On February 6,2023,two earthquakes with magnitudes of M_(W) 7.8 and M_(W) 7.5 struck southeastern Turkey,causing significant casualties and economic losses.These seismic events occurred along the East Anatolian Fault ...On February 6,2023,two earthquakes with magnitudes of M_(W) 7.8 and M_(W) 7.5 struck southeastern Turkey,causing significant casualties and economic losses.These seismic events occurred along the East Anatolian Fault Zone,a convergent boundary between the Arabian Plate and the Anatolian Subplate.In this study,we analyze the M_(W) 7.8 and M_(W) 7.5 earthquakes by comparing their aftershock relocations,tomographic images,and stress field inversions.The earthquakes were localized in the upper crust and exhibited steep dip angles.Furthermore,the aftershocks occurred either close to the boundaries of low and high P-wave velocity anomaly zones or within the low P-wave velocity anomaly zones.The East Anatolia Fault,associated with the M_(W) 7.8 earthquake,and the SürgüFault,related to the M_(W) 7.5 earthquake,predominantly experienced shear stress.However,their western sections experienced a combination of strike-slip and tensile stresses in addition to shear stress.The ruptures of the M_(W) 7.8 and M_(W) 7.5 earthquakes appear to have bridged a seismic gap that had seen sparse seismicity over the past 200 years prior to the 2023 Turkey earthquake sequence.展开更多
On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, ...On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, we provide an overview of this earthquake, focusing on the slip distribution of the mainshock and its relationship with the preceding swarm. We also reexamined the source areas of other large earthquakes that occurred around the Sea of Japan in the past and compared them with the Matsushiro earthquake swarm in central Japan from1964 to 1968. The difference between the Matsushiro earthquake swarm and the Noto earthquake swarm is the surrounding stress field. The Matsushiro earthquake swarm was a strike-slip stress field, so the cracks in the crust were oriented vertically. This allowed fluids seeped from the depths to rise and flow out to the surface. On the other hand, the Noto area was a reverse fault stress field. Therefore, the cracks in the earth's crust were oriented horizontally. Fluids flowing underground in deep areas could not rise and spread over a wide area in the horizontal plane. This may have caused a large amount of fluid to accumulate underground, triggering a large earthquake. Although our proposed mechanism does not take into account other complex geological conditions into consideration, it may provide a simple way to explain why the Noto swarm is followed by a large earthquake while other swarms are not.展开更多
High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Fur...High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.展开更多
We investigated the relationships between the existence of exercise partners and exercise habits among Japanese university students. Subjects were 650 university students (539 males, 111 females;age range 18 - 27 year...We investigated the relationships between the existence of exercise partners and exercise habits among Japanese university students. Subjects were 650 university students (539 males, 111 females;age range 18 - 27 years). They responded to an anonymous questionnaire asking about current and past exercise habits, preference for exercise (i.e., like or dislike of exercise), and the existence of one or more exercise partners. In the results, the existence of exercise partners had a significant association with exercise habits at each school stage in both genders. Exercise preference had a significant association with exercise habits during high school in both genders;during primary and middle school, however, this association was significant only in males. In males, exercise habits and the preference for exercising in high school affected current exercise habits. In females, only exercise habits in high school affected current exercise habits. Our results suggest that the existence of one or more exercise partners is important for the practice of exercise, as well as the preference for exercise. They also suggest that continuity of exercise habits is different between males and females.展开更多
Magnesium alloy is attractive for lightweight construction but often suffers from poor corrosion resistance and low strength.Cavitation processing with chemicals,i.e.,multifunction cavitation(MFC),was introduced to fo...Magnesium alloy is attractive for lightweight construction but often suffers from poor corrosion resistance and low strength.Cavitation processing with chemicals,i.e.,multifunction cavitation(MFC),was introduced to form a high-corrosion film and improve the fatigue properties of an AZ31 magnesium alloy.Surface analysis and plane bending fatigue tests were conducted for the MFC-treated magnesium alloy at a stress ratio,R,of-1.The mechanical action of cavitation bubbles improved the fatigue life of magnesium alloys due to increasing the surface hardness and generating compressive residual stress.However,the combined mechanical and electrochemical action during MFC formed pits on the surface.These pits were large enough to easily nucleate an initial fatigue crack.In addition,the magnesium alloys without pit formation,for which a coating process using phosphoric acid was conducted after MFC using water,showed superior fatigue properties.展开更多
Over the last two decades,extensive study has been done on two-dimensional Molybdenum Sulphide(MoS_(2))due to its outstanding features in energy storage applications.Although MoS_(2)has a lot of active sulphur edges,t...Over the last two decades,extensive study has been done on two-dimensional Molybdenum Sulphide(MoS_(2))due to its outstanding features in energy storage applications.Although MoS_(2)has a lot of active sulphur edges,the presence of inactive surfaces leads to limit conductivity and efficiency.Hence,in this article,we aimed to promote the additional active sites by doping various weight percentages(2%,4%,6%,8%and 10%)of Nickel(Ni)into the MoS_(2)matrix by simple hydrothermal technique,and their doping effects were investigated with the help of Physio-chemical analyses.X-ray diffraction(XRD)pattern,Raman,and chemical composition(XPS)analyses were used to confirm the Ni incorporation in MoS_(2)nanosheets.Microscopic investigations demonstrated that Ni-doped MoS_(2)nanosheets were vertically aligned with enhanced interlayer spacing.Cyclic voltammetry,Galvanostatic charge-discharge,and electrochemical impedance spectroscopy investigations were used to characterize the electrochemical characteristics.The 6%Ni-doped MoS_(2)electrode material showed better CSPof 528.7 F/g@1 A/g and excellent electrochemical stability(85%of capacitance retention after 10,000 cycles at 5 A/g)compared to other electrode materials.Furthermore,the solid-state asymmetric supercapacitor was assembled using Nidoped MoS_(2)and graphite as anode and cathode materials and analysed the electrochemical properties in the two-electrode system.To determine the impact of the Ni-atom on the MoS_(2)surface,firstprinciples computations were performed.Further,it was examined for electronic band structure,the projected density of states(PDOS)and Bader charge transfer analyses.展开更多
采用BIOME-BGC模型对广东鹤山的马占相思（Acacia mangium）人工林生态系统1985-2100年间的碳格局及其动态变化进行了模拟。结果表明，马占相思生物量在前12a增长较快，之后增长缓慢，最终达到300t hm^-2；预计2100年马占相思生物量在...采用BIOME-BGC模型对广东鹤山的马占相思（Acacia mangium）人工林生态系统1985-2100年间的碳格局及其动态变化进行了模拟。结果表明，马占相思生物量在前12a增长较快，之后增长缓慢，最终达到300t hm^-2；预计2100年马占相思生物量在于、根、叶中的分配分别为73.91％、21.74％和4.35％。马占相思人工林的碳贮量在前12a增长较快，之后增长缓慢并最终维持在325t C hm^-2左右，在造林初始阶段主要分布于土壤中，之后在植被、土壤和凋落物3大碳库中的分配分别为43.08％、52.30％和4.62％；马占相思净初级生产力（NPP）在4-12a较大，最大可达11t C hm^-2，之后下降至3-6t C hm^-2；马占相思叶面积指数（LAX）前3a增长迅速，5a达到7.84，之后下降，约为2.7-5.0；LAJ与NPP的回归分析结果显示LAI可能是限制马占相思林NPP增长的主要因子。模拟结果还显示马占相思林前期生长迅速，但随后生长缓慢，叶生物量还出现负增长现象。因此，我国南亚热带地区在以马占相思作为先锋树种进行地带性森林植被恢复时，可在12a后进行林分改造。展开更多
Arid and semi-arid areas are the most vulnerable regions to climate change. Clear understanding of the effects of climate change on ecosystems in arid and semi-arid regions and the ecosystem vulnerability is important...Arid and semi-arid areas are the most vulnerable regions to climate change. Clear understanding of the effects of climate change on ecosystems in arid and semi-arid regions and the ecosystem vulnerability is important for ecosystem management under the background of climate change. In this study, we conducted a vulnerability assessment on various ecosystems from 1982 to 2013 in western China with large areas of arid and semi-arid lands based on the Time-Integrated Normalized Difference Vegetation Index （TINDVI） data and climate data. The results indicated that grasslands were the most vulnerable ecosystem to climate change in western China, especially for those in Tibetan Plateau. Croplands in oases were not vulnerable to climate change compared to rain-fed croplands in semi-arid regions （e.g. Gansu and Inner Mongolia）, which was attributed to the well-developed drip irrigation technology in oases. Desert and Gobi ecosystems were slightly vulnerable to climate change during the past several decades. The assessment results, as revealed in this study, can provide a reference for taking appropriate actions to protect the ecosystems in western China.展开更多
This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province(southern China). The chemical ...This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province(southern China). The chemical weathering characteristics of the studied profile were investigated and the inheritance relationships between the terra rossa and overlying strata were discussed. The results show that there is no remarkable variation in the major elements and weathering indices from the rock–soil interface to the topsoil, indicating that the studied profile was not typical for in situ crustal chemical weathering. The terra rossa were mainly composed of Si O_2, Al_2O_3 and Fe_2O_3. Compared with the insoluble residues and overlying strata, the terra rossa are characterized by an enrichment of Y and Cs and depletion of Ba and Sr. The subsoil shows a notable Ce negative anomaly, characterized by heavy rare earth element enrichment(L/H = 1.55–3.74), whereas the topsoil shows a positive Ce anomaly with light rare earth element enrichment(L/H = 5.93–9.14). According to Laterite-forming capacity estimates, the terra rossa could not have only been formed from acid-insoluble residues from the bedrock; Al_2O_3 versus Fe_2O_3and Nb plotted against Ta show significant positive correlations between the terra rossa and overlying strata. The Eu/Eu* versusGd_N/Yb_Nand ternary diagrams for Sc, Th, Zr, and Ta suggest that the overlying strata could also provide parent materials for the genesis of terra rossa.展开更多
This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, a...This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.展开更多
In this paper,10-day spatio-temporal response of vegetation to the change of temperature and precipitation in spring,summer,autumn and whole year during the period of 1998―2009 was analyzed based on the data of SPOT ...In this paper,10-day spatio-temporal response of vegetation to the change of temperature and precipitation in spring,summer,autumn and whole year during the period of 1998―2009 was analyzed based on the data of SPOT VEGETATION-NDVI and 10-day average temperature or precipitation from 54 meteorological stations in Xinjiang.The results show that the response of 10-day NDVI to temperature was more significant than that to precipitation,and the maximal response of vegetation to temperature and precipitation lagged for two 10-day periods.Seasonally,the effect of temperature and precipitation on vegetation NDVI was most marked in autumn,then in spring,and it was not significant in summer.The response of vegetation to 10-day change of meteorological factors was positive with a long affecting duration in spring,and it had a relatively short affecting duration in autumn and summer.Spatially,the 10-day maximal response of NDVI to temperature in northern Xinjiang was higher than that in southern Xinjiang.The correlation between the 10-day NDVI in whole year and the temperature in the 0-8th 10-day period was significantly higher than that between the annual NDVI and the annual temperature at all meteorological stations;the interannual change of NDVI was accordant well with the change of annual precipitation.However,the effect of precipitation within a year on NDVI was not strong.The results indicated that interannual change of temperature was not the dominant factor affecting the change of vegetation NDVI in Xinjiang,but the decrease of annual precipitation was the main factor resulting in the fluctuation of vegetation coverage.Ten-day average temperature was an important factor to promote vegetation growth in Xinjiang within a year,but the effect of precipitation on vegetation growth within a year was not strong.展开更多
Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris...Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central Japan.On 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid area.The first type was associated with the progress of surface flow from the upper stream on unsaturated channel deposits.The second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this saturation.The third type was associated with changes in the downstream topography caused by erosion.The flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation point.Surges with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger duration.Our observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.42130312 and 4198810101)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK07)
文摘On February 6,2023,two earthquakes with magnitudes of M_(W) 7.8 and M_(W) 7.5 struck southeastern Turkey,causing significant casualties and economic losses.These seismic events occurred along the East Anatolian Fault Zone,a convergent boundary between the Arabian Plate and the Anatolian Subplate.In this study,we analyze the M_(W) 7.8 and M_(W) 7.5 earthquakes by comparing their aftershock relocations,tomographic images,and stress field inversions.The earthquakes were localized in the upper crust and exhibited steep dip angles.Furthermore,the aftershocks occurred either close to the boundaries of low and high P-wave velocity anomaly zones or within the low P-wave velocity anomaly zones.The East Anatolia Fault,associated with the M_(W) 7.8 earthquake,and the SürgüFault,related to the M_(W) 7.5 earthquake,predominantly experienced shear stress.However,their western sections experienced a combination of strike-slip and tensile stresses in addition to shear stress.The ruptures of the M_(W) 7.8 and M_(W) 7.5 earthquakes appear to have bridged a seismic gap that had seen sparse seismicity over the past 200 years prior to the 2023 Turkey earthquake sequence.
基金supported by the National Nature Science Foundation of China (No. 42130312)。
文摘On January 1, 2024 at 16:10:09 JST, an M_(j) 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, we provide an overview of this earthquake, focusing on the slip distribution of the mainshock and its relationship with the preceding swarm. We also reexamined the source areas of other large earthquakes that occurred around the Sea of Japan in the past and compared them with the Matsushiro earthquake swarm in central Japan from1964 to 1968. The difference between the Matsushiro earthquake swarm and the Noto earthquake swarm is the surrounding stress field. The Matsushiro earthquake swarm was a strike-slip stress field, so the cracks in the crust were oriented vertically. This allowed fluids seeped from the depths to rise and flow out to the surface. On the other hand, the Noto area was a reverse fault stress field. Therefore, the cracks in the earth's crust were oriented horizontally. Fluids flowing underground in deep areas could not rise and spread over a wide area in the horizontal plane. This may have caused a large amount of fluid to accumulate underground, triggering a large earthquake. Although our proposed mechanism does not take into account other complex geological conditions into consideration, it may provide a simple way to explain why the Noto swarm is followed by a large earthquake while other swarms are not.
基金This work was supported by the National Research Foundation of Korea(NRF)Grant funded by the Korean government(MSIT)(NRF-2018R1A5A1025224 and NRF-2021R1A4A1052051)This work was also supported by the National Research Foundation of Korea Grant funded by the Korean Government Ministry of Education and Science Technology(NRF-2021R1I1A3060193).
文摘High electrochemical stability and safety make Na+superionic conductor(NASICON)-class cathodes highly desirable for Na-ion batteries(SIBs).However,their practical capacity is limited,leading to low specific energy.Furthermore,the low electrical conductivity combined with a decline in capacity upon prolonged cycling(>1000 cycles)related to the loss of active material-carbon conducting contact regions contributes to moderate rate performance and cycling stability.The need for high specific energy cathodes that meet practical electrochemical requirements has prompted a search for new materials.Herein,we introduce a new carbon-coated Na_(3)VFe_(0.5)Ti_(0.5)(PO_(4))_(3)(NVFTP/C)material as a promising candidate in the NASICON family of cathodes for SIBs.With a high specific energy of∼457 Wh kg^(-1) and a high Na+insertion voltage of 3.0 V versus Na^(+)/Na,this cathode can undergo a reversible single-phase solid-solution and two-phase(de)sodiation evolution at 28 C(1 C=174.7 mAh g^(-1))for up to 10,000 cycles.This study highlights the potential of utilizing low-cost and highly efficient cathodes made from Earth-abundant and harmless materials(Fe and Ti)with enriched Na^(+)-storage properties in practical SIBs.
文摘We investigated the relationships between the existence of exercise partners and exercise habits among Japanese university students. Subjects were 650 university students (539 males, 111 females;age range 18 - 27 years). They responded to an anonymous questionnaire asking about current and past exercise habits, preference for exercise (i.e., like or dislike of exercise), and the existence of one or more exercise partners. In the results, the existence of exercise partners had a significant association with exercise habits at each school stage in both genders. Exercise preference had a significant association with exercise habits during high school in both genders;during primary and middle school, however, this association was significant only in males. In males, exercise habits and the preference for exercising in high school affected current exercise habits. In females, only exercise habits in high school affected current exercise habits. Our results suggest that the existence of one or more exercise partners is important for the practice of exercise, as well as the preference for exercise. They also suggest that continuity of exercise habits is different between males and females.
文摘Magnesium alloy is attractive for lightweight construction but often suffers from poor corrosion resistance and low strength.Cavitation processing with chemicals,i.e.,multifunction cavitation(MFC),was introduced to form a high-corrosion film and improve the fatigue properties of an AZ31 magnesium alloy.Surface analysis and plane bending fatigue tests were conducted for the MFC-treated magnesium alloy at a stress ratio,R,of-1.The mechanical action of cavitation bubbles improved the fatigue life of magnesium alloys due to increasing the surface hardness and generating compressive residual stress.However,the combined mechanical and electrochemical action during MFC formed pits on the surface.These pits were large enough to easily nucleate an initial fatigue crack.In addition,the magnesium alloys without pit formation,for which a coating process using phosphoric acid was conducted after MFC using water,showed superior fatigue properties.
文摘Over the last two decades,extensive study has been done on two-dimensional Molybdenum Sulphide(MoS_(2))due to its outstanding features in energy storage applications.Although MoS_(2)has a lot of active sulphur edges,the presence of inactive surfaces leads to limit conductivity and efficiency.Hence,in this article,we aimed to promote the additional active sites by doping various weight percentages(2%,4%,6%,8%and 10%)of Nickel(Ni)into the MoS_(2)matrix by simple hydrothermal technique,and their doping effects were investigated with the help of Physio-chemical analyses.X-ray diffraction(XRD)pattern,Raman,and chemical composition(XPS)analyses were used to confirm the Ni incorporation in MoS_(2)nanosheets.Microscopic investigations demonstrated that Ni-doped MoS_(2)nanosheets were vertically aligned with enhanced interlayer spacing.Cyclic voltammetry,Galvanostatic charge-discharge,and electrochemical impedance spectroscopy investigations were used to characterize the electrochemical characteristics.The 6%Ni-doped MoS_(2)electrode material showed better CSPof 528.7 F/g@1 A/g and excellent electrochemical stability(85%of capacitance retention after 10,000 cycles at 5 A/g)compared to other electrode materials.Furthermore,the solid-state asymmetric supercapacitor was assembled using Nidoped MoS_(2)and graphite as anode and cathode materials and analysed the electrochemical properties in the two-electrode system.To determine the impact of the Ni-atom on the MoS_(2)surface,firstprinciples computations were performed.Further,it was examined for electronic band structure,the projected density of states(PDOS)and Bader charge transfer analyses.
文摘采用BIOME-BGC模型对广东鹤山的马占相思（Acacia mangium）人工林生态系统1985-2100年间的碳格局及其动态变化进行了模拟。结果表明，马占相思生物量在前12a增长较快，之后增长缓慢，最终达到300t hm^-2；预计2100年马占相思生物量在于、根、叶中的分配分别为73.91％、21.74％和4.35％。马占相思人工林的碳贮量在前12a增长较快，之后增长缓慢并最终维持在325t C hm^-2左右，在造林初始阶段主要分布于土壤中，之后在植被、土壤和凋落物3大碳库中的分配分别为43.08％、52.30％和4.62％；马占相思净初级生产力（NPP）在4-12a较大，最大可达11t C hm^-2，之后下降至3-6t C hm^-2；马占相思叶面积指数（LAX）前3a增长迅速，5a达到7.84，之后下降，约为2.7-5.0；LAJ与NPP的回归分析结果显示LAI可能是限制马占相思林NPP增长的主要因子。模拟结果还显示马占相思林前期生长迅速，但随后生长缓慢，叶生物量还出现负增长现象。因此，我国南亚热带地区在以马占相思作为先锋树种进行地带性森林植被恢复时，可在12a后进行林分改造。
基金supported by the National Basic Research Program of China(2012CB956204)the National Natural Science Foundation of China(41101249)
文摘Arid and semi-arid areas are the most vulnerable regions to climate change. Clear understanding of the effects of climate change on ecosystems in arid and semi-arid regions and the ecosystem vulnerability is important for ecosystem management under the background of climate change. In this study, we conducted a vulnerability assessment on various ecosystems from 1982 to 2013 in western China with large areas of arid and semi-arid lands based on the Time-Integrated Normalized Difference Vegetation Index （TINDVI） data and climate data. The results indicated that grasslands were the most vulnerable ecosystem to climate change in western China, especially for those in Tibetan Plateau. Croplands in oases were not vulnerable to climate change compared to rain-fed croplands in semi-arid regions （e.g. Gansu and Inner Mongolia）, which was attributed to the well-developed drip irrigation technology in oases. Desert and Gobi ecosystems were slightly vulnerable to climate change during the past several decades. The assessment results, as revealed in this study, can provide a reference for taking appropriate actions to protect the ecosystems in western China.
基金financially supported by the National Basic Research Program of China(Grants No.2006CB403202)
文摘This study presents bulk chemical compositions of the Tongmuling soil profile, which developed on dolostone, and the overlying strata covering the bedrock in the central Guizhou province(southern China). The chemical weathering characteristics of the studied profile were investigated and the inheritance relationships between the terra rossa and overlying strata were discussed. The results show that there is no remarkable variation in the major elements and weathering indices from the rock–soil interface to the topsoil, indicating that the studied profile was not typical for in situ crustal chemical weathering. The terra rossa were mainly composed of Si O_2, Al_2O_3 and Fe_2O_3. Compared with the insoluble residues and overlying strata, the terra rossa are characterized by an enrichment of Y and Cs and depletion of Ba and Sr. The subsoil shows a notable Ce negative anomaly, characterized by heavy rare earth element enrichment(L/H = 1.55–3.74), whereas the topsoil shows a positive Ce anomaly with light rare earth element enrichment(L/H = 5.93–9.14). According to Laterite-forming capacity estimates, the terra rossa could not have only been formed from acid-insoluble residues from the bedrock; Al_2O_3 versus Fe_2O_3and Nb plotted against Ta show significant positive correlations between the terra rossa and overlying strata. The Eu/Eu* versusGd_N/Yb_Nand ternary diagrams for Sc, Th, Zr, and Ta suggest that the overlying strata could also provide parent materials for the genesis of terra rossa.
基金Project supported by the Science Research Foundation, Japan (No. 11460028).
文摘This study of Mikasa City in 2001, which analyzed N flow between N production and N load in seven agricultural and settlement subsystems, i.e., paddy, onion, wheat, vegetable, dairy, chicken, and citizen subsystems, aimed to compare N flow in each subsystem, to determine the main sources of the N load, and to evaluate the influence of agricultural production and food consumption on N cycling in a rural area. The results showed that in Mikasa city, 38.5% of the N load came from point sources and the remainder from non-point sources with intensive vegetable farming imparting a serious N load. Because of the internal N cycling in the dairy subsystem, chemical fertilizer application was reduced by 70.2%, and 23.72 Mg manure N was recycled to the field; therefore, the N utilization efficiency was raised from 18.1% to 35.1%. If all the manure N in the chicken subsystem was recycled, chemical fertilizer application would be reduced by 8.1% from the present level, and the point sources of N pollution would be reduced by 20.8%.
基金supported by National Natural Science Foundation of China (40730633)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-334)
文摘In this paper,10-day spatio-temporal response of vegetation to the change of temperature and precipitation in spring,summer,autumn and whole year during the period of 1998―2009 was analyzed based on the data of SPOT VEGETATION-NDVI and 10-day average temperature or precipitation from 54 meteorological stations in Xinjiang.The results show that the response of 10-day NDVI to temperature was more significant than that to precipitation,and the maximal response of vegetation to temperature and precipitation lagged for two 10-day periods.Seasonally,the effect of temperature and precipitation on vegetation NDVI was most marked in autumn,then in spring,and it was not significant in summer.The response of vegetation to 10-day change of meteorological factors was positive with a long affecting duration in spring,and it had a relatively short affecting duration in autumn and summer.Spatially,the 10-day maximal response of NDVI to temperature in northern Xinjiang was higher than that in southern Xinjiang.The correlation between the 10-day NDVI in whole year and the temperature in the 0-8th 10-day period was significantly higher than that between the annual NDVI and the annual temperature at all meteorological stations;the interannual change of NDVI was accordant well with the change of annual precipitation.However,the effect of precipitation within a year on NDVI was not strong.The results indicated that interannual change of temperature was not the dominant factor affecting the change of vegetation NDVI in Xinjiang,but the decrease of annual precipitation was the main factor resulting in the fluctuation of vegetation coverage.Ten-day average temperature was an important factor to promote vegetation growth in Xinjiang within a year,but the effect of precipitation on vegetation growth within a year was not strong.
基金supported by the Grant-in-Aid for Scientific Research of Japan Society for the Promotion of Science (JSPS KAKENHI) (Grant Nos.80378918,26292077)
文摘Although information regarding the initiation processes of debris flows is important for the development of mitigation measures,field data regarding these processes are scarce.We conducted field observations of debris-flow initiation processes in the upper Ichinosawa catchment of the Ohya landslide,central Japan.On 19 June 2012,our videocamera monitoring systems recorded the moment of debris-flow initiation on channel deposits(nine surges) and talus slopes(eight surges).The initiation mechanisms of these surges were classified into three types by analyzing the video images: erosion by the surface flow,movement of deposits as a mass,and upward development of the fluid area.The first type was associated with the progress of surface flow from the upper stream on unsaturated channel deposits.The second type was likely caused by an increase in the pore water pressure associated with the rising in the groundwater level in channel deposits;a continuous water supply from the upper stream by the surface flow might have induced this saturation.The third type was associated with changes in the downstream topography caused by erosion.The flow velocity of most surges was less than 3 m s^(-1) and they usually stopped within 100 m from the initiation point.Surges with abundant pore fluid had a higher flow velocity(about 3- 5 m s^(-1)) and could travel for alonger duration.Our observations indicate that the surface flow plays an important role in the initiation of debris flows on channel deposits and talus slopes.
