强极大TAF代数的交不可约D-模

本文研究了强极大TAF代数的交不可约D-模的有关性质.利用矩阵单元链的方法,证明了全上三角矩阵代数中任一D-模等于包含它的所有交不可约D-模的交,建立了强极大TAF代数的交不可约D-模与矩阵单元链之间的对应关系,推广了强极大TAF代数中关于理想的若干性质.

Riesz代数上的d-模(英文)

本文引入了Riesz代数上d-模的概念.利用正算子理论讨论了可交换的Riesz代数上的d-模的二次共轭空间的d-模结构,并且研究了由格同态算子或区间保持算子产生的主理想上的特殊d-模.

绝对D-纯模(英文)

引入绝对D-纯模的概念,并讨论了绝对D-纯模类对直和、D-纯子模、扩张的封闭性;研究了D-纯平坦模和D-纯内射模的关系与性质.

基于ARFIMA(p,d,q)模型的中国股市长期记忆性研究

本文运用三种估计时间序列长期记忆模型(ARFIMA(p,d,q)模型)的方法(MLE、SPR和GPH)对中国股市的长期记忆性特征进行了实证研究,研究显示出MLE方法优于GPH与SPR方法,并得出中国股票市场具有一般新兴股票市场的特征—长期记忆性,但中国股票市场的这种记忆性在逐渐弱化。

Error modeling of 3-RSR parallel robot based on D-H transformation matrix

By selecting any one limb of 3-RSR parallel robot as a research object, the paper establishes a position and orienta- tion relationship matrix between the moving platform and the base by means of Denavit-Hartenberg （D-H） transformation matrix. The error mapping model is derived from original error to the error of the platform by using matrix differential method. This model contains all geometric original errors of the robot. The nonlinear implicit function relation between po- sition and orientation error of the platform and the original geometric errors is simplified as a linear explicit function rela- tion. The results provide a basis for further studying error analysis and error compensation.

推出拉回及模的内射性

用加法反变函子HomR(-,E)作用于推出图,得到新的交换图,并做其拉回,然后利用推出图和拉回图的性质刻画了推出图和拉回图与强D-内射模、强P-内射模、强极小内射模、内射模之间的关系.

TF-投射模与TF-投射维数

利用非交换环上的无挠模的概念,引入TF-投射模,也定义相应的同调维数.称左R-模M为TF-投射模,是指对任何无挠模T,都有Ext1R(M,T)=0.讨论TF-投射模与D-平坦模的关系,证明TF-投射整体维数为0的环都是QF环.最后,用TF-投射模维数刻画右强P-凝聚左Noether环.

d—连续模分解定理的改善

在文献[1]中,作者曾证明过这样一个定理:若M是d—连续模,则M=N+N′,此处N=(?),每个A_i都是局部模且有限个A_i的和总是M的直和项,N′是满足Rad(N′):N′的M的直和项。本文通篇皆用Rad表示Jacobson根。对上述分解定理,可作如下改善,即把代数和加强为直和。定理若M是d—连续的,则M=N+N′,此处N=(?)A_i,每个A_i都是局部模且Rad(N′)=N′。为便于参阅,将定理证明中需引用的在文献[1]中证明或引用过的结果开列于后: (A)、A是B在M中的加性补当且仅当M=A+B且A∩B是A的小子模。

某类特殊环上d—连续模的结构

In the paper,we using the notation in [1],determine the structure of d-continuous modules over some special rings.

完全环上d－连续模的结构

在文献［１］及［２］的基础上，本文研究了某一特殊环类亦即完全环上ｄ－连续模的结构。并获得了下面的结果：若Ｍ是完全环Ｒ上ｄ－连续模，则：Ｍ＝ＮｏＮ１…Ｎｎ其中（ａ）Ｎ０是拟投射Ｒ－模（ｂ）每－Ｎλ（１≤ｉ≤ｎ）是不可分ｄ─连续模但不是拟投射Ｒ－模且不同构于Ｎｏ的任一不可分直和项， １≤ｉ≠ｊ≤ｎ，Ｎｉ与Ｎｊ的投射覆盖皆不同构．（ｃ）存在Ｒ的理想Ｂ及右理想Ａ１，Ａ２，…，Ａｔ，不可分益等元ｅ１，ｅ２…，ｅｔ使（ｉ）ＮｉｅｉＲ／ｅｉＡ，ｅｊＲｅｉＡ＝ｅｉＢ１≤ｉ≤ｔ（ｉｉ）对Ｎ０任一不可分直和项Ｋ，存在Ｒ的某不可分幂等元ｅ，使ＫｅＲ／ｅＢ。

Experimental measurement and thermodynamic modeling of binary and ternary solid–liquid phase equilibrium for the systems formed by L-arabinose,D-xylose and water

Solid–liquid phase equilibrium data for binary(L-arabinose–water) and(D-xylose–water) systems at temperatures from(269.85–298.05) K and ternary(L-arabinose–D-xylose–water) system at temperatures of 273.85 K,278.85 K and 284.45 K were measured at atmospheric pressure.The ternary phase diagrams of the systems were constructed on the base of the measured solubility.Two pure solid phases were formed at given temperatures,including pure L-arabinose and pure D-xylose,which were con firmed and determined by the method of Schreinemakers' wet residue.At the same temperature,the crystallization region of L-arabinose was larger than D-xylose's.The acquired solubility data were then correlated using the NRTL model,Wilson model and Xu model.The calculated solubility with the three models agreed well with the experimental values.

Field-Based Automated Survey for Extracting Tree Inventory Attributes and 3-D Models in a Forested Area

Acquisition of tree inventory parameters such as tree position with respect to a local reference coordinate system, tree height, dbh （diameter breast height） and other associated tree attributes is a tedious process, time consuming, costly and labour intensive. An automatic collection and processing in the field could expedite the process of tree inventory survey and data management. The advent of handheld laser equipments such as the MDL LaserAce 300, should allow rapid acquisition of tree attributes. The instrument measures distances, differences in height and horizontal bearing automatically. This paper describes a study about the automated process of retrieving tree positions, their respective attributes and the creation of 3-D model （three-dimensional model）. A software developed in-house known as ASSIST （automated spatial survey information system） was utilized together with the MI）I, LaserAce 300, being the hardware component of the automated system. The capability of MDL LaserAce 9300 in extracting information regarding tree inventory attributes and the 3-D model encompassing the study area was investigated. The results were checked against the data sets acquired by a total station traversing and tacheometric survey respectively. The accuracy of the horizontal and vertical position of points gathered was critically assessed. The accuracy of the MDL LaserAce 300 was found to be less than ±2 m for both planimetric （horizontal） and vertical （height） in the construction of the 3-D model. The study demonstrates the effectiveness of a field-based automation system as a viable option to support forest application requirement.

Modeling and optimization of cooling slope process parameters for semi-solid casting of A356 Al alloy

Semi-solid processing （SSP） of A356 aluminum alloy was discussed via cooling slope （CS） method. The D-optimal design of experiment （DODE） was employed for experimental design and analysis of results. 38 random experiments obtained by software were carried out. In experimental stage, the molten aluminum alloy was poured on an inclined plate with different lengths of 100, 300 and 500 mm set at 30°, 45° and 60° of slope angles respectively. Three different pouring temperatures of 660, 680 and 700 ℃ were also used. After the casting process, the partial re-melting treatment was carried out at 590 ℃ for different isothermal time of 5, 8 or 12 min. The combined effect of these factors on globularity of the primary α（Al） crystals was investigated and optimized using DODE. The results indicated that the primary dendritic phase in the conventionally cast A356 alloy was transformed into a non-dendritic one in ingots cast over a cooling plate. The CS processed samples exhibited a globular structure only after re-heating to semi-solid region. The optimum values of pouring temperature, cooling length, slope angle and isothermal holding time were found to be 660 ℃, 360 mm, 48°, and 9 min, respectively. In this case, the globularity of primary crystals was obtained, about 0.91. The obtained model is highly significant with a correlation coefficient of 0.9860.

Multi-objective Thermal Optimization of Dual-input Aeronautic Static Inverter Based on MOEA/D

To solve the multi-variable and multi-objective optimization problem in the thermal design process of the dual-input aeronautic static inverter,an optimization method based on the combination of the multi-objective evolutionary algorithm based on decomposition(MOEA/D)and the fuzzy set theory is proposed.The heat transfer path of the power device is analyzed and an equivalent heat circuit is conducted.We take junction temperature of the power device,mass,and cost of the heat sink as optimization goals,and take the heat sink structure parameters as design variables to conduct thermal optimization based on MOEA/D.This paper carries out a comparative study,and the results show that the proposed improved algorithm can meet the different requirements for multi-objective weights,and have good rapidity and robustness.

3-D numerical modelling of Domino failure of hard rock pillars in Fetr6 Chromite Mine, Iran, and comparison with empirical methods

Fetr6 is an underground mine using the stope-and-pillar mining method. As there was some evidence regarding pillar failure in this mine, improving works such as roof support and replacing existing pillars with concrete pillars (CP) were carried out. During the construction of the second CP, in the space between the remaining pillars, one of the pillars failed leading to the progressive failure of other pillars until 4 000 m 2 of mine had collapsed within a few minutes. In this work, this phenomenon is described by applying both numerical and empirical methods and the respective results are compared. The results of numerical modelling are found to be closer to the actual condition than those of the empirical method. Also, a width-to-height (W/H) ratio less than 1, an inadequate support system and the absence of a detailed program for pillar recovery are shown to be the most important causes of the Domino failure in this mine.

TIME-FREQUENCY 2-D LMS BASED LONG-RANGE CHANNEL PREDICTION FOR WIRELESS OFDM SYSTEMS

Adaptive modulation can optimize the spectrum efficiency and system performance with the channel state information achieved by the long-range channel prediction. To avoid re-estimating channel correlation function as the channel stationarity varies and to track the channel adaptively, LMS （Least-Mean-Square） based long-range channel prediction is discussed in the existing literature, but it needs long observation interval to reach the convergence. Given that all OFDM （Orthogonal Frequency Division Multiplexing） subcarriers have the identical time-domain correlation and stationarity during the same time interval, this paper proposed a 2-D LMS based predictor which updates the filter weights in both time and frequency domain. The proposed scheme can effectively decrease the observation intervals and significantly speed up the convergence than the conventional LMS and Parallel LMS （PLMS）. Complexity analysis and simulation results prove that the proposed scheme can improve the BER （Bit Error Rate） performance and spectrum efficiency with negligible complexity increase.

In situ Nanomechanical Research on Large-Scale Plastic Deformation of Individual Ultrathin Multi-walled Carbon Nanotube

Carbon nanotubes are a promising candidate for the application of flexible electronics due to the ultrahigh intrinsic conductivity and excellent mechanical flexibility. In the present work, the morphology of the ultrathin (diameter<20 nm) multi-walled carbon nanotubes (MWCNTs) under an axial compression was investigated by using in-situ transmission electron microscopy. Moreover, the overall dynamic deformation processes and the force-displacement (F-D) curves of the MWCNTs were also examined. Interestingly, the MWCNTs almost restored their original morphology after 15 loading-unloading cycles. The deformation and recovery process indicate that the MWCNTs are flexible and exhibit excellent durability against compression. The Young’s modulus of the MWCNTs is estimated with the value of ∽0.655 TPa derived from the F-D curves fitting. Our results suggest that the ultrathin carbon nanotube structures may have great application potentials in flexible devices.

Simulation by Dislocation Model and Anomaly Property Determination of Huge Leveling Deformation at Linfen Seismic Station

In this study,under the assumption that the two huge leveling deformation anomalies at Linfen seismic station were caused by the Luoyunshan fault( Tumen-Yuli section)movement, we computed the vertical deformation field distribution based on the rectangular fault dislocation model and measured the ground deformation field of the study area using D-InS AR technology. The results are as follows:( 1) Theoretically,the ground vertical deformation field caused by fault movement could be within the elliptical deformation area with the long axis parallel to the fault strike. The largest deformation region is located in the center of the area in the hanging wall of the fault,and the deformation gradually decreases to zero toward the periphery; the impact range induced by the two deformations is respectively as follows: The long axes are about 18 km and26km,the short axes are about 12 km and 17 km and the obvious deformation amplitude is about 1- 3mm and 4- 14 mm.( 2) The measured deformation field by D-InS AR shows that there is no continuous deformation area consistent with the fault strike,and only the presence of land subsidence possibly caused by groundwater excessive exploitation,with the deformation amplitude about 10- 12 mm and 1- 5mm.( 3) The measured deformation field is not consistent with the theoretical result on deformation area and amplitude,which indicates that the fault movement is not the main cause of Linfen huge leveling deformation,but may rather be because of local deformation of the soil layers in the hanging wall of the fault.( 4) By combining the fault dislocation model simulation with the D-InS AR technology measurement,we can determine effectively the nature of the anomalyof the huge cross-fault leveling deformation,thus provide scientific basis for verification of significant leveling anomalies.

Modeling of Stochastic Magnetic Perturbation by RWMEF-Coils on NSTX

A 3-D field line integration code, TRIP3D has been modified to model stochastic magnetic perturbation produced by a resistive wall mode, error field （ RWMEF ） coil in the NSTX tokamak with very low aspect ratio. The RWMEF-coil has two turns, which may produce stochastic fields with the toroidal mode number of n = 1 or 3. In this study, it is found that the stochastic field of n = 3 is larger than that of n=-1 for the same coil current. Two divertor discharges with lower single null （ LSN ） and double null （ DN ） configurations in the NSTX have been modeled with different RWMEF-coil currents and toroidal modes.

Investigations and feedback on the training mode of professional master's degree of clinical pharmacy in Peking University and the preliminary exploration of Pharm. D. Education

In order to carry out the comprehensive reform of the professional master’s degree training mode of clinical pharmacy, we carried out interviews among 91 persons on the professional master’s degree of clinical pharmacy in Peking University School of Pharmaceutical Sciences and collected extensive feedback. We preliminaries explore the mode of Doctor of Pharmacy（Pharm. D.） Education, laying the foundation for Doctor’s education of professional clinical pharmacy in China. We conducted investigations and interviews among 91 clinical pharmacists and students of Peking University School of Pharmaceutical Sciences on the training of professional master’s degree and Pharm. D. education mode, which includes 67 postgraduates and 24 clinical pharmacists. Respondents put forward the problems of training mode and corresponding suggestions and opinions from different aspects during the investigation and interview. The results mainly divide into four aspects： curriculum setting, clinical practice, assessme nt system and teaching resources. Respondents put forward effective feedback on the above four aspects, which are beneficial to the comprehensive reform of the training mode of professional master degree in clinical pharmacy and preliminary exploration of Pharm. D. Education in China.