Effects of vitamin A on the activity of glutathione system enzymes of liver detoxication after administration of nitroso-compound precursors to rats

The activity of glutathione system enzymes exposed to nitroso-compound (NC) precursors in small doses for 12 months and preliminary injection of vitamin A have been studied. The histo- and biochemical examinations have revealed a pronounced increase in the enzyme activity exposed of NC precursors and a slight increase when injecting preliminary vitamin A.     

Adsorption of sodium atoms on the (111) germanium surface

Within the framework of the Anderson-Newns model and taking into account the dipole-dipole repulsion and the exchange interaction, the work-function variation caused by the adsorption of sodium atoms is calculated for the (111) germanium surface. The obtained results agree well with the experimental data. However, the suggested model fails to describe adequately the Na/Si(111) adsorption system.     

Electromigration Effect on Vacancy Islands Nucleation on Si(100) Surface during Sublimation

Semiconductors - By means of in situ ultrahigh vacuum reflection electron microscopy, the nucleation of vacancy islands on wide terraces of the Si(100) surface is investigated. The temperature...     

Effect of modifiers of microsomal enzymes on the enzymatic denitrosation of dialkyl-N-nitrosamines

The antioxidant butyl-hydroxytoluene has been shown to increase denitrosation of some dialkyl-N-nitrosamines by the liver microsomes of different lines of rats and to protect against diethyl-N-nitrosamine toxicity. 3-Methylcholanthrene, while decreasing denitrosation of diethyl-N-nitrosamine, increased its toxic effect. This data suggested that enzymatic denitrosation is an effective pathway for the inactivation of dialkyl-N-nitrosamines.     

MgO在含铅PTCR陶瓷中的作用

研究了ＭｇＯ加入到含铅ＰＴＣＲ陶瓷中的作用。用碱土金属Ｍｇ２＋对（Ｂａ，Ｐｂ）ＴｉＯ３掺杂，在１２４０～１３００℃空气中烧结，获得工艺性能良好，烧结温度较低，电性能优良的ＰＴＣＲ陶瓷材料。试验结果表明：ＭｇＯ的加入降低了含铅ＰＴＣＲ陶瓷的烧结温度，抑制了ＰｂＯ的挥发。     

Effect of the Crystallographic Orientation of GaSb Films on Their Structural Properties during MBE Heteroepitaxy on Vicinal Si(001) Substrates

Semiconductors - GaSb films are grown by molecular-beam epitaxy using AlSb/As/Si transition layers on vicinal Si(001) substrates miscuted by 6° in (111) plane direction. The effect of GaSb...     

A tutorial on the Digital Audio-Visual Council (DAVIC)standardisation activity

International compatibility for the distribution of video and multimedia content through communication networks is something which has thus far not been achieved. New digital systems provide an opportunity for global compatibility between audio and video transmission and full multimedia communications incorporating text, data, audio, still and moving video in an interactive environment. It is with this commercial opportunity in mind that the Digital Audio-Visual Council (DAVIC) has been created and its first standards, DAVIC1.0 and 1.1, have been released. In Europe the European Commission is actively supporting the development of DAVIC through its Advanced Communications Technologies and Services (ACTS) initiative but DAVIC has widespread international support     

(Ba,Co,Nb)掺杂SnO2压敏材料电学非线性的研究

通过对样品的伏安特性，晶界势垒的测量和分析，研究了BaCO3对新型(Co，Nb)掺杂SnO2压敏材料微观结构和电学性质的影响。晶界势垒高度测量表明，SnO2晶粒尺寸的迅速减小是压敏电压急剧增高的原因。对Ba含量增加引起SnO2晶粒减小的根源进行了解释。掺杂x(BaCO3)=0．4％的SnO2压敏电阻击穿电压为最小(140V／mm)；掺杂x(BaCO3)-0．8％的SnO2压敏电阻具有最高非线性系数(α=19．6)，最高的势垒电压(ψB=1．28eV)。     

Effect of the annealing temperature on erbium ion electroluminescence in Si:(Er,O) diodes with (111) substrate orientation

The influence of the temperature of secondary annealing, stimulating the formation of optically and electrically active centers, on the erbium ion electroluminescence (EL) at λ≈1.54 μm in (111) Si:(Er,O) diodes has been studied. The diodes were fabricated by the implantation of 2.0 and 1.6 MeV erbium ions at doses of 3×10¹⁴ cm⁻² and oxygen ions (0.28 and 0.22 MeV, 3×10¹⁵ cm⁻²). At room temperature, the EL intensity in the breakdown mode grows with the annealing temperature increasing from 700 to 950°C. At annealing temperatures of 975–1100°C, no erbium EL is observed in the breakdown mode owing to the formation of microplasmas. The intensity of the injection EL at 80 K decreases with the annealing temperature increasing from 700 to 1100°C. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 35, No. 10, 2001, pp. 1224–1227. Original Russian Text Copyright ? 2001 by Sobolev, Emel’yanov, Nikolaev.     

InSb（111）、（211）及（110）晶面腐蚀极性研究

极性是InSb晶体结构的一种属性,文中研究了这种极性对InSb晶片湿法腐蚀的影响,并对这种极性产生的原因进行了分析.结果表明,对于工艺中常用的CP4腐蚀液,(111)及(211)晶面腐蚀时表现出极性,(111)A面平均腐蚀速率为2.2 μm/s,(111)B面的平均腐蚀速率为3.6 μm/s;(211)A面的平均腐蚀速率为3 μm/s,(211)B面的平均腐蚀速率为4.8 μm/s;而(110)晶面在腐蚀时未表现出极性效应,只存在一种腐蚀速率为4 μm/s.     

Reduced indium incorporation during the MBE growth of In(Al,Ga)As

A reduction in indium incorporation during the MBE growth of In(Al,Ga)As at moderate temperatures has been observed by RHEED oscillations and confirmed by X-ray diffractometry. The cause is believed to be surface segregation which can result in an under-estimate of the indium flux calculated from InAs RHEED oscillations, and the growth under non-optimum conditions of In-deficient In(Al,Ga)As with poor morphology.<>     

Piezophototronic Effect Enhanced Photoresponse of the Flexible Cu(In,Ga)Se2 (CIGS) Heterojunction Photodetectors

The Cu(In,Ga)Se₂ (CIGS) heterojunction, as a mature and high efficiency thin‐film solar cell, is rarely studied as a photodetector, especially in flexible substrates. In this paper, the structure of an ITO/ZnO/CdS/CIGS/Mo heterojunction is grown on the polyimide (PI) substrate to form a flexible CIGS heterojunction photodetector. The photodetector can work in a very wide band ranging from 350 to 1200 nm with responsivity up to 1.18 A W^?1 (808 nm), detectivity up to 6.56 × 10¹⁰ Jones (cmHz^1/2 W^?1), and response time of 70 (/88) ms, respectively. Moreover, the piezophototronic effect is first used to investigate performance modulation of this device by effectively controlling the separation and transport of carriers at the interface of CdS/ZnO. Interestingly, by externally applying a 0.763% tensile strain, the photoresponsivity and detectivity of the photodetector exhibit a decrease from 1.18 to 0.88 A W^?1, and from 6.56 × 10¹⁰ to 4.81 × 10¹⁰ Jones, respectively, while under a –0.749% externally static compressive strain, the photoresponsivity could be enhanced by ≈75.4% with a maximum of 2.07 A W^?1, and the detectivity is improved by ≈66.1% with its peak value up to 10.9 × 10¹⁰ Jones. Meanwhile, the response time can be modulated from 99(/116) to 41.3(/42.6) ms. This work suggests that the CIGS heterojunction has great potential in novel applications for piezophototronic sensors and also gives a hint to modulate the performance of other multilayer heterostructures via the piezotronic effect.     

Effect of Carrier-Doping on the Thermoelectric Properties of Narrow-Bandgap (Fe,Ru)Ga3 Intermetallic Compounds

We have focused on the binary narrow-bandgap intermetallic compounds FeGa₃ and RuGa₃ as thermoelectric materials. Their crystal structure is FeGa₃-type (tetragonal, P4₂/mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4–5–W–m^?1–K^?1. Both compounds have narrow-bandgaps of approximately 0.3–eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350–<–|S _373K|–<–550–μV–K^?1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa₃ and RuGa₃ as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa₃ (electron-doping) and by substitution of Zn for Ga in RuGa₃ (hole-doping), mainly as a result of optimization of the electronic part, S ² σ.     

Effect of As overpressure on Si-doped (111)A, (211)A and (311)A GaAs grown by molecular beam epitaxy

Si-doped (111)A, (211)A and (311)A GaAs samples grown by molecular beam epitaxy (MBE) at different As over-pressures have been studied. Hall effect measurements have revealed that the doping changes from p- to n-type when the As pressure is increased. The transition As pressure is lower for the (211)A than for the (311)A surfaces. Photo-luminescence measurements have shown that, when the As pressure is increased, arsenic vacancy defects are changed into pairs of Ga vacancy and Ga antisite defects. These results are explained by considering the orientation dependence of the surface bonding and the kinetics of the MBE growth process.     

A muscle fatigue index based on the relationship between precedingbackground activity, and myotatic reflex response (MRR)

A new index of muscular fatigue was developed using the myotatic reflex response (MRR). The MRR of masseter muscles is evoked by periodical mechanical chin tapping during clenching. The MRR waveform is composed of somewhat synchronized action potentials of muscle fibers. We estimate the change of the MRR waveform due to fatigue using the instantaneous frequency pattern (IFP) with the Hilbert transform. As a result, the features of IFP were different from the monotonic changes that have been observed by the conventional fatigue indices. That is, a plateau IFP was observed ahead of considerable fatigue, whereas the IFP showed a monopeak pattern during other phase of an exercise. Also, the relationship between the preceding background mean power frequency and the instantaneous frequency around the first part of the MRR waveform was nonlinear during the whole process of fatigue. These features may allow us to estimate the degree of fatigue at each time instant. Although the details have not yet been solved, by using the computer simulations one of them seemed to be the alteration of the dominant frequency components. The dominant frequency components may be related to the active muscle fiber types.     

The capillary of the organum vasculosum laminae terminalis (OVLT) in rabbits is more permeable to horseradish peroxidase (HRP) than that in rats

The distribution of the tracer, horseradish peroxidase (HRP), in the organum vasculosum laminae terminalis (OVLT) of rabbits and rats was examined by electron microscopy. In rabbits, the HRP-diaminobenzidine reaction products were heavily distributed in the OVLT and surrounding brain tissues 10 and 60 min after the injection of HRP (50 mg kg(-1), i.v.), and were retained in the parenchymal tissues at 24 h post-injection. The majority was found in numerous large phagosomes of macrophages located in the perivascular spaces of the vascular beds and in ependymal cells (tanycytes) in the parenchyma. A large amount of reaction product was also localized in the intercellular clefts of the parenchyma. HRP-incorporation was seen in both nerve cells and ependymal cells in the OVLT at 10 min post-injection, but only in nerve cells in the preoptic area at 60 min post-injection. In rats, however, a small amount of the reaction products was observed in the OVLT 10 min after the injection of HRP (50 and 70 mg kg(-1), i.v.), and the levels were markedly reduced at 60 min post-injection. No HRP-incorporation by nerve cells was seen. From these findings, we concluded that the capillary of the OVLT of the rabbit is more permeable to HRP than that of the rat.     

PbO-B2O3-CuV2O6掺杂对(Pb,Ca,La)(Fe,Nb)O3陶瓷微波介电性能的影响

研究了PbO3-CuV2O6(PBC)玻璃对(Pb,Ca,La)(Fe,Nb)O3(PCLFN)陶瓷微波介电性能的影响.当纯PCLFN陶瓷在1150℃烧结,介电常数εr=103,品质因数与频率之积Qf=5640 GHz,频率温度系数τf=7.1×10-6/℃.PBC玻璃添加剂能降低PCLFN陶瓷的烧结温度到1 050℃左右,同时能保持良好的介电性能.随着PBC玻璃添加量的质量分数从1.0%增加2.0%,陶瓷的Qf值减小.掺杂ω(PBC)=1%玻璃、在1 050℃烧结的陶瓷样品,能获得良好的微波介电性能为Qf=5 392 GHz,τf=8.18×10-6/℃,εr=101.     

Effect of Temperature on the Morphology of Planar GaAs Nanowires (Simulation)

Semiconductors - The self-catalyzed growth of planar GaAs nanowires is analyzed using the lattice kinetic Monte Carlo model. Vapor–liquid–solid nanowire growth on (111)A and (111)B...     

Effect of Electromagnetic Interference (EMI) on the DC Shift,Harmonic and Intermodulation Performance of Diode-Connected NMOSFET

In this paper a new approximation is presented for the nonlinear relationship between the gate-to-source voltage and the current of a diode-connected NMOSFET. Using this expression closed-form expressions are obtained for the DC and the amplitudes of the fundamental, second- and third-harmonic and intermodulation components of the gate-to-source voltage resulting from exciting the diode-connected NMOSFET by a DC biasing current plus a superimposed multisinusoidal EMI. Comparison between calculated and simulated results is included.