TC-336氧氮分析仪测定钢中氧化物分量的初步探讨

惰气熔融热导红外法已广泛用于金属及其它固体材料中总氧量的测定。但随着科技工作的发展，研究人员既要了解测试材料氧总含量，又想了解测试材料中不同氧化物的分量。本文拟对TC-336氧氮分析仪测定钢中氧化物分量进行初步探讨。

ICP—AES法测定夹杂中稳定氧化物分量

夹杂样品经过电解，定量保留稳定氧杂物，经灼烧恒重，称取氧化物总量。总量经熔剂熔融，用稀酸加热浸出，用去离子水定容，导入ICP系统测定。

Effect of exhaust gas recirculation and intake pre-heating on performance and emission characteristics of dual fuel engines at part loads

Achieving simultaneous reduction of NOx,CO and unburned hydrocarbon(UHC) emissions without compromising engine performance at part loads is the current focus of dual fuel engine research.The present work focuses on an experimental investigation conducted on a dual fuel(diesel-natural gas) engine to examine the simultaneous effect of inlet air pre-heating and exhaust gas recirculation(EGR) ratio on performance and emission characteristics at part loads.The use of EGR at high levels seems to be unable to improve the engine performance at part loads.However,it is shown that EGR combined with pre-heating of inlet air can slightly increase thermal efficiency,resulting in reduced levels of both unburned hydrocarbon and NOx emissions.CO and UHC emissions are reduced by 24% and 31%,respectively,The NOx emissions decrease by 21% because of the lower combustion temperature due to the much inert gas brought by EGR and decreased oxygen concentration in the cylinder.

A Dual Wavelength Differential First Derivative Spectrophotometric Method for Identification and Determination of Carbon Monoxide Generated During the Microsomal Metabolism of Xenobiotics in vitro

A dual wavelength differential first derivative spectrophotometric method has been developed to standardize the concentration of a saturated aqueous solution of carbon monoxide (CO) as the standard and to identify and to determine CO formed during the microsomal metabolism of xenobiotics in vitro. The method can significantly eliminate the background interference in the assay media and increase the quantitative accuracy and the sensitivity. There is a good linear relationship between CO concentration in the range of 2～10 μmol·L 1 CO and the distance D between the first derivative peak at 415 nm amd valley at 426 nm with r=0.9999(n=5),the regression equation being C (mmol·L 1 )=17.6D 0.4, the detection limit lower than 0.1 μmol·L 1 CO. The average recoveries of CO from the assay system and the sample were 102.1%, RSD=2.9% (n=7) and 79.7%, RSD=6.8% (n=12),respectively. The RSD of within day was 4.4%(n=18),and the RSD of day to day was 6.1%(n=16). By this method, four trihaloanilines and one trihalobenzene were tested, the results showed that only 2,4,5 trifluoroaniline could be converted to CO by the incubation with rat hepatic microsomes, NADPH and oxygen, the ability of phenobarbital or dexamethasone to induce rat hepatic microsomes to catalyze CO formation was 3 or 8 times higher than that of the control.

Energetic analysis of gasification of biomass by partial oxidation in supercritical water

Partial oxidation gasification in supercritical water could produce fuel gases(such as H2, CO and CH4) and significantly reduce the energy consumption. In this work, an energetic model was developed to analyze the partial oxidative gasification of biomass(glucose and lignin) in supercritical water and the related key factors on which gasification under autothermal condition depended upon. The results indicated that the oxidant equivalent ratio(ER) should be over 0.3 as the concern about energy balance but less than 0.6 as the concern about fuel gas production. Feedstocks such as glucose and lignin also had different energy recovery efficiency. For materials which can be efficiently gasified, the partial oxidation might be a way for energy based on the combustion of fuel gases. Aromatic materials such as lignin and coal are more potential since partial oxidation could produce similar amount of fuel gases as direct gasification and offer additional energy. Energy recovered pays a key role to achieve an autothermal process. Keeping heat exchanger efficiency above 80% and heat transfer coefficient below15 k J·s-1is necessary to maintain the autothermal status. The results also indicated that the biomass loading should be above 15% but under 20% for an autothermal gasification, since the increase of biomass loading could improve the energy supplied but decrease the efficiency of gasification and gaseous yields. In general,some specific conditions exist among different materials.

Thermo economic evaluation of oxy fuel combustion cycle in Kazeroon power plant considering enhanced oil recovery revenues

Oxy fuel combustion and conventional cycle(currently working cycle) in Kazeroon plant are modeled using commercial thermodynamic modeling software. Economic evaluation of the two models regarding the resources of transport and injection of carbon dioxide into oil fields at Gachsaran for enhanced oil recovery in the various oil price indices is conducted and indices net present value(NPV) and internal rate of return on investment(IRR) are calculated. The results of the two models reveal that gross efficiency of the oxy fuel cycle is more than reference cycle(62% compared to 49.03%), but the net efficiency is less(41.85% compared to 47.92%) because of the high-energy consumption of the components, particularly air separation unit(ASU) in the oxy fuel cycle. In this model, pure carbon dioxide with pressure of 20×105 Pa and purity of 96.84% was captured. NOX emissions also decrease by 4289.7 tons per year due to separation of nitrogen in ASU. In this model, none of the components of oxy fuel cycle is a major engineering challenge. With increasing oil price, economic justification of oxy fuel combustion model increases. With the price of oil at $ 80 per barrel in mind and $ 31 per ton fines for emissions of carbon dioxide in the atmosphere, IRR is the same for both models.

Antiaging activity of low molecular weight peptide from Paphia undulate

Low molecular weight peptide (LMWP) was prepared from clam Paphia undulate and its antiaging effect on D-galactose-induced acute aging in rats, aged Kunming mice, ultraviolet-exposed rats, and thermally injured rats was investigated. P. undulate flesh was homogenized and digested using papain under optimal conditions, then subjected to Sephadex G-25 chromatography to isolate the LMWP. Administration of LMWP significantly reversed D-galactose-induced oxidative stress by increasing the activities of glutathione peroxidase (GPx) and catalase (CAT), and by decreasing the level of malondialdehyde (MDA). This process was accompanied by increased collagen synthesis. The LMWP prevented photoaging and promoted dermis recovery and remission of elastic fiber hyperplasia. Furthermore, treatment with the LMWP helped to regenerate elastic fibers and the collagen network, increased superoxide dismutase (SOD) in the serum and significantly decreased MDA. Thermal scald-induced inflammation and edema were also relieved by the LWMP, while wound healing in skin was promoted. These results suggest that the LMWP from P. undulate could serve as a new antiaging substance in cosmetics.

Purification and characterization of novel antioxidant peptides of different molecular weights from mackerel Pneumatophorus japonicus protein hydrolysate

Mackerel （Pneumatophorus japonicus） proteins were hydrolyzed by five proteases： trypsin, papain, neutrase, acid protease, and flavourzyme. The hydrolysate treated by neutrase exhibited the highest antioxidant activity. Response surface methodology （RSM） was employed to optimize the hydrolysis conditions in an effort to obtain a mackerel protein hydrolysate （MPH） with the highest DPPH radical scavenging activity. The MPH was fractioned using a series of ultrafiltration membranes and five fractions, namely, MPH-I （〉10 kDa）, MPH-II （10-2.5 kDa）, MPH-III （1-2.5 kDa）, MPH-IV （0.4-1 kDa）, and MPH-V （below 0.4 kDa）, were obtained. DPPH radical scavenging activity, reducing power, hydroxyl radical scavenging activity, and the lipid peroxidation inhibition capability of these fractions were evaluated. The fractions in molecular weights 〈2.5 kDa （MPH-III, MPH-IV, and MPH-V）, which occupied 93.4% of the total fractions, showed the strongest antioxidant activity; and the antioxidant activities of the three fractions are similar to each other. Using SP Sephadex C-25 and Sephadex G-25 columns, eight fractions were obtained from the MPH （〈2.5 kDa）. The isolated peptide I （1 664 kDa） displayed the highest DPPH radical scavenging activity. Therefore, MPH is a potential source of antioxidant peptides.

The Response of Chickpea to Irrigation with Treated Waste Water

In a three-year study, the response of four cultivars of chickpea, Bulgarit, WIR-32, Jordan and ICC 11293 to irrigation with TW （treated wastewater） and FW （freshwater）, using surface and subsurface drip irrigation was investigated. Wastewater generated from Al-Quds university campus included black, grey and storm water was treated by small scale pilot plant. The wastewater pilot plant consists of tailored made secondary biological activated sludge process with daily capacity of 50 m3. The influent and effluent chemical and biological quality parameters were routinely monitored and analyzed. The data reveal that the average values for BOD, COD and EC for the effluent are 50 ppm, 136 ppm and 1.4 mS/cm over 2 years period. The results of chickpea growth parameters and the chemical and biological analysis of the seeds and leaves indicate that the cultivars Bulgarit and ICC 11293 can be irrigated with TW without any loss in yield and quality. Factor analysis reasonably favored Bulgarit Cultivar irrigated with treated effluent over other cultivars. WIR-32 and Jordan cultivars showed significant reduction in their growth parameters when irrigated with TW as compared with FW. Surface and subsurface drip irrigation gave similar results in most cases. Soil analysis in this study showed no significant difference between irrigation with TW and FW.

Study on the Molecular Weight Composition and Antioxidant Activity of Peanut Bioactive Peptides

[ Objective] To prepare peanut bioactive peptides and analyze their molecular weight composition and antioxidant activity. [ Method ] The dialysis bag of 8.0, 3.5 and 1.0 kD were used to classify the hydrolyzate derived from alcalase and flavourzyme, peanut bioactive poptides of differ-ent molecular weight were obtained and then their scavenging capacity of free radicals was measured. The molecular weight composition was stud-ied by Tricine-SDS-PAGE.[Result] The content of peptides 〈 1.0 kD were 76.21% and 83.42% in the total hydrolyzate from alcalase and fla-vourzyme respectively. All hydrolyzate with different molecular grades showed free radical scavenging capacity, which was increased with the reduc- tion of molecular mass. The peptides 〈 1.0 kD exhibited higher radical scavenging capacity of （87.41 ±0.66） % （alcalase） and （67.88 ±0.48）% （ flavourzyme）, respectively. [ Conclusion] Peanut bioactive peptides had strong effect of antioxidant capacity, especially that 〈 1.0 kD, which had great prospect.

A New Method for Comparing Hospital and Municipal Wastewater

The objective of this study is to investigate the differences in organic compounds that are present in hospital and municipal wastewater samples. Two samples with the same COD （chemical oxygen demand） values were chosen for this study. The results have shown that both samples consist of the same compounds with low molecular weights and high polarities in high concentrations. The hospital wastewater consisted of more compounds arithmetically. Differences were found in the organic compound with low molecular weight and low polarities. Pharmaceutical compounds such as caffeine, acetanilide and phenacetin were detected only in the hospital wastewater.