In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress ...In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.展开更多
The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We r...The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.展开更多
The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and...The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.展开更多
The cultural tradition of the Spring Festival has a long history,which is a profound embodiment of China's farming civilization and folk beliefs.The rituals and customs such as Worshipping the Kitchen God in the t...The cultural tradition of the Spring Festival has a long history,which is a profound embodiment of China's farming civilization and folk beliefs.The rituals and customs such as Worshipping the Kitchen God in the twelfth lunar month,putting up Spring Festival couplets,having family reunion dinner on Chinese New Year's Eve and temple fairs during the Spring Festival show the unique beliefs and values of the Chinese nation to bid farewell to the old and usher in the new and pray for reunion and happiness.展开更多
Spring returns with every thing growing.As the f irst high-level forum held after the Two Sessions,the China Development Forum(hereinaf ter refer red to as the Forum)brought together Chinese and foreign political and ...Spring returns with every thing growing.As the f irst high-level forum held after the Two Sessions,the China Development Forum(hereinaf ter refer red to as the Forum)brought together Chinese and foreign political and business people and became a weathervane for observing China’s economy.展开更多
Drought is one of the important stress factors affecting the growth and development processes of wheat in China's arid zones, which severely limits the yield. This study examined the impact of deficit irrigation o...Drought is one of the important stress factors affecting the growth and development processes of wheat in China's arid zones, which severely limits the yield. This study examined the impact of deficit irrigation on the flag leaf protection system and yield of drip-irrigated spring wheat during the growth stages in arid zones. In addition, this study aimed to determine the optimal water supply mode for efficient production under drip irrigation conditions and to provide technical support for water-saving and high-yield cultivation of drip-irrigated wheat. The experiment was conducted with a split plot design using the water-sensitive variety Xinchun 22(XC22) and the drought-tolerant variety Xinchun 6(XC6) as the main plots, while a fully irrigated control(CK, 75–80% FC, where FC is field water holding capacity), mild deficit(T1, 60–65% FC) and moderate deficit(T2, 45–50% FC) at the tillering stage, and mild deficit(J1, 60–65% FC) and moderate deficit(J2, 45–50% FC) at the jointing stage were used as the subplots. Systematic studies were conducted on the regulatory effects of deficit irrigation during the tillering and jointing stages on protective substances, membrane lipid metabolism, endogenous hormones in the flag leaf, and yield of spring wheat. Compared with treatments T2 and J2, treatments T1 and J1 were beneficial for increasing the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT), the levels of proline(Pro), indole-3-acetic acid(IAA), and zeatin riboside(ZR), and the ratios IAA/abscisic acid(ABA), ZR/ABA, IAA/ZR, and(IAA+ZR)/ABA, while reducing the levels of hydrogen peroxide(H2O2), superoxide anion radicals(O2–·), malondialdehyde(MDA), phosphatidic acid(PA), free fatty acids(FFA), ABA, phospholipase D(PLD), and lipoxygenase(LOX), alleviating flag leaf senescence, and increasing yield. Under treatment T1, the SOD, POD, CAT, and Pro levels of flag leaves in XC6 were 11.14, 8.08, 12.98, and 3.66% higher than those of treatment CK, and under treatment J1, they were 6.43, 4.49, 7.36, and 2.50% higher than those of treatment CK. Under treatment T1 in XC6, the IAA, ZR level of the flag leaf, spike number, grains per spike, 1,000-grain weight and yield were 10.50, 5.79, 3.10, 8.84, 3.78, and 10.52% higher than those of treatment CK, and under treatment J1, they were 5.36, 3.94, 2.40, 3.72, 1.37, and 4.46% higher than those of treatment CK. Compared with XC22, XC6 was more conducive to the improvement of flag leaf protective substances, IAA, ZR, dry matter weight, yield components and yield. The correlation analysis showed significant positive correlations between IAA and ZR with SOD, POD, CAT, proline, and yield. IAA and ZR promoted the enhancement of protective enzyme activities, thereby clearing reactive oxygen species to cope with the oxidative stress caused by drought and achieve the effect of delaying senescence. Principal component analysis showed that yield components and dry matter weight, had direct effects on yield. Mild deficiency during the tillering stage without water stress in other stages could effectively optimize yield components, not only achieving high yield while increasing protective substances, but also reducing the reactive oxygen species content. This strategy can be recommended as a water-saving and high-yield production mode for drip irrigation of spring wheat in Xinjiang, China.展开更多
基金Supported by the New-Cooperation Project of Japan Ministry of Economy,Trade and Industry
文摘In order to provide technical supports for designing a new type of spiral plate forming machine, FEM analysis and simulation were carried out based on pressing tests. Deformation, stress distribution, residual stress and spring back of the spiral plate were calculated. Relationships between the spiral pitch to inclination angle of the punch and die, material properties and thickness of the plate were analyzed. A data converter was developed and effectively used in the analysis. The results of FEM analysis and simulation have been applied to design the spiral plate forming machines.
基金National Key Research and Development Program of China,No.2023YFE0208100,No.2021YFC3000201Natural Science Foundation of Henan Province,No.232300420165。
文摘The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.
基金Under the auspices of National Natural Science Foundation of China(No.42201374,42071359)。
文摘The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology differ.Although previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains limited.In this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal forest.The estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario datasets.The sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime temperature.The LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN model.By incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is achieved.Furthermore,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study area.The simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate scenarios.This study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.
文摘The cultural tradition of the Spring Festival has a long history,which is a profound embodiment of China's farming civilization and folk beliefs.The rituals and customs such as Worshipping the Kitchen God in the twelfth lunar month,putting up Spring Festival couplets,having family reunion dinner on Chinese New Year's Eve and temple fairs during the Spring Festival show the unique beliefs and values of the Chinese nation to bid farewell to the old and usher in the new and pray for reunion and happiness.
文摘Spring returns with every thing growing.As the f irst high-level forum held after the Two Sessions,the China Development Forum(hereinaf ter refer red to as the Forum)brought together Chinese and foreign political and business people and became a weathervane for observing China’s economy.
基金made possible by the National Natural Science Foundation of China (32060422)。
文摘Drought is one of the important stress factors affecting the growth and development processes of wheat in China's arid zones, which severely limits the yield. This study examined the impact of deficit irrigation on the flag leaf protection system and yield of drip-irrigated spring wheat during the growth stages in arid zones. In addition, this study aimed to determine the optimal water supply mode for efficient production under drip irrigation conditions and to provide technical support for water-saving and high-yield cultivation of drip-irrigated wheat. The experiment was conducted with a split plot design using the water-sensitive variety Xinchun 22(XC22) and the drought-tolerant variety Xinchun 6(XC6) as the main plots, while a fully irrigated control(CK, 75–80% FC, where FC is field water holding capacity), mild deficit(T1, 60–65% FC) and moderate deficit(T2, 45–50% FC) at the tillering stage, and mild deficit(J1, 60–65% FC) and moderate deficit(J2, 45–50% FC) at the jointing stage were used as the subplots. Systematic studies were conducted on the regulatory effects of deficit irrigation during the tillering and jointing stages on protective substances, membrane lipid metabolism, endogenous hormones in the flag leaf, and yield of spring wheat. Compared with treatments T2 and J2, treatments T1 and J1 were beneficial for increasing the activities of superoxide dismutase(SOD), peroxidase(POD), and catalase(CAT), the levels of proline(Pro), indole-3-acetic acid(IAA), and zeatin riboside(ZR), and the ratios IAA/abscisic acid(ABA), ZR/ABA, IAA/ZR, and(IAA+ZR)/ABA, while reducing the levels of hydrogen peroxide(H2O2), superoxide anion radicals(O2–·), malondialdehyde(MDA), phosphatidic acid(PA), free fatty acids(FFA), ABA, phospholipase D(PLD), and lipoxygenase(LOX), alleviating flag leaf senescence, and increasing yield. Under treatment T1, the SOD, POD, CAT, and Pro levels of flag leaves in XC6 were 11.14, 8.08, 12.98, and 3.66% higher than those of treatment CK, and under treatment J1, they were 6.43, 4.49, 7.36, and 2.50% higher than those of treatment CK. Under treatment T1 in XC6, the IAA, ZR level of the flag leaf, spike number, grains per spike, 1,000-grain weight and yield were 10.50, 5.79, 3.10, 8.84, 3.78, and 10.52% higher than those of treatment CK, and under treatment J1, they were 5.36, 3.94, 2.40, 3.72, 1.37, and 4.46% higher than those of treatment CK. Compared with XC22, XC6 was more conducive to the improvement of flag leaf protective substances, IAA, ZR, dry matter weight, yield components and yield. The correlation analysis showed significant positive correlations between IAA and ZR with SOD, POD, CAT, proline, and yield. IAA and ZR promoted the enhancement of protective enzyme activities, thereby clearing reactive oxygen species to cope with the oxidative stress caused by drought and achieve the effect of delaying senescence. Principal component analysis showed that yield components and dry matter weight, had direct effects on yield. Mild deficiency during the tillering stage without water stress in other stages could effectively optimize yield components, not only achieving high yield while increasing protective substances, but also reducing the reactive oxygen species content. This strategy can be recommended as a water-saving and high-yield production mode for drip irrigation of spring wheat in Xinjiang, China.
