锥栗和茅栗淀粉颗粒的特性

采用显微观察、X-射线衍射分析和碘电位滴定法等对锥栗和茅栗淀粉颗粒特性进行了研究.结果表明:锥栗和茅栗淀粉颗粒的形状比较规则,具有明显的偏光十字,大小分别在1.0～18.6μm和1.5～19.1μm之间,颗粒的晶体结构均属于C型;锥栗和茅栗淀粉的糊化温度分别为63.5～74.5℃和64.0～73.5℃,直链淀粉含量分别为22.33%和22.87%;两种淀粉颗粒的溶解度和膨胀度较小,而其膨胀度在75℃时出现迅速增长,属限制型膨胀淀粉.

Variation in litter decomposition-temperature relationships between coniferous and broadleaf forests in Huangshan Mountain, China

A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes （Phenoloxidase, peroxidase, !5-glucosidase and endocellulase） and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.

Effects of slurry pack cementation temperature on microstructure and wear resistance of Ti-Al co-deposited coating on copper plated nickel layer

In order to improve the wear resistance properties of copper substrate, a layer of electroplated nickel was firstly deposited on copper substrate, subsequently these electroplated specimens were treated by slurry pack cementation process with a slurry pack cementation mixture composed of TiO2 as titanizing source, pure Al powder as aluminzing source and also a reducer for titanizing, an activator of NH4Cl and albumen （egg white） as cohesive agent. The Ti-Al coating was fabricated on the surface of electro-deposited nickel layer on copper matrix followed by the slurry pack cementation process. The effects of slurry pack cementation temperature on the microstructures and wear resistance of Ti-Al coating were studied. The results show that the microstructure of the coating changed from NiAl＋Ni3（Ti,Al） to NiAl ＋Ni3（Ti,Al）＋Ni4Ti3 to Ni4Ti3＋NiAl, and to NiAl＋Ni3（Ti,Al）＋NiTi with slurry pack cementation temperature ranging from 800 ℃ to 950 ℃ in 12 h. The friction coefficient of Ti-Al coating decreased and the hardness increased with increasing the slurry pack cementation temperature. The minimum friction coefficient was 1/3 and the minimum hardness was 5 times larger than that of pure copper.

A BEEM Study on Effects of Annealing Temperature on Barrier Height Inhomogeneity of CoSi_2/Si Contact Formed in Co-Ti-Si Systems

Ultra thin epitaxial CoSi 2 films are fabricated by solid state reaction of a deposited bilayer of Co(3nm)/Ti (1nm) on n Si(100) substrates at different temperatures.The local barrier heights of the CoSi 2/Si contacts are determined by using the ballistic electron emission microscopy (BEEM) and its spectroscopy (BEES) at low temperature.For CoSi 2/Si contact annealed at 800℃,the spatial distribution of barrier heights,which have mean barrier height of 599meV and a standard deviation of 21meV,obeys the Gaussian Function.However,for a sample that is annealed at 700℃,the barrier heights of it are more inhomogenous.Its local barrier heights range from 152meV to 870meV,which implies the large inhomogeneity of the CoSi 2 film.

First and Second Laws Analyses of a Closed Latent Heat Thermal Energy Storage System

First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2·6H2O). The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses, respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experimente that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.

Catalytic reduction of NO_x by biomass-derived activated carbon supported metals

In this study,to prepare a series of activated carbon-supported metals for the catalytic reduction of NO_x to N_2 in excess O_2,activated carbons derived from lignocellulosic and herbaceous biomasses were selected as the reducing agents,and alkali and transition metals were used as the catalytic active phases.The effects of the type of biomass,carbonization temperature and catalyst composition on NO_x reduction efficiency were analyzed in a fixed-bed flow reactor.The results showed that two temperature regimes are present for the NO_x-carbon reaction:at temperatures below 250°C,the NO_x adsorption process on the carbon surface was predominant,whereas true NO_x reduction by carbon occurred at temperatures above 250°C,producing N_2,CO_2 and CO.The influence of the carbonization temperature on carbon reactivity depended on the effect of the carbonization temperature on the carbon surface area and the reduction of the metal species on carbon.All studied metals catalyzed both NO_xand O_2reduction by carbon,and potassium could strongly enhance the C-NO_x reaction without substantial carbon consumption by O_2.Moreover,the potassium supported by sawdust-derived activated carbon exhibited higher selectivity and capacity towards NO_x reduction than did its previously reported coal-derived counterparts.These properties were ascribed to the high dispersion of the active potassium species on the carbon surface,as observed through the comparison of X-ray photoelectron spectroscopy and powder X-ray diffraction results for the carbons made from biomass and coal-based precursors.

Effect of temperature on copper corrosion in high-level nuclear waste environment

The effect of temperature on the corrosion behavior of copper in simulated high-level nuclear waste environment wassystematically studied.Electrochemical methods,including electrochemical impendence spectra,Mott–Schottky technology,cyclicpolarization,and potentiostatic polarization,were employed to characterize the corrosion behavior of copper at different temperatures.Stereoscopic microscopy and scanning electron microscopy were used to examine the surface morphology,and X-ray photoelectronspectroscopy analysis was used to identify the composition of the passive film.The experimental results show that corrosionresistance of the passive film does not blindly decrease with the increase of temperature but increases at60°C owing to a compactouter layer;there is a potential for pitting corrosion,which decreases as the temperature increases.The main product of copper in ananaerobic aqueous sulfide solution is Cu2S but the content of CuS increases at higher temperatures.The whole passivation rangeshows p-type semiconductor characteristics and the magnitude of the acceptor density is1023cm-3,which increases with increasingtemperature.

The relationship between the microstructures and catalytic behaviors of iron–oxygen precursors during direct coal liquefaction

A series of both unsupported and coal‐supported iron–oxygen compounds with gradual changes in microstructure were synthesized by a precipitation‐oxidation process at 20 to 70°C.The relationship between the microstructures and catalytic activities of these precursors during direct coal liquefaction was studied.The results show that the microstructure could be controlled through adjusting the synthesis temperature during the precipitation‐oxidation procedure,and that compounds synthesized at lower temperatures exhibit higher catalytic activity.As a result of their higher proportions ofγ‐FeOOH orα‐FeOOH crystalline phases,the unsupported iron–oxygen compounds synthesized at 20–30°C,which also had high specific surface areas and moisture levels,generate oil yields 4.5%–4.6%higher than those obtained with precursors synthesized at 70°C.It was also determined that higher oil yields were obtained when the catalytically‐active phase formed by the precursors during liquefaction(pyrrhotite,Fe1-xS)had smaller crystallites.Feed coal added as a carrier was found to efficiently disperse the active precursors,which in turn significantly improved the catalytic activity during coal liquefaction.

SOFC temperature evaluation based on an adaptive fuzzy controller

The operating temperature of a solid oxide fuel cell (SOFC) stack is a very important parameter to be controlled, which impacts the performance of the SOFC due to thermal cycling. In this paper, an adaptive fuzzy control method based on an affine nonlinear temperature model is developed to control the temperature of the SOFC within a specified range. Fuzzy logic systems are used to approximate nonlinear functions in the SOFC system and an adaptive technique is employed to construct the controller. Compared with the traditional fuzzy and proportion-integral-derivative (PID) control, the simulation results show that the designed adaptive fuzzy control method performed much better. So it is feasible to build an adaptive fuzzy controller for temperature control of the SOFC.

Derivatives of 3（5）,4-Dinitropyrazole as Potential Energetic Plasticisers

The development of a pseudo-one pot synthesis of 3（5）,4-dinitropyrazole enabled us to use it as a starting material for energetic plasticisers. Its acidic proton allowed simple derivatisation on one of the ring nitrogens. The thermal characteristics of two derivatives were evaluated. For instance, the N-allyl compound was a liquid with very low glass transition temperature, whereas the N-propargyl compound was a sticky solid at ambient temperature. The two compounds were both thermally stable according to STANAG 4582.

A New Quenching Process and Tower to Improve the Recovery of Acrylonitrile

Quenching process and design of the quenching tower in acrylonitrile production in China were studied in order to decrease the polymerization loss of acrylonitrile in the quenching tower. Based on the research of acrylonitrile polymerization in the quenching tower, a new quenching process was proposed to avoid the disadvantages of the original process. Two kinds of internals were installed to improve the performance of the quenching tower. Through a series of air-flow and real-flow model experiments, the new quenching process and new design were showed to be successful in enhancing the mass and heat transfer in the vapor-liquid system and decreasing the loss of acrylonitrile.Industrial application showed satisfactory results of decrease of the acrylonitrile loss in the quenching tower by about 4.5% and increase of the acrylonitrile recovery of the whole plant by more than 4%.

Effects of co-precipitation temperature on structure and properties of La and Y doped cerium zirconium mixed oxides

Due to the oxygen storage and release properties,cerium zirconium mixed oxides are recognized as the key material in automotive three-way catalysts.To reveal the effects of co-precipitation temperature on structure,physical and chemical properties of multi-doped cerium zirconium mixed oxides,a series of La and Y doped cerium zirconium mixed oxides(CZLYs)were synthesized via a co-precipitation method,and the physical and chemical properties of CZLYs were systemically characterized by XRD,N_(2) adsorption−desorption,TEM,XPS,oxygen storage capacity(OSC)and hydrogen temperature programmed reduction(H_(2)-TPR).The results show that co-precipitation temperature is an important parameter to influence the crystal size,oxygen storage capacity and thermal stability of CZLYs.When the co-precipitation temperature was 60℃,the best redox properties and thermal stability of CZLYs were obtained.After thermal treatment at 1100℃for 10 h,the specific surface area and oxygen storage capacity of the corresponding aged sample were 15.42 m^(2)/g and 497.7μmol/g,respectively.In addition,a mechanism was proposed to reveal the effects of co-precipitation temperature on the structure and properties of CZLYs.

Influence of Zeotropic Mixtures' Temperature Gliding on the Performance of Heat Transfer in Condenser or Evaporator

Many zeotropic refrigerant mixtures are proposed as alternatives to some chlorofluorocar-bons (CFCs) and hydrochlorofluorocarbons ( HCFCs). An advantage of zeotropic mixtures is the possibility of reduction in entropy generation by matching the temperature glidings of refrigerant and heat-transfer fluid in both condenser and evaporator. Zeotropic mixtures are compared with pure re-frigerants to evaluate their exergetic losses. On the other hand, the special phenomena which result from temperature gliding are proved by experiments. A simple equation is obtained, to evaluate dif-ferent zeotropic mixtures' exergetic losses. The maximum flow rate of heat-transfer fluids is found in order that refrigerants phase change can be completed. Lastly, some examples of zeotropic mix-tures ( R407C, R405A and R414B) are given, and their exergetic losses and maximum flow rate of heat-transfer fluids in condenser are forecasted.

Study on Property of Polypropylene Catalyst with New Internal Donor

A P-substituted sulfonyl-containing compound was synthesized in the lab. The structure of the compound was demonstrated by 1H and 31P NMR. The propylene polymerization catalysts were prepared by incorporating an internal donor, and the content of Ti, H and C in the catalysts was also checked by elemental analysis. The effect of dosage of the donor, the Al/Ti ratio and the polymerization temperature on the catalyst activity were studied, the results suggested that the dosage of donor, the Al/Ti ratio and the polymerization temperature could affect not only the activity of catalyst but also the isotacticity index of the polymer. A catalyst with high activity was selected, and the polypropylene formed in the presence of this catalyst had high isotacticity index.

Crystallization Behavior and Properties of B-Doped ZnO Thin Films Prepared by Sol-Gel Method with Different Pyrolysis Temperatures

Boron-doped zinc oxide transparent （BZO） films were prepared by sol-gel method. The effect of pyrolysis temperature on the crystallization behavior and properties was systematically investigated. XRD patterns revealed that the BZO films had wurtzite structure with a preferential growth orientation along the c-axis. With the increase of pyrolysis temperature, the particle size and surface roughness of the BZO films increased, suggesting that pyrolysis temperature is the critical factor for determining the crystallization behavior of the BZO films. Moreover, the carrier concentration and the carrier mobility increased with increasing the pyrolysis temperature, and the mean transmittance for every film is over 90% in the visible range.

An Investigation to Assess Storage Stability of Pomelo Seed Oil Biodiesel

Biodiesel is a biomass-based renewable and clean fuel. It can be used directly in existing diesel engines without any modification. In spite of having so many advantages, it has an issue regarding long-term storage stability. Biodiesel oxidizes when it comes in proximity of light, temperature, humidity, metals etc. The oxidation causes precipitation and sedimentation in the fuel. Such biodiesel is unfit to use in engines. Hence, this study aims to assess the storage stability of pomelo seed oil （Citrus maxima） biodiesel over a period of five months upon storage both in open and closed condition. Storage stability of biodiesel is determined in terms of acid value, peroxide value and viscosity at regular interval of time. It is observed that there is a strong relationship between oxidation and outside factors such as light, temperature fluctuations and humidity level. Upon exposure to these factors, oxidation in biodiesel accelerated greatly.

Mechanical properties and friction-wear characteristics of VN/Ag multilayer coatings with heterogeneous and transition interfaces

The heterogeneous multilayer interface of VN/Ag coatings and transition multilayer interface of VN/Ag coatings were prepared on Inconel 781 and Si(100),and the microstructures,mechanical and tribological properties were investigated from 25 to 700℃.The results showed that the surface roughness and average grain size of VN/Ag coatings with transition multilayer interface are obviously larger than those of VN/Ag coatings with heterogeneous multilayer interface.The coatings with transition multilayer interface have higher adhesion force and hardness than the coatings with heterogeneous multilayer interface,and both coatings can effectively restrict the initiation and propagation of microcracks.Both coatings have excellent self-adaptive lubricating properties with a decrease of friction coefficient as the temperature increases,but their wear rates reveal a drastic increase.The phase composition of the worn area of both coatings was investigated,which indicates that a smooth Ag,Magnéli phase(V2O5)and bimetallic oxides(Ag3VO4 and AgVO3)can be responsible to the excellent lubricity of both coatings.To sum up,the coatings with transition multilayer interface have excellent adaptive lubricating properties and can properly control the diffusion rate and release rate of the lubricating phase,indicating that they have great potential in solving the problem of friction and wear of mechanical parts.

Ethene／norbornene copolymerization by[Me2Si（3—^tertBuCp）（N^tertBu）]TiCl2／MAO—catalyst

?Ethene/norbornene copolymerization by the catalyst system [Me_2Si( 3- tertBuCp)(N tertBu)]TiCl_2/MAO was investigated in detail at 30 ℃, 60℃, and 90℃. A mass flow controller was used in this work to obtain kine tic data and investigate tempera ture's effects on activity, norbornene incorporation, copolymerization parameter , microstructure, glass transition temperature, and molar masses were described. H igh copolymerization values r_E and high alternation are determined. The n umber of isotactic alternating sequences is much higher than that of the syndiot actic alter nating sequences.

A study on simultaneous removal of NO and SO2 by using sodium persulfate aqueous scrubbing

Nitric oxide （NO） removal and sulfur dioxide （SO2） removal by sodium persulfate （Na2S2O8） were studied in a Bubble Column Reactor. The proposed reaction pathways of NO and SO2 removal are discussed. The effects of temperatures （35-90℃）, Na25208 （0.05-0.5 mol·L-1）, FeSO4 （0.5-5.0 m mol·L-1） and H2O2 （0.25 mol·L-1） on NO and SO2 removal were investigated. The results indicated that increased persulfate concentration led to increase in NO removal at various temperatures. SO2 was almost completely removed in the temperature range of 55-85 ℃. Fe2 ＋ accelerated persulfate activation and enhanced NO removal efficiency. At 0.2 mol· L- 1 Na2S2O8 and 0.5-1.0 mmol· L-1Fe2 ＋, NO removal of 93.5%-99% was obtained at 75-90 ℃, SO2 removal was higher than 99% at all temperatures. The addition of 0.25 mol. L i H202 into 0.2 mol·L-1· Na2S2O8 solution promoted NO removal efficiency apparently until utterly decomposition of H2O2, the SO2 removal was as high as 98.4% separately at 35 ℃ and 80 ℃.

Preparation and properties of pitch carbon based supercapacitor

Using the mesophase pitch as precursor, KOH and CO2 as activated agents, the activated carbon electrode material was fabricated by physical-chemical combined activated technique for supercapacitor. The influence of activated process on the pore structure of activated carbon was analyzed and 14 F supercapacitor with working voltage of 2.5 V was prepared. The charge and discharge behaviors, the properties of cyclic voltammetry, specific capacitance, equivalent serials resistance （ESR）, cycle properties, and temperature properties of prepared supercapacitor were examined. The cyclic voltammetry curve results indicate that the carbon based supercapacitor using the self-made activated carbon as electrode materials shows the desired capacitance properties. In 1 mol/L Et4NBF4/AN electrolyte, the capacitance and ESR of the supercapacitor are 14.7 F and 60 mΩ respectively, The specific capacitance of activated carbon electrode materials is 99.6 F/g; its energy density can reach 2,96 W.h/kg under the large current discharge condition, There is no obvious capacitance decay that can be observed after 5000 cycles, The leakage current is below 0,2 mA after keeping the voltage at 2.5 V for l h, Meanwhile, the supercapacitor shows desired temperature property; it can be operated normally in the temperature ranging from -40 ℃to 70 ℃,