检索结果-南通市图书馆

A new resveratrol tetramer from Caragana rosea

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2007年第1期18卷 69-72页

作者： Guo Xun yang chang qi Hu Department of Chemistry of Natural Products Fudan University Shanghai 200032 China

In a continual effort to search for any anti-HIV agent from traditional Chinese medicine, one new resveratrol tetramer, cararosinols B, was isolated from the ethanol extract of aerial parts of Caragana rosea. Its stru... 详细信息

关键词： Leguminosae Caragana rosea Stilbenoid Cararosinol B

Overhead supplemental far-red light stimulates tomato growth under intra-canopy lighting with LEDs

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2019年第1期18卷 62-69页

作者： ZHANG Ya-ting ZHANG Yu-qi yang qi-chang LI Tao Key Laboratory of Energy Conservation and Waste Management of Agricultural Structures Ministry of Agriculture and Rural Affairs/Institute of Environment and Sustainable Development in AgricultureChinese Academy of Agriculture Sciences

Far-red(FR) light regulates phytochrome-mediated morphological and physiological plant *** study aims to investigate how greenhouse tomato morphology and production response to different durations of FR light during daytime and at the end of day(EOD).High-wire tomato plants were grown under intra-canopy lighting consisting of red(peak wavelength at 640 nm) and blue(peak wavelength at 450 nm) light-emitting diodes(LEDs) with photosynthetic photon flux density(PPFD) of 144 μmol m–2 s–1 at 10 cm away from the lamps,and combined with overhead supplemental FR light(peak wavelength at 735 nm) with PPFD of 43 μmol m–2 s–1 at 20 cm below the *** were exposed to three durations of FR supplemental lighting including: 06:00–18:00(FR12),18:00–19:30(EOD-FR1.5),18:00–18:30(EOD-FR0.5),and control that without supplemental FR *** results showed that supplemental FR light significantly stimulated stem elongation thereby resulting in longer plants compared with the ***,FR light altered leaf morphology toward higher leaf length/width ratio and larger leaf *** altered plant architecture in FR supplemented plants led to a more homogeneous light distribution inside the *** plant biomass was increased by 9–16% under supplemental FR light in comparison with control,which led to 7–12% increase in ripe fruit *** sugar content of the ripe tomato fruit was slightly decreased by longer exposure of the plants to FR *** matter partitioning to different plant organs were not substantially affected by the FR light *** significant differences were observed among the three FR light treatments in plant morphology as well as yield and biomass *** conclude that under intra-canopy lighting,overhead supplemental FR light stimulates tomato growth and *** supplementary of EOD-FR0.5 is more favorable,as it consumes less electricity but induces similar effects on plant morphology and yield.

关键词： Solanum lycopersicum far-red light LEDs intro-canopy lighting morphology yield

在线全文

学校读者我要写书评

暂无评论

基于BERT模型的空管危险源文本数据挖掘

航空计算技术 2024年第4期54卷 89-93页

作者：杨昌其姜美岑林灵中国民用航空飞行学院四川广汉618000

由于危险源与安全隐患在民航安全管理工作中容易出现概念混淆和记录混乱的情况,根据双重预防机制管理规定,需要将两者区分开来。通过在ASIS系统上采集得到空管危险源控制清单作为研究对象,并对其进行相应的文本数据挖掘工作。根据危险... 详细信息

由于危险源与安全隐患在民航安全管理工作中容易出现概念混淆和记录混乱的情况,根据双重预防机制管理规定,需要将两者区分开来。通过在ASIS系统上采集得到空管危险源控制清单作为研究对象,并对其进行相应的文本数据挖掘工作。根据危险源与安全隐患特点构建相应的文本分类模型:首先通过文本清洗、去停用词、Jieba分词等对空管危险源控制清单进行预处理,然后基于BERT模型生成词向量,采用BERT-Base-Chinese预训练模型进行预训练,并对模型进行微调超参数,最后结合Softmax分类器得到分类结果。

关键词：文本分类数据挖掘 BERT模型危险源安全隐患

A new tetrastilbene from Caragana sinica

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2008年第6期19卷 711-715页

作者： Ke Jun Cheng Da You Ma Guo Xun yang chang qi Hu Department of Chemistry of Natural Products Fudan University Shanghai 200032 China

A new tetrastilbene named carasinol D （1） was isolated from the roots of Caragana sinica. Its structure was elucidated by spectroscopic analysis. Compound 1 was obtained from carasinol B （2） by an acid-catalyzed c... 详细信息

关键词： Caragana sinica Stilbenoids Carasinol D Carasinol B

A New Stilbene Tetramer from Caragana rosea

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第10期14卷 1048-1050页

作者： Guo Xun yang, chang qi HU School of Pharmacy, Fudan University, Shanghai 200032 School of Pharmacy Fudan University

Cararosinol A, a new stilbene tetramer, was isolated from Caragana rosea. Its structure has been established on the basis of spectroscopic evidence.

关键词： Caragana rosea Leguminase stilbene tetramer.

The effect of artificial solar spectrum on growth of cucumber and lettuce under controlled environment

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2020年第8期19卷 2027-2034页

作者： ZOU Jie ZHOU Cheng-bo XU Hong CHENG Rui-feng yang qi-chang LI Tao Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081P.R.China Sonneteck Technology Co. Ltd.Xiamen 361000P.R.China

Light-emitting diodes(LEDs)have been widely applied in the controlled environment agriculture,which are characterized by relatively narrow-band spectra and energetical *** recently,the spectrum of Sunlike LEDs has been engineered and it closely resembles solar spectrum in the range of photosynthetic active radiation(PAR,400–700 nm).To investigate how plant growth responses to the spectrum of Sunlike LEDs,cucumber and lettuce plants were cultivated and their responses were compared with the conventional white LEDs as well as composite of red and blue LEDs(RB,R/B ratio was 9:1).We observed that although Sunlike LEDs resulted in a longer stem in cucumber,dry weight and leaf area were similar as those under RB LEDs,and significantly higher than those under white ***,cucumber leaves grown under Sunlike and white LEDs showed higher photosynthetic capacity than those grown under RB *** lettuce,plants grown under Sunlike LEDs showed larger leaf area and higher dry weight than the other two ***,the leaf photosynthetic capacity of lettuce grown under Sunlike LEDs was the *** this context,the spectrum induced plant functions are ***,the three types of LEDs show distinct light spectra and they are different in many ***,it is difficult to attribute the different plant responses to certain specific light *** conclude that plants grown under Sunlike LEDs exhibit larger leaf area,which may be due to some specific spectrum distributions(such as more far-red radiation),and consequently are favorable for light interception and therefore result in greater production.

关键词： cucumber leaf photosynthesis lettuce plant morphology Sunlike LEDs

Selenium distribution and nitrate metabolism in hydroponic lettuce(Lactuca sativa L.): Effects of selenium forms and light spectra

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2020年第1期19卷 133-144页

作者： BIAN Zhong-hua LEI Bo CHENG Rui-feng WANG Yu LI Tao yang qi-chang Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081P.R.China School of Animal Rural and Environmental SciencesNottingham Trent UniversityBrackenhurst CampusNG250QFUK

A deficiency in selenium(Se) in the human diet is a worldwide problem. The intake of Se-rich vegetables can be a safe way to combat Se deficiency for humans. However, most leafy vegetables can accumulate a high content of nitrates, which poses a potential threat to human health. Light is an important environmental factor that regulates the uptake and distribution of mineral elements and nitrogen metabolism in plants. However, the effects of Se forms and light conditions, especially light spectra, on the uptake and translocation of Se and on nitrate reduction are poorly understood. In this study, lettuce(Lactuca sativa L.) was treated with exogenous Se applied as selenate(10 mmol L^-1) and selenite(0.5 mmol L^-1) and grown under five different light spectra: fluorescent light(FL), monochromatic red LED light(R), monochromatic blue LED light(B), and mixed red and blue LED light with a red to blue light ratio at 4(R/B=4), 8(R/B=8), and 12(R/B=12), respectively. The effects of light spectra and Se forms on plant growth, photosynthetic performance, Se accumulation and nitrate reduction were investigated. The results showed that the light spectra and Se forms had significant interactions for plant growth, foliar Se accumulation and nitrate reduction. The Se concentration and nitrate content in the leaves were negatively correlated with the percentage of red light from the light sources. Compared to Se applied as selenite, exogenous Se applied as selenate was more effective in reducing nitrate via promoting nitrate reductase and glutamate synthase activities. The lowest nitrate content and highest plant biomass were observed under R/B=8 for both the selenate and selenite treatments. The significant effect of the light spectra on the root concentration factor and translocation factor of Se resulted in marked variations in the Se concentrations in the roots and leaves. Compared with FL, red and blue LED light led to significant decreases in the foliar Se concentration. The r

关键词： selenium light spectra nitrates nitrogen metabolism enzymes LEDs Lactuca sativa L.

Spatial distribution of air temperature and relative humidity in the greenhouse as affected by external shading in arid climates

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2019年第12期18卷 2869-2882页

作者： Hesham AAhmed TONG Yu-xin yang qi-chang Abdulellah AAl-Faraj Ahmed MAbdel-Ghany Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081P.R.China Key Laboratory of Energy Conservation and Waste Management of Agricultural Structures Beijing 100081P.R.China Department of Agricultural Engineering College of Food and Agriculture SciencesKing Saud UniversityRiyadh 11451Saudi Arabia Department of Agricultural Engineering Faculty of AgricultureSana'a UniversitySana'a 2124Yemen

The effect of external roof shading on the spatial distribution of air temperature and relative humidity in a greenhouse(Tin and RHin) was evaluated under the arid climatic conditions of Riyadh City, Saudi Arabia. Two identical, evaporatively-cooled, single-span greenhouses were used in the experiment. One greenhouse was externally shaded(Gs) using a movable black plastic net(30% transmissivity), and the other greenhouse was kept without shading(Gc). Strawberry plants were cultivated in both greenhouses. The results showed that the spatial distribution of the Tin and RHin was significantly affected by the outside solar radiation and evaporative cooling operation. The regression analysis showed that when the outside solar radiation intensity increased from 200 to 800 W m–2, the Tin increased by 4.5℃ in the Gc and 2℃in the Gs, while the RHin decreased by 15% in the Gc and 5% in the Gs, respectively. Compared with those in the Gc, more uniformity in the spatial distribution of the Tin and RHin was observed in the Gs. The difference between the maximum and minimum Tin of 6.4℃ and the RHin of 10% was lower in the Gs than those in the Gc during the early morning. Around 2℃ difference in the Tin was shown between the area closed to the exhausted fans and the area closed to the cooling pad with the external shading. In an evaporatively-cooled greenhouse in arid regions, the variation of the Tin and RHin in the vertical direction and along the sidewalls was much higher than that in the horizontal direction. The average variation of the Tin and RHin in the vertical direction was 5.2℃ and 10% in the Gc and 5.5℃ and 13% in the Gs, respectively. The external shading improved the spatial distribution of the Tin and RHin and improved the cooling efficiency of the evaporative cooling system by 12%, since the transmitted solar radiation and accumulated thermal energy in the greenhouse were significantly reduced.

关键词： greenhouse temperature humidity distribution uniformity evaporative cooling shading arid climate

Realizing the excellent oxidation resistance of an environmental barrier coating through aluminum surface modification

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2024年第7期13卷 976-986页

作者： Lin Dong Wen-qi yang Lin Chen Guan-Jun yang chang-Jiu Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Xi’an Aerospace Engine Company Limited in China Aerospace Science and Technology Corporation Xi’an 710065China

The lifetime of Si-based environmental barrier coatings(EBCs)is constrained by thermally grown SiO_(2)oxidelayer(SiO_(2)-TGO),which can cause premature cracking and *** address this issue,a new approach for surfacemodification using aluminum is *** oxidation performance was examined in a 50 vol%H_(2)O-50 vol%O_(2)environment at 1350℃for up to 300 *** results indicate that a dense ytterbium aluminum garnet(YbAG)layer wasformed after modification,decreasing the porosity by 80%.Due to the elimination of fast diffusion channels and the lowoxygen permeability of YbAG,aluminum modification significantly reduced the growth rate of SiO_(2)-TGO by nearly twoorders of ***,its thickness decreased by more than 70%after 300 h of exposure.A diffusioncontrolled oxidation mechanism indicates that the modified dense surface is equivalent to an initial SiO_(2)layer with a specificthickness,causing a shift in the oxidation time and increasing the oxidation *** research provides valuableinsights for designing Si-based EBC with improved lifetimes.

关键词： environmental barrier coating(EBC) oxidation modification diffusion cracking