Experiments were carried out by adding CaF2 and NaF as catalysts in an Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range...Experiments were carried out by adding CaF2 and NaF as catalysts in an Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range from 1 473 to 1 673 K. The scanning electron microscope (SEM) was used to characterize the microstructure of product. By analyzing reduction mechanism, it was found that the rate controlling step was gas diffusion, and the activation energy was 178.39 kJ/mol without adding any catalysts. Adding CaF2 or NaF of 3% to vanadium titano-magnetite carbon composite pellets can decrease the apparent activation energy of reduction, and the decrease extent was 14.95 and 15.79 kJ/mol, respectively. In addition, temperature was an important factor influencing on reaction rate.展开更多
Constipation is a common gastrointestinal disorder characterized by infrequentbowel movements and difficulty in passing stools.It can significantly affect anindividual's quality of life and overall well-being.Unde...Constipation is a common gastrointestinal disorder characterized by infrequentbowel movements and difficulty in passing stools.It can significantly affect anindividual's quality of life and overall well-being.Understanding the causes ofconstipation is important for its effective management and treatment.In thispaper,we have reviewed the primary causes of constipation or functional constipation.Primary constipation is a bowel disorder associated with colonic oranorectal sensorimotor or neuromuscular dysfunction.As per the literature,it ismultifactorial and involves factors such as decreased interstitial cells of Cajal,altered colonic motility,enteric nervous system dysfunction,intestinal flora disturbances,and psychological influences.Clinical symptoms include difficulty indefecation,decreased frequency of defecation,or a feeling of incomplete evacuation.A comprehensive evaluation and management of constipation require aninterdisciplinary approach incorporating dietary modifications,lifestyle changes,pharmacotherapy,and psychological interventions.Further research is imperativeto explain the intricate mechanisms underlying constipation and develop targetedtherapies for improved patient outcomes.展开更多
镍基合金是一种在高温下具有良好耐腐蚀性及相当高强度的合金,在其成分分析中,存在样品难溶、分析测定不准等困难。研究比较了在不同混酸种类和配比条件下,采用传统湿法消解和现代微波消解2种溶样方式处理样品的不同。试验发现,采用HCl-...镍基合金是一种在高温下具有良好耐腐蚀性及相当高强度的合金,在其成分分析中,存在样品难溶、分析测定不准等困难。研究比较了在不同混酸种类和配比条件下,采用传统湿法消解和现代微波消解2种溶样方式处理样品的不同。试验发现,采用HCl-HNO_(3)(10∶1)(体积比,下同)可将难溶镍基合金样品消解澄清,替代使用强腐蚀性HF作为助溶剂的消解方法。同时,考察了以Ni(60%)、Cr(22%)(质量分数,下同)为基体制作工作曲线对测定Co、Fe、Mn、Ti等元素的影响。结果表明,用少量HCl-HNO_(3)(10∶1)混酸为溶剂,采用微波消解处理样品时酸消耗量小、消解用时短、测定结果准确。用多元素混合标准系列溶液制作工作曲线,测定结果扣除镍铬基体空白后,与Inconel标准物质BS 625E(UNS Number N06625)认证值对比,相对误差在-10.6129%~8.7097%范围内,相对标准偏差为0.0629%~5.6864%。该法可准确测定难溶镍基合金中质量分数范围为0.001%~5%的Co、Fe、Mn、Ti等元素。研究结果可为冶金企业技术检测部门消解难溶镍基合金、测定合金中Co、Fe、Mn、Ti等元素提供可行的方法。展开更多
In order to effectively recycle resource for the benefit of the global environment, the utilization of waste plastics as auxiliary injectant for blast furnaces is becoming increasingly important. Combustion kinetics o...In order to effectively recycle resource for the benefit of the global environment, the utilization of waste plastics as auxiliary injectant for blast furnaces is becoming increasingly important. Combustion kinetics of plastics-coal blends with 0, 10%, 20% and 40% waste plastics (WP) are investigated separately by thermogravimetric analysis (TGA) from ambient temperature to 900 ℃ in air atmosphere. These blends are combusted at the heating rates of 5, 10 and 20 ℃/min. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages and three stages. The waste plastics content and heating rates have important effects on the main combustion processes of blends. With the increase of waste plastics content, the ignition temperature and the final combustion temperature of blends tend to decrease, while the combustion reaction becomes fiercer. With the increase of the heating rate, the ignition temperature, the mass loss rate of the peaks and the final combustion temperature of blends combustion tend to increase. The Flynn-Wall-Ozawa (FWO) iso-conversional method is used for the kinetic analysis of the main combustion process. The results indicate that, when the waste plastics content varied from 0 to 40%, the values of activation energy increase from 126.05 to 184.12 kJ /mol.展开更多
During the transient process of gas drilling conditions,the monitoring data often has obvious nonlinear fluctuation features,which leads to large classification errors and time delays in the commonly used intelligent ...During the transient process of gas drilling conditions,the monitoring data often has obvious nonlinear fluctuation features,which leads to large classification errors and time delays in the commonly used intelligent classification models.Combined with the structural features of data samples obtained from monitoring while drilling,this paper uses convolution algorithm to extract the correlation features of multiple monitoring while drilling parameters changing with time,and applies RBF network with nonlinear classification ability to classify the features.In the training process,the loss function component based on distance mean square error is used to effectively adjust the best clustering center in RBF.Many field applications show that,the recognition accuracy of the above nonlinear classification network model for gas production,water production and drill sticking is 97.32%,95.25%and 93.78%.Compared with the traditional convolutional neural network(CNN)model,the network structure not only improves the classification accuracy of conditions in the transition stage of conditions,but also greatly advances the time points of risk identification,especially for the three common risk identification points of gas production,water production and drill sticking,which are advanced by 56,16 and 8 s.It has won valuable time for the site to take correct risk disposal measures in time,and fully demonstrated the applicability of nonlinear classification neural network in oil and gas field exploration and development.展开更多
基金Item Sponsored by National Key Technology Research and Development Program of China(2008BAB32B05)
文摘Experiments were carried out by adding CaF2 and NaF as catalysts in an Ar atmosphere to study the isothermal reduction kinetics of vanadium titano-magnetite carbon composite pellets under high temperature in the range from 1 473 to 1 673 K. The scanning electron microscope (SEM) was used to characterize the microstructure of product. By analyzing reduction mechanism, it was found that the rate controlling step was gas diffusion, and the activation energy was 178.39 kJ/mol without adding any catalysts. Adding CaF2 or NaF of 3% to vanadium titano-magnetite carbon composite pellets can decrease the apparent activation energy of reduction, and the decrease extent was 14.95 and 15.79 kJ/mol, respectively. In addition, temperature was an important factor influencing on reaction rate.
文摘Constipation is a common gastrointestinal disorder characterized by infrequentbowel movements and difficulty in passing stools.It can significantly affect anindividual's quality of life and overall well-being.Understanding the causes ofconstipation is important for its effective management and treatment.In thispaper,we have reviewed the primary causes of constipation or functional constipation.Primary constipation is a bowel disorder associated with colonic oranorectal sensorimotor or neuromuscular dysfunction.As per the literature,it ismultifactorial and involves factors such as decreased interstitial cells of Cajal,altered colonic motility,enteric nervous system dysfunction,intestinal flora disturbances,and psychological influences.Clinical symptoms include difficulty indefecation,decreased frequency of defecation,or a feeling of incomplete evacuation.A comprehensive evaluation and management of constipation require aninterdisciplinary approach incorporating dietary modifications,lifestyle changes,pharmacotherapy,and psychological interventions.Further research is imperativeto explain the intricate mechanisms underlying constipation and develop targetedtherapies for improved patient outcomes.
文摘镍基合金是一种在高温下具有良好耐腐蚀性及相当高强度的合金,在其成分分析中,存在样品难溶、分析测定不准等困难。研究比较了在不同混酸种类和配比条件下,采用传统湿法消解和现代微波消解2种溶样方式处理样品的不同。试验发现,采用HCl-HNO_(3)(10∶1)(体积比,下同)可将难溶镍基合金样品消解澄清,替代使用强腐蚀性HF作为助溶剂的消解方法。同时,考察了以Ni(60%)、Cr(22%)(质量分数,下同)为基体制作工作曲线对测定Co、Fe、Mn、Ti等元素的影响。结果表明,用少量HCl-HNO_(3)(10∶1)混酸为溶剂,采用微波消解处理样品时酸消耗量小、消解用时短、测定结果准确。用多元素混合标准系列溶液制作工作曲线,测定结果扣除镍铬基体空白后,与Inconel标准物质BS 625E(UNS Number N06625)认证值对比,相对误差在-10.6129%~8.7097%范围内,相对标准偏差为0.0629%~5.6864%。该法可准确测定难溶镍基合金中质量分数范围为0.001%~5%的Co、Fe、Mn、Ti等元素。研究结果可为冶金企业技术检测部门消解难溶镍基合金、测定合金中Co、Fe、Mn、Ti等元素提供可行的方法。
基金Item Sponsored by National Key Technology Research and Development Program in 11th Five-Year Plan of China (2008BAB32B05)
文摘In order to effectively recycle resource for the benefit of the global environment, the utilization of waste plastics as auxiliary injectant for blast furnaces is becoming increasingly important. Combustion kinetics of plastics-coal blends with 0, 10%, 20% and 40% waste plastics (WP) are investigated separately by thermogravimetric analysis (TGA) from ambient temperature to 900 ℃ in air atmosphere. These blends are combusted at the heating rates of 5, 10 and 20 ℃/min. The results indicate that, with the increase of waste plastics content, the combustion processes of blends could be divided into one stage, two stages and three stages. The waste plastics content and heating rates have important effects on the main combustion processes of blends. With the increase of waste plastics content, the ignition temperature and the final combustion temperature of blends tend to decrease, while the combustion reaction becomes fiercer. With the increase of the heating rate, the ignition temperature, the mass loss rate of the peaks and the final combustion temperature of blends combustion tend to increase. The Flynn-Wall-Ozawa (FWO) iso-conversional method is used for the kinetic analysis of the main combustion process. The results indicate that, when the waste plastics content varied from 0 to 40%, the values of activation energy increase from 126.05 to 184.12 kJ /mol.
基金supported by the National Key R&D Program of China(2019YFA0708303)the Sichuan Science and Technology Program(2021YFG0318)+2 种基金the Engineering Technology Joint Research Institute Project of CCDC-SWPU(CQXN-2021-03)the PetroChina Innovation Foundation(2020D-5007-0312)the Key projects of NSFC(61731016).
文摘During the transient process of gas drilling conditions,the monitoring data often has obvious nonlinear fluctuation features,which leads to large classification errors and time delays in the commonly used intelligent classification models.Combined with the structural features of data samples obtained from monitoring while drilling,this paper uses convolution algorithm to extract the correlation features of multiple monitoring while drilling parameters changing with time,and applies RBF network with nonlinear classification ability to classify the features.In the training process,the loss function component based on distance mean square error is used to effectively adjust the best clustering center in RBF.Many field applications show that,the recognition accuracy of the above nonlinear classification network model for gas production,water production and drill sticking is 97.32%,95.25%and 93.78%.Compared with the traditional convolutional neural network(CNN)model,the network structure not only improves the classification accuracy of conditions in the transition stage of conditions,but also greatly advances the time points of risk identification,especially for the three common risk identification points of gas production,water production and drill sticking,which are advanced by 56,16 and 8 s.It has won valuable time for the site to take correct risk disposal measures in time,and fully demonstrated the applicability of nonlinear classification neural network in oil and gas field exploration and development.