混合菌利用制酒废水产生微生物絮凝剂的研究

从成都某污水处理厂活性污泥中分离、筛选了2株絮凝剂产生茵,初步鉴定为蜡状芽孢杆菌(Bacillus cereus)和膜璞毕赤酵母(Pichia membranifaciens).利用制酒废水替代成本较高的传统培养基对这两株菌的混合菌(HXJ-1)的最佳产絮条件和絮凝剂的最佳絮凝条件进行了研究,得出了HXJ-1的最佳产絮务件:废水COD为12 000 mg/L,C/N值为20:1,相对接种量为10%(体积分数,菌体浓度为1×108个/L),初始pH值为3.6(制酒废水自然pH),摇床转速为120r/min,培养温度为30℃.在此条件下,发酵24 h所产生的絮凝剂XJBF-1)对高岭土悬浊液的絮凝率平均为89.50%.以浓度为l g/L的高岭土悬浊液(93 mL)为试验对象,得出了XJBF-1的最佳絮凝条件,即:絮凝体系的pH值为7;絮凝剂用量为2 mL;以l%的CaCl2为助凝剂,其投量为5mL.     

SOCKS协议在防火墙中的应用研究

阐述了采用实现SOCKS协议的一种新型防火墙系统,较为详细地论述了其架构与功能,分析了SOCKS协议实现原理和过程。围绕SOCKS客户机与SOCKS服务器,给出了请求与响应格式及其建立连接实现功能的详细步骤,对比说明了SOCKS与Proxy的区别,突出了该系统的特点及其优越性。     

Transformations of Cyclohexene Oxide over Silica-Supported Cu,Pd, and Rh Catalysts in H2/D2Atmosphere

Transformations of cyclohexene oxide were studied in a recirculation reactor and a flow system over silica-supported transition and early transition metal catalysts. Hydrogen pressure dependence of the transformations was measured over Cu/SiO₂at 403 K in the 0–98.7 kPa range. Deuterium distribution in the reactant and products were determined at 20 kPa D₂pressure. The reactions were studied in the flow reactor under D₂stream over Cu/SiO₂(373 K, 403 K, 443 K, 523 K), Pd/SiO₂(403 K), and Rh/SiO₂(403 K) catalysts too. Deuterium distributions were determined at the commonly used 403 K. Over each catalyst, in both reactor types three main transformation pathways were found. Single C-O scission occurred via isomerization and hydrogenation. Double C-O cleavage, that is, deoxygenation was also found to be important. Product distribution varied from catalyst to catalyst and it was influenced by the conditions, as well as the reactor types. Deuterium distribution revealed significant differences in the elementary surface processes over the catalysts. Detailed mechanistic interpretation of the transformations is offered.     

川中丘陵区冬作不同品种马铃薯鲜切加工适宜性评价

以四川省川中丘陵区冬作马铃薯10个主栽品种为试验材料,考察了不同品种经鲜切加工后常温贮藏条件下总体感官质量、切片表面色差、褐变度和多酚氧化酶活性。结果表明,不同品种鲜切马铃薯在贮藏过程中各项指标均存在明显差异;中薯2号在贮藏过程中总体感官值相对较高,常温贮藏至第4 d时仍具有一定的商品性,而川芋802在贮藏至第2 d时外观商品性就接近5分(商品临界点);中薯2号和川芋10号的色差变化值相对较小,而川芋50和川芋802变化较大;川芋10号、费乌瑞它和青薯9号贮藏过程中褐变度相对较低;对PPO活性进行聚类分析将10个供试品种分为两个大类;综合多项测试指标表明,中薯2号和川芋10号鲜切加工后常温贮藏过程中产品品质较好,抗褐变能力较强,而川芋802和川芋50较易发生褐变,该研究结果可为马铃薯鲜切加工原料的选择提供参考依据。     

Selectivity of some zeolites for adsorption of atmospheric gases

Dimensionless Henry constants, sorption energies and separation factors are reported for the atmospheric gases (N₂, O₂ and Ar) on several different zeolites. The extent to which the pattern of selectivity can be understood in terms of differences in the basic molecular properties of the three sorbates is briefly considered.     

Grüneisen parameters of a hexagonal close-packed lattice

A program has been developed to study the effect of central forces on the Grüneisen parameters of a hexagonal close-packed lattice. Calculations are presented for the normal modes, the contributions to the Grüneisen parameters, polarization vectors and the two independent effective Grüneisen parameters, γ′ and γ″, for this lattice as a function of T/θ_D.     

Fractionation and characterization of brown colored components in heat treatment liquor of waste sludge

To characterize the colored components in the heat treatment liquor of waste sludge, three distinct liquor samples were fractionated into four fractions (I–IV) by HCl-precipitation and with XAD-7 resin. In all the samples tested fractions III, which were acid-soluble and eluted from the resin with methanol, contained 55–77% of the total color. In one sample fraction I, which was acid-insoluble, also had relatively high color content (22% of the total). Therefore, we defined fractions III and I as main color fractions of the heat treatment liquor. The color of fraction I decreased, but that of fraction III did not decrease during incubation of the liquor with activated sludge. Furthermore, the color of fraction I decreased as that of fraction III increased during the incubation. It was suggested that the colored components in fraction I are converted into the colored components fractionated into fraction III through the biological treatment. Molecular shape of the colored components in fractions I and III were affected by ionic strength: their molecular weight fell in higher ionic strength solvent. The two colored components were degraded with alkaline hydrogen peroxide. Identification of their degradation products revealed that both of them had partially the same chemical structures as the melanoidin pigment synthesized from glucose and glycine, and they had considerable common structures regardless of their presence in different fractions I and III.     

高效液相色谱测定番茄制品中的三种功能性脂肪酸

通过高效液相色谱-质谱技术和高效液相色谱技术对番茄制品中9-羟基-10(E),12(Z)-十八碳二烯酸、9-羰基-10(E),12(Z)-十八碳二烯酸和9-羰基-10(E),12(E)-十八碳二烯酸三种功能性脂肪酸进行定性定量分析。结果表明,在色谱柱为Eclipse XDB-C18(4.6 mm×250 mm,5 μm),流动相为0.005%的三氟乙酸水溶液和0.005%的三氟乙酸乙腈溶液,检测波长为234、280 nm的条件下,番茄制品中的三种脂肪酸在20 min内得到较好分离,重复性好(RSD ≤ 2.13%),精密度高(RSD ≤ 0.70%),稳定性好(RSD ≤ 0.98%),加标回收结果准确可靠(平均回收率分别为99.78%、99.70%、99.39%,RSD ≤ 3.38%)。该色谱方法快速、准确、可靠;测试结果表明,新鲜番茄中不含有这三种功能性脂肪酸,其仅存在于番茄制品中,且加工工艺对其含量影响较大;此外9-羟基-10(E),12(Z)-十八碳二烯酸为首次在番茄制品中发现。     

超高效液相色谱-荧光检测法测定水果中3种萘衍生物

建立了超高效液相色谱-荧光检测法同时测定水果中1-萘乙酰胺(NAD)、1-萘乙酸(NAA)和2-萘氧乙酸(2-NOA)3种萘衍生物的方法。样品经2%甲酸-乙腈提取,QuEChERS法净化,用ACQUITY UPLC BEH phenyl色谱柱分离,超高效液相色谱荧光检测器测定。3种化合物质量浓度在0.005~1.0 mg/L范围内,与色谱峰面积呈良好的线性关系,相关系数(r)>0.9999。当样品中添加水平为0.01、0.1和1.0 mg/kg时,回收率为78.3%~95.3%,相对标准偏差(RSD)为2.8%~9.5%,方法检出限(LOD)为0.002~0.003 mg/kg,方法定量限(LOD)为0.006~0.01 mg/kg。该方法简便、灵敏、准确,适合用于水果中NAD、NAA、2-NOA的同时测定。