几种火焰喷焊自熔性合金层的耐磨性能

研究了不同自熔性合金粉末火焰喷焊层的显微组织与抗磨粒磨损性能，并对其磨面形貌进行了ＳＥＭ观察分析。结果表明，在Ｎｉ６０自熔性合金中加入适量的镍包ＷＣ粉末可明显提高其喷焊层的抗磨粒磨损性能。当ＷＣ的加入量为３５％（ｗｔ）左右时，该喷焊层与６０Ｓｉ２Ｍｎ调质钢相比，相对的耐磨性可提高６倍以上。     

碳钢与不锈钢表面高浓度渗铬法

在氩气气氛下，应用固体渗铬填料法对碳钢、不锈钢作了表面高铬浓度的渗铬处理，探讨了渗铬温度、时间和渗铬组分对渗层表面铬含量、厚度，试样增重和物相组分影响，碳钢、不锈钢的表面渗铬浓度分别达８０－９４ｗｔ％和７０－８２ｗｔ％。     

Development of temperature compensated high elongation resistance strain gauges for use up to 250°C

The paper describes the development and evaluation of temperature compensated high elongation resistance strain gauges for use from room temperature to 250°C. These gauges could be temperature-compensated on steels with coefficient of thermal expansion α = 11 ppm/°C. Thermal output within 250°C was about 1 μm/m/°C and maximum standard deviation of 5 gauges was 34 μm/m. Strain limit was > 4% at room temperature and at 250°C. Gauge factors of different strain ranges at R.T. and at 250°C are tabulated. Some applications are stated.     

Distribution and Fate of Escherichia coli in Lake Michigan Following Contamination with Urban Stormwater and Combined Sewer Overflows

Escherichia coli distribution and persistence in nearshore Lake Michigan were assessed following heavy rains and sanitary sewer overflow (SSO) and combined sewer overflow (CSO) events over a 5-year period, including an 18-day period following 25.4 cm of rainfall in which intensive studies were conducted following multiple CSO and SSO events. E. coli levels in the Milwaukee estuary and harbor following SSO and CSO events ranged from 10⁴ to nearly 10⁵ CFU/100 mL, which were significantly higher (p ≤ 0.05) than levels following rainfall alone. Sites outside of the breakwall but within the contamination plume (e.g., within 2 km of the harbor) were an order of magnitude lower. Locations 2–5 km from the harbor ranged from below detection limits, of < 1 to 5 CFU/100 mL. E. coli levels corrected for dilution based on specific conductivity measurements were lower than what would be expected for loss due to dilution alone, suggesting a combination of die-off and dilution, were responsible for the rapid disappearance of these organisms outside of the harbor. E. coli and fecal coliforms measured concurrently demonstrated that fecal coliforms could be recovered longer than E. coli in the open waters of the lake. E. coli isolated directly from sewage treatment plant influent were found to have a marked increase in antibiotic resistance traits for ten antibiotics commonly used in the human population compared with isolates from two animal sources of fecal pollution. However, E. coli obtained from sewage impacted water (n = 2,513) and from stormwater impacted water (n = 1,465) collected the previous year when there were no sewage overflows, were found to have no significant difference (p < 0.05) in the frequency of resistance when comparing the two conditions. E. coli survival characteristics and population dynamics are most likely influenced by multiple factors in complex systems such as the watershed/estuarine/lake environments of the Great Lakes.     

S—135钢板热轧工艺研究

S—135钢板是水电站用高强耐磨不锈钢板,既要求强度高、韧性好,又要求耐磨、耐蚀性强,生产难度较大。除我厂外,目前国内尚无其它厂家能够生产这种钢板。该钢板在加热轧制,冷却过程中要解决很多技术难点。我们通过采用特殊的控制轧制和控制冷却工艺,很好地解决了诸多技术难点,使S—135钢板的开发研制取得了成功。为电站用高强度耐磨不锈钢生产提供了宝贵的经验,也为控制轧制及控制冷却技术在中板生产行业的应用起到了积极的推动作用。     

Monitoring water quality in reservoirs with IRS-1A-LISS-I

An attempt has been made to quantify the relationship between the variation in IRS-IA-LISS-I (Indian Remote Sensing Satellite-1A Linear Imaging Self-Scanning System) radiance data and field measured change in secchi disc depth. Secchi disc depth was measured for 47 predetermined sampling locations on reservoir surface water. At extinction depth (secchi depth), water samples were collected from all the sampling locations. Suspended sediments of eight locations representing various reaches of the reservoir were selected for mineralogical, particle size and optical properties analysis. The LISS-I radiance value in band 1 (0.45–0.52µm) band 2 (0-52–0.59 µm) and band 3 (0.62–0.68 µm) were used in a regression analysis. The absorption infrared band 4 (0.77–0.86 µm) was not included in the analysis. In these, the dependable variable was secchi depth (SD) and the LISS-I-radiance data was the estimator variable. Forty-seven data sets of 20 October 1988 from Tawa reservoir surface water were used to obtain an estimator equation for SD. The verification of the estimator equation was tested by applying it to a data set of 21 measurements of 28 September 1988 for this reservoir. The coefficient of correlation between observed and estimated values for the 28 September 1988 data set wasr=0.92 for SD, indicating that the equation could accurately predict the water clarity (SD) for this reservoir on new occasions from IRS-IA-LISS-I spectral data. It is shown that mineral composition and optical properties of suspended sediments influence the reflected radiance of water quality. It is concluded that IRS-IA-LISS-I data provide a useful means of mapping water quality in reservoir.     

中型孔径小梯段露天石方深孔水压爆破

介绍了一种石方开挖新技术－－露天石方深孔水压爆破技术。用试验的方法，通过和常规石方爆破进行类比，从而研究了此项新技术在中型孔径小梯段应用条件下的各种爆破参数，并进行了定性和定量分析，得到了一些初步的结论。     

HDPE的耐磨蚀性与抗冲击性的研究

用自制的旋臂式磨蚀实验仪，研究了５种高密度聚乙烯和１种顺丁橡胶改性的高密度聚乙烯，在铁尾矿和铁精矿浆体中的耐磨蚀性。耐磨蚀性最差的是ＨＤＰＥ２２００Ｊ，耐磨蚀性较差的是ＨＤＰＥ６３００Ｍ；ＨＤＰＥ５０００ｓ，６０９８和２４８０的耐磨蚀性较好；ＨＤＰＥ／ｃｉｓ－ＢＲ的耐磨蚀性最好。     

Effect of Microstructure on the Accelerated Creep of 20CrMoV12‐1 and P 91 Steels

In the initial part the change of microstructure for steel X20 CrMoV 121 is discussed in terms of the distribution of carbide precipitates and its effects on accelerated creep resistance and hardness are presented. In the following, experimental results of microstructure and accelerated creep resistance are presented for the steels X20CrMoV 121 and P91 annealed for up to 8760 hours at 650°C and 750°C before the testing. A similar evolution of the distribution of carbide particles of a size above 102 nm is found for both steels, while the accelerated creep resistance is diminished much stronger for the steel X20CrMoV 121. This difference is due to a greater stability of NbC than that of VC precipitates, both related to the evolution of the chemical composition of complex chromium, molybdenum and iron carbide particles.     

Laboratory Evaluation of Smear Zone and Correlation between Permeability and Moisture Content

In this study, the extent of the smear zone and the reduction of permeability and water content within the smear zone were investigated using a large-scale consolidometer. The installation of vertical drains by means of a mandrel causes significant disturbance of the subsoil surrounding the mandrel, resulting in a smear zone. The extent of the smear zone for Moruya clay (New South Wales, Australia) was estimated on the basis of normalized permeability and the reduction of water content by taking undisturbed samples (horizontally and vertically) at different locations. This study reveals that a significant reduction in water content and horizontal permeability takes place towards the drain, whereas the variation in the vertical permeability is negligible. The smear zone for Moruya clay was found to be 2.5 times the equivalent radius of the mandrel with the horizontal permeability varying from 1.09 to 1.64, an average of 1.34 times smaller than that of the undisturbed zone. Finally, a correlation between the permeability decrease and water content reduction within smear zone is proposed.