顶空和固相微萃取测定苹果芳香物质的比较

采用自动化静态顶空和固相微萃取两种样品前处理方式对苹果样品进行萃取分析,结合气相色谱质谱联用仪对苹果酯类物质进行分离检测,经计算机谱库(NIST08)检索分析结果显示,静态顶空共分离鉴定出33种酯类香气成分,固相微萃取共分离鉴定出种29种酯类香气成分,两种方法共同检出的有23种物质,其中丁酸乙酯、2-甲基-丁酸乙酯、乙酸丁酯、2-甲基乙酸丁酯等15种物质相对含量较高,分别占总峰面积的78.38%和68.71%。固相微萃取前处理方式成本更节约,基本上反映了苹果酯类香气特征物质,自动化静态顶空检测出了酯类物质成分较多,自动化程度更高,更精确地反映了苹果酯类香气特征物质。     

顶空固相微萃取GC／MS分析水果香气成分

采用顶空固相微萃取气质联用的方法，对苹果、桔子、香蕉、南果梨的香气成分进行分析，从苹果中鉴定出10种香气成分，从桔子中鉴定出28种香气成分，从香蕉中鉴定出23种香气成分，从南果梨中鉴定出28种香气成分．     

不同陈酿时间苹果白兰地主要香气成分变化分析

分析苹果白兰地橡木桶陈酿过程中挥发性香气成分的变化,采用液液萃取和气相色谱-质谱联用技术对不同陈酿时间的苹果白兰地中风味物质进行测定,并就风味物质进行聚类分析。结果表明,陈酿过程中苹果白兰地共鉴定出90种化合物,其中酯类物质43种,醇类物质32种,酸类物质15种。随着陈酿时间的延长,苹果白兰地共同酯类及酸类香气物质的种类数量和总含量呈现增加的趋势,共同醇类香气物质总含量呈现减少的趋势；而酸类香气成分的种类数量呈现先增后减的趋势。陈酿过程中,苹果白兰地中的香气成分发生着生成、更替、消失的动态变化。聚类分析结果表明,整个陈酿过程挥发性物质随变化规律聚集为3类,不同大类的苹果白兰地呈现出不尽相同的风味特征。     

野菊花中挥发油及氨基酸成分分析

采用水蒸汽蒸馏法从野菊花中提取挥发油,并用GC—MS对其化学成分进行分析测定．在最佳分析条件下,共分离出200余个峰,鉴定其中75个成分,用归一化法测定其相对含量,占挥发油总量的99．8％,其中单萜类45种,倍半萜13种;采用高效液相色谱法对野菊花头状花序的氨基酸种类及其含量进行了分析,共鉴定出16种氨基酸,其中脯氨酸含量最高．     

忍冬藤挥发油化学成分GC/MS分析

使用水蒸气蒸馏法提取忍冬藤中的挥发油,利用气相色谱-质谱联用技术对忍冬藤化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量.分析结果表明,共分离出31种组分,鉴定了其中的15个组分,占挥发油组分总量的48.39%.     

黑云香挥发油化学成分GC/MS分析

采用水蒸气蒸馏法提取黑云香中的挥发油,利用气相色谱—质谱联用技术对黑云香挥发油化学成分进行分离鉴定,采用色谱峰面积归一化法确定各成分的相对含量.分析结果表明,共分离出50种组分,鉴定了其中的22个组分,占挥发油组分总量的69.24%.     

采用SPME-GC／MS联用技术对贵定鸟王茶香气成分的测定分析

采用固相微萃取法提取贵定云雾鸟王茶和福鼎茶,经GC／MS分析,共分离鉴定出37种挥发性成分,其中鸟王茶含有29个组分、福鼎茶23个组分。相同产区的茶叶香气物质构成种类基本一致,但特征成分不同芳樟醇等是鸟王茶的特征香气成分,对构成其特征风味成分具有重要的作用。     

香辛料调味品香气成分的GC/MS分析

利用GC/MS联用对香辛料调味品的香气成分进行分离分析,共分离鉴定出48种香气成分,其相对含量较高的是烯类,占42.49%;其次是酯类,占17.36%;含量最少的是苯类,占0.65%     

迷迭香挥发油成分分析

采用水蒸气蒸馏法提取迷迭香中的挥发油,利用GC—MS联用技术进行分析,对油水分离得到的直接精油和用石油醚对水相进行萃取得到的萃取精油分别进行检测,结果显示：直接精油共分离出42个峰,其中鉴定了41种化学成分,占直接精油总量的99．54％;萃取精油共分离出37个峰,其中鉴定了33种化学成分,占萃取精油总量的91．82％;2种精油成分部分相同,相同成分占精油总量的70．00％;共鉴定了57种化学成分,占精油总量的98．57％．     

GC-MS法测定不同遮光处理下梅鹿辄葡萄发酵醪成分的变化

文章采用不同遮光率的遮阳网对宁夏贺兰山东麓酿酒葡萄"梅鹿辄"进行遮阳处理,运用顶空固相微萃取技术提取葡萄酒香气成分,用气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS)进行分离测定,结合计算机检索技术对分离化合物进行鉴定,应用TIC峰面积归一法测定各成分的相对质量分数,分析研究了宁夏贺兰山东麓地区"梅鹿辄"葡萄在不同光照条件下的化学成分。分析结果表明:在自然光照(对照组)、40%遮阳、50%遮阳及60%遮阳处理后的葡萄酒样品中,分别分离出62、47、58和49个峰,鉴定出50、46、52和51个香气化学成分,共占其色谱流出组分总量的97.29%、95.08%、104.25%和95.53%;梅鹿辄葡萄酒中的香气成分主要为醇类、酯类、酸类、烃类,不同光照强度处理的葡萄酒中香气成分质量分数差别明显,因此光照强度对"梅鹿辄"葡萄的香气成分与比例及感官质量有重要影响。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the