Effect of the frequency and temperature on the complex impedance spectroscopy (C–V and G–V) of p-ZnGa2Se4/n-Si nanostructure heterojunction diode

X-ray diffraction pattern and AFM results confirm the nanostructure of p-ZnGa₂Se₄/n-Si. The unit cell lattice parameters, the crystallite size L, the dislocation density δ, and the main internal strain ε were calculated. The temperature and frequency-dependent electrical characteristics of the Al/p-ZnGa₂Se₄/n-Si/Al heterojunction diode (HJD) have been investigated to determine the interface states which are responsible for the non-ideal behavior of the characteristics of the diode. The capacitance–voltage (C–V), conductance–voltage (G–V), and series resistance–voltage (R _s–V) characteristics of the diode have been analyzed in the frequency range of 5 kHz–1 MHz and temperature range of 303–423 K. The interfaces states of the diode were determined using conductance–voltage technique. The interface state density profile for the diode was obtained as a function of temperature and frequency. The values of the built-in potential V _bi, the doping concentration N _d and the barrier height φ _b(C–V) of the diode were calculated at different temperatures and frequencies. Our experimental results revealed that both the series resistance and interface state density values must be taken into account in studying the impedance spectroscopy of HJD to stand up their performance for electronic applications characteristics.     

XML compression techniques: A survey and comparison

XML has been acknowledged as the defacto standard for data representation and exchange over the World Wide Web. Being self describing grants XML its great flexibility and wide acceptance but on the other hand it is the cause of its main drawback that of being huge in size. The huge document size means that the amount of information that has to be transmitted, processed, stored, and queried is often larger than that of other data formats. Several XML compression techniques has been introduced to deal with these problems.In this paper, we provide a complete survey over the state-of-the-art of XML compression techniques. In addition, we present an extensive experimental study of the available implementations of these techniques. We report the behavior of nine XML compressors using a large corpus of XML documents which covers the different natures and scales of XML documents. In addition to assessing and comparing the performance characteristics of the evaluated XML compression tools, the study also tries to assess the effectiveness and practicality of using these tools in the real world. Finally, we provide some guidelines and recommendations which are useful for helping developers and users for making an effective decision towards selecting the most suitable XML compression tool for their needs.     

Comments on "Linear function observer for linear discrete-time systems"

Two alternative systematic algorithms are suggested to compute the matrixTnecessary to design a minimum-time linear function observer. The simplicity of these algorithms gives mole insight to the understanding of the observer structure. Furthermore, the computational effort required to obtain the matrixJis spared.     

Carrier-Sense Protocols for Packet-Switched Smart Antenna Basestations

Studies have considered the possible performance improvements when smart antennas are used in packet-switched data networks [1, 2, 3]. This work has included systems which operate using various ALOHA, polling, and reservation-based protocols. Recently however, a single-beam system was described which uses a smart antenna basestation to communicate with a set of stations using a carrier sense multiple access (CSMA) protocol [4]. In this system, performance improvements are obtained by having the antenna dynamically point pattern nulls in the direction of interfering stations, thus reducing the effects of channel collisions.In this paper, we consider the performance of CSMA systems where stations access a smart antenna basestation using multibeam SDMA. As in other SDMA networks, the objective is for the basestation to transmit or receive multiple packets simultaneously. A basic CSMA/SDMA protocol is proposed for this purpose. Note that unlike conventional systems, the CSMA objective of isolating a single successful transmission is not desirable. Instead, our protocol uses carrier-sensing to synchronize various smart antenna operations. In this paper we also present a more sophisticated CSMA/SDMA protocol which incorporates novel basestation/portable signalling which mitigates the effects of hidden stations. The proposed mechanism takes into account the transient connectivity of such systems using the coherence time of the channel as an operating parameter. The performance of these systems is characterized and compared using analytical throughput/capacity models and mean delay simulations. It is shown that when hidden station effects are present, the capacity performance of the more sophisticated protocol may be much higher than that of the basic version.     

Elevated alpha-fetoprotein secondary to Hodgkin's lymphoma

We describe the case of a 26-year-old man with an elevated level of alpha-fetoprotein who had no evidence of intragonadal or extragonadal germ cell tumor. The patient was found to have Hodgkin's lymphoma within an anterior mediastinal mass. We review the significance of elevated alpha-fetoprotein levels and discuss the clinical relevance of this unusual presentation of a possible primary Hodgkin's lymphoma.     

Poly(dimethylsiloxane) coatings for controlled drug release. II. Mechanism of the crosslinking reaction in emulsion

Earlier work focused on the crosslinking of hydroxyl‐terminated poly(dimethylsiloxane) (PDMS) particles in a stable latex suitable for spraying onto drug tablets, and established the conditions for eliminating the usual toxic catalysts that would be unacceptable in such pharmaceutical coating materials. Use of these coatings for controlling the rate of release of a drug, however, requires a better understanding of their properties and thus clarification of the mechanism through which the crosslinking occurs. The present study approaches this goal by documenting the effects of anionic, cationic, and nonionic surfactants at various concentrations, and in acidic, neutral, or basic media. FTIR spectroscopy was used to monitor the transportation of crosslinker from the water phase into the hydrophobic PDMS phase. The results suggest a possible mechanism for the crosslinking in sufficient detail to be used to optimize the coatings for drug‐release applications. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2186–2194, 2004     

Angiotensin-converting enzyme inhibition and antioxidant activity of commercial dairy starter cultures

Food Science and Biotechnology - In this study, skim milk fermented with 14 commercial dairy starters were evaluated for their proteolysis ability, angiotensin I-converting enzyme (ACE)-I, and...     

DNA quantitation of intraepithelial neoplasia and invasive carcinoma of the prostate

Head-restrained rats were conditioned to perform a CNV task: to press a lever in response to an imperative auditory stimulus (S2) given 1.5 sec after a warning stimulus (S1) for a drop of jelly food. With an electrode on the surface of the forelimb cortex, (1) sharp wave complexes immediately after S1 and S2, and (2) a negative slow potential (SP) between S1 and S2, on which early and late components were discernible, were recorded in association with performance of this task. With the electrode at a depth of 2 mm in the same cortical area, the corresponding field potential showed a long-lasting positive shift in addition to the components of the surface potential. These monopolar recordings were obtained with respect to a common reference at the frontal sinus. The surface-minus-depth potential (the transcortical potential), consequently, showed a surface-negative tonic wave, confirming Pirch's report (1980). During extinction of this conditioning, the SP between S1 and S2 disappeared, while the sharp waves following S1 and S2 remained with little modification, suggesting that the sharp waves are a kind of evoked potential (EP) elicited by the stimuli. Recording from 5 surface electrodes set in an array over the left hemisphere contralateral to the used forelimb during development of the conditioning revealed not only a spatial distribution of the SP but also a transition of the potentials. As the conditioning progressed, the negativity of the early SP component tended to increase, while that of the late component tended to decrease and was confined to the sensorimotor cortex.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of 1-naphthaleneacetic acid on the seed,protein, oil,and fatty acids of egyptian cotton

The effects of 1-naphthaleneacetic acid (NAA) applied at various levels and times on yield, seed index, protein and oil content and fatty acid compositions of cotton plants seeds were studied. NAA increased the seed yield/plant and the seed, protein, and oil yields/ha compared to the control. A level of 20 ppm proved best for yield. Most NAA treatments significantly increased the seed index, but only slight increases in seed protein content were recorded. Increases in the amount of seed oil was moderate, with fluctuation that was due to treatment. NAA generally caused decreases in saturated fatty acids that were associated with increases in unsaturated fatty acids. One treatment proved to be more effective than multiple treatments. Palmitic acid and linoleic acid were the most abundant saturated and unsaturated fatty acids, respectively.     

Scalable Nanoshaping of Hierarchical Metallic Patterns with Multiplex Laser Shock Imprinting Using Soft Optical Disks

Large‐area patterning of metals in nanoscale has always been a challenge. Traditional microfabrication processes involve many high‐cost steps, including etching and high‐vacuum deposit, which limit the development of functional nanostructures, especially multiscale metallic patterns. Here, multiplex laser shock imprinting (MLSI) process is introduced to directly manufacture hierarchical micro/nanopatterns at a high strain rate on metallic surfaces using soft optical disks with 1D periodic trenches as molds. The unique metal/polymer layered structures in inexpensive soft optical disks make them strong candidates of molds for MLSI processes. The feasibility of MLSI on hard metals toward soft molds is studied using theoretical simulation. In addition, various types of hierarchical structures are fabricated via MLSI, and their optical reflectance can be modulated via a combination of depth (laser power density), width (types of molds), and angles (rotation between molds). The optical properties have been studied with surface plasmon polariton modes theory. This work opens a new way of manufacturing hierarchical micro/nanopatterns on metals, which is promising for future applications in fields of plasmonics and metasurfaces.