滚道磨削中手轮轮廓偏置功能的应用

本文以"咸阳机床厂"生产的内滚道磨床"XYJ-2017"和英国"MATRIX CHURCHILL"公司生产的4703外滚道磨床为例,论述了内、外滚道磨削加工进程中手轮轮廓偏置功能的具体应用。     

Chemical characterization and properties of five deep-sea fish species

Some important flesh properties were determined for the deep-sea species Portuguese dogfish (Centroscymnus coelolepis), leafscale gulper shark (Centrophorus squamosus), black dogfish (Centroscyllium fabricii), roughhead grenadier (Macrourus berglax), and mora/deepsea cod (Mora moro).Chemical composition, water holding capacity, cook loss and shelf-life, as indicated by bacterial counts, were determined. For some of the species investigated, variations could be observed between fish caught in spring and fish caught in summer. The fish used in this study were caught at Hatton Bank in the North Atlantic, where fishing takes place mainly from April to September.     

Retention of folates in cooked,stored and reheated peas,broccoli and potatoes for use in modern large-scale service systems

This study aimed to evaluate retention of folate in vegetables caused by different processes used in modern large-scale service systems and the food industry. The concentration of folates present in raw samples of peas, broccoli and potatoes was measured during different cooking methods, warm and cold holding and reheating. The main folate forms in vegetables, tetrahydrofolates and 5-methyltetrahydrofolates, were analysed using a validated high-performance liquid chromatography (HPLC) method.     

Effect of wind on drying from wet porous building materials surfaces—A simple model in steady state

The effect of wind on drying of wet porous building materials was studied. A model that assumes that evaporation from a material can be expressed by a surface resistance B was used. B gives the maximum drying capacity of a surface. B can be measured assuming that evaporation from the material is proportional to the evaporation from a free water surface, the material porosity and a material constant, K. Experiments were performed to verify the model and to provide material data on B using a wind tunnel. Steady state flow was measured through thin building material specimens mounted in “wet cup” specimen holders. Water was absorbed from the lower side and evaporated from the upper side of the specimens during exposure to wind. Six building materials with large variations in porosity and sorptivity were tested. K was quite constant for each material for wind velocities of 0.15–10 m/s, verifying the model. Wind affected flow more the higher the material sorptivity. Calculation of B at 50% relative humidity and wind velocities 0.15–10 m/s for the six materials is shown in the paper. B=J_h.K.ε/(H_surface-H_environment) with J_h=evaporation rate from free water, ε=material porosity and H=humidity. For concrete with w/c=0,75 at 10 m/s wind velocity, B=0.003 m/day.

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Résumé L'influence du vent sur le séchage des matériaux de construction poreux a été étudiée. On a utilisé un modèle qui estime que le taux d'évaporation d'un matériau peut s'exprimer par une résistance de la surface, B. B exprime la capacité maximal de séchage d'une surface. On peut mesurer B en estimant que l'évaporation de la surface est proportionnelle avec le taux d'évaporation de l'eau liquide libre, la porosité et une constante du matériau, K. Des expérimentations ont été faites utilisant un tunnel de vent pour vérifier le modèle et pour mesurer des données pour calculer B. Le transfert d'eau constant a été mesuré dans des éprouvettes minces absorbant de l'eau au-dessus et évaporant en dessous sous l'influence du vent. Six matériaux de construction de porosités et sorptivités bien variées ont été essayées. K a été constant pour chaque matériau avec vitesse du vent de 0,15–10 m/s. Le modèle est avec cela considéré vérifié. Le vent a plus affecté le transfert de vapeur quand les sorptivités des matériaux ont augmenté. Le calcul de B avec 50% d'humidité relative et vitesse du vent de 0,15–10 m/s est montré dans l'article. B=J_h.K.ε/(H_surface-H_environement) avec J_h=taux d'évaporation d'eau libre, ε=porosité et H=humidité relative (=1 en état saturé). Pour un béton de e/c=0,75 et 10 m/s vitesse de vent B=0,003 m/jour.

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Editorial note The Norvegian Building Research Institute is a RILEM Titular Member.     

Diversity in metabolite production by Fusarium langsethiae, Fusarium poae, and Fusarium sporotrichioides

The production of mycotoxins and other metabolites by 109 strains of Fusarium langsethiae, Fusarium poae, Fusarium sporotrichioides, and F. kyushuense was investigated independently in four laboratories by liquid or gas chromatography analyses of cultural extracts with UV diode array, electron capture, or mass spectrometric detection systems. From the compiled results, it was found that F. langsethiae consistently produced the trichothecenes diacetoxyscirpenol (DAS), T-2 toxin (T-2), HT-2 toxin (HT-2), and neosolaniol (NEO) and, to a lesser extent, some additional trichothecene derivatives. F. langsethiae also produced culmorins, chrysogine (CHRYS), aurofusarin (AUF), and enniatin (EN). F. sporotrichioides showed a metabolite profile similar to that of F. langsethiae, while F. poae had a different profile as 41 of 49 strains produced nivalenol (NIV) and other 8-keto trichothecenes, in addition to DAS and derivatives of this metabolite. Only a trace amount of NIV was detected from one strain of F. kyushuense. In summary, all the three core taxa of this joint study were found to produce trichothecenes. Fusarin C (F-C) was not detected from F. langsethiae, but it was produced by F. poae and F. sporotrichioides. Aurofusarin was only detected from a few strains of F. langsethiae, while nearly all strains of F. poae and F. sporotrichioides produced this compound. In contrast, chrysogine was not detected from F. poae, but was produced by the other two taxa. Production of enniatins was scattered among the three main taxa of this study, whereas beauvericin (BEA) was produced by many strains of F. poae and F. sporotrichioides. Only one odd strain of F. langsethiae (IBT 9959) produced beauvericin. However, the status of this strain is uncertain. By a polyphasic approach using species-specific metabolite profiles, the fruity odour of F. poae, and morphological observations, it was concluded that F. langsethiae, F. poae, and F. sporotrichioides should be regarded as three significant taxa at a species level.     

Enterotoxin formation by Clostridium perfringens during sporulation and vegetative growth

Growth, sporulation and enterotoxin production have been followed for three different strains of Clostridium perfringens on a vegetative (FTG) medium and a sporulation (DS) medium. Enterotoxin production was followed by use of enzyme-linked immunosorbent assay (ELISA). All strains produced enterotoxin under both vegetative growth and sporulation in spite of the fact that one strain is known to be enterotoxin negative. The presumed negative strain produced about the same amount of enterotoxin on both media (1 ng/ml). The two other strains produced about 1000–2000 times more enterotoxin during sporulation than during vegetative growth.     

Database Correlation Method with Error Correction for Emergency Location

The constantly growing number of mobile terminal users increases also the number of mobile originated emergency calls. In the United States mobile terminal location in case of an emergency call was mandated with stringent accuracy requirements by Federal Communications Commission (FCC) in 1996. Since July 2003 emergency call location is required also in the European Union (EU), but contrary to the US, without accuracy limits. The global positioning system (GPS) offers high location accuracy, but the density of GPS-capable terminals is very low. Thus, to be able to provide location estimations for all mobile originated emergency calls nationwide, techniques based on cellular network are preferred. In many cases, however, conventional techniques cannot provide sufficient accuracy. This is typical especially for urban areas, where obstacles in signal propagation path degrade location estimation. In urban areas the mobile terminal user density is high and a substantial part of urban emergency calls are mobile originated requiring accurate location estimation. In this paper, we propose a method for emergency call location in urban areas. This database correlation method (DCM) is complemented by error correction method (ECM) developed in the frame of the EU IST project cellular network optimization based on mobile location (CELLO) [http://www.telecom.ntua.gr/cello/]. In performance evaluations DCM has proven to offer sufficient urban accuracy of 44 m in GSM field trial and 25 m in UMTS simulations. The ECM has been tested and proven to ease the implementation of DCM.     

基于微尺度的列车制动金属镶嵌行为研究

列车制动过程中,无论是踏面制动还是盘式制动都存在金属镶嵌现象,造成车轮踏面与制动盘盘面损伤,从而对车辆运行带来安全隐患.为研究金属镶嵌的形成原因及行为,选取低摩擦因数合成闸瓦与车轮、粉末冶金闸片与制动盘两种摩擦副产生的金属镶嵌物,进行宏观与微观形貌观察、材料物理及力学性能试验和材质成分含量分析.采用有限元软件ABAQU...