洪水水文预报系统

水文预报系统是计算机算法应用于水文预报的一次实践 ,在从产汇流原理出发 ,详细阐述系统结构 ,工作原理及系统特征 ,还对软件的应用及今后开发前景进行了展望 ,随着社会发展和科技进步 ,实施计算机预报系统便于提高预报精度 ,增强水文预报的时效性 ,将使水文预报作用日益显著。     

MCM用氮化铝共烧多层陶瓷基板的研究

通过实验优化AlN(氮化铝)瓷料配方及排胶工艺,对共烧W(钨)导体浆料性能及AlN多层基板的高温共烧工艺进行了研究,并对AlN多层基板的界面进行了扫描电镜分析。采用AlN流延生瓷片与W高温共烧的方法,成功地制备出了高热导率的AlN多层陶瓷基板,其热导率为190 W/(m·K),线膨胀系数为4.6106℃1(RT~400℃),布线层数9层,W导体方阻为9.8 m,翘曲度为0.01 mm/50 mm,完全满足高功率MCM的使用要求。     

A frequency domain ultrasonic model for the pulse-echo transducer response of an arbitrary scatterer in a fluid

A very general model formulation is presented in the frequency domain for the pulse-echo ultrasonic response of an arbitrary scatterer in a fluid. The transducer is modeled as a piston source and the scatterer can be located anywhere in the transducer wavefield. The model is computationally efficient and is shown to agree well with initial experiments.     

Entity-relationship modeling

The entity-relationship (ER) model and its accompanying ER diagrams are widely used for database design and systems analysis. Many books and articles just provide a definition of each modeling component and give examples of the pre-built ER diagrams. As a result, beginners in data modeling have a great deal of difficulty learning how to approach a given problem, what questions to ask in order to build a model, what rules to use while constructing an ER diagram, and why one diagram is better than another. The authors present step-by-step guidelines, a set of decision rules proven to be useful in building ER diagrams, and a case study problem with a preferred answer as well as a set of incorrect diagrams for the problem. These guidelines and decision rules have been successfully used in their beginning database management system course     

预测控制算法的统一格式及其在电加热炉的应用

本文根据常用的两类预测控制算法推出一种新型预测控制算法。并将其应用于一双输入/双输出的力学持久机电加热炉的温度控制系统上,获得了满意的结果:控温精度为±1.5℃/300℃,且适用于非最小相位系统。     

K- and Q-bands CMOS frequency sources with X-band quadrature VCO

Fully integrated 10-, 20-, and 40-GHz frequency sources are presented, which are implemented with a 0.18-/spl mu/m CMOS process. A 10-GHz quadrature voltage-controlled oscillator (QVCO) is designed to have output with a low dc level, which can be effectively followed by a frequency multiplier. The proposed multipliers generate signals of 20 and 40 GHz using the harmonics of the QVCO. To have more harmonic power, a frequency doubler with pinchoff clipping is used without any buffers or dc-level shifters. The QVCO has a low phase noise of -118.67 dBc/Hz at a 1-MHz offset frequency with a 1.8-V power supply. The transistor size effect on phase noise is investigated. The frequency doubler has a low phase noise of -111.67 dBc/Hz at a 1-MHz offset frequency is measured, which is 7 dB higher than a phase noise of the QVCO. The doubler can be tuned between 19.8-22 GHz and the output is -6.83 dBm. A fourth-order frequency multiplier, which is used to obtain 40-GHz outputs, shows a phase noise of -102.0 dBc/Hz at 1-MHz offset frequency with the output power of -18.0 dBm. A large tuning range of 39.3-43.67 GHz (10%) is observed.     

冲击回波法检测隧洞混凝土衬砌厚度

冲击回波法是通过接收、分析在混凝土中传播的回波信号，判断结构混凝土厚度和内部质量的新型无损检测技术。室内试验和工程应用研究表明，该方法为隧洞混凝土衬砌厚度检测提供了一个有效的测试手段。     

Influence of nitrate, ascorbic acid, and nitrate reductase microorganisms on N-nitrosamine formation during Korean-style soysauce fermentation.

Traditional Korean soysauce samples were collected from households in Chinju, Gyeongnam, Korea and analysed for volatile N-nitrosamines. Five of 24 samples contained NDMA (range = 1.6-10.4 micrograms/l) which was the only volatile N-nitroso compound found. Soysauce made from well water contained NDMA more often (4 of 6 samples) than soysauce made from tap water (1 of 18). This suggests that the water source is a determinate in the NDMA content of soysauce, probably due to a higher nitrate content of well water. The source of salt used did not clearly influence NDMA content. Soysauce was prepared in the laboratory using traditional methods but with 0 to 400 mg/l nitrate and in some cases made 6.5 to 65 mM in ascorbic acid and fermented for 120 days. The NDMA content of the samples was positively correlated with increasing nitrate concentration. Nitrate at 400 mg/l resulted in an NDMA content of 203 micrograms/l. Ascorbic acid substantially inhibited NDMA formation. All samples contained large numbers of nitrate reductase-containing organisms (greater than 1 x 10(7) CFU/ml).     

Pseudorandomness of Basic Structures in the Block Cipher KASUMI

The notion of pseudorandomness is the theoretical foundation on which to consider the soundness of a basic structure used in some block ciphers. We examine the pseudorandomness of the block cipher KASUMI, which will be used in the next‐generation cellular phones. First, we prove that the four‐round unbalanced MISTY‐type transformation is pseudorandom in order to illustrate the pseudorandomness of the inside round function FI of KASUMI under an adaptive distinguisher model. Second, we show that the three‐round KASUMI‐like structure is not pseudorandom but the four‐round KASUMI‐like structure is pseudorandom under a non‐adaptive distinguisher model.