Despite the maturity of ensemble numerical weather prediction(NWP),the resulting forecasts are still,more often than not,under-dispersed.As such,forecast calibration tools have become popular.Among those tools,quantil...Despite the maturity of ensemble numerical weather prediction(NWP),the resulting forecasts are still,more often than not,under-dispersed.As such,forecast calibration tools have become popular.Among those tools,quantile regression(QR)is highly competitive in terms of both flexibility and predictive performance.Nevertheless,a long-standing problem of QR is quantile crossing,which greatly limits the interpretability of QR-calibrated forecasts.On this point,this study proposes a non-crossing quantile regression neural network(NCQRNN),for calibrating ensemble NWP forecasts into a set of reliable quantile forecasts without crossing.The overarching design principle of NCQRNN is to add on top of the conventional QRNN structure another hidden layer,which imposes a non-decreasing mapping between the combined output from nodes of the last hidden layer to the nodes of the output layer,through a triangular weight matrix with positive entries.The empirical part of the work considers a solar irradiance case study,in which four years of ensemble irradiance forecasts at seven locations,issued by the European Centre for Medium-Range Weather Forecasts,are calibrated via NCQRNN,as well as via an eclectic mix of benchmarking models,ranging from the naïve climatology to the state-of-the-art deep-learning and other non-crossing models.Formal and stringent forecast verification suggests that the forecasts post-processed via NCQRNN attain the maximum sharpness subject to calibration,amongst all competitors.Furthermore,the proposed conception to resolve quantile crossing is remarkably simple yet general,and thus has broad applicability as it can be integrated with many shallow-and deep-learning-based neural networks.展开更多
未来降水量的变化会改变草地对水资源的利用情况,影响植物内部养分循环。为了理解植物叶片氮回收特征对降水量变化的响应规律,本研究以5种内蒙古荒漠草原优势植物为研究对象,通过模拟降水试验(减水50%、自然降水、增水50%和增水100%),...未来降水量的变化会改变草地对水资源的利用情况,影响植物内部养分循环。为了理解植物叶片氮回收特征对降水量变化的响应规律,本研究以5种内蒙古荒漠草原优势植物为研究对象,通过模拟降水试验(减水50%、自然降水、增水50%和增水100%),分析了降水量变化对土壤水分含量、土壤有效氮(Nitrogen,N)含量、植物叶片N浓度、N回收效率(Nitrogen resorption efficiency,NRE)的影响。结果表明:与自然降水相比,增水100%显著增加了土壤水分含量、地上生物量和植物的NRE,显著降低了土壤有效N浓度、绿叶和枯叶中N浓度;而减水50%显著降低了土壤水分含量,增加了土壤有效N,降低了地上生物量,对绿叶和枯叶N浓度没有显著影响,降低了短花针茅(Stipa brevi flora)的NRE;植物NRE与枯片中的N浓度呈显著负相关关系。综上,增水通过影响土壤水分含量以及叶片N浓度间接降低了荒漠草原优势植物叶片的NRE。展开更多
At present,there are many studies on the residual stress field and plastic strain field introduced by surface strengthening,which can well hinder the initiation of early fatigue cracks and delay the propagation of fat...At present,there are many studies on the residual stress field and plastic strain field introduced by surface strengthening,which can well hinder the initiation of early fatigue cracks and delay the propagation of fatigue cracks.However,there are few studies on the effects of these key factors on fretting wear.In the paper,shot-peening(SP)and ultrasonic surface rolling process(USRP)were performed on Ti-6Al-4V plate specimens.The surface hardness and residual stresses of the material were tested by vickers indenter and X-ray diffraction residual stress analyzer.Microhardness were measured by HXD-1000MC/CD micro Vickers hardness tester.The effects of different surface strengthening on its fretting fatigue properties were verified by fretting fatigue experiments.The fretting fatigue fracture surface and wear morphology of the specimens were studied and analyzed by means of microscopic observation,and the mechanism of improving fretting fatigue life by surface strengthening process was further explained.After USRP treatment,the surface roughness of Ti-6Al-4V is significantly improved.In addition,the microhardness of the specimen after SP reaches the maximum at 80μm from the surface,which is about 123%higher than that of the AsR specimen.After USRP,it reaches the maximum at 150μm from the surface,which is about 128%higher than that of AsR specimen.It is also found that the residual compressive stress of the specimens treated by USRP and SP increases first and then decreases with the depth direction,and the residual stress reaches the maximum on the sub surface.The USRP specimen reaches the maximum value at 0.18 mm,about−550 MPa,while the SP specimen reaches the maximum value at 0.1 mm,about−380 MPa.The fretting fatigue life of Ti-6Al-4V effectively improved after USRP and SP.The surface integrity of specimens after USRP is the best,which has deeper residual compressive stress layer and more refined grain.In this paper,a fretting wear device is designed to carry out fretting fatigue experiments on specimens with different surface strengthening.展开更多
Surface roughness is one of the most important evaluation indexes in machine cutting. In order to analyze how the tool path affects the roughness of the surface after milling, series of simulations are implemented in ...Surface roughness is one of the most important evaluation indexes in machine cutting. In order to analyze how the tool path affects the roughness of the surface after milling, series of simulations are implemented in MasterCAM. We set up the same processing conditions with same parameters such as speed, material and feed rate etc. in these simulations, but different processing paths are used. We choose three paths: the parallel milling along the X-Y axis direction, the parallel milling along the Z-X or Z-Y axis direction and the streamline processing in the simulations. At the same time, end miller, arc miller and ball miller are respectively selected in the software. So there are totally 9 simulations of the milling process that are performed. Then the experimental cutting processes are performed correspondingly and the surface roughness and the accuracy are measured. The results show that the milling effect of the arc is better and the waste is minimal in the parallel milling along the Z-X or Z-Y axis direction with the end mills.展开更多
Objective:To observe the clinical therapeutic effect and safety on cancer-related fatigue(CRF)after chemotherapy treated with the reinforcing technique of acupuncture at Qihai(气海CV6),Guanyuan(关元CV4)and bilateral Z...Objective:To observe the clinical therapeutic effect and safety on cancer-related fatigue(CRF)after chemotherapy treated with the reinforcing technique of acupuncture at Qihai(气海CV6),Guanyuan(关元CV4)and bilateral Zusanli(足三里ST36)in the patients with colorectal cancer.Methods:A total of 61 cases of CRF after chemotherapy for colorectal cancer were included in the trial and randomized into a control group(30 cases)and an observation group(31 cases).The patients of the two groups all accepted the regular chemotherapy.Each duration of chemotherapy was 3 weeks.In the observation group,8 treatments with acupuncture were combined before chemotherapy and from the day 1 to 3 of chemotherapy separately,once daily,30 min in each time,for two courses totally.Acupoints included bilateral ST36,CV6 and CV4.Separately,1 day before the first cycle of chemotherapy,1 day before the second cycle of chemotherapy and in 3 weeks after the second cycle of chemotherapy,the score of Piper fatigue scale(PFS)and the score of the scale for quality of life(QOL)were adopted to evaluate the improvement degree of cancer-related fatigue.Results:Regarding PFS score,in 3-week followup after acupuncture treatment,compared with the control group,the mean value of the score of perception dimension was reduced obviously in the acupuncture treatment group,indicating the significant difference(P<0.05).Compared with the values before treatment,after acupuncture,the mean values of the scores in behavior dimension,affection dimension,perception dimension,cognition dimension and the overall score were all reduced obviously,indicating the significant differences in the treatment group(all P<0.05).But the differences were not significant in the control group in the mean values of the scores in behavior dimension,affection dimension,perception dimension and cognition dimension as well as in the overall score(all P>0.05).Regarding the score of QOL scale,compared with the control group,in the treatment group,the mean value of physical function score was increased significantly(P<0.05)and the mean values of the scores for overall health,fatigue and dyspnea were all reduced significantly,indicating the statistical differences(all P<0.05).Compared with the values before treatment,after treatment,the mean values of the scores for physical function,role function and social function,as well as the scores of overall health,fatigue and dyspnea were all different significantly in the treatment group(all P<0.05).But the mean values of the scores for each item as well as for overall health,fatigue and dyspnea were not different significantly in the control group(all P>0.05).Conclusion:In terms of the evaluation with PFS,acupuncture alleviates fatigue degree to the mild from the moderate in the patients with CRF,especially brings a positive effect on perception dimension,meaning the improvement of mental state.Regarding the evaluation of QOL scale,acupuncture improves overall health and physical function and alleviates fatigue and dyspnea.Acupuncture therapy has no obvious toxic side effect and achieves the definite therapeutic effect.展开更多
基金supported by the National Natural Science Foundation of China (Project No.42375192)the China Meteorological Administration Climate Change Special Program (CMA-CCSP+1 种基金Project No.QBZ202315)support by the Vector Stiftung through the Young Investigator Group"Artificial Intelligence for Probabilistic Weather Forecasting."
文摘Despite the maturity of ensemble numerical weather prediction(NWP),the resulting forecasts are still,more often than not,under-dispersed.As such,forecast calibration tools have become popular.Among those tools,quantile regression(QR)is highly competitive in terms of both flexibility and predictive performance.Nevertheless,a long-standing problem of QR is quantile crossing,which greatly limits the interpretability of QR-calibrated forecasts.On this point,this study proposes a non-crossing quantile regression neural network(NCQRNN),for calibrating ensemble NWP forecasts into a set of reliable quantile forecasts without crossing.The overarching design principle of NCQRNN is to add on top of the conventional QRNN structure another hidden layer,which imposes a non-decreasing mapping between the combined output from nodes of the last hidden layer to the nodes of the output layer,through a triangular weight matrix with positive entries.The empirical part of the work considers a solar irradiance case study,in which four years of ensemble irradiance forecasts at seven locations,issued by the European Centre for Medium-Range Weather Forecasts,are calibrated via NCQRNN,as well as via an eclectic mix of benchmarking models,ranging from the naïve climatology to the state-of-the-art deep-learning and other non-crossing models.Formal and stringent forecast verification suggests that the forecasts post-processed via NCQRNN attain the maximum sharpness subject to calibration,amongst all competitors.Furthermore,the proposed conception to resolve quantile crossing is remarkably simple yet general,and thus has broad applicability as it can be integrated with many shallow-and deep-learning-based neural networks.
文摘未来降水量的变化会改变草地对水资源的利用情况,影响植物内部养分循环。为了理解植物叶片氮回收特征对降水量变化的响应规律,本研究以5种内蒙古荒漠草原优势植物为研究对象,通过模拟降水试验(减水50%、自然降水、增水50%和增水100%),分析了降水量变化对土壤水分含量、土壤有效氮(Nitrogen,N)含量、植物叶片N浓度、N回收效率(Nitrogen resorption efficiency,NRE)的影响。结果表明:与自然降水相比,增水100%显著增加了土壤水分含量、地上生物量和植物的NRE,显著降低了土壤有效N浓度、绿叶和枯叶中N浓度;而减水50%显著降低了土壤水分含量,增加了土壤有效N,降低了地上生物量,对绿叶和枯叶N浓度没有显著影响,降低了短花针茅(Stipa brevi flora)的NRE;植物NRE与枯片中的N浓度呈显著负相关关系。综上,增水通过影响土壤水分含量以及叶片N浓度间接降低了荒漠草原优势植物叶片的NRE。
基金Supported by National Key Research and Development Project(Grant No.2018YFC1902400)Natural Science Foundation of Shanghai(Grant No.20ZR1415300).
文摘At present,there are many studies on the residual stress field and plastic strain field introduced by surface strengthening,which can well hinder the initiation of early fatigue cracks and delay the propagation of fatigue cracks.However,there are few studies on the effects of these key factors on fretting wear.In the paper,shot-peening(SP)and ultrasonic surface rolling process(USRP)were performed on Ti-6Al-4V plate specimens.The surface hardness and residual stresses of the material were tested by vickers indenter and X-ray diffraction residual stress analyzer.Microhardness were measured by HXD-1000MC/CD micro Vickers hardness tester.The effects of different surface strengthening on its fretting fatigue properties were verified by fretting fatigue experiments.The fretting fatigue fracture surface and wear morphology of the specimens were studied and analyzed by means of microscopic observation,and the mechanism of improving fretting fatigue life by surface strengthening process was further explained.After USRP treatment,the surface roughness of Ti-6Al-4V is significantly improved.In addition,the microhardness of the specimen after SP reaches the maximum at 80μm from the surface,which is about 123%higher than that of the AsR specimen.After USRP,it reaches the maximum at 150μm from the surface,which is about 128%higher than that of AsR specimen.It is also found that the residual compressive stress of the specimens treated by USRP and SP increases first and then decreases with the depth direction,and the residual stress reaches the maximum on the sub surface.The USRP specimen reaches the maximum value at 0.18 mm,about−550 MPa,while the SP specimen reaches the maximum value at 0.1 mm,about−380 MPa.The fretting fatigue life of Ti-6Al-4V effectively improved after USRP and SP.The surface integrity of specimens after USRP is the best,which has deeper residual compressive stress layer and more refined grain.In this paper,a fretting wear device is designed to carry out fretting fatigue experiments on specimens with different surface strengthening.
文摘Surface roughness is one of the most important evaluation indexes in machine cutting. In order to analyze how the tool path affects the roughness of the surface after milling, series of simulations are implemented in MasterCAM. We set up the same processing conditions with same parameters such as speed, material and feed rate etc. in these simulations, but different processing paths are used. We choose three paths: the parallel milling along the X-Y axis direction, the parallel milling along the Z-X or Z-Y axis direction and the streamline processing in the simulations. At the same time, end miller, arc miller and ball miller are respectively selected in the software. So there are totally 9 simulations of the milling process that are performed. Then the experimental cutting processes are performed correspondingly and the surface roughness and the accuracy are measured. The results show that the milling effect of the arc is better and the waste is minimal in the parallel milling along the Z-X or Z-Y axis direction with the end mills.
基金National Key Research and Development Plan:Research on academic viewpoints,characteristic diagnosis and treatment methods of the experiences of famous Chinese medicine physicians and the prevention and treatment of critical illness in eastern China:2018YFC1704102。
文摘Objective:To observe the clinical therapeutic effect and safety on cancer-related fatigue(CRF)after chemotherapy treated with the reinforcing technique of acupuncture at Qihai(气海CV6),Guanyuan(关元CV4)and bilateral Zusanli(足三里ST36)in the patients with colorectal cancer.Methods:A total of 61 cases of CRF after chemotherapy for colorectal cancer were included in the trial and randomized into a control group(30 cases)and an observation group(31 cases).The patients of the two groups all accepted the regular chemotherapy.Each duration of chemotherapy was 3 weeks.In the observation group,8 treatments with acupuncture were combined before chemotherapy and from the day 1 to 3 of chemotherapy separately,once daily,30 min in each time,for two courses totally.Acupoints included bilateral ST36,CV6 and CV4.Separately,1 day before the first cycle of chemotherapy,1 day before the second cycle of chemotherapy and in 3 weeks after the second cycle of chemotherapy,the score of Piper fatigue scale(PFS)and the score of the scale for quality of life(QOL)were adopted to evaluate the improvement degree of cancer-related fatigue.Results:Regarding PFS score,in 3-week followup after acupuncture treatment,compared with the control group,the mean value of the score of perception dimension was reduced obviously in the acupuncture treatment group,indicating the significant difference(P<0.05).Compared with the values before treatment,after acupuncture,the mean values of the scores in behavior dimension,affection dimension,perception dimension,cognition dimension and the overall score were all reduced obviously,indicating the significant differences in the treatment group(all P<0.05).But the differences were not significant in the control group in the mean values of the scores in behavior dimension,affection dimension,perception dimension and cognition dimension as well as in the overall score(all P>0.05).Regarding the score of QOL scale,compared with the control group,in the treatment group,the mean value of physical function score was increased significantly(P<0.05)and the mean values of the scores for overall health,fatigue and dyspnea were all reduced significantly,indicating the statistical differences(all P<0.05).Compared with the values before treatment,after treatment,the mean values of the scores for physical function,role function and social function,as well as the scores of overall health,fatigue and dyspnea were all different significantly in the treatment group(all P<0.05).But the mean values of the scores for each item as well as for overall health,fatigue and dyspnea were not different significantly in the control group(all P>0.05).Conclusion:In terms of the evaluation with PFS,acupuncture alleviates fatigue degree to the mild from the moderate in the patients with CRF,especially brings a positive effect on perception dimension,meaning the improvement of mental state.Regarding the evaluation of QOL scale,acupuncture improves overall health and physical function and alleviates fatigue and dyspnea.Acupuncture therapy has no obvious toxic side effect and achieves the definite therapeutic effect.
