铈锆固溶物载Pd催化剂的构造特征及其活性

以共沉淀法和滤纸作为模板剂的模板法制备铈锆固溶物 (Ce/Zr=1 )负载Pd催化剂 ,用XRD对其进行晶相分析 ,两种方法均形成立方萤石结构 .TPR实验揭示了滤纸模板法制备的铈锆固溶物高温老化催化剂更易被还原 .催化剂表面Pd的分散度和活性评价实验表明 ,催化剂表面贵金属的分散度在一定程度上决定催化剂的活性 ,载体物性影响Pd的分散度 ,滤纸模板法制备的铈锆固溶物负载Pd催化剂有较高的Pd分散度 ,表现出比共沉淀法制备的铈锆固溶物负载Pd催化剂好的三效活性 .

关于固溶体在无机非金属材料中应用的研究

改革开放以来，我国的科学技术飞速发展，新材料、新技术不断发现和研究，而在这些新材料中，固溶物在一些非金属材料中的应用非常广泛，并且发展的前途很好。固溶物在工程陶瓷等非技术材料的制备过程中作为催化剂，能大大提高非金属材料的性能和产量。在一些非金属制备中通过一些固溶体的掺入，会在根本上改变无机材料的性质，生产出性能好的新型材料，因此在以后的非金属材料制备中的应用越来越重要。本文主要对固溶物的特点、性质及在非金属材料中的应用进行一些研究和分析。

基于高光谱成像的苹果多品质参数同时检测

利用高光谱空间散射曲线的3个洛伦兹拟合参数对苹果的品质(硬度、可溶性固溶物含量)进行同时检测。采用偏最小二乘,逐步多元线性回归和BP神经网络3种方法,对归一化处理和未归一化处理的3个洛伦兹参数组合分别建立苹果品质的预测模型。结果表明:采用偏最小二乘法对未归一化处理参数的组合建立硬度的预测模型其预测结果最好,校正组相关系数Rc=0.93,校正标准差SEC=0.56,验证组相关系数Rv=0.84,验证标准差SEV=0.94。采用偏最小二乘法对归一化处理参数的组合建立可溶性固形物的预测模型其预测结果最好,Rc=0.95,SEC=0.29,Rv=0.83,SEV=0.63。研究结果表明:利用高光谱空间散射曲线的多拟合参数组合可以同时检测苹果的多品质参数。

Catalytic reduction of SO_2 by CO over CeO_2-TiO_2 mixed oxides

The structure and catalytic desulfurization characteristics of CeO2-TiO2 mixed oxides were investigated by means ofX-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and catalytic activity tests. According to the results, a CeO2-TiO2solid solution is formed when the mole ratio of cerium to titanium n（Ce）：n（Ti） is 5：5 or greater, and the most suitable n（Ce）：n（Ti） isdetermined as 7：3, over which the conversion rate of SO2 and the yield of sulfur at 500℃ reach 93% and 99%, respectively.According to the activity testing curve, Ce0.7Ti0.3O2 （n（Ce）：n（Ti）=7：3） without any pretreatment can be gradually activated by reagentgas after about 10 min, and reaches a steady activation status 60 min later. The XPS results of Ce0.7Ti0.3O2 after different time ofSO2＋CO reaction show that CeO2 is the active component that offers the redox couple Ce4＋/Ce3＋ and the labile oxygen vacancies, andTiO2 only functions as a catalyst structure stabilizer during the catalytic reaction process. After 48 h of catalytic reaction at 500℃,Ce0.7Ti0.3O2 still maintains a stable structure without being vulcanized, demonstrating its good anti-sulfur poisoning performance.

密度计在计量中的应用

叙述了密度计首次在工厂计量过程中的应用情况．列出了有关的运算公式，并对仪器的软件改进作了简单阐述．

Isothermal section of Mg-rich corner in Mg-Zn-Al ternary system at 335 °C

The phase equilibria and compositions at the Mg-rich corner of the Mg?Zn?Al ternary system at 335 °C were systemically investigated through the equilibrated alloy method by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy dispersive spectroscopy of X-ray (EDS). It is experimentally testified that theα-Mg solid solution is not in equilibrium with the Mg32(Al, Zn)49 (τ) ternary intermetallic compound orq quasicrystalline phase, but only in equilibrium with one ternary intermetallic compound Al5Mg11Zn4 (φ). The whole composition range of theφ phase was also obtained at 335 °C, i.e., 52.5%?56.4% Mg, 13.6%?24.0% Al, 19.6%?33.9% Zn (mole fraction). The solubility of Al in the MgZn phase is remarkably more than that in the Mg7Zn3 phase, and the maximum is about 8.6% Al. Aluminum and zinc are simultaneously soluble in theα-Mg solid solution.

Phase equilibria of Mg-rich corner in Mg Zn Al ternary system at 300 °C

The phase equilibria and compositions in Mg-rich comer at 300℃ were determined in the Mg-Zn-A1 ternary system through the equilibrated alloy method by using X-ray diffraction （XRD） and scanning electron microscopy （SEM） assisted with energy dispersive spectroscopy of X-ray （EDS）. The results show that there exist three three-phase regions consisted of a-Mg＋Mg17A112（7）＋A15Mg11Zn4（φ）, a-Mg＋Mga2（Al, Zn）49（r）＋A15MgllZn4（φ） and a-Mg＋MgZn＋Mg32（A1, Zn）49（r）, respectively. The intermetallic compounds in equilibrium with a-Mg phase all have large composition ranges, not appear to be linear. At the same time, both zinc and aluminum are soluble in the a-Mg solid solution, with which the compounds are in equilibrium.

Effects of Peracetic Acid(PAA) Combined with Calcium Treatments on Storage Quality of Loquat Fruit

[Objective] The paper was to evaluate effects of peracetic acid （PAA） combined with calcium treatments on storage quality of Ioquat fruits, so as to pro- vide practical techniques to solve the problems of postharvest rot and quality deteri- oration for Ioquat fruits. [Method] With Ioquat fruits of Qingzhong variety as materi- als, 0.2%, 0.4% and 0.8% PAA combined with 0.8% CaCI2 was used to soak Ioquat fruits for 4 min, 0.8% CaCl2 and water treatments were set as two controls; the fruits were dried and packaged by 0.02 mm PE bags, then stored under non-chilling low temperature of （7±1） ℃. The indicators related to storage quality of Ioquat fruits were randomly tested once every 3 d, and their variation situations were analyzed. [Result] Compared with two control treatments and 0.2% PAA, 0.8% PAA combined with calcium treatments, the treatment of 0.4% PAA combined with 0.8% CaCl2 could significantly inhibit rot index, weight loss rate, firmness and cell membrane permeability of Ioquat fruits during storage period, which could also effectively delay the reduction of titratable acid, vitamin C, soluble solid content and juice yield, and maintain respiration intensity of fruits at a low level; the appearance and flavor qual- ity of fruits were good after stored for 25 d. [Conclusion] 0.4% PAA combined with 0.8% CaCl2 treatment is an efficient, safe and economical practice technology in an- ti-corrosion and quality preservation for postharvest Ioquat fruits .

产糖率和废蜜产率的简明计算

本文介绍糖厂产糖率和废蜜产率计算与实际生产偏差的原因,并通过实例,论述如何更准确计算产糖率及废蜜产率,使之切合生产实际,使生产报表数据更加准确,达到指导生产的作用。

Effect of solution treatment on corrosion characteristics of biodegradable Mg-6Zn alloy

A binary Mg-6Zn biodegradable alloy was solution treated to evaluate the effects of resulting microstructure changes on the alloy＇s degradation rate and mechanisms in-vitro. The treatment was conducted at 350 °C for 6-48 h. Optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction were used to analyze the as-cast and treated samples. Immersion and electrochemical tests were performed in simulated body fluid at 37 °C to assess the samples corrosion resistance. To confirm the results of the corrosion tests, p H measurement was carried out. It is found that over 24 h solution treatment dissolves intermetallic phases in matrix and produces an almost single phase microstructure. Decreasing the intermetallic phases results in lower cathode/anode region ratios and lowers corrosion rates. The results of the electrochemical and mass loss tests reveal that extended solution treatment improves the corrosion resistance of the alloy. The results also show that solution at 350 °C for 24 h enhances the corrosion resistance of the as-cast alloy more than 60%. In addition, decreasing intermetallic phases in the microstructure accompanied a lower p H rise reduced corrosion rate. Solution treatment is suggested as a corrosion improving process for the application of Mg-Zn alloys as biodegradable implant materials.

ZnxCd1–xS quantum dot with enhanced photocatalytic H2-production performance

H2 is an important energy carrier for replacing fossil fuel in the future due to its high energy density and environmental friendliness.As a sustainable H2-generation method,photocatalytic H2 production by water splitting has attracted much interest.Here,oil-soluble ZnxCd1-xS quantum dot(ZCS QD)with a uniform particle size distribution were prepared by a hot-injection method.However,no photocatalytic H2-production activity was observed for the oil-soluble ZCS QD due to its hydrophobicity.Thus,the oil-soluble ZCS QD was converted into a water-soluble ZCS QD by a ligand-exchange method.The water-soluble ZCS QD exhibited excellent photocatalytic H2-production performance in the presence of glycerin and Ni^2+,with an apparent quantum efficiency of 15.9%under irradiation of 420 nm light.Further,the photocatalytic H2-generation activity of the ZCS QD was~10.7 times higher than that of the ZnxCd1-xS relative samples prepared by the conventional co-precipitation method.This work will inspire the design and fabrication of other semiconductor QD photocatalysts because QD exhibits excellent separation efficiency for photogenerated electron-hole pairs due to its small crystallite size.

Influence of La precursors on structure and properties of CeO_2-ZrO_2-Al_2O_3 composite oxides

Three La-doped CeO2-ZrO2-Al2O3(CZA)composite oxide samples,namely,CZA-I,CZA-II and CZA-III,were prepared following a co-precipitation method in the presence of La2O3,La(NO3)3-6H2O and H[La(EDTA)]-16H2O precursors,respectively.When the precursor samples are sintered at 1000°C,the as-prepared composite oxides mainly exhibit the CeO2-ZrO2 cubic fluorite phase,while theγ-Al2O3 andδ-Al2O3 phases appear when the precursor samples are subjected to sintering at 1100 and 1200°C.CZA-III exhibits improved redox properties after high-temperature treatment compared with CZA-I and CZA-II.CZA-III presents the largest surface area of 97.46 m2/g among the three CZAs when the CZA-III precursor sample is sintered at 1000°C.Furthermore,the corresponding oxygen storage capacity(OSC)is the largest with value of 400.27μmol/g when CZA-III precursor sample is sintered at 1000°C.Additionally,CZA-III exhibits the best thermal stability and the highest reduction temperature.However,by increasing the sintering temperature to 1200°C,there is a dramatic decline in the properties of surface area and OSC.And a decrease for CZA-III in surface area by 58.94%and a decrease of the OSC value by 74.56%are observed.

Quality and Nutrition of Pummelo as Influenced by Potassium

This study aimed to determine the influence of different rates of K （potassium） and K foliar application on the quality and plant nutrition condition of 13-year old ＇Magallanes＇ pummelo trees [Citrus maxima （Burm. ex Rumph.） Merr.]. The experiment was conducted at SODACO （South Davao Corporation） farm, Davao City, Philippines from March to October 2010. Five treatments with increasing K levels were applied per tree： control, no K, 150 g K basal, 225 g K basal and 225 g K basal ＋ foliar application. Application of 225 g K rates positively influenced fruit quality of pummelo. Fruit pulp diameter and juice weight increased while peel thickness decreased. The 225 g K rates also increased juice pH, TA （titrable acidity） and TSS （total soluble solids） per tree. The yield of total phenol, flavonoid, vitamin C and oil per tree increased with 225 g K application. Results of the soil analysis before and after the conduct of the study showed an evidence of fertilizer absorption by the trees. It was also observed that foliar fertilization reduced soil acidity. This indicates the important role of K in improving the nutrient utilization and quality of ＇Magallanes＇ pummelo.

Effect of the Biostimulant Foliar Addition of Marine Algae on cv, O＇Neal Blueberries Production

In the Retiro, ＂El Lucero＂ county, Maule, VII Region of Chile, an application of a marine algae extract known as Ascophilliurn nodosum, whose commercial name is Ekologik~, was evaluated by applying it to the whole foliage in order to evaluate the impact on total weight, average weight, equatorial diameter and soluble solids in cv. O＇Neal blueberries harvested in a three-year old orchard having a plantation density of 3,333 plants hal. The marine algae extract was applied in three phenologic phases： full bloom, fruit set and fruit color break. Four treatments were conducted： To, application of pure water （without the product）; T1, a 280 mL ha1 dose per application; T2, a 140 mL ha^-1 dose, equivalent to 50% of the treatment dose T1; and T3, a 420 mL ha^-1 dose, equivalent to a 50% extra than the treatment dose T1. The experimental design comprised sutb-sampling blocks with three repetitions of three uniform and healthy plants per treatment. Regarding the total and average fruit weight, they did not show significant statistical differences, but an increase in the average weight of fruits treated with the aforementioned product was observed. For parameters such as equatorial diameter, caliper and soluble solids of harvested fruit, the product caused a statistically significant increase. T3 was found to be the best treatment with a 15% weight, increasing taste, sugar amount, size and weight of the harvested fruits.

Effect of Vacuum Cooling on Shelf Life of Organic Chayote Shoot （Sechium edule Sm.）

The effect of vacuum cooling on shelf life of organic chayote was investigated. Vacuum cooling processes of organic chayote shoot packed in perforated polyethylene package using different vacuum pressure reserving operation modes were experimented. The holding final pressures for vacuum-cooled organic cilantro packed in holed polyethylene bags were set at two different levels, namely at 10 and 11 millibar. The pressures were experimented with 3 levels of reserving time of 3, 4 and 5 minutes. The weight loss percentage of chayote shoot during precooling to the temperature of 8 ~ 1 ~C using reserving pressure of 10 milibars for 3, 4, and 5 minutes were 0.5, 0.7, and 0.9, respectively. For the weight loss percentage during precooling using reserving pressure of 11 milibars for 3, 4, and 5 minutes were 0.4, 0.5, and 0.5, respectively. The optimum parameter for vacuum cooling process of organic chayote shoot at the initial temperature of 19-23 ℃to 8 ±1 ℃was the reserving pressure of 11 mbar with reserving time of 5 minutes. The precooled organic chayote shoot was then stored at 8 ℃ for quality analysis. The results showed that vacuum cooling had no effect on the change of color, chlorophyll a, b and total chlorophyll. However, precooled organic chayote shoots showed better appearance than non-precooled vegetables. Vacuum cooling can reduce weight loss percentage. The amount of total soluble solids in organic chayote shoots increased with storage time. Precooled organic chayote shoot had longer shelf life of 8 days compared to normal storage life of 5 days.

Experimental Research on Flue Gas Desulfurization by Superfine Titanium Dioxied

The mechanism of all present adopted desulfurization technologies is chemical reaction. A new kind of desulfurization medium - TiO 2 particle having large fraction void and specific surface area which is made from TiO 2 with superfine size sintered at low temperature and processed with surface activation is tested and investigated. The mechanism of desulfurization is mainly physical adsorption instead of traditional chemical reaction. Four samples of such TiO 2 particles were characterized by advanced instruments and tested for adsorption dynamics at the temperature range of 90?℃ to 240?℃ in a fixed bed. The results show that its adsorption ability for SO 2in flue gas is dependent strongly on three factors: quality of TiO 2particles, adsorption temperature and SO 2 concentration in flue gas. Titanium dioxide has well desulfurization character and pretty good prospect in engineering application. Sintered at temperature range from 440?℃ to 540?℃, it has the best adsorption ability. In practical use the best adsorption temperature is around 120?℃.

Enhanced properties of solid solution (CeZr)O_2 modified with metal oxides for catalytic oxidation of low-concentration methane

The solid solution （CeZr）02 catalyst was synthesized, and it was modified with metal oxides by incipient impreg- nation. Morphology and structure were characterized by X-ray diffraction, transmission electron microscope, ni- trogen ad/desorption and H2-temperature program reduction techniques. The catalytic properties of methane oxidation were also investigated. The results showed that solid solution possessed a mesoporous structure and exhibited excellent catalytic performance. The activity of solid solution was improved effectively by nickel dop- ing, and the optimal loading is 15 wt%. The stability of （CeZr）02 and modified （CeZr）02 indicated that the struc- ture of pristine solid solution played a key role in promoting molecules diffusion and spatial confining oxide particle sintering.

Effects of High CO_2 Pretreatment on the Quality of Fresh-Cut Potatoes

Effects of short-term high CO_2 pretreatment on quality of fresh-cut potatoes were studied. Potatoes were treated under 90% CO_2 for 18 h, peeled, cut, dipped in 1% ascorbic acid or distilled water for 3 min, packed in polyethylene bags and stored for 12 d at 4 ℃. Non-treated potatoes were used as the control. High CO2 pretreatments ensured maintenance of a high level of CO_2 in headspace of packages containing fresh-cut potatoes. Both the growth of total aerobic bacteria in initial stages of post-cut storage and browning index of the cut surface were lower in high CO_2 treated cut potato. Anti-browning effect of high CO_2 pretreatment was decreased when applied in combination with ascorbic acid. Soluble solids, pH, titratable acidity and flesh firmness of fresh-cut potatoes were not affected by high CO_2 treatment. Therefore, high CO_2 treatment before slicing could be effective method to maintain quality of flesh-cut potatoes.

Eutectic effect during mesophase formation in co-carbonization of ethylene tar pitch and polystyrene

Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.