玉米蒸煮香气成分的研究

结合同时蒸馏萃取法（SDE）和固相微萃取法测定五粮液酿酒用玉米的挥发性香气成分。用GC-MS以大体积进样方式分析,共检出99种组分,其中烃类18种,醛类13种,酮类15种,醇类12种,酸类7种,酯类9种,苯类13种,酚类3种,杂环类9种。含量较高的有2,4-葵二烯醛（1.116%）、苯并噻唑（2.666%）、4-乙烯基愈创木酚（2.231%）、2,3-二氢苯并呋喃（1.982%）等。并对不同品种的玉米香气成分进行了比较。     

芯片载板检查

随着电子工业向微型化、高密度和高速封装的趋势的速度发展越来越快,出现了硅芯片基板也就是芯片载板来适应这些形势。在芯片载板的生产中,质量控制尤其重要。这样,寻求一种自动检测手段作为严格质量的辅助手段就成为必需。文章就AOI(自动光学检测)、LVI(激光盲孔检查)、AVI(自动化目检)几种检查手段及其新技术的应用进行了介绍。     

Two/Infinity Norm Criteria Resolution of Manipulator Redundancy at Joint‐Acceleration Level Using Primal‐Dual Neural Network

A two/infinity norm criteria (termed bi‐criteria) weighting scheme is proposed in this paper for resolving manipulator redundancy at the joint‐acceleration level. This bi‐criteria scheme is aimed at remedying discontinuity‐points and torque‐instability problems which arise in pure infinity‐norm acceleration‐minimization schemes. By incorporating joint physical limits, the proposed bi‐criteria redundancy‐resolution scheme can finally be formulated as a quadratic program (QP) subject to equality constraint, inequality constraint and bound constraint simultaneously. As a real‐time QP solver with simple piecewise‐linear dynamics and higher computational efficiency, the primal‐dual neural network based on linear variational inequalities (LVI) is presented in this paper to solve online such a bi‐criteria weighting scheme. Computer‐simulation results based on a PMUA560 robot arm illustrate the advantages and efficacy of such a neural weighting scheme.     

绞股蓝皂苷成分的分离与鉴定

目的 提取、分离、鉴定绞股蓝皂苷主要成分。方法 利用硅胶柱色谱及反相半制备柱色谱等分离手段, 分离、纯化绞股蓝皂苷成分, 并用核磁共振波谱(1H-NMR、13C-NMR)、液相色谱离子阱飞行时间质谱(LCMS-IT-TOF)等方法鉴定化合物结构, 并对相关成分的抑癌作用进行了研究。结果 绞股蓝总提物的主要成分经分离得到2种达玛烷类皂苷, 分别为绞股蓝皂苷gypenoside XLVI和gypenoside LVI, 而且它们具有一定的抑制癌细胞增殖作用。结论 利用硅胶柱色谱和反相半制备色谱方法从绞股蓝总提物中分离得到主要的皂苷成分, 为进一步研究其抑癌有效成分提供了参考。     

Routine analysis of off-flavor compounds in water at sub-part-per-trillion level by large-volume injection GC/MS with programmable temperature vaporizing inlet

"Earthy-musty" off-flavor problem in water samples are due to organic compounds present at the sub-part-per-trillion level. Most of the developments in the analysis of tastes and odorous compounds focus on the extraction pre-concentration technique, with detection at picogram per liter level of the earthy-musty off-flavor compounds difficult to be achieved. The objective of this study is to develop a new method involving the large-volume injection (LVI) GC/MS via programmable temperature vaporizing (PTV) inlet and continuous liquid-liquid extraction, to attain analytical sensitivity equal to or better than olfactory sensitivity. Six "earthy-musty" organic compounds, 2-methylisoborneol (MIB), geosmin, 2,4,6-trichloroanisole, 2,3,6-trichloroanisole, 2,3,4-trichloroanisole and 2,4,6-tribromoanisole, were used as probes for this study. It was found that LVI via PTV could greatly improve system sensitivity towards off-flavor compound detection. Variable instrument conditions and sample preparation conditions were studied in detail. This reliable and efficient method has been optimized and validated. The method detection limit were found to be from 35 to 70 pg/L for haloanisoles, 50 pg/L for geosmin and 0.34 ng/L for MIB, with relative standard deviation of calibration curve ranging from 4.7% to 15.1% and recovery ranging from 58% to 96%. This method has been successfully applied to test off-flavor compounds in different types of water samples with satisfactory results.     

酿酒用糠壳中蒸煮气味成分的研究

采用同时蒸馏萃取法(SDE)和固相微萃取法研究了酿酒用糠壳的挥发性气味成分。用GC-MS采用大体积进样方式分析,共检出糠壳气味成分物质175种,其中,烃类14种,醛类16种,酮类13种,醇类11种,酸类4种,酯类11种,苯类30种,其他类33种,未知物43种,对比蒸前、蒸后糠壳成分的差异,为白酒中糠味异杂味的控制提供一定的参考。     

Effect of woven yarn angle on the low-velocity impact damage response of fibre woven thermoplastic composites

Fibre woven thermoplastic composites (FWTC) are widely used in aerospace and other fields because of their excellent performance. During service, FWTC structures are inevitably subjected to low-velocity impact (LVI), which can cause invisible damage and eventual failure of the material. At the moment, studies on FWTC mostly focused on the orthogonal woven yarns while there's few reports about the effect of the yarn angle changing on the woven material's LVI damage response. This study aims at the effect of yarn angle changing on the damage behaviour of FWTC. A method for preparation of nonorthogonal prepregs was proposed, by which FWTC laminates with different yarn angles (60°, 75°, and 90°) were prepared for LVI tests. The results show that the maximum impact displacement and the impact duration of the impactor decrease with the decrease of the yarn angle when the FWTC laminate is subjected to LVI, while the maximum impact force shows an increasing trend. This indicates that the smaller yarn angle causes the better load-bearing capacity of the FWTC laminate under LVI conditions, while the orthogonal FWTC laminate is more ductile. The damage morphology indicated by the impact of the FWTC laminate are matrix cracks and yarn breaks, and the damage area increases with the decrease of yarn angle, where the damage of orthogonal laminate is more serious more concentrated. The results found in this paper can provide useful guidance for engineering applications and failure analysis of FWTC.     

Analysis of non-cleaned QuEChERS extracts for the determination of pesticide residues in fruit,vegetables and cereals by gas chromatography-tandem mass spectrometry

This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg^?1 in two sets of samples: one with and one without clean-up. For both spiking levels, 80–82% of the pesticides in the non-cleaned extracts and 80–84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70–120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93–95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailed t-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of ?20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up.     

大米、糯米蒸煮香气成分的研究

采用同时蒸馏萃取法(SDE)和固相微萃取法研究了五粮液酿酒用大米和糯米的挥发性香气成分。用GCMS采用大体积进样方式分析,共检出大米香气成分物质101种,其中烃类18种,醛类14种,酮类16种,醇类10种,酸类7种,酯类8种,苯类12种,酚类5种,杂环类11种;共检出糯米香气成分物质76种,其中烃类15种,醛类9种,酮类12种,醇类9种,酸类7种,酯类3种,苯类6种,酚类7种,杂环类8种,对不同品种大米和不同品种粮食的香气成分进行了比较。     

HC08单片机LVI模块功能分析及其测试过程

LVI模块作为HC08单片机的重要组成部分,保障了单片机的可靠运行,在工业应用中发挥着重要作用。文章阐述了HC08型单片机LVI模块组成结构,作用原理及其基本应用。特别介绍了LVI的常用指令,寄存器设置。分析了LVI模块的一般测试过程,并专门针对J750测试机分析了它的测试参数。