静电纺丝法制备铝掺杂ZnO纳米纤维的研究

以聚乙烯醇(PVA)作为络合剂与醋酸锌/醋酸铝反应制得纺丝溶液,采用静电纺丝法制备聚乙烯醇(PVA)/醋酸锌醋酸铝复合纤维,经煅烧后得到直径为100~700nm具有高的比表面积的ZnO∶A l纳米纤维.分别采用X射线粉末衍射(XRD)、扫描电镜(SEM)、光致发光(PL)等分析测试手段对ZnO∶A l纳米纤维的表面形貌、晶体结构、发光性能进行表征.XRD结果表明,ZnO∶A l纳米纤维为六方纤锌矿结构,PL谱表明ZnO∶A l纳米纤维具有较强的紫外发射性能.     

Au纳米颗粒修饰的多孔单晶ZnO纳米片及其甲醛敏感特性研究

以醋酸锌和尿素作为原料,采用水热法结合热处理工艺制备了多孔单晶ZnO纳米片;采用柠檬酸还原法制备了Au纳米颗粒.然后,在液相中将聚乙烯亚胺修饰在ZnO纳米片上,再利用静电作用将Au纳米颗粒与聚乙烯亚胺结合,将其修饰在ZnO纳米片上.XRD,FE-SEM和EDS表征证明了多孔单晶ZnO纳米结构的存在和Au纳米颗粒修饰成功.气敏实验结果显示,这种Au纳米颗粒修饰的多孔单晶ZnO纳米片对甲醛具有良好的选择性,其最佳工作温度为300℃,在10~500×10-6浓度范围内具有良好的线性响应.     

溶胶-凝胶法制备氮掺杂纳米ZnO及其抗菌性能研究

以硝酸锌为锌源,氨水为沉淀剂,壳聚糖为添加剂,通过溶胶-凝胶法制备出粒度小、形貌分布均匀、氮掺杂量高的肤色氮掺杂纳米ZnO晶体,研究了壳聚糖对产品微观结构及性能的影响.采用SEM、TEM、XRD和IR等手段对产品微观结构进行了表征,对其抗菌性能进行了评价.结果表明:添加壳聚糖有利于凝胶的快速形成,而且可通过壳聚糖的添加量有效控制纳米晶体的大小、形貌以及氮掺杂量,最终得到平均粒径为30 nm的球形氮掺杂纳米ZnO晶体,晶相与标准立方相ZnO衍射峰完全一致,没有其他杂相出现,颜色为均匀的红色.和普通的纳米ZnO晶体相比,抑菌结果显示合成的氮掺杂纳米ZnO晶体对大肠杆菌具有优良的抗菌性.     

不同形貌纳米ZnO的制备、掺杂及在改性涤纶织物中的应用

以氯化锌、氢氧化钠、硝酸铝及硝酸钇为原料,采用低温水热法制备不同形貌的纳米ZnO及Al-Y修饰ZnO复合物,并使用掺杂后的ZnO作用于改性涤纶织物。采用扫描电子显微镜、X射线衍射仪和紫外-可见光漫反射等方法对所制样品进行表征。结果表明:通过控制Zn2+/NaOH配比,利用水热法制得片状、花状和棒状的纳米ZnO,其中片状ZnO的光催化活性较好,在紫外光下照射120 min,对亚甲基蓝(MB)的降解率为86.68%。涤纶织物经3%Al-3%Y共修饰片状ZnO掺杂后,在紫外光下照射120 min,对MB的降解率达到92.30%,紫外线防护指数达50+,具备良好的光催化与抗紫外线性能。     

纳米氧化锌抗菌纸的制备及其抗菌性能的研究

采用浸渍法使Zn~(2+)进入纸基纤维内,然后通过一步水热法合成出负载有不同形貌的纳米氧化锌(ZnO)抗菌纸,在保证抗菌性能的同时实现其固定化,避免二次污染。探究了不同制备工艺条件对纳米ZnO抗菌纸的形貌、抗菌性能和物理性能的影响,并采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对产物的结构和形貌进行表征。结果表明,抗菌纸上负载的ZnO纳米颗粒均为结晶良好的六方纤锌矿结构,不同制备条件生成的纳米颗粒结构差异巨大,有棒状、针状、米粒状等;以抑菌率为主要指标,通过正交实验得出的最佳制备工艺为:浸渍温度70℃、浸渍时间2 min、ZnCl_2溶液质量分数45%、NaOH溶液pH值12;在此条件下制备的纳米ZnO抗菌纸对大肠杆菌的抑菌率达到76. 9%。     

纳米氧化锌的制备与光催化性能的研究

氧化锌是一种高效、无毒性、价格低廉的重要光催化剂。以乙酸锌和草酸为原料,采用溶胶-凝胶法制备纳米ZnO。采用XRD、SEM对纳米ZnO的结构和形貌进行了分析,结果表明,不同焙烧温度下得到的纳米氧化锌均为六方晶系的纤锌矿结构,平均粒径大小在10～55nm。样品颗粒形状基本上为球形,样品颗粒大小比较均匀。以甲基橙溶液为模拟污染物对纳米ZnO的光催化性能进行了研究,结果表明,焙烧温度对纳米氧化锌的光催化性能有一定影响,不同温度下纳米ZnO的光催化效率不同,在焙烧温度450℃时,催化效果较好,可以达到61%。     

CuS/ZnO纳米复合材料的制备及其应用研究

以Zn(NO3)2·6H2O和尿素为原料,通过液相沉淀法成功制备了纳米ZnO;以Cu(Ac)2、Na2S为原料,通过液相法制备出纳米CuS;将2者机械研磨制备出CuS/ZnO纳米复合材料.运用XRD、TEM和XPS对产物结构、形貌与价态等进行了表征.结果表明,样品为棒状的CuS与圆球状的ZnO结合而成,粒径在33 nm左右.通过光催化试验发现,CuS能显著地提高纳米ZnO的光催化性能.当CuS的掺杂量为0.5%时,催化效果最好.另外,CuS/ZnO纳米复合材料具有良好的光催化循环利用率.抗菌试验表明,复合物中的CuS并没有改变ZnO优异的抗菌性能.     

磁控溅射Ag/ZnO纳米薄膜涤纶织物的制备及其性能

为探讨织物结构对表面沉积纳米复合薄膜形貌及性能的影响,采用直流射频共溅法,以不同组织结构纯涤纶织物为基材,分别以金属银(Ag)与锌(Zn)为靶材,制备Ag/ZnO纳米薄膜。对表面沉积Ag/ZnO薄膜的涤纶织物的形貌结构,沉积颜色、防紫外线性能及电磁屏蔽性能进行表征。实验结果表明:非织造布表面薄膜颗粒分布较为均匀,机织布表面纳米颗粒最不平整,针织布表面纳米颗粒粒径较小,并存在部分团簇颗粒;试样表面Ag衍射峰较明显,但ZnO依然以非晶态形式存在;针织布表面沉积Ag/ZnO薄膜后,其明度最小,颜色较暗;以非织造布为基材的试样其防紫外线性能及电磁屏蔽效果最明显。     

纳米ZnO的改性与表征

以尿素、醋酸锌为原料,采用微波水解法制备纳米ZnO,利用SiO2对纳米ZnO包覆改性,并通过XRD,TEM,分光光度计等对纳米ZnO的形状和尺寸进行表征,对其性能进行测试.结果表明,纳米ZnO改性的最佳工艺条件为：w（SiO2）=3%,时间0.5 h,温度80℃.纳米ZnO的比表面积改性前为20.21 m^2/g,改性后为14.65 m^2/g,且改性后纳米ZnO的吸光度明显提高.TEM显示纳米ZnO表面有明显的包覆层,说明用SiO2包覆纳米ZnO是可行的.     

纳米ZnO的改性与表征

以尿素、醋酸锌为原料,采用微波水解法制备纳米ZnO,利用SiO2对纳米ZnO包覆改性,并通过XRD,TEM,分光光度计等对纳米ZnO的形状和尺寸进行表征,对其性能进行测试.结果表明,纳米ZnO改性的最佳工艺条件为:w(SiO2)=3%,时间0.5 h,温度80℃.纳米ZnO的比表面积改性前为20.21 m2/g,改性后为14.65 m2/g,且改性后纳米ZnO的吸光度明显提高.TEM显示纳米ZnO表面有明显的包覆层,说明用SiO2包覆纳米ZnO是可行的.     

Preparation of Hydroxypropyl Methylcellulose Acetate Succinate with a Narrow Molecular Weight Dispersion

Hydroxypropyl methylcellulose acetate succinate (HPMCAS) was successfully synthesized from the reaction of hydroxypropyl methylcellulose with succinic anhydride and acetic anhydride in an acetone/pyridine system. Products with different contents of succinyl groups and acetyl groups were prepared by varying the reaction conditions. In the acetone/pyridine system, equipment corrosion does not occur, the product is easy to wash, and the solvent can be recycled. By varying the concentration of the esterifying agents, products with different ratios of acidic groups can be obtained. Under the optimum conditions, the obtained products had an average molecular weight between 5.39×10⁴ and 5.41×10⁴, a number average molecular weight from 4.97×10⁴ to 5.13×10⁴, and a polydispersity index from 1.05 to 1.08. The products dissolved well in acetone and methanol, and formed films on a mold. The films had good pH-sensitivity, tensile strength, and thermal stability. The formed films could dissolve in solutions with a pH value ranging from 5.4 to 6.4, and are therefore suitable for use as an enteric coating for pharmaceutical dosage forms.     

餐厨废油和醇/酮添加物共裂化制备生物基燃料油

以HY、HZSM-5、MCM-41分子筛为催化剂,通过向餐厨废油中添加5%的乙醇或丙酮进行共裂化反应制备生物基燃料油,对液体产物的品质指标进行了测定,并对其成分进行了GC-MS分析。结果表明:在HY和MCM-41催化条件下,添加醇/酮后裂化反应优化效果明显,液体产物密度、酸值、皂化值均降低,产率升高,催化剂结焦率和产气量均降低,而在HZSM-5催化条件下,优化效果不明显;GC-MS分析表明,在添加乙醇后液体产物中烷烃含量增加到24.93%,添加丙酮后液体产物中芳香烃含量增加到70.27%,含氧化合物含量降低至2.38%。研究表明催化裂化时加入醇/酮可以在不同程度上改善生物基燃料油的产品品质,并对生物基燃料油的成分种类起到很强的选择性。     

Simultaneous determination of N-methylcarbamate pesticides and their metabolites in agricultural products

We investigated the determination of N-methylcarbamate pesticides and their metabolites in agricultural products by HPLC with post-column fluorescence detection after clean-up with an SPE cartridge. The homogenate of agricultural products was extracted with acetone. The crude extract was partitioned between 5% sodium chloride solution and dichloromethane, and the dichloromethane layer was concentrated to dryness. The residue was dissolved with a mixture of acetone and n-hexane, and purified by using Supelclean ENVI-Carb SPE, Bond Elut Extraction Cartridge PSA and SAX in series with a mixture of acetone and n-hexane. N-Methylcarbamate pesticide was analyzed by HPLC with post-column reaction and fluoresce detection. N-Methylcarbamate pesticide in citrus fruits and various kinds of agricultural products could be analyzed accurately by the presented method. Recoveries of N-methylcarbamate pesticides added to several agricultural products at the level of 0.10 ppm were mostly in the range of 60-110%. The limit of detection was 0.005 ppm.     

光皮木瓜原花青素提取物对不同饱和度油脂氧化稳定性的影响

以光皮木瓜为原料,采用水、50%乙醇、60%丙酮提取光皮木瓜原花青素。利用超高效液相色谱-质谱联用仪对3种原花青素提取物进行成分分析,同时采用Schaal加速氧化的方法考察其对3种不同饱和度油脂（花生油、葵花籽油、亚麻籽油）氧化稳定性的影响。结果表明：3种原花青素提取物中的原花青素主要由原花青素高聚体和低聚体组成,其中高聚体含量均在90%以上,低聚体以原花青素二聚体为主。在加速氧化过程中,3种原花青素提取物均能有效延缓油脂的氧化。在花生油中,与空白样品相比,水提取物能够使油脂过氧化值下降33.00%,显著高于乙醇提取物（1866%）和丙酮提取物（9.15%）。在葵花籽油和亚麻籽油中,乙醇提取物和丙酮提取物对油脂氧化的抑制能力相似且强于水提取物。光皮木瓜原花青素可以作为一种天然抗氧化剂,用于提高油脂的氧化稳定性。     

Antioxidant properties of extracts from Ginkgo biloba leaves in meatballs

The aim was to determine the effect of Ginkgo leaf extracts on the stability of lipids and cholesterol in pork meatballs over 21 days of refrigerated storage. The antioxidants used were characterized by their antioxidant activity towards lipids and cholesterol. Extracts were prepared from green and yellow leaves from Ginkgo biloba L. trees. Water, acetone and ethanol were used as extractants. The extracts showed stabilizing effects on both lipid and cholesterol oxidation processes. The lipid oxidation process of pork meatballs was mostly inhibited by the aqueous and ethanolic extracts of the yellow leaves. Their antioxidant activity was higher than that of BHT. All the extracts had a stabilizing effect on cholesterol and most of them inhibited the formation of oxidized derivatives. The acetone and ethanol extracts of green leaves and the ethanol extract of yellow leaves inhibited the formation of cholesterol oxidation products formation most effectively.     

Functional properties of proteins isolated from phorbol ester-free physic nut (Jatropha curcas L.) seed cake

Phorbol ester-free physic nut (Jatropha curcas L.) seed cake is a nutritious protein source. Functional properties of the protein isolates obtained from various protein precipitation methods were investigated. Proteins isolated from the seed cake by ammonium sulfate gave the highest yield. The solubility of all proteins increased with increasing pH with their maximum and minimum solubility at pH of 12.0 and 4.0, respectively. The protein prepared by ethanol provided the maximum water holding capacity (3.34 mL water/g protein). The oil binding capacities of all proteins were 1.96–2.03 mL oil/g protein. The protein precipitated by ethanol showed higher emulsion activity and stability than that precipitated by acetone and ammonium sulfate. The protein obtained from ammonium sulfate gave the highest foam capacity, while the protein from acetone had the highest foam stability. Different functional properties of the proteins were achieved by various protein precipitation methods. The protein isolate obtained from each method could serve as a food ingredient applied to food products requiring a specific functional property.     

Milling of solvent-extracted wheat,semolina and flour. I.—Effect on endosperm fragmentation and protein shifting

The degree of endosperm fragmentation in milled flour and degree of protein shifting in air-classified fractions were slightly augmented by pre-milling treatment of Manitoba wheat and milled products with acetone; they were more markedly affected by treatment with methanol if the residual solvent was promptly removed after treatment. In these circumstances, gluten could be recovered from the flour. Methanol, acting upon wheat, semolina or flour for extended periods of time, had a deleterious effect on the protein, severely reducing endosperm fragmentation and preventing the recovery of recognisable gluten from the milled flour; aqueous butanol had a similar effect.     

丙酮法提取菜籽饼多酚及体外抗氧化性研究

以菜籽饼为原料,探讨了采用丙酮法提取菜籽饼多酚的工艺及丙酮多酚提取液的体外抗氧化性。以多酚得率为考察指标,选择丙酮体积分数、提取温度、料液比及提取时间进行单因素及正交试验,确定了丙酮法提取菜籽饼多酚的最优工艺条件:提取温度70℃,料液比1∶12,提取时间30 min,丙酮体积分数35%,在此条件下菜籽饼多酚得率为20.64 mg/g。以鞣酸、维生素C为对照,通过测定丙酮多酚提取液的还原能力及对DPPH.的清除能力,结果表明,丙酮多酚提取液具有一定的体外抗氧化能力。     

高效液相色谱法测定南极磷虾及其制品中虾青素的含量

目的建立一种准确测定南极磷虾及其制品中虾青素含量的高效液相色谱方法。方法样品经无水MgSO_4去除水分,以丙酮提取目标物,200 mg N-丙基乙二胺(PSA)填料分散固相萃取净化,经0.02 mol/L氢氧化钠甲醇溶液皂化12~16 h后,经YMC-Carotenoid C30色谱柱分离,经甲醇、叔丁基甲基醚和1%磷酸水溶液的流动相进行梯度洗脱,紫外检测器测定。结果南极磷虾和南极磷虾粉中虾青素的定量限分别为2.5 mg/kg和5 mg/kg;在0.1~10 mg/L时,全反式虾青素的线性关系良好(r~20.999);该方法的加标回收率在77.9%~91.3%之间,相对标准偏差为3.42%~8.75%。不同磷虾粉产品中虾青素的含量差异很大。结论本方法操作简便、准确,适用于南极磷虾及其制品中虾青素含量的分析。     

不同萃取方法-气相色谱法测定皮革制品中五氯苯酚的比较

以丙酮混合物为萃取溶剂,分别采用超声萃取法、索氏萃取法和微波辅助萃取法对皮革制品中五氯苯酚进行萃取,采用气相色谱法进行分析,比较各萃取方法的萃取效果。结果表明,微波辅助萃取效果最好。并对实际样品进行分析测定,结果表明,三种萃取方法的分析结果之间无显著差异。