要进行反走样处理.基于Wu直线反走样算法的思想,考虑了水平直线外侧直接添加插值点的算法和三角形三边外侧反走样的算法.综合两者的优点,在绘制光栅化的三角形的同时,边缘叠加Wu反走样直线,并考虑背景像素灰度值的作用.结果表明,改进的三角形光栅化的边缘反走样算法有效提高了三角形光栅化后边缘的显示效果,该算法计算量小,便于FPGA实现,可用于对图形显示质量要求很高的机载显示系统.
关键词:
反走样
,
Wu算法
,
光栅化
,
FPGA
刘欢
,
严凯
,
晏井利
,
薛烽
,
孙甲鹏
,
江静华
,
马爱斌
中国有色金属学报(英文版)
doi:10.1016/S1003-6326(17)60007-4
为了揭示14H相的形成机理，制备并研究了18R LPSO单相Mg?Y?Zn(简称S18)合金经773 K退火100 h的显微组织演变。结果表明：铸态S18合金主要由18R相组成(其体积分数高于93%)，并含有少量的W相和α-Mg相。退火时，S18合金中的18R相保持稳定，未转变成14H LPSO结构。然而，在α-Mg相内部形成了14H层片相，其尺寸和体积分数随着退火时间的延长不断增大。TEM分析表明，14H相在α-Mg内基面堆垛层错区域独立形核。14H层片的增厚生长是界面控制过程，与基面台阶的形成密切联系。而14H层片的伸长生长属于扩散控制，与溶质元素的扩散有关。该18R单相合金中14H相的形成机理可通过反应式α-Mg'→α-Mg +14H表示。
关键词:
Mg-Y-Zn合金
,
18R LPSO相
,
14H LPSO相
,
高温退火
,
显微组织演变
胡跃鑫
,
冯玉林
,
姜伟
应用化学
doi:10.3724/SP.J.1095.2011.00521
采用不同尺寸的碳酸钙粒子增韧高密度聚乙烯,研究了不同温度下共混体系的临界粒子间距与碳酸钙粒子尺寸和含量之间的关系,确定了温度是Wu氏增韧理论临界粒子间判据适用性的重要影响因素.结果表明,在17℃下,临界粒子间距与碳酸钙粒子的尺寸和含量无关,该条件下Wu氏增韧理论临界粒子间距判据是适用的;而随着温度的升高,发现临界粒子间距依赖于碳酸钙粒子的尺寸,表明高温条件下,Wu氏增韧理论临界粒子间距判据不再适用.
关键词:
聚合物增韧
,
粒子间距
,
脆韧转变
Communications in Theoretical Physics
The unified theoretical calculation of thermal shifts (TS) of R-1 and R-2 lines and thermal broadenings (TB) of R, R' and B lines for ruby was carried out for the first time. The calculated results are in very good agreement with a great number of experimental data. Especially by using quantum theory and taking into account all the admixtures of wavefunctions within d(3) electronic configuration, all the Gamma M in electron-phonon interaction (EPI), the electronic energy spectrum and lattice-vibration Spectrum, the very important contributions to TS and TB from single-phonon direct process were theoretically calculated in detail. The microscopic essentials of various contributions are revealed, and the mistakes in previous work are remedied.
关键词:
diamond anvil cell;pressure measurement;spectroscopy;temperatures
Journal of Applied Physics
Samples of R2Fe17C(y)N(x) (R = Y, Sm, Er, Tm) were prepared by arc melting appropriate amount of R, Fe, and C, vacuum annealing at 1373 K and finally annealing at 740 K in nitrogen for 10 h. The magnetic properties of these compounds were investigated by means of ac initial susceptibility, magnetization measurements, and x-ray diffraction. The thermal stability of the nitride phase was studied by differential scanning calorimetry. It was found that, when heated above 600 K, R2Fe17C(y)N(x) irreversibly decomposes N which is irrespective of the carbon concentration and rare-earth element. The Curie temperatures of R2Fe17C(y)N(x) are independent of the carbon concentration and are approximately 400 K higher than those of the corresponding pure R2Fe17 compounds. However, the Curie temperatures cannot be correlated to the composition x of the initial R2Fe17C(y)N(x) compounds at room temperature because some N was lost during the heating to T(c). In the Er and Tm compounds spin reorientation transitions were found, marking the change of the easy magnetization direction from the c axis to the basal plane with increasing temperature. The Tm compounds show an additional magnetic transition at low temperatures (below 40 K). A coexistence of the hexagonal and the rhombohedral structural modifications was found in Er2Fe17C(y)N(x) when y < 1.5, characterized by two different spin reorientation temperatures. The anisotropy fields of Sm2Fe17C(y)N(x) are higher than that of Sm2Fe17N(x). Indications of a magnetic phase transition were found also in Sm2Fe17C0.7N(x) and Sm2Fe17C0.9N(x).
关键词:
magnetocrystalline anisotropy;carbides;alloys
