Characteristics Of Low Temperature Research Articles

Production and characteristics of low temperature and low density plasma using a magnetic filter

Plasma with low temperature (~ 0.3 eV) and low density (~ 105 cm−3) electrons is produced in a DP device using magnetic filter. The magnetic filter allows the passage of low energy electrons and ions from the source where plasma is produced. Plasma parameters for different discharge current and discharge voltage at different partial pressure of Argon are measured with the help of plane Langmuir probes of 20 mm and 6 mm diameter in target and source section respectively. The magnetic filter is found suitable for production of low temperature plasma with TeS/TeT ~ 10 and low density with NeS/NeT ~ 105 (where TeS and TeT are electron temperature and NeS and NeT are electron density in source and target section respectively). Such type of low temperature and low density plasma can be useful in fields like producing negative ion rich plasma; study of lower ionospheric plasma and study of sheath mechanism, beam plasma interaction, waves and instabilities.

Over-expression of a cold-induced plasma membrane protein gene ( MpRCI) from plantain enhances low temperature-resistance in transgenic tobacco

The plasma membrane is the most direct target of low temperature injury in plants. We have cloned a cold-induced gene ( MpRCI) from plantain ( Musa paradisiaca L.; ABB Group). Expression of an MpRCI::GFP fusion protein in onion epidermal cells showed localization of the protein product in the plasma membrane. The expression profile of MpRCI was analyzed by RT-PCR and the results indicated that MpRCI is induced by low temperatures in leaves and leafstalk, but not in the shoot meristematic or roots. We also cloned a 1.2 kb fragment upstream of MpRCI, predicted to contain several elements related to abiotic stresses, and demonstrated that the sequence has characteristics of low temperature- and ABA-induced promoter activity. Furthermore, the results of the phenotypic espial and ion leakage assays, using transgenic tobacco containing the gene, indicated that over-expression of the cold-induced plasma membrane protein gene MpRCI enhanced low temperature-resistance in the these plants. These results suggest that MpRCI is involved in maintaining the stability of the plasma membrane at low temperatures.

A comprehensive analytical on-current model for polycrystalline silicon thin film transistors based on effective channel mobility

A comprehensive analytical ON-state drain current model for poly-Si thin film transistors (TFTs) is developed to accurately fit both transfer and output characteristics of either low or high temperature processed poly-Si TFTs in both n- and p-types, with the same unified analytical form. The model is physical explicitly based and mathematically accurate, with no artificial factors introduced. To accomplish this, (1) the most appropriate model precisely describing the gate voltage dependent mobility degradation effect in poly-Si TFTs is determined from three previously employed models; (2) grain boundary barrier controlled carrier conduction model is adequately incorporated; and (3) a mathematically accurate analytical form for drain current is derived based on gradual channel approximation by introducing a new fitting parameter to describe the effective average channel mobility. Channel length modulation effect is introduced in modeling output characteristic. Applicability and accuracy of the model are demonstrated by fitting both n- and p-types poly-Si TFTs fabricated from very different processes.

Characterization of the low temperature dopant activation behavior at NiSi/silicon interface formed by implant into silicide method

Process temperature and thermal budget control are very important for high- k dielectric device manufacturing. This work focuses on the characteristics of low temperature activated nickel silicide/silicon (M/S) interface formed by implant into silicide (IIS) method. By combining SIMS, C– V, I– V, and AFM measurements in this work, it provides a clear picture that the high dopant activation ratio can be achieved at low temperature (below 600 °C) by IIS method. From SIMS and C– V measurements, high dopant activation behavior is exhibited, and from I– V measurement, the ohmic contact behavior at the M/S junction is showed. AFM inspection displays that under 2nd RTA 700 °C 30 s no agglomeration occurs. These results suggest that IIS method has the potential to integrate with high- k dielectric due to its low process temperature. It gives an alternate for future device integration.

Theoretical evaluation of trans-critical CO 2 systems in supermarket refrigeration. Part II: System modifications and comparisons of different solutions

The performance of CO 2 refrigeration systems strongly depends on the operating conditions. The specific characteristics of low critical temperature and high operating pressure limit its applications and imply the implementation of different control strategies. This study compares the performance of different CO 2 system solutions for supermarket refrigeration with R404A system. Some possible modifications and improvements on the CO 2 system have been investigated. The COP of the investigated CO 2 system solution can be improved by about 3–7% along the ambient temperature range of 10–40 °C. The annual energy consumption calculations in three different climates; cold, moderate and hot, show that the centralized trans-critical CO 2 system is good solution for cold climates whereas the NH 3–CO 2 cascade system has the lowest energy consumption in hot climates. Both systems proved to be good alternatives to R404A DX system for supermarket refrigeration.

Characteristics of low temperature and low oxygen diesel combustion with ultra-high exhaust gas recirculation

Ultra-low NOx and smokeless operation at higher loads up to half of the rated torque is attempted with large rates of cold exhaust gas recirculation (EGR). NOx decreases below 6 ppm (0.05 g/kW h) and soot significantly increases when first decreasing the oxygen concentration to 16 per cent with cold EGR. However, after peaking at 12–14 per cent oxygen, soot then decreases sharply to essentially zero at 9–10 per cent oxygen while maintaining ultra-low NOx, regardless of fuel injection quantity and injection pressure. However, at higher loads, with the oxygen concentration below 9–10 per cent, the air-fuel ratio has to be over-rich to exceed half of the rated torque, and thermal efficiency, CO, and THC deteriorate significantly. As the EGR rate increases, exhaust gas emissions and thermal efficiency vary with the intake oxygen content rather than with the excess air ratio. Longer ignition delays due to either advancing or retarding the injection timing reduced the smoke emissions, but advancing the injection timing has the advantages of maintaining the thermal efficiency and preventing misfiring. A reduction in the compression ratio is effective to reduce the in-cylinder temperature and increase the ignition delay as well as to expand the smokeless combustion range in terms of EGR and i.m.e.p. (indicated mean effective pressure).

Preparation and performance analysis of barium dispenser cathodes

The intercorrelation of aluminate properties, such as structure, component and metal Os film coating with electron emission capability and longevity of Ba dispenser cathodes, has been investigated. It is shown that reactants react completely and the percentage of tribarium aluminates is larger in the normal environment, and that at 1723 K the pulse of cathode impregnated in the above aluminates is larger. Aluminates sintered under the normal environment constitute the multiphase formation, but aluminates sintered under the special environment with Ar gas injection compose the single-phase formation by means of X-ray diffraction (XRD). Both the surface and the fracture surface of cathode are full of aluminates evenly distributed by using Sirion 200 superhigh resolving power field emission scanning electron microscope (SEM). The emission current density of cathode-impregnated aluminates sintered in the special environment with Ar gas injection is larger than that in the common environment by the analysis of diode experiments. The emission capability of Os-coated cathode prepared by laser ablation deposition (LAD), which has good characteristics of low temperature is higher, than that without metal film coating cathodes.

Magnetic catalyst residues and their influence on the field electron emission characteristics of low temperature grown carbon nanotubes

We report the electron paramagnetic resonance characteristics of catalytic residues for in situ grown carbon nanotube field electron emitter and present direct evidence that field electron emission in carbon nanotube sheets grown on various catalytic nanodots/SiO2-coated Si substrate with low-pressure chemical vapor deposition is influenced by the magnetism of catalytic metals and thus the electrical properties of the nanotubes. The nanotubes with weak trace of ferromagnetism, which originated from the catalysts, show lower turn-on emission field and higher electron emission current than those with distinct ferromagnetic properties. A strong relationship between the ferromagnetism of nanocrystalline catalysts and field electron emission characteristics of nanotubes can be utilized for the development of an efficient carbon nanotube based-field electron emitter.

백야도 연안의 동계 해양환경 특성에 따른 식물플랑크톤의 종조성과 군집 분석

This study was to clarify the variations in a marine ecosystem through examining the species composition of phytoplankton in the coastal water of Baegyado Island during winter. Water temperature, salinity, SS, NH-N, NO-N, NO-N and SiO-Si were significantly different and in inverse proportion to the chlorophyll a and species number according to stations and water depth. The total number of species was 88, composed of 94% Bacillariophyceae, 3.4% Chrysophyceae, 2.2% Dinophyceae and 1.1% Euglenophyceae. The dominant species were Rhizosolenia setigera, Skeletonema costatum and Stephanopyxis palmeriana. The maximum of standing crops was 5,450cells·ml^(-1), while the minimum was 1,700cells·ml^(-1). The coastal water was influenced with two water bodies which had characteristics of low water temperature - low salinity and high water temperature - high salinity.ᔌ䄀؀㔱㤮㔻Ԁ䭃䑎䷗੿6〰㬅K䍄乍숗ጊЀ㌱〻Ԁ䭃䑎䶭᜕౾3㄰⸵㬅K䍄乍

Characteristics of Low Body Temperature in Secondary School Boys

The purpose of this study was to verify the relationship of the occurrence of low body temperature at rising time and intraday body temperature changes, rising time, going-to-bed time, exercise hours, heart rate at rising time, and intrinsic motivation for attending school at rising time. The subjects, 452 healthy junior and senior high school male students, were divided into two groups, namely, Average group (AG) with an axillary temperature above 36.0 and below 37.0 at rising time and Low group (LG) with an axillary temperature below 36.0. The temperature was taken on a weekday without physical exercise classes in school in June 1999 and in the same month in 2001. The level of intraday body temperature of LG was lower than that of AG. The body temperature of AG reached its peak around noon, but that of LG peaked around 4 o'clock in the afternoon. The body temperature at going-to-bed time of LG did not get lower to the level at rising time. The heart rate of LG (66.6±9.0 beat · min-1) was significantly lower than that of AG (70.9±10.7 beat · min-1). The intrinsic motivation for attending school of LG (3.0±1.1 points) was significantly lower than that of AG (3.6±1.2 points). Those with the above motivation in LG (36.6%) were significantly smaller in number than those in AG (54.4%). The students with an axillary temperature below 36.0 at rising time were found to have characteristically lower level of intraday body temperature, showing the highest at around 4 o'clock in the afternoon. Also their going-to-bed time temperature did not go lower to the level of rising time. Furthermore, their heart rate was low at rising time and they were low in the intrinsic motivation for attending school at rising time.

The characteristics of low temperature co-fired multilayer chip LC filters

Ferrite co-fired with dielectric materials and pure silver below 900/spl deg/C is the key issue in the production process for multilayer chip LC filters. The addition of glass to TiO/sub 2/ reduced the sintering temperature, improved the characteristics of the dielectric constant and decreased the dissipation factor below 0.1% at 1 MHz. The glass induced the silver to diffuse quickly into the interface of the ferrite and the doped TiO/sub 2/ dielectric ceramic as well as the surface. Glass will deteriorate the dielectric properties and worse the attenuation and the noise filtering ability in the processed, LC filter, ferrite and TiO/sub 2/ dielectric ceramic without glass doping can be processed for good performance multilayer chip LC filters.

The Impacts of Back-End High Temperature Thermal Treatments on the Characteristics and Gate Oxide Reliability of Thin Film Transistor in Ultra Large Scale Integrated Circuit Process

The impacts of the two major high temperature treatments on the characteristics of thin film transistors (TFT's) in the back-end process of ultra large scale integrated circuit (ULSI) technology have been investigated. TFT's without any high temperature treatment show poor characteristics. High temperature furnace annealing and rapid thermal annealing (RTA) which are performed for boron phosphorous tetra ethyl ortho silicate (BPTEOS) planarization can improve the characteristics of low temperature recrystallized TFT. Then, the technologies used for contact annealing result significant difference on the characteristics of TFT's. High temperature furnace contact annealing can still greatly improve the characteristics of TFT's. However, after furnace annealing for BPTEOS planarization, RTA contact annealing deteriorates the characteristics of TFT. High temperature furnace annealing for BPTEOS planarization improves the charge to breakdown (Q bd) value of the gate oxide of TFT and so does the furnace contact annealing. However, RTA contact annealing performed after the furnace planarization flow deteriorates that of the gate oxide.

Characteristics of low temperature serrated flow in CuBe alloy

In the homogenized Cu2Be alloy discontinuous flow has been investigated at 4.2 K. The behaviour of serrated yielding is dependent on the strain rate and sample diameter. The strain rate sensitivity of the yield stress is slightly negative whereas the stress for the onset of serrated flow increases with increasing strain rate. The dependence of this stress as well as the yield stress on the sample diameter indicates that thermal instability plays an important role. In der homogenisierten Legierung Cu2Be wurde diskontinuierliches Fließen bei 4.2 K untersucht. Das Verhalten des diskontinuierlichen Fließen ist von der Verformungsgeschwindigkeit abhängig. Die Geschwindigkeitsempfindlichkeit der kritischen Fließspannung ist schwach negativ. Die Einsatz-spannung für diskontinuierliches Fließen steigt mit der Verformungsgeschwindigkeit. Beide charak-teristische Spannungen sind vom Probendurchmesser abhängig, was darauf schlißen läßt, daß eine thermische Instabilität eine wichtige Rolle spielt.

Hot carrier degradation in low temperature processed polycrystalline silicon thin film transistors

The effects of hot carrier degradation on the characteristics of low temperature processed polycrystalline silicon thin film transistors (poly-Si TFTS) have been studied for devices formed by several different technologies. In all cases the degradation is found to result from the formation of interface acceptor states in the upper half of the band gap, and to donor states near to mid-gap. The worst case conditions for degradation are identified, and device reliability lifetime is deduced. No additional effects are found to arise from AC stressing, and degradation in NMOS shift registers is found to be consistent with the results of simple stress tests.

Electrical Characterization of Low Temperature GaAs Layers, and Observation of the Extremely Large Carrier Concentrations in Undoped Material

ABSTRACTWe present here the results of a study on the effect of substrate temperature, Ts, on the electrical and physical characteristics of low temperature (LT) molecular beam epitaxy GaAs layers. Hall measurements have been performed on the asgrown samples and on samples annealed at 610 °C and 850 °C. Si implantation into these layers has also been investigated.

Entrainment of Bimodal Circatidal Rhythms in the Shore Crab Carcinus maenas

Individuals of the shore crab Carcinus maenas were exposed to artificial cycles, applied in tidal antiphase, of pairs of the three major environmental variables that entrain circatidal rhythmicity in this species: salinity, temperature, and hydrostatic pressure. During entrainment, the observed locomotor activity patterns were dominated by exogenous responses to high pressure, low temperature, or low salinity. In subsequent constant conditions, many of the crabs showed bimodal circatidal rhythms, with peaks phased to the times of expected high-tide characteristics of high pressure, low temperature, or high salinity. Similar bimodal rhythms were induced by exposing freshly captured crabs, with free-running circatidal rhythms, to tidal antiphase cycles of each of the three environmental variables applied individually. The hypothesis that circatidal rhythmicity in this species is controlled by at least two separate circatidal oscillators, with differential sensitivities to specific cyclical environmental variables, is discussed.

Effects of combined temperature and salinity on the entrainment of endogenous rhythms in the shore crabcarcinus maenas

Shore crabs (Carcinus maenas) were exposed in the laboratory to simultaneous, artificial tidal cycles of temperature and salinity. Cycles applied with high salinity coincident with low temperature, the normal pattern of such variables on the shore in summer, induced exogenous tidal rhythmicity at times of low salinity and re‐set endogenous circatidal rhythmicity. In subsequent constant conditions the endogenous circatidal rhythm persisted with maximum activity at “expected”; times of high salinity/low temperature. When the two variables were applied in tidal antiphase the dominant cycle of activity during treatment is an apparent tidal cycle driven by episodes of low salinity. In constant conditions after such treatment, however, a semi‐circatidal (6.2 h) pattern of activity was exhibited, suggesting that summer high tide characteristics of high salinity and low temperature applied in tidal antiphase entrain separate circatidal components of the crabs’ physiological clocks.

Principles and Characteristics of Low Temperature Passivated (LTP) Transistors

Principles and Characteristics of Low Temperature Passivated (LTP) Transistors