对眼睛造成伤害的几种辐射光线

一、红外线对眼睛的伤害 红外线是一种热辐射的电磁波,其波长在760nm～400,000nm之间,自然界的红外线辐射源,主要是太阳光,红外线约占太阳光的60％。 根据红外线辐射所能产生的效应,可分为三类:①短波红外线,其波长在760nm～1400nm之间;②中波红外线,波长在1400nm～3000nm之间;③长波红外线,波长在3000nm～400000nm之间。

空间防辐射镜技术产业化

NASA为了开发在空间环境下保护人眼不受太阳强光刺激,以及空间辐射的眼睛保护技术,其喷气推进实验室的研究人员深入研究了鹰等鸟类的眼睛构造。研究发现,鹰眼含有一种油珠,可以防止强辐射光线（蓝光、紫光和紫外线光），并能透过视觉增强光线（红色、桔色和绿色）。这种油珠可以吸收短波光线，降低眩光而增加彩色对比度和清晰度，从而使鹰具有敏锐的视觉。因此，鹰可以在高空或者远距离分辨出猎物。据此，NASA喷气推进实验室的研究人员开发出含有微细氧化锌粒子的眼睛防护镜片。

Nonlinear Absorption and Low-threshold Two-photon Pumped Amplified Stimulated Emission from FAPbBr_(3) Nanocrystals

Formamidinium lead bromide(FAPbBr_(3))nanocrystals(NCs)have been considered to be a good optoelectronic material due to their pure green emission,excellent stability and superior carrier transport characteristics.However,two-photon pumped amplified spontaneous emission(ASE)and the corresponding nonlinear optical properties of FAPbBr_(3) NCs are scarcely revealed.Herein,we synthesized colloidal FAPbBr_(3) NCs with different sizes by changing the molar ratio of FABr/PbBr_(2) in the precursor solution,using ligand assisted precipitation(LARP)technology at room temperature.Photoluminescence(PL)and time resolved photoluminescence(TRPL)spectroscopy were measured to characterize their ASE properties.And their nonlinear optical properties were studied through the Zscan technique and the two-photon excited fluorescence method.The stimulated emission properties including oneand two-photon pumped ASE have been realized from FAPbBr_(3) NCs.With large two-photon absorption coefficient(0.27 cm/GW)and high non-linear absorption cross-section(7.52×10^(5) GM),ASE with threshold as low as 9.8μJ/cm^(2) and 487μJ/cm^(2) have been obtained from colloidal FAPbBr_(3) NCs using one-and two-photon excitations.These results indicate that as a new possible green-emitting frequency-upconversion material with low thresholds,FAPbBr_(3) NCs hold great potential in the development of high-performance two-photon pump lasers.

图书馆保护古籍善本的几点措施

负载着人类知识财富的古籍善本以其不可替代的文物价值和史料价值成为各大图书馆珍藏的珍本。如何将这些古籍永久保存下去,必须注意存放环境的科学性,本文从存放环境的温湿度等几个方面论述了其对古籍善本的影响及防护措施。

水基清洗剂残留物对金属防锈的影响

通过对表面含清洗剂残留物的金属制品在不同条件下腐蚀状态的试验，分析了自然光线辐射程度、残留量对金属腐蚀的影响及致使防锈性能下降的因素。

Cloud Point Extraction of Polycyclic Aromatic Hydrocarbons in Aqueous Solution with Silicone Surfactants

Cloud point extraction （CPE） processes with two silicone surfactants, Dow Coming DC-190 and DC-193, were studied as preconcentration and treatment for the water polluted by three trace polycyclic aromatic hydrocarbons （PAHs）： anthracene, phenanthrene and pyrene. For all cases, the volumes of surfactant-rich phase obtained by two silicone surfactants were very small, i.e. a lower water content in the surfactant-rich phase was obtained. For example, less than 3% of the initial solution was obtained in a 1% （by mass） surfactant solution, which was much smaller than that of TX-114 in the same surfactant concentration. And TX-114 is known as a high compact surfactant-rich phase among most nonionic surfactants, thus the comparison showed that an excellent enrichment was ensured in the analysis application by the CPE process with the silicone surfactants, and the lower water content obtained in the surfactant-rich phase is also important in the large scale water treatment. The influences of additives and phase separation methodology on the recovery of PAHs were discussed. Comparing with DC-193, DC-190 has a lower cloud point and a higher recovery （near 100%） of all the three PAHs in same surfactant concentration, which was required for application as a preconcentration process prior to HPLC system. However the DC-190 solution is hard to be phase separated only by heating, whereas DC-193 has a relative higher phase separating speed by heating, but a high cloud point （around 360K） limits its application. Due to the phase separation by heating is the only method of CPE suitable to the large scale water treatment, the mixtures of two silicone surfacrants solutions were investigated in this study. A solution containing 1% of mixed DC-190 and DC-193 （in the ratio of 90 ： 10） removed anthracene, phenanthrene and pyrene near 100% with a relative low cloud point and quick phase separating speed.

Reduction of Radiation Damage in Mice after Acute and Prolonged Irradiation with Gamma Rays by Means of Laser Device

An opportunity to use laser radiation as a means to reduce negative aftermath of acute and prolonged exposure to ionizing radiation was checked. The mice were exposed to γ- rays of ^60Co （whole body irradiation） in the dose of 7 Gy （the transitional clinical form of the acute radiation sickness）. The dose rate at acute irradiation was 1.14 Gy/min, and at prolonged exposure, 0.027 Gy/min. Laser radiation in the dose l mJ/cm^2 was used to irradiate only the back of a mouse. First, the mice were exposed to γ-radiation, then to laser radiation. The time interval between two types of irradiation did not exceed 30 min. It was shown that the radiation protection of mice with laser radiation is possible at exposure to ionizing radiation in a wide dose interval and can reduce negative after-effects of both the acute and prolonged radiation exposure.

Effect of γ-ray Radiation on the Loss of Optical Fiber in Visible Range

The mechanism of γ-ray radiation induced absorption loss of the optical fiber in visible range is analyzed. According to the mechanism, the quantitative relation between loss in optical fiber and γ-ray cumulation dose is found by use of methods of solid physics and statistic physics. This quantitative relation is certified in terms of the results of radiation experiment.

Effect of sample radius on stability of electromagnetic levitation melting

Based on the power dissipating model of spherical sample in free convection gas medium and the expression of input power, the model of temperature calculation for electromagnetic levitation melting sample was established. Considering the limitation of levitation force and levitation sample temperature,the principle of stability levitation zone computation was determined. A spherical sample （ThDy）Fe2 under the protection of argon gas was examined, and the effect of radius of levitation sample and perturbation on the stable levitation zone was investigated. The results show that longitudinal perturbation and transverse perturbation can shorten the length of stable levitation zone and the range of levitation sample radius. By increasing the sample radius and weakening the perturbation the electromagnetic levitation melting stability of sample can be improved.

IMPACT OF CLOUD DROPLETS SPECTRAL UNCERTAINTY ON MESOSCALE PRECIPITATION

1 INTRODUCTION Cloud radiation is one of the most important and indefinite factors in atmospheric radiation. As shown in a comparative study by Cess et al. with a climate model, differences can be very large in the outcome of varying schemes of cloud parameterization. It is therefore of great significance to have a relatively accurate scheme of cloud parameterization for the atmospheric radiative transfer process. According to the Mie＇s scattering theory, the scale parameter of the particulate has a very important effect on its optical property. It is then seen that the number concentration and size distribution of cloud droplets play an important in the determination of the optical properties of cloud droplets.

Facile Synthesis of Coronene Dimers Having Unique Optical Properties

The authors synthesized very pure dimer phase of coroneae by simple heat-treatment and subsequent sublimation purification. It was confirmed by laser desorption/ionization mass spectroscopy measurements that pure dimer phase of coronenes can be obtained by controlling the fusing and sublimation temperatures. The crystal structure of the dimer phase was analyzed by synchrotron XRD （X-ray diffraction） experiments. It was also found that very bright red light is emitted by irradiating ultra violet light （λ = 350 nm） to the dimer phase. The external and internal quantum yields were determined to be 5.56% and 6.95%, respectively.

Linear Polarization Components of Scattered 90°

A comparison is made of the intensity distribution of the horizontally and vertically polarized radiation sidescattered from small spherical particles in a cylindrical scattering volume.The incident radiation is a nearly collimated linearly polarized He-Ne laser beam.The scattering medium consists of various concentrations of particles which are either 0.22 μm or 0.494 μm in diameter and which were suspended in filtered,distilled water.In general,the effect of the diameter of the particle on depolari-zing the incident beam is more important than the particle concentration,detector depth,and so on.

Natural Radioactivity Measurements for Some Algerian Building Materials

The objective of this work is to assess the radiation hazards associated gamma rays from building materials. Natural gamma rays activities of natural radionuclide represented mainly by three natural radioactive series ^238U, ^235U and ^232Th, and the primordial ^40K in the samples of building materials which consist of bricks, ceramics, marble and gypsum from different areas of eastern Algeria are measured using gamma ray spectrometry. The values of the activities of these radionuclides do not clearly reflect the radiation hazard associated with these materials. Therefore, the radium equivalent （Raeq） concentration is defined taking into account the effectiveness of these isotopes in creating the radiation hazard. Radium equivalent activities, external and internal hazard indices （Hex and Hin） are calculated from the activities of ^226Ra, ^232Th and ^40K for suitability of the materials.

Effects of polypeptide from Chlamys farreri on amino acid con-tent in guinea pig skin irradiated by chronic ultraviolet A and B

We examined the effects of polypeptide from Chlamys farreri (PCF) on the amount of hy-droxyproline in guinea pig skin irradiated by chronic ultraviolet A (UVA) and ultraviolet B (UVB) radiation. PCF was applied locally before repeated exposure of guinea pig to UVA and UVB. The contents of hy-droxyproline and other amino acids in guinea pig skin were determined by automatic amino acid analyzer. Our results showed that: (1) long-time UVA and UVB radiation can reduce dramatically the amounts of hy-droxyproline, aspartic acid, threonine, glycine, phenylalanine and lysine in guinea pig skin in comparison with the control group (P < 0.05); (2) Compared with model group, pre-treatment with 5 % and 20 % PCF prior to UVA and UVB radiation can inhibit the decline of amino acids content in guinea pig skin in a dose-dependent manner (P < 0.05). As the decrease of hydroxyproline, glycine and lysine contents in the skin directly reflexes type I collagen degeneration, our results indicated that the chronic application of PCF can protect skin type I collagen against UV radiation, and thus protect skin from photoaging.

太阳系外的“死行星”

充满辐射，大气 PSR B1257＋12星系是人们最先发现的系外行星星系之一。据悉，该星系对于已知生物来说，就像是一个墓地。来自超新星的巨大冲击波，剥离了该星系的所有大气。行星被暴露在致命的宇宙辐射之下，致使该星系与生命无缘。就算曾经有生物一度生活在这个星系中，也已走向覆灭。现在，星球上只留下众多阴森恐怖的岩石，并不时地发出强辐射光线。

欧盟新一代高效太阳能电池转化效率已超28%

欧盟第七研发框架计划（FP7）提供300万欧元，总研发投入400万欧元，支持欧盟6个成员国及联系国意大利、西班牙、德国、英国、瑞典和瑞士的跨学科科技人员组成欧洲GLOBASOL科研团队。从2013年3月开始，长期致力于新一代高效太阳能电池技术的研制开发。GLOBASOL科研团队确定的技术开发路线是最大化吸收利用太阳辐射全光谱光线，不仅需要提高太阳光伏转化效率还需提高太阳辐射热转化效率。吸收材料是提高太阳全光谱光热能转化为电能效率的关键，科研团队采取“二步走”战略，研制基于有机或有机金属全染料以及准固态电介质的创新型敏化介观太阳能电池（SMSCs）材料。SMSCs可高效吸收750纳米波长以内的太阳能辐射光线，再通过纳米结晶技术，又称量子点技术，高效吸收750-1100纳米波长的太阳辐射光线。创新型的光子间隙结构设计放大了对太阳红外和近红外光谱的吸收，设计成太阳能电池串联安排的顶层单元，有助于吸收太阳辐射光线中大部分透明的低能光子。

Research into Excited Long Lived 0.6-6.0 keV Energy Levels in the Cathode Solid Medium of Glow Discharge by X-Ray Emission Registration

X-ray emission from metal cathodes in glow discharge （current is up to 300 mA, voltage is 1,500-4,300 V） experiments in the spectral range from 700 eV to 6 keV has been observed. The effect has been seen with a variety of different metal cathodes （including AI, Sc, Ti, V, Ni, Nb, Zr, Mo, Pd, Ta, W, and Pt）, as well as with different gasses （including D2, H2, Kr, Ar, and Xe） at low pressure （3-10 Torr）. We present results from a variety of diagnostics, including： pinhole camera imaging; thermo luminescent detector measurements; time-resolved scintillator measurements; and a curved mica spectrometer to register X-ray spectra. Both diffuse and collimated X-ray emission have been observed.. Diffuse emission occurs in bursts of X-rays; with up to 10^5 bursts per second, with up to 10^6 photons per burst during the discharge. Collimated X-ray emission appears in the form of beamlets directed normal to the cathodes surface with a very small angular divergence; with up to 104 bursts per second, and up to 1013 photons overall up to 20 h after discharge switch off. Based on these experimental results we propose a phenomenological model of processes.

The Effectiveness of Radiation Damage Reduction in Mice by Laser Light in Dependence of the Time Interval between Exposures

A research was carried out to determine the period of time during which it is possible to reduce the radiation damage in mice by means of laser radiation （650 nm） after gamma irradiation. First, the mice were exposed to γ- radiation （whole body irradiation）, then after 2 h or 24 h they were irradiated with laser radiation. The results of these studies have shown that the use of laser irradiation to reduce radiation damage in mice is effective 24 h after the exposure to 5 Gy ionizing radiation which leads to the bone-marrow clinical form of the ARS （Acute radiation sickness）. In case of the lethal dose of ionizing radiation 7 Gy （the transitional clinical form of the ARS）, the increase in life expectancy of mice is observed using laser radiation both 2 and 24 h after the exposure to γ- radiation, but the effectiveness of the laser used 2 h after the ionizing radiation is significantly more efficient.

Photoionization and Dissociation Study of 2-Methyl-2-propen-1-ol:Experimental and Theoretical Insights

The photoionization and dissociation of 2-methyl-2-propen-1-ol(MPO)have been investigated by using molecular beam experimental apparatus with tunable vacuum ultraviolet synchrotron radiation in the photon energy region of 8.0-15.5 eV.The photoionization efficiency(PIE)curves for molecule ion and fragment ions:C4H8O^+,C4H7O^+,C3H5O^+,C4H7^+,C4H6^+,C4H5^+,C2H4O^+,C2H3O+,C3H6^+,C3H5^+,C3H3^+,CH3O^+,CHO^+have been measured,and the ionization energy(IE)and the appearance energies(AEs)of the fragment ions have been obtained.The stable species and the first order saddle points have been calculated on the CCSD(T)/cc-pvTZ//B3LYP/6-31+G(d,p)level.With combination of theoretical and experimental results,the dissociative photoionization pathways of 2-methyl-2-propen-1-ol are proposed.Hydrogen migrations within the molecule are the dominant processes in most of the fragmentation pathways of MPO.

多模光纤中简并模式群的分别探测

用多模倾斜光纤光栅(Tilted fiber Bragg grating,TFBG)实现多模光纤中简并模式群(Degenerated modegroup,DMG)的分别探测。多模倾斜光纤光栅将光纤中的导模耦合到辐射光线,用透镜将辐射光线聚焦在焦平面上,使非简并模式群对应的辐射光线的像在焦平面上分离。在焦平面上用空间滤波器使简并模式群选择透过并进行分别探测。用芯径为62.5μm的标准通信多模光纤进行了简并模式群分别探测实验,用单模光纤激励多模光纤,测量简并模式群功率随激励光纤的横向对准偏差的变化关系。低阶简并模式群的测量结果与仿真计算结果基本一致,高阶简并模式群的测量结果与仿真结果有一些不同。用倾斜光纤光栅进行单简并模式群激励,在单简并模式群条件下测量简并模式群耦合效率的想法还需进一步实验验证。