Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological obse...Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological observational data in a period of two years as the reference, the maximum and minimum temperature predictions of Shenyang station from the European Center for Medium-Range Weather Forecasts (ECMWF) and national intelligent grid forecasts are objectively corrected by using wavelet analysis, sliding training and other technologies. The evaluation results show that the sliding training time window of the maximum temperature is smaller than that of the minimum temperature, and their difference is the largest in August, with a difference of 2.6 days. The objective correction product of maximum temperature shows a good performance in spring, while that of minimum temperature performs well throughout the whole year, with an accuracy improvement of 97% to 186%. The correction effect in the central plains is better than in the regions with complex terrain. As for the national intelligent grid forecasts, the objective correction products have shown positive skills in predicting the maximum temperatures in spring (the skill-score reaches 0.59) and in predicting the minimum temperature at most times of the year (the skill-score reaches 0.68).展开更多
【目的】加快蓝莓品种"康维尔"组培苗快繁速度。【方法】以"康维尔"茎段为外植体,研究了不同p H梯度、不同蔗糖浓度梯度以及3种结构相似的细胞分裂素对蓝莓试管苗增殖的影响。【结果】p H 6.0时的鲜重和增殖系数都...【目的】加快蓝莓品种"康维尔"组培苗快繁速度。【方法】以"康维尔"茎段为外植体,研究了不同p H梯度、不同蔗糖浓度梯度以及3种结构相似的细胞分裂素对蓝莓试管苗增殖的影响。【结果】p H 6.0时的鲜重和增殖系数都最高,说明蓝莓品种"康维尔"最适宜的酸碱度为6.0;当蔗糖浓度为25 g/L时,试管苗鲜重达到最大值,不再随蔗糖浓度增加而增加,蔗糖浓度25~30 g/L的增殖系数和苗高都无显著差异,因此出于成本的考虑,可选择25 g/L作为生产上使用的蔗糖浓度;使用反玉米素核苷的试管苗无论是在鲜重、增殖系数和苗高都明显高于反玉米素和玉米素,且使用反玉米素核苷的成本更低。【结论】蓝莓"康维尔"试管苗的最佳增殖培养基:LM基本培养基+25 g/L蔗糖+1 mg/L反玉米素核苷,p H 6.0。展开更多
以工业硅为原料,利用介质熔炼、定向凝固和电子束熔炼三种熔体处理技术对工业硅中的B、P和金属杂质进行了去除,制备出了99.9999%级多晶硅材料,其中,杂质B和P的含量分别低于0.20 ppmw(parts per million(weight),百万分之一质量),金属杂...以工业硅为原料,利用介质熔炼、定向凝固和电子束熔炼三种熔体处理技术对工业硅中的B、P和金属杂质进行了去除,制备出了99.9999%级多晶硅材料,其中,杂质B和P的含量分别低于0.20 ppmw(parts per million(weight),百万分之一质量),金属杂质总含量(TM)低于0.23 ppmw。研究发现,介质熔炼去除杂质B的过程中,熔体中发生氧化还原反应可以有效去除大部分的杂质Al和Ca;电子束熔炼过程中,利用饱和蒸气压原理可以有效去除挥发性杂质P、Al、Ca,同时降束诱导多晶硅定向凝固,可将其他金属杂质进一步去除。本研究通过各技术间的耦合除杂,减少了冶金法提纯多晶硅的工序,为连续化、规模化生产提供了技术支撑。展开更多
The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that me...The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that metformin, a commonlyused clinical drug for T2DM, attracts scholars’ attention because of its benefits inlowering the risk of developing CRC. Hence, we try to find the common groundsof initiation of T2DM and CRC and the reason why metformin reduces the risk ofCRC in patients with T2DM. We noticed consistent changes of gut microbiota,such as elevated Bacteroides, Prevotella and Bifidobacterium and depressedFirmicutes and Lactobacillus. Furthermore, many studies in recent years haveproved that the efficacy of metformin, such as improving blood glucose, dependson the gut microbiota. Coincidentally, the progression of CRC is inseparable fromthe contributions of gut microbiota. Therefore, we first proposed the concept ofthe metformin-gut microbiota–CRC (in T2DM) axis to explain the effect ofmetformin in reducing CRC in patients with T2DM. In this review, we elaboratedthe new concept and its potential clinical application value.展开更多
Mealybugs, such as Phenacoccus solenopsis, are highly sexually dimorphic. Winged adult males present such remarkable morphological differences from females that, to the untrained eye, conspecific adults of both sexes ...Mealybugs, such as Phenacoccus solenopsis, are highly sexually dimorphic. Winged adult males present such remarkable morphological differences from females that, to the untrained eye, conspecific adults of both sexes of P. solenopsis may be considered as two different insect species. A method to investigate sex-dimorphic mechanisms is by evaluating gene expression using RT-qPCR. However, the accuracy and consistency of this technique depend on the reference gene(s) selected. In this study, we analyzed the expression of 10 candidate reference genes in male and female P. solenopsis at different development stages, using common algorithms including the ?Ct method, NormFinder, geNorm, BestKeeper, and a web-based analysis tool, RefFinder. The results showed that EF1-β, RP-L32 and RP-18 S were selected as the most stable genes by both the ?Ct method and NormFinder; TUB-α was the most stable gene identified by BestKeeper; and RP-L40 and RP-L32 were the most stable genes ranked by geNorm. RefFinder, a comprehensive analysis software, ranked the ten genes and determined EF1-β and RP-L32 as the most suitable reference genes for the various developmental stages in male and female P. solenopsis. Furthermore, the two most suitable reference genes were validated by examining expression of the juvenile hormone acid O-methytransferase(JHAMT) gene. Results of the validation portion of the study showed that JHAMT expression was sex-biased towards males and exhibited a dynamic and classic expression pattern among the P. solenopsis developmental stages. The results can help further our knowledge on the molecular mechanisms underlying sexual dimorphic development in P. solenopsis.展开更多
The microstructure,mechanical properties and corrosion resistance of Zr-30%Ta and Zr-25%Ta-5%Ti alloy prepared by spark plasma sintering(SPS)technology were investigated.The experimental results showed that the Zr-Ta-...The microstructure,mechanical properties and corrosion resistance of Zr-30%Ta and Zr-25%Ta-5%Ti alloy prepared by spark plasma sintering(SPS)technology were investigated.The experimental results showed that the Zr-Ta-Ti alloys made by the SPS processing have a low level of porosity with the relative density of 96%−98%.The analyses of XRD and TEM revealed that the Zr-30Ta alloy consists ofα+βphase,and the Zr-25Ta-5Ti alloy belongs to the nearβtype alloy containing a small amount ofαandωphases.With the addition of Ti,the elastic modulus of the alloys was decreased from(99.5±7.2)GPa for Zr-30Ta alloy to(73.6±6.3)GPa for Zr-25Ta-5Ti alloy.Furthermore,it is shown that,in comparison to CP-Ti and Ti-6Al-4V alloy,the Zr-Ta-Ti alloy produced in this work offers an improved corrosion resistance due to the more stable ZrO2 and Ta2O5 generated in the passivation film on the surface of the alloys.This study demonstrates that Zr-Ta-Ti alloys are a promising candidate of novel metallic biomaterials.展开更多
【目的】为筛选有效防治韭蛆Bradysia odoriphaga Yang et Zhang的药剂及科学合理的施药方法。【方法】本试验充分抓住韭蛆喜湿这一生物学特性,采用两种不同的施药方法(单次定点淋根法和二次灌根法)评价8种药剂对韭蛆的防治效果。【结...【目的】为筛选有效防治韭蛆Bradysia odoriphaga Yang et Zhang的药剂及科学合理的施药方法。【方法】本试验充分抓住韭蛆喜湿这一生物学特性,采用两种不同的施药方法(单次定点淋根法和二次灌根法)评价8种药剂对韭蛆的防治效果。【结果】同种药剂不同的施药方法,二次灌根法在韭蛆防效、韭菜保苗率和韭菜增产率三方面均明显高于单次定点淋根法。同时,噻虫胺、噻虫嗪和吡虫啉3种药剂单独使用,或分别与辣根素混配,对韭蛆均表现出最佳的防治效果。【结论】本研究提出了一种科学合理的施药方法,对防治韭蛆具有重要的意义。展开更多
文摘Post-processing correction is an effective way to improve the model forecasting result. Especially, the machine learning methods have played increasingly important roles in recent years. Taking the meteorological observational data in a period of two years as the reference, the maximum and minimum temperature predictions of Shenyang station from the European Center for Medium-Range Weather Forecasts (ECMWF) and national intelligent grid forecasts are objectively corrected by using wavelet analysis, sliding training and other technologies. The evaluation results show that the sliding training time window of the maximum temperature is smaller than that of the minimum temperature, and their difference is the largest in August, with a difference of 2.6 days. The objective correction product of maximum temperature shows a good performance in spring, while that of minimum temperature performs well throughout the whole year, with an accuracy improvement of 97% to 186%. The correction effect in the central plains is better than in the regions with complex terrain. As for the national intelligent grid forecasts, the objective correction products have shown positive skills in predicting the maximum temperatures in spring (the skill-score reaches 0.59) and in predicting the minimum temperature at most times of the year (the skill-score reaches 0.68).
文摘以工业硅为原料,利用介质熔炼、定向凝固和电子束熔炼三种熔体处理技术对工业硅中的B、P和金属杂质进行了去除,制备出了99.9999%级多晶硅材料,其中,杂质B和P的含量分别低于0.20 ppmw(parts per million(weight),百万分之一质量),金属杂质总含量(TM)低于0.23 ppmw。研究发现,介质熔炼去除杂质B的过程中,熔体中发生氧化还原反应可以有效去除大部分的杂质Al和Ca;电子束熔炼过程中,利用饱和蒸气压原理可以有效去除挥发性杂质P、Al、Ca,同时降束诱导多晶硅定向凝固,可将其他金属杂质进一步去除。本研究通过各技术间的耦合除杂,减少了冶金法提纯多晶硅的工序,为连续化、规模化生产提供了技术支撑。
基金Supported by National NaturalScience Foundation of China, No.81573239.
文摘The prevalence of colorectal cancer (CRC) and type 2 diabetes mellitus (T2DM) isincreasing globally. It is rarely noticed that the incidence of CRC is higher inpatients with T2DM. What needs to be mentioned is that metformin, a commonlyused clinical drug for T2DM, attracts scholars’ attention because of its benefits inlowering the risk of developing CRC. Hence, we try to find the common groundsof initiation of T2DM and CRC and the reason why metformin reduces the risk ofCRC in patients with T2DM. We noticed consistent changes of gut microbiota,such as elevated Bacteroides, Prevotella and Bifidobacterium and depressedFirmicutes and Lactobacillus. Furthermore, many studies in recent years haveproved that the efficacy of metformin, such as improving blood glucose, dependson the gut microbiota. Coincidentally, the progression of CRC is inseparable fromthe contributions of gut microbiota. Therefore, we first proposed the concept ofthe metformin-gut microbiota–CRC (in T2DM) axis to explain the effect ofmetformin in reducing CRC in patients with T2DM. In this review, we elaboratedthe new concept and its potential clinical application value.
基金supported by the National Natural Science Foundation of China(31270580)the Key Research and Development Program of Zhejiang Province,China(2018C02036)+1 种基金the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2012BAD19B06)the Special Fund for Agro-scientific Research in the Public Interest of China(201103026)
文摘Mealybugs, such as Phenacoccus solenopsis, are highly sexually dimorphic. Winged adult males present such remarkable morphological differences from females that, to the untrained eye, conspecific adults of both sexes of P. solenopsis may be considered as two different insect species. A method to investigate sex-dimorphic mechanisms is by evaluating gene expression using RT-qPCR. However, the accuracy and consistency of this technique depend on the reference gene(s) selected. In this study, we analyzed the expression of 10 candidate reference genes in male and female P. solenopsis at different development stages, using common algorithms including the ?Ct method, NormFinder, geNorm, BestKeeper, and a web-based analysis tool, RefFinder. The results showed that EF1-β, RP-L32 and RP-18 S were selected as the most stable genes by both the ?Ct method and NormFinder; TUB-α was the most stable gene identified by BestKeeper; and RP-L40 and RP-L32 were the most stable genes ranked by geNorm. RefFinder, a comprehensive analysis software, ranked the ten genes and determined EF1-β and RP-L32 as the most suitable reference genes for the various developmental stages in male and female P. solenopsis. Furthermore, the two most suitable reference genes were validated by examining expression of the juvenile hormone acid O-methytransferase(JHAMT) gene. Results of the validation portion of the study showed that JHAMT expression was sex-biased towards males and exhibited a dynamic and classic expression pattern among the P. solenopsis developmental stages. The results can help further our knowledge on the molecular mechanisms underlying sexual dimorphic development in P. solenopsis.
基金Project(51404302)supported by the National Natural Science Foundation of ChinaProject(QJ2018003A)supported by the Youth Scientific Research Foundation of the Central South University of Forestry and Technology,China。
文摘The microstructure,mechanical properties and corrosion resistance of Zr-30%Ta and Zr-25%Ta-5%Ti alloy prepared by spark plasma sintering(SPS)technology were investigated.The experimental results showed that the Zr-Ta-Ti alloys made by the SPS processing have a low level of porosity with the relative density of 96%−98%.The analyses of XRD and TEM revealed that the Zr-30Ta alloy consists ofα+βphase,and the Zr-25Ta-5Ti alloy belongs to the nearβtype alloy containing a small amount ofαandωphases.With the addition of Ti,the elastic modulus of the alloys was decreased from(99.5±7.2)GPa for Zr-30Ta alloy to(73.6±6.3)GPa for Zr-25Ta-5Ti alloy.Furthermore,it is shown that,in comparison to CP-Ti and Ti-6Al-4V alloy,the Zr-Ta-Ti alloy produced in this work offers an improved corrosion resistance due to the more stable ZrO2 and Ta2O5 generated in the passivation film on the surface of the alloys.This study demonstrates that Zr-Ta-Ti alloys are a promising candidate of novel metallic biomaterials.
文摘【目的】为筛选有效防治韭蛆Bradysia odoriphaga Yang et Zhang的药剂及科学合理的施药方法。【方法】本试验充分抓住韭蛆喜湿这一生物学特性,采用两种不同的施药方法(单次定点淋根法和二次灌根法)评价8种药剂对韭蛆的防治效果。【结果】同种药剂不同的施药方法,二次灌根法在韭蛆防效、韭菜保苗率和韭菜增产率三方面均明显高于单次定点淋根法。同时,噻虫胺、噻虫嗪和吡虫啉3种药剂单独使用,或分别与辣根素混配,对韭蛆均表现出最佳的防治效果。【结论】本研究提出了一种科学合理的施药方法,对防治韭蛆具有重要的意义。
