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This paper introduces the common ways for pepper decorticating and the current status of their applications and effects. According to the actual needs of market development and our analysis on peppers’ physical structures, three kinds of decorticating principles are put forward which include spiral, frictional and centrifugal decorticators and their mechanisms and advantages are analyzed in detail respectively, which will be highly instructive to the research of pepper decorticating equipment.

Existing pepper fruit peeling machine for peeling incomplete, improper peeling force, pit protective film damaged, lead to a high impurity rate, pit crushing, unsatisfactory color and other issues. In order to solve these problems, manufacturing pepper fruit preprocessing machine based on analysis of pepper machining process. The machine achieves pepper fruit surface damaged by differential principle, work in with pepper peeling machine to peel completely.

Programmable constant-temperature/humidity test chamber owned by Natural Fiber Laboratory, Institute of Agricultural Machinery, Chinese Academy of Tropical Agricultural Sciences, is adopted to analyze undegummed pineapple fibers’ moisture absorptions. Study and analysis on moisture absorptions, moisture-absorption isothermsand moisture-absorption isohumes with constant temperature and inconstant humidities are carried out and the results show that fibers’moisture absorptions present roughly a regularity of such three stages as 0~20%, 20~80% and 80~100% (RH). In low-moisture stage, moisture absorption rates are higher; in middle-moisture stage, they level off; in high- moisture stage, moisture absorption rates are the highest. Fibers’moisture absorption amounts decrease along with temperature rise; but under the condition of high humidity, they increase along with temperature rise and also increase along with humidity rise. Study on undegummed pineapple fibers’moisture absorptions may provide theoretical basis for undegummed pineapple fiber preservation and textile processing in some special industries.

This study tests the antimicrobial properties of pineapple leaf fiber. Scanning electron microscopy (SEM), infrared analysis (IR) and other test methods were used to examine the microcosmic morphologies of pineapple leaf fiber. As the pineapple leaf fiber adhesive content reduce fiber antibacterial. Adhesive content 54% of fiber to escherichia coli and staphylococcus aureus antibacterial value is maximum. With further reduce fiber adhesive content, fiber antimicrobial declined obviously. The results indicate that the anaerobic bacteria can’t survive in the inside of pineapple leaf fiber where exist a large specific surface-area, lots of holes and Voids, and much oxygen. Pineapple leaf fiber contains a lot of phenols and their derivatives which are effective natural bacteria resistant materials and inhibit the metabolism and physiology of bacillus and other microorganism,break the structure of germ, and repress the generation of bacillus until the death of germ.Moreover, the existence of a small amount of cannabinol is adequate to kill the microorganisms.

To determine the the fiber fineness in different parts of the old and young leaves. the pineapple leaf fiber of comte de paris was used as raw material, The results showed that, the length of fiber extracted from the old leaves of comte de paris pineapple ranged from 70 cm to 90 cm, and the average fiber fineness of the the tip and root were 14.13 dtex and 18.50 dtex, respectively. While the length of fiber extracted from the young leaves of comte de paris pineapple ranged from 45 cm to 65 cm, and the average fiber fineness of the the tip and root were 13.09 dtex and 15.03 dtex, respectively. Variance analysis reveals that the fiber fineness of root and tip in the old pineapple leaf showed significant difference (P<0.05) in comte de paris pineapple.

To determine the the fiber fineness in different parts of the old and young leaves. the pineapple leaf fiber of smooth cayenne was used as raw material, The results showed that, the length of fiber extracted from the old leaves of smooth cayenne pineapple ranged from 80 cm to 100 cm, and the average fiber fineness of the the tip and root were 14.40 dtex and 18.53 dtex, respectively. While the length of fiber extracted from the young leaves of smooth cayenne pineapple ranged from 50 cm to 70 cm, and the average fiber fineness of the the tip and root were 13.27 dtex and 14.77 dtex, respectively. Variance analysis reveals that the fiber fineness of root and tip in the old pineapple leaf showed significant difference (P<0.05) in smooth cayenne pineapple.

Annealing behavior of thin gate oxide after quasi-breakdown (QB) has been investigated. The result implies that the QB leakage current is consisted of two components: the enhanced tunneling due to locally thinned oxide at interface-damaged region and the conduction through a shortening path. The change of leakage current during annealing is a competitive process of changes of these two components - the recovery of interface damage and the expansion of the shortening path in bulk oxide. A unified model is proposed to explain the mechanism of conduction in QB.

n‐Type GaN thin films grown by metal‐organic chemical vapour deposition (MOCVD) were studied using photoluminescence (PL), photoreflectance (PR) and Raman scattering. In the PL spectra, the peak position of the band‐edge transition shifts to the red side monotonically with increasing doping concentrations. It may be explained theoretically in terms of many‐body effects, namely the renormalization of the bandgap. In the meantime, the line width of the PL peak is increased monotonically with the doping concentration. The luminescence line broadening can be modelled in terms of potential fluctuations caused by the random distribution of doping impurities. In the PR spectra the magnitude decreases monotonically with increasing doping concentration. This result can be explained by a simple model based on an assumption that low‐density surface states exist in the surface of GaN. In the Raman scattering spectra, both A1(LO) mode and E2mode were observed in the back scattering configuration. The A1(LO) mode shifted towards the high‐frequency side and broadened with an increase in carrier concentration. This phenomenon can be interpreted by the LO phonon being coupled to the overdamped plasmon in GaN. Copyright © 1999 John Wiley & Sons, Ltd.

Semi-transparent Au-Schottky contacts on n-GaN were fabricated and studied by room-temperature photoreflectance spectroscopy. A significant difference was observed in the photoreflectance spectra before and after the evaporation of Au-Schottky contacts. This can be interpreted due to the formation of Schottky barrier at the interface between Au and GaN. Furthermore, for the higher doping sample, Franz-Keldysh oscillations were observed in the photoreflectance, which allowed the accurate determination of Au-Schottky barrier height on GaN.

n-Type GaN thin films grown by metal-organic chemical vapour deposition (MOCVD) were studied using photoluminescence (PL), photoreflectance (PR) and Raman scattering. In the PL spectra, the peak position of the band-edge transition shifts to the red side monotonically with increasing doping concentrations. It may be explained theoretically in terms of many-body effects, namely the renormalization of the bandgap. In the meantime, the line width of the PL peak is increased monotonically with the doping concentration. The luminescence line broadening can be modelled in terms of potential fluctuations caused by the random distribution of doping impurities. In the PR spectra the magnitude decreases monotonically with increasing doping concentration. This result can be explained by a simple model based on an assumption that low-density surface states exist in the surface of GaN. In the Raman scattering spectra, both A1(LO) mode and E2 mode were observed in the back scattering configuration. The A1(LO) mode shifted towards the high-frequency side and broadened with an increase in carrier concentration. This phenomenon can be interpreted by the LO phonon being coupled to the overdamped plasmon in GaN. Copyright © 1999 John Wiley & Sons, Ltd.

Intervalley ?-Xdeformation potential constants (IVDP's) have been calculated by first principle pseudopotential method for the III-V zincblende semiconductors A1p, A1As, A1Sb, Gap, GaAs, GaSb, InP, InAs and InSb. As a prototype crystal we have also carried out calculations on Si. When comparing the calculated IVDP's of LA phonon for Gap, InP and InAs and LO phonon for A1As, A1Sb, GaAs, GaSb and InSb with a previous calculation by EPM in rigid approximation, good agreements are found. However, our ab initio pseudopotential results of LA phonon for A1As, A1Sb, GaAs, GaSb and InSb and LO phonon for Gap, InP and ZnAs are about one order of magnitude smaller than those obtained by EPM calculations, which indicate that the electron redistributions upon the phonon deformations may be important in affecting ?-Xintervalley shatterings for these phonon modes when the anions are being displaced. In our calculations the phonon modes of LA and LO at Xpoint have been evaluated in frozen phonon approximation. We have obtained, at the same time, the LAX and LOX phonon frequencies for these materials from total energy calculations. The calculated phonon frequencies agree very well with experimental values for these semiconductors.

We successfully applied the Green function theory in GW approximation to calculate the quasiparticle energies for semiconductors Si and GaAs. Ab initiopseudopotential method was adopted to generate basis wavefunctions and charge densities for calculating dielectric matrix elements and electron self-energies. To evaluate dynamical effects of screened interaction, GPP model was utilized to extend dieletric matrix elements from static results to finite frequencies. We give a full account of the theoretical background and the technical details for the first principle pseudopotential calculations of quasiparticle energies in semiconductors and insulators. Careful analyses are given for the effective and accurate evaluations of dielectric matrix elements and quasiparticle self-energies by using the symmetry properties of basis wavefunctions and eigenenergies. Good agreements between the calculated excitation energies and fundamental energy gaps and the experimental band structures were achieved.

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(1)A 2D tunneling model is developed to assess the tunneling reduction in cylindrical gate (CG) in nanowire (NW) MOSFETs with radius Rs, comparing with the planar double gate (PG-DG) transistor with Tsemi=2Rs and same dielectric thickness Tox. High-k gate dielectric is more effective to suppress the gate leakage in NW than in PG transistors, (2) the carrier quantization induced tunneling barrier reduction is larger in NW than in DG-PG transistors. The gate tunneling rate is finally determined by combining two effects of (1) and (2). Different results for Si, Ge, and InGaAs NWs are demonstrated, (3) comparing with PG transistor, the overdrive gate voltage in NW transistor can be reduced significantly. At the same time evolution of dielectric charge generation, the NW transistor lifetime can be greatly extended.

It is widely recognized that recovery during measurement delay seriously misleads the BTI phenomena. We have developed a modified Charge Pumping (MCP) method to measure the interface trap generation under stress with negligible recovery during measurement delay. The method simply extends the inversion level Vinv of the CP pulse to the stress voltage and keeps the duty cycle of Vinv as large as possible, therefore the stress is almost "on" during measurement. For the first time, we developed a diagram representation of CP process and used to the physical analysis for the contribution and exclusion of slow oxide charge contribution in the CP current of this MCP method. Using this MCP method and the fast pulsed Id-Vg method (FPM) we developed in the past, we systematically investigate and compare the NBTI degradation of p-MOSFETs with thermal (TNO) and plasma (PNO) nitrided SiON gate dielectrics with the same nitrogen surface concentration. We also systematically measure the interface trap degradations in four configurations of NBTI and PBTI stresses for both n-MOSFETs and p-MOSFETs. The following results are achieved: (1) The oxide charge induced degradation in TNO SiON devices is several times larger than those in PNO devices under the same stress condition, due to the larger charge moment in the gate dielectrics of the TNO devices. (2)

We summarize our recent investigation on the NBTI degradation in p-MOSFETs with SiON gate dielectric. (1)For the slow NBTI component, we show evidence that the degradation and recovery is due to interface trap Nit generation and passivation. Nit measured by conventional CP and DCIV methods is underestimated due to passivation under measurement; (2) Due to the degradation during initial threshold voltage measurement, the existing (slow) on-the-fly measurement distorts (overestimates) the slope and induces a kink at early stress time in the Log-Log curve of static NBTI degradation time evolution. A fast on-the-fly method is developed to overcome this problem. (3) An ultra-fast (100ns) transient pulse Vth measurement method is developed to avoid the recovery of fast NBTI component during measurement, and is compared to the fast on-the-fly measurement results with excellent agreement. (4) Our experiments show that there are two NBTI components, fast and slow. The fast component measured by ultra-fast pulsed method is mainly due to trapping de-trapping of oxide charge. All experimental results can be well explained in this scheme with very good quantitative agreement between the modeling and the experimental data.

I. Two different traps (fast and slow) in HfO2 gate dielectric are identified. For the slow traps, the negative U (-U) property of trap is proposed and confirmed by the first principle calculation. Each trap can trap two electrons or two holes and lower the trap energy due to a large lattice relaxation. The observed experimental result of reduction in slow component of bias temperature instability (BTI) degradation with an increase in stress frequency can be simulated with excellent agreement, based on the concept of - U. A fast BTI component is also observed. The fast dynamic BTI degradation is increased with an increase in stress frequency. It is due to the existence of fast traps and can be simulated by the conventional trapping/de-trapping equations. The fast trap is a standard conventional trap. II. Mixing Ta and La into HfO2 to form HfTaO and HfLaO gate dielectric have been studied systematically. Comparing to the HfO2 gate dielectric, the HfTaO and HfLaO have the advantages of much higher crystallization temperature, much lower charge trapping as well as the BTI degradation, and increased channel mobility. In addition, variation of La concentration in HfLaO/TaN or HfLaO/HfN gate stack can effectively tune the metal work function continuously from mid gap to 4eV. Possible physical explanation for these interesting properties are discussed.

This paper will review some recent results in the study of the DX center in GaAs and AlGaAs using capacitance transient techniques under hydrostatic and uniaxial stress. These measurements have established the DX center as the deep state of substitutional donors in GaAs or AlGaAs which is lowered into the band gap by alloying or pressure.When compared with the predictions of various models of the DX center, the stress results are shown to be consistent with the DX centers having a two electrons negatively charged ground state (negative U).Models of the DX center as effective mass state of donor associated with the L conduction band valleys are found to be incon-sistent with stress experiments.

In this work we report the selective etching characteristics of GaAs grown by molecular beam epitaxy over AlAs etch-stop layer in four etching solutions. We show that these solutions, which are commonly used for selective etching of GaAs grown at the conventional temperature of 600° C (HT GaAs) are also effective for low-temperature GaAs grown at 230° C with annealing at 600° C (a-LT GaAs) and low-temperature-grown GaAs without annealing (LT GaAs). In these solutions, the etching rates of LT GaAs and a-LT GaAs are lower than that of HT GaAs and hence the selectivities of LT GaAs and a-LT GaAs over AlAs are lower than that of HT GaAs over AlAs. The succinic acid/ H2O2solution with pH=4.2 was found to be the best selective etchant. Furthermore, we observed, for the first time, that the AlAs etch-stop layer tended to fail at the periphery of the etched windows, resulting in void formation if the etching was excessive. It took a longer time for this to happen in the succinic acid/ H2O2solution than in other solutions investigated.