DUO-ICP-AES测定精对苯二甲酸中的钴、铬、铁、锰、钼、镍、钛

采用DUO-ICP-AES同时测定精对苯二甲酸中钴、铬、铁、锰、钼、镍、钛,并对仪器的分析线选择、背景校正、入射功率、雾化器压力、辅助气流量、冷却气流量、蠕动泵转速的影响及共存元素的干扰、硝酸铯灰化助剂等因素进行了详细的研究。方法的检测限:钴0.0097 mg/L;铬0.0021 mg/L;铁0.0078 mg/L;锰0.0012 mg/L;钼0.0027 mg/L;镍0.016 mg/L;钛0.0027 mg/L,回收率和精密度分别为93.0%～99.5%和0.37%～3.2%。该方法快速简便,具有良好的精密度和准确度,适用于进出口精对苯二甲酸的日常检验。     

ICP—AES测定石英砂中的铁、铝、钙、钛、硼、磷

本文阐述了用ICP—AES法同时测定石英砂中的Fe、Al、Ca、Ti、B、P,试样用HF和H2SO4加热分解,HCl溶解盐类。试样的处理只需一次便可做多元素的分析。测定结果准确、快速,相对偏差小,在操作上更易掌握。     

染发剂中铁、铜、铬、镉、铅、镍和钴等重金属含量测定

建立了微波消解前处理,电感耦合等离子发射光谱(ICP-AES)测定染发剂中铁、铜、铬、镉、铅、镍和钴等重金属含量的方法。该方法各元素检出限均为0.05 mg/kg,线性范围0～500 ng/mL,加标回收率86.8%～108.0%,相对标准偏差为0.98%～5.54%。该方法简便、灵敏,结果稳定准确,可以用于染发剂中重金属含量的测定。     

对羧基苯甲醛、对甲基苯甲酸、苯甲酸、对苯二甲酸和间苯二甲酸在N,N-二甲基甲酰胺中的溶解度

采用激光监视技术由合成法实验测定了对羧基苯甲醛、对甲基苯甲酸、苯甲酸、对苯二甲酸和间苯二甲酸在N,N－二甲基甲酰胺中的溶解度。实验数据用多项式方程进行关联,计算的溶解度与实验值符合良好。     

ICP-AES分析低合金钢中的Mn、Mo、V、Ni、Al、Cu、Cr元素

用等离子发射光谱法测定低合金钢中的Mn、Mo、V、Ni、Al、Cu、Cr元素,试样用HNO3和HCl在加热条件下分解,经过系列试验,选择仪器的工作条件,进行测定,建立了一套分析方法,经对照分析,分析结果令人满意。本方法快速准确,精密度良好,完全可以满足生产需要。     

ICP-OES测定大量元素水溶肥料中锌、镁、铜、铁、锰、钼、硼含量

采用ICP-OES对大量元素水溶肥料中微量元素锌、镁、铜、铁、锰、钼、硼进行分析,研究确定了最佳分析条件。加标回收率为96.94%～106.2%,RSD为0.50%～1.40%,检出限为0.001 8～0.218 0 mg/L,方法简便、快速、准确。     

Dispirations,disclinations, dislocations,and chain twist in polyethylene crystals

It is proposed that the twist in polyethylene chains that can result from crystallization and subsequent deformation aggregates at boundaries and becomes a template for further reorganization that results in the long period observed in polyethylene fibres. The observed lower density at the boundaries requires the transport of free volume to the twist boundaries. Dispirations, disclinations and dislocations are crystallographic defects that are involved in the necessary transport mechanism. Twist and bend, derived from the Eulerian angles which are computed from the sets of chain internal coordinates, relate the orientation of different segments of a chain. Twist and bend are useful for the characterization of both crystallographic defects and arbitrary conformations of polymer chains. Defects, along with folds, chain ends, and ordinary edge and screw dislocations provide a basis for interpretation of structure-property relationships in solid polyethylene.     

Lactones in butter,butteroil, and margarine

The γ- and Δ-lactones of butter, butteroil, and margarine samples were determined by a recently developed extraction and chromatographic method. A chromatographic column is made of three layers consisting of 6 g aluminum oxide upon which is placed 35 g sodium sulfate and then a fat-Celite mixture obtained by grinding 10 g sample with 35 g Celite 545. The column was eluted with acetonitrile, and the extract was concentrated and lactones determined by gas chromatography. γ-Dodecalactone, Δ-decalactone, Δ-dodecalactone, and Δ-tetradecalactone were recovered quantitatively. Freshly made butter had only 7 ppm of these lactones, whereas commercial samples ranged from 12–30 ppm. Two of eight commercial margarine samples had as much as 10 ppm of Δ-decalactone and Δ-dodecalactone. Comparison of unheated butteroil with butteroil heated at various temperatures showed a correlation of lactone content with time and temperature of heating. Butteroil heated at 65 or 100 C showed increasing levels of lactones up to 8 hr, whereas butteroil heated at 145 or 125 C showed a maximum production at ca. 2 and 4 hr, respectively.     

Soy grits,flour, concentrates,and isolates in meat products

Because of changing attitudes of consumers, processors, and regulatory agencies, soy protein products are being used at an increasing rate in various processed meat systems. The use of basic soy protein products in several meat systems is examined and guidelines are presented to optimize their use. Soy products as a supplemental ingredient in various meat systems can contribute nutrition, flavor, and valuable functional properties. As the price of meats continues to rise, and consumer interest in nutrition continues to increase, their demands will prompt governmental agencies to reconsider present meat regulations.     

ICP—AES法测定镍铁中Si、Co、Cu、P、Mn、Cr

研究了用ICP—AES法测定镍铁中Si、Co、Cu、P、Mn、Cr元素含量的分析方法。分析了镍基和铁基效应对某些元素强度影响情况,采用基体匹配法消除镍基和铁基的干扰效应。采用信倍比和净强度为仪器测量的选择条件,用多元素混合标准溶液绘制工作曲线。测出镍铁中的Si、Co、Cu、P、Mn、Cr元素分析方法检出限。此方法有较高准确度和精密度。     

Breaking, making, and twisting of chemical bonds in gas, liquid, and nanocavities

In this Account, we recount on our studies of 1'-hydroxy-2'-acetonaphthone (HAN, a proton transfer prototype molecule) in gas, solutions, and nanocavities. The internal H-bond photoreaction in HAN leads to a keto type structure, and following its formation, an internal twisting motion gives birth to keto rotamers. Theory, temperature, and solvent effects on its photodynamics show the involvement of efficient radiationless processes in both keto structures. When HAN is caged in a cyclodextrin nanocavity, the spectroscopy, photodynamics, and issues of twisting motion are strongly affected and could be tuned: a behavior relevant to those of many chemical and biological systems.     

电感耦合等离子体原子发射光谱法同时测定金属饰品中铅、镉、铬、汞、锑、砷、硒、钡、镍含量

采用电感耦合等离子体原子发射光谱法同时测定金属饰品中铅、镉、铬、汞、锑、砷、硒、钡、镍的含量.用体积比为3∶1的浓硝酸和浓盐酸微波溶解样品,研究了样品的消解方法、消解介质、分析谱线及工作参数等对检测结果的影响.方法的检测限(mg/L):铅0.06、镉0.009、铬0.002、汞0.04、砷0.02、硒0.01、钡0.0...     

Dissolution in Ceramic Systems: 11, Dissolution of Aluminu, Mullite, Anorthite, and Silica in a Calcium-Aluminum-Silicate Slag

Experimental measurements have been made on the rate of dissolution of sapphire, dense poly-crystalline alumina, mullite, fused silica, and anorthite in a 20A1₂O₃-4OCaO-40SiO₂ slag at 1350° to 1500° C under conditions of free and forced convection. Dissolution rates and their temperature dependence were found to be controlled by transport within the liquid boundary layer. At low temperatures alumina is by far the most corrosion resistant; at higher temperatures differences between the refractories tested are less pronounced.     

Studies in Germanium Oxide Systems: IV, Phase Equilibria in the System K,O-GeO,

Phase relations in the binary system K₂O-GeO₂ were determined by conventional quenching techniques. Three compounds, K₂O.2GeO₂, 3K₂O.11GeO₂, and K₂O.7GeO₂, exist in the composition range 65 to 100% GeOn. The compound 3K₂O.1lGeO₂ melts congruently at 1055°C, whereas K₂O.2GeO₂ and K₂O.7GeO₂ melt incongruently at 761° and 950°C, respectively. Thermal expansion data for the crystalline compounds are presented. The structure of potassium germanate glasses is discussed.     

ICP-OES法测定Ti80钛合金中铝铌锆钼铁硅

采用ICP-OES法测定了Ti80钛合金中铝、铌、锆、钼、铁、硅元素的含量。用H2O-HCl-HF-HNO3(5+5+1+1)对样品进行溶解;确定了各元素测定谱线为Al 394.401nm、Nb 269.706nm、Zr 339.197nm、Mo202.031nm、Fe 259.939nm、Si 288.158nm;建立了校准曲线,各元素线性相关系数均在0.999以上;测定了方法检出限,各元素检出限均小于0.003%;测定结果的RSD/%在0.79%~3.42%之间(n=7),加标回收率在97.0%~104.0%之间。     

ICP-AES测定结瘤物中Ti、Mg、Al、Ca、Si、Mn和Fe

研究ICP-AES同时测定结瘤物中Ti、Mg、Al、Ca、Si、Mn和Fe的分析条件。结瘤物试样以过氧化钠为熔剂,于镍坩埚内进行快速熔融,熔块以热水浸取,HCl溶解试样,制成母液。采用标准溶液制定校准曲线和内标法,ICP光谱仪直接测量试样溶液中Ti、Mg、Al、Ca、Si、Mn和Fe含量。通过选取合适的工作参数与观测方式,采用基体匹配法测定了合成样及结瘤物样品,合成样品的回收率在98%~104%,实际样品独立测量8次的相对标准偏差均小于2.0%(RSD<2.0%,n=8),本方法适用于生产检验。     

2013年全球主要农药公司的市场、主要品种及销售额和科研开发费用

介绍了2013年世界主要农药公司的农药销售额、市场、主要品种及销售额和用于新农药研发的费用等。     

Fatty Acids,Tocopherols, Tocotrienols,Phytosterols, Carotenoids,and Squalene in Seed Oils of Hyptis suaveolens,Leonotis nepetifolia,and Ocimum sanctum

The oil yield and composition of fatty acids, tocopherols, tocotrienols, sterols, carotenoids, and squalene in the seeds of three species—Hyptis suaveolens, Leonotis nepetifolia, Ocimum sanctum—belonging to the Lamiaceae family, are studied. The oil yields are 12.1%, 16.1%, and 29.0% in O. sanctum, H. suaveolens, and L. nepetifolia, respectively. The unsaturated fatty acids are a predominant group (86.8–92.1%) in all three investigated plants; however, the profile for each species is unique. The main fatty acid differs as follows: H. suaveolens—linoleic acid (85.8%), L. nepetifolia—oleic acid (58.3%), and O. sanctum—α‐linolenic (48.6%). γ‐Tocopherol accounts for over 97%, 90%, and 93% of the total tocochromanol content (sum of tocopherols and tocotrienols) in H. suaveolens, L. nepetifolia, and O. sanctum, respectively. Two tocotrienol homologues, α and γ, are detected only in L. nepetifolia. β‐Sitosterol is the main detected sterol (38–59%) in all three species. High levels of campesterol (18–20%), Δ5‐stigmasterol (9–21%), and Δ5‐avenasterol (7–12%) are also detected. Squalene is detected only in O. sanctum (45.8 mg/100 g oil). The content of sterols, tocochromanols, and carotenoids in the investigated Lamiaceae plant seed oils ranges between 279.5–576.3, 54.5–66.7, and 0.3–3.1 mg/100 g oil, respectively. Practical Applications: Lamiaceae plants are of medicinal interest due to the presence of a broad spectrum of bioactive molecules. The present study demonstrates that seeds of the species H. suaveolens, L. nepetifolia, and O. sanctum are rich sources of bioactive compounds of lipophilic nature. There is limited knowledge associated with the composition of tocopherols, tocotrienols, sterols, carotenoids, and squalene. The results of the studied medicinal plants may enhance future targeted applications in various sectors.     

China's Trade for HDPE,MEG,SM,Reactive Dye,Barium Sulfate,STPP,Soda Ash,DMF and EPS in December 2009

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