Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has develop...Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has developed a fin-less control technology called Stagnation Pressure Reaction Control(SPRC)that takes stagnation pressure air and directs it sideways to control non-spinning projectiles.In a previous study,this technology was demonstrated at Mach 2 wind-tunnel conditions to achieve up to 1.5°controllable angle of incidence for a non-spinning,aerodynamically unstable projectile-like test object.In an operational scenario,the decelerating projectile will experience a decline in control force while the simultaneous forward shift of the center of pressure increases the need for control force.Furthermore,angles of incidence exceeding 1.5°will be experienced under realistic flight conditions,especially against maneuvering targets.This work addresses these challenges and presents an operational feasibility study for a practical application of SPRC in a non-spinning mid-caliber gun-launched projectile,using experiment data on control latency and force of the earlier study.It illustrates the combined effect of the control-and stability dynamics and underlines the potential of an SPRC projectile as a precisionoperation ammunition.This research revealed that SPRC technology can stabilize and control the hypothesized projectile in a direct fire scenario against stationary and maneuvering targets.展开更多
The energy industry faces a significant challenge in extracting natural gas from offshore natural gas hydrate(NGH)reservoirs,primarily due to the low productivity of wells and the high operational costs involved.The p...The energy industry faces a significant challenge in extracting natural gas from offshore natural gas hydrate(NGH)reservoirs,primarily due to the low productivity of wells and the high operational costs involved.The present study offers an assessment of the feasibility of utilizing geothermal energy to augment the production of natural gas from offshore gas hydrate reservoirs through the implementation of the methane-CO_(2)swapping technique.The present study expands the research scope of the authors beyond their previous publication,which exclusively examined the generation of methane from marine gas hydrates.Specifically,the current investigation explores the feasibility of utilizing the void spaces created by the extracted methane in the hydrate reservoir for carbon dioxide storage.Analytical models were employed to forecast the heat transfer from a geothermal zone to an NGH reservoir.A study was conducted utilizing data obtained from a reservoir situated in the Shenhu region of the Northern South China Sea.The findings of the model indicate that the implementation of geothermal heating can lead to a substantial enhancement in the productivity of wells located in heated reservoirs during CO_(2)swapping procedures.The non-linear relationship between the temperature of the heated reservoir and the rate of fold increase has been observed.It is anticipated that the fold of increase will surpass 5 when the gas hydrate reservoir undergoes a temperature rise from 6℃ to 16℃.The mathematical models utilized in this study did not incorporate the impact of heat convection resulting from CO_(2)flow into the gas reservoir.This factor has the potential to enhance well productivity.The mathematical models’deviation assumptions may cause over-prediction of well productivity in geothermal-stimulated reservoirs.Additional research is required to examine the impacts of temperature drawdown,heat convection resulting from depressurization,heat-induced gas pressure increment,and the presence of free gas in the formation containing hydrates.The process of CH4-CO_(2)swapping,which has been investigated,involves the utilization of geothermal stimulation.This method is highly encouraging as it enables the efficient injection of CO_(2)into gas hydrate reservoirs,resulting in the permanent sequestration of CO_(2)in a solid state.Additional research is warranted to examine the rate of mass transfer of CO_(2)within reservoirs of gas hydrates.展开更多
Jinchuan nickel mine is the largest nickel mine in China. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. T...Jinchuan nickel mine is the largest nickel mine in China. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. The first step stopped the mining rooms and the second step stopped the pillars. Because the two-step method made big trouble for finally mining pillars and strongly limited the mining speed and production, it was successfully changed to a continuous cut-and-fill method without pillars. Howerver, the mining operation in the mine has been down to 800 m and the mining condition is getting worse and more complicated. Through systematical field investigations and 3-D FEM analysis, it is proved that the mining method without pillars is feasible for mining deeper orebodies in Jinchuan nickel mine.展开更多
The Toroidal Field (TF) coil case of the HT-7U superconducting tokamak device is made of austenitic stainless steel 316LN and is designed to operate at cryogenic temperature (4 K). 316LN can retain high strength and f...The Toroidal Field (TF) coil case of the HT-7U superconducting tokamak device is made of austenitic stainless steel 316LN and is designed to operate at cryogenic temperature (4 K). 316LN can retain high strength and fracture toughness at 4 K. Feasibility study on technical process of welding has been experimentally considered as a hopeful joint method for suppression of post-welding deformation and reduction of over-heating. Meanwhile the final range of stress intensity and the stress intensity factor (K) for pre-cracks of welding structure have been determined by using J-integral. These related results are optimistic and have shown that there’s no problem in strength and fracture toughness at the vicinity of the pre-crack tip. This paper introduces the welding structure of TF coil case in detail.展开更多
Renewable energy, particularly solar energy, offers a clean and alternative energy source to meet the energy demand for sustainable development in the world. Due to its profitability and viability, PV net-metering sch...Renewable energy, particularly solar energy, offers a clean and alternative energy source to meet the energy demand for sustainable development in the world. Due to its profitability and viability, PV net-metering scheme has been adopted in many countries. The feasibility of implementation PV rooftop system with net metering in residential, commercial, governmental and industrial sectors in Iraq is demonstrated in this study. A financial model has been developed to investigate the feasibility parameters <i>NPV</i>, <i>IRR</i> and annual savings of 24 kWp PV system. The results showed that increasing the capacity of the PV system in residential and commercial buildings will lead to a profitable investment return and the breakeven point that may make the PV net-metering projects feasible is very close to the tariff applied for the commercial sector (10.29 $c/kWh). In the governmental sector, the tariff needs to </span><span style="font-family:Verdana;">increase by 35.1% to reach breakeven. However, for such net-metering scheme</span><span style="font-family:Verdana;"> to be attractive and feasible on a wide scale, it is crucial to back it with financial support through soft loans and grants.展开更多
It has been proved that traditional public English teaching can‘t meet the society requirements for the high skilled talent-ed,while Career English teaching can help students connect English learning with their futur...It has been proved that traditional public English teaching can‘t meet the society requirements for the high skilled talent-ed,while Career English teaching can help students connect English learning with their future career,which better reflects occupa-tional and practical characteristics of higher vocational education.The paper puts forwards three feasibilities in Career Englishteaching reform in order to promote teaching quality of public English teaching in higher vocational colleges further.展开更多
The differential pricing for peak hours encourages industrial consumers to look for independent power supplies for the period from 19 to 22 hours. This paper presents a study to identify the optimal solution for a rec...The differential pricing for peak hours encourages industrial consumers to look for independent power supplies for the period from 19 to 22 hours. This paper presents a study to identify the optimal solution for a recycled paper mill that also intends to work in that period. The factory is located in Rio Grande do Sul, in southern Brazil, and considers the use of a diesel gen set, a micro hydro power plant and possibly PV modules. Two micro hydro power plants were considered in the study, an old plant to be renewed and another to be fully implemented. The software Homer was used as a tool to determine the most feasible combination of components considered in the study. The sale of surplus power to the energy system appears as a key to viability of alternatives that are not based solely on diesel generators. The optimal solution consists of a combination of diesel generators and micro hydro power plant, in one case, and only on hydroelectric power plant in another, with a significant penetration of PV modules if its cost is reduced to 12% of the current price, selling an amount of energy equal to that which is bought. The annual water availability in one of the sites requires diesel supplement, while the other, more abundant, this supplement is not necessary.展开更多
In the field of large-capacity accelerator construction, there are two world-wide trends now evident in high-energy physicists: one is to build up high-energy ones such as the LHC (Large Hadron Collider) developed by ...In the field of large-capacity accelerator construction, there are two world-wide trends now evident in high-energy physicists: one is to build up high-energy ones such as the LHC (Large Hadron Collider) developed by Conseil Européen pour la Recherches Nucleaires (CERN) and the other features high precision, including β-factories in the US and Japan and the φ-factory and τ-factory展开更多
The feasibility study of the Beijing Tau-Charm Factory(BTCF), approved by the Chinese government to have been completing from February of 1995 to the end of 1996, has been carried out successfully by the Institute of ...The feasibility study of the Beijing Tau-Charm Factory(BTCF), approved by the Chinese government to have been completing from February of 1995 to the end of 1996, has been carried out successfully by the Institute of High-Energy Physics (IHEP) under the CAS.Also this is a cooperative project shared by seven Chinese institutions of Peking University,the CAS Institute of Theoretical Physics,Nanjing University,Shandong University,Shanghai Jiaotong University, Qinghua University and the CAS-affiliated University of S&T of China. The main tasks of this study are:展开更多
The implementation of general education is the only way to train higher vocational complex talents.Through analysis ofthe feasibility of developing general education in public English courses of higher vocational coll...The implementation of general education is the only way to train higher vocational complex talents.Through analysis ofthe feasibility of developing general education in public English courses of higher vocational colleges,it is hoped that the reform ofpublic English will be promoted effectively.展开更多
The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the...The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided.展开更多
Based on the present situation and problems concerning ginseng cultivation as well as soilless cultivation features,we analyze the growth indicators and input-output ratio of different ginseng cultivation patterns,and...Based on the present situation and problems concerning ginseng cultivation as well as soilless cultivation features,we analyze the growth indicators and input-output ratio of different ginseng cultivation patterns,and conform that the soilless cultivation technology for organic ginseng is feasible. And this technology provides theoretical basis and technological feasibility for the sustainable development of ginseng industry.展开更多
The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirem...The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirements of 6G can be achieved,it is essential to establish a set of key performance indicators(KPIs).This paper comprehensively assesses the KPIs not only from the service requirements but also from the technical feasibility points of view.Specifically,theoretical derivations of KPIs have been clarified,and numerical evaluations have been conducted with reasonable technical assumptions.Evaluation results show that some KPIs defined from the service requirements can be improved through advanced technologies while some are still challenging for practical implementations,such as Tbps-level peak data rate and 0.1 ms user plane latency.In addition,it is also necessary to comply with multiple KPIs for some cases.Furthermore,based on the technical analysis,the potential enabling technologies are outlined and foreseeable implementation challenges as well as possible solutions are presented,which promotes a more reasonable design for 6G mobile network.展开更多
Bioleaching of chalcopyrite often encountered the formation of passivation layer,which inhibited the leaching process and resulted in a low leaching rate.This inhibitory effect can be eliminated by thermophilic biolea...Bioleaching of chalcopyrite often encountered the formation of passivation layer,which inhibited the leaching process and resulted in a low leaching rate.This inhibitory effect can be eliminated by thermophilic bioleaching.The industrial test of BioCOP technology based on thermophiles was successfully completed,which confirmed the feasibility of chalcopyrite bioleaching.However,industrial leaching rate of chalcopyrite heap bioleaching is lower.This paper described the development status and industrial test of chalcopyrite heap bioleaching technology.The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed.The strategies for successful chalcopyrite heap bioleaching were proposed.展开更多
文摘Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has developed a fin-less control technology called Stagnation Pressure Reaction Control(SPRC)that takes stagnation pressure air and directs it sideways to control non-spinning projectiles.In a previous study,this technology was demonstrated at Mach 2 wind-tunnel conditions to achieve up to 1.5°controllable angle of incidence for a non-spinning,aerodynamically unstable projectile-like test object.In an operational scenario,the decelerating projectile will experience a decline in control force while the simultaneous forward shift of the center of pressure increases the need for control force.Furthermore,angles of incidence exceeding 1.5°will be experienced under realistic flight conditions,especially against maneuvering targets.This work addresses these challenges and presents an operational feasibility study for a practical application of SPRC in a non-spinning mid-caliber gun-launched projectile,using experiment data on control latency and force of the earlier study.It illustrates the combined effect of the control-and stability dynamics and underlines the potential of an SPRC projectile as a precisionoperation ammunition.This research revealed that SPRC technology can stabilize and control the hypothesized projectile in a direct fire scenario against stationary and maneuvering targets.
基金funding the project“Safe,Sustainable,and Resilient Development of Offshore Reservoirs and Natural Gas Upgrading through Innovative Science and Technology:Gulf of Mexico–Mediterranean,”through Contract No.EC-19 Fossil Energy。
文摘The energy industry faces a significant challenge in extracting natural gas from offshore natural gas hydrate(NGH)reservoirs,primarily due to the low productivity of wells and the high operational costs involved.The present study offers an assessment of the feasibility of utilizing geothermal energy to augment the production of natural gas from offshore gas hydrate reservoirs through the implementation of the methane-CO_(2)swapping technique.The present study expands the research scope of the authors beyond their previous publication,which exclusively examined the generation of methane from marine gas hydrates.Specifically,the current investigation explores the feasibility of utilizing the void spaces created by the extracted methane in the hydrate reservoir for carbon dioxide storage.Analytical models were employed to forecast the heat transfer from a geothermal zone to an NGH reservoir.A study was conducted utilizing data obtained from a reservoir situated in the Shenhu region of the Northern South China Sea.The findings of the model indicate that the implementation of geothermal heating can lead to a substantial enhancement in the productivity of wells located in heated reservoirs during CO_(2)swapping procedures.The non-linear relationship between the temperature of the heated reservoir and the rate of fold increase has been observed.It is anticipated that the fold of increase will surpass 5 when the gas hydrate reservoir undergoes a temperature rise from 6℃ to 16℃.The mathematical models utilized in this study did not incorporate the impact of heat convection resulting from CO_(2)flow into the gas reservoir.This factor has the potential to enhance well productivity.The mathematical models’deviation assumptions may cause over-prediction of well productivity in geothermal-stimulated reservoirs.Additional research is required to examine the impacts of temperature drawdown,heat convection resulting from depressurization,heat-induced gas pressure increment,and the presence of free gas in the formation containing hydrates.The process of CH4-CO_(2)swapping,which has been investigated,involves the utilization of geothermal stimulation.This method is highly encouraging as it enables the efficient injection of CO_(2)into gas hydrate reservoirs,resulting in the permanent sequestration of CO_(2)in a solid state.Additional research is warranted to examine the rate of mass transfer of CO_(2)within reservoirs of gas hydrates.
文摘Jinchuan nickel mine is the largest nickel mine in China. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. The first step stopped the mining rooms and the second step stopped the pillars. Because the two-step method made big trouble for finally mining pillars and strongly limited the mining speed and production, it was successfully changed to a continuous cut-and-fill method without pillars. Howerver, the mining operation in the mine has been down to 800 m and the mining condition is getting worse and more complicated. Through systematical field investigations and 3-D FEM analysis, it is proved that the mining method without pillars is feasible for mining deeper orebodies in Jinchuan nickel mine.
文摘The Toroidal Field (TF) coil case of the HT-7U superconducting tokamak device is made of austenitic stainless steel 316LN and is designed to operate at cryogenic temperature (4 K). 316LN can retain high strength and fracture toughness at 4 K. Feasibility study on technical process of welding has been experimentally considered as a hopeful joint method for suppression of post-welding deformation and reduction of over-heating. Meanwhile the final range of stress intensity and the stress intensity factor (K) for pre-cracks of welding structure have been determined by using J-integral. These related results are optimistic and have shown that there’s no problem in strength and fracture toughness at the vicinity of the pre-crack tip. This paper introduces the welding structure of TF coil case in detail.
文摘Renewable energy, particularly solar energy, offers a clean and alternative energy source to meet the energy demand for sustainable development in the world. Due to its profitability and viability, PV net-metering scheme has been adopted in many countries. The feasibility of implementation PV rooftop system with net metering in residential, commercial, governmental and industrial sectors in Iraq is demonstrated in this study. A financial model has been developed to investigate the feasibility parameters <i>NPV</i>, <i>IRR</i> and annual savings of 24 kWp PV system. The results showed that increasing the capacity of the PV system in residential and commercial buildings will lead to a profitable investment return and the breakeven point that may make the PV net-metering projects feasible is very close to the tariff applied for the commercial sector (10.29 $c/kWh). In the governmental sector, the tariff needs to </span><span style="font-family:Verdana;">increase by 35.1% to reach breakeven. However, for such net-metering scheme</span><span style="font-family:Verdana;"> to be attractive and feasible on a wide scale, it is crucial to back it with financial support through soft loans and grants.
文摘It has been proved that traditional public English teaching can‘t meet the society requirements for the high skilled talent-ed,while Career English teaching can help students connect English learning with their future career,which better reflects occupa-tional and practical characteristics of higher vocational education.The paper puts forwards three feasibilities in Career Englishteaching reform in order to promote teaching quality of public English teaching in higher vocational colleges further.
文摘The differential pricing for peak hours encourages industrial consumers to look for independent power supplies for the period from 19 to 22 hours. This paper presents a study to identify the optimal solution for a recycled paper mill that also intends to work in that period. The factory is located in Rio Grande do Sul, in southern Brazil, and considers the use of a diesel gen set, a micro hydro power plant and possibly PV modules. Two micro hydro power plants were considered in the study, an old plant to be renewed and another to be fully implemented. The software Homer was used as a tool to determine the most feasible combination of components considered in the study. The sale of surplus power to the energy system appears as a key to viability of alternatives that are not based solely on diesel generators. The optimal solution consists of a combination of diesel generators and micro hydro power plant, in one case, and only on hydroelectric power plant in another, with a significant penetration of PV modules if its cost is reduced to 12% of the current price, selling an amount of energy equal to that which is bought. The annual water availability in one of the sites requires diesel supplement, while the other, more abundant, this supplement is not necessary.
文摘In the field of large-capacity accelerator construction, there are two world-wide trends now evident in high-energy physicists: one is to build up high-energy ones such as the LHC (Large Hadron Collider) developed by Conseil Européen pour la Recherches Nucleaires (CERN) and the other features high precision, including β-factories in the US and Japan and the φ-factory and τ-factory
文摘The feasibility study of the Beijing Tau-Charm Factory(BTCF), approved by the Chinese government to have been completing from February of 1995 to the end of 1996, has been carried out successfully by the Institute of High-Energy Physics (IHEP) under the CAS.Also this is a cooperative project shared by seven Chinese institutions of Peking University,the CAS Institute of Theoretical Physics,Nanjing University,Shandong University,Shanghai Jiaotong University, Qinghua University and the CAS-affiliated University of S&T of China. The main tasks of this study are:
文摘The implementation of general education is the only way to train higher vocational complex talents.Through analysis ofthe feasibility of developing general education in public English courses of higher vocational colleges,it is hoped that the reform ofpublic English will be promoted effectively.
文摘The Taihang Mountains area is an area in North China where serious mudflow hazards take place frequently. The hazards often obstrust traffic and make it difficult to carry out conventional ground investigations of the mudflow hazards. This paper introduces the feasibility study of mudflow hazards by using Landsat-5TM data. The study has achieved a great success through adopting both the faint spectral enhancement technique for mudflow fans (or other depositional areas) and comprehensive study of the environmental background of pregnant mudflows. Thus, remote sensing as a fast, convenient, low-cost and effective technical method can be used to recognise the situation of mudflow hazards so that effective rescue can be provided.
基金Supported by Yanbian Science and Technology Development Program(2013BC19)
文摘Based on the present situation and problems concerning ginseng cultivation as well as soilless cultivation features,we analyze the growth indicators and input-output ratio of different ginseng cultivation patterns,and conform that the soilless cultivation technology for organic ginseng is feasible. And this technology provides theoretical basis and technological feasibility for the sustainable development of ginseng industry.
文摘The sixth generation(6G)mobile network is envisaged to be commercially deployed around 2030,which will profoundly change people's lifestyles and accelerate the digitalization of society.To ensure that the requirements of 6G can be achieved,it is essential to establish a set of key performance indicators(KPIs).This paper comprehensively assesses the KPIs not only from the service requirements but also from the technical feasibility points of view.Specifically,theoretical derivations of KPIs have been clarified,and numerical evaluations have been conducted with reasonable technical assumptions.Evaluation results show that some KPIs defined from the service requirements can be improved through advanced technologies while some are still challenging for practical implementations,such as Tbps-level peak data rate and 0.1 ms user plane latency.In addition,it is also necessary to comply with multiple KPIs for some cases.Furthermore,based on the technical analysis,the potential enabling technologies are outlined and foreseeable implementation challenges as well as possible solutions are presented,which promotes a more reasonable design for 6G mobile network.
基金supported by the National High Technology Research and Development Program (Nos. 2012AA061501, 2012AA061502)the National Natural Science Foundation of China (No. 50934002)
文摘Bioleaching of chalcopyrite often encountered the formation of passivation layer,which inhibited the leaching process and resulted in a low leaching rate.This inhibitory effect can be eliminated by thermophilic bioleaching.The industrial test of BioCOP technology based on thermophiles was successfully completed,which confirmed the feasibility of chalcopyrite bioleaching.However,industrial leaching rate of chalcopyrite heap bioleaching is lower.This paper described the development status and industrial test of chalcopyrite heap bioleaching technology.The reasons for the lower efficiency of chalcopyrite heap bioleaching were analyzed.The strategies for successful chalcopyrite heap bioleaching were proposed.
