气态元素汞校准的一致性光学评定检测实验研究

利用低压汞灯作为光源,结合单色仪,对汞渗透管法和汞饱和蒸气法气态元素汞校准进行一致性光学评定检测研究。在汞渗透管实验中,吸收度面积值与理论浓度的皮尔逊相关系数为0.996 8,拟合优度为0.993 6,说明两组数据相关性较好且符合郎伯比尔定律。取实验的吸收截面作为标准参考吸收截面,对相同浓度汞蒸气横向对比及不同浓度汞蒸气纵向对比,浓度误差最大为7.45%,表明渗透管法的稳定性较好且精度较高,验证了渗透管法作为汞标气法的可行性。在渗透管实验中加入SO₂,气态汞浓度测量误差最大为12.82%,说明SO₂对汞吸收度测量产生一定程度的干扰。汞饱和蒸气法实验中,以渗透管为基准测得的最大误差在标准允许误差之内,表明2种校准方法具有一致性。但汞饱和蒸气法与渗透管法相比,其重复性及精度仍有不足,待提升空间较大。     

固含量对聚砜膜透湿性能的影响

选择廉价易得的聚砜为原料,以相转化法制备了聚砜膜.测量了膜的湿交换效率、传质系数、渗透速率、水蒸气吸附量、静态接触角等透湿性能;讨论了铸膜液中固含量的变化对膜透湿性能的影响.研究结果表明,膜水蒸气渗透的湿交换效率随着聚砜浓度的增大而降低;在保持铸膜液中聚砜不变的情况下,加入添加剂PVP可以使孔隙率增大,加入季铵盐能有效提高膜表面的亲水性,从而改善其透湿性能.     

冷侧真空度对减压膜蒸馏过程影响的研究

用ＰＴＦＥ膜实验研究了冷侧真空度对减压膜蒸馏过程的影响．实验结果表明，随冷侧真空度的提高，蒸汽的渗透通量增加，分离率也增加．渗透通量和膜两侧的蒸汽压差成正比．若真空度很高，且冷侧的绝压比膜冷侧的饱和蒸汽压低时，渗透通量有剧增的趋势．渗透通量和膜的孔径大小有关，孔径越大，通量越大．     

增重法与减重法在不同包装材料中的应用

目的探究基于称重法原理的增重法与减重法在不同包材领域内的应用范围。方法避免人工、环境等引入测试误差导致的对比偏差,采用透湿试验腔内自动称量的智能检测仪器,依据ASTM E96标准方法中的增重法与减重法,测试并比较在不同温湿度实验条件下塑料薄膜、纸铝塑复合膜、人造皮革、无纺布等7种不同材质与阻湿性样品的水蒸气透过率。结果纸铝塑复合膜、人造皮革及无纺布样品分别利用增重法和减重法所测得的水蒸气透过率结果有明显差别,而其余4种样品差值不明显;人造皮革样品的增重法实验结果高于减重法的结果,而纸铝塑复合膜及无纺布这2种样品的结果则相反。结论增重法与减重法在测试水蒸气透过率时并非在任何条件下均适用于所有包装材料,应根据样品的材质、结构、使用环境条件及实际用途等因素合理选用增重法或减重法进行检测。     

Ozone and water-vapor measurements by Raman lidar in the planetary boundary layer: error sources and field measurements

A new lidar instrument has been developed to measure tropospheric ozone and water vapor at low altitude. The lidar uses Raman scattering of an UV beam from atmospheric nitrogen, oxygen, and water vapor to retrieve ozone and water-vapor vertical profiles. By numerical simulation we investigate the sensitivity of the method to both atmospheric and device perturbations. The aerosol optical effect in the planetary boundary layer, ozone interference in water-vapor retrieval, statistical error, optical cross talk between Raman-shifted channels, and optical cross talk between an elastically backscattered signal in Raman-shifted signals and an afterpulse effect are studied in detail. In support of the main conclusions of this model study, time series of ozone and water vapor obtained at the Swiss Federal Institute of Technology in Lausanne and during a field campaign in Crete are presented. They are compared with point monitor and balloon sounding measurements for daytime and nighttime conditions.     

空调室内机换热器的整体数值模拟

本文对贯流风机和换热器组成的整体室内机进行结构设计,建立了室内机的三维数值模型,以干空气和水蒸汽两种流体为流体介质,并利用CFD软件在设计边界条件下做三维流场数值模拟,主要分析了三维的室内机定常等温流动的性能参数和内流特性。采用密度干扰方法对水蒸汽的凝结参数近似处理,用Fluent中的UDF（用户自定义函数）予以实现,确定出了空调器室内机的流量——压降等外特性曲线,与实验数据匹配较好。     

A Predictive Instrument for Sensitive and Expedited Measurement of Ultra-Barrier Permeation

The reliable operation of flexible display devices poses a significant engineering challenge regarding the metrology of high barriers against water vapor. No reliable results have been reported in the range of 10^–6 g∙(m²∙d)⁻¹, and there is no standard ultra-barrier for calibration. To detect trace amount of water vapor permeation through an ultra-barrier with extremely high sensitivity and a greatly reduced test period, a predictive instrument was developed by integrating permeation models into high-sensitivity mass spectrometry measurement based on dynamic accumulation, detection, and evacuation of the permeant. Detection reliability was ensured by means of calibration using a standard polymer sample. After calibration, the lower detection limit for water vapor permeation is in the range of 10^–7 g∙(m²∙d)⁻¹, which satisfies the ultra-barrier requirement. Predictive permeation models were developed and evaluated using experimental data so that the steady-state permeation rate can be forecasted from non-steady-state results, thus enabling effective measurement of ultra-barrier permeation within a significantly shorter test period.     

不同包装方式对大米保鲜效果影响的研究

高温高湿条件下,不同包装方式对大米品质变化的影响进行分析研究,得出大米品质变化的影响规律.在贮藏初始阶段,环境高温是大米失水的诱因;在贮藏期间,包装材料的透湿性使包装内相对湿度上升,大米吸水.通过测定霉菌数量、分析包装袋内挥发性气体成分及浓度、测定大米光透差等,得出竹炭以其优越的吸附气体特性可以有效地调节包装袋内环境相对湿度和氧气含量等,确保贮藏期间大米的品质.     

Detection of drug-membrane interactions in individual phospholipid vesicles by confocal Raman microscopy

Optical-trapping confocal Raman microscopy is developed as a method to study the interactions of drugs or other compounds with the membranes of individual phospholipid vesicles. This technique allows membrane disorder, permeability, and drug localization to be assessed without the need for labeling of the membrane or the compounds of interest. We have applied this technique to study the interactions of two nonsteroidal antiinflammatory drugs, salicylate and ibuprofen, with vesicles prepared from 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). The results show that both salicylate and ibuprofen increase membrane disorder, as determined from increases in the Raman scattering from gauche conformers in the phospholipid acyl chains. By monitoring the Raman scattering of the drug molecules in optically trapped DMPC vesicles, the membrane permeability and partitioning of the drugs could be determined; the spatial distributions of the drugs were also measured by scanning the laser focus through surface-adhered 1,2-dipalmitoyl-sn-glycero-3-phosphocholine vesicles, producing a profile of the vesicle and its contents. Though the membrane is permeable to both drugs, ibuprofen preferentially accumulates in the membrane, whereas salicylate does not. The measured ibuprofen accumulation agrees quantitatively with the water/octanol partition coefficient of the drug and the estimated volume of the lipid membrane. The results suggest that ibuprofen localizes in the hydrophobic acyl chain region of the membrane, whereas salicylate weakly associates with the phospholipid headgroups.     

螺旋天线原油含水率测量仪的误差分析与校准

天线是射频法原油含水率测量仪的关键部件。分析采用平行天线和螺旋天线的含水率测量仪在检测原理上的差异,使用研制的螺旋天线原油含水率测量仪进行含水率重复性实验,实验数据分析表明,含水率在40%-80%时,由于原油发生相变,在该区间,含水率测量仪的线性度变差。针对上述问题设计含水率测量误差校准方法及流程,采用分段线性插值法进行含水率全区间测量误差校准,在模拟管道平台和油田井场进行多次重复实验。实验结果表明:所研制螺旋天线含水率测量仪可实现全区间含水率测量,和油田仍普遍使用的蒸馏法含水率测量方法相比,含水率测量误差在5%以内。该仪器可为数字化油田、智能分层采油和注水提供含水率测量数据。     

在多齿分度台上用三位置比较法检定多面棱体的研究

应用数据统计分析方法对在多齿分度台上用三位置比较法及排列互比法了多面棱体工作角偏差进行了比较，运用谐波分析法分析了多齿分度台的分度误差，找到了在一般情况下用三位置比较法检定了多面棱体接近排列比法的结果的理论依据，提出了用多位置比较法检测圆分度器件或仪器的分度误差，提高了工作效率。     

Comparison of some coating techniques to fabricate barrier layers on packaging materials

Atomic layer deposition (ALD), electron beam evaporation, magnetron sputtering and a sol-gel method were used to deposit thin aluminum oxide coatings onto two different fiber-based packaging materials of commercial board grades coated with synthetic and biodegradable polymers. Significant decreases in both the water vapor and oxygen permeation rates were observed. With each technique the barrier performance was improved. However, among the techniques tested ALD was found to be most suitable. Our results moreover revealed that biodegradable polylactic acid-coated paperboard with a 25-nm thick layer of aluminum oxide grown by ALD on top of it showed promising barrier characteristics against water vapor and oxygen.     

变压膜渗透空气分离制氧实验研究

在稳态膜渗透的基础上提出了一种新的非稳态渗透流程。该流程是一种循环操作过程,每一周期包含加压、抽真空以及排空三个阶段。实验研究了加压时间、抽真空时间和排空时间对空气分离制氧的产品平均纯度、平均流量和回收率的影响,并与稳态渗透实验结果进行了比较。结果表明,当富氧纯度相同时,变压渗透过程能够得到比稳态渗透更高的氧气回收率和富氧流量。     

压缩空气脱湿和乙醇气相脱水的集成膜过程研究

采用聚酰亚胺中空纤维膜以气流吹扫操作方式进行乙醇气相脱水研究 ,干燥的吹扫气流由压缩空气膜法脱湿组件提供 ,此两过程构成了集成膜过程 ;讨论了膜材料改性、吹扫气流的湿度和流速、操作温度等条件对乙醇脱水效率的影响 .     

蒸汽渗透技术及其应用

介绍了蒸汽渗透膜分离技术的工作原理、分离性能的评价指标以及影响因素,并与渗透汽化技术进行比较,总结了两过程的异同,指出了蒸汽渗透过程在技术上和经济上的优势,概括了蒸汽渗透技术在工业上的应用.作为新型的膜分离技术,蒸汽渗透技术有较强的市场竞每力.     

Reducing the Uncertainty of Industrial Trace Humidity Generators through NIST Permeation-Tube Calibration

Permeation-tube moisture generators (PTGs) are commonly used by the semiconductor industry as transfer standards for the calibration of hygrometer systems measuring trace amounts of water vapor in gases (water vapor mole fractions typically below 1 × 10⁻⁶). They are relatively simple devices that generate a steady stream of humidified gas by diluting water vapor delivered at a constant rate from a permeable capsule with precisely metered purified gas, usually nitrogen. Here a new calibration service enabling the measurement of PTG permeation rates directly in terms of NIST primary standards of trace humidity generation is described. Rather than using commonly employed gravimetric methods for permeation-tube calibration, the method applied here links the permeation rate of the permeation tube to the thermodynamic properties of ice. Using a hygrometer based on cavity ringdown spectroscopy, we compare the water vapor concentrations produced by the NIST low frost-point generator (LFPG) and a specially constructed PTG containing the permeation tube undergoing calibration. A least squares fit of the data determines the permeation rate of the tube under test. We describe the calibration system, experimental procedure and present sample calibration data. The expanded relative uncertainty of NIST permeation-tube calibrations is 1.8% with a coverage factor k = 2, dominated by the Type A uncertainties.     

Gas injection membrane extraction for fast on-line analysis using GC detection

Membrane extraction has been interfaced with gas chromatography and mass spectroscopy for the analysis of volatile organics in water. The vacuum in a mass spectrometer provides fast mass transport. The time required to complete permeation in a GC interface can be fairly long, because the positive pressure of the carrier gas on the permeate side slows down the analyte permeation. The aqueous boundary layer formed on the membrane is considered to be the biggest contributor to the resistance to mass transfer. Another issue is the dispersion of analyte in the aqueous stream, which broadens the input pulse to the membrane. The overall effect of these two factors is to increase the analysis time. Gas injection of aqueous samples is presented in this paper to address these issues. Gas injection reduces the formation of boundary layer, and increases the overall diffusion coefficient seven times. Axial mixing of the sample with a gaseous eluent is minimal, and this eliminates the tailing in permeation profiles. The overall membrane extraction is found to be significantly faster when a gas is used to inject an aqueous sample. This method is also simpler in terms of instrumentation and operational procedures.     

Principle and experiment of vibrating suction method for wall-climbing robot

This paper presents a new suction method used for wall-climbing robots. The basic idea of this method is that the vacuum can be generated inside a suction cup attaching on a surface, if the suction cup is directly driven by a periodically vibrating force. In this paper, two types of vibrating forces are proposed, one in sinusoidal mode, and the another in square wave mode. Based on Bernoulli’s equation, it is found that the vacuum degree in the suction cup is mainly determined by two parameters of the vibrating forces, namely the amplitude and frequency. To verify the validity of the analyses, an experimental platform was developed, and a series of vibrating experiments were performed. The results indicate that the vibrating suction method can definitely produce continuous vacuum, and also verify the basic relationship between the vacuum degree and the two vibrating force parameters. The minimum average air pressure of the two vibrating modes were also compared. Finally, the feasibility of the vibrating suction method was basically testified on a caterpillar wall-climbing robot.     

Enhancement of extraction efficiency and reduction of boundary layer effects in pulse introduction membrane extraction

Membrane separation has emerged as an attractive alternative for interfacing an extraction step directly to a gas chromatograph or to a mass spectrometer. In pulse introduction (or flow injection type) membrane extraction, a sample pulse is introduced onto an eluent stream that transports it onto the membrane. Since a fixed sample volume is injected, the detector response is directly proportional to the extraction efficiency. This in turn depends on membrane module design, flow conditions, etc. Also, when water contacts a membrane, a static boundary layer is formed at the membrane surface that serves as an additional diffusional barrier to the permeation process. Consequently, permeation slows down, which lowers the speed of analysis. In this paper, methods of increasing the extraction efficiency and decreasing boundary layer effects are presented. The goal is to have higher sensitivity at a shorter analysis time. A stream of nitrogen is introduced into the membrane after sample elution to eliminate the aqueous boundary layer. This technique is found to be effective not only for faster analysis, but also for increasing extraction efficiency.