双氧水浓品装置1、2段蒸发器结垢原因分析

针对浓品双氧水装置1、2段蒸发器结垢情况。从操作、原料液生产及设备腐蚀方面进行分析,确定其原因之所在。

双氧水浓品装置单耗偏高原因分析及处理

中原大化集团公司双氧水浓品装置于1997年投入生产运行,设计生产能力为5000t/a(质量分数为50％双氧水)。该装置采用减压浓缩蒸馏生产工艺,技术先进,消耗水平低。试生产初期浓品单耗接近设计指标2.1t,随后浓品装置生产单耗逐年上升,严重影响了浓品的生产成本和经济效益。笔者着重分析影响浓品单耗上升的相关原因,并提出改进和维护措施,从而使浓品单耗大幅降低。 1 双氧水浓品生产工艺简介 1.1 浓品生产原理在真空条件下,将低浓度稀双氧水溶液(质量分数为27.5％)在蒸发器中蒸发,其气相为双氧水蒸气和水蒸气,蒸发后需保留少量余液,使溶液中的难挥发性杂质留在剩余液中被除去。

中原大化5kt/a浓品双氧水装置试生产中进行的技术改进

叙述了中原大化集团公司双氧水厂5kt/a浓品装置试生产中进行的技术改进。

芝士香浓品火锅

很多人认识瑞士奶酪火锅，是看了著名音乐人、主持人高晓松的《晓说》。视频中，高晓松讲述了他在瑞士吃奶酪火锅的尴尬经历。话说高老师也是见多识一在美国吃过了改良版的瑞士火锅后，在瑞土一个山里的百年老店吃火锅时，“很有经验地”对服务员提出了加点香肠和蘑菇的要求，结果被店家礼貌地“请”出了，因为“您的行为影响了我们店里的老顾客，是对我们文化的不尊重”。

Dwarfing effects of plant growth regulators on narcissi

The effects of four kinds of plant growth regulators with different concentrations on narcissi were studied in 2001. The results showed that the regulators could inhibit the growths of height and leaves of narcissi. Of the four regulators, the dwarfing effects of paclobatrazol (PP333) and uniconazole (S3307) on narcissi were better than those of chlorocholine (CCC) and dimethyl amino-sussinamic acid (B9). All of the regulators did not have significant effect on the root length. Moreover, the time of flowering was later for the narcissi treated with regulators than that of the control to a certain extent, and the range delayed was from 2 days to 19 days. The correlation analysis results showed that there was a significant correlation between the time of flowering and the concentrations of regulators. The ornament value of narcissi was obviously improved by using the regulators.

Excavation and Screening Utilization of Strong Aroma Tobacco Variety in Chizhou Tobaccogrowing Area

[Objective] This study was aimed to screen out the strong-aroma tobacco variety with good ecological adaptability as the best cultivar in Chizhou. [Method] Based on the ecological conditions that formed the strong aroma style of tobacco leaves in the tobacco-growing area, 6 varieties（K326, NC55, NC71, 0508, Yunyan99, Yan240） were selected and compared through combining the demand characteristics of industrial enterprise to the quality. [Results] The output value of 0508 was the highest and NC71 had a medium output value but with coordinated chemical composition. The system evaluation of this study on the quality and characteristic style further clarified the feature strength and utility value of various tobacco varieties with strong aroma. [Conclusion] NC71 is the best cultivar in Chizhou tobacco-growing area, and it is suggested using NC71 as the demonstrative variety of the next year. The study on the excavation and screening utilization of tobacco varieties with local features is of great significance to the tobacco production industry.

Breeding of a New Thick Red Apple Cultivar Jihong

Jihong is a variation bred by Shijiazhuang Pomology Institute of Hebei Academy of Agriculture and Forestry Sciences. The fruit is big,average fruit weight is234 g,the largest is 500 g. The fruit skin is thick red, easy coloring and the coloring index is 95%. The flesh is crisp, juicy,and moderate sweet-sour taste. The soluble solid content is 16.0%,and it has good qualities,high and stable yield. It is mature at the end of October.

Effects of Controlled Atmospheres with High_O_2 or High_CO_2 Concentrations on Postharvest Physiology and Storability of "Napoleon" Sweet Cherry

Sweet cherries ( Prunus avium L. cv. Napoleon) were stored in controlled atmospheres (CA) of high O(2) (70% O(2) + 0% CO(2)) or high CO(2) (5% O(2) + 10% CO(2)), in modified atmosphere package (MAP, (13% - 18%) O(2) + (2% -4%) CO(2)) and in air (control) at 1 degreesC to investigate the effects of different O(2) and CO(2) concentrations on physiological properties, quality and storability of the fruits during storage. The results indicated that compared with other treatments, CA with high O(2) concentration decreased fruit decay and ethanol content, but increased the accumulation of malondialdehyde (MDA) and stimulated browning. CA with high CO(2) concentration inhibited polyphenol oxidase (PPO) activity, reduced MDA content, maintained vitamin C content and firmness, decreased fruit decay and browning. Soluble solids contents (SSC) were not significantly affected by different atmosphere treatments. 'Napoleon' fruits stored in 5% O(2) + 10% CO(2) for as long as 80 d were of good quality, but only 40, 20 and 30 d stored in MAP, 70% O(2) + 0% CO(2) and air, re-spectively.

Anti-proliferative activity of phlorotannin extracts from brown algae Laminaria japonica Aresch

In this study, we evaluated the anti-proliferative activity of phlorotannins derived from brown algae Laminariajaponica Aresch extracts on the human hepatocellular carcinoma cell （BEL-7402） and on routine leukemic cells （P388） by MTT assay. Cells were incubated with 100 μg/mL of the phlorotannin extract （PE） for 48 h. The inhibitory rate of PE on BEL-7402 and P388 cells was 30.20±1.16% and 43.44±1.86%, respectively, and the half-inhibitory concentration of PE （IC50） on P388 and BEL-7402 cells was 120 μg/mL and 〉200 μg/mL, respectively. Microscopic observation shows that the morphologic features of tumor cells treated with PE and 5-fluorouracil are markedly different from the normal control group. The inhibitory rate of fraction A2 isolated from PE by sephadex LH-20 for BEL-7402 and P388 cells at the sample concentration of 70.42 μg/mL was 61.96±7.02% and 40.47±8.70%, respectively. The apoptosis peak for fraction A2 was the most profound of all fractions used in the flow cytometry assay. The results indicate that the anti-proliferative of this algal extract is associated with the total phlorotannin content.

Heavy Metal Transfer from Soil to Vegetable in Southern Jiangsu Province, China

Vegetable fields in peri-urban areas receive large amounts of extraneous heavy metals because of rapid urbanization and industrialization in China. The concentrations of Cu, Zn, and Pb in 30 soil samples and 32 vegetable samples, collected from 30 different sites in southern Jiangsu Province of China, were measured and their transfer from soil to vegetable was determined. The results showed that the soil samples had wide ranges of pH （4.25-7.85） and electrical conductivity （EC） （0.24-3.42 dS m^-1）. Among the soil samples, there were four soil samples containing higher Cu and two soil samples containing higher Zn concentrations than those specified in the Chinese Soil Environmental Quality Standard II. However, no vegetable sample was found to contain a high level of Cu or Zn. In contrast, one vegetable sample contained 0.243 mg Pb kg^-1 FW, which was above the Chinese Food Hygiene Standard, whereas the corresponding soil Pb concentration was lower than the Chinese Soil Environmental Quality Standard II. The transfer coefficients of Cu of all vegetable samples exceeded the suggested coefficient range, implying that extraneous Cu had high mobility and bioavallability to vegetables. There was no significant correlation between extractable soil heavy metal concentrations with four kinds of extractants and soil pH, EC, heavy metal concentrations in vegetables and soils, except that soil pH correlated well with the extractable soil Cu, Zn, and Pb concentrations with 1.0 mol L-1 NH4NO3. Moreover, diethylenetriamine pentaacetic acid （DTPA） extraction method was a more efficient method of extracting heavy metals from the soils independent of soil pH and EC than other three methods used.

Decomposition and Products of Wheat and Rice Straw from a FACE Experiment Under Flooded Conditions

Winter wheat and rice straw produced under ambient and elevated CO2 in a China rice-wheat rotation free-air CO2 enrichment （FACE） experiment was mixed with a paddy soil at a rate of 10 g kg^-1 （air-dried）, and the mixture was incubated under flooded conditions at 25℃ to examine the differences in decomposition as well as the products of crop residues produced under elevated CO2. Results showed that the C/N ratio and the amount of soluble fraction in the amended rice straw grown under elevated CO2 （FR） were 9.8% and 73.1% greater, and the cellulose and lignin were 16.0% and 9.9% lesser than those of the amended rice straw grown under ambient CO2 （AR）, respectively. Compared with those of the AR treatment, the CO2-C and CH4-C emissions in the FR treatment for 25 d were increased by 7.9% and 25.0%, respectively; a higher ratio of CH4 to CO2 emissions induced by straw in the FR treatment was also observed. In contrast, in the treatments with winter wheat straw, the CO2-C and CH4-C emissions, the ratio of straw-induced CH4 to CO2 emissions, and the straw composition were not significantly affected by elevated CO2, except for an 8.0% decrease in total N and a 9.7% increase in C/N ratio in the wheat straw grown under elevated CO2. Correlation analysis showed that the net CO2-C and CH4-C emission from straw and the ratio of straw-induced CH4 to CO2 emissions were all exponentially related to the amount of soluble fraction in the amended straw （P 〈0.05）. These indicated that under flooded conditions, the turnover and CH4 emission from crop straw incorporated into soil were dependent on the effect of elevated CO2 on straw composition, and varied with crop species. Incorporation of rice straw grown under elevated CO2 would stimulate CH4 emission from flooded rice fields, whereas winter wheat straw grown under elevated CO2 had no effect on CH4 emission.

Selenium in Soils of Moldova

Se （selenium） is an essential trace element for both animals and human beings, although it is considered to be conditionally required for plants. Se occurrence in the environment of Moldova is poorly understood. The objective of this study was to establish Se content and distribution in soils of this country. Se content in samples was detected using fluorometric method. Se concentration in soils ranged from 100 μg·kg^-1 to 668 og-kg-1 dry weight （mean 246 ± 73 μg·kg^-1）. Mainly, Se content in soils was optimal （more than 175 μg·kg^-1）, however, there were soil areas with Se deficiency （lower than 125/μg·kg^-1）. Maximum of Se in soils was observed at the depth of 0.4-0.7 m and then it decreased on going to parent rock. Se content typically increased with increasing of soil clay particles. Se washout from terraces and watershed slopes as well as Se accumulation in relief depressions was shown. High Se concentrations in local surface waters （0.2-6.1 μg·L^-1, mean 1.8 μg·L^-1） indicated the substantial presence of soluble Se forms, which were available to plants. Thus, geochemical conditions of Moldova are favorable for Se bioaccumulation by plants.

看戏吃豆品浓情

鲁迅先生的文章《社戏》，写的是他小时候一段看社戏的往事，表现了灯奄年生活的美好回忆和留恋的心情。对许多人来说，童年是快乐而美好的，鲁迅先生也一样，“看社戏”是一段难忘的体验，

Spectrophotometric Error Due to Uncertainty in Reading the Signal

Based upon the standard deviations for the intercept and the slope of a linear regression line, as well as by differentiating both Beer＇s law and a linear relationship between transmittance and concentration at high transmission, it is proved that the relative spectrophotometric error of a measurement becomes greater as the sample concentration only decreases. Further, it is demonstrated that the present knowledge with regard to the error in absorption spectrophotometry is necessary to be reexamined. The total scale of transmittance can literally be used for measurements, unfolding workable dynamic ranges about two orders of magnitude lower than usually and thus absorption spectrophotometry can efficiently compete with other methods of analysis with respect to detection limits.

New Easy Method for the Monitoring of Hg Concentration in Fish, Using a Nanostructured Gold Electrode

The applicability of a gold nanoparticle-modified glassy carbon sensor （AuNPs-GCS） for the determination of inorganic mercury in fresh and canned tuna fish by square wave anodic stripping voltammetry （SW-ASV） is demonstrated. Mercury content in sample Tuna Fish ISPRA T22 was determined to value the accuracy of the determination. The concentration in this sample is not certified, so, the Hg amount was determined also with atomic absorption spectroscopy （AAS）： the results obtained with ASV were in good agreement and confirmed literature value reported for this sample. Then, real samples of tuna fish were analyzed. The voltammetric analyses were performed using previously optimized conditions （deposition potential 0 V, step potential 0.004 V, frequency 150 Hz and amplitude 0.003 V）. Medium exchange technique permitted to eliminate possible matrix effects. The concentrations in the real samples were found to be in agreement with the common Hg levels reported in literature for commercialized tuna fish in different countries.

Transfer of Heavy Metal Contaminants from Animal Feed to Animal Products

Study was conducted to assess the possible transfer of heavy metals from livestock feeds to animal products. In experiment-l, samples （n = 503） collected from conventional farms in Central Greece were analysed for heavy metal Copper （Cu）, Zinc （Zn）, Cadmium （Cd）, Lead （Pb）, Nickel （Ni） and Chromium （Cr） contents in muscle tissues, livers, kidneys, excremental and basic mixtures in livestock such as cows and sheep. Results showed that transfer of heavy metal contaminants from feed to animal products fluctuated below the permissible risk levels. In experiment 2, samples （n = 440） of feedstuffs used in different feeding regimens and seasons at different livestock farms [sheep （n = 140）, dairy cows （n = 180）, pigs （n = 120）] were collected. Results showed that relatively high concentration of Cu in the excrements of pigs （155 ＋ 9.13） and Zn in the excrements of sheep （144.56 ＋ 5.78） are explained by the use of Cu in the diet of developing piglets and sheep. Ovine showed higher concentration ofNi, Cr, and Pb in their excrements, while, the concentration of heavy metals in forages was under the allowed range to the EU legislation.

Condensation of Water Vapor on Waterproof Breathable Fabrics

Condensation occurs when the local vapor pressure rises above the saturation vapor pressure at the local temperature in theory. A new measuring apparatus were made to obtain temperature and relative humidity simultaneously for the purpose of investigating the mechanism of condensation occurred on the fabrics. The experiment conducted at the standard condition of temperature of 20℃ and relative humidity of 65%. The result obtained from experiment showed that condensation could occur under the situation closed to saturation line as the temperature on fabric may be lower than dew point of water vapor in the measuring box depending on the experiment conducted at an ambient environment temperature of 20℃ The range of fabrics studied showed that PTFE laminated fabrics except nylon gingham PTFE laminated fabric facilitates the loss of water vapor and therefore prevent condensation. It is necessary to develop studies from a wide range of fabrics, especially breathable fabrics and under bad experiment condition in order to develop fabrics, which could eliminate condensation, or transport water vapor through the fabric while remaining waterproof.

The Allelochemicals Effect of Zygophyllum album on Control of Bromus tectorum

The aim of the present study was to investigate the potential allelopathic effects of different concentrations of Zygophyllum album （donor species） aqueous extract （2.5, 5, 7.5 and 10%） on germination percentage, plumule and radicle length ofBromus tectorum （weed） and Triticum aestivum （crop species） under laboratory conditions to have the greatest inhibitory allelopathic effect on the recipient species in mixed culture compared to that pure culture. The germination percentage, plumule and radicle length ofB. tectorum in mixed culture was completely inhibited at the highest concentration of aqueous extracts of the donor species level the exerted weak measures as affected by the highest concentration level of donor in pure culture. This inhibition was markedly in obvious B. tectorum that is more sensitive to tested donor. The domineering effect of aqueous extract of the donor was more prominent on weeds than crop species. The variant response to the allelopathic substance could be related to the species specific growth regulatory effect of allelochemicals and concentration dependent. There is possibility of using these allelochemicals directly or as structural leads for the discovery and development of environment friendly herbicides to control weeds.

Potassium Concentration by Natural ^40K-^40Ar Y Rays Detection in Four Basic Diet Products （Milk, Eggs, Wheat and Corn）

The purpose of this paper is double： first to measure the natural radioactivity in any food by detecting the omnipresent radiation of ^40K, and then to use this date to obtain the concentration of the important mineral nutrient K, by dividing the specific activity of the sample （Bq/g） by the specific activity of elementary K （31.19 Bq/g）. The method implies the γ rays detection emitted by natural ^40K-^40Ar present in foodstuff, by using a 3 × 3＂ low background NaI （TI） scintillation detector coupled to a PC charged with the Maestro Program. When this detection system is calibrated in order to determine its efficiency for 1461 KeV γrays emitted during ^40K-^40Ar decaying, it is possible to measure easily and with enough precision the specific activity due to natural ^40K present in any foodstuff. Once this figure is divided by the constant value of ^40K specific activity of elementary K, the concentration of this element in the foodstuff sample is established. This paper describes the procedure and shows the results obtained with four basic diet products： milk （powdered, light and cream）, eggs （yellow and white）, wheat （whole and refined flour） and corn （whole and cornstarch flour）. The possible application of this study seems to be to establish the necessary threshold to evaluate the importance of any possible radioactive contamination, as well as to measure the concentration of the mineral nutrient K in foodstuff, by means of an easy, practicable method. Also, it might be useful as an experiment for teaching purposes.

Optimization of Blanching Time, Sodium Metabisulphite （Na2S205） Concentration and Processing Time on Vitamin C Content, Microbial Quality and Sensory Characteristics during Canning of Green Pepper （Capsicum sinensis） Using Response Surface Methodology

Response surface methodology and central composite rotatable design （CCRD） for K = 3 were used to investigate the combined effect of blanching time （0-1 min）, processing time （10-30 min） and sodium metabisulphite （Na2S205） salt concentration （0%-2%） on vitamin C content, hardness （texture）, microbial count and color intensity of green pepper （Capsicum sinensis） during canning. Blanching, processing time and sodium metabisulphite （Na2S205） salt concentration all had variable effects on the vitamin C, microbial quality and sensory characteristics of the canned green peppers. Significant （P 〈 0.05） interactions were noted between all the factors with high regression coefficients （78.7%-97.0%）. Increasing processing time caused significant decreases in vitamin C and microbial load of the product. However, salt concentration had only marginal and insignificant effect on the vitamin C content of the canned product. Sensory evaluation on the product showed that both the pre-processing conditions and of blanching and salt concentrations, and the processing time had varied effects on the color and hardness of the products. Hardness of the canned products generally decreased with increasing processing time and blanching time, while only minimal and insignificant effects were noted with blanching time. Increasing blanching time caused significant increasing retention of the dark green color of the peppers with only slight but insignificant increases noted with processing time, while increases in salt concentration consistently reduced the dark green color of the products. The optimum pre-processing and processing conditions that yielded products with high preference and consumer-acceptability were： blanching time of 0 min, processing time of 10 min and sodium metabisulphite concentration of 0.2%.