The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from ...The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from yellow to dark green with increasing the h-BN addition. Fourier-transform infrared （FTIR） results indicate that sp2 hybridization B-N-B and B-N structures generate when the additive content reaches a certain value in the system. The two peaks are located at 745 and 1425cm-1, respectively. Fhrthermore, the FTIR characteristic peak resulting from nitrogen pairs is noticed and it tends to vanish when the h-BN addition reaches 1.1 wt%. Furthermore, Raman peak of the synthesized diamond shifts down to a lower wavenumber with increasing the h-BN ~ddition content in the synthesis system.展开更多
The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth （TGG） under high pressure and high temperature （HPHT） conditions with using a Ni-based...The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth （TGG） under high pressure and high temperature （HPHT） conditions with using a Ni-based catalyst in this article. The experimental results show that the morphology of diamond changes from an octahedral shape to a cub- octahedral shape as the catalyst height rises. Moreover, the finite element method （FEM） is used to simulate the temperature field of the melted catalyst/solvent. The results show that the temperature at the location of the seed diamond continues to decrease with the increase of catalyst height, which is conducive to changing the morphology of diamond. This work provides a new way to change the diamond crystal morphology.展开更多
In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435&...In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435°C by temperature gradient growth. The effects of Fe additive on the crystal morphology are discussed in the diamond crystallization process.Furthermore, Fourier infrared measurement results indicate that the spectrum of the diamond obtained from Ni + Fe–C system after annealing treatment is nearly consistent with that of natural diamond crystal. We believe that this study is of benefit to a further understanding of the growth mechanism of natural diamond.展开更多
In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, ...In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, but also the sintered temperature is lower under high pressure and high temperature than those of under normal pressure. It is thought that the adscititious pressure plays the key role in this process, which is discussed in detail. The composition and the structure of the as-prepared samples are recorded by XRD patterns. The result shows that the phases of Ba TiO3, BaBiO（2.77）, and Ba2Bi4Ti5O（18） with piezoelectric ceramic performance generate in the sintered samples. Furthermore, the surface morphology characteristics of the typical samples are also investigated using a scanning electron microscope. It indicates that the grain size and surface structure of the samples are closely related to the sintering temperature and sintering time. It is hoped that this study can provide a new train of thought for the preparation of lead-free piezoelectric ceramics with excellent performance.展开更多
In this paper,generalized wavelet-neural network(WNN)based models were developed for estimating reference evapotranspiration(ETo)corresponding to Hargreaves(HG)method for different agro-ecological regions(AERs):semi-a...In this paper,generalized wavelet-neural network(WNN)based models were developed for estimating reference evapotranspiration(ETo)corresponding to Hargreaves(HG)method for different agro-ecological regions(AERs):semi-arid,arid,sub-humid,and humid in India.The input and target to the WNN models are climate data(minimum and maximum air temperature)and ETo(estimated from FAO-56 Penman Monteith method),respectively.The developed WNN models were compared with the various generalized conventional models such as artificial neural networks(ANN),linear regression(LR),wavelet regression(WR),and HG method to test the best performed model.The performance indices used for the comparison include root mean squared error(RMSE),Nash-Sutcliffe efficiency(NSE),the ratio of average output to the average target ETo values(Rratio),and relative percentage(RP).The WNN and ANN models were performed better as compared to LR,WR and HG methods.Further,the best performed WNN and ANN models were tested on locations,which were not included in training to test their generalizing capability.It is concluded that the WNN and ANN models were shown good generalizing capability for the tested locations as compared to HG method.展开更多
The ageing of the Algerian oil and gas(O&G)installations has led to many incidents.Such installations are over 30 years old(life cycle)and still in operation.To deal with this O&G crucial problem,the Algerian ...The ageing of the Algerian oil and gas(O&G)installations has led to many incidents.Such installations are over 30 years old(life cycle)and still in operation.To deal with this O&G crucial problem,the Algerian authorities have launched a rehabilitation and modernization schedule of these installations.Within the framework of this program,many audit operations are initiated to elaborate a general diagnosis of the works to be performed while optimizing production.In other words,industrial ageing risks shall be controlled.In the process safety management(PSM)context,the aim of this paper is to study ageing problem of the Algerian industrial installations through proposed indicators.Their prioritization adjusted by(TOPSIS)Technique for Order-Preference by Similarity to Ideal Solution method which allows identification of ageing control solutions of Algerian onshore fields.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 51172089the Natural Science Foundation of Guizhou Province Education Department under Grant No KY[2013]183the Natural Science Foundation of Guizhou Province Science and Technology Agency under Grant Nos LH[2015]7232 and LH[2015]7228
文摘The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from yellow to dark green with increasing the h-BN addition. Fourier-transform infrared （FTIR） results indicate that sp2 hybridization B-N-B and B-N structures generate when the additive content reaches a certain value in the system. The two peaks are located at 745 and 1425cm-1, respectively. Fhrthermore, the FTIR characteristic peak resulting from nitrogen pairs is noticed and it tends to vanish when the h-BN addition reaches 1.1 wt%. Furthermore, Raman peak of the synthesized diamond shifts down to a lower wavenumber with increasing the h-BN ~ddition content in the synthesis system.
基金supported by the National Natural Science Foundation of China(Grant No.51172089)the Program for New Century Excellent Talents in University,the Natural Science Foundation of Guizhou Provincial Education Department(Grant No.KY[2013]183)the Collaborative Fund of Science and Technology Office of Guizhou Province,China(Grant No.LH[2015]7232)
文摘The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth （TGG） under high pressure and high temperature （HPHT） conditions with using a Ni-based catalyst in this article. The experimental results show that the morphology of diamond changes from an octahedral shape to a cub- octahedral shape as the catalyst height rises. Moreover, the finite element method （FEM） is used to simulate the temperature field of the melted catalyst/solvent. The results show that the temperature at the location of the seed diamond continues to decrease with the increase of catalyst height, which is conducive to changing the morphology of diamond. This work provides a new way to change the diamond crystal morphology.
基金supported by the National Natural Science Foundation of China(Grant No.51172089)the Natural Science Foundation of Guizhou Provincial Education Department,China(Grant No.KY[2013]183)the Research Fund for the Doctoral Program of Tongren University,China(Grant Nos.DS1302 and trxy S1415)
文摘In this paper, diamond crystallization from carbonyl nickel powders-C and carbonyl nickel powders + Fe–C systems are investigated in detail at a pressure of 6.0 GPa and temperatures ranging from 1410°C–to 1435°C by temperature gradient growth. The effects of Fe additive on the crystal morphology are discussed in the diamond crystallization process.Furthermore, Fourier infrared measurement results indicate that the spectrum of the diamond obtained from Ni + Fe–C system after annealing treatment is nearly consistent with that of natural diamond crystal. We believe that this study is of benefit to a further understanding of the growth mechanism of natural diamond.
基金Project supported by the National Natural Science Foundation of China(Grant No.51172089)the Natural Science Foundation of Education Department of Guizhou Province,China(Grant Nos.KY[2013]183 and LH[2015]7232)the Research Fund for the Doctoral Program of Tongren University,China(Grant No.DS1302)
文摘In this paper, the preparation of 0.08BiGaO3–0.90BaTiO3–0.02LiNbO3 is investigated at pressure 3.8 GPa and temperature 1100–1200？C. Experimental results indicate that not only is the sintered rate more effective, but also the sintered temperature is lower under high pressure and high temperature than those of under normal pressure. It is thought that the adscititious pressure plays the key role in this process, which is discussed in detail. The composition and the structure of the as-prepared samples are recorded by XRD patterns. The result shows that the phases of Ba TiO3, BaBiO（2.77）, and Ba2Bi4Ti5O（18） with piezoelectric ceramic performance generate in the sintered samples. Furthermore, the surface morphology characteristics of the typical samples are also investigated using a scanning electron microscope. It indicates that the grain size and surface structure of the samples are closely related to the sintering temperature and sintering time. It is hoped that this study can provide a new train of thought for the preparation of lead-free piezoelectric ceramics with excellent performance.
文摘In this paper,generalized wavelet-neural network(WNN)based models were developed for estimating reference evapotranspiration(ETo)corresponding to Hargreaves(HG)method for different agro-ecological regions(AERs):semi-arid,arid,sub-humid,and humid in India.The input and target to the WNN models are climate data(minimum and maximum air temperature)and ETo(estimated from FAO-56 Penman Monteith method),respectively.The developed WNN models were compared with the various generalized conventional models such as artificial neural networks(ANN),linear regression(LR),wavelet regression(WR),and HG method to test the best performed model.The performance indices used for the comparison include root mean squared error(RMSE),Nash-Sutcliffe efficiency(NSE),the ratio of average output to the average target ETo values(Rratio),and relative percentage(RP).The WNN and ANN models were performed better as compared to LR,WR and HG methods.Further,the best performed WNN and ANN models were tested on locations,which were not included in training to test their generalizing capability.It is concluded that the WNN and ANN models were shown good generalizing capability for the tested locations as compared to HG method.
文摘The ageing of the Algerian oil and gas(O&G)installations has led to many incidents.Such installations are over 30 years old(life cycle)and still in operation.To deal with this O&G crucial problem,the Algerian authorities have launched a rehabilitation and modernization schedule of these installations.Within the framework of this program,many audit operations are initiated to elaborate a general diagnosis of the works to be performed while optimizing production.In other words,industrial ageing risks shall be controlled.In the process safety management(PSM)context,the aim of this paper is to study ageing problem of the Algerian industrial installations through proposed indicators.Their prioritization adjusted by(TOPSIS)Technique for Order-Preference by Similarity to Ideal Solution method which allows identification of ageing control solutions of Algerian onshore fields.
