Outgoing longwave flux estimation: improvement of angular modelling using spectral information

A radiance-to-flux conversion is needed to estimate radiative fluxes at the top of the atmosphere from directional measurements made by broadband (BB) radiometers on satellites. Such a conversion is known to be one of the major sources of error in the resulting instantaneous shortwave and longwave fluxes. This paper analyzes the possibility to improve the radiance-to-flux conversion for the longwave radiation when spectral information about the radiation is available through a set of narrow-band (NB) measurements. The study is based on a database of spectral radiance fields at the top of the atmosphere built using radiative transfer computation. The analysis of this database shows that there exists a certain degree of correlation between the angular and the spectral behaviors of the radiation field. According to the type and the accuracy of the spectral information, this correlation allows a 25-55% reduction of the error introduced by the radiance-to-flux conversion with respect to a simple model that uses only broadband information. The method discussed in this paper might be used when broadband radiometer and spectral imager data are available together like the combination of Geostationary Earth Radiation Budget (GERB) and Spinning Enhanced Visible and Infrared Radiometer Imager (SEVIRI) or the combination of CERES and MODIS.     

镁合金消失模铸造的优势及关键

对常见镁合金铸造工艺作了分析和总结，对镁合金消失模工艺的优缺点作了客观分析；提出了可控气氛、可控压力镁合金消失模铸造新工艺；认为该工艺是一种非常适合镁合金液态成形的新的精密铸造方法，具有设备投资小、铸件成本低、内在质量好、精度高、生产率高的优势，同时可以较好地解决镁合金液态成形过程中易氧化燃烧的问题。     

基于宏基因组分析气调保鲜卤鸭掌中微生物污染

摘 要:目的 研究气调保鲜卤鸭掌中微生物污染的菌相组成及主要致病菌、致病基因与耐药基因的相关情况。方法 从市场采购气调保鲜鸭掌样品,提取DNA,检测DNA浓度,测序、注释,菌种鉴定与丰度分析等,并检验菌落总数。结果 菌落总数结果为1200CFU/g,符合食品安全国家标准要求,DNA浓度为6.54ng/μL存在一定层度微生物污染;采用宏基因组研究方法分析菌相组成,共测出48种微生物,诺卡氏菌丰度最高约75%,大肠杆菌、不动杆菌、慢生根瘤菌、盐单胞菌、克雷伯菌、沙门氏菌、弧菌丰度大于1%;比对SEED数据库,检出对稳态铜的抗性基因;比对KEGG数据库,发现13种代谢通路可感染宿主;比对ARBD数据库,发现4个多重耐药性基因,1个氯霉素抗性基因。结论 宏基因组结合传统微生物研究方法可有效分析样品中微生物状况,并能从分子层面研究致病因子,以及耐药基因的传播机理,对于微生物污染防控,耐药基因传播阻断机制,有重要的借鉴性意义。     

Corrosivity of atmosphere toward structural metals and mapping the continental Russian territory

ABSTRACT

The corrosivity of atmosphere in the continental territory of Russia toward carbon steel, zinc, copper and aluminium was determined and estimated. The atmosphere corrosivity was determined from experimental data on first-year corrosion losses in representative test locations. The atmosphere corrosivity was estimated using first-year corrosion losses of structural materials calculated by means of dose–response functions: new ones (DRF^N) and those presented in ISO 9223 (DRF^S). Estimation of atmosphere corrosivity in the Russian Federation (RF) territory was performed using the data bank of the Institute of physical chemistry and electrochemistry of the Russian Academy of Sciences containing long-term annual average meteorological atmosphere parameters. The mapping of RF continental territory by categories of atmosphere corrosivity is presented. The atmosphere corrosivities estimated by DRF^N and DRF^S for each metal are compared. It has been shown that DRF^N provides more reliable atmosphere corrosivity estimates.     

Sintering and characterization of calcium alumino-titanate-SiC composite refractory fired in reducing and oxidizing atmospheres

Calcium alumino-titanate (CAT) is characterized by low thermal conductivity, low thermal expansion coefficient, and high refractoriness. The phase changes and microstructural evolution of a CAT-SiC composite refractory are investigated using X-ray diffraction, scanning electron microscopy, and thermodynamic analysis. Results show that the cold crush strengths of specimens fired in an oxidizing atmosphere are higher than those of specimens fired in a reducing atmosphere. In a reducing atmosphere, composites with SiO₂ addition fired at 1350 °C exhibited the highest strengths. Good bonding occurred between different local reaction zones in specimens fired in an oxidizing atmosphere compared to those fired in a reducing atmosphere. Furthermore, a coexistent state of CA₆ and corundum in CAT is observed in specimens fired in a reducing atmosphere, and mullite whisker growth occurred for composites without AlF₃·3H₂O addition, where the TiO₂ present in CAT acts as a catalyst.     

Effect of atmosphere on microwave heating of titanium powder

Abstract

Microwave irradiation was performed using compacted Ti powder in three types of atmosphere, namely, Ar gas, N₂ gas and air. The temperature increased slightly in the early stage of microwave irradiation and then remained almost unchanged. Thereafter, abrupt temperature rise and drop occurred. The temperature then remained almost unchanged in the late stage of microwave irradiation. The time from which the abrupt temperature rise and drop occurred was varied by the atmosphere. The maximum temperature in microwave irradiation in Ar gas was near the melting point of Ti, while those in N₂ gas and air were beyond this melting point. Although a TiO₂ layer was formed near the upper surface of the compacted powder after microwave irradiation, α-TiN and TiN were produced in its interior. The microwave heating behaviour and microstructure of the compacted powder after microwave irradiation depended on the atmosphere and the amount of air contamination in it.     

解放思想，争国际一流，开创中国特色城市规划新局面

该文对中国特色城市规划争国际一流水平提出了三条标准．认为当前我国规划力量已空前壮大，只要解放思想．就有望创国际一流的新局面。并对特色可能出现的主流、边缘化、对外开放等问题提出相关见解．期望特色应具有中国味儿的氛围、情趣，风采、风韵、     

Single frequency processing of atmospheric radio occultations

Tracking of the radio signals broadcast by the Global Positioning System (GPS) satellites as they are occulted from a GPS receiver by the Earth's atmosphere can provide high resolution vertical profiles of atmospheric refractivity, temperature and water vapour. Most implementations of this radio occultation technique use two GPS frequencies to correct for ionospheric effects. However, during most soundings, one of the frequencies is degraded by the introduction of the so-called Anti-Spoofing (AS) encryption mode. A retrieval method is discussed in this work for periods when only one of the two frequency signals has good quality. This method uses only the frequency with higher signal-to-noise ratio. We illustrate the quality of the atmospheric profiles obtained from such single frequency retrievals using GPS/MET data from the periods where the AS was turned off and the two frequencies were available. The results enable us to ensure the quality of a climate record of thousands of radio occultations collected by GPS/MET during the period with AS encryption, and the data processing of future missions with similar constraints, like IOX, can be performed.     

异常海洋大气条件下红外与微波折射特征差异研究

研究了海上异常折射环境对于雷达微波和远红外波段的影响,利用近海面大气折射环境数值模型以及福建平潭和西沙永兴岛的海洋环境观测数据对两个波段进行了对比.结果表明,当雷达微波出现负折射时,红外波段却出现"波导"超折射特征,但强度和厚度较弱;当微波出现大气波导时,红外波段多为负折射特征.该项研究可为复杂海洋大气环境下两种探测系统的优化配置以及海洋环境对舰载光电探测系统的影响研究提供科学参考.     

On-line control of processing atmospheres for proper sintering of oxidation-sensitive PM steels

Changes of atmosphere composition during sintering of water atomized powder prealloyed with Mn and Cr (up to 2% of both) were studied. Increasing sensitivity to atmosphere purity with increasing alloying elements content was registered. Continuous monitoring of sintering atmosphere composition (CO/CO₂/H₂O) indicates three critical stages during the heating up to final sintering temperature: the importance of rapid atmosphere purification after lubricant decomposition and removal; the reduction of the iron oxide layer by hydrogen at temperatures up to ∼500 °C and by carbon at temperatures around ∼720 °C; the reduction of the spinel oxides on the powder surface at above 900 °C and further reduction of thermodynamically stable surface oxides and mixed internal oxides close to the sintering temperature. The measured ratio of CO/CO₂ indicates favorable thermodynamic conditions for reduction of stable oxides as (Cr,Mn)_xO_y close to sintering temperature (1120 °C) for the applied sintering conditions. The experimental results were confirmed by modeling the metal-gas interactions using the thermodynamic/thermochemical softwares ThermoCalc and HSC Chemistry. The modeling indicates the significance of maintaining a sintering atmosphere with high reducing potential during heating stage for minimizing oxidation before high-temperature carbothermal reduction starts.