In Situ Lubrication with Boric Acid: Powder Delivery of an Environmentally Benign Solid Lubricant

In situ deposition of boric acid in dry powder form is investigated as a potential environmentally benign solid lubricant for sliding metal contacts. Boric acid is widely used in industrial processes and agriculture, is not classified as a pollutant by EPA, and produces no serious illnesses or carcinogenic effects from exposure to solutions or aerosols. In this study, boric acid powder is aerosolized and entrained in a low-velocity jet of nitrogen gas, which is directed at a self-mated 302 SS sliding contact in a rotating pin-on-disc tribometer. The effects of powder flow rate, sliding speed, normal load, and track diameter on coefficient of friction and wear rate are investigated. Friction coefficients below μ = 0.1 can be consistently reached and maintained as long as the powder flow continues. Wear rates are reduced over 2 orders of magnitude.     

Atmospherically relevant ion chemistry of ozone and its cation

The importance of ionic processes that occur in terrestrial, planetary, and stellar atmospheres is receiving increasing recognition. Actually, ions play important, often crucial, roles in a variety of atmospheric processes throughout the universe, and a strong link with the neutral chemistry is also apparent. In the terrestrial atmosphere, the ionic reactions are most relevant in those transient and fleeting events, e.g., lightning, coronas (in thunderstorm clouds and along power lines), where the local ion density is much higher than in unperturbed air, and the chemical systems are typically far from equilibrium. In such cases, ozone, a key molecule for the terrestrial atmosphere, is also present in high local concentrations; it is formed from O(2) by the same transient event. Accordingly, this review provides a survey of the positive ion chemistry of ozone with several of the most important "atmospheric" species: the reactions, the products, and the importance of the examined processes are discussed also in the light of the local thermodynamic disequilibrium (LTD) approach to the chemistry of transient atmospheric events. In all such studies, mass spectrometry is traditionally, and remains today, the experimental technique of choice. The novel application of mass spectrometry to the study of neutral species (NRMS), highly successful for the preparation and positive detection of long-sought, otherwise inaccessible, short-lived neutrals, makes mass spectrometry the most powerful tool now available for the study of the species and processes that are relevant to atmospheric chemistry. Selected examples of the interlink between the neutral and the ionic chemistry are also illustrated.     

Numerical modeling of combustion processes and pollutant formations in direct-injection diesel engines

The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and pollutant formation in the direct injection diesel engine. Due to the ability for interactively describing the transient behaviors of local flame structures with CFD solver, the RIF concept has the capabilities to predict the auto-ignition and subsequent flame propagation in the diesel engine combustion chamber as well as to effectively account for the detailed mechanisms of soot formation, NO_X formation including thermal NO path, prompt and nitrous NO_X formation, and reburning process. Special emphasis is given to the turbulent combustion model which properly accounts for vaporization effects on the mixture fraction fluctuations and the pdf model. The results of numerical modeling using the RIF concept are compared with experimental data and with numerical results of the commonly applied procedure which the low-temperature and high-temperature oxidation processes are represented by the Shell ignition model and the eddy dissipation model, respectively. Numerical results indicate that the RIF approach including the vaporization effect on turbulent spray combustion process successfully predicts the ignition delay time and location as well as the pollutant formation.     

臭氧对蔬菜中农药残留降解效果的研究

详细研究了臭氧对蔬菜中不同种类农药残留的降解作用,并考察了水在去除农药残留中的贡献.结果表明,水对去除蔬菜中农药残留有重要作用,臭氧对有机磷类和拟除虫菊酯类农药残留的降解有明显的促进作用,但对灭多威降解效果很不明显.     

不同消毒法对动物医院诊室消毒效果观察

本文将臭氧净化消毒法与紫外线空气照射消毒法进行比较。采用平板沉降法进行空气采样,计算不同消毒方法在消毒进行10min,20min,30min时和消毒后30min的杀菌率。结果显示,臭氧消毒30min时杀菌率为92.6%,明显高于紫外线消毒的消毒杀菌率75.8%。湿度60%以上,开机30min臭氧杀菌率为98.4%,紫外线消毒组杀菌率仅为28.6%。应用臭氧净化空气消毒法具有高效、适用性广等特点。     

Preparation and accurate measurement of pure ozone

Preparation of high purity ozone as well as precise and accurate measurement of its pressure are metrological requirements that are difficult to meet due to ozone decomposition occurring in pressure sensors. The most stable and precise transducer heads are heated and, therefore, prone to accelerated ozone decomposition, limiting measurement accuracy and compromising purity. Here, we describe a vacuum system and a method for ozone production, suitable to accurately determine the pressure of pure ozone by avoiding the problem of decomposition. We use an inert gas in a particularly designed buffer volume and can thus achieve high measurement accuracy and negligible degradation of ozone with purities of 99.8% or better. The high degree of purity is ensured by comprehensive compositional analyses of ozone samples. The method may also be applied to other reactive gases.     

CO2-TEA,MID-INFRARED,LASER-BASED DIAL SYSTEM: FEATURING OZONE DYNAMICS DURING A “VEHICLE-FREE” DAY

ABSTRACT

Long-path ozone integrated measurements with a CO₂-laser DIAL system were performed in Madrid City during a “vehicle-free” day. The results showed a strong correlation between human activity and ozone photochemical generation. The ozone concentration follows, even quantitatively, the same trend of the overall traffic intensity as long as both UV-B radiation and NO₂ are present. An average decrease of 12.3±1.2% of the intensity of vehicle traffic during the “free-vehicle” day resulted in a lowering the ozone burden by almost 14.4±1.4%. This new type of information can stimulate the development of local models to understand the dynamic underlying urban pollution. The results, indeed, show the effectiveness of such a measure to reduce the ozone burden on human and plant health.     

风云三号A星紫外臭氧垂直探测仪反演产品的比较和评估

为了考察和评估我国首次自主研制并由新一代极地轨道气象卫星风云三号携带的紫外臭氧垂直探测仪SBUS的观测数据和反演产品的精度和稳定性,利用SBUS在轨观测数据开展了臭氧垂直氧廓线反演试验,并将反演产品与NO-AA卫星同类仪器SBUV/2产品数据进行了系统比较。首先使用自主研发的风云三号紫外臭氧垂直廓线反演算法FY_V1.0开展臭氧廓线反演试验,输入数据为SBUS2008年7月17日～8月30日在轨观测数据。然后,采用3种方法,即匹配像元数据直接比较,赤道地区平均反演廓线比较以及反演廓线与先验廓线残差比较,将反演结果与SBUV/2产品进行了比较。最后,基于各种比较结果进行分析和评估。结果显示,与NOAA-16和17卫星SBUV/2反演产品相比,SBUS反演产品多数高度层相对偏差百分率在±10%之间,部分层相对偏差达到±15%;在20°N～20°S比较平均反演臭氧垂直廓线,最大差异为5.4DU,最小差异为0,多数在±0.3DU之间;比较反演廓线与先验廓线的残差表明,较大残差发生的高度以及残差正负性等方面存在明显差异。结论认为,在未对数据做任何订正的条件下,SBUS反演臭氧垂直廓线产品在多数高度层精度尚可,但是,与SBUV/2产品相比,SBUS获取的臭氧垂直廓线存在较大的系统性偏差,需要通过与SBUV/2的交叉定标进行订正。     

大气临边观测中视轴临边指向精度的在轨补偿

为提高大气臭氧观测中的临边大气反演精度,克服臭氧探测仪在轨热变形和卫星姿态误差对临边指向精度的影响,建立了在轨视轴临边指向的精度补偿方法。通过分析低星等恒星的能量和观测时机,设计合适的恒星观测窗口和积分时间;采用平板玻璃获取星点像的弥散斑,用阈值距心法计算恒星像在像面上的位置;然后根据卫星轨道和探测仪的几何结构,设计临边指向精度的在轨补偿方法并分析了补偿后的临边指向精度。地面对星观测实验的结果表明:采用恒星定位补偿法,可使星点像的定位误差小于1.83″,当前视轴的指向误差控制在±3.08″以内;在编码器的位置重复精度为±2.47″的条件下,使临边观测光轴位置上的扫描镜定位误差控制在±3.95″以内,臭氧探测仪临边指向精度达到±7.9″以上,完全满足反演所需的指向精度优于±12.4″的要求。     

基于差分吸收激光雷达和数值模式探测杭州夏季臭氧分布

为获取杭州市夏季臭氧浓度时空分布特征和气象要素对臭氧浓度的影响,利用臭氧差分吸收激光雷达开展观测,同时利用WRF-Chem模式模拟臭氧时空特征和气象要素。实验结果表明:臭氧浓度模拟结果与激光雷达的观测结果具有很好的一致性。2016年夏季,杭州市18天内发生了4次臭氧重污染,每次持续2到5天,最高浓度达550nL/L。高空1~2km存在较高浓度的臭氧污染层,并存在垂直和水平传输,对近地面臭氧污染有明显影响。近地面臭氧浓度平均最低值出现在凌晨2时左右,为75nL/L;平均浓度最高值在中午12时左右出现,为90nL/L。近地面臭氧浓度的日变化明显,而高空的臭氧浓度日变化不明显。臭氧差分吸收激光雷达系统对臭氧时空分布的探测是可靠的。强太阳辐射、高温、低湿都是臭氧污染形成的有利环境条件,而强风对局地臭氧有扩散作用,降雨对臭氧有很好的消除作用。     

Research on liquid lubricants for space mechanisms

Four research areas at the NASA Glenn Research Center in the United States, involving the tribology of space mechanisms, are highlighted. These areas include: soluble boundary lubrication additives for perfluoropolyether liquid lubricants, a Pennzane® dewetting phenomenon, the effect of non‐ozone depleting chemical bearing cleaning processes on bearing lifetimes, and the development of a new class of liquid lubricants based on silahydrocarbons.     

Ultraviolet exposure enhanced silicon direct bonding

Ultraviolet (UV) exposure, as an additional technique following the traditional wet chemical activation processes, is applied to enhance hydrophilic silicon direct bonding. The effects of UV exposure on silicon wafers’ nano-topography and bonding strength are studied. It is found that the surface roughness of silicon wafers initially decreases and then increases with UV exposure time, and the bonding strength increases and then decreases accordingly. The correlations of annealing temperature and annealing time vs. bonding strength are experimentally explored. Results indicate that the bonding strength increases sharply then gently with increasing annealing temperature and annealing time using UV exposure. Besides, the reliability of silicon direct bonding with UV exposure enhancement after the high/low temperature cycle test, constant temperature and humidity test, vibration test and shock test is investigated. It follows from the results that the bonding strength of silicon wafer pairs with UV exposure decreases after the environmental tests, whereas the residual strength is still higher than that without UV exposure, and the variation trends of bonding strength vs. UV exposure time, annealing temperature and annealing time remain unchanged. Therefore, following the traditional wet chemical activation processes, appropriate UV exposure (about three minutes in this study) is effective and promising to enhance silicon direct bonding.     

Ultraviolet exposure enhanced silicon direct bonding

Ultraviolet (UV) exposure, as an additional technique following the traditional wet chemical activation processes, is applied to enhance hydrophilic silicon direct bonding. The effects of UV exposure on silicon wafers’ nano-topography and bonding strength are studied. It is found that the surface roughness of silicon wafers initially decreases and then increases with UV exposure time, and the bonding strength increases and then decreases accordingly. The correlations of annealing temperature and annealing time vs. bonding strength are experimentally explored. Results indicate that the bonding strength increases sharply then gently with increasing annealing temperature and annealing time using UV exposure. Besides, the reliability of silicon direct bonding with UV exposure enhancement after the high/low temperature cycle test, constant temperature and humidity test, vibration test and shock test is investigated. It follows from the results that the bonding strength of silicon wafer pairs with UV exposure decreases after the environmental tests, whereas the residual strength is still higher than that without UV exposure, and the variation trends of bonding strength vs. UV exposure time, annealing temperature and annealing time remain unchanged. Therefore, following the traditional wet chemical activation processes, appropriate UV exposure (about three minutes in this study) is effective and promising to enhance silicon direct bonding.     

Study of the Adsorption of Ozone on the Surface of Ferric Oxide by Reversed-Flow Inverse Gas Chromatography

Abstract

In this work, in order to describe the impact of ozone on ferric oxide – a common constituent of building materials – in purely scientific terms, a novel methodology that of Reversed Flow–Inverse Gas Chromatography (RF–IGC or RF–GC) is proposed. Five important physicochemical quantities concerning adsorption of ozone on the solid surface of ferric oxide are determined, in five temperatures, in a time-resolved way. By means of a simple PC-program, the values of local adsorption energy, local adsorption isotherm, local monolayer capacity, probability density function for adsorption energy, and energy from lateral interactions are calculated. Thus, the role of surface heterogeneity, lateral interactions and different distributions of active sites (surface topography) on the adsorption of ozone on the surface of ferric oxide is analyzed in the way the RF–IGC method has it developed.     

GCXD-1000型床单位消毒器消毒方法的应用

介绍了GCXD－1000型床位单位消毒器臭氧消毒方法，并用GCXD－1000型床位单位消毒器和紫外线灯对两间病房同时进行消毒对比。结果说明两种方法在物体表面消毒效果中无明显差异；在病房空气消毒中，前者略优于后者；在物体各面消毒效果中，前者明显胜于后者。结论：臭氧杀菌范围比紫外线更为广泛，更适用于病房消毒。     

Hydrodynamic profiling and grit blasting of low-carbon steel surfaces

The surface preparation by hydrodynamic profiling and grit blasting of low-carbon steel specimens is investigated. Roughness measurements and SEM imaging show that hydrodynamic profiling forms a surface profile with a high roughness and without surface contamination. In contrast, grit-blasted specimens show grit residues embedded in the substrate surface. The debris collected after hydrodynamic profiling show a rounded shape suggesting that the material is removed due to low-cycle fatigue. The debris produced by grit blasting appear in the shape of platelets and flow-type chips suggesting a mixture of micro-cutting and forging–extrusion. The influence of stand-off distance, exposure time, and flow speed on the profiling process are also studied. The results identified the optimum operational conditions for hydrodynamic profiling. Fatigue by impacting fluid drops is suggested to be the dominant material failure mode. However, results of a comparative calculation of the incubation drop impact frequency suggests that fatigue is accompanied by energy-dissipative processes.     

便携式飞行时间质谱仪在汽车尾气在线检测中的应用

汽车尾气中的挥发性有机物（VOCs）是主要的人为排放污染源之一,排放到大气环境中的VOCs具有很高的反应活性,能够参与臭氧的生成,是形成二次有机气溶胶等污染物的重要前体物质。因此,研制开发适用于现场实时、在线检测VOCs的便携式分析仪器,是现代科学仪器发展的重要方向之一。本工作利用苯系物标准气体对自行研制的便携式膜进样真空紫外灯单光子电离飞行时间质谱仪整机进行性能测试,仪器的质量分辨率优于350,质量精度优于1×10^-4,对苯系物的检测限可达μg/m³级,动态范围优于3个数量级,仪器的总质量小于25 kg。将仪器放置户外对汽车尾气进行现场测试,基于该仪器高时间分辨率的特点,初步研究了汽车尾气排放VOCs的变化趋势与发动机工作状态的相关性。该仪器有望应用于环境应急事故、现场长期监测、化工园区生产工艺过程监控以及无组织排放等领域。     

SPME-GC/MS测定丙烯酸丁酯中苯胺

针对进口丙烯酸丁酯中微量污染物所引起的变色反应,建立相应的测试方法,采用气-质联用对样品中的污染物进行定量分析与结构鉴定;运用固相微萃取方法对生色反应的产物进行有效的富集,并进行定性分析;在生色反应发生的条件下,模拟生色反应中三种产物的有机合成反应,确定引起变色的物质。结果表明,引起进口丙烯酸丁酯变色反应的污染物为苯胺所致。在苯胺浓度为0.30‰～3.00‰的范围内,本方法有很好的线性关系,其相关系数R=0.9995。     

Rotary-vane compressors: Some technical aspects of long-life lubricants

Compressors are used all over the world for various individual applications; the current application concerns their use in the ozone process of water treatment. Technical data on different mineral and synthetic lubricants are given. In particular, a new oil was chosen for investigation. Field testing was undertaken over more than 6000 h on two different locations. Used oil monitoring was conducted by sampling during the experiment; analyses of physical and chemical parameters were made and their kinetics are described. Wear, viscometrics and ozone process interaction are discussed in this study.     

激光片光浓度场测量系统及其在风洞模拟中的应用

为在大型环境风洞中模拟大气污染物迁移扩散状况,开发出污染物浓度激光片光测量系统和污染物发放系统。基于激光片光浓度场测量系统,风洞模拟得到城市环境下点、线和面源污染物的扩散分布图案。基于风洞试验工况的边界条件,计算流体动力学(CFD)仿真得到污染物扩散分布,CFD仿真结果和激光片光浓度测量结果,两者定性一致,达到了相互印证的效果。将研究开发的激光片光浓度场测量系统和定量采样方法相结合,有望实现风洞试验中污染物浓度场的定量测试。