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101.
Advances in the research of nitrogen containing stainless steels 总被引:1,自引:0,他引:1
The current status of nitrogen containing stainless steels at home and aboard has been introduced. The function and existing forms of nitrogen in the stainless steels, influence of nitrogen on mechanical properties and anti-corrosion properties as well as the application of nitrogen containing cast stainless steels were discussed in this paper. It is clear that nitrogen will be a potential and important alloying element in stainless steels. And Argon Oxygen Decarbonization (AOD) refining can provide an advanced manufacture process for nitrogen containing stainless steels with ultra-low- carbon and high cleanliness. 相似文献
102.
T. Nguyen I. Zarudi L.C. Zhang 《International Journal of Machine Tools and Manufacture》2007,47(1):97-106
This paper studies an innovative development of a steel grinding–hardening technology using an inert cryogen—liquid nitrogen. It was found that phase transformations took place during grinding with the application of liquid nitrogen and resulted in hardened surface layer in a ground component. The layer had a fine laths martensite structure which gave rise to a remarkably high hardness. It was also shown that the treatment can produce superior surface integrity, with compressive surface residual stresses and without surface oxidation. Due to the inert nature of the liquid nitrogen, the grinding process becomes environmentally conscious. 相似文献
103.
104.
Simulation of nitrogen dynamics and biomass production in winter wheat using the Danish simulation model DAISY 总被引:14,自引:0,他引:14
S. Hansen H. E. Jensen N. E. Nielsen H. Svendsen 《Nutrient Cycling in Agroecosystems》1991,27(2-3):245-259
A dynamic simulation model for the soil plant system is described. The model includes a number of main modules, viz., a hydrological model including a submodel for soil water dynamics, a soil temperature model, a soil nitrogen model including a submodel for soil organic matter dynamics, and a crop model including a submodel for nitrogen uptake. The soil part of the model has a one-dimensional vertical structure. The soil profile is divided into layers on the basis of physical and chemical soil characteristics. The simulation model was used to simulate soil nitrogen dynamics and biomass production in winter wheat grown at two locations at various levels of nitrogen fertilization. The simulated results were compared to experimental data including concentration of inorganic nitrogen in soil, crop yield, and nitrogen accumulated in the aboveground part of the crop. Based on this validation it is concluded that the overall performance of the model is satisfactory although some minor adjustments of the model may prove to be necessary. 相似文献
105.
探讨了影响连续固相增粘产品活性的因素,提出了控制主反应器的温度、氮气流量、基础切片的端羧基、氮气露点等主要因素,实现生产的平稳控制,从而保证产品黏度的稳定。 相似文献
106.
Luis Fernando Crdoba Wolfgang M.H. Sachtler Consuelo Montes de Correa 《Applied catalysis. B, Environmental》2005,56(4):269-277
A series of sulfated zirconia supported Pd/Co catalysts was synthesized by the sol–gel method and examined for NOx reduction by methane. The NO conversion increased up to a Co/S ratio of 0.43, and then decreased at a higher Co loading (Co/S = 0.95). Sulfate content was also essential for obtaining high selectivity to molecular nitrogen. A catalyst loaded with 0.06 wt.% Pd, 2.1 wt.% Co and 2.1 wt.% S (Pd/Co-SZ-2) exhibited remarkable performance under lean conditions and displayed stability in a long-term durability test using a synthetic reaction mixture containing 10% water vapor. This catalyst exhibited the highest sulfur retention most probably as cobalt sulfide. Besides, the catalytic oxidation of NO to NOy groups was confirmed by FT-IR, in agreement with the general mechanism for the SCR of NO by hydrocarbons. In the absence of oxygen in the feed stream, the catalyst was highly active for NO reduction with methane. IR stretching bands assigned to N2O and adsorbed nitro groups were identified upon adsorbing NO on Pd/Co-SZ-2. This indicates that under rich conditions disproportionation of NO to N2O and NO2 occurs and confirms that the formation of NO2 species is an essential step for NO reduction by CH4. 相似文献
107.
甲醛法测定铵盐含氮量 总被引:6,自引:0,他引:6
对甲醛法测定铵盐含氮量进行了研究,提出采用百里酚酞和酚酞混和指示剂进行测定。该法简单、快速、准确,能满足生产实际和样品检验需要。 相似文献
108.
S. Yonemochi A. Sugiyama K. Kawamura T. Nagoya R. Aogaki 《Journal of Applied Electrochemistry》2004,34(12):1279-1285
Novel air purification materials were fabricated by the application of a magnetic field. In a magnetic field perpendicular to a copper plate, nickel particles with a diameter of 10 m were arranged to form numerous pillar-like structures on the matrix surface, and copper as a binder was deposited onto the three-dimensional surface. The total surface area of the pillars and the matrix increased with the magnetic flux density, up to about 800 cm2 per cm2 of the original matrix surface at 6.2 T. After successful codeposition of TiO2 particles on the fabricated materials by electroplating, their photocatalytic activities were evaluated on the basis of the removal efficiency of nitrogen oxides (NO
x
), which are some of the most hazardous air pollutants. It was concluded that the samples with the pillar-like structures had two opposite characteristics: large surface area as a positive effect and shadowing against ultraviolet (UV) irradiation as a negative effect. However, total photocatalytic activity increased to twice as much as that of the flat sample by improving the UV irradiation method and the preparation condition of the materials 相似文献
109.
P. Muthuswamy C. R. Ranganathan V. Murugappan P. Santhy G. Ramanathan 《Nutrient Cycling in Agroecosystems》1990,23(3):135-140
A mathematical model has been proposed for predicting the changes in soil nitrogen status due to continuous fertilization in a continuous cropping sequence. The model also enabled the prediction of the steady state of soil nitrogen for a specified fertilizer practice.The model was applied to six years nitrogen availability data of four fertilizer practices in finger millet-maize-cowpea sequence followed in the Long Term Fertilizer Experiments conducted at Tamil Nadu Agricultural University, Coimbatore, India. The agreement between the predicted soil nitrogen status by the model and the actuals was proved by employing reliability index. 相似文献
110.
Hydrotalcites in the nitrate form were prepared using microwave irradiation in the hydrotreatment step. The surface area (BET) of nitrated hydrotalcites was evaluated. Solids were characterized by atomic absorption, X-ray diffraction and BET analysis. Thermal pretreatment temperature determined the surface area of the hydrotalcites. 相似文献