期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
在短日照条件下温度和光合光子流量影响菊花新梢发育和花芽分化
1
作者 王磊 《北方园艺》 CAS 北大核心 1997年第5期52-54,共3页
光合光子流量(PPF),日温(DT)和夜温(NT)的影响决定了在短日照(SD)条件下生长的菊花(DendranthemagrandifloraTzvelv.灿烂的金色的安妮)叶片数目、叶片伸展率、新梢长度。如在一系列... 光合光子流量(PPF),日温(DT)和夜温(NT)的影响决定了在短日照(SD)条件下生长的菊花(DendranthemagrandifloraTzvelv.灿烂的金色的安妮)叶片数目、叶片伸展率、新梢长度。如在一系列指定条件下,花芽形态将出现在100天短日照之内,一个用于预测的函数关系首先被建立。从10℃~30℃范围内的日温(DT)和夜温(NT)所有组合被预测在高于10.8克分子/天米2光合光子流量(PPF)时导致花芽显露。当日温(DT)和夜温(NT)从10℃增加到30℃时,在花以下形成的叶片成二次方增加。当PPF从1.8t增加到21.6克分子/天米2时,每个枝条上只形成1~2片或更少的叶片。随着日平均温度的提高,叶片展开率从10°F0.2叶/天直线地增加到在30°F0.5叶/天。节间长度与昼夜温差(DIF=DT-NT)高度地相关,即DIF从-12°增加到12°渐渐地导致较长的节间。 展开更多
关键词 菊花 新梢发育 花芽分化 温度 光合光子流量
下载PDF
植物生长与光照的关系 被引量:44
2
作者 高鸿磊 诸定昌 《灯与照明》 2005年第4期1-4,共4页
由于人眼视觉函数和植物敏感曲线的不同,原有的适用于人眼的光度学方法将不适于植物。该文主要介绍两种全新的适用于植物的测量方法———促进光合作用辐射功率法和光合作用光子流量法,最后介绍一种使用促进光合作用的辐射功率法来对简... 由于人眼视觉函数和植物敏感曲线的不同,原有的适用于人眼的光度学方法将不适于植物。该文主要介绍两种全新的适用于植物的测量方法———促进光合作用辐射功率法和光合作用光子流量法,最后介绍一种使用促进光合作用的辐射功率法来对简单的植物照明方案进行设计的一般步骤。 展开更多
关键词 人眼视觉函数 植物敏感曲线 促进光合作用辐射功率 光合作用光子流量 植物生长灯
下载PDF
人眼光度学与植物光度学的单位转换 被引量:12
3
作者 高鸿磊 诸定昌 《灯与照明》 2007年第2期34-36,共3页
由于人眼视觉函数和植物敏感曲线的不同,原有的适用于人眼的光度学方法将不适于植物。该文在介绍人眼光度学、促进光合作用辐射功率和光合作用光子流量的基础上,主要从原理上推导出三个单位之间的转换关系,最后用三种光源具体举例计算。
关键词 人眼光度学 植物光度学 促进光合作用辐射功率 光合作用光子流量 单位的转换
下载PDF
近红外导航恒星排序方法研究
4
作者 魏伟 张辉 《现代导航》 2017年第2期83-86,共4页
天文导航具有自主性强、精度高和误差不随时间积累等优点,惯性导航系统常采用天文观测的方法来提高定位和定姿精度,全天时星跟踪器技术成为近年来国内研究的热点。近红外系统多基于2MASS星表产生导航星表,系统工作中需要对可观测恒星进... 天文导航具有自主性强、精度高和误差不随时间积累等优点,惯性导航系统常采用天文观测的方法来提高定位和定姿精度,全天时星跟踪器技术成为近年来国内研究的热点。近红外系统多基于2MASS星表产生导航星表,系统工作中需要对可观测恒星进行排序,实现对恒星的最优选择。本文阐述了2MASS近红外恒星的测星能力计算方法,利用给出的信噪比(Signal noise ratio:SNR)计算公式,对一组亮背景条件下的恒星SNR进行了计算,并据此进行了理论排序。利用外场观星试验拍摄的星图,计算了恒星星点的SNR,并按照实测星点SNR对恒星进行了排序。计算结果表明:导航恒星的理论SNR与实测SNR的排序结果完全一致。 展开更多
关键词 近红外恒星 导航星 光子流量密度 排序方法
下载PDF
脉冲星导航地面试验系统X射线模拟源测试分析
5
作者 刘思伟 王丽亚 +2 位作者 李毅恒 史钰锋 胡慧君 《测绘科学与工程》 2019年第3期1-6,共6页
X射线模拟源是脉冲星导航地面试验系统的关键器件,用于模拟脉冲星辐射离散X射线光子信号,其性能直接影响X射线探测器和脉冲星导航的性能评估。脉冲星导航地面试验系统的X射线模拟源由脉冲X射线模拟源和单色X射线模拟源组成。通过对两类... X射线模拟源是脉冲星导航地面试验系统的关键器件,用于模拟脉冲星辐射离散X射线光子信号,其性能直接影响X射线探测器和脉冲星导航的性能评估。脉冲星导航地面试验系统的X射线模拟源由脉冲X射线模拟源和单色X射线模拟源组成。通过对两类模拟源的辐射性能进行测试及分析,发现脉冲X射线模拟源覆盖了脉冲星导航使用的1-15keV软X射线能段,最大光子流量为21ph/s/cm2,流量稳定度为98.3%,恢复出脉冲轮廓的相似度达99.85%。单色X射线模拟源在软X射线频段能提供6种特征能谱,其能量分辨率分别为87.6eV@1.487keV、155.1eV@4.51keV、172.0eV@1.487keV、178.3eV@1.487keV、194.1eV@1.487keV、192.3eV@1.487keV。单色X射线模拟源在5.4keV处辐射最强,光子流量为48.48ph/s/cm2。测试结果表明,X射线模拟源辐射流量稳定,能量分辨率优于200eV,能满足X射线探测器性能测试的需求。 展开更多
关键词 X射线探测器 能量分辨率 脉冲星导航 光子流量 X射线模拟源
下载PDF
Numerical Study of Optimization of Layer Thickness in Bilayer Organic Light-Emitting Diodes 被引量:3
6
作者 彭应全 张磊 张旭 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第5期454-460,共7页
A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and c... A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed. 展开更多
关键词 organic light-emitting diodes BILAYER OPTIMIZATION
下载PDF
A comparison among optical emission spectroscopic methods of determining electron temperature in low pressure argon plasmas 被引量:3
7
作者 牛田野 曹金祥 +4 位作者 刘磊 刘金英 王艳 王亮 吕铀 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第9期2757-2763,共7页
In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas o... In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas of dc glow discharges at low pressures in laboratory by measuring the relative intensities of ArI lines at various pressures. These methods are developed respectively on the basis of the Fermi-Dirac model, corona model, and two kinds of electron collision cross section models according to the kinetic analysis. Their theoretical bases and the conditions to which they are applicable are reviewed, and their calculation results and fitting errors are compared with each other. The investigation has indicated that the electron temperatures obtained by the four methods become consistent with each other when the pressure increases in the low pressure argon plasmas. 展开更多
关键词 plasma diagnostics gas discharge optic emission spectroscopy electron temperature
下载PDF
快中子堆n,γ混合场中γ光子注量的测量研究 被引量:3
8
作者 雷家荣 袁永刚 +2 位作者 赵林 赵敏智 崔高显 《物理学报》 SCIE EI CAS CSCD 北大核心 2003年第1期53-57,共5页
用热释光探测器对快堆堆外n ,γ混合场进行了区分测量 ,结果表明 :该方法可有效的检测出n ,γ混合场的γ成分 ;为了更较精确地测量快堆n ,γ混合场γ光子注量 ,提出了采用新配方的热释光探测器LiFTLD(6 LiF ,7LiF各占5 0 % )与6 LiFTLD... 用热释光探测器对快堆堆外n ,γ混合场进行了区分测量 ,结果表明 :该方法可有效的检测出n ,γ混合场的γ成分 ;为了更较精确地测量快堆n ,γ混合场γ光子注量 ,提出了采用新配方的热释光探测器LiFTLD(6 LiF ,7LiF各占5 0 % )与6 LiFTLD成对使用的方法 .考虑到LiFTLD对中子吸收剂量的响应存在LET效应 ,对LiF(Mg ,Cu ,P)TLD进行了中子响应的LET效应因子RLET的实验测定 (RLET≈ 0 0 5 ) ,在此基础上 ,对6 LiF 7LiFTLD的成对使用测量快中子堆的n ,γ混合场中光子注量的方法进行了实验研究 .实验结果表明 ,混合场中的中子在7LiF(Mg ,Cu ,P)中产生的热释光量 (TL)占n ,γ产生的总TL的 8 1%— 17 1% .实验结果表明该方法是行之有效的 .为钝化中子谱的不确定性所致的影响 ,进一步提高γ光子注量测量结果的精度 ,提出了采用新配方的LiFTLD(6 LiF ,7LiF各占 5 0 % )与6 LiFTLD成对使用测量快堆n ,γ混合场γ光子注量的方法 . 展开更多
关键词 快中子堆 测量 n γ混合场 吸收剂量 LiFTLD LET 热释光探测器 γ光子流量
原文传递
Measurement of Neutron Fluxes and Spectra during the NT-TBM Operation of CN HCSB
9
作者 YANG Jinwei FENG Kaiming CHEN Zhi 《Southwestern Institute of Physics Annual Report》 2004年第1期97-100,共4页
Neutronics measurement system provides neutron fluxes and spectra at the locations of beryllium multiplier and tritium breeder during the operation of the NT-TBM (D-D and D-T phase in ITER). This is important for st... Neutronics measurement system provides neutron fluxes and spectra at the locations of beryllium multiplier and tritium breeder during the operation of the NT-TBM (D-D and D-T phase in ITER). This is important for studying and assessing capabilities of beryllium multiplier and tritium breeder in the China helium cooled solid breeder (CNHCSB). A special neutron diagnostic system has been proposed that allows to measure neutron fluxes and spectra without interrupt the operation of ITER. This system includes encapsulated foil activation analysis, micro-fission chamber detectors (MFC), and a compact neutron spectrometer using natural diamond detector (NDD). 展开更多
关键词 NT-TBM MFC NDD
下载PDF
Exceptionally efficient deep blue anthracene-based luminogens:design,synthesis,photophysical,and electroluminescent mechanisms 被引量:1
10
作者 Runda Guo Wei Liu +8 位作者 Shian Ying Yuwei Xu Yating Wen Yaxiong Wang Dehua Hu Xianfeng Qiao Bing Yang Dongge Ma Lei Wang 《Science Bulletin》 SCIE EI CSCD 2021年第20期2090-2098,M0004,共10页
Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent ... Achieving high-efficiency deep blue emitter with CIE_(y)<0.06(CIE,Commission Internationale de L’Eclairage)and external quantum efficiency(EQE)>10%has been a long-standing challenge for traditional fluorescent materials in organic light-emitting diodes(OLEDs).Here,we report the rational design and synthesis of two new deep blue luminogens:4-(10-(4’-(9 H-carbazol-9-yl)-2,5-dimethyl-[1,1’-biphe nyl]-4-yl)anthracen-9-yl)benzonitrile(2 M-ph-pCzAnBzt)and 4-(10-(4-(9 H-carbazol-9-yl)-2,5-dimethyl phenyl)anthracen-9-yl)benzonitrile(2 M-pCzAnBzt).In particular,2 M-ph-pCzAnBzt produces saturated deep blue emissions in a non-doped electroluminescent device with an exceptionally high EQE of 10.44% and CIE_(x,y)(0.151,0.057).The unprecedented electroluminescent efficiency is attributed to the combined effects of higher-order reversed intersystem crossing and triplet-triplet up-conversion,which are supported by analysis of theoretical calculation,triplet sensitization experiments,as well as nanosecond transient absorption spectroscopy.This research offers a new approach to resolve the shortage of high efficiency deep blue fluorescent emitters. 展开更多
关键词 Anthracene derivative Deep blue luminogen Hot excitons Triplet-triplet annihilation up-conversion Non-doped device
原文传递
Polyfluorenes containing pyrazine units:Synthesis,photophysics and electroluminescence 被引量:4
11
作者 WANG Ming,LI Ying,XIE ZhiYuan & WANG LiXiang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China 《Science China Chemistry》 SCIE EI CAS 2011年第4期656-665,共10页
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfe... A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-on voltages of their single-layer electroluminescent (EL) devices (ITO/PEDOT/polymer/LiF/Al) were at 6.1-4.0 V,which were much lower than that of PFO (7.0 V).The maximum brightness,current efficiency,and external quantum efficiency of all PFBY copolymers were higher than those of the PFO homopolymer.The single-layer device of PFBY5 was the best one in the copolymers,with a maximum brightness of 485 cd/m2,a current efficiency of 0.29 cd/A,and an external quantum efficiency of 0.10%.The introduction of PVK and TPBI for the multilayer device of PFBY5 increased the device efficiencies,which showed a maximum brightness of 3012 cd/m2,a maximum current efficiency of 1.81 cd/A,and an external quantum efficiency of 0.66%. 展开更多
关键词 PYRAZINE POLYFLUORENES energy transfer PLED
原文传递
Experimental platform for the investigation of magnetized-reverse-shock dynamics in the context of POLAR
12
作者 B. Albertazzi E. Falize +24 位作者 A. Pelka E Brack E Kroll R. Yurchak E. Brambrink E Mabey N. Ozaki S. Pikuz L. Van Box Som J. M. Bonnet-Bidaud J. E. Cross E. Filippov G. Gregori R. Kodama M. Mouchet T. Morita Y. Sakawa R. E Drake C. C. Kuranz M. J.-E. Manuel C. Li E Tzeferacos D. Lamb U. Schramm M. Koenig 《High Power Laser Science and Engineering》 SCIE CAS CSCD 2018年第3期36-49,共14页
The influence of a strong external magnetic field on the collimation of a high Mach number plasma flow and its collision with a solid obstacle is investigated experimentally and numerically. The laser irradiation (I ... The influence of a strong external magnetic field on the collimation of a high Mach number plasma flow and its collision with a solid obstacle is investigated experimentally and numerically. The laser irradiation (I - 2 × 10^14 W. cm-2) of a multilayer target generates a shock wave that produces a rear side plasma expanding flow. Immersed in a homogeneous 10 T external magnetic field, this plasma flow propagates in vacuum and impacts an obstacle located a few mm from the main target. A reverse shock is then formed with typical velocities of the order of 15-20 4- 5 km/s. The experimental results are compared with 2D radiative magnetohydrodynamic simulations using the FLASH code. This platform allows investigating the dynamics of reverse shock, mimicking the processes occurring in a cataclysmic variable of polar type. 展开更多
关键词 accretion processes high-power laser HYDRODYNAMICS laboratory astrophysics POLAR radiative shocks
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部