Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and...Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.展开更多
The main purpose of using geothermal energy piles(GEPs)is to enable the exploitation of geothermal energy for meeting the heating/cooling demands of buildings efficiently.However,the installation process of convention...The main purpose of using geothermal energy piles(GEPs)is to enable the exploitation of geothermal energy for meeting the heating/cooling demands of buildings efficiently.However,the installation process of conventional GEPs is inconvenient compared with that of traditional foundation piles.The pre-bored grouted planted geothermal energy pile(PGP GEP)is an innovative technology to simplify the installation process.Most investigations of in-situ experiments for conventional GEPs have focused on summer conditions.An in-situ test for a PGP GEP was conducted to analyze the temperature changes and thermo-mechanical characteristics under winter conditions.The results show that the average temperature of the pile decreased by 5.1℃,and the pile exhibited a general trend of high temperatures at both ends and low temperatures in the middle.In mechanics,strong pile end restraints resulted in smaller observed axial strain and higher axial thermal-induced force in the pile ends than at the middle of the pile.展开更多
During the winter of 2023/24,three distinct snowfall events occurred in eastern China,significantly impacting agriculture and transportation.The ability to provide subseasonal predictions with lead times beyond the we...During the winter of 2023/24,three distinct snowfall events occurred in eastern China,significantly impacting agriculture and transportation.The ability to provide subseasonal predictions with lead times beyond the weather timescale(longer than one week)is essential for effective disaster prevention and mitigation.Here,we assess the prediction skills of three subseasonal to seasonal(S2S)models from the S2S Prediction project regarding the three snowfall processes during the 2023/24 winter season,and identify the key sources of predictability for such events occurring over eastern China.The surface air temperature(SAT)and precipitation distribution for the three snowfall processes were successfully reproduced up to a lead time of 10–15 and 10 days,respectively.Since the skill in predicting snowfall is reliant on both SAT and precipitation predictions,all three S2S models therefore failed to predict the three snowfall processes beyond the weather timescale.The capacity in capturing Eurasian midlatitude transient Rossby waves and tropical convection anomalies determines the ability of the models to predict snowfall;inaccuracies in modeling these circulation systems result in an underestimation of SAT and precipitation anomalies beyond 15 and 10 days,respectively.Singular value decomposition analysis based on winter seasons from 1991/92 to 2023/24 further identified the coupling modes that exist between Eurasian midlatitude Rossby waves and SAT over eastern China,as well as between tropical convection and precipitation over the same region.These findings suggest that the configurations of tropical and extratropical signals provide universal subseasonal predictability sources for winter snowfall over eastern China.展开更多
As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline i...As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline ice and snow form a celestial winter realm.Amid the biting seasonal winds,o month-long New Year celebration brings one o deep,heartfelt warmth.Rarely witnessed elsewhere in the world,this collection of New Year customs stands as both a cultural marvel and a warm gift that the plateau bestows upon the depths of winter.展开更多
Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its s...Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.Products such as snowboards,ski goggles,and ski poles are drawing an increasing number of merchants worldwide for purchases.展开更多
In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible plat...In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.展开更多
In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The u...In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The undocking clearance of the HYSY 228 is smaller than 1 m;therefore,the barge shows highly nonlinear hydrodynamic characteristics,and it is difficult to be accurately simulated by numerical analysis.Thus,it is necessary to obtain the hydrodynamic characteristics and laws of the float-over barge at different water depths by using tank model test,to provide some reference and guidance for float-over operations in shallow water.展开更多
In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated...In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.展开更多
In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of inc...In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.展开更多
Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed so...Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed sowing on the GY and WUE are unclear. Therefore, a two-year field experiment was conducted during the 2021–2023 winter wheat growing seasons with a total six treatments: rain-fed(RF), conventional irrigation(CI) and micro-sprinkler irrigation(MI), as well as topsoil compaction after seed sowing under these three irrigation methods(RFC, CIC, and MIC). The results in the two years indicated that MI significantly increased GY compared to CI and RF, by averages of 17.9 and 42.1%, respectively. The increase in GY of MI was due to its significant increases in the number of spikes, kernels per spike, and grain weight. The chlorophyll concentration in flag leaves of MI after the anthesis stage maintained higher levels than with CI and RF, and was the lowest in RF. This was due to the dramatically enhanced catalase and peroxidase activities and lower malondialdehyde content under MI. Compared with RF and CI, MI significantly promoted dry matter remobilization and production after anthesis, as well as its contribution to GY. In addition, MI significantly boosted root growth, and root activity during the grain-filling stage was remarkably enhanced compared to CI and RF. In 2021–2022, there was no significant difference in WUE between MI and RF, but the WUE of RF was significantly lower than that of MI in 2022–2023. However, the WUE in MI was significantly improved compared to CI, and it increased by averages of 15.1 and 17.6% for the two years. Topsoil compaction significantly increased GY and WUE under rain-fed conditions due to improved spike numbers and dry matter production. Overall, topsoil compaction is advisable for enhancing GY and WUE in rain-fed conditions, whereas micro-sprinkler irrigation can be adopted to simultaneously achieve high GY and WUE in the HP.展开更多
Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two ...Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.展开更多
Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implement...Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implemented the Pilot Policy on Clean Winter Heating in Northern China,aiming to achieve high central heating coverage and cleaner energy consumption.Studying the effects of this policy can help promote its implementation and serve as a reference for effective adjustment of the contents in the future.However,few studies have investigated this policy and its carbon reduction effects,and most focus on the provincial or city levels.Therefore,this paper considers the policy’s influence on air pollution and carbon emissions at the county level to provide a precise and comprehensive assessment of the policy effects.We use panel data from 1290 counties in 15 provinces in Northern China from 2014 to 2021,applying a multiperiod difference-in-differences model to quantify the impact of the policy on carbon emissions and air quality in the pilot area.We then conduct a series of tests to demonstrate the robustness of the results and analyze the mechanisms of the policy effects from two perspectives,namely,central heating and natural gas use,through a mediating effect model.Finally,we examine the heterogeneity of policy effects between counties based on geographic location and per capita income levels of rural residents through a moderating effect model.The results reveal that the policy significantly reduces air pollution and carbon emissions in the pilot area by increasing the central heating area and natural gas use.Compared with the central and western regions in the north and areas with low-income rural residents,the policy effects in the eastern regions in the north and areas with high-income rural residents are more pronounced.展开更多
The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skil...The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.展开更多
The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arc...The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arctic sea ice and the SCSWM is investigated.The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector,i.e.,the Sea of Okhotsk and western Bering Sea.This link persists throughout the cold season,peaks when sea ice precedes the SCSWM by one month,and is independent of ENSO.North Pacific sea-ice loss weakens the meridional temperature gradient(MTG)and vertical wind shear in midlatitudes,reducing baroclinic eddy formation.Given the reduced zonal wind according to the thermal wind relation,the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation.This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N,which intensifies the divergent component of the SCSWM.The divergent northerly anomalies also lead to cold advection and subtropical cooling.The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward,creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM.These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM,holding substantial implications for the predictability of the SCSWM.展开更多
Just picture yourself sipping on a steaming cup of mi lk tea,snowflakes falling gently from the sky.In the distance,mountains blanketed in pure white stretch as far as the eye can see,glimmering like diamonds under th...Just picture yourself sipping on a steaming cup of mi lk tea,snowflakes falling gently from the sky.In the distance,mountains blanketed in pure white stretch as far as the eye can see,glimmering like diamonds under the winter sun.Welcome to Altay,a hidden treasure in China’s Xinjiang autonomous region.Nestled in the northwest,this prefecture has long been an attractive place for culture and leisure alike.This unique location has been shaped into a fascinating blend of influences,where yurts stand alongside modern buildings,and traditional nomadic heritage coexists with contemporary life.展开更多
1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this...1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.展开更多
In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads he...In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.展开更多
The winter holiday is almost over.It was a wonderful time full of fun and interesting things.I helped my parents do housework.1 cleaned the rooms,washed the clothes,and rooked simple meals.It made my parents happy and...The winter holiday is almost over.It was a wonderful time full of fun and interesting things.I helped my parents do housework.1 cleaned the rooms,washed the clothes,and rooked simple meals.It made my parents happy and I also learned how to look after myself.I love reading.During the winter holiday,I spent a lot of time reading different kinds of hooks.展开更多
文摘Yiwu merchants ride a winter sports boom as“Made in China”gear heats up the global economy Yiwu,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.
文摘The main purpose of using geothermal energy piles(GEPs)is to enable the exploitation of geothermal energy for meeting the heating/cooling demands of buildings efficiently.However,the installation process of conventional GEPs is inconvenient compared with that of traditional foundation piles.The pre-bored grouted planted geothermal energy pile(PGP GEP)is an innovative technology to simplify the installation process.Most investigations of in-situ experiments for conventional GEPs have focused on summer conditions.An in-situ test for a PGP GEP was conducted to analyze the temperature changes and thermo-mechanical characteristics under winter conditions.The results show that the average temperature of the pile decreased by 5.1℃,and the pile exhibited a general trend of high temperatures at both ends and low temperatures in the middle.In mechanics,strong pile end restraints resulted in smaller observed axial strain and higher axial thermal-induced force in the pile ends than at the middle of the pile.
基金supported by the National Key R&D Program of China(Grant No.2022YFF0801702)the Natural Science Foundation of Jiangsu Province(Grant No.BK20250045&BK20231110)the China Meteorological Administration Innovation and Development Project(Grant No.CXFZ2025Q007).
文摘During the winter of 2023/24,three distinct snowfall events occurred in eastern China,significantly impacting agriculture and transportation.The ability to provide subseasonal predictions with lead times beyond the weather timescale(longer than one week)is essential for effective disaster prevention and mitigation.Here,we assess the prediction skills of three subseasonal to seasonal(S2S)models from the S2S Prediction project regarding the three snowfall processes during the 2023/24 winter season,and identify the key sources of predictability for such events occurring over eastern China.The surface air temperature(SAT)and precipitation distribution for the three snowfall processes were successfully reproduced up to a lead time of 10–15 and 10 days,respectively.Since the skill in predicting snowfall is reliant on both SAT and precipitation predictions,all three S2S models therefore failed to predict the three snowfall processes beyond the weather timescale.The capacity in capturing Eurasian midlatitude transient Rossby waves and tropical convection anomalies determines the ability of the models to predict snowfall;inaccuracies in modeling these circulation systems result in an underestimation of SAT and precipitation anomalies beyond 15 and 10 days,respectively.Singular value decomposition analysis based on winter seasons from 1991/92 to 2023/24 further identified the coupling modes that exist between Eurasian midlatitude Rossby waves and SAT over eastern China,as well as between tropical convection and precipitation over the same region.These findings suggest that the configurations of tropical and extratropical signals provide universal subseasonal predictability sources for winter snowfall over eastern China.
文摘As the wheel of time turns toward the year's end and the beginning of the new year,the snow-kissed land of Xizang gracefully unveils its grandeur and offers a feast of wonders for all to explore.Here,crystalline ice and snow form a celestial winter realm.Amid the biting seasonal winds,o month-long New Year celebration brings one o deep,heartfelt warmth.Rarely witnessed elsewhere in the world,this collection of New Year customs stands as both a cultural marvel and a warm gift that the plateau bestows upon the depths of winter.
文摘Yiwu merchants ride a winter sports boom as“Made in China”winter gear heats up the global economy.YIWU,located in east China’s Zhejiang Province,is globally renowned as a hub for small commodities.This winter,its snow and ice sports products are generating a surge in business.Products such as snowboards,ski goggles,and ski poles are drawing an increasing number of merchants worldwide for purchases.
基金the National Natural Science Foundation of China(No.U20A20328).
文摘In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were investigated.First,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was performed.Relevant hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow theory.The results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling effect.According to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was considered.Furthermore,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were analyzed.Motion analysis revealed good agreement among the surge,sway,and yaw motions of the two floating bodies.However,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also observed.Therefore,excessive constraints should be added between the two floating bodies during construction to ensure construction safety.The numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 m.During construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.
文摘In this study,the Jinzhou 9-3 CEPD float-over installation project was investigated.During the undocking condition,the water depth of the motion path of the working barge gradually changed from 10.31 m to 9.41 m.The undocking clearance of the HYSY 228 is smaller than 1 m;therefore,the barge shows highly nonlinear hydrodynamic characteristics,and it is difficult to be accurately simulated by numerical analysis.Thus,it is necessary to obtain the hydrodynamic characteristics and laws of the float-over barge at different water depths by using tank model test,to provide some reference and guidance for float-over operations in shallow water.
基金supported by Marine Engineering Equipment Scientific Research Project of Ministry of Industry and Information Technology of PRC and the Application of float-over installation simulation in Wangchang Project of CNOOC Technology ProjectThe Fundamental Research Funds for the Central Universities(HEUCF170102)
文摘In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.
基金sponsored by POGC (Pars Oil and Gas Company,No.132 "Investigation of Structural Health Monitoring of Steel Jacket Offshore Platforms")The financial support of POGC is gratefully acknowledged
文摘In this paper, the seismic response of a newly designed steel jacket offshore platform with a float over deck （FOD） system in the Persian Gulf was investigated through incremental dynamic analysis. Comparison of incremental dynamic analysis results for both directions of the platform shows that the lateral strength of the platform in the float over direction is less than its lateral strength in other direction. Dynamic characteristics measurement of a scale model of platform was also performed using forced vibration tests. From experimental measurement of the scaled model, it was observed that dynamic characteristic of the platform is different in the float over direction compared to the other direction. Therefore, a new offshore installed bracing system for the float over direction was proposed for improvement of seismic performance of this type of platform. Finally, the structure with the modified system was assessed using the probabilistic seismic assessment method as well as experimental measurement of its dynamic characteristics. It was observed that the proposed offshore installed bracing system improves the performance of platforms subjected to strong ground motion.
基金funding from the Scientific Research Program of the Higher Educational Institutions in Anhui Province, China (2023AH050986)the Natural Science Foundation of Anhui Province, China (240805MC063)+1 种基金the National Natural Science Foundation of China (32172119)the Talent Introduction Project of Anhui Agricultural University, China (rc312212 and yj2019-01)。
文摘Increasing the grain yield(GY) and water use efficiency(WUE) of winter wheat in the Huaibei Plain(HP), China are essential. However, the effects of micro-sprinkler irrigation and topsoil compaction after wheat seed sowing on the GY and WUE are unclear. Therefore, a two-year field experiment was conducted during the 2021–2023 winter wheat growing seasons with a total six treatments: rain-fed(RF), conventional irrigation(CI) and micro-sprinkler irrigation(MI), as well as topsoil compaction after seed sowing under these three irrigation methods(RFC, CIC, and MIC). The results in the two years indicated that MI significantly increased GY compared to CI and RF, by averages of 17.9 and 42.1%, respectively. The increase in GY of MI was due to its significant increases in the number of spikes, kernels per spike, and grain weight. The chlorophyll concentration in flag leaves of MI after the anthesis stage maintained higher levels than with CI and RF, and was the lowest in RF. This was due to the dramatically enhanced catalase and peroxidase activities and lower malondialdehyde content under MI. Compared with RF and CI, MI significantly promoted dry matter remobilization and production after anthesis, as well as its contribution to GY. In addition, MI significantly boosted root growth, and root activity during the grain-filling stage was remarkably enhanced compared to CI and RF. In 2021–2022, there was no significant difference in WUE between MI and RF, but the WUE of RF was significantly lower than that of MI in 2022–2023. However, the WUE in MI was significantly improved compared to CI, and it increased by averages of 15.1 and 17.6% for the two years. Topsoil compaction significantly increased GY and WUE under rain-fed conditions due to improved spike numbers and dry matter production. Overall, topsoil compaction is advisable for enhancing GY and WUE in rain-fed conditions, whereas micro-sprinkler irrigation can be adopted to simultaneously achieve high GY and WUE in the HP.
基金supported by National Key R&D Program of China(2022YFD2000100)National Natural Science Foundation of China(42401400)Zhejiang Provincial Key Research and Development Program(2023C02018).
文摘Yellow rust(Puccinia striiformis f.sp.Tritici,YR)and fusarium head blight(Fusarium graminearum,FHB)are the two main diseases affecting wheat in the main grain-producing areas of East China,which is common for the two diseases to appear simultaneously in some main production areas.It is necessary to discriminate wheat YR and FHB at the regional scale to accurately locate the disease in space,conduct detailed disease severity monitoring,and scientific control.Four images on different dates were acquired from Sentinel-2,Landsat-8,and Gaofen-1 during the critical period of winter wheat,and 22 remote sensing features that characterize the wheat growth status were then calculated.Meanwhile,6 meteorological parameters that reflect the wheat phenological information were also obtained by combining the site meteorological data and spatial interpolation technology.Then,the principal components(PCs)of comprehensive remote sensing and meteorological features were extracted with principal component analysis(PCA).The PCs-based discrimination models were established to map YR and FHB damage using the random forest(RF)and backpropagation neural network(BPNN).The models’performance was verified based on the disease field truth data(57 plots during the filling period)and 5-fold cross-validation.The results revealed that the PCs obtained after PCA dimensionality reduction outperformed the initial features(IFs)from remote sensing and meteorology in discriminating between the two diseases.Compared to the IFs,the average area under the curve for both micro-average and macro-average ROC curves increased by 0.07 in the PCs-based RF models and increased by 0.16 and 0.13,respectively,in the PCs-based BPNN models.Notably,the PCs-based BPNN discrimination model emerged as the most effective,achieving an overall accuracy of 83.9%.Our proposed discrimination model for wheat YR and FHB,coupled with multi-source remote sensing images and meteorological data,overcomes the limitations of a single-sensor and single-phase remote sensing information in multiple stress discrimination in cloudy and rainy areas.It performs well in revealing the damage spatial distribution of the two diseases at a regional scale,providing a basis for detailed disease severity monitoring,and scientific prevention and control.
基金supported by the National Social Science Fund of China[Grant No.21BGL181]to Yan Chen.
文摘Coal dependence and inefficient decentralized heating have significantly increased China’s energy consumption for winter heating,increasing air pollution and exacerbating the greenhouse effect.In 2017,China implemented the Pilot Policy on Clean Winter Heating in Northern China,aiming to achieve high central heating coverage and cleaner energy consumption.Studying the effects of this policy can help promote its implementation and serve as a reference for effective adjustment of the contents in the future.However,few studies have investigated this policy and its carbon reduction effects,and most focus on the provincial or city levels.Therefore,this paper considers the policy’s influence on air pollution and carbon emissions at the county level to provide a precise and comprehensive assessment of the policy effects.We use panel data from 1290 counties in 15 provinces in Northern China from 2014 to 2021,applying a multiperiod difference-in-differences model to quantify the impact of the policy on carbon emissions and air quality in the pilot area.We then conduct a series of tests to demonstrate the robustness of the results and analyze the mechanisms of the policy effects from two perspectives,namely,central heating and natural gas use,through a mediating effect model.Finally,we examine the heterogeneity of policy effects between counties based on geographic location and per capita income levels of rural residents through a moderating effect model.The results reveal that the policy significantly reduces air pollution and carbon emissions in the pilot area by increasing the central heating area and natural gas use.Compared with the central and western regions in the north and areas with low-income rural residents,the policy effects in the eastern regions in the north and areas with high-income rural residents are more pronounced.
文摘The 9th Asian Winter Games were successfully held in Harbin,Heilongjiang Province,China,from February 7 to February 14,2025.This exciting event brought together athletes from all over Asia.They showed their great skills and strong will in different kinds of winter sports,such as skiing,skating and ice hockey.
基金supported by the National Key Research and Development Program of China[grant number 2022YFF0801701]the National Natural Science Foundation of China[grant number 42105017].
文摘The South China Sea winter monsoon(SCSWM),an integral component of the East Asian winter monsoon,connects extratropical and tropical regions.Utilizing ERA5 reanalysis and PAMIP simulations,the relationship between Arctic sea ice and the SCSWM is investigated.The authors reveal that its strongest relationship with Arctic sea ice occurs in the North Pacific sector,i.e.,the Sea of Okhotsk and western Bering Sea.This link persists throughout the cold season,peaks when sea ice precedes the SCSWM by one month,and is independent of ENSO.North Pacific sea-ice loss weakens the meridional temperature gradient(MTG)and vertical wind shear in midlatitudes,reducing baroclinic eddy formation.Given the reduced zonal wind according to the thermal wind relation,the reduced wave activity flux in the upper troposphere must be balanced by equatorward wind based on the quasi-geostrophic momentum equation.This generates an anomalous meridional overturning circulation with descent and low-level divergence around 30°N,which intensifies the divergent component of the SCSWM.The divergent northerly anomalies also lead to cold advection and subtropical cooling.The enhanced MTG due to the subtropical cooling and weakened MTG due to high-latitude warming closely tied to reduced North Pacific sea ice displace the westerly jet southward,creating cyclonic shears over the North Pacific and intensifying the rotational component of the SCSWM.These findings establish North Pacific sea ice as a non-ENSO driver of the SCSWM,holding substantial implications for the predictability of the SCSWM.
文摘Just picture yourself sipping on a steaming cup of mi lk tea,snowflakes falling gently from the sky.In the distance,mountains blanketed in pure white stretch as far as the eye can see,glimmering like diamonds under the winter sun.Welcome to Altay,a hidden treasure in China’s Xinjiang autonomous region.Nestled in the northwest,this prefecture has long been an attractive place for culture and leisure alike.This unique location has been shaped into a fascinating blend of influences,where yurts stand alongside modern buildings,and traditional nomadic heritage coexists with contemporary life.
文摘1 Trees don't create their own heat like mammals do,and they don't have warm shelters or fur coats.So how do they survive the deep freeze of winter?In a way they do hibernate(冬眠)like bears—but in trees this is called dormancy and it's pretty amazing.
文摘In winter,the weather is usually cold and everything seems a bit dull.Butthe sun in winter is special.When the sun shines brightly in the clear blue sky,it brings warm(1)to thecold world.The golden sunlight spreads here and there and it makes the whitesnow shine like diamonds.Although the trees are usually bare in winter,but(2)they look beautiful with the sunlight falling on them.
文摘The winter holiday is almost over.It was a wonderful time full of fun and interesting things.I helped my parents do housework.1 cleaned the rooms,washed the clothes,and rooked simple meals.It made my parents happy and I also learned how to look after myself.I love reading.During the winter holiday,I spent a lot of time reading different kinds of hooks.
