法布里干涉近红外光谱仪定量测定大豆、玉米主要成分

采用Axsun近红外光谱仪采集40个大豆样品、46个玉米样品的近红外光谱,采用PLS算法分别建立大豆粗蛋白质、脂肪含量的定量校正模型和玉米粗蛋白质、脂肪、淀粉含量的定量校正模型。结果表明,大豆粗蛋白质、脂肪定量校正模型的模型维数分别为6、5,决定系数(R~2)分别为97.94%、93.66%,校正均方根误差(RMSEC)分别为0.40、0.36.交互验证均方根误差(RMSECV)分别为0.49、0.44,相对预测性能(RPD)分别为5.18、3.15;玉米粗蛋白质、脂肪和淀粉含量的定量校正模型的模型维数分别为4、4和6,R~2分别为90.15%、95.22%和87.81%,RMSEC分别为0.25、0.12和0.53.RMSECV分别为0.37、0.15和0.72,RPD分别为2.57、3.57和2.42。F检验表明,上述校正模型的预测值与化学值具有极显著的相关关系。研究结果表明,该仪器可以用于大豆、玉米主要成分定量现场快速测定。     

NIR法测量食品含油率的实验装置

ＮＩＲ法测量食品含油率的实验装置＊汪延祥顾伟珠阮再洪（杭州商学院杭州３１００３５）０引言衡量食品品质常要求了解其中蛋白质、脂肪、淀粉和水分等主要成分的含量。然而，快速而又准确地测定这些成分的含量是困难的。利用食品的近红外吸收光谱，测定上述成分，具有明...     

食品中亚硝酸盐现场快速定量检测系统的研制

研究了一种用于现场检测食品质量产品的“检测系统”——食品中亚硝酸盐现场快速定量检测系统,该检测系统由主机、试剂盒、校准品和操作程序等构成.对该检测系统所涉及的波长示值误差和重复性、测量线性、检测仪示值误差和重复性、稳定性等进行了系统性研究.测试结果表明,光源示值误差范围为-1.1～6.2nm,光源重复性范围为0.0～0.8nm;线性相关系数R2的范围为0.9930～～ 0.9955;校准品(40.0mg/kg)示值误差范围为0.12％～ 2.90％,重复性范围为7.15％～8.31％;标准溶液进行测定(6.0mg/L),示值误差范围为-1.92％～-0.87％,重复性范围为1.59％～～ 2.00％;检测仪稳定性为-0.001Abs/h～0.002Abs/h;并将该检测系统应用到肉制品、腌菜等样品中亚硝酸盐含量的现场快速定量测定,从取样到报出检测结果在30分钟内即可完成,与国家标准方法进行了比对,结果令人满意.     

电容式智能水分测定仪的设计

少量水分的快速、准确测定成为皮革生产过程中至关重要的环节,在研究了多种水分测定原理的基础上提出一种利用电容式传感器进行水分测定的方案,实现了一种快速的非破坏性测定方法,该方法可以广泛用于皮革、纸板等非刚性物体水分含量的检测。实验结果表明,该仪器具有测定准确度高、速度快、性价比高、操作方便的特点。     

原子荧光法同时测定水产品中砷和汞

采用微波消解样品，原子荧光法（AFS）同时测定水产品中砷和汞。研究了仪器条件、酸度、硼氢化钾浓度等对测定的影响，砷和汞的检测限为0．05μg／L和0．01μg／L；相对标准偏差为1．46％和1．51％；回收率为84.9％～112．5％和90．0％～115．0％，用该方法分析水产品，结果满意。     

用鲜奶脂肪含量快速测定仪测定牛奶中脂肪含量

脂肪和蛋白质是鲜牛奶中的主要营养成份,其含量的测定国内外一般都采用化学方法,仪器法,操作较复杂,测定时间较长,不适用于大批样品的分析。近几年来国内也有部分快速测定仪,但操作均较复杂,使用有一定的局限性。我们采用红外线技术及精密光学检测探头的快速测定仪,无需取样即可直接检测牛奶原液,突破了同类机型多年来一直未能解决的问题。下面通过常规方法的实验来验证仪器的可靠性。实验部分 1.仪器和试剂: (1)仪器:NC-A鲜牛奶中脂肪含量     

便携式快速色谱-质谱联用仪器的研制与应用

针对挥发性和半挥发性有机物的现场检测,基于快速色谱分析技术和三维离子阱质谱技术,研制了便携式快速色谱-质谱联用仪,仪器具有吸附热解吸进样和进样口直接进样两种分析模式,能实现气体、水体和固体中有机物的现场测试。本文详细描述了该仪器的主要组成结构,对该仪器进行性能测试,结果显示该仪器分析速度快（苯系物分析时间不超过2分钟）,灵敏度高（0．1ng甲苯总离子流色谱峰的峰／峰信噪比143）,便携性优（重量14kg）、性能稳定（峰面积RSD≤5％）。土壤、污染源和刑侦领域中挥发性有机物和半挥发性有机物（地西沣,沸点492℃）的现场分析结果表明,仪器具有分析速度快、进样方式多样和适用于半挥发性有机物分析等优点,能用于现场监测领域有机物快速定性定量分析。     

近红外分析仪

近红外分析是利用光谱方法快速、定量分析农产品(包括谷物、油料、饲料、烟草等,的主要成分,如蛋白质、脂肪、淀粉(糖)、纤维、水分等。本文介绍我们研制的9波长,4×4定标方程近红外分析仪的工作原理、仪器总体结构、电子学系统原理、计算机软硬件系统及测试结果。     

快速失重法测量玉米水分的研究

研究了用快速失重法测量玉米水分的方法。通过实验确定了玉米的极限失重温度，介绍了用快速失重法测量玉米水分的实例。这是一种快速自动测量玉米水分的新方法，其精度为±０．２％，测量时间为１４ｍｉｎ。     

快速检测三聚氰胺激光拉曼光谱仪问世 检测仅需半分钟 准确率达100％

三聚氰胺事件引发了人们对牛奶及食品添加剂安全的关注。中国检验检疫科学研究院2月28日宣布,该院利用激光拉曼技术,自主研发了用于现场快速检测三聚氰胺的激光拉曼光谱仪以及配套试剂。使用该仪器和配套试剂,能定量检测出液态奶中高于0．5ppm（百万分之一）三聚氰胺,准确率达100％,每个样品检测仅需半分钟。     

Investigation of the mechanism of lubrication in starch–oil composite dry film lubricants

The boundary coefficient of friction (COF) of starch–oil composite dry film lubricants was investigated as a function of starch type (waxy vs. normal purified food grade corn starch), oil chemistry (hexadecane vs. oleic acid and various vegetable oils), and starch‐to‐oil ratio. Based on the results, a mechanism of starch–oil interaction in these composites was proposed. According to the proposed mechanism: (a) the oil in the composite is distributed between the bulk and the surface of the starch; and (b) the fraction of the oil trapped in the bulk and that adsorbed on the surface are related to each other by an equilibrium constant, and are functions of the total oil concentration in the composite. In line with the proposed mechanism, an adsorption model was used to quantify the free energy of adsorption (ΔG_ads) of the polar oils onto the starch surface. The analysis gave ΔG_ads values that were higher than those reported for the adsorption of the same polar oils onto steel surfaces. This result is consistent with the effect of the relative surface energies of steel and starch on the adsorption of polar oils. The adsorption property of the non‐polar hexadecane relative to the polar oils was estimated by comparing their interfacial tensions with starch. The result showed a higher interfacial tension for hexadecane–starch than that for the polar oil–starch composites. This result predicts a relatively poorer compatibility with, and, hence, poorer adsorption of hexadecane onto starch leading to higher COF, as was observed in the friction measurements. Published in 2006 by John Wiley & Sons, Ltd.     

Microstructural changes in zein proteins during extrusion

Changes in proteins during extrusion may influence the texture of ready-to-eat (RTE) corn-based extruded foods. This study focused on microstructural changes and dispersal patterns of corn storage proteins, zeins, that occur during extrusion processing. Model systems were used that consisted of two types of corn protein: commercial zein and corn gluten meal (CGM), combined with corn starch. Commercial zein is not encased in protein bodies, whereas CGM is comprised of zeins encapsulated in protein bodies. Mixtures were extruded under conditions that resulted in different specific mechanical energy (SME). The microstructure of the resulting extrudates was analyzed using transmission electron microscopy (TEM) with immunogold labeling of the α-zein storage protein. The micrographs showed that the greatest zein dispersal occurred in CGM/starch extrudates, especially under high SME conditions. The micrographs also showed that, at both mild and harsh extrusion conditions, commercial zein/starch extrudates contained large protein aggregates. Under mild extrusion conditions, protein bodies in the CGM/starch extrudates partially retained their spherical shapes, but during harsher processing, protein bodies were disrupted and dispersed zein appeared to form fibrils. Such protein fibrils may influence texture and/or quality of extruded corn-based snacks and breakfast foods.     

基于PSO-ELM的液压油性能衰退预测及分析

提出基于粒子群优化（Particle Swarm Optimization,PSO）的极限学习机（Extreme Learning Machine,ELM）的液压油性能衰退预测方法。以L-HM46抗磨液压油为研究对象,设计液压油性能衰退实验,检测油液的黏度、张角、水分含量、衰退度。基于提出的液压油性能衰退预测方法,利用遍历搜索和PSO算法分别对ELM的外部、内部参数进行优化选取,从而建立最优的性能衰退预测模型。将油液的黏度、张角、水分含量作为模型输入特征向量,衰退度作为模型输出,采用PSO-ELM性能衰退预测模型对液压油性能进行仿真分析。结果表明：PSO-ELM算法计算结果与实验数据吻合较好;PSO-ELM算法预测精度达到了98.47%,高于ELM算法的预测精度,表明PSO-ELM算法能更准确地预测液压油的衰退情况,为确定换油时机提供参考。     

Friction and Wear Phenomena of Vegetable Oil–Based Lubricants with Additives at Severe Sliding Wear Conditions

The tribological responses of palm oil and soybean oil, combined with two commercial antiwear additives (zinc dialkyl dithiophosphate and boron compound), were investigated at a lubricant temperature of 100°C and under severe contact conditions in a reciprocating sliding contact. The friction coefficient of palm oil with zinc dialkyl dithiophosphate was closest to the commercial mineral engine oil, with a 2% difference. The soybean oil with zinc dialkyl dithiophosphate produced a 57% improvement in wear resistance compared to its pure oil state. The existence of boron nitride in vegetable oils was only responsive in reduction of wear rather than friction. The response of commercial antiwear additives with vegetable oils showed a potential for the future improvement in the performance of vegetable oils.     

Tribological Properties of Vegetable Oils Modified by Reaction with Butanethiol

Corn, canola, and castor-lauric estolide oils were chemically modified by photochemical direct reaction of butanethiol with the double bonds on the hydrocarbon chains. The effect of chemical modifications on viscosity, viscosity index (VI), pour point (PP), cloud point (CP), oxidation stability (RPVOT), 4-ball anti-wear (AW), and extreme pressure (EP) were investigated. The sulfide modified (SM) corn and canola oils showed increased viscosity, increased RPVOT time (more than one order of magnitude), reduced PP (9?C18 °C), and reduced VI. The SM estolide displayed similar trends in VI and RPVOT but showed no change in viscosity or cold flow. The SM oils, along with commercial mono- and polysulfide additives were also investigated as additives, at 0.6% (w/w) S concentration, in corn and polyalphaolefin (PAO) base fluids. In both fluids, the additives resulted in minor changes of PP, CP, coefficient of friction, wear scar diameter (WSD), and weld point (WP). Only the commercial polysulfide EP additive displayed large WP increases in the fluids. The additives resulted in no change of oxidation stability of corn oil, but displayed big improvement in the oxidation stability of PAO (8 to 16-fold increase in RPVOT time). The difference in the effect of the additives on the oxidation stability of PAO versus corn oil was attributed to the difference in the reactive hydrogen contents in the two base fluids relative to those in the additives. An empirical equation, for correlating change in RPVOT time with change in bond dissociation energy of reactive protons before and after chemical modification, is proposed.     

Presentation of a test rig with its experimental procedure and uncertainty analysis of measurements for batch type fluidized bed drying of corn and unshelled pistachio nut

This paper gives the hardware and software of a test rig with its experimental procedure, methodology and uncertainty analyses of measurements for batch type fluidized bed drying of corn and unshelled pistachio nut. The test rig is designed, constructed and operated for the analyses of drying performance of corn and unshelled pistachio nut in a batch type fluidized bed drying. The details of the test rig, the experimental procedure, the uncertainty analyses and the investigation of the effects of drying parameters on drying performance are the major scope of the paper. The accuracy of the experimental study herein is based on velocity, pressure, temperature and moisture measurements. Therefore it is vital and sensitive phenomenon for the determination of the uncertainties of the measurements before the current study as is the case with all other studies. The test rig is designed and constructed in accordance with literature review which is mentioned briefly in this paper. The basic terminology which is used in this study is also introduced herein. The overall uncertainties of velocity, pressure, temperature and moisture measurements are performed and found as 1.7%, 1.3%, 0.3% and 1.6%, respectively. Some pioneering studies related on conventional batch type fluidized bed dryers operated under atmospheric pressure are also tabulated as an original contribution to literature. Moreover, the effects of the particle mass, drying air temperature and drying air velocity on drying performance of the batch type fluidized bed dryer which is assisted with a conventional electrical heater unit are outlined without going into details in thermo- and fluid-dynamics of drying process.     

核电循泵齿轮箱在线油液监测系统研究

以核电厂CRF循泵齿轮箱系统为对象,对油液在线监测系统的监测结果及可靠性开展分析。基于工况环境和特点,选择监测指标并设计相应的监测系统进行现场部署。通过对齿轮箱的在用油指标监测,系统分析水分、黏度、温度、污染度及各指标间的相关性,并与离线检测的数据进行对比分析。结果表明：设计的CRF循泵油液在线监测系统能真实反映油液各指标的实时状态,各指标变化趋势符合油液实际规律,与离线检测数据偏差在正常范围内。设计的油液在线监测系统在核电循泵中的应用可靠性高,能以此为依据进行故障预警及诊断。     

Tribological Performance of Engine Oil Blended with Various Diesel Fuels

In this study, petrodiesel (D100) and different concentrations of commercial biodiesels (B100, B50, B5) were blended with a commercial engine oil at a fixed volume ratio of 1:9 to investigate the tribological effect of the biodiesels on the antiwear performance of the engine oil. The antiwear performance of the blended oils was evaluated using a Plint TE77 reciprocating ball-on-flat tribometer at room temperature and 150°C. Results show that the antiwear performance of the engine oil blended with petrodiesel is worse than that of the other blended oils with biodiesels at both temperatures. At room temperature, the physical adsorption and local hydrodynamic effects of the blended oils dominate the tribological behavior; at 150°C, the biodiesel seems to promote the growth of a reaction film with the antiwear additives in engine oil and enhance the growth rate of chemical films. However, an excess concentration of biodiesels causes tribochemical wear, thus reducing antiwear performance.     

液压设备的润滑磨损故障及监测诊断

本文分析了液压油的性能及污染对液压设备润滑磨损故障的影响，简述了基于油液监测技术的设备视情维修的基本原理和方法，并介绍了广州机械科学研究院在此方面的工作实践。     

Effects of Chlorinated Paraffin and ZDDP Concentrations on Boundary Lubrication Properties of Mineral and Soybean Oils

Concentration effects of chlorinated paraffin and zinc di-ethylhexyl dithio phosphate on boundary lubrication properties were tested in vegetable and mineral base stocks. Solvent refined low sulfur paraffinic mineral oil (150 N oil) and conventional food grade soybean oil (soy oil) with EP additive concentration of 0–20% (w/w) were used in ASTM D2783 four-ball extreme pressure (4-ball EP) and Twist Compression Tribotests (TCT). Weld points in 4-ball EP and times to failure in TCT at 200 MPa showed that 150 N oil needed more than double treat levels of EP additives to achieve similar boundary lubrication performance as their 5% blends in soy oil. Also, incorporation of 20% soy oil into 150 N oil-based EP additive blends improved the performance to nearly the same level as soy oil only blends of corresponding additives. Boundary lubricity of some soy oil samples was similar to that of a commercial straight oil chlorinated metal forming lubricant. Several suggestions are provided to explain such pronounced influence of the base stock type on EP additive response. The findings suggest that soy oil and other farm-based oils may provide strategies for formulating cost effective industrial fluids and other lubricants.