期刊文献+
共找到219篇文章
< 1 2 11 >
每页显示 20 50 100
Effect of ω-3 Polyunsaturated Fatty Acid on Toll-like Receptors in Patients with Severe Multiple Trauma 被引量:2
1
作者 易呈志 白祥军 +4 位作者 陈继革 陈驾君 李剑 刘鹏 廖忆刘 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2011年第4期504-508,共5页
This study examined the effects of ω-3 polyunsaturated fatty acid(ω-3PUFA) on the expression of toll-like receptor 2(TLR2),toll-like receptor 4(TLR4) and some related inflammatory factors in peripheral blood m... This study examined the effects of ω-3 polyunsaturated fatty acid(ω-3PUFA) on the expression of toll-like receptor 2(TLR2),toll-like receptor 4(TLR4) and some related inflammatory factors in peripheral blood mononuclear cells(PBMCs) of patients with early-stage severe multiple trauma.Thirty-two patients who were admitted to the Department of Traumatic Surgery,Tongji Hospital(Wuhan,China) between May 2010 and November 2010,and diagnosed as having severe multiple trauma with a injury severity score(ISS) no less than 16,were enrolled in the study and divided into two groups at random(n=16 in each):ω-3PUFA group and control group in which routine parenteral nutrition supplemented with ω-3PUFA or not was administered to the patients in two groups for consecutive 7 days.Peripheral blood from these patients was collected within 2 h of admission(day 0),and 1,3,5 and 7 days after the nutritional support.PBMCs were isolated and used for detection of the mRNA and protein expression of TLR2 and TLR4 by using real-time PCR and flow cytometry respectively,the levels of NF-κB by quantum dots-based immunofluorescence assay,the levels of TNF-α,IL-2,IL-6 and COX-2 by ELISA,respectively.The results showed that the mRNA and protein expression of TLR2 and TLR4 in PBMCs was significantly lower in ω-3PUFA group than in control group 5 and 7 days after nutrition support(both P0.05).The levels of TNF-α,IL-2,IL-6 and COX-2 were found to be substantially decreased in PBMCs in ω-3PUFA group as compared with control group at 5th and 7th day(P0.05 for all).It was concluded that ω-3PUFA can remarkably decrease the expression of TLR2,TLR4 and some related inflammatory factors in NF-κB signaling pathway in PBMCs of patients with severe multiple trauma,which suggests that ω-3PUFA may suppress the excessive inflammatory response meditated by the TLRs/NF-κB signaling pathway. 展开更多
关键词 ω-3 polyunsaturated fatty acid severe multiple trauma toll-like receptor 2 toll-like receptor 4
下载PDF
Multiple cycles of magnetic activity in the Sun and Sun-like stars and their evolution
2
作者 Elena Aleksandrovna Bruevich Vasily Vladimirovich Bruevich Boris Pavlovich Artamonov 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第7期21-36,共16页
The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data... The wavelet transform method for high-quality time-frequency analysis is applied to sets of observations of relative sunspot numbers and stellar chromosphere fluxes of 10 Sun-like stars. Wavelet analysis of solar data shows that in a certain interval of time there are several cycles of activity with pe- riods of duration which vary considerably from each other: from quasi-biennial cycles to lO0-yr cycles. Cyclic activity was detected in almost all Sun-like stars that we examined, even those that previously were not considered as stars with cyclic activity according to analysis using a Scargle periodogram. The durations of solar and stellar cycles significantly change during the observation period. 展开更多
关键词 SUN activity - multiple cycles - Sun-like stars ACTIVITY
下载PDF
Multiple Regression Analysis of Influencing Factors on Yield of New Sugarcane Variety Yuetang 03-373
3
作者 Fangyin PAN Fuye LIU +1 位作者 Mingfu WEN Qingwen LUO 《Asian Agricultural Research》 2020年第5期47-49,共3页
[Objectives]The purpose of this study was to provide reference for cultivation and promotion of a new sugarcane variety Yuetang 03-373,on the basis of analyzing and summarizing the characters of the variety.[Methods]C... [Objectives]The purpose of this study was to provide reference for cultivation and promotion of a new sugarcane variety Yuetang 03-373,on the basis of analyzing and summarizing the characters of the variety.[Methods]Correlation,multiple regression and path analyses were performed for the yield and yield components of Yuetang 03-373.[Results]Correlation analysis shows that cane yield was significantly correlated with millable stalk number,stalk length and stalk diameter,and among them,the correlation with millable stalk number was the strongest.Multiple regression and path analyses show that millable stalk number contributed the most to cane yield,followed by stalk length,and stalk diameter contributed the least.The regression equation of cane yield against the three yield components was y=-2.8713+1.5497x1+5.8990x2-395.4294x3(R=0.9672**).[Conclusions]Millable stalk number and stalk length were the important and major factors for high yield of Yuetang 03-373,indicating that Yuetang 03-373 is a sugarcane variety of millable stalk type.In cultivation,full play should be given to the advantage of Yuetang 03-373 in millable stalk number,as well as stalk length(plant height),in order to achieve the purpose of increasing yield. 展开更多
关键词 Yuetang 03-373 Yield traits Correlation analysis multiple regression analysis
下载PDF
Multiple Ionization of Argon Induced by Carbon Ions at 20-500 keV/u Energies
4
作者 牛书通 刘文彪 +6 位作者 杨爱香 韩承志 胡伟 温志文 高志民 邵剑雄 陈熙萌 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第7期50-53,共4页
We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw+ (q= 1-3) ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, an... We measure the multiple ionization cross-section ratios Rk1 of Ar impacted by Cw+ (q= 1-3) ions in the energy range of 20-500 keV/u. The measured ratios Rkl increase with the projectile energy at lower energies, and reach the maximum at energies of 50-150 keV/u, then decrease for higher energies, We also use the classical over barrier ionization model to calculate the ratios Rk1, and the calculation results are in good agreement with the data, which suggest that the multiple ionization process is described by the sequential over-barrier ionization process, 展开更多
关键词 In multiple Ionization of Argon Induced by Carbon Ions at 20-500 keV/u Energies
下载PDF
Rare Aggressive Form of Multiple Myeloma with Diffuse Osteosclerosis and Elevated CA 15-3 Levels
5
作者 Dally Najib Daniel Talmud +2 位作者 Saher Srour Rola Khamisy-Farah Raymond Farah 《Open Journal of Internal Medicine》 2016年第1期11-14,共4页
We report the case of a 56-year-old female who had recently been examined for back and epigastric pain, and was diagnosed in the internal medicine ward as having an aggressive rare form of multiple myeloma with diffus... We report the case of a 56-year-old female who had recently been examined for back and epigastric pain, and was diagnosed in the internal medicine ward as having an aggressive rare form of multiple myeloma with diffuse osteoblastic bone lesions. She also had high levels of breast tumor marker (CA 15-3), severe tumor lysis syndrome, and pleural and central nervous system involvement. A few cases of multiple myeloma with diffuse osteosclerosis that are not part of POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changeshave) have been described. None of these cases were as aggressive as our case. To our knowledge it is the first report describing an elevation in CA 15-3 in conjunction with multiple myeloma. 展开更多
关键词 multiple Myeloma OSTEOSCLEROSIS CA 15-3 Pleural Effusion
下载PDF
Prediction of cavity growth rate during underground coal gasification using multiple regression analysis 被引量:8
6
作者 Mehdi Najafi Seyed Mohammad Esmaiel Jalali +1 位作者 Reza KhaloKakaie Farrokh Forouhandeh 《International Journal of Coal Science & Technology》 EI 2015年第4期318-324,共7页
During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by... During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by controllable (operation pressure, gasification time, geometry of UCG panel) and uncontrollable (coal seam properties) factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 1 l UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR. 展开更多
关键词 Underground coal gasification (UCG) - Cavity growth rate . multiple regression analysis ~ Empirical model
下载PDF
自动固相微萃取(SPM E)GC-MS、GC-MS-MS法检测环境水中有机磷杀虫剂的研究 被引量:6
7
作者 魏立青 郭杰 +1 位作者 蒋华宇 种法运 《分析测试学报》 CAS CSCD 北大核心 2004年第z1期226-230,共5页
  固相微萃取(solid-phase microextraction,SPME)是20世纪90年代发展起来的一种样品前处理技术,与传统的液-液提取、液-固提取相比,SPME更适用于提取、浓缩液态或气态的挥发性和半挥发性物质,SPME技术可将采样、萃取、浓缩和样本引...   固相微萃取(solid-phase microextraction,SPME)是20世纪90年代发展起来的一种样品前处理技术,与传统的液-液提取、液-固提取相比,SPME更适用于提取、浓缩液态或气态的挥发性和半挥发性物质,SPME技术可将采样、萃取、浓缩和样本引入集中于一个步骤完成,尤其随着自动SPME与GC-MS等联用技术的日益完善,使SPME技术优点得到更充分的发挥.…… 展开更多
关键词 Organophosphate insecticides Auto Solid-phase microextraction(auto-SPME) Gas chromatographymass spectrometry(GC - MS) Gas chromatography - multiple mass spectrometry(GC - MS - MS)
下载PDF
基于变长聚类的多敏感属性概率k-匿名算法 被引量:4
8
作者 唐印浒 钟诚 《计算机工程与设计》 CSCD 北大核心 2014年第8期2660-2665,共6页
充分考虑记录之间的距离以及记录本身权重值对聚类种子选择的影响,建立聚类种子选取模型,以获得更好的聚类结果。提出基于改进变长聚类的多敏感属性概率k-匿名算法,以提高数据可用性;提出融合k-means与改进变长聚类算法的概率k-匿名算法... 充分考虑记录之间的距离以及记录本身权重值对聚类种子选择的影响,建立聚类种子选取模型,以获得更好的聚类结果。提出基于改进变长聚类的多敏感属性概率k-匿名算法,以提高数据可用性;提出融合k-means与改进变长聚类算法的概率k-匿名算法,采用多线程并行技术,在不降低信息损失度与匿名质量的前提下,提升处理大数据集的效率。实验结果表明,所提算法效率较高,其生成的匿名数据集具有较好的数据可用性。 展开更多
关键词 数据发布 多敏感属性 概率κ-匿名 变长聚类 并行线程
下载PDF
液压支架立柱导向套大螺距梯形螺纹加工的研究与实践
9
作者 杨贵 欧艳梅 《煤矿机械》 2024年第3期99-102,共4页
对于大螺距的梯形螺纹加工中一般利用宏程序指令编程,但在编程时计算量比较大,容易出错,通过反复实践和研究,多重螺纹切削循环G76指令由于编程指令简单明了、加工效率高,在企业生产线应用比较广泛。利用G76指令进行切削量恒定的错齿切削... 对于大螺距的梯形螺纹加工中一般利用宏程序指令编程,但在编程时计算量比较大,容易出错,通过反复实践和研究,多重螺纹切削循环G76指令由于编程指令简单明了、加工效率高,在企业生产线应用比较广泛。利用G76指令进行切削量恒定的错齿切削,解决了大螺距梯形螺纹加工中出现的崩刃、扎刀问题,顺利地完成了加工任务。 展开更多
关键词 多重螺纹切削循环G76 宏程序 大螺距 梯形螺纹
下载PDF
基于多项式加减速的多头螺纹磨削算法研究
10
作者 张威 吴双峰 +1 位作者 贺明茹 邢虎 《机电工程》 CAS 北大核心 2024年第11期2050-2059,共10页
对多头螺纹进行磨削加工时,为了实现砂轮与切入点对齐,砂轮需要回到零点,并在零点等待一转信号和主轴转过偏转角度,而等待固定的信号会导致插补效率降低。针对这一问题,设计了一种基于混合非对称多项式加减速控制算法的多头螺纹快速分... 对多头螺纹进行磨削加工时,为了实现砂轮与切入点对齐,砂轮需要回到零点,并在零点等待一转信号和主轴转过偏转角度,而等待固定的信号会导致插补效率降低。针对这一问题,设计了一种基于混合非对称多项式加减速控制算法的多头螺纹快速分头算法。首先,分析了螺纹分头原理和砂轮切入方法,提取了切入点选择特征;然后,采用分区建立了插补时间规划模型,根据插补时间规划方法和砂轮切入点选择特征,建立了砂轮与每个切入点对齐的脉冲时间变化模型;之后,根据五次速度曲线加减速控制算法和三次速度曲线加减速控制算法的基本原理,设计了混合非对称多项式加减速控制算法模型,建立了参数控制模型及快退区目标速度预测模型;最后,采用MATLAB仿真的方法,验证了多头螺纹快速分头算法的正确性和有效性。研究结果表明:在工况1、工况2条件下(螺纹头数分别为20、25,其他条件相同),顺序切入和对称切入的加工效率分别提高了12.98%、0.67%,根据工况参数可以确定加工效率最高的砂轮切入方法;采用变加减速控制的方法,在快退区减速段可以实现±4 ms的容差控制目标,降低了砂轮与切入点对齐算法的容差压力;采用混合非对称多项式加减速控制算法,可以对多头螺纹快速分头插补和加加速度进行柔性控制,以提高螺纹分头的效率。 展开更多
关键词 多头螺纹分头算法 五次速度曲线 三次速度曲线 插补时间规划 螺纹切入点 混合非对称加减速控制算法 参数控制模型
下载PDF
多重吸附同步净化-气相色谱-质谱联用法测定水产品中痕量的二甲苯麝香和酮麝香 被引量:5
11
作者 丁立平 蔡春平 +2 位作者 林永辉 吴文凡 方祥 《色谱》 CAS CSCD 北大核心 2014年第3期309-313,共5页
为了考察水产品中二甲苯麝香和酮麝香的残留量,建立了水产品中痕量二甲苯麝香和酮麝香测定的多重吸附同步净化(MASP)-气相色谱-质谱联用法(GC-MS)。以乙腈高速匀浆提取样品,应用 MASP 方法对样品同时进行提取、盐析和净化,并采用... 为了考察水产品中二甲苯麝香和酮麝香的残留量,建立了水产品中痕量二甲苯麝香和酮麝香测定的多重吸附同步净化(MASP)-气相色谱-质谱联用法(GC-MS)。以乙腈高速匀浆提取样品,应用 MASP 方法对样品同时进行提取、盐析和净化,并采用 GC-MS 在选择离子监测( SIM)模式下测定水产品中的痕量二甲苯麝香和酮麝香,以基质匹配标准溶液外标法定量。选用 DB-5 MS 石英毛细管柱(30 m×0.25 mm×0.25μm),采用电子轰击电离源,二甲苯麝香的选择监测离子为 m / z 282、297、265,酮麝香为 m / z 279、294、191。结果表明:在优化条件下,二甲苯麝香和酮麝香在1~100μg / kg 范围内线性良好,相关系数不低于0.999,检出限(S / N =3)为0.30μg / kg。明虾、花蛤和鳗鱼空白样品中1.0、2.0、10.0μg / kg 3个添加水平下二甲苯麝香和酮麝香的加标回收率为79%~104%,相对标准偏差(RSD)为1.6%~13.3%。本方法具有操作简便、快速、准确的特点,可用于水产品中痕量二甲苯麝香和酮麝香的日常检测。 展开更多
关键词 多重吸附同步净化 气相色谱-质谱 二甲苯麝香 酮麝香 水产品 multiple adsorption synchronous purification( MASP) gas chromatography-mass spectrometry(GC-MS)
下载PDF
Nonlinear study of the dynamic behavior of a string-beam coupled system under combined excitations 被引量:3
12
作者 Y.S. Hamed M. Sayed +1 位作者 D.-X. Cao W. Zhang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第6期1034-1051,共18页
In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transve... In this paper,the nonlinear dynamic behavior of a string-beam coupled system subjected to external,parametric and tuned excitations is presented.The governing equations of motion are obtained for the nonlinear transverse vibrations of the string-beam coupled system which are described by a set of ordinary differential equations with two degrees of freedom.The case of 1:1 internal resonance between the modes of the beam and string,and the primary and combined resonance for the beam is considered.The method of multiple scales is utilized to analyze the nonlinear responses of the string-beam coupled system and obtain approximate solutions up to and including the second-order approximations.All resonance cases are extracted and investigated.Stability of the system is studied using frequency response equations and the phase-plane method.Numerical solutions are carried out and the results are presented graphically and discussed.The effects of the different parameters on both response and stability of the system are investigated.The reported results are compared to the available published work. 展开更多
关键词 1:1 internal resonance - String-beam - multiple scales Chaotic response Stability
下载PDF
A continuous-discontinuous cellular automaton method for cracks growth and coalescence in brittle material 被引量:3
13
作者 Fei Yan Xia-Ting Feng +1 位作者 Peng-Zhi Pan Shao-Jun Li 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2014年第1期73-83,共11页
A method of continuous-discontinuous cellular automaton for modeling the growth and coalescence of multiple cracks in brittle material is presented. The method uses the level set to track arbitrary discontinuities, an... A method of continuous-discontinuous cellular automaton for modeling the growth and coalescence of multiple cracks in brittle material is presented. The method uses the level set to track arbitrary discontinuities, and calculation grids are independent of the discontinuities and no remeshing are required with the crack growing. Based on Grif- fith fracture theory and Mohr-Coulumb criterion, a mixed fracture criterion for multiple cracks growth in brittle mate- rial is proposed. The method treats the junction and coales- cence of multiple cracks, and junction criterion and coales- cence criterion for brittle material are given, too. Besides, in order to overcome the tracking error in the level set ap- proximation for crack junction and coalescence, a dichotomy searching algorithm is proposed. Introduced the above the- ories into continuous-discontinuous cellular automaton, the present method can be applied to solving multiple crack growth in brittle material, and only cell stiffness is needed and no assembled global stiffness is needed. Some numerical examples are given to shown that the present method is efficient and accurate for crack junction, coalescence and percolation problems. 展开更多
关键词 Continuous-discontinuous cellular automatonmethod multiple crack growth Discontinuous cellular au-tomaton Junction criterion - Coalescence criterion
下载PDF
New CCD photometric investigation of the early-type overcontact binary BH Cen in the young star-forming Galactic cluster IC 2944 被引量:1
14
作者 Er-Gang Zhao Sheng-Bang Qian +2 位作者 Miloslav Zejda Bin Zhang Jia Zhang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第5期119-130,共12页
BH Cen is a short-period early-type binary with a period of 0.792^d in the extremely young star-forming cluster IC 2944. New multi-color CCD photometric light curves in U, B, V, R and I bands are presented and are ana... BH Cen is a short-period early-type binary with a period of 0.792^d in the extremely young star-forming cluster IC 2944. New multi-color CCD photometric light curves in U, B, V, R and I bands are presented and are analyzed by using the Wilson-Devinney code. It is detected that BH Cen is a high-mass-ratio overcontact binary with a fill-out factor of 46.4% and a mass ratio of 0.89. The derived orbital inclination i is 88.9 degrees, indicating that it is a totally eclipsing binary and the photometric parameters can be determined reliably. By adding new eclipse times, the orbital period changes in the binary are analyzed. It is confirmed that the period of BH Cen shows a long-term increase while it undergoes a cyclic oscillation with an amplitude of A3 = 0.024 d and a period of P3 = 50.3 yr. The high mass ratio, overcontact configuration and long-term continuous increase in the orbital period all suggest that BH Cen is in the evolutionary state after the shortest-period stage of Case A mass transfer.The continuous increase in period can be explained by mass transfer from the secondary component to the primary one at a rate of˙M2 = 2.8×10^-6 M⊙per year. The cyclic change can be plausibly explained by the presence of a third body because both components in the BH Cen system are early-type stars. Its mass is determined to be no less than 2.2 M⊙ at an orbital separation of about 32.5 AU. Since no third light was found during the photometric solution, it is possible that the third body may be a candidate for a compact object. 展开更多
关键词 binary (including multiple close - stars binaries eclipsing - stars early-type - stars evolution - stars individual (BH Cen)
下载PDF
MODELING THE STRESS-STRAIN CURVES UNDER DYNAMIC RECRYSTALLIZATION 被引量:1
15
作者 W. Gao T. Sakai and H. Miura( Department of Mechanical Engineering and Intelligent Systems, The University of Electro - Communica- tions, Chofu, Tokyo 182 - 8585, Japan) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第1期349-358,共10页
An analytical model for dynamic recrystallization (DRX) is studied based on the relative grain size model proposed by Sakai and Jonas, and the characteristic flow behaviors under DRX are analyzed and simulated. Int... An analytical model for dynamic recrystallization (DRX) is studied based on the relative grain size model proposed by Sakai and Jonas, and the characteristic flow behaviors under DRX are analyzed and simulated. Introducing the variation of dynamic grain size and the heterogeneous distribution of disolo- cation densities densities under DRX,a simple method for modeling and simulating DRX processes is developed by using Laplace transformation theory. The results derived from the present model agree well with the experimental results in literatures. This simulation can reproduce a number of features in DRX flow behaviors, for example,single and multiple peak flow behaviors followed by a steady state flow, the transition between them, and so on. 展开更多
关键词 dynamic recrystallization computer simulation stress - strain curve single and multiple peaks
下载PDF
An orbital period investigation of the Algol-type eclipsing binary VW Hydrae
16
作者 Jia Zhang Sheng-Bang Qian Boonrucksar Soonthomthum 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第3期307-314,共8页
Orbital period variations of the Algol-type eclipsing binary, VW Hydrae, are analyzed based on one newly determined eclipse time and the other times of light minima collected from the literature. It is discovered that... Orbital period variations of the Algol-type eclipsing binary, VW Hydrae, are analyzed based on one newly determined eclipse time and the other times of light minima collected from the literature. It is discovered that the orbital period shows a continuous increase at a rate ofdP/dt = +6.34 × 10^-7 d yr^-1 while it undergoes a cyclic change with an amplitude of 0.0639 d and a period of 51.5 yr. After the long-term period increase and the large-amplitude period oscillation were subtracted from the O-C curve, the residuals of the photoelectric and CCD data indicate a small-amplitude cyclic variation with a period of 8.75 yr and a small amplitude of 0.0048 d. The continuous period increase indicates a conservative mass transfer at a rate of dM2/dt = 7.89 × 10^-8 M⊙ yr^-1 from the secondary to the primary. The period increase may be caused by a combination of the mass transfer from the secondary to the primary and the angular momentum transfer from the binary system to the circumbinary disk. The two cyclic period oscillations can be explained by light-travel time effects via the presence of additional bodies. The small-amplitude periodic change indicates the existence of a less massive component with mass M3 〉 0.53 M⊙, while the large-amplitude one is caused by the presence of a more massive component with mass M4 〉 2.84M⊙. The ultraviolet source in the system reported by Kviz & Rufener (1987) may be one of the additional components, and it is possible that the more massive one may be an unseen neutron star or black hole. The rapid period increase and the possibility of the presence of two additional components in the binary make it a very interesting system to study. New photometric and high-resolution spectroscopic observations and a detailed investigation of those data are required in the future. 展开更多
关键词 STARS BINARIES close - stars BINARIES eclipsing - multiple stars - stars individual (VW Hya)
下载PDF
Nonstationary Filtering for Markov Jumping Systems with Fading Channel and Multiplicative Noises
17
作者 Yang Zhan Daijun Wei 《Journal of Applied Mathematics and Physics》 2021年第4期529-544,共16页
This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>... This paper studies the nonstationary filtering problem of Markov jump system under <span style="white-space:nowrap;"><i>l</i><sub>2</sub> - <i>l</i><sub>∞</sub> </span>performance. Due to the difference in propagation channels, signal strength and phase will inevitably change randomly and cause the waste of signals resources. In response to this problem, a channel fading model with multiplicative noise is introduced. And then a nonstationary filter, which receives signals more efficiently is designed. Meanwhile Lyapunov function is constructed for error analysis. Finally, the gain matrix for filtering is obtained by solving the matrix inequality, and the results showed that the nonstationary filter converges to the stable point more quickly than the traditional asynchronous filter, the stability of the designed filter is verified. 展开更多
关键词 Markov Jumping System l2 - l Performance Fading Channel Nonstationary Filtering multiplicative Noises
下载PDF
改良俯卧折刀位在马蹄形肛瘘术中的应用
18
作者 刘丽 蔡云霞 万丽萍 《华夏医学》 CAS 2023年第6期155-159,共5页
目的:探讨改良俯卧折刀位在多切口拖管术联合中医挂线应用于马蹄形肛瘘手术中的效果。方法:选择60例马蹄形肛瘘患者,按照随机数字表法分为两组,每组30例。两组均进行多切口拖管术联合中医挂线治疗,对照组以截石位进行手术,观察组以改良... 目的:探讨改良俯卧折刀位在多切口拖管术联合中医挂线应用于马蹄形肛瘘手术中的效果。方法:选择60例马蹄形肛瘘患者,按照随机数字表法分为两组,每组30例。两组均进行多切口拖管术联合中医挂线治疗,对照组以截石位进行手术,观察组以改良俯卧折刀位进行手术。比较两组术中生命体征、体位摆放时间、手术满意度与体位不良反应发生情况。结果:两组术中生命体征比较,差异无统计学意义(P>0.05)。观察组体位摆放时间短于对照组,满意度高于对照组,手术体位不良反应发生率低于对照组,以上差异均有统计学意义(P<0.05)。结论:多切口拖管术联合中医挂线在马蹄形肛瘘手术中应用改良俯卧折刀位效果确切,体位摆放时间短,患者满意度高,且不会对术中生命体征造成不良影响。 展开更多
关键词 马蹄形肛瘘手术 改良俯卧折刀位 多切口拖管术 中医挂线
下载PDF
面向DCU非一致控制流的编译优化 被引量:2
19
作者 杨小艺 赵荣彩 +2 位作者 王洪生 韩林 徐坤坤 《计算机应用》 CSCD 北大核心 2023年第10期3170-3177,共8页
国产DCU采用单指令多线程(SIMT)的并行执行模型,在程序执行时核函数内会产生非一致控制流,导致线程束中的线程部分只能串行执行,即线程束分化。针对核函数的性能因线程束分化受到严重制约的问题,提出一种减少线程束分化时间的编译优化... 国产DCU采用单指令多线程(SIMT)的并行执行模型,在程序执行时核函数内会产生非一致控制流,导致线程束中的线程部分只能串行执行,即线程束分化。针对核函数的性能因线程束分化受到严重制约的问题,提出一种减少线程束分化时间的编译优化方法——部分控制流合并(PCFM)。首先,通过散度分析找到同构且含有大量相同指令和相似指令的可融合发散区域;其次,统计合并后节省的指令周期百分比,从而评估可融合发散区域的融合盈利;最后,查找对齐序列,并合并有收益的可融合发散区域。在DCU上使用PCFM测试从图形处理器(GPU)基准测试套件Rodinia和经典的排序算法中选择的测试用例,实验结果表明,PCFM对测试用例能够取得1.146的平均加速比,与分支融合+尾合并方法相比,使用PCFM的加速比平均提高了5.72%。可见,所提方法减少线程束分化的效果更好。 展开更多
关键词 DCU 单指令多线程 线程束分化 复杂控制流 编译优化
下载PDF
Synthesis of spiro-cyclopropane derivatives containing multiple chiral centers 被引量:3
20
作者 黄慧 陈庆华 《Science China Chemistry》 SCIE EI CAS 1999年第3期268-276,共9页
Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem as... Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem asymmetric reaction can afford four new stereogenic centers with one reaction and give optically pure spiro-cyclopropane derivatives 5a--5d which are difficult to obtain by routine methods. The synthetic method for 5a--5d was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]^(20),IR,~1H NMR,^(13)C NMR, MS and elementary analysis. The absolute configuration of the sprio [5-l-menthyloxy-3-bromo butyrolactocyclopropane-3″, 3′(4′-methyloxy-5′-menthyloxybutyrolactone)] (5a) was established by X-ray crystallography. The work can provide important synthetic strategy in synthesis of some new optically active spiro-cyclopropane analogues and some biologically active molecules with complex structure. 展开更多
关键词 5-( l-menthyloxy)-3-bromo-2(5H)-furanone tandem reaction asymmetric double Michael addition /internal NUCLEOPHILIC SUBSTITUTION crystal structure spiro-cyclopropane derivatives with multiple chiral centers.
原文传递
上一页 1 2 11 下一页 到第
使用帮助 返回顶部