川东北地区须家河组储层特征研究

通过钻井取心和露头采样测试、岩石薄片分析及扫描电镜分析等手段,对川东北地区须家河组的 储层岩石学特征、储层空间类型、成岩作用类型、孔隙结构及孔隙类型等进行了深入分析。结果表明：川 东北地区须家河组储层砂岩以中-细粒为主,成分成熟度较低,结构成熟度中等;储集空间主要为残余原 生粒间孔隙、次生溶蚀孔隙和裂缝,孔隙结构以小孔、细喉型为主。研究区孔渗较低,为典型的低孔、低渗 至特低孔、特低渗储层。     

基于互信息下粒子群优化的属性约简算法

最小属性约简是粗糙集理论中属性约简的优化问题.在寻找最小属性约简的问题上,基于粒子群优化的属性约简算法（ARPSO算法）优于传统的属性约简算法.在现有的ARPSO算法中,正域部分通常被作为启发式信息,但是它并不能够很好地衡量不确定性,而互信息是粗糙集理论中一种更有效的度量不确定信息的重要工具.为此,提出基于互信息下的粒子群优化的属性约简算法（MIPSO算法）,该算法把互信息作为适应度函数,通过增强粒子能迅速靠近吸引子的这一特性,改进了内嵌区域震荡搜索的粒子群优化算法（简记为RSPSO算法）,防止算法较早的陷入局部最优,使得粒子群中的粒子更快的找到最优值,因此使得算法尽可能实现全局收敛.实验结果表明,该算法不仅提高了寻优的能力,加快了算法的速度,提升了算法的精度,而且也能够使得约简后剩余属性的互信息值与约简前所有属性的互信息值近似相等.     

Application of neural networks to prediction of phase transport characteristics in high-pressure two-phase turbulent bubbly flows

The phase transport phenomenon of the high-pressure two-phase turbulent bubbly flow involves complicated interfacial interactions of the mass, momentum, and energy transfer processes between phases, revealing that an enormous effort is required in characterizing the liquid–gas flow behavior. Nonetheless, the instantaneous information of bubbly flow properties is often desired for many industrial applications. This investigation aims to demonstrate the successful use of neural networks in the real-time determination of two-phase flow properties at elevated pressures. Three back-propagation neural networks, trained with the simulation results of a comprehensive theoretical model, are established to predict the transport characteristics (specifically the distributions of void-fraction and axial liquid–gas velocities) of upward turbulent bubbly pipe flows at pressures covering 3.5–7.0 MPa. Comparisons of the predictions with the test target vectors indicate that the averaged root-mean-squared (RMS) error for each one of three back-propagation neural networks is within 4.59%. In addition, this study appraises the effects of different network parameters, including the number of hidden nodes, the type of transfer function, the number of training pairs, the learning rate-increasing ratio, the learning rate-decreasing ratio, and the momentum value, on the training quality of neural networks.     

Effect of Tissue Infrastructure on Electric Conductance of Vegetable Stems

ABSTRACT: This study measures the electric conductance and examines the microscopic structure of bamboo shoots, sugarcane, lettuce stem, and mustard stem. The electric conductance readings vary from 0.09 S/m to 0.72 S/m across the stem, and from 0.19 S/m to 0.46 S/m along the stem. The electric conductance along the stem is higher than the electric conductance across the stem in bamboo shoots and sugarcane, while the reverse is true in lettuce stem and mustard stem. The orientation of vascular bundles and the shape of parenchyma cells are proposed to account for the different conductance readings from the same vegetable in different directions. The orientation of vascular bundles appear to influence electric conductance more than the shape of parenchyma cells when both factors are present in the same time.     

Composite k-arbiters

The k-arbiter is a useful concept to solve the distributed h-out-of-k mutual exclusion problem. The distributed h-out-of-k mutual exclusion algorithms, based on the k-arbiter, have the benefits of high fault tolerance and low message cost. However, according to the definition of the k-arbiter, it is required to have a nonempty intersection among any (κ + 1) quorums in a k-arbiter. Consequently, constructing k-arbiters is difficult. The coterie join operation proposed by Neilsen and Mizuno (1992) produces a new and larger coterie by joining known coteries. By extending the coterie join operation, we first propose a k-arbiter join operation to construct a new and larger k-arbiter from known k-arbiters for a large system. Then, we derive a necessary and sufficient condition for the k-arbiter join operation to construct a nondominated joined k-arbiter. Moreover, we discuss availability properties of the joined k-arbiters. We observe that, by selecting proper k-arbiters, the joined k-arbiter can provide a higher availability than that of the original input. Finally, we propose a k-arbiter compound, operation to construct k-arbiters by using coteries and/or k-coteries. By that way, the problem of constructing k-arbiters can be reduced to the problem of constructing coteries and/or k-coteries     

Real-Time Access Control and Reservation on B-Tree Indexed Data

This paper proposes methodologiesto control the access of B⁺-tree-indexed datain a batch and firm real-time fashion. Algorithms are proposedto insert, query, delete, and rebalance B⁺-tree-indexeddata based on the non-real-time algorithms proposed in Kerttu,Eljas, and Tatu (1996) and the idea of priority inheritance (Sha,Rajkumar, and Lehoczky, 1990). We propose methodologies to reducethe number of disk I/O to improve the system performancewithout introducing more priority inversion. When the schedulabilityof requests with critical timing constraints is highly important,we propose a mechanism for data reservation based on the ideaof preemption level and the Stack Resource Policy (Baker, 1990).The performance of our methodologies was evaluated by a seriesof experiments, from which we have obtained encouraging results.     

Relationship between age and clinical characteristics of patients with gastric cancer

The relationship between the prognosis and age of patients with gastric cancer is controversial. To evaluate whether there is a biological characteristic specific to the age of patients, we examined the clinical characteristics of patients with gastric cancer with special reference to their age. Based on a prospective database, a retrospective study of 419 patients who underwent radical gastrectomy for cure in the past 6 years was conducted. Clinical characteristics including gender, gross appearance of the tumour (Borrmann's classification, tumour location), histopathology (depth of tumour invasion, lymph node status, Lauren's classification and degree of tumour cell differentiation) and TNM tumour stage were analysed in six different age groups (< 39, 40-49, 50-59, 60-69, 70-79, > 80 years). The mean age of the 419 patients was 64.6 years (range from 26-91) and the peak age incidence of gastric cancer (46.3%) was in the 60-69 year old age group. The male: female ratio was 4.6:1 on the whole and male gender predominated at ages > 60. The proportion of diffuse type tumours (68.4%) by Lauren's criteria in the young age group (< 39 yrs) decreased with age (25% in the > 80 years group; P < 0.001). Similarly, the proportion of poorly-differentiated tumours (89.5%) in the young age group (< 39 yrs) decreased with advancing age (P < 0.001). These findings suggest that both diffuse type and poorly-differentiated tumours predominate in younger patients and, without considering the factor of delay in diagnosis, may explain the poorer prognosis demonstrated in younger patients.     

Analog and digital circuits using organic thin-film transistors onpolyester substrates

We have fabricated and characterized analog and digital circuits using organic thin-film transistors on polyester film substrates. These are the first reported dynamic results for organic circuits fabricated on polyester substrates. The high-performance pentacene transistors yield circuits with the highest reported clock frequencies for organic circuits     

The impacts of control gate voltage on the cycling endurance ofsplit gate flash memory

In this paper, the “erase” degradation in program/erase (P/E) cycling endurance of split-gate flash memory has been investigated. It is found that increasing the control-gate (CG) voltage (V_CG) during erasing can slow down the “window closure” of cycling endurance since a higher V_CG can “push” the FG potential into gradual part of I_Read-out -V_FG curve and in turn reduce the read-out current degradation. Moreover, the experimental results show that scaling down the gate oxide thickness under FG can effectively reduce the I_Read-out degradation in the cycling endurance test     

Synchronous thermal wave IR video imaging for nondestructive evaluation

We describe a system for real-time processing of infrared video images in synchronism with the time-dependence of the target object's temperature. The system can either be used either with periodic or pulsed heating of the target. With periodic heating, the system operates as if it were a collection of lock-in amplifiers, one for each of the quarter of the million pixels of the image. With pulsed heating, it operates as if it consisted of a similar number of box-car averagers. In both cases, the signal-to-noise ratio and temperature sensitivity of the infrared camera are improved. The technique lends itself to a wide spectrum of NDE applications.