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Constant light in early life induces fear-related behavior in chickens with suppressed melatonin secretion and disrupted hippocampal expression of clock-and BDNF-associated genes 被引量:1
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作者 Yang Yang Wei Cong +5 位作者 Jie Liu Mindie Zhao Peirong Xu Wanwan Han Deyun Wang Ruqian Zhao 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2022年第6期1799-1809,共11页
Background: Light management plays an important role in the growth and behavior of broiler chickens. Constant light in early post hatch stage has been a common practice in broiler industry for improving growth perform... Background: Light management plays an important role in the growth and behavior of broiler chickens. Constant light in early post hatch stage has been a common practice in broiler industry for improving growth performance,while whether and how constant light in early life affects the behavior of broiler chickens is rarely reported.Results: In this study, newly hatched chicks were kept in either constant(24 L:0 D, LL) or(12 L:12 D, LD) photoperiod for 7 d and then maintained in 12 L:12 D thereafter until 21 days of age. Constant light increased the average daily feed intake but not the body weight, which led to higher feed conversion ratio. Chickens in LL group exhibited fear-related behaviors, which was associated with higher corticosterone, lower melatonin and 5-HT levels. Concurrently, constant light exposure increased the mRNA expression of clock-related genes and suppressed the expression of antioxidative genes in the hippocampus. Moreover, brain derived neurotrophic factor/extracel ular signal-regulated kinase(BDNF/ERK) pathway was suppressed in the hippocampus of chickens exposed to constant light in the first week post hatching.Conclusions: These findings indicate that constant light exposure in early life suppress melatonin secretion and disrupts hippocampal expression of genes involved in circadian clock and BDNF/ERK pathway, thereby contributing to fear-related behaviors in the chicken. 展开更多
关键词 BDNF/ERK constant light Fear-related behavior Hippocampus
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Simultaneous estimation of aerosol optical constants and size distribution from angular light-scattering measurement signals 被引量:4
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作者 Zhen-Zong He Dong Liang +1 位作者 Jun-Kui Mao Xing-Si Han 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第5期564-572,共9页
The angular light-scattering measurement(ALSM) method combined with an improved artificial bee colony algorithm is introduced to determine aerosol optical constants and aerosol size distribution(ASD) simultaneousl... The angular light-scattering measurement(ALSM) method combined with an improved artificial bee colony algorithm is introduced to determine aerosol optical constants and aerosol size distribution(ASD) simultaneously. Meanwhile, an optimized selection principle of the ALSM signals based on the sensitivity analysis and principle component analysis(PCA)is proposed to improve the accuracy of the retrieval results. The sensitivity analysis of the ALSM signals to the optical constants or characteristic parameters in the ASD is studied first to find the optimized selection region of measurement angles. Then, the PCA is adopted to select the optimized measurement angles within the optimized selection region obtained by sensitivity analysis. The investigation reveals that, compared with random selection measurement angles, the optimized selection measurement angles can provide more useful measurement information to ensure the retrieval accuracy. Finally,the aerosol optical constants and the ASDs are reconstructed simultaneously. The results show that the retrieval accuracy of refractive indices is better than that of absorption indices, while the characteristic parameters in ASDs have similar retrieval accuracy. Moreover, the retrieval accuracy in studying L-N distribution is a little better than that in studying Gamma distribution for the difference of corresponding correlation coefficient matrixes of the ALSM signals. All the results confirm that the proposed technique is an effective and reliable technique in estimating the aerosol optical constants and ASD simultaneously. 展开更多
关键词 angular light-scattering measurement method aerosol optical constants aerosol size distribution inverse radiation problem
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A Relationship between Dispersion Measure and Redshift Derived in Terms of New Tired Light 被引量:6
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作者 Lyndon Ashmore 《Journal of High Energy Physics, Gravitation and Cosmology》 2016年第4期512-530,共20页
New data from FRB’s have provided an exciting new window on the cosmos. For the first time we have both Dispersion Measure (DM) from distant sources and their red-shift. This gives us the opportunity to determine the... New data from FRB’s have provided an exciting new window on the cosmos. For the first time we have both Dispersion Measure (DM) from distant sources and their red-shift. This gives us the opportunity to determine the average electron number density in intergalactic space and thus test New Tired Light predictions. Here, in an alternative cosmology, the universe is static and redshifts are produced by an interaction between photons and the electrons in the intergalactic medium. In a paper published in summer 2006 New Tired Light (NTL) predicted an average electron number density of n = 0.5 m<sup>-3</sup>. In 2016 a paper was published reporting that for the first time the DM of a FRB and the redshift of the host galaxy had been found. Using standard physics this confirmed the electron number density as n = 0.5 m<sup>-3</sup>. The prediction NTL made ten years earlier was proved to be correct. Using this measured electron number density enabled a definitive value of the Hubble constant to be made by New Tired Light and the value is 63 km/s per Mpc which compares well with currently accepted values. Importantly, since in NTL the redshift and dispersion are both due to the electrons in IG space, a relationship between DM’s and redshift can be predicted. NTL predicts that DM and LN(1 + z) will be directly proportional and related by the formula DM = mec/2hr<sub>e</sub>(3.086 × 1022) where me, re are the rest mass and classical radius of the electron, c is the speed of light in a vacuum and h is the plank constant. The numerical term is to change units from pccm<sup>-3</sup> to m<sup>-2</sup>. This reduces to DM = 2380LN(1 + z). Using data from five FRB’s this is tested and a linear relation is seen of the form DM = 1830LN(1 + z). The gradient of the plot from the observed data is within 23% of that predicted by NTL. Recently the Tolman Surface Brightness test has been applied to the HUDF and the results support a static universe whilst the possibility of two differing types of SN Ia whose distribution changes with distances means that tired light models can no longer be ruled out. Using SDF we know the distance to the Atlia galaxy cluster as 1.26 × 10<sup>24</sup> m. With the average electron number density of n = 0.5 m<sup>-3</sup> found from the Dispersion Measures of the FRB’s, from first principles, New Tired Light gives a calculated predicted redshift of 0.0086. This compares well with the value found spectroscopically of 0.0087—a difference of approximately 1%. It is shown that if the energy transferred to a recoiling electron when a UV photon of wavelength λ = 5 × 10<sup>-8</sup> m interacts with it is emitted as a secondary photon that photon will have a wavelength of 2.2 mm— the wavelength at which the CMB curve peaks. 展开更多
关键词 REDSHIFT Tired light Hubble constant Expanding Universe CMB Supernovae Time Dilation
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Fundamental Physical Constants and Primary Physical Parameters
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作者 Vladimir S. Netchitailo 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2023年第1期190-209,共20页
Every four years the Committee on Data for Science and Technology (CODATA) supplies a self-consistent set of values of the basic constants and conversion factors of physics recommended for international use. In 2013, ... Every four years the Committee on Data for Science and Technology (CODATA) supplies a self-consistent set of values of the basic constants and conversion factors of physics recommended for international use. In 2013, the World-Universe Model (WUM) proposed a principally different depiction of the World as an alternative to the picture of the Big Bang Model. This article: 1) Gives the short history of Classical Physics before Special Relativity;2) Calculates Fundamental Physical Constants based on experimentally measured Rydberg constant, Electrodynamic constant, Electron Charge-to-Mass Ratio, and Planck constant;3) Discusses Electrodynamic constant and Speed of Light;4) Considers Dimensionless Fundamental Parameters (Dirac Large Number Q and Dimensionless Rydberg Constant α);5) Calculates Newtonian Constant of Gravitation based on the Inter-connectivity of Primary Physical Parameters;6) Makes a detailed analysis of the Self-consistency of Fundamental Physical Constants and Primary Physical Parameters through the prism of WUM. The performed analysis suggests: 1) Discontinuing using the notion “Vacuum” and its characteristics (Speed of Light in Vacuum, Characteristic Impedance of Vacuum, Vacuum Magnetic Permeability, Vacuum Electric Permittivity);2) Accepting the exact numerical values of Electrodynamic constant, Planck constant, Elementary charge, and Dimensionless Rydberg Constant α. WUM recommends the predicted value of Newtonian Constant of Gravitation in 2018 to be considered in CODATA Recommend Values of the Fundamental Physical Constants 2022. 展开更多
关键词 Classical Physics Fundamental Physical constants Electrodynamic constant Speed of light Dirac Large Number Dimensionless Rydberg constant Newtonian constant of Gravitation Self-Consistency of Fundamental Physical constants
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On the Possibility of Variable Speed of Light in Vacuum 被引量:1
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作者 Qinghua Cui 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2022年第4期927-934,共8页
We previously revealed a quantitative relation by which the fine-structure constant α can be described by the temperature T of cosmic microwave background (CMB) with several other fundamental constants, including the... We previously revealed a quantitative relation by which the fine-structure constant α can be described by the temperature T of cosmic microwave background (CMB) with several other fundamental constants, including the elementary charge e, the Boltzmann constant k, the Planck constant h, and the light of speed in vacuum c. Given that the value of α is quite conserved but T is variable across CMBs, we propose that c changes with T and can be given by T, the present CMB temperature T<sub>0</sub> and the present light speed c<sub>0</sub>. As T is continuously decreasing, c is thus predicted to decrease at a rate of ~2.15 centimeters/second (cm/s) per year. Moreover, we provide a lot of evidence to support this finding. In conclusion, this study suggests a possibility of variable speed of light in vacuum. 展开更多
关键词 Speed of light in Vacuum Fine-Structure constant Cosmic Microwave Background Earth-Moon Distance
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Variable Physical Constants and Beyond
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作者 Qinghua Cui 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2023年第1期116-123,共8页
We previously revealed that the speed of light in vacuum c, the gravitational constant G, the vacuum permittivity ε, and the vacuum permeability μ can be defined by the temperature T (or the expected average frequen... We previously revealed that the speed of light in vacuum c, the gravitational constant G, the vacuum permittivity ε, and the vacuum permeability μ can be defined by the temperature T (or the expected average frequency f) of cosmic microwave background (CMB) radiation. Given that CMB is continuously cooling, that is, T is continuously decreasing, we proposed that the above “constants” are variable and their values at some space-time with CMB temperature T (c<sub>T</sub>, G<sub>T</sub>, ε<sub>T</sub>, and μ<sub>T</sub>) can be described using their values (c<sub>0</sub>, G<sub>0</sub>, ε<sub>0</sub>, and μ<sub>0</sub>) and the temperature (T<sub>0</sub>) of CMB at present space-time. Based on the above observation, a number of physical equations related with these constants are re-described in this study, including relativity equation, mass-energy equation, and Maxwell’s equations, etc. 展开更多
关键词 Speed of light in Vacuum Gravitational constant Vacuum Permittivity Vacuum Permeability Cosmic Microwave Background
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Z型异质结复合薄膜UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni的可见光催化性能及机理
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作者 赵娣 刘洪燕 +4 位作者 王树军 孙欣语 张紫璇 齐学宇 刘子帆 《材料导报》 北大核心 2025年第8期153-158,共6页
设计和合成高效光催化剂需要实现反应位点的精确调控、光诱导载流子的快速迁移以及可见光的有效吸收。本工作采用恒流电沉积法制备了UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni复合薄膜。UIO-66-NH_(2)和Ag_(3)PO_(4)的能带结构匹配良好,同时纳... 设计和合成高效光催化剂需要实现反应位点的精确调控、光诱导载流子的快速迁移以及可见光的有效吸收。本工作采用恒流电沉积法制备了UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni复合薄膜。UIO-66-NH_(2)和Ag_(3)PO_(4)的能带结构匹配良好,同时纳米Ag作为光生载流子分离中心,形成了由Ag_(3)PO_(4)、Ag和UIO-66-NH_(2)组成的Z型异质结光催化体系,有效地分离了光生电子-空穴对,保留了强氧化-还原活性位点,因而UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni复合薄膜在可见光下表现出优异的光催化性能。此外,光电化学测试结果表明,UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni复合薄膜具有更高的载流子分离速率和更低的催化还原溶解O_(2)的反应势垒。活性物种实验结果表明,·O_(2)^(-)和空穴(h^(+))在光催化降解中起主要作用,进一步证实了系统的Z型异质结光催化降解机制。 展开更多
关键词 UIO-66-NH_(2)/Ag/Ag_(3)PO_(4)/Ni复合薄膜 Z型异质结 恒流电沉积 可见光 光催化
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低介电耐高温含硅链段聚碳酸酯的合成与表征
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作者 黄小青 李伟浩 +2 位作者 舒绪刚 陈佳志 李岱远 《塑料工业》 北大核心 2025年第7期159-164,171,共7页
聚碳酸酯(PC)在5G、人工智能蓬勃发展的时代具有广阔应用前景,但通用PC材料无法满足耐高温、低介电常数等苛刻性能的要求。以三光气(BTC)、3,3′,5,5′-四甲基双酚A(TMBPA)、苯酚硅油(KF2201)等原料,通过调控TMBPA、KF2201的比例,采用... 聚碳酸酯(PC)在5G、人工智能蓬勃发展的时代具有广阔应用前景,但通用PC材料无法满足耐高温、低介电常数等苛刻性能的要求。以三光气(BTC)、3,3′,5,5′-四甲基双酚A(TMBPA)、苯酚硅油(KF2201)等原料,通过调控TMBPA、KF2201的比例,采用界面缩聚法合成了一系列四甲基双酚A-苯酚硅油型共聚PC(Si-PC),并通过溶剂挥发成膜。利用傅里叶红外光谱、核磁共振氢谱、差示扫描量热测试和介电性能测试等对聚合物膜的结构和性能进行了系统表征。结果表明,所制备的聚合物膜具有优异的综合性能,尤其是耐高温性能、介电性能和光学性能。当KF2201的质量分数为30%时,聚合物膜的玻璃化转变温度(T_(g))为163℃,热分解温度(T_(d5%))为432℃;在10 GHz条件下,其介电常数(ε)为2.530,介电损耗角正切(tanδ)为0.00798;在400~800 nm波段的透光率均超过81.7%,并保持较好的力学性能和流动性。这表明,TMBPA与KF2201的加入可以降低PC的介电常数及提升其耐高温性能,同时兼顾材料的力学性能、光学性能及流动性。 展开更多
关键词 苯酚硅油 3 3′ 5 5′-四甲基双酚A 玻璃化转变温度 介电常数 透光率
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持续光照对小鼠肝脏脂代谢和体质量的影响
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作者 朱奎成 杜春燕 何龙 《中国细胞生物学学报》 2025年第7期1636-1643,共8页
夜间暴露于人造光(ALAN)会扰乱生物节律,并与代谢综合征密切有关,但发生机制尚不清楚。将C57BL/6小鼠随机分为正常光照组、24 h持续光照组和非诺贝特干预组。称量小鼠体质量、肝脏湿重,计算肝脏指数;酶法测定甘油三酯(TG);ELISA法检测... 夜间暴露于人造光(ALAN)会扰乱生物节律,并与代谢综合征密切有关,但发生机制尚不清楚。将C57BL/6小鼠随机分为正常光照组、24 h持续光照组和非诺贝特干预组。称量小鼠体质量、肝脏湿重,计算肝脏指数;酶法测定甘油三酯(TG);ELISA法检测血清载脂蛋白B(ApoB)含量;HE染色观察肝脏和棕色脂肪组织(BAT)病理学变化;油红O染色分析肝细胞脂质蓄积;荧光定量PCR(RT-qPCR)检测下丘脑和肝脏与应激、生物钟和脂质代谢相关基因的mRNA水平。结果表明,与正常光照组相比,持续光照组小鼠的体质量、肝脏湿重、肝脏指数、血清ApoB、肝脏和血清TG含量均升高,肝细胞肿胀和脂质沉积,脂肪细胞体积增大。持续光照组小鼠下丘脑内质网应激基因Atf4表达水平升高,肝脏生物钟基因Rev-erbα表达水平降低,进而抑制参与肝脏脂肪酸氧化分解代谢相关基因(如Fgf21、Pgc1α、Pparα、Cpt1a和Aco等)表达。非诺贝特处理4周能显著抑制持续光照组小鼠体质量增长和肝脏脂质沉积,脂肪细胞变小,肝脏Pparα及脂解相关基因表达水平显著升高。由此提示,持续光照会扰乱生物钟导致肥胖,这机制可能与抑制肝脏脂肪酸氧化分解代谢基因相关。 展开更多
关键词 持续光照 肝脏 脂肪组织 脂质代谢 体质量 小鼠
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基于恒定电压法的光储充电最大功率跟踪
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作者 李自荣 范远 +2 位作者 唐诚 梁倩 朱学贵 《电工技术》 2025年第8期57-60,共4页
针对光储充电电路采用优化算法进行最大功率点跟踪时,存在实现困难、成本高等问题,设计了一种基于恒定电压法的光储充电最大功率跟踪电路。该光储充电电路由GaAs光伏电池、CN3791模块和锂离子电池构成,在对锂电池依次进行涓流充电、恒... 针对光储充电电路采用优化算法进行最大功率点跟踪时,存在实现困难、成本高等问题,设计了一种基于恒定电压法的光储充电最大功率跟踪电路。该光储充电电路由GaAs光伏电池、CN3791模块和锂离子电池构成,在对锂电池依次进行涓流充电、恒流充电和恒压充电时,均能使光伏电池在最大功率输出状态下完成,并由LED灯指示工作状态。实验结果表明,在不同辐照度下对锂离子电池充电时,光储充电电路的光伏电池均保持在最大功率点附近工作。所设计的光储充电电路能够快速跟踪最大功率点,为锂离子电池稳定充电,给便携式设备供电提供了低成本选择。 展开更多
关键词 光储充电 最大功率点跟踪 恒定电压法 CN3791
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HID航空照明技术的研究与应用
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作者 徐彤 《科技资讯》 2025年第11期93-95,共3页
对高强度气体放电(High Intensity Discharge,HID)照明技术在航空领域的应用进行了研究论述。明确了主要的研究内容,提出了需要解决的关键技术,并结合实际案例给出了软硬件设计、材料、工艺解决方案。旨在突破HID航空照明关键技术,掌握... 对高强度气体放电(High Intensity Discharge,HID)照明技术在航空领域的应用进行了研究论述。明确了主要的研究内容,提出了需要解决的关键技术,并结合实际案例给出了软硬件设计、材料、工艺解决方案。旨在突破HID航空照明关键技术,掌握具有自主知识产权的核心技术且达到国际先进水平,并在国内各类飞机着陆灯、滑行灯、转弯灯、观察灯上推广应用。 展开更多
关键词 HID照明技术 HID照明控制器 恒功率控制 高压驱动 状态监控 软件控制
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光照应激对SD大鼠睾丸促性腺激素释放激素受体表达的影响 被引量:6
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作者 时姗姗 马恒辉 +5 位作者 章如松 周航波 陶晓倩 柳海燕 林杈英 姚兵 《医学研究生学报》 CAS 2011年第2期122-126,共5页
目的多种应激方式均能抑制生殖功能,但其对调控机制仍缺少系统的研究。通过观察光照应激状态下SD大鼠睾丸内促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)受体蛋白和mRNA表达变化,为寻找应激状态下生殖系统调节机制提供依... 目的多种应激方式均能抑制生殖功能,但其对调控机制仍缺少系统的研究。通过观察光照应激状态下SD大鼠睾丸内促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)受体蛋白和mRNA表达变化,为寻找应激状态下生殖系统调节机制提供依据。方法建立SD大鼠光照应激模型,将70只大鼠随机分为14组,其中7组(实验组)24 h持续光照,包括短期光照应激(2、3、4和7d)和长期光照应激(14、21和28d),另7组按正常昼夜节律并作为对照组;分别取实验组和相应对照组的睾丸组织,采用Western blot和RT-PCR分析GnRH受体在各时间段大鼠睾丸组织中的蛋白和mRNA表达变化,并用化学发光法检测血清中睾酮的含量。结果 Western blot结果显示:与对照组比较,持续光照2、3、4和7 d后,实验组大鼠睾丸GnRH受体表达无明显变化;持续光照14d和21d后,实验组大鼠睾丸GnRH受体的表达分别升高了27.8%±11.2%和40.6%±24.8%,差异具有统计学意义(P<0.05);持续光照28 d后,实验组大鼠睾丸GnRH受体的表达升高了26.1%±33.6%,但差异无统计学意义(P>0.05)。RT-PCR结果显示:GnRH受体的mRNA表达和其蛋白表达呈现相同的趋势,但差异无统计学意义(P>0.05)。随着光照时间的延长,睾酮分泌量与对照组相比持续上升,差异有统计学意义(P<0.05)。结论 GnRHR随着光照应激时间的延长,在大鼠睾丸中蛋白表达量发生改变。提示在光照应激中,GnRH受体对生殖功能具有潜在的生理调节功能。 展开更多
关键词 光照 应激 睾丸 促性腺激素释放激素
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光照应激对SD大鼠小肠促性腺激素释放激素受体表达的影响 被引量:5
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作者 时姗姗 陶晓倩 +4 位作者 韩雪峰 卢坤刚 张艳梅 柳海燕 姚兵 《医学研究生学报》 CAS 2009年第11期1127-1130,1135,I0003,共6页
目的:机体遭受各种创伤应激后,常出现各种胃肠道症状,并且已有研究表明大鼠的消化系统广泛分布有促性腺激素释放激素(GnRH)受体免疫反应阳性细胞。文中观察光照应激状态下SD大鼠小肠黏膜GnRH受体的分布和表达变化。方法:建立SD大鼠光照... 目的:机体遭受各种创伤应激后,常出现各种胃肠道症状,并且已有研究表明大鼠的消化系统广泛分布有促性腺激素释放激素(GnRH)受体免疫反应阳性细胞。文中观察光照应激状态下SD大鼠小肠黏膜GnRH受体的分布和表达变化。方法:建立SD大鼠光照应激模型,24 h持续光照,分为短期光照应激(2、3、4、7 d)和长期光照应激(14、21、28 d),分别取应激组和相应对照组的小肠组织,采用免疫组化和Western blot技术分析GnRH受体在各时间段大鼠小肠组织中的分布和表达变化。结果:Western blot结果显示:与对照组相比,持续光照2、3、4、7 d后,实验组大鼠小肠GnRH受体表达无明显变化;持续光照14 d和21 d后,实验组大鼠小肠GnRH受体的相对表达量分别约升高了56.5%和59.9%,具有显著性差异(P<0.05);持续光照28 d后,实验组大鼠小肠GnRH受体的相对表达量约升高了27.8%,但无显著性差异(P>0.05)。免疫组织化学显示,GnRH受体在大鼠小肠中的分布未见明显改变,但长期应激后期实验组(14、21、28 d)GnRH受体免疫组化显色较深,说明GnRH受体表达升高,这与Western blot的结果基本一致。结论:GnRH受体随着光照应激时间的延长,在大鼠小肠中表达量发生改变。提示在光照应激中,GnRH对消化功能具有潜在的生理调节功能。 展开更多
关键词 光照 应激 小肠 促性腺激素释放激素
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频闪光源和交变光源对蝗虫趋光响应的试验 被引量:11
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作者 刘启航 周强 《江苏大学学报(自然科学版)》 EI CAS 北大核心 2011年第3期260-265,共6页
为给光场耦合调控性蝗虫诱导LED光源的研制提供技术支持,利用LED光源和行为试验装置采用对比试验法,进行了蝗虫趋光响应频闪光频率和交变光周期的优选以及蝗虫对频闪光、余弦交变光相对恒定光的增效差异,探讨了频闪光和余弦交变光对蝗... 为给光场耦合调控性蝗虫诱导LED光源的研制提供技术支持,利用LED光源和行为试验装置采用对比试验法,进行了蝗虫趋光响应频闪光频率和交变光周期的优选以及蝗虫对频闪光、余弦交变光相对恒定光的增效差异,探讨了频闪光和余弦交变光对蝗虫趋光增效的机理.结果显示:光谱色光照、发光频率及发光周期范围影响蝗虫的趋光响应,其中发光间隔为30 ms的频闪紫光对蝗虫的趋光增效优于其他频闪光,蝗虫对发光周期为640 ms的余弦交变紫光的趋光响应相对于频闪光、周期交变光、恒定光最优,且蝗虫对周期为640 ms的余弦交变绿紫蓝光的响应优于发光间隔为30 ms的频闪紫光;在蝗虫敏感光谱耐光光照阀值基础上,频闪光和余弦交变光的合理组合可提高蝗虫的趋光增效范围. 展开更多
关键词 蝗虫 频闪光 余弦交变光 恒定光照 趋光响应
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光衍射法测量低频液体表面波衰减系数 被引量:3
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作者 祁建霞 苗润才 董军 《激光技术》 CAS CSCD 北大核心 2008年第5期496-498,520,共4页
为了对低频液体表面波的衰减系数进行测量,利用液体表面波的光衍射方法,得到了稳定、清晰的衍射图样,并发现了衍射条纹强度分布与光斑入射点位置有关。对此进行了理论分析,得到了衍射条纹强度分布与液体表面波振幅之间的解析关系式以及... 为了对低频液体表面波的衰减系数进行测量,利用液体表面波的光衍射方法,得到了稳定、清晰的衍射图样,并发现了衍射条纹强度分布与光斑入射点位置有关。对此进行了理论分析,得到了衍射条纹强度分布与液体表面波振幅之间的解析关系式以及表面波振幅随距离变化的实验数据。结果表明,可以根据衍射条纹的强度分布来测量液体表面波的衰减系数,与经典流体力学理论相比较,符合较好。这一结果对测量液体的物理参量是有帮助的。 展开更多
关键词 测量与计量 衰减系数 光衍射 声表面波
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溶剂对壳聚糖粘度及Mark-Houwink方程参数的影响 被引量:3
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作者 倪红 杨艳燕 阎达中 《化学世界》 CAS CSCD 北大核心 2003年第8期416-418,415,共4页
采用粘度法分析了不同溶剂对壳聚糖粘度的影响 ,用光散射法测定了超声波分级的壳聚糖的相对分子质量。实验结果表明 :四种溶剂体系分别溶解壳聚糖 ,其粘度行为不同 ,溶剂的离子强度越大 ,壳聚糖的比浓粘度越小。在 0 .3mol/ L乙酸 + 0 .... 采用粘度法分析了不同溶剂对壳聚糖粘度的影响 ,用光散射法测定了超声波分级的壳聚糖的相对分子质量。实验结果表明 :四种溶剂体系分别溶解壳聚糖 ,其粘度行为不同 ,溶剂的离子强度越大 ,壳聚糖的比浓粘度越小。在 0 .3mol/ L乙酸 + 0 .3mol/ L乙酸钠溶剂的条件下 ,应用 Mark-Houwink方程测得 K=0 .1 81 cm3 / g、α=0 .62 ,说明离子强度越大 ,壳聚糖分子的聚集态越大 ,α越小。为了获得准确的 K、α值和壳聚糖的相对分子质量 ,必须选择合适的溶剂体系来消除这种聚集态的影响。 展开更多
关键词 壳聚糖 Mark-Houwink方程参数 光散射法 粘度 相对分子质量
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Fe-Mn-Ge合金γ→ε马氏体相变的研究 被引量:2
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作者 张斌 彭颖红 +2 位作者 陆兴 覃作祥 张彦生 《金属学报》 SCIE EI CAS CSCD 北大核心 2001年第12期1238-1242,共5页
利用金相组织观察、透射电子显微镜(TEM)分析和点阵参数测定方法研究了 Ge含量对 Fe-24Mn合金马氏体相变和显微组织结构的影响.结果表明,Fe-24Mn合金在冷却过程中产生大量的ε马氏体.在较低 Ge含量合金中的... 利用金相组织观察、透射电子显微镜(TEM)分析和点阵参数测定方法研究了 Ge含量对 Fe-24Mn合金马氏体相变和显微组织结构的影响.结果表明,Fe-24Mn合金在冷却过程中产生大量的ε马氏体.在较低 Ge含量合金中的后形成马氏体可以穿越或终止在另一取向的先形成马氏体片中.宽大的马氏体片是由大量相互平行的层错构成.随Ge含量的增加,马氏体片之间以交截或平行为主.这一结果表明:Ge的加入使Fe-24Mn合金中奥氏体层错能增加,合金中的ε马氏体数量减少.马氏体转变开始点 Ms降低 Ge增大 Fe-24Mn合金奥氏体的点阵常数,但对 展开更多
关键词 Fe-Mn-Ge合金 堆垛层错 点阵常数 形状记忆效应 马氏体相变 形状记忆合金
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光照应激对SD大鼠小肠中annexin 5表达的影响 被引量:1
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作者 时姗姗 卢坤刚 +3 位作者 柳海燕 陶晓倩 林钗英 姚兵 《临床检验杂志》 CAS CSCD 北大核心 2010年第3期221-223,共3页
目的观察光照应激状态下SD大鼠小肠黏膜组织中annexin 5的分布和表达变化。方法建立SD大鼠光照应激模型,24 h持续光照,分为短期光照应激(2、3、4、7 d)和长期光照应激(14、21、28 d),分别取应激组和相应对照组的大鼠小肠组织,采用免疫... 目的观察光照应激状态下SD大鼠小肠黏膜组织中annexin 5的分布和表达变化。方法建立SD大鼠光照应激模型,24 h持续光照,分为短期光照应激(2、3、4、7 d)和长期光照应激(14、21、28 d),分别取应激组和相应对照组的大鼠小肠组织,采用免疫组织化学和western blot技术分析annexin 5在各时间段大鼠小肠组织中的分布和表达。结果western blot结果显示,与对照组相比,持续光照2、3、4、7 d,实验组大鼠小肠中annexin 5表达无明显变化;持续光照14 d和21 d,实验组大鼠小肠中annexin 5的表达量显著高于对照大鼠,具有统计学意义(P<0.05);持续光照28 d,实验组大鼠小肠中annexin 5表达量虽仍高于对照鼠,但无显著性差异(P>0.05)。免疫组织化学显示,annexin 5在大鼠小肠中的分布未见明显改变,但光照应激后期实验组(14、21、28 d)annexin 5免疫组化显色较深。结论在光照应激后期(14、21 d)annexin 5的表达量明显增加。随着应激时间的延长(28 d),机体内代偿机制的建立,实验组annexin 5逐渐恢复至正常水平。说明大鼠小肠中annexin 5参与了应激过程。 展开更多
关键词 光照 应激 小肠 annexin5
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基于发光二极管的普朗克常量的测量 被引量:5
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作者 王瑗 潘葳 李向亭 《物理实验》 北大核心 2010年第10期5-7,共3页
采用电流表外接法测量发光二极管的伏安特性,确定正向阈值电压;使用多通道光谱仪测量LED的光谱特性,确定与阈值电压对应的LED辐射光的峰值波长,从而计算出普朗克常量.发蓝光、红光及绿光LED测量结果表明h的理论值处于测量值的置信区间内.
关键词 普朗克常量 发光二极管 伏安特性 光谱特性
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