Solid-Liquid Equilibria of Succinic Acid in Cyclohexanone,Cyclohexanol and Their Mixed Solvents

Solubilities were measured for succinic acid dissolved in cyclohexanone, cyclohexanol and 5 of their mixed solvents at the temperature range from 291.85 K to 358.37 K using a dynamic method. The solubility data were regressed by λh equation, with the average absolute relative deviation 3.47%. The binary interaction parameter is 0.306 7 for the mixed solvent of cyclohexanone and cyclohexanol was determined by correlating the experimental solubilities with the modified λh equation. When the binary interaction parameter was determined, it can be used to extrapolate the solubilities of succinic acid in mixed solvents of cyclohexanone and cyclohexanol at any proportion. The average absolute relative deviation was 7.69% by using the modified λh equation to correlate the solubility data, however, the average absolute relative deviation was 8.89% by using NRTL equation to correlate the solubility data. The results show that the accuracy of the modified λh equation is better than that of the NRTL equation for the solubility of succinic acid in the 5 mixed solvents of cyclohexanone and cyclohexanol.

固态发酵改善棉籽粕品质的研究

通过固态发酵对棉籽粕进行品质改善,并探究其发酵后感官评价、抗营养因子含量及粗蛋白、总酸、酸溶蛋白的变化,为棉籽粕在水产养殖行业中的应用提供理论基础。研究首先探究了枯草芽孢杆菌(Bacillus subtilis)单菌发酵棉籽粕降解其抗营养因子含量的最佳接种量、水料比和时间。研究结果表明,当接种量达到11%为最佳,水料比在(0.6—0.8﹕1)最佳,当发酵时间达到60h后,各抗营养因子的降解率达到最高。随后采用酿酒酵母(Saccharomyces cerevisiae)、植物乳杆菌(Lactobacillus plantarum)配合枯草芽孢杆菌,同时在底物中添加植酸酶及纤维素酶溶液进行混菌固态发酵,并对最佳混菌比例以及酶液添加比例进行探究,结果表明,当枯草芽孢杆菌、酿酒酵母和植物乳杆菌的混菌比例为1﹕1﹕2时综合效果最佳,纤维素酶添加比例为1.25%,植酸酶添加比例为0.10%,降解抗营养因子的效果最佳。随后,以此条件进行混菌发酵,结果表明,混菌发酵棉籽粕在感官评定上要优于单菌发酵,棉籽粕中游离棉酚降解率达到40.13%,植酸降解率达到34.92%,单宁降解率达到40.24%,粗蛋白提升了10.26%,酸溶蛋白提升了59.2%,总酸提升了79.49%。因此,研究为提高棉籽粕的饲用价值提供参考,有利于提高棉籽粕在水产饲料中的添加水平。

乳酸菌固态发酵过程中麦麸组分的动态变化

麦麸是小麦加工的主要副产物,营养丰富且产量大,采用乳酸菌处理麦麸可提高其附加值。为明确乳酸菌发酵对麦麸各组分的影响,作者采用植物乳杆菌、鼠李糖乳杆菌、戊糖片球菌和布氏乳杆菌分别对麦麸进行固态发酵,在48 h内每隔8 h取样,分析可溶性膳食纤维、粗蛋白质、淀粉、总酚、植酸等成分的质量分数及DPPH自由基清除能力的动态变化。结果表明,在麦麸基质中,4株乳酸菌在24 h内生长较为迅速;麦麸经乳酸菌发酵后可溶性膳食纤维质量分数显著提高,其中布氏乳杆菌发酵48 h后可溶性膳食纤维质量分数由4.72%增加至6.58%;随着发酵时间的增加,麦麸中淀粉质量分数逐渐降低,粗蛋白质量分数先增加后降低最后趋于稳定;植物乳杆菌在提高麦麸多酚质量分数方面有更好的效果,多酚质量分数由1.34 mg/g增加至3.86 mg/g,麦麸抗氧化活性显著增加;此外,乳酸菌发酵麦麸可显著降低其植酸质量分数。综合而言,植物乳杆菌和布氏乳杆菌在提高麦麸的营养特性方面具有较好的效果,可有效改善麦麸的综合利用价值。

液体硅肥对青脆李品质的影响

采用液体硅肥对青脆李树进行根部灌施和叶面喷施两种处理方式,果实成熟后测定其单果质量、可溶性固形物、硬度、糖组分、酸组分和维生素C含量。结果表明,施硅肥处理后单果质量、可溶性固形物、果糖和维生素C等品质指标较对照处理有明显提高,根部灌施有效硅34 g(0.4 kg硅肥)、叶面喷施有效硅1.92 g(16 mL硅肥)效果较优。

Surface Acidity of Amorphous Aluminum Hydroxide

The surface acidity of synthetic amorphous AI hydroxide was determined by acid/base titration with several complementary methods including solution analyses of the reacted solutions and XRD characterization of the reacted solids. The synthetic specimen was characterized to be the amorphous material showing four broad peaks in XRD pattern. XRD analyses of reacted solids after the titration experiments showed that amorphous AI hydroxide rapidly transformed to crystalline bayerite at the alkaline condition （pH〉10）. The solution analyses after and during the titration Ksp=^aAl^3＋/aH^＋^3 ,was 10^10.3. The amount of consumption of added acid or base during the titration experiment was attributed to both the protonation/deprotonation of dissolved AI species and surface hydroxyl group. The surface acidity constants, surface hydroxyl density and specific surface area were estimated by FITEQL 4.0.

Measurement and Correlation for Solubility of Adipic Acid in Several Solvents

Using a laser detecting system, solubility data were measured for adipic acid dissolved in six pure sol-vents, namely, cyclohexanone, cyclohexanol, acetic acid, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethylsulfoxide at the temperature range from 293.15K to 353.15K. All these data were regressed by λ h, NRTL, Wilson, and the modified Wilson models. For the study of six, λ h, NRTL, and the modified Wilson models were found to provide an accurate mathematical representation of the experimental results, with overall average absolute relative deviations between measured and calculated values as 1.74%, 2.06%, and 3.06%, respectively. The results showed that the λ hmodel is the most suitable for description of the solid-liquid equilibrium containing adipic acid.

Determination and Correlation for Solubility of Aromatic Acids in Solvents

Solubility of benzoic acid, terephthalic acid and 2,6-naphthalene dicarboxylic acid in water, acetic acid, N,N-dimethyfformamide, N,N-dimethylacetamide, dimethyl sulphoxide and N-methyl-2-ketopyrrolidine were measured by dynamic method. The solubilities were calculated by UNIFAC group contribution method, in which new groups, BCCOOH and NCCOOH, were introduced to express the activity coefficients of aromatic acids and new interaction parameters of the new groups were expressed as the function of temperature, which were determined from the experimental data. The new interaction parameters provided good calculated result. The experimental data were also correlated with Wilson and λ-h models, and results were compared with present UNIFAC model.

Solubilities of Isophthalic Acid in Acetic Acid ＋ Water Solvent Mixtures

The solubilities of isophthalic acid(1) in binary acetic acid(2)+water(3) solvent mixtures were determined in a pressurized vessel.The temperature range was from 373.2 to 473.2K and the range of the mole fraction of acetic acid in the solvent mixtures was from x2 = 0 to 1.A new method to measure the solubility was developed,which solved the problem of sampling at high temperature.The experimental results indicated that within the temperature range studied,the solubilities of isophthalic acid in all mixtures showed an increasing trend with increasing temperature.The experimental solubilities were correlated by the Buchowski equation,and the calculate results showed good agreement with the experimental solubilities.Furthermore,the mixed solvent systems were found to exhibit a maximum solubility effect on the solubility,which may be attributed to the intermolecular association between the solute and the solvent mixture.The maximum solubility effect was well modeled by the modified Wilson equation.

Solubility of Glutaric Acid in Cyclohexanone,Cyclohexanol,Their Five Mixtures and Acetic Acid

By using the laser-monitoring technique,solid-liquid equilibrium data of glutaric acid in cyclohexanol,cyclohexanone,their five mixed solvents and acetic acid were measured within the temperature range from 292.15K to 354.60K by dynamic method.Empirical formula and λh equation were used to correlate the solubilities of glutaric acid in eight solvents.The maximal average relative deviations were 1.15% and 2.20% by using the em-pirical formula and λh equation to correlate the solubility data.The results showed that the empirical formula and λh model could correlate the solubility data of glutaric acid in eight solvents.In addition,the solubility data of glutaric acid in five mixtures(cyclohexanone+cyclohexanol)could be predicted with the NRTL equation utilizing the pa-rameters of the binary systems.The total average relative deviation was 3.60%.The results indicate that the NRTL equation could well predict the solubilities of glutaric acid in the mixed solvents of cyclohexanone and cyclohexanol.

Determination of soluble solid content and acidity of loquats based on FT-NIR spectroscopy

The near infrared (NIR) spectroscopy technique has been applied in many fields because of its advantages of simple preparation, fast response, and non-destructiveness. We investigated the potential of NIR spectroscopy in diffuse reflectance mode for determining the soluble solid content (SSC) and acidity (pH) of intact loquats. Two cultivars of loquats (Dahongpao and Jiajiaozhong) harvested from two orchards (Tangxi and Chun'an, Zhejiang, China) were used for the measurement of NIR spectra between 800 and 2500 nm. A total of 400 loquats (100 samples of each cultivar from each orchard) were used in this study. Re- lationships between NIR spectra and SSC and acidity of loquats were evaluated using partial least square (PLS) method. Spectra preprocessing options included the first and second derivatives, multiple scatter correction (MSC), and the standard normal variate (SNV). Three separate spectral windows identified as full NIR (800～2500 nm), short NIR (800～1100 nm), and long NIR (1100～2500 nm) were studied in factorial combination with the preprocessing options. The models gave relatively good predic- tions of the SSC of loquats, with root mean square error of prediction (RMSEP) values of 1.21, 1.00, 0.965, and 1.16 °Brix for Tangxi-Dahongpao, Tangxi-Jiajiaozhong, Chun'an-Dahongpao, and Chun'an-Jiajiaozhong, respectively. The acidity prediction was not satisfactory, with the RMSEP of 0.382, 0.194, 0.388, and 0.361 for the above four loquats, respectively. The results indicate that NIR diffuse reflectance spectroscopy can be used to predict the SSC and acidity of loquat fruit.

一种适用于碳酸盐岩储层的无固相易酸溶新型钻井液

鄂尔多斯盆地大牛地气田下古生界碳酸盐岩储层微裂缝发育,原钾铵基钻井液固相易进入微裂缝造成储层伤害且不易解除,勘探开发实践证实酸化后渗透率恢复值仅为51.40%,直接影响了该地区天然气的勘探开发效果。为此,针对大牛地气田马五5亚段碳酸盐岩储层黏土含量低、井壁稳定性好和完井酸压后增产不理想等情况,优选了酸溶性羧甲基纤维素钠盐和抗高温淀粉等天然高分子处理剂,配套了杀菌剂和润滑剂,构建了一种低密度无固相易酸溶新型钻井液。研究结果表明:①与原钾铵基钻井液相比,低密度无固相易酸溶钻井液具有无固相、易酸溶和返排快等特点,实钻密度下降0.04~0.06 g/cm^(3),固相含量小于2%,且与储层配伍性良好,可有效预防并减小钻井过程钻井液对储层的伤害;②该钻井液聚合物酸溶率95.45%,泥饼酸溶率100%,渗透率恢复值比钾铵基钻井液提升了43.89%,有利于下古生界碳酸盐岩气藏天然气渗流通道微裂缝的疏通恢复。结论认为:①该钻井液现场完钻10口水平井,同样的复合加砂酸压后,产气量较邻井提高76%;②该钻井液从源头保护储层避免伤害,可满足大牛地气田碳酸盐岩钻井储层保护的需求,为有效提升碳酸盐岩天然气的勘探开发效果提供了技术支撑。

冷冻速度对苹果贮期品质的影响

为了研究不同冷冻处理速度对苹果贮藏品质的影响,分别采用0.5℃/min和3.5℃/min两种冷冻速度对苹果进行冷冻处理,分析苹果贮藏期间的品质变化。结果表明:冷冻处理速度显著影响苹果的贮藏品质。高冷冻速度处理的苹果品质损伤更小且苹果硬度、可溶性固形物、维生素C含量更高,口感、营养价值更好;同时L^(*)值更高,a^(*)值、b^(*)值更低,外表面颜色保持得更鲜艳。

酸碱滴定法测定复合固体推进剂燃烧产物中氯化氢

设计了一套固体推进剂燃烧产物收集装置,建立了酸碱滴定法测定燃烧产物中氯化氢含量方法。在密闭燃烧产物收集装置中,采用Φ36 mm实验发动机试车,加入1 L 1 mol/L氢氧化钠溶液吸收燃烧产物,并用氢氧化钠溶液将气体收集罐内部清洗干净,合并吸收液并准确称取质量。吸收液静置17 h后准确称取上清液约20 g进行测试。以甲基橙为指示剂,控制滴定终点pH在3.4左右,使Al^(3+)和CO_(2)以进入体系的初始状态存在于终点体系中,消除Al^(3+)和CO_(2)的影响,用0.1 mol/L盐酸标准滴定溶液滴定吸收液中剩余的氢氧化钠,得到推进剂燃烧产物中氯化氢含量。该法测定结果的相对标准偏差小于2%(n=6),测定结果与理论计算值的相对偏差在0~-1.5%之间,燃烧产物收集装置设计合理。

一株枯草芽孢杆菌进行饲料固态发酵的条件优化

文章选用一株枯草芽孢杆菌B591对蛋鸡配合饲料基础料进行固态发酵,通过对发酵条件进行优化,得到最优发酵条件为:发酵时间为14 d,接种量为6×10^(8)CFU/kg,料水比为1∶0.5,硫酸铵添加量为2.5%。并测定了优化发酵条件下的发酵饲料质量,发酵后饲料的pH显著降低,有效活菌数可达到1.83×10^(11)CFU/kg,酸溶蛋白/粗蛋白含量达到33.66%。希望可以通过该研究,为后续进行多菌种固态发酵提供一定的参考。

烧成温度对菱镁矿尾矿合成镁橄榄石性能的影响

以菱镁矿尾矿和硅石为原料,采用固相烧结法合成陶粒支撑剂用镁橄榄石原料,不仅有利于菱镁矿尾矿的二次资源化利用,还可代替天然镁橄榄石作为陶粒支撑剂原料,为其制备原料提供新的方向。本文通过对物相组成、显微结构、常温物理性能等表征,探究了不同烧成温度对合成镁橄榄石性能的影响,同时横向对比了不同烧成温度下试样的酸溶解度。结果表明,当烧成温度为1 400~1 550℃、恒温时间为3 h时,试样中的主物相均为镁橄榄石;随着烧成温度的提高,镁橄榄石晶粒不断增大,提高了试样的常温物理性能与耐酸性能,但过高的烧成温度会导致试样中玻璃相含量的增加,影响其性能。当烧成温度为1 500℃时,试样常温力学性能达到最大值,酸溶解度最低。

‘东魁’杨梅果实色泽指标及果实内在品质相关性

研究‘东魁’杨梅不同成熟程度果实色泽指标、内在品质指标的差异,探讨色泽指标和果实内在品质之间的相关性,为杨梅果实的外观色泽评判和果实的优质采收提供一定的参考依据。以露地、大棚和高山网室4个基地栽培的‘东魁’杨梅为试材,对成熟期不同成熟程度‘东魁’杨梅果实的色泽指标L^(*)、a^(*)、b^(*)、a^(*)/b^(*)、C、H、CIRG值以及果实单果重、硬度、可溶性固形物含量、可滴定酸含量、固酸比等品质指标进行测定和分析。结果表明,随着果实成熟度提高,颜色由红色至深红色、紫红色、紫黑色不断加深,果实色泽指标L^(*)、a^(*)、b^(*)、C及H值呈降低趋势,a^(*)/b^(*)和CIRG值呈增大趋势,而果实可滴定酸含量呈降低趋势,固酸比呈增大趋势。其中CIRG值在4个基地的4个不同果实颜色中均表现出显著差异,能较好地反映杨梅果实颜色的差异,即CIRG值介于2.36~3.43果实为红色,介于3.69~4.14果实为深红色,介于4.80~5.46果实为紫红色,介于5.58~7.69果实为紫黑色,且在4个基地中CIRG值与果实固酸比均呈极显著正相关。研究认为CIRG值可用于‘东魁’杨梅外观色泽、成熟度和内在品质的量化评价。

天津地区葡萄物候期观察和果实糖酸含量变化分析

为明确不同葡萄品种在天津地区最佳采收时间以及果实品质差异,选择6种葡萄作为试验材料,观测植株生长及果实发育情况,使用天农葡萄数据库进行试验数据的记录及分析。结果表明:不同品种葡萄间动态变化趋势基本一致,夏黑与红富士葡萄可溶性固形物含量显著高于寒香蜜、红巴拉多和红宝石;红巴拉多、黑巴拉多可滴定酸含量显著低于其他品种;固酸比越高,越接近果实成熟,红巴拉多和黑巴拉多显著高于其他品种;红宝石单果重显著低于其他品种。不同品种间果实生长发育所需时间不同,其中寒香蜜最短(90 d),红宝石所需时间最长(115 d)。在本研究的6个葡萄品种中,红巴拉多、黑巴拉多果实品质较高,糖酸含量适中,果粒较大。寒香蜜在采收期可滴定酸含量仍较高,建议适当延长采收期。综上,本研究为天津地区鲜食葡萄栽培提供了理论依据和数据参考。

钙镁叶面肥缓解妃子笑荔枝果肉退糖现象的呼吸机理

【目的】探讨叶面喷施钙镁肥对妃子笑荔枝果肉糖酵解(EMP)—三羧酸循环(TCA)途径呼吸速率的影响,为荔枝生产提供理论参考。【方法】设置以树冠喷布0.3%CaCl2水溶液(Ca)、0.3%MgCl2水溶液(Mg)、0.3%CaCl2+0.3%MgCl2水溶液(Ca+Mg)的3组处理,以树冠喷布清水为对照(CK),测定、比较不同发育期荔枝果肉风味品质主要指标、EMP-TCA途径呼吸速率及其关键酶活性的动态变化。【结果】荔枝果肉可溶性糖含量在35~56 d呈上升趋势,在花后63 d之后,除Ca+Mg处理的果肉可溶性糖含量未显著下降(P>0.05,下同)而缓解退糖现象外,其他处理均出现退糖现象。所有处理的果肉可滴定酸含量在采收期前后均无显著变化,且相互间无显著差异;Ca处理和Ca+Mg处理的EMP途径呼吸速率显著低于Mg处理和CK(P<0.05,下同),而在TCA途径呼吸速率上,Ca+Mg处理显著低于Ca处理,故Ca+Mg处理通过抑制EMP-TCA途径呼吸速率进而抑制果肉总呼吸速率;采收期前后,Ca+Mg处理的磷酸已糖异构酶(GPI)、琥珀酸脱氢酶(SDH)和苹果酸酶(NADP-ME)等活性均显著低于CK;Ca处理对GPI活性具有抑制作用,对PDC活性呈现促进作用;Ca处理和Mg处理的NADP-ME活性显著高于Ca+Mg处理和CK。【结论】Ca+Mg处理通过抑制妃子笑荔枝果肉GPI、SDH和NADP-ME活性而分别抑制EMP和TCA途径,进而降低EMP-TCA途径有氧呼吸速率,减少果肉糖分呼吸损耗,从而减缓果肉退糖现象。

近红外导数光谱测定赣南脐橙可溶性固形物及固酸比

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