A Comparison of Methods for Polyuronide Methoxyl Determination

A comparison was made between three basic methods for determining methoxyl (OMe) groups in a polyuronide, viz., step-wise oxidation-reduction initiated by hydriodic acid, neutralization of de-esterified carboxyl groups with potassium hydroxide, and direct combustion of methanol by gas chromatography. Accuracy and precision of the methods were ascertained by analyzing methyl fuorate. All the methods were accurate. The neutralization and gas chromatographic methods had major advantages of simplicity and shortness of time of completion over the hydriodic acid/bromine method. Dimethylsulfoxide in the the saponification medium had no special effect.     

Cr-Si粉末冶金工艺及其物理-力学性能

粉末冶金制作法主要有热压(HP)、热等静压(HIP)及常压烧结(Sinter)三种.采用热压及热等静压法可以很容易地得到高致密化的高温金属硅化物,但若要进行大尺寸的产品烧结,必须提升生产设备的规格和能力,例如加大热压机力吨位、扩大热压炉腔体等,致使设备投资及生产成本相对昂贵.所以大部分厂商宁可采用常压烧结法,虽然该法的高致密化工艺条件不易控制,却因可以制作大尺寸金属硅化物,加上设备投资及生产成本相对降低,使许多大厂已投入相当大的人力和物力在开发此工艺.该文作者试用不同真空烧结温度,造成Cr-Si合金粉末烧结性质的差异,探讨稳定而可大量生产的可行性;并通过对温度的控制,来改善Cr-Si的物理性质与力学性质.结果表明,提高烧结温度会使Cr-Si合金产生部分液相烧结的现象,从而使孔隙率显著下降;但显微结构也随之有偏析与晶粒粗化的现象.     

综合先进技术的交通噪音评估(一)-以立体地理资讯系统为基础的区域噪音模型

为了解、组织及整理整个香港区域的道路交通噪音资料,从而确定、量化及分折交通噪音的严重性,再鉴定相关的噪音缓解措施,香港环境保护署综合了数种先进的技朮,包括地理信息系统、大型的电脑噪音模型、立体影像技朮等,自行开发了一套以立体地理资讯系统为基础的区域噪音模型。从这个系统和模型计算出来的交通噪音地图,加上利用地理信息系统軟件、人口分布的资料库和统计学方法的帮助,评估了整个城市总共有多少居民在那些区域受着多少交通噪音的影响。这些结果可以分析交通噪音的问题,继而决定未来噪音缓解设施及制定综合的计划,以应付这噪音问题。     

Feed/Seed比值对好氧生物处理效率的影响

好氧生物反应器的进料物（Feed）是经厌氧作用的消化污泥，而其接种体（Seed）是活性污泥。主要研究了四种Feed／Seed比值（1：0，3：1，1：1和0：1）对好氧生物处理效率的影响。对于Feed／Seed比值为1：0和0：1而言，污泥的TSS和VSS的去除率很低。而另外两种比值的实验结果表明，TSS和VSS的去除率均随Feed／Seed比值的增加而增加。对于Feed／Seed比值为3的生物反应器，28天的TSS和VSS的去除率分别达到了49％和50％。并且TSS和VSS的降解服从一级反应动力学。动力学降解常数（k）也随Feed／Seed比值的增加而增加。而且VSS的去除率略高于TSS。另外，硝化反应的发生导致好氧生物反应器中的硝酸根离子浓度的增加和pH的降低。     

ILC for non-minimum phase system

In this paper we propose a design method of an iterative learning controller (ILC) for a non-minimum phase (NMP) system by model-matching theory. The ILC consists of two learning filters acting on both the previous input signal and the previous error signal. To design the learning filters, we convert the convergence condition of the ILC into the model-matching problem and get the stable and proper learning filter by solving the Nevanlinna's algorithm. To show the usefulness of the proposed algorithm, some design examples are included.     

Adaptive tracking system for a manoeuvring target using images with correlated noises

An effective scheme is proposed for estimating the state parameters of a manoeuvring target from a noisy image sequence, providing the sequence contains correlated noises and the trajectory of the target is disturbed by an unknown acceleration. For the correlated noises, a first-order difference operator is applied to the original image sequence to generate an artificial measurement sequence with only uncorrelated white noises. For the unknown acceleration, a Kalman filter augmented by a semi-Markov process and the bayesian theory is applied to form an adaptive filter. In the proposed tracking system, the filter first generates an artificial measurement at each sampling time from the observation. It then utilizes an artificial measurement sequence up to the current time instance to predict the a posteriori probability of each possible acceleration state. The weighted average of acceleration, where the weight is the a posteriori probability, is applied to derive the optimal estimates of the state parameters. Several computer simulations with external force applied at unknown times are performed to demonstrate the applicability and superiority of the proposed system.     

Multipurpose controller synthesis in discrete LQG optimal systems

This paper presents a design algorithm to synthesize a discrete-time linear-quadratic-gaussian (LQG) optimal controller that simultaneously ensures (i) input–output decoupling; (ii) pole and zero placement; and (iii) robust stability in the presence of plant perturbation. Two weighting matrices Q(Z) and R(Z) of the quadratic cost functional are shaped to synthesize an optimal controller to achieve the stated design goals.     

Collapse behavior evaluation of hybrid thin-walled member by stacking condition

The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, the energy absorbing members should absorb collision energy sufficiently but for the environmentally-friendly aspect, the vehicle structure must be light weight in order to improve the fuel efficiency and reduce the tail gas emission. Therefore, the light weight of vehicle must be achieved in a securing safety status of crash. An aluminum or carbon fiber reinforced plastics (CFRP) is rep...