设计实例designideas级联低压差稳压器、SMPS抑制纹波，保持效率

降压型SMPS（开关电源）能有效地将未稳压的电源转换为稳定的输出电压。但是．输出端会出现由开关而产生的有害纹波和输入瞬变。如将有噪声的电源加在RF功率放大器上．则会在广播频谱中注入寄生信号或调制噪声。模拟系统工程师与RF系统工程师都青睐传统的低噪声电源设计．它包括一个变压器、整流器和滤波器．后面是一个线性稳压器。一只低压差线性稳压器的低输出噪声和高PSRR（电源抑制比）可以确保干净的电源．不会造成对功率放大器输出的干扰。     

On problem transformability in VLSI

The two basic performance parameters that capture the complexity of any VLSI chip are the area of the chip,A, and the computation time,T. A systematic approach for establishing lower bounds onA is presented. This approach relatesA to the bisection flow, . A theory of problem transformation based on , which captures bothAT ² andA complexity, is developed. A fundamental problem, namely, element uniqueness, is chosen as a computational prototype. It is shown under general input/output protocol assumptions that any chip that decides ifn elements (each with (1+)lognbits) are unique must have =(nlogn), and thus, AT²=(n ²log² n), andA= (nlogn). A theory of VLSI transformability reveals the inherentAT ² andA complexity of a large class of related problems.This work was supported in part by the Semiconductor Research Corporation under contract RSCH 84-06-049-6.     

THE BLUE NILE: POTENTIAL FOR CONFLICT AND ALTERNATIVES FOR MEETING FUTURE DEMANDS

ABSTRACT

Despite nearly a century of water regulation projects on the Nile Basin, today Egypt faces a genuine crisis with respect to water supply. The crisis has been brought on by a combination of drought and greatly increased usage by all riparian nations along the Nile. It is highly probable that Egypt will need to search for new sources of water, reallocate existing water supply and reduce demand simultaneously in order to stave off major water shortfalls. It is unlikely that these measures can be accomplished without both internal and external conflict. This paper describes the current state of water supply and usage in Egypt. Further we examine potential sources of conflict over water allocation decisions. Finally, the paper presents a method for evaluating alternative strategies that could be implemented by Egypt to avoid future conflict.     

Relationships of sonification to music and sound art

The definition of sonification has been reframed in recent years but remains somewhat in flux; the basic concepts and procedural flows have remained relatively unchanged. Recent definitions have focused on the objective the important uses of sonification in terms of scientific method. The full realization of the potential of the field must also include the craft and art of music composition. The author proposes examining techniques of sonification in a two-order framework: direct and procedural. The impact of new technologies and historical roots of that work argues that framing this broad topic should be in terms inclusive of scientific method and craftsmanship and art. The expressive use of sonic time-based data flows needs to be refined and expanded. The unexamined territory of how a broad-based population of listeners on a subjective, as well as objective level needs, have to be included in this new field.     

The MMPI and chronic pain.

112 chronic pain patients (mean age 48.4 yrs) completed the MMPI upon entering either an anesthesiologic or a psychiatric treatment program. Pretreatment MMPI performance was found to be successful in predicting patient outcome an average of 20 mo following treatment, with the K (Test-Taking Attitude), Hypochondriasis, Hysteria, and Masculinity and Femininity scales accounting for most of the variance. The strength of this relationship varied as a function of the measure of outcome and type of treatment received. Substantial MMPI differences were found when Ss with only one part of their body in pain were compared with those with multiple pain complaints. Significant MMPI differences were also found in comparisons based on Ss' sex, type of pain (e.g., head vs back), and type of treatment for which was referred (i.e., psychiatric vs anesthesiologic). Clinical implications of the observed MMPI differences are discussed. Results are seen as demonstrating the value of the MMPI as a clinical and research instrument within this population. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guaranteed cost inequalities for robust stability and performance analysis

In this paper, we formulate robust stability and performance bounds in terms of guaranteed cost inequalities. We derive new guaranteed cost bounds for plants with real structured uncertainty, and we reformulate them as linear matrix inequalities (LMIs). In particular, we obtain a shifted linear bound and a shifted inverse bound, and give LMI forms for a shifted bounded real bound, a shifted Popov bound, a shifted linear bound and a shifted inverse bound. Several examples are used to compare the shifted bounds with their unshifted counterparts and to make comparisons among these new bounds and vertex LMI bounds. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis and characterization of one-dimensional flat ZnO nanotower arrays as high-efficiency adsorbents for the photocatalytic remediation of water pollutants

We report on facile fabrication of 1-D flat ZnO nanotower arrays on various substrates, including a metal, a semiconductor and an insulator. The nanotowers have a unique flat basal section near the substrate and taper in stages to wire-like at the tip. Electron microscopy and X-ray photoelectron spectroscopy are used to characterize these new nanostructures, revealing that their morphologies are significantly influenced by reaction temperature. A qualitative formation mechanism is proposed based on the experimental observations. A proof-of-concept demonstration shows that the ZnO nanotower arrays are highly effective at adsorbing and subsequently photo-remediating a model pollutant (Eosin B) from water. These observations could promote new applications of photocatalytic adsorbents for wastewater treatment utilizing oxide semiconductor nanostructures.     

Binding of harvested bacterial exopolymers to the surface of calcite

Biologically produced exopolysaccharides (EPS) affect calcite dissolution and precipitation. In this study, natural alkaliphilic microbial isolates were collected from biofilms on historic limestone. The isolates were screened for their ability to produce significant quantities of EPS in cultures. The most productive isolates were identified by 16S rRNA sequence analysis as a close relative of Bacillus cereus. EPS with different chemical structures were harvested from the isolates. Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of binding by the harvested EPS to calcite. The binding was described by a Langmuir adsorption isotherm. Characterization of the EPS showed that binding strength to calcite depended on the chemical nature of the polymer.     

Water Uptake by NaCl Particles Prior to Deliquescence and the Phase Rule

Using an environmental transmission electron microscope (ETEM), we show that a significant amount of water, far exceeding the multilayers caused by surface adsorption, is reversibly associated prior to deliquescence with substrate-supported NaCl particles (dry diameters of ～ 40 nm to 1.5 μ m; ～ 18°C). We hypothesize that the water is present as an aqueous solution containing dissolved Na and Cl ions. Water uptake occurs at relative humidities (RH) as low as 70%, and the resulting liquid layer coating the particles is stable over extended times if the RH is held constant. We exposed CaSO ₄ and CaSO ₄ · 2H ₂ O particles to elevated RH values in the ETEM to show that chemically nonspecific condensation of gas-phase water on the TEM substrate does not explain our observations. Furthermore, damage to the NaCl surface induced by the electron beam and small fluctuations in RH do not seem to contribute to or otherwise affect water uptake. We have similar observations of water association for other alkali halide particles, including NaBr and CsCl, prior to deliquescence. To explain the observations, we derive the phase rule for this geometry and show that it allows for the coexistence of liquid, solid, and vapor for the binary NaCl/H ₂ O system across a range of RH values. The derivation includes the effects of heterogeneous pressure because of the Laplace-Young relations for the subsystems. Furthermore, in view of the lever rule and the absence of similar observations for free-floating pure NaCl aerosol particles, we hypothesize that the surface energy necessary to support these effects is provided by sample-substrate interactions. Thus, the results of this study may be relevant to atmospheric systems in which soluble compounds are associated with insoluble materials.