Delineation of ECT images using global constraints and dynamic programming

A model-based delineation algorithm is presented. It is a flexible model fitting algorithm, approaching contour detection as an optimization problem. An objective function is introduced, which depends not only on local contour features, but also on a global shape constraint. The latter is implemented as the similarity to the instance of a parametric shape model. The algorithm optimizes both the contour points and the parameters of the model. As a result, both global and local characteristics of the contour are determined as a compromise between photometric data and prior knowledge. The method was applied to myocardial perfusion SPECT images, to delineate the entire left ventricle (endocardium and epicardium), including possible regions of reduced perfusion. By adapting the balance between the image data and the shape model, images with different characteristics can be processed, including Thallium-201 and MIBI scans.     

Efficient analysis tool for coupled-SAW-resonator filters

The advantages of the coupled-mode (COM) formalism and the transmission-matrix approach are combined in order to create exact and computationally efficient analysis and synthesis tools for the design of coupled surface acoustic wave resonator filters. The models for the filter components, in particular gratings, interdigital transducers (IDTs) and multistrip couplers (MSCs), are based on the COM approach that delivers closed-form expressions. To determine the pertinent COM parameters, the COM differential equations are solved and the solution is compared with analytically derived expressions from the transmission-matrix approach and the Green's function method. The most important second-order effects, such as energy storage, propagation loss, and mechanical and electrical loading, are fully taken into account. As an example, a two-pole, acoustically coupled resonator filter at 914.5 MHz on AT quartz is investigated. Excellent agreement between theory and measurement is found.     

Sequencing of multi‑robot behaviors using reinforcement learning

Given a collection of parameterized multi-robot controllers associated with individual behaviors designed for particular tasks, this paper considers the problem of how to sequence and instantiate the behaviors for the purpose of completing a more complex, overarching mission. In addition, uncertainties about the environment or even the mission specifications may require the robots to learn, in a cooperative manner, how best to sequence the behaviors. In this paper, we approach this problem by using reinforcement learning to approximate the solution to the computationally intractable sequencing problem, combined with an online gradient descent approach to selecting the individual behavior parameters, while the transitions among behaviors are triggered automatically when the behaviors have reached a desired performance level relative to a task performance cost. To illustrate the effectiveness of the proposed method, it is implemented on a team of differential-drive robots for solving two different missions, namely, convoy protection and object manipulation.     

論鋁酸盐溶液的蒸汽压

本文論述了鋁酸盐溶液蒸汽压的影响因素。作者用氫氧化钾、氫氧化钠、碳酸钾和氫氧化铝(或金屬銀)为原料,制备了試驗溶液产并使其组成尽量符合霞石熟料浸出后所得的铝酸盐溶液。用这种溶液进行的多次試驗表明,鋁酸盐溶液的蒸汽压随碱濃度的增加而阵低;当碱含量一定时,与氧化鋁的濃度无关。通过溶液沸点的試驗証明了沸点与溶液中氧化鋁的含量无关,溶液的活度也不取决于氧化铝含量的多少。通过試驗还証明了铝酸盐溶液是具有离子性的,但是某些学者所提出的溶液中具有高价离子的假說没有得到証实。     

流水作业线管道中熔体镁运动的流体动力学制度的研究

电解法制镁流水作业线是一个由管道连接的串联电解槽组成的流体动力学闭路回路,在自成的系统中可有几十台电解槽。在此系统中熔体流量超过80吨/小时,管道工作状态在很大程度上取决于它们的外形尺寸和结构。     

对3号结构钢同氯化物料浆接触时的耐腐蚀研究

在镁钛联合企业中,用石灰乳净化含氯气体时生成的次氯酸盐料浆在各种不同的工业部门找到了广阔的销路。除了商品料浆以外还有颇大数量不合标准的次氯酸盐料浆,需要进行净化处理。钛设计研究院研究出了用次氯酸盐料浆与镁钛生产的残料——氯化物升华物相互净化处理的工艺,提出将净化处理后的氯化物料浆作     

溅射NdFeB薄膜合金的磁各向异性SCIEI

用RF溅射方法在不同的基片温度下制备了非晶态和晶态NdFeB溥膜合金。研究了薄膜合金的磁各向异性。在600℃溅射得到的晶态样品具有强的垂直各向异性和高的矫顽力。由非晶态晶化得到的晶态合金也呈现了较强的垂直各向异性。     

INTERFACIAL EQUILIBRIUM IN Cu:Cu-Al DIFFUSION COUPLES

用“双套管法”淬火测定Cu:Cu-Al扩散偶中的相平衡,由于该法具有较快的冷却速度,保证了α/β相界面处于局部平衡.传统的淬火方法冷速通常是不够快的,不足以抑制β相的分解.较慢的冷却使界面形貌发生改变;测出的界面浓度是较低温度下的数值.有理由相信,Eifert等实验得到的各温度下都远较平衡浓度为高的α/β相界浓度,是由于实验过程中较慢的冷速所导致.     

АУ311-10A型动力头主轴工作条件的研究方法

苏联共产党代表大会(1959年)在创造高生产率专用组合机床及自动线方面,向机床制造者提出了艰巨的任务。按照工序高度集中的原则来建造高生产率设备,可以大大地提高劳动生产率和缩小生产面积。以组合化原则为基础来建立现代组合机床自动线,就有可能在较短的期间内设计和制造高生产率的组合机床和自动线。这一原则只有在机床零部件广泛通用化和标准化的基础上才可能实现。在现代组合机床和自动线中,通用和标准零部件的数量可达70％。     

被加热零件在炉内的合理布局

对各种零件、金属型材、管材、金属粉末材料热处理的使用经验和炉子计算的结果表明,工件在炉膛内布局方法的选择,或小零件与金属粉末层厚度的选择,在很多情况下,都将对炉子的技术经济指标产生显著的影响。为了考察这种影响,对已知工作区宽度与长度(即可安置零件的面积)的连续式电炉进行了研究。此时,采用规定的工艺保温时间。众所周知,在装料时总存在着最好的方案。实践中,实际的装料方法常常与最好的方案有所差异,即还存在着使生产率提高的某些潜力。今用二个实例来说明可能的潜力之大小。例1:拖拉机轴在推杆式电炉中作淬火