用矩阵法FTA进行非单调关联系统的早期不交化

本文针对带有重复事件的非单调关联系统故障树，定义了非单调关联系统的割集矩阵及不交化最小割集矩阵，利用矩阵变换实现故障树的早期不交化，从而为求解复杂非单调关联系统，解决其ＮＰ困难问题。

EX220-3挖掘机行走速度异常的故障排除

EX220-3型挖掘机是日本日立公司生产的小型履带式挖掘机,该挖掘机有工作装置、上部回转台和行走装置三部分组成。该挖掘机行走速度的改变主要通过行走马达的斜盘角和主泵位移角的配合来实现的,而行走速度控制电路允许挖掘机以三种不同的速度行走,通过对行走速度控制系统分析,找出了行走速度不变化或比规定速度慢的故障原因和排除方法,这对EX220-3挖掘机行走速度不变化或比规定速度慢故障诊断起到一定的指导作用。

SIFT算法中融合全局不变矩的特征变换

提出了一种融合全局几何特征的SIFT描述算子.该算法以特征点为中心,进行对数极坐标变换并建立同心圆区域,通过分析HU矩在离散状态下的变换情况,提取出在离散状态下具有RSTC不变性的不变量作为同心圆区域的特征向量.采用欧式距离作为度量标准进行图像匹配实验对比.结果表明,此算法通过结合全局特征与局部特征,提高了图像在旋转与尺度变化、视点变化、光照变化和图像模糊等各种变化下匹配的鲁棒性.

现代俄语格系统的弱化趋势

新时期的俄语发生了很大的变化,但主要是在词汇层面上。本文将在语言的语法层面上对语言变化做一个系统阐述,主要论述近年来俄语在格系统中所发生的变化。

关于收缩率和延伸率间偏差和颈缩分析I

根据收缩率和延伸率间密度不变时的公式可以推倒出它们之间颈缩的不等式。曲线很好地说明了它的走势。由偏差关系得出在小于14%时收缩偏差较好,在中间一段延伸偏差较好,大于一定值收缩率偏差又变好的规律。在64%偏差率时收缩率的值小于延伸率,它的真实性高1.32倍以上,最大偏差为1.64。推导出(√S0)3-S√S0+S0-2S<0等两个公式为颈缩发生推倒公式。据文献统计收缩率值在大于25%时比较多,而延伸率则在30%以下较多。双晶由剪应力引起,转位由拉应力引起。

代换——解答数学题的重要策略

在解答数学问题的过程中,可以根据题中的条件和结构恰当地进行代换。从而拉近未知和已知的距离,达到化繁为简、化难为易的目的。下面举例说明。 1 比值代换 当已知条件有连比(包括连等,连不等)时,一般都可以进行比值代换。

Transformations and Tautomeric Equilibrium among Different Intermediates in Proline-Catalyzed Reactions of Aldehydes or Ketones

The enamines, iminium ions, and oxazolidinones are thought to be the key intermediates in the proline-catalyzed reactions of aldehydes or ketones, but there is an extensive contro- versy about their roles. Here, the corresponding transition states connecting any two of the three kinds of species are located at the wB97XD/6-311＋＋G＊＊ level of theory. The calcula- tions demonstrate that the oxazolidinones are the predominant species in both the gas phase and solvents; there exists tautomeric equilibrium among these species and the equilibriums are controlled by the employed solvents and temperature in the reaction. These results demonstrate that the concentration and role of the mentioned species are controlled by the employed solvent and temperature. A new reaction pathway is presented herein for the trans- formation between iminium ions and oxazolidinones through iminium ion-water complex and oxazolidinone-water complex. The calculations demonstrate that the rate-limiting step in proline-catalyzed Mannich reaction between acetaldehyde/keteones and N-Boc imines is the formation of the C-C bond rather than the intermediates tautomerization. These calculations rationalize the available experimental observations and can be valuable in optimizing the experimental conditions of asymmetric organic-catalyzed reactions of aldehydes or ketones.

Genetic alterations in hepatocellular carcinoma: An update

Hepatocellular carcinoma(HCC) is one of the leading causes of cancer-related deaths worldwide. Although recent advances in therapeutic approaches for treating HCC have improved the prognoses of patients with HCC, this cancer is still associated with a poor survival rate mainly due to late diagnosis. Therefore, a diagnosis must be made sufficiently early to perform curative and effective treatments. There is a need for a deeper understanding of the molecular mechanisms underlying the initiation and progression of HCC because these mechanisms are critical for making early diagnoses and developing novel therapeutic strategies. Over the past decade, much progress has been made in elucidating the molecular mechanisms underlying hepatocarcinogenesis. In particular, recent advances in next-generation sequencing technologies have revealed numerous genetic alterations, including recurrently mutated genes and dysregulated signaling pathways in HCC. A better understanding of the genetic alterations in HCC could contribute to identifying potential driver mutations and discovering novel therapeutic targets in the future. In this article, we summarize the current advances in research on the genetic alterations, including genomic instability, single-nucleotide polymorphisms, somatic mutations and deregulated signaling pathways, implicated in the initiation and progression of HCC. We also attempt to elucidate some of the genetic mechanisms that contribute to making early diagnoses of and developing molecularly targeted therapies for HCC.

Comparison of signal reconstruction under different transforms

A newalgorithm, called Magnitude Cut, to recover a signal from its phase in the transform domain, is proposed.First, the recovery problem is converted to an equivalent convex optimization problem, and then it is solved by the block coordinate descent（ BCD） algorithm and the interior point algorithm. Finally, the one-dimensional and twodimensional signal reconstructions are implemented and the reconstruction results under the Fourier transform with a Gaussian random mask（ FTGM）, the Cauchy wavelets transform（ CWT）, the Fourier transform with a binary random mask（ FTBM） and the Gaussian random transform（ GRT） are also comparatively analyzed. The analysis results reveal that the M agnitude Cut method can reconstruct the original signal with the phase information of different transforms; and it needs less phase information to recover the signal from the phase of the FTGM or GRT than that of FTBM or CWT under the same reconstruction error.

Seasonal biochemical changes in composition of body wall tissues of sea cucumber Apostichopus japonicus

Seasonal variation in proximate, amino acid and fatty acid composition of the body wall of sea cucumber Apostichopus japonicus was evaluated. The proximate composition, except for ash content, changed significantly among seasons （P〈0.05）. Alanine, glycine, glutamic acid and asparagic acid were the most abundant amino acids. Total amino acid and essential amino acid contents both varied clearly with seasons （P〈0.05）. 16：0 and 16：1n7 were the primary saturated fatty acid （SFA） and monounsaturated fatty acid （MUFA） respectively for all months. EPA （20：5n-3）, AA （20：4n-6） and DHA （22：6n-3） were the major polyunsaturated fatty acids （PUFA）. The proportions of SFA and PUFA yielded significant seasonal variations （P〈0.001）, but MUFA did not changed significantly. The results indicated that the biochemical compositions of the body wall in A. japonieus were significantly influenced by seasons and that the body wall tissue is an excellent source of protein, MUFA and n-3 PUFA for humans.

Eddy generation and evolution in the North Pacific Subtropical Countercurrent(NPSC) zone

The seasonal generation and evolution of eddies in the region of the North Pacific Subtropical Countercurrent remain poorly understood due to the scarcity of available data.We used TOPEX/POSEIDON altimetry data from 1992 to 2007 to study the eddy field in this zone.We found that velocity shear between this region and the neighboring North Equatorial Current contributes greatly to the eddy generation.Furthermore,the eddy kinetic energy level(EKE) shows an annual cycle,maximum in April/May and minimum in December/January.Analyses of the temporal and spatial distributions of the eddy field revealed clearly that the velocity shear closely related to baroclinic instability processes.The eddy field seems to be more zonal than meridional,and the energy containing length scale shows a surprising lag of 2-3 months in comparison with the 1-D and 2-D EKE level.A similar phenomenon is observed in individual eddies in this zone.The results show that in this eddy field band,the velocity shear may drive the EKE level change so that the eddy field takes another 2-3 months to grow and interact to reach a relatively stable state.This explains the seasonal evolution of identifiable eddies.

Assessing Gray Scale Grades for Color Change of Dyed Fabrics via Image Processing Technology

Gray scale grades for color change of dyed fabrics are assessed via image processing technology.Digital images of groups of specimens are obtained,cropped,and saved as JPEG format.Relationships between gray scale grades for color change and the corresponding color differences calculated via image processing technology are investigated,compared with those obtained from high accurate computer color matching system.Results show that the new method is acceptable with an accuracy of 92.0% when the grading errors are of not more than one grade.

Characteristics of diurnal variations of warm-season precipitation over Xinjiang Province in China

Aimed at improving knowledge regarding the diurnal cycle of warm-season rainfall in northwestern China,this study investigated the diurnal variations of warm-season precipitation with different durations in Xinjiang,China,using an hourly gauge–satellite merged precipitation product during 2008 to 2019.Results show noticeable diurnal variations with distinctive regional features.The primary peak is in the early evening.Rainfall events with duration less than 3 h occur more often across the whole of Xinjiang and contribute more than half of the precipitation amount over its northern and southern peripheries,while rainfall events with duration more than 7 h over the Tianshan Mountains are responsible for the primary peak in the diurnal variations of warm-season precipitation.

Salt-Water Transport in Unsaturated Soils Under Crop Planting: Dynamics and Numerical Simulation

A laboratory salt-water dynamics experiment using unsaturated soils in packed silt loam and clay soil columns withdifferent soil texture profiles and groundwater levels under crops were conducted to study the changes of salt-waterdynamics induced by water uptake of crops and to propose the theoretical basis for the regulation and control of salt-water dynamics as well as to predict salinity levels. The HYDRUS 1D model was applied to simulate the one-dimensionalmovement of water and salt transport in the soil columns. The results showed that the salts mainly accumulated in theplow layer in the soil columns under crops. Soil water and salt both moved towards the plow layer due to soil waterabsorption by the crop root system. The salt contents in the column with lower groundwater were mostly greater thanthose with high groundwater. The water contents in the soil columns increased from top to the bottom due to plant rootwater uptake. The changes in groundwater level had little influence on water content of the root zone in the soil columnswith crop planting. Comparison between the simulated and the determined values showed that model simulation resultswere ideal, so it is practicable to do numerical simulation of soil salt and water transport by the HYDRUS 1D model.Furthermore, if the actual movement of salt and water in fields is to be described in detail, much work needs to be done.The most important thing is to refine the parameters and select precise boundary conditions.

Softening response under undrained compression following anisotropic consolidation

Experimental evidence has indicated that clay exhibits strain-softening response under undrained compression following anisotropic consolidation.The purpose of this work was to propose a modeling method under critical state theory of soil mechanics.Based on experimental data on different types of clay,a simple double-surface model was developed considering explicitly the location of critical state by incorporating the density state into constitutive equations.The model was then used to simulate undrained triaxial compression tests performed on isotropically and anisotropically consolidated samples with different stress ratios.The predictions were compared with experimental results.All simulations demonstrate that the proposed approach is capable of describing the drained and undrained compression behaviors following isotropic and anisotropic consolidations.

MPC of distillation column with side reactors for methyl acetate

This paper focuses on the dynamic control of distillation column with side reactors(SRC) for methyl acetate production. To obtain the optimum integrated structure and steady state simulation, the systematic design approach based on the concept of independent reaction amount is applied to the process of SRC for methyl acetate production. In addition to the basic control loops, multi-variable model predictive control modular with methyl acetate concentration and temperature of sensitive plate is designed. Then, based on process simulation software Aspen Plus, dynamic simulation of SRC for methyl acetate production is used to verify the effectiveness of the control scheme.

Deformation inhomogeneity due to sample-anvil friction in cylindrical compression test

Finite element(FEM)analysis was used to systematically evaluate the inhomogeneity of deformation in cylindrical samples with various sample-anvil friction coefficients,m.It was found that the level of friction strongly influences the deformation homogeneity,which increases significantly with the friction coefficient although the overall geometry of the samples almost remains the same when m >0.4.The position,at which the effective strain along the maximum radial direction in a compressed sample is equal to the equivalent strain of the sample,does not vary greatly with respect to both equivalent strain of the sample and m.Hardness measurements of compressed cylindrical 5056B Al alloy samples revealed a change of effective strain distribution similar to that revealed by FEM analysis.There exists a quantitative relationship between the hardness and the effective strain if no recrystallization or recovery occurs during the compression process.

Generalized Variational Inequalities and Wiener-Hopf Equations in Hilbert Spaces

In this paper,we consider the solvability of generalized variational inequalities involving multi-valued relaxed monotone operators in the framework of Hilbert spaces.Our results mainly improve the corresponding results announced by Verma[R U Verma,Generalized variational inequalities involving multivalued relaxed monotone operators,Appl Math Lett,1997,10：107-109]and many others.

On Variational Inequality and Fixed Point Problems

In this paper,A strong convergence theorem for a finite family of nonexpansive mappings and relaxed cocoercive mappings based on an iterative method in the framework of Hilbert spaces is established.

A New GMλ-KKM Theorem and Its Application to Saddle Points

In this paper,a new GMλ-KKM theorem is established for noncompact λ-hyperconvex metric spaces.As applications,the properties of the solution set of the variational inequality is shown and an existence theorem for saddle points is obtained.