On the cyclotron maser instability in a waveguide

Journal of Infrared, Millimeter, and Terahertz Waves - The cyclotron maser instability is conventionally treated as a pure electromagnetic instability(5). Waveguide modes can'be equivalent to...     

DMA-80 直接测汞仪测定四种中药中汞含量

目的 用DMA-80直接测汞仪对山楂、金银花、白芍、中槐提取物四种中药的汞含量进行测定。方法 利用DMA-80直接测汞仪对四种中药的汞含量进行测定, 样品无需做离线的湿化消解或复杂前处理, 可全自动直接进样。结果 样品回收率在90.1%~103.4%之间, RSD为2.0%~3.0%。结论 该方法无需前处理, 简便快捷, 可得到满意的测定结果, 适用于中药中汞含量的测定。     

Adaptive control of system involving complex hysteretic nonlinearities: a generalised Prandtl–Ishlinskii modelling approach

In this article an adaptive control approach is proposed for a class of nonlinear systems preceded by unknown hysteretic nonlinearities, which is described by a generalised Prandtl–Ishlinskii (P-I) model. The main feature is that the generalised P-I hysteresis model is counted in the controller design without constructing a hysteresis inverse. The developed controller guarantees the global stability of the system and tracking a desired trajectory to a certain precision is achieved. The effectiveness of the proposed control approach is demonstrated through simulation example.     

Robust output tracking control for the systems with uncertainties

A new robust tracking control is proposed for the minimum phase dynamical systems with parameter uncertainties and unmatched disturbance, where only the input-output measurement of the system is employed. The system parameters may vary slightly around their corresponding nominal values. The disturbance is assumed to be bounded. However, the upper and lower bounds are unknown. First, the frame of the control law is presented. Then, a special bounded signal is generated by the disturbance and the model uncertainties are estimated by a new non-linear method, where the upper and lower bounds of the special signal are adaptively updated online. Finally, the robust tracking control is synthesized by using the estimate of the special signal. The output tracking error can be made as small as necessary by choosing the design parameters. The attraction of the proposed method lies in its robustness to uncertainties and its ease of implementation. Example and simulation results are presented to show the effectiveness of the proposed algorithm.     

Exploring problem solving patterns and their impact on learning achievement in a blended learning environment

Blended learning, thoughtfully combining the best elements of online and face-to-face education, is likely to emerge as the predominant teaching model of the future. In this paper, we present a blended learning environment combining mobile learning, web-based learning, and classroom teaching to provide realistic, practical opportunities for learners and teachers to engage in problem solving activities. The purpose of this study was to explore problem solving patterns and their impact on learning achievement in a blended learning environment. Through quasi-experimental instruction, we collected all of the data of the learning processes from 34 students in a blended learning environment using classroom instruction, mobile and web scenarios. By combining cluster analysis and content analysis, we were able to identify three groups with distinct characteristics: the hybrid-oriented group, the technology-oriented group, and the efficiency-oriented group. Learners in the hybrid-oriented group used the classroom, mobile and web scenario almost equally. They displayed a regular manner in following the instructor’s teaching procedure, and tended to passively accept whatever the teacher said. Students in the technology-oriented group spent most of their time using mobile and web technologies but they revealed superficial problem solving abilities such as a lack of understanding and planning. The efficiency-oriented group was characterized by the efficient monitoring of learning processes. It was more task-oriented and performed better than the other two groups.     

Intelligent patent recommendation system for innovative design collaboration

Patents' search is increasingly critical for a company's technological advancement and sustainable marketing strategy. When most innovative designs are created collaboratively by a diverse team of researchers and technologists, patent knowledge management becomes time consuming with repeated efforts creating additional task conflicts. This research develops an intelligent recommendation methodology and system to enable timely and effective patent search prior, during, and after design collaboration to prevent potential infringement of existing intellectual property rights (IPR) and to secure new IPR for market advantage. The research develops an algorithm to dynamically search related patents in global patent databases. The system clusters users with similar patent search behaviors and, subsequently, infers new patent recommendations based on inter-cluster group member behaviors and characteristics. First, the methodology evaluates the filtered information obtained from collaborative patent searches. Second, the system clusters existing users and identifies users' neighbors based on the collaborative filtering algorithm. Using the clusters of users and their behaviors, the system recommends related patents. When collaborative design teams are planning R&D policies or searching patents and prior art claims to create new IP and prevent or settles IP legal disputes, the intelligent recommendation system identifies and recommends patents with greater efficiency and accuracy than previous systems and methods described in the literature.     

Designing dynamic English: a creative reading system in a context-aware fitness centre using a smart phone and QR codes

Abstract

This article describes the design and development of a context-aware ubiquitous learning (u-learning) system for users to increase fitness-related reading comprehension in a fitness centre. With the use of mobile devices and sensing technologies, practitioners and researchers of ICT and ubiquitous computing (ubicomp) are paying attention to the planning and use of u-learning components to provide users more interactions with authentic learning objects in a real context. Meanwhile, English for specific purposes (ESP) with interaction design has been a focus in recent years; however, few ESP practitioners and researchers have explored fitness-related English with ubicomp. All of the users were satisfied with the use of the smart phones and scanning of QR codes on the machines in the fitness centre to develop their reading comprehension of fitness-related English. Finally, a learning design model for Fitness English reading with u-learning components was developed and elaborated from designers' perspectives.     

Adaptive control of a class of nonlinear systems with nonlinearlyparameterized fuzzy approximators

Recently, through the use of parameterized fuzzy approximators, various adaptive fuzzy control schemes have been developed to deal with nonlinear systems whose dynamics are poorly understood. An important class of parameterized fuzzy approximators is constructed using radial basis function (RBF) as a membership function. However, some tuneable parameters in RBF appear nonlinearly and the determination of the adaptive law for such parameters is a nontrivial task. In this paper, we propose a new adaptive control method in an effort to tune all the RBF parameters thereby reducing the approximation error and improving control performance. Global boundedness of the overall adaptive system and tracking to within a desired precision are established with the new adaptive controller. Simulations performed on a simple nonlinear system illustrate the approach     

程序规范自动检测与修正系统ADRS的研究

文中介绍了一个程序规范自动检测与修正系统ＡＤＲＳ的理论模型,在开放逻辑的思想基础上,文中提出了一种自动修正模型,并试图对李未提出的３个问题给出解决方案。作为对第１个问题的解决,作者提出了一种刻画程序规范重要性程度的全序结构,克服了加标记的二分法地粗糙性。作为对第２个问题的解决,作者提出了修正函数的定义和Ｒ－计算模型,并证明了该模型满足修正函数的要求。作为对第３个问题的解决,作者提出了Ｔ－修正函数的     

A spur-reduction technique for a 5-GHz frequency synthesizer

A spur-reduction technique is presented to achieve low reference spurs for a 5-GHz frequency synthesizer. A dual-path control scheme incorporated with a pair of the proposed smoothed varactors reduces the gain of voltage-controlled oscillator to less than 15 MHz/V, attenuates the spurious tones, and shortens the simulated settling time by 56%. In, addition, a digital frequency-calibration circuit is used to enlarge the tuning range to overcome process variations. A 5-GHz frequency synthesizer has been fabricated for verification in a 0.18-/spl mu/m CMOS process. It exhibits phase noise of -79 and -113 dBc/Hz at 10-kHz and 1-MHz offset, respectively. The reference spur level of -74 dBc is achieved by using a second-order loop filter. The overall tuning range is 16.3% and power consumption is 36 mW from a 1.8-V supply. The total switching time including digital frequency calibration takes no more than 110 /spl mu/s.