腊梅花挥发油化学成分分析

水蒸气蒸馏法提取腊梅花挥发油,GC-MS分析鉴定其化学成分,并计算各组分的相对含量,分离鉴定了其中65个组分,其主要成分为α-法呢烯(9.833%),大香叶烯D(9.693%),石竹烯(8.757%),和β-揽香烯(7.252%)。     

蒙药新-Ⅱ中微量硒的测定

采用硒 -硫氰酸钾 -罗丹明 B-明胶 - OP体系分光光度法测定蒙药新 - 中微量硒。其含量为 6 .6—7.3μg· g-1 ,回收率为 94 %— 95 %。     

SPME-GC-MS分析瀑布毛峰茶叶的赋香成分

采用顶空-固相微萃取法(SPME)从瀑布毛峰茶叶中提取挥发性成分,用气相色谱-质谱法(GC-MS)分析其组成。从一级和特级茶叶中分别鉴定了相对含量大于0.50%的化合物48个和41个,其中共同组分27个。一级瀑布毛峰茶叶的主要挥发性成分有壬醛(9.22%),芳樟醇(4.75%),牛儿醇(4.07%),(Z)-3-己烯-1-醇(3.53%),十一醛(3.16%),邻苯二甲酸二异丁酯(2.94%),十六烷(2.35%),己醛(2.00%),1-辛醇(1.97%),6-甲基-5-庚烯-2-酮(1.86%)。特级瀑布毛峰茶叶的主要挥发性成分有:壬醛(8.85%),1-辛烯-3-醇(6.37%),十一醛(4.81%),2,5,5-三甲基-1-己烯(2.84%),辛醛(2.73%),1-辛醇(2.63%),6-甲基-5-庚烯-2-酮(2.60%),芳樟醇(2.20%),1-戊醇(2.20%),己醛(2.16%)。两个等级的瀑布毛峰茶的主要挥发性成分大致相同,但各成分的含量存在一定差异。     

蒙药兴格各其满都啦-21中多糖的提取与含量测定

采用热水提取-乙醇沉淀的方法从蒙药兴格各其满都啦-21中提取多糖,用硫酸-苯酚法进行了糖含量的测定,求得其线性回归方程为y=0.00976x＋0.451,相关系数为r=0.9996,平均回收率为99.2%,RSD=0.80%（n=5）。     

蒙成药沏其日甘-5中多糖的测定

介绍了提取沏其日甘-5中水溶性多糖、碱溶性多糖的提取方法,并用硫酸-苯酚法测定了沏其日甘-5中总糖、水溶性多糖、碱溶性多糖、不溶性多糖和游离糖的含量.平均回收率为103.2%,RSD为0.91%.     

栽培宽叶缬草中的精油成分分析

采用水蒸气蒸馏法提取宽叶缬草精油,气相色谱-质谱分析其组成。从栽培宽叶缬草的精油成分中鉴定出6个化合物,共占精油总量的94.92%。它们分别是乙酸龙胆酯（60.19%）、（-）乙-酸桃金娘烯醇酯（3.87%）、α-乙酸松油酯（1.55%）、乙酰基蒈烯（1.68%）、α-芹子烯（26.07%）和（Z,E）α--法呢烯（1.56%）。结果表明乙酸龙胆酯和α-芹子烯是栽培缬草的主要成分。     

气相色谱-质谱法分析罗勒中挥发油的化学成分

利用水蒸气蒸馏法提取维吾尔药材罗勒中的挥发油成分,并用气相色谱-质谱法分析其化学成分,共鉴定出63种化学成分,占挥发性物质含量的87.49%.在罗勒挥发油中主要化学成分为a-萜品油烯(30.97%),香榧烯醇(20.57%),a-萜品油(6.87%),β-月桂烯(4.75%).δ-愈创水烯(3.19%),杜松烯(3.16%)等.     

FTIR分析脉冲电场和热处理后的大豆分离蛋白结构变化

采用自行研制的脉冲电场设备,利用傅里叶变换红外光谱(FTIR)比较研究了脉冲电场(PEF)和热处理对大豆分离蛋白(SPI)分子结构的影响.结果表明:50 kV·cn-1的脉冲场强处理引起SPI分子内和分子间氢键增强,分子中C-O-O糖苷键伸缩振动和P=O,P-O-C伸缩振动增强,且其增加值与PEF处理时间呈正相关.研究发现较短时间(1 600 μs)PEF处理导致了SPI分子结构中α-螺旋和β-折叠分别减少了5.9%和0.7%,β-转角和侧链结构分别增加了7.5%和9.6%;处理时间延长至2 400 μs,其α-螺旋和β-折叠减少量增至6.0%和5.6%.对比而言,热处理对SPI分子结构中C-O-O糖精苷键伸缩振动和P=O,P-O-C伸缩振动的影响程度较大,而对蛋白质二级结构影响程度较小:90℃热处理30 min,α-螺旋和β-折叠分别减小5.1%和6.6%,β-转角结构增加19.1%.由此可以认为PEF和热处理对SPI的影响机理是不一样的.     

原子吸收分光光度法测定石油裂解催化剂中的钠,铁和铜

本文研究了石油裂解催化剂中钠、铁和铜的测定。试样用氢氟酸和高氯酸(或硫酸)溶解后,控制溶液酸度在pH1.5-2.0范围内,分别在5589.0纳米,248.3纳米,324.8纳米波长处对钠、铁和铜进行原子吸收分光光度法测定。其相对标准偏差分别小于5%,4%和2%;回收率分别在96-101%,94-103%和97-104%之间,适合于石油裂解催化剂的分析。     

东北苍耳子挥发油化学成分分析

利用乙醚抽提东北苍耳子挥发油,GC-MS结合计算机检索对其化学成分进行分析鉴定,用色谱峰面积归一化法计算各组分的相对含量.分离出89个组分,鉴定了其中74个组分,占总挥发油量的85.63%.东北苍耳子挥发油的主要成分为3-甲基丁酸(16.421%)、3-甲基-戊酸(15.882%)、苯乙醛(11.281%)、已酸(5.051%)、糠醛(4.716%)、苯甲醇(2.358%)、苯乙醇(2.282%)等.     

基于二维相关光谱分析的纯棉与丝光棉制品鉴别分析

纯棉与丝光棉制品是日常生活中常用的两种纤维制品,但是由于二者在物理结构和化学结构上非常相似,以至于使用一些简单的方法难以准确识别一部分纯棉与丝光棉制品。提出一种使用水含量作为扰动的二维相关光谱结合机器学习方法来对二者进行鉴别的新方法。共使用从专业机构获得的200个标准样本来设计实验对新方法进行验证,其中包括100个纯棉样本与100个丝光棉样本。对每一个样本,使用水含量作为扰动,分4次改变样本水含量并采集该水含量下样本的一维光谱,其中4次的水含量分别为20.20%,14.52%,7.77%与0%。根据四条不同的一维构造每一个样本的动态光谱,再通过二维相关算法来计算其同步二维相关光谱,从该同步二维相关光谱中使用移动窗口技术提取三组不同的分类特征,每组特征分别对应一个设计好的支持向量机(SVM)分类器。之后本文提出一种基于信息熵的多分类器融合方法,根据权值不同,将三个分类器融合为一个具有更优效果的强分类器。为了验证方法的准确性与有效性,设计了严谨的实验对方法进行验证。实验首先按照传统的从一维光谱中提取特征的方法对纯棉与丝光棉样本进行鉴别,使用两种样本各50个来进行分类模型建立,剩余的进行模型验证,分类效果最高只有76%。但是基于从二维相关光谱中提取的三组特征设计的三个支持向量机(SVM)分类器的准确率分别可以达到88%,90%,88%,最后根据提出的基于信息熵的多分类器信息融合方法将三个分类器进行融合同一可以得到92%的分类准确率,比三个基础分类器准确率都有提升。与从一维光谱中提取特征并设计分类器进行分别鉴别相比,从二维相关光谱中提取特征设计多个分类器并使用基于信息熵的多分类器信息融合方法进行分类鉴别具有更高的分类准确率。二维相关光谱将光谱信息扩展到更高的维度,将一维光谱中隐藏的折叠峰进行展开,因此具有更高的分类准确率。提出的方法是一种快速准确鉴别纯棉与丝光棉制品的新方法。     

应用可见/近红外光谱进行纺织纤维鉴别的研究

为了实现纤维种类的快速鉴别,选用了棉、麻、毛、丝、天丝5种纤维,提出了一种用近红外光谱技术快速无损鉴别纤维品种的新方法。应用可见/近红外光谱漫反射技术测定各种纤维的光谱曲线,用主成分分析方法(PCA)对光谱数据进行模式特征分析,根据主成分的累积贡献率选用前6个主成分数进行建模和预测,通过建立最小二乘支持向量机模型(LS-SVM)对主成分分析模型进行优化,将前6个主成分作为最小二乘支持向量机的输入变量,建立PCA-LS-SVM模式识别模型,实现类别预测的同时也完成了数学建模与优化分析工作。5个品种的纤维训练集样本200个用于PCA-LS-SVM的模型的建立,对其余预测集样本50个进行验证,结果能准确的区分预测集的5种纤维。并提出主成分分析结合最小二乘支持向量机的光谱数据分析方法具有很好的分类和鉴别作用,为纤维品种快速鉴别提供了一种新方法,为维护消费者权益,保证纺织品质量,实现纺织原料及其制品的合理化生产与交易具有重要的意义。     

In situ surface modification of natural fiber by conducting polyaniline

Newly modified biofibers made up of kenaf fibers (KF) and conducting polyaniline (PANI) were successfully prepared via in situ polymerization. Several characterization methods were done to elucidate the interaction between the KF surfaces and the in situ polymerized PANI. The PANI coated KF (KF/PANI) achieved new electronic properties, without sacrificing its mechanical properties and natural fiber characteristic. Initial mercerization on the KF yielded better PANI coated fibers compared to the untreated KF. Fiber bundle tensile test on the untreated KF/PANI revealed a drop in the unit break of about 48% compared to the untreated neat KF. Meanwhile, the mercerized KF/PANI showed reduction of about 17% compared to the uncoated mercerized KF. The mercerized KF/PANI exhibits polaronic transitions, existence of favorable IR peaks and Raman scattering, enhanced DC conductivity, and better morphological characteristic as a result of the in situ PANI coating. Such electronically modified natural fibers could be suitable as green conducting fillers in composites to replace other synthetic fibers.     

Photoluminescence study of the surface modified and MEH-PPV coated cotton fibers

In this paper, we report a study on the photoluminescence properties of pure cotton fibers from chemically surface and morphology modified and coated with MEH-PPV polymer samples by dip-coating method. The treated and coated fibers surfaces were characterized using scanning electron microscopy (SEM), luminescence and FT-IR spectroscopy. The SEM photos showed that cotton fiber surface was covered by a layer of MEH-PPV with the thickness around 1 μm. The effects on the crystalline structure and photoluminescence (PL) were studied as a function of the alkali modification conditions. It was found that the blue light intensity of the mercerized and bleached specimen is approximately two orders higher than the scoured one. The performance of fibers with MEH-PPV polymer as a coating component was investigated and an excellent white-light emission which consists of blue-, green-, and red-light-emitting bands was demonstrated.     

Second Harmonic Generation Measurements for Biomacromolecules: Celluloses

The molecular chain orientation of mercerized cellulose II was examined by optical second harmonic generation (SHG) measurements. The SHG intensities of several kinds of mercerized cellulose II were found to be much larger than those expected for a structural model with an antiparallel molecular chain orientation as proposed by X-ray studies. This result suggests that the orientation of mercerized cellulose II is parallel as suggested by molecular dynamics simulation. © 2004 The Optical Society of Japan     

天然彩棉与普通白棉中微量元素的比较研究

建立了微波消解电感耦合等离子体发射光谱法测定棉花中微量元素的方法,并用该法分别测定了天然彩棉和普通白棉中Ca,μg,Fe,Cu,Ba,Zn,Al,Sr,Mn和Si等元素的含量。该法检出限为0.9～21 μg·L-1,加标回收率为93%～111%,RSD<4.0%(n=5);研究结果表明天然彩棉中棕色彩棉和绿色彩棉中Ca,Cu,Zn,Al,Fe,Sr和Si等元素含量要明显高于普通白棉。文章的研究结果可为彩棉的显色原理研究以及真假彩棉的鉴定提供一定的科学依据。     

Blending effect of methanol on the formation of polycyclic aromatic hydrocarbons in the oxidation of toluene

Methanol has been considered as a potential renewable liquid fuel and blending it with gasoline and diesel is an effective way to reduce greenhouse gas emissions from the transport sector. To understand the mixing effect of methanol on the formation of polycyclic aromatic hydrocarbons (PAHs) and oxygenated PAHs (OPAHs), the fuel-rich oxidation of toluene with and without methanol was studied using a flow reactor at atmospheric pressure, temperatures from 1050 to 1350 K, equivalence ratio of 9.0, and residence time of 1.2 s. The blending ratio of methanol was varied as 0% and 50% on a molar basis. Gas chromatograph mass spectrometer was employed to identify and quantify PAHs and OPAHs in gaseous products. A kinetic model on PAH growth up to five ring structures was used to investigate the blending effect on PAH and OPAH formation. Both experiment and modeling showed that PAH and OPAH production at lower temperatures was unexpectedly promoted in toluene/methanol oxidation compared with toluene oxidation, while their production in toluene oxidation was identical with or larger than that in toluene/methanol oxidation at elevated temperatures. In methanol oxidation, no PAHs were produced under the current experimental conditions. Kinetic analysis indicated that high methanol reactivity produced several radicals, such as OH, H, and HO₂, which promoted toluene reactivity at lower temperatures, resulting in the enlargement of PAH and OPAH formation in toluene/methanol oxidation compared to neat toluene oxidation. When the temperature was increased, the effect of methanol blending was diminished based on the kinetic analysis. These results suggest that oxygenated fuels do not necessarily reduce PAH production, but promote it under some conditions.     

A DNS study on temporally evolving jet flames of pulverized coal/biomass co-firing with different blending ratios

Biomass co-firing within the existing pulverized coal boiler is thought as a practical near-term way of biomass utilization, while its detailed combustion characteristics and pollutant formation have not yet been fully understood. In the present study, we report a Carrier-phase Direct Numerical Simulation study coupled with detailed mechanism to provide a deep insight into the coal/biomass co-firing (CBCF) jet flames under different blending ratios. It is found that compared with the pure coal flame, the CBCF could (i) prompt the volatiles ignition, produce higher H₂O and similar CO₂ mass fractions at blending ratios of 20% and 40%, and obviously reduce the gas temperature and CO₂ mass fraction at the blending ratio of 50%; (ii) prompt the coal devolatilization and char burnout at blending ratios of 20% and 40%, while the char burnout is reduced when blending ratio is 50% due to the local enrichment of large particles and lack of oxygen; (iii) reduce the thermal, prompt, NNH and N₂O-intermediate routes of NO formation, but show limited effect on the NO-reburning route of NO destruction, therefore, resulting in an obvious NO reduction.     

Preparation of Chitosan/Polyvinyl Alcohol Electrospinning Nano-Membranes Using the Green Solvent,Plasma Acid

Abstract

In this paper, a green solvent for chitosan, plasma acid, was made and chitosan/plasma-acid solutions were prepared. An environmentally friendly chitosan/polyvinyl alcohol (PVA) nano-membrane was prepared via electrospinning due to the difficulty of electrospinning of pure chitosan/plasma-acid solutions. Two blending methods of chitosan with PVA were investigated. One way was to mix a chitosan/plasma-acid solution (1%) and a PVA/water solution (10%) with the volume ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3 and 8:2, respectively. The results showed that fibrous nano-membranes could start to be formed at a chitosan/PVA mixing ratio of 7:3 up to the ratio of 2:8 with increasing PVA. The average fiber diameters increased with increased adding of PVA, ranging from 74.7?nm for the 7:3 ratio to 280.7?nm for the 2:8 ratio. The other way to prepare the chitosan/PVA solutions was to put PVA and chitosan powders into the plasma acid together. Fibrous nano-membranes could also be formed at 6% PVA and 10% PVA solution, both with 1% chitosan compositions. The average diameters of the resulting nano-fibers were 144.67?nm and 300.7?nm, respectively. The Fourier transform infrared (FTIR) spectroscopy results showed that the chitosan was bonded to the PVA by hydrogen bonds in the nano-membranes (6% PVA, 1% chitosan). It is noted that both of the two blending methods permitted obtaining chitosan/PVA nano-membranes. As indicated, the PVA in the solution had a large effect on the diameters of the nano-fibers. The first method permitted obtaining nano-fibers with smaller diameter. The maximum concentration of chitosan in the solution was 0.7% (7:3 ratio). The second method was simpler and permitted increasing the chitosan concentration in the solution to 1% for both the 6% and 10% concentrations of PVA.     

棉花冠层水分含量估算的高光谱指数研究

适宜的光谱指数对于地表参数高光谱诊断模型的估算精度具有决定性作用。通过不同棉花冠层水分含量表征参数冠层等效水厚度EWT_canopy, 植株含水量VWC及其对应的光谱数据分析,构建350～2 500 nm范围内所有波段两两组合的比值指数RVI和归一化指数NDVI,分析水分含量表征参数与所有指数之间的相关关系,筛选最大相关系数对应的指数作为最佳水分指数,利用新指数构建水分含量表征参数的估算模型,并与已知的各种水分指数估算精度进行比较。结果表明：新建比值指数R_{1 475}/R_{1 424}及其归一化指数(R_{1 475}-R_{1 424})/(R_{1 475}+R_{1 424})对EWT_canopy的估算效果最佳,由其得到的估算值与实测值之间的相关系数r值达到0.849;已知指数(R₈₃₅-R_{1 650})/(R₈₃₅+R_{1 650})对VWC的估算效果最佳,由其得到估算值与实测值之间的相关系数r值为0.805。