Evaluation of Soybean Seedcoat Cracking During Drying:PART II. Using MRI

MRI techniques were developed and employed for non-destructive and noninvasive study of seedcoat cracking in low moisture soybean kernels during heated air drying. Proton density image and transient moisture distribution profile of a single soybean kernel can be obtained using MRI. These MRI techniques proved to be particularly useful for the continuous observation of initiation and propagation of seedcoat cracking during the entire period of drying process without interruption.

The proton density images of soybean kernels showed that seedcoat cracking was initiated perpendicular to the long axis of the kernel near the hilum. The transient moisture distribution profiles in soybean kernels during drying indicate that moisture gradient developed during drying was higher in the seedcoat than in the cotyledon. Drying temperature and initial average moisture content were positively correlated with the soyhean seedcoat crackig. The location of the     

制备2，4－二氯－5－氟苯甲酰乙酸甲酯的缩合剂及工艺研究

通过３种不同的碱来制备２，４－二氯－５－氟苯甲酰乙酸甲酯，优选得到了其最佳缩合剂甲醇钠；同时应用正交设计实验，研究了原料配比、反应时间、反应温度对收率的影响，在优选条件下收率为７８．５％。     

Surgical treatment of unilateral alveolar cleft

In this study, 16 cases of unilateral alveolar cleft with cleft lip and palate were repaired with autografts of cancellous bone (13 cases) or hydroxyapatite (3 cases). The grafts were covered by reflected mucoperiosteal flaps and a mucosal flap from the upper lip. Twelve of the thirteen cases were followed up for 1-5 years. Nine of whom using cancellous bone had bony continuity of the maxilla and 7 cases erupted permanent maxillary canines within the area of autografts. None of the 3 cases using hydroxyapatite erupted a canine tooth. The results showed that autograft was better than hydroxyapatite in terms of maxillary canine eruption.     

高频热处理技术的新进展

就高频感应加热设备、高频热处理的发展等若干问题进行较为详尽的评介,并提出几点看法.     

Pultruded fibre reinforced polyurethane composites II. Effect of processing parameters on mechanical and thermal properties

This paper presents a novel process for the fabrication of pultruded polyurethane (PU) composites. The effects of the processing parameters on the mechanical properties (flexural strength and flexural modulus, etc.) and thermal properties (HDT) of the fibre reinforced PU composites by pultrusion have been studied. The processing parameters investigated include pulling rate (in-line speed), die temperature, filler type and content, and post-cure time and temperature. Results show that the composites possessed various optimum pulling rates at different die temperatures. On the basis of the DSC diagram, the swelling ratio, the mechanical properties and the thermal properties of composites, the optimum die temperature can be determined. It is found that the mechanical and thermal properties increase with filler content for various types of filler. The mechanical and thermal properties increase at a suitable post-cure temperature and time. Furthermore, the properties which decreased due to the degradation of composite materials for a long post-cure time will be discussed.     

An extraction method to determine interconnect parasitic parameters

Interconnect parasitic parameters in integrated circuits have significant impact on circuit speed. An accurate monitoring of these parameters can help to improve interconnect performance during process development, provide information for circuit design, or give useful reference for circuit failure analysis. Existing extraction methods either are destructive (such as SEM measurement) or can determine only partial parasitic parameters (such as large capacitor measurement). In this paper, we present a new method for extracting interconnect parasitic parameters, which can simultaneously determine the interlayer and intralayer capacitances, line resistance, and effective line width. The method is based on two test patterns of the same structure with different dimensions. The structure consumes less wafer area than existing methods. The method shows good agreement with SEM measurement of dielectric thickness in both nonglobal planarized and chemical-mechanical polished processes, and gives accurate prediction of the process spread of a ring oscillator speed over a wafer     

A linear minimum mean square error multiuser receiver inRayleigh-fading channels

We generalize the multiuser (CDMA spread spectrum) communication systems to the fading environments. We first extend Verdu's (1986) conventional optimum receiver to Rayleigh-fading environments and then evaluate its performance. Having no knowledge of the received power at the receiving end, we therefore need an estimator to efficiently estimate the received signal strength of each user in fading environments. A linear minimum mean square error (LMMSE) unbiased estimator is proposed to attain this goal. By using the minimum mean square error (MMSE) Bayesian estimation, we further propose the LMMSE bit estimator for efficient demodulation. Its performance is close to the optimum multiuser receiver but with a much simpler polynomial complexity. To further reduce the complexity, we extend the LMMSE estimator to the sequential LMMSE estimator. In sequential estimation, we do not need to implement the matched filter banks and to perform the matrix inversion when estimating. In addition, it converges after approximately 2k iterations, where k is the number of users. With this fast convergence property and the simple structure, the sequential LMMSE estimator provides an attractive alternative to the implementation of a multiuser system     

Efficient dynamic synchronous machine simulation with harmonics

Within this paper, an efficient procedure for the dynamic simulation of faulted synchronous machines operating in the presence of harmonics is presented. The algorithm employs steady-state frequency domain techniques for simulation of the transmission system sequence networks and time domain methods for synchronous machines represented in the odq frame of reference. The procedure affords greater accuracy than conventional fault analysis techniques based strictly on steady-state methods, yet requires far less computational time than full system dynamic simulations such as those using the EMTP     

加氢裂化复合催化剂使用技术的研究

使用1246与3762复合催化剂加氢裂化处理含焦化蜡油(50%以上)混合原料油时,催化剂不仅具有高脱氮能力、高转化率,同时,还具有好的加氢活性稳定性,为焦化蜡油的合理加工找到一条新路,并有显著的经济效益 。     

董公馆：嫁接之美

董公馆是一个6层楼的公寓，依山而建，业主将他交到设计师手里，让他在这基础上活活变出一个精美的“公馆”。