One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific object...One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific objectives,measurement targets,and measurement requirements for the proposed Gas and Ion Analyzer(GIA).The GIA is designed for in-situ mass spectrometry of neutral gases and low-energy ions,such as hydrogen,carbon,and oxygen,in the vicinity of 311P.Ion sampling techniques are essential for the GIA's Time-of-Flight(TOF)mass analysis capabilities.In this paper,we present an enhanced ion sampling technique through the development of an ion attraction model and an ion source model.The ion attraction model demonstrates that adjusting attraction grid voltage can enhance the detection efficiency of low-energy ions and mitigate the repulsive force of ions during sampling,which is influenced by the satellite's surface positive charging.The ion source model simulates the processes of gas ionization and ion multiplication.Simulation results indicate that the GIA can achieve a lower pressure limit below 10-13Pa and possess a dynamic range exceeding 10~9.These performances ensure the generation of ions with stable and consistent current,which is crucial for high-resolution and broad dynamic range mass spectrometer analysis.Preliminary testing experiments have verified GIA's capability to detect gas compositions such as H2O and N2.In-situ measurements near 311P using GIA are expected to significantly contribute to our understanding of asteroid activity mechanisms,the evolution of the atmospheric and ionized environments of main-belt comets,the interactions with solar wind,and the origin of Earth's water.展开更多
This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensi...This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.展开更多
To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristi...To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristics and the process of vortex and flutter generation of the segment models under different rain intensities and angles of attack are tested by considering several typical main girder sections as examples. The test results indicate that the start and end wind speeds,interval length and number of vortex vibrations remain unchanged when it is raining, rainfall will reduce the windinduced vortex response. When test rain intensity is large, the decrease of amplitude is obvious. However, after considering the rain intensity similarity in this study, all of actual maximum rain intensities after conversion approach the domestic extreme rain intensity of approximately 709 mm/h. It can be observed that rainfall has a limited influence on the dynamic characteristics of the structure and vortex vibration response. When the test rain intensity is 120 mm/h, the critical wind speed of the model flutter increases by 20%-30%. However, after considering the rain intensity similarity ratio, the influence of rainfall on the wind-induced flutter instability of the bridge girder may be ignored.展开更多
A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous...A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.展开更多
Drinking water supply for the Main Ethiopian Rift (MER) area principally relies on groundwater wells and springs and is characterized by fluoride contamination. New analyses reveal that the F^- geochemical anomaly is ...Drinking water supply for the Main Ethiopian Rift (MER) area principally relies on groundwater wells and springs and is characterized by fluoride contamination. New analyses reveal that the F^- geochemical anomaly is associated with other potentially toxic elements such as As,B,Mo,U,Al,Fe and Mn. Particularly,35%of the 23 investigated groundwater wells and 70%of the 14 hot springs(and展开更多
The Himalaya, a fold\|and\|thrust belt in the northern margin of the Indian continent, is characterized by thrust tectoncis (Schelling and Arita, 1991). It consists mainly of three thrust\|bounded lithotectonic units:...The Himalaya, a fold\|and\|thrust belt in the northern margin of the Indian continent, is characterized by thrust tectoncis (Schelling and Arita, 1991). It consists mainly of three thrust\|bounded lithotectonic units: from south to north the Sub\|Himalayan imbricate zone, the Lesser Himalayan thrust package (LH) and the Higher Himalayan thrust sheet (HH) with the overlying Tethys Himalayan sequence. These units are separated by a series of propagated thrusts, i.e. from south to north the Himalayan Frontal Fault (HFF), Main Boundary Thrust (MBT) and Main Central Thrust (MCT). These thrusts are splays off of an underlying mid\|crustal subhorizontal d$B;D(Jollement (Main Detachmen Trust or Main Himalayan Thrust), and were propagated southward with time. Among these thrusts the MCT is most important intracrustal thrust in considering the geological evolution of the Himalaya, and is controversial regarding its location and nature. In western and eastern Nepal the Higher Himalayan Crystalline sheet is thrust over the Lesser Himalayan rocks along the MCT. In the Kathmandu area of central Nepal also the high\|grade rocks of the HH with the overlying Tethyan sediments covers southward the Lesser Himalayan rocks, and form the Kathmandu nappe. In the north of the Kathmandu nappe the Higher Himalayan crystallines are skirted by the Main Central Thrust zone (MCT zone) which consists of green and black phyllites with sporadic garnet snow\|ball garnet and calcareous schist associated with characteristic mylonitic augen gneiss. The southern margin of the nappe is bounded by the Mahabharat Thrust (MT: Stoecklin, 1990) with a narrow zone of the LH which is cut by the MBT. But the relationship of the MCT in the north and the MT in the south is disputable and important (Arita et al., 1997: Rai et al., 1998: Upreti and Le Fort, 1999), and in the margin of the Kathmandu nappe the MCT zone has not been confirmed.展开更多
The Arun mega\|antiform, a large N—S structure transversal to the tectonic trend of the E Nepal Himalaya, is a tectonic window offering a complete section of the Himalayan nappe pile, from the Lesser Himalayan zone t...The Arun mega\|antiform, a large N—S structure transversal to the tectonic trend of the E Nepal Himalaya, is a tectonic window offering a complete section of the Himalayan nappe pile, from the Lesser Himalayan zone to the Tethyan Himalaya. At the northern end of the Arun tectonic window (ATW), the Ama Drime—Nyonno Ri range of south Tibet exposes a section of that portion of the Main Central Thrust (MCT) zone and Lesser Himalayan Crystallines (LHC) which elsewhere in Nepal is concealed below the overlying Higher Himalayan Crystalline (HHC) nappe (Fig. 1). As throughout the Himalaya at the structural level of the MCT, the ATW is characterized by an inverted metamorphic field gradient characterized by a progression from chlorite to sillimanite grade from low to high structural levels of the nappe pile. Metamorphic peak temperatures rise from circa 400℃ in the pelitic and psammitic Precambrian metasediments of the Lesser Himalayan Tumlingtar Unit, to 550～620℃ in the overlying LHC, to over 700℃ in the muscovite\|free Barun Gneiss, the lowermost HHC unit in the Arun valley.展开更多
It has become general for surface waters being polluted by micro organic compounds. In order to know the current pollution situation and the properties of micro organic compounds in the Changjiang River, a test was pe...It has become general for surface waters being polluted by micro organic compounds. In order to know the current pollution situation and the properties of micro organic compounds in the Changjiang River, a test was performed on micro organic compounds in the water, bottom material and fish bodies which were sampled from major city river reaches of the Changjiang River. Based on the test result, researchers described and analyzed the sorts, concentration level and distribution features of micro organic compounds. A comprehensive evaluation was conducted by adopting the method of MEG (Multimedia Environmental Goals). The study indicated that ① the water body of major city river reaches of the Changjiang River has been generally polluted. In the test, totally 12 types with 308 kinds of organic compounds were detected. The main pollutants were paraffins, PAHs and lipids; and ② micro organic pollutant content in fish bodies was generally higher than that in bottom material which is in turn higher than that in water; and ③ pollution is relatively severe in the river reaches of mid-to-large comprehensive industrial cities with fairly great TAS (Total Ambient Severity) of public health and ecological system.展开更多
This paper is the analysis of the main body, the object and their relationship concerning research of traditional Chinese medicine. The result proved that the main body of research of traditional Chinese medicine is r...This paper is the analysis of the main body, the object and their relationship concerning research of traditional Chinese medicine. The result proved that the main body of research of traditional Chinese medicine is researchers who possessed the fundamentals of traditional Chinese medicine. It is the objects of research of traditional Chinese medicine that origin of a class of traditional Chinese medical literature consisting of herbals which focus on descriptions of individual drugs; the relationship of the technological process of preparing Chinese medicine, as by parching, roasting, baking, steaming, soaking, and simmering, etc.;and technology of separating, extracting and purifying for composition; traditional Chinese medicine dynamics of one of the 12 two-hour periods into which the day was formerly divided before the introduction of western chronology; compatibility of medicines in active compositions; patent, effectiveness for a given period of time and constantly changing of traditional Chinese medicine.The relationship between the main body and the objects was that the former depends on the latter ones and the main body has subjective initiative as fully as possible.展开更多
The laws of water consumption in corn,peanuts and millet on the semi-drought area of western Liaoning Province were studied through the FAO-Penman Monteith method and the water balance method.Among three corps,the amo...The laws of water consumption in corn,peanuts and millet on the semi-drought area of western Liaoning Province were studied through the FAO-Penman Monteith method and the water balance method.Among three corps,the amount of the day water demand,the whole growth period water demand and the soil water deficit of corn were all the largest.At the same time,its degree of agreement between the water demand and the level of precipitation was the worst,and its average in crop coefficient was larger.The amount of th...展开更多
Objective To summarize the clinical characteristics and the effect of pulmonary endarterectomy(PEA)in CTEPH patients with unilateral main pulmonary artery occlusion.Methods Of 160 CTEPH patients operated between Janua...Objective To summarize the clinical characteristics and the effect of pulmonary endarterectomy(PEA)in CTEPH patients with unilateral main pulmonary artery occlusion.Methods Of 160 CTEPH patients operated between January2004 and March 2018 at our center,13(8.1%)had complete main pulmonary artery occlusion.Patients were included if the ventilation/perfusion(V/Q)scan revealed nonperfusion of an entire lung and the pathological examination showed chronic thromboembolic.展开更多
As an old industrial base, Northeast China is one of the most important grain production base. To rejuvenate Northeast China, it is necessary to strengthen farming products processing, lengthen industrial chain and de...As an old industrial base, Northeast China is one of the most important grain production base. To rejuvenate Northeast China, it is necessary to strengthen farming products processing, lengthen industrial chain and develop sustainable agriculture.展开更多
China's food security mainly depends on the core areas of food production.Under the dual constraints of resource scarcity and environmental degradation,improving the grain production efficiency of the main grain-p...China's food security mainly depends on the core areas of food production.Under the dual constraints of resource scarcity and environmental degradation,improving the grain production efficiency of the main grain-producing areas has become the fundamental way to strengthen the grain production capacity and improve the national food security capability,and to improve the efficiency of grain production in major grain-producing areas requires empirical support.This paper used the Super SBM model and the Malmquist index to measure the grain production efficiency of the main grain-producing areas from 2001 to 2020 from both static and dynamic perspectives,and compared the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas.The results showed that from 2001 to 2020,the grain production in the main grain-producing areas was in a relatively ineffective state,and the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas were obvious.The order of grain production efficiency in different soil types was black soil region>red-yellow soil region>paddy soil region>fluvo-aquic soil region,and the order of grain production efficiency of the provinces(autonomous regions)in the main grain-producing areas was Jilin>Heilongjiang>Inner Mongolia>Jiangxi>Hunan>Sichuan>Hubei>Jiangsu>Liaoning>Henan>Anhui>Shandong>Hebei.From 2001 to 2020,the total factor productivity of grain in the main grain-producing areas increased,but due to the trade-off between the technological progress and the growth of technical efficiency,the increase in the total factor productivity of grain in the main grain-producing areas was small,and the growth mainly came from the increase of input factors in this period.The total factor productivity of grain in Hebei,Heilongjiang,Liaoning,Jilin,Inner Mongolia,Shandong,Jiangsu,Henan and Anhui increased,but the increase was small,while the total factor productivity of grain in Jiangxi,Sichuan,Hunan and Hubei provinces declined.展开更多
Effects of transgenic Cry1Ac plus CpTI cotton(double genes cotton) on development of main parasitoids were studied in the laboratory.Compared with the traditional cotton,the differences of
The fundamental protection principles of the new armours for main battle tanks against kinetic energy projectiles (KE) and chemical energy weapons (CE)--shaped charges are shortly described and their efficiency agains...The fundamental protection principles of the new armours for main battle tanks against kinetic energy projectiles (KE) and chemical energy weapons (CE)--shaped charges are shortly described and their efficiency against both threats discussed. The armour topics can be split into: "perpendicular or zero-degree armours", such as rolled homogeneous armour (RHA), also with extremely high strength, ceramics, glass, liquid filled columns and explosive filled cells,"inclined armours", as spaced RHA plates with their corner effects, bulging armour, additive and integrated explosive reactive armours (ERA) and "hard kill active defence possibilities" in different defeating distances.展开更多
基金Supported by the National Natural Science Foundation of China(42474239,41204128)China National Space Administration(Pre-research project on Civil Aerospace Technologies No.D010301)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA17010303)。
文摘One of the detection objectives of the Chinese Asteroid Exploration mission is to investigate the space environment near the Main-belt Comet(MBC,Active Asteroid)311P/PANSTARRS.This paper outlines the scientific objectives,measurement targets,and measurement requirements for the proposed Gas and Ion Analyzer(GIA).The GIA is designed for in-situ mass spectrometry of neutral gases and low-energy ions,such as hydrogen,carbon,and oxygen,in the vicinity of 311P.Ion sampling techniques are essential for the GIA's Time-of-Flight(TOF)mass analysis capabilities.In this paper,we present an enhanced ion sampling technique through the development of an ion attraction model and an ion source model.The ion attraction model demonstrates that adjusting attraction grid voltage can enhance the detection efficiency of low-energy ions and mitigate the repulsive force of ions during sampling,which is influenced by the satellite's surface positive charging.The ion source model simulates the processes of gas ionization and ion multiplication.Simulation results indicate that the GIA can achieve a lower pressure limit below 10-13Pa and possess a dynamic range exceeding 10~9.These performances ensure the generation of ions with stable and consistent current,which is crucial for high-resolution and broad dynamic range mass spectrometer analysis.Preliminary testing experiments have verified GIA's capability to detect gas compositions such as H2O and N2.In-situ measurements near 311P using GIA are expected to significantly contribute to our understanding of asteroid activity mechanisms,the evolution of the atmospheric and ionized environments of main-belt comets,the interactions with solar wind,and the origin of Earth's water.
基金Project(WPUKFJJ2019-19)supported by the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,ChinaProject(51974317)supported by the National Natural Science Foundation of China。
文摘This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.
基金Projects(20B062,19B054)supported by Excellent Youth Program of Hunan Education Department,ChinaProject(2019JJ50688)supported by Hunan Provincial Natural Science Foundation of ChinaProject(kq195004)supported by Changsha Science and Technology Bureau Project,China。
文摘To study the additional aerodynamic effect on a bridge girder under the action of wind-driven rain, the rainfall similarity considering raindrop impact and surface water is first given. Then, the dynamic characteristics and the process of vortex and flutter generation of the segment models under different rain intensities and angles of attack are tested by considering several typical main girder sections as examples. The test results indicate that the start and end wind speeds,interval length and number of vortex vibrations remain unchanged when it is raining, rainfall will reduce the windinduced vortex response. When test rain intensity is large, the decrease of amplitude is obvious. However, after considering the rain intensity similarity in this study, all of actual maximum rain intensities after conversion approach the domestic extreme rain intensity of approximately 709 mm/h. It can be observed that rainfall has a limited influence on the dynamic characteristics of the structure and vortex vibration response. When the test rain intensity is 120 mm/h, the critical wind speed of the model flutter increases by 20%-30%. However, after considering the rain intensity similarity ratio, the influence of rainfall on the wind-induced flutter instability of the bridge girder may be ignored.
基金Project(JC200903180555A) supported by Shenzhen City Science and Technology Plan, China
文摘A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.
文摘Drinking water supply for the Main Ethiopian Rift (MER) area principally relies on groundwater wells and springs and is characterized by fluoride contamination. New analyses reveal that the F^- geochemical anomaly is associated with other potentially toxic elements such as As,B,Mo,U,Al,Fe and Mn. Particularly,35%of the 23 investigated groundwater wells and 70%of the 14 hot springs(and
文摘The Himalaya, a fold\|and\|thrust belt in the northern margin of the Indian continent, is characterized by thrust tectoncis (Schelling and Arita, 1991). It consists mainly of three thrust\|bounded lithotectonic units: from south to north the Sub\|Himalayan imbricate zone, the Lesser Himalayan thrust package (LH) and the Higher Himalayan thrust sheet (HH) with the overlying Tethys Himalayan sequence. These units are separated by a series of propagated thrusts, i.e. from south to north the Himalayan Frontal Fault (HFF), Main Boundary Thrust (MBT) and Main Central Thrust (MCT). These thrusts are splays off of an underlying mid\|crustal subhorizontal d$B;D(Jollement (Main Detachmen Trust or Main Himalayan Thrust), and were propagated southward with time. Among these thrusts the MCT is most important intracrustal thrust in considering the geological evolution of the Himalaya, and is controversial regarding its location and nature. In western and eastern Nepal the Higher Himalayan Crystalline sheet is thrust over the Lesser Himalayan rocks along the MCT. In the Kathmandu area of central Nepal also the high\|grade rocks of the HH with the overlying Tethyan sediments covers southward the Lesser Himalayan rocks, and form the Kathmandu nappe. In the north of the Kathmandu nappe the Higher Himalayan crystallines are skirted by the Main Central Thrust zone (MCT zone) which consists of green and black phyllites with sporadic garnet snow\|ball garnet and calcareous schist associated with characteristic mylonitic augen gneiss. The southern margin of the nappe is bounded by the Mahabharat Thrust (MT: Stoecklin, 1990) with a narrow zone of the LH which is cut by the MBT. But the relationship of the MCT in the north and the MT in the south is disputable and important (Arita et al., 1997: Rai et al., 1998: Upreti and Le Fort, 1999), and in the margin of the Kathmandu nappe the MCT zone has not been confirmed.
文摘The Arun mega\|antiform, a large N—S structure transversal to the tectonic trend of the E Nepal Himalaya, is a tectonic window offering a complete section of the Himalayan nappe pile, from the Lesser Himalayan zone to the Tethyan Himalaya. At the northern end of the Arun tectonic window (ATW), the Ama Drime—Nyonno Ri range of south Tibet exposes a section of that portion of the Main Central Thrust (MCT) zone and Lesser Himalayan Crystallines (LHC) which elsewhere in Nepal is concealed below the overlying Higher Himalayan Crystalline (HHC) nappe (Fig. 1). As throughout the Himalaya at the structural level of the MCT, the ATW is characterized by an inverted metamorphic field gradient characterized by a progression from chlorite to sillimanite grade from low to high structural levels of the nappe pile. Metamorphic peak temperatures rise from circa 400℃ in the pelitic and psammitic Precambrian metasediments of the Lesser Himalayan Tumlingtar Unit, to 550～620℃ in the overlying LHC, to over 700℃ in the muscovite\|free Barun Gneiss, the lowermost HHC unit in the Arun valley.
文摘It has become general for surface waters being polluted by micro organic compounds. In order to know the current pollution situation and the properties of micro organic compounds in the Changjiang River, a test was performed on micro organic compounds in the water, bottom material and fish bodies which were sampled from major city river reaches of the Changjiang River. Based on the test result, researchers described and analyzed the sorts, concentration level and distribution features of micro organic compounds. A comprehensive evaluation was conducted by adopting the method of MEG (Multimedia Environmental Goals). The study indicated that ① the water body of major city river reaches of the Changjiang River has been generally polluted. In the test, totally 12 types with 308 kinds of organic compounds were detected. The main pollutants were paraffins, PAHs and lipids; and ② micro organic pollutant content in fish bodies was generally higher than that in bottom material which is in turn higher than that in water; and ③ pollution is relatively severe in the river reaches of mid-to-large comprehensive industrial cities with fairly great TAS (Total Ambient Severity) of public health and ecological system.
文摘This paper is the analysis of the main body, the object and their relationship concerning research of traditional Chinese medicine. The result proved that the main body of research of traditional Chinese medicine is researchers who possessed the fundamentals of traditional Chinese medicine. It is the objects of research of traditional Chinese medicine that origin of a class of traditional Chinese medical literature consisting of herbals which focus on descriptions of individual drugs; the relationship of the technological process of preparing Chinese medicine, as by parching, roasting, baking, steaming, soaking, and simmering, etc.;and technology of separating, extracting and purifying for composition; traditional Chinese medicine dynamics of one of the 12 two-hour periods into which the day was formerly divided before the introduction of western chronology; compatibility of medicines in active compositions; patent, effectiveness for a given period of time and constantly changing of traditional Chinese medicine.The relationship between the main body and the objects was that the former depends on the latter ones and the main body has subjective initiative as fully as possible.
基金Supported by the National Key Scientific and Technological Project,China (2006BAD29b06)
文摘The laws of water consumption in corn,peanuts and millet on the semi-drought area of western Liaoning Province were studied through the FAO-Penman Monteith method and the water balance method.Among three corps,the amount of the day water demand,the whole growth period water demand and the soil water deficit of corn were all the largest.At the same time,its degree of agreement between the water demand and the level of precipitation was the worst,and its average in crop coefficient was larger.The amount of th...
文摘Objective To summarize the clinical characteristics and the effect of pulmonary endarterectomy(PEA)in CTEPH patients with unilateral main pulmonary artery occlusion.Methods Of 160 CTEPH patients operated between January2004 and March 2018 at our center,13(8.1%)had complete main pulmonary artery occlusion.Patients were included if the ventilation/perfusion(V/Q)scan revealed nonperfusion of an entire lung and the pathological examination showed chronic thromboembolic.
文摘As an old industrial base, Northeast China is one of the most important grain production base. To rejuvenate Northeast China, it is necessary to strengthen farming products processing, lengthen industrial chain and develop sustainable agriculture.
基金Supported by Science of China University Journals(CUJS2021-027)China Agricultural Journals Website 2021(CAJW2021-033)。
文摘China's food security mainly depends on the core areas of food production.Under the dual constraints of resource scarcity and environmental degradation,improving the grain production efficiency of the main grain-producing areas has become the fundamental way to strengthen the grain production capacity and improve the national food security capability,and to improve the efficiency of grain production in major grain-producing areas requires empirical support.This paper used the Super SBM model and the Malmquist index to measure the grain production efficiency of the main grain-producing areas from 2001 to 2020 from both static and dynamic perspectives,and compared the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas.The results showed that from 2001 to 2020,the grain production in the main grain-producing areas was in a relatively ineffective state,and the differences in grain production efficiency among different soil types and different provinces(autonomous regions)in the main grain-producing areas were obvious.The order of grain production efficiency in different soil types was black soil region>red-yellow soil region>paddy soil region>fluvo-aquic soil region,and the order of grain production efficiency of the provinces(autonomous regions)in the main grain-producing areas was Jilin>Heilongjiang>Inner Mongolia>Jiangxi>Hunan>Sichuan>Hubei>Jiangsu>Liaoning>Henan>Anhui>Shandong>Hebei.From 2001 to 2020,the total factor productivity of grain in the main grain-producing areas increased,but due to the trade-off between the technological progress and the growth of technical efficiency,the increase in the total factor productivity of grain in the main grain-producing areas was small,and the growth mainly came from the increase of input factors in this period.The total factor productivity of grain in Hebei,Heilongjiang,Liaoning,Jilin,Inner Mongolia,Shandong,Jiangsu,Henan and Anhui increased,but the increase was small,while the total factor productivity of grain in Jiangxi,Sichuan,Hunan and Hubei provinces declined.
文摘Effects of transgenic Cry1Ac plus CpTI cotton(double genes cotton) on development of main parasitoids were studied in the laboratory.Compared with the traditional cotton,the differences of
文摘The fundamental protection principles of the new armours for main battle tanks against kinetic energy projectiles (KE) and chemical energy weapons (CE)--shaped charges are shortly described and their efficiency against both threats discussed. The armour topics can be split into: "perpendicular or zero-degree armours", such as rolled homogeneous armour (RHA), also with extremely high strength, ceramics, glass, liquid filled columns and explosive filled cells,"inclined armours", as spaced RHA plates with their corner effects, bulging armour, additive and integrated explosive reactive armours (ERA) and "hard kill active defence possibilities" in different defeating distances.
