Transmit/receive modules

This paper begins with a discussion of the microwave functions performed by transmit/receive (T/R) modules for phased-array antenna applications. The paper then addresses performance and cost aspects of semiconductor, packaging, and assembly technologies associated with T/R modules     

高清视频编解码器实现远程呈现

本文介绍了远程呈现技术以及Blackfin处理器在远程呈现解决方案中的应用.     

Changes in the content of health-promoting compounds and antioxidant activity of broccoli after domestic processing.

The effect of water- and steam-cooking on the content of vitamin C, polyphenols, carotenoids, tocopherols and glucosinolates, as well as on the antioxidant activity of broccoli, are reported. Flavonoids, phenolic acids, vitamins C and E, beta-carotene, lutein, and glucosinolates in domestically processed broccoli were quantified using high-performance liquid chromatography (HPLC) methods; total polyphenols were determined with Folin-Ciocalteu reagent. The antioxidant capacities of broccoli extracts were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The results indicated that steam-cooking of broccoli results in an increase in polyphenols, as well as the main glucosinolates and their total content as compared with fresh broccoli, whereas cooking in water has the opposite effect. Steam-cooking of broccoli has no influence on vitamin C, whereas cooking in water significantly lowers its content. Both, water- and steam-cooking of broccoli results in an increase in beta-carotene, lutein, and alpha- and gamma-tocopherols as compared with fresh broccoli. Similar effects of steaming and water-cooking of broccoli on their antioxidant activity were observed.     

Comparison of antiplatelet effects of aspirin, ticlopidine, or their combination after stent implantation

OBJECTIVE: To explore the basis of the gender-based differences in endocrine and surgical findings in patients with prolactinoma (prolactin cell adenoma) as well as in their clinical outcome. MATERIAL AND METHODS: In young or reproductive-age female patients, older women (beyond 40 years of age), and male patients, we systematically studied the following factors: operative and endocrine features (tumor size, invasiveness, preoperative serum prolactin level, and biochemical outcome), specific biologic variables (mitotic index, MIB-1 labeling index, and p27 immunoreactivity), and hormone receptor status (estrogen and progesterone receptor proteins as well as dopamine D2 receptor messenger RNA). RESULTS: Of the various factors assessed, the preoperative prolactin level and MIB-1 labeling index were lower in young female patients in comparison with older female and particularly male patients. Hormone levels were also positively associated with mitotic activity as well as the MIB-1 labeling index. Although invasion was infrequent in microadenomas of young female patients, no statistically significant differences in tumor size or invasiveness were noted among the three patient groups. Absence of differences in invasiveness may, in part, be explained by artifacts of case selection. CONCLUSION: The basis for the observed differences in proliferative activities in tumors of the three study groups is not readily apparent but may reflect differences in the endocrine milieu or the effect of sex steroid hormone receptors, tumoral vascularity, or specific growth factors.     

Improved bounds for displacements at shakedown

A method is proposed for obtaining an upper bound for the displacement which can occur in a structure adapted to a given variable-repeated load. First, the exact formulation of the problem is presented which leads to a problem of optimal control. Then the differential constraints are neglected or replaced by algebraic conditions. The solution of the resulting linear programming problem supplies an upper bound to the exact elastic-plastic deflection. Further approximation can be introduced, if desired, which allows the decomposition of the problem into separate bounds to elastic and plastic parts of displacement.Numerical examples include a two-span continuous beam and a two-storey frame. The first was solved analytically, the second by means of a specially developed computer routine capable of evaluating the displacements at shakedown of arbitrary planar frames or trusses. The results obtained confirm the validity of the small displacement approach.     

A practical /spl Delta/-/spl Sigma/ modulator design method based on periodical behavior analysis

A method for digital delta-sigma modulator design for fractional-N frequency synthesis is presented in this paper. The design method is based on the modulator periodical behavior analysis. The modulator is designed to maintain a constant output signal sequence length which can be controlled for all input dc levels. As a result, the quantization noise power is spread over a known, arbitrarily large number of tones within the Nyquist bandwidth. Therefore, the quantization noise power never concentrates into a few dominant spurious tones. The sequence length is controlled by applying predefined initial conditions and scaling modulator buses. Consequently, the spurious-free range can be controlled as a function of the bus width. Known modulator sequence length defines the time required for full modulator and synthesizer characterization.     

LIDFT-the DFT linear interpolation method

The method of linear interpolation of the discrete Fourier transform (LIDFT) to estimate parameters of a signal consisting of many sinusoidal oscillations, has been presented in the paper. The LIDFT method combines beneficial properties from known procedures of nonlinear interpolation of a spectrum, obtained as a result of DFT and from parametric methods based on the Prony method. The LIDFT algorithm with beneficial numerical properties has been obtained after formulating the assumptions of the LIDFT method, providing a linear matrix equation and following symbolic transformations of this equation. The basic operations involved are the FFT algorithm and linear matrix equation solving procedure. The parametric, linearizing data window together with the method-developed to choose the window parameter allow for effective application of the LIDFT method depending on the examined signal character     

Society of self: The emergence of collective properties in self-structure.

Using cellular automata, the authors show how mutual influences among elements of self-relevant information give rise to dynamism, differentiation, and global evaluation in self-concept. The model assumes a press for integration that promotes internally generated dynamics and enables the self-structure to operate as a self-organizing dynamical system. When this press is set at high values, the self can resist inconsistent information and reestablish equilibrium after being perturbed by such information. A weak press for integration, on the other hand, impairs self-organization tendencies, making the system vulnerable to external information. Paradoxically, external information of a random nature may enhance the emergence of a stable self-structure in an initially disordered system. The simulation results suggest that important global properties of the self reflect the operation of integration processes that are generic in complex systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Graphoepitaxy of High‐Quality GaN Layers on Graphene/6H–SiC

The implementation of graphene layers in gallium nitride (GaN) heterostructure growth can solve self‐heating problems in nitride‐based high‐power electronic and light‐emitting optoelectronic devices. In the present study, high‐quality GaN layers are grown on patterned graphene layers and 6H–SiC by metalorganic chemical vapor deposition. A periodic pattern of graphene layers is fabricated on 6H–SiC by using polymethyl methacrylate deposition and electron beam lithography, followed by etching using an Ar/O₂ gas atmosphere. Prior to GaN growth, an AlN buffer layer and an Al_0.2Ga_0.8N transition layer are deposited. The atomic structures of the interfaces between the 6H–SiC and graphene, as well as between the graphene and AlN, are studied using scanning transmission electron microscopy. Phase separation of the Al_0.2Ga_0.8N transition layer into an AlN and GaN superlattice is observed. Above the continuous graphene layers, polycrystalline defective GaN is rapidly overgrown by better quality single‐crystalline GaN from the etched regions. The lateral overgrowth of GaN results in the presence of a low density of dislocations (≈10⁹ cm⁻²) and inversion domains and the formation of a smooth GaN surface.