基于因素分解与总量控制的区域社会经济用水分析

考虑到经济产业结构调整和用水效率控制对社会水循环过程调控的重要性,以江苏沿海开发区域内的盐城市为研究区,根据其社会经济现状与发展计划、水资源开发利用战略与目标、节水型社会建设规划方案等实际情况,采用水资源利用驱动因素分析法和数学规划解析法相结合的手段,建立了纳入驱动因素分解效应量化值的非线性规划模型,计算了2010-2015年研究区基于用水总量控制的社会经济发展规模、产业结构比例及其用水效率的合理方案。最后,根据计算成果,分析了研究区产业结构、用水定额、经济水平与人口规模四个因素对区域用水总量变化的影响。     

Low voltage low power fully differential self‐biased 1.5‐bit quantizer with built‐in thresholds

A new fully differential self‐biased 1.5‐bit flash quantizer with built‐in threshold voltages, suitable for high speed ADCs and low voltage operation, is described. The proposed circuit is very simple, and simulation results in a 65 nm standard CMOS technology demonstrate that, following the suggested design methodology, it is able to achieve low offset, low kickback noise, low metastability probability errors and fast regeneration time with very low power dissipation. Copyright © 2011 John Wiley & Sons, Ltd.     

永磁直线同步电机推力波动约束

由齿槽力、边端力及法向吸力引起的推力波动是影响永磁直线同步电机(PMLSM)动态性能的主要因素。为了实现高速精密直接驱动系统,通过对PMLSM进行有限元分析建模,分析了齿槽力变化规律,利用傅里叶级数拟合得到齿槽力变化曲线;设计了齿槽力电流预测控制模型,对齿槽力引起的推力波动进行补偿;同时设计了扰动观测器对其他因素引起的推力波动进行补偿,进一步削弱了推力波动。最后,通过实验验证PMLSM推力波动补偿控制系统的有效性,补偿后电流和速度的波动都得到了很大改善,能够实现较高精度的直接驱动系统。     

基于RTDS的机电电磁暂态混合实时仿真及其在FACTS中的应用

深入研究了基于实时数字仿真器(RTDS)的混合仿真平台的实现方法,其中包括利用RTDS的自定义工具Component Builder(CBuilder)开发的机电暂态程序与接口模块,并选取了适用于该仿真平台的数据交换时序。提出了利用机电-电磁暂态混合仿真技术进行柔性交流输电系统(FACTS)研究的方法,并在RTDS上搭建有两个静止无功补偿器(SVC)控制母线电压的系统模型,对全系统进行全电磁实时仿真、机电-电磁混合实时仿真、对等值化简后的系统进行全电磁仿真,比较不同SVC组合控制下的仿真结果。验证了混合仿真系统的准确性,阐述了利用未等值大系统开展FACTS应用研究的必要性。可以预见,混合仿真技术在大系统的FACTS研究中具有良好的前景。     

Surface Engineered Carboxymethylchitosan/Poly(amidoamine) Dendrimer Nanoparticles for Intracellular Targeting

Novel highly branched biodegradable macromolecular systems have been developed by grafting carboxymethylchitosan (CMCht) onto low generation poly(amidoamine) (PAMAM) dendrimers. Such structures organize into sphere‐like nanoparticles that are proposed to be used as carriers to deliver bioactive molecules aimed at controlling the behavior of stem cells, namely their proliferation and differentiation. The nanoparticles did not exhibit significant cytotoxicity in the range of concentrations below 1 mg mL^?1, and fluorescent probe labeled nanoparticles were found to be internalized with highly efficiency by both human osteoblast‐like cells and rat bone marrow stromal cells, under fluorescence‐activated cell sorting and fluorescence microscopy analyses. Dexamethasone (Dex) has been incorporated into CMCht/PAMAM dendrimer nanoparticles and release rates were determined by high performance liquid chromatography. Moreover, the biochemical data demonstrates that the Dex‐loaded CMCht/PAMAM dendrimer nanoparticles promote the osteogenic differentiation of rat bone marrow stromal cells, in vitro. The nanoparticles exhibit interesting physicochemical and biological properties and have great potential to be used in fundamental cell biology studies as well as in a variety of biomedical applications, including tissue engineering and regenerative medicine.     

On Multiple Scattering of Radiation by an Infinite Grating of Dielectric Circular Cylinders at Oblique Incidence

A rigorous analytical representation for the multiple scattering coefficients of the fields radiated by an infinite grating of dielectric circular cylinders excited by an obliquely incident plane electromagnetic wave is derived in terms of the “well-known scattering coefficients of an isolated dielectric cylinder at oblique incidence” and “Schlömilch series”. In addition, a generalized sum-integral grating equation is acquired for the multiple scattered amplitude of a cylinder at oblique incidence in the grating in terms of the scattering coefficients of the insulating dielectric circular cylinder at oblique incidence.     

A new electronic tonometer for ocular epipalpebral measurements

A new electronic tonometer is presented in this paper. This is an electromechanical device that has been designed to establish, by means of a fully automatic process, an approximate value of the intraocular pressure (IOP) without the need to be handled by an ophthalmologist. It can be applied on the closed eyelid with no danger for the patient in an easy and simple way. These have been the main prerequisites for the proposed tonometer in order for it to be used in the future in the same way as domestic clinical thermometers are used nowadays. The main benefits obtained with this measurement is a much earlier warning in cases where incipient glaucoma is already carving its silent way to an unexpected future blindness. The tonometer can also be used and has been employed as a research instrument, placed either on the eyelid or on the cornea, and a substantial flow of data on how IOP evolves is obtainable by computerized means. The tonometer is based on a microcontroller device, which is the electronic core of the equipment that manages the user interface, runs the complete test, and shows the final results. This paper describes the design in a stage previous to the "domestic tonometer": a laboratory prototype to obtain physical properties of the eye under a variable static, radial, and epipalpebral force.     

Behavioral modeling, simulation and synthesis of multi-standard wireless receivers in MATLAB/SIMULINK

This paper presents a SIMULINK block set for the behavioral modeling and high-level simulation of RF receiver front-ends. The toolbox includes a library with the main RF circuit models that are needed to implement wireless receivers, namely: low noise amplifiers, mixers, oscillators, filters and programmable gain amplifiers. There is also a library including other blocks like the antenna, duplexer filter and switches, required to implement reconfigurable architectures. Behavioral models of building blocks include the main ideal functionality as well as the following non-idealities: thermal noise, characterized by the noise figure and the signal-to-noise ratio, and non-linearity, represented by the input-referred second-order and third-order intercept points, IIP₂ and IIP₃, respectively. In addition to these general parameters, some block-specific errors have also been included, like oscillator phase noise and mixer offset. These models have been incorporated into the SIMULINK environment making an extensive use of C-coded S-functions and reducing the number of library block elements. This approach reduces the simulation time while keeping high accuracy, which makes the proposed toolbox very appropriate to be combined with an optimizer for the automated high-level synthesis of radio receivers. As an application of the capabilities of the presented toolbox, a multi-standard direct-conversion receiver intended for 4G telecom systems is modeled and simulated considering the building block requirements for the different standards.     

Changes in the volatile composition of red wines during aging in oak barrels due to microoxygenation treatment applied before malolactic fermentation

Microoxygenation is a wine-making technique consisting in the addition of small and controlled amounts of oxygen. This study has examined the effect of this technique on the volatile composition of two red single variety wines during two successive vintages. The microoxygenation treatment was applied at the end of alcoholic fermentation and before beginning malolactic fermentation. Once the microoxygenation treatment had finished, wines were aged in new American oak barrels for 12 months. The results obtained showed that the microoxygenation treatment did not cause significant changes in the varietal and fermentation volatile compounds, however microoxygenation slowed down the extraction of some of the volatile compounds extracted from wood. A varietal and vintage effect was also observed for some of the compounds studied.     

Influence of temperature on continuous high gravity brewing with yeasts immobilized on spent grains

Flavor compounds’ formation and fermentative parameters of continuous high gravity brewing with yeasts immobilized on spent grains were evaluated at three different temperatures (7, 10 and 15 °C). The assays were performed in a bubble column reactor at constant dilution rate (0.05 h⁻¹) and total gas flow rate (240 ml/min of CO₂ and 10 ml/min of air), with high-gravity all-malt wort (15°Plato). The results revealed that as the fermentation temperature was increased from 7 to 15 °C, the apparent and real degrees of fermentation, rate of extract consumption, ethanol volumetric productivity and consumption of free amino nitrogen (FAN) increased. In addition, beer produced at 15 °C presented a higher alcohols to esters ratio (2.2–2.4:1) similar to the optimum values described in the literature. It was thus concluded that primary high-gravity (15°Plato) all-malt wort fermentation by continuous process with yeasts immobilized on spent grains, can be carried out with a good performance at 15 °C.