Photodynamic Therapy for Cancer Cells Using Metal-Halide Lamps

New metal-halide lamps were developed and their effect on the efficiency of photodynamic therapy (PDT) for cancer cells, murine thymic lymphoma cells (EL-4), was investigated. 5-Aminolevulinic acid-induced protoporphyrin IX was used as a photosensitizer. The metal-halide lamps were made by introducing sodium iodide (Na lamp), lithium iodide (Li lamp), and sodium iodide-lithium iodide mixture (Na-Li lamp) into their discharge tubes. These lamps emitted light in the range of 550 to 750 nm and had specific emission peaks at 580 and 600 nm for the Na lamp, 580, 610, and 680 nm for the Li lamp, and 580, 610, and 675 nm for the Na-Li lamp. Changes in the survival rate of EL-4 with increasing irradiation time indicated that PDT efficiency of the lamps increased in the order Li lamp < Na lamp < Na-Li lamp. We also found that a dark interval during irradiation of the light with the Na-Li lamp enhanced PDT efficiency.     

铷光谱灯光谱自吸收现象研究

由自吸收导致的铷光谱灯超精细光谱轮廓变形,对铷原子频标的频率稳定度有不利影响.用F-P干涉仪测量了三种常用铷光谱灯的超精细光谱轮廓,研究了启辉气体种类、压力、谱灯工作温度和激励功率对自吸收的影响.结果表明,充Ar和充Kr谱灯自吸收效应比较显著,充Xe谱灯自吸收不明显;适当增大气体压力、降低灯泡工作温度、增大射频激励功率,可以减小光谱灯的自吸收效应.     

Are transition-metal borides promising for Na ion batteries? A first-principles study on transition-metal boride monolayer

Although two-dimensional (2D) materials have been proposed as the promising candidates for Na ion batteries (NIBs), electrode materials with high specific capacity and moderate diffusion energy barriers are still scare. Here, we firstly demonstrated that transition-metal borides (TMB) are much more promising electrode materials than other transition metal compounds. Density functional theory (DFT) calculations are performed to investigate the electronic properties and Na storage capability of TMB monolayer, which is realized in recent experiments. TMB monolayer forms strong chemical interaction with Na atoms, and the diffusion energy barrier of Na atoms is much lower than LIBs. Importantly, TMB monolayer exhibits a very high Na storage capacity. Such exceptional properties, including high stoichiometry (namely TMBNa₂), excellent electronic conductivity, moderate Na diffusion and high operating voltage, endow TMB monolayers as very promising anode materials for NIBs.     

影响高功率脉冲氙灯寿命的因素

以美国NOVA和国家点火装置用的高功率脉冲氙灯为例,结合对神光Ⅲ装置用脉冲氙灯的分析,发现了影响脉冲氙灯失效的几个因素,包括石英灯管应力、氙灯尺寸、灯管微缺陷、电极溅射、灯头绝缘、氙气纯度、封接可靠性及周围氙灯放电。结果发现:在进灯能量相同的情况下,氙灯电极弧长越长,内径越大,寿命越高;石英灯管表面的静态拉应力、内表面的微缺陷以及周围氙灯的电离辐射使得氙灯的额外负载能量大大增加,这些是导致氙灯爆炸概率变大的直接因素。     

BaSi2O5：Pb荧光粉表面性能的改善

BaSi₂O₅:Pb(BSP)荧光粉现主要应用于晒黑灯,也常用于其他一些特殊用途的荧光灯,如捕蝇、光催化等。相比其他灯用荧光粉来说,这种荧光粉有一明显缺点,即光衰较大。目前解决这个问题的办法主要通过化学气相沉积法在BSP粉表面包覆Al₂O₃膜,提出了一种基于液相的表面处理方法,且在较高pH值下进行,该方法通过将荧光粉加入Ba²⁺离子溶液,使得溶液中Ba²⁺离子在粉表面富集,再经过滤、灼烧等后处理,得到处理后的BSP粉。以SEM,XPS等方法对其表面形貌和组分进行测试,并以未处理的BSP粉作对照进行发光性能测试,结果表明:阳离子溶液处理后荧光粉在发光性能上有了明显改善,光通维持率明显提高。     

真空罐内应用的太阳模拟灯阵热设计

为了解决太阳模拟灯阵整体放在真空罐内使用时的导热问题,采用热管导热的方案,设计了专门的氙灯导热机构。计算了液氮系统的导热能力,结果显示,真空罐液氮冷却系统的温度升高ΔT为2074 1 K,小于其过冷度4 K,表明真空罐液氮冷却系统完全可以将太阳模拟灯阵的热量导出。采用热管导热技术,设计了导热机构,用有限元分析法进行了热仿真分析,分析结果表明,氙灯阴阳极温度维持在100 ℃左右,氙灯灯泡维持在655 ℃左右,满足氙灯正常工作的温度条件;积分器和反射镜组件温度维持在200 ℃左右,椭球镜温度维持在135 ℃左右,亦满足正常工作的温度条件,从而验证了热设计的正确性。     

Pseudospark discharge in long time current pulse: electricalcharacterization and recovery phenomena

At high currents, the performance of triggered vacuum gaps is limited by the constriction of the arc discharge on the anode. In a symmetrical system within flat electrodes, a motionless anode spot appears in front of the trigger spark. A pseudo-spark system within electrode cavities and specific gas pressure provides a good mechanism for avoiding anode spot phenomena. It appears possible to obtain a high intensity diffuse discharge. In this paper, we present the experimental measurements of the instantaneous voltage and discharge current, (peak current less than 50 kA, discharge time between 20 and 300 μs). These measurements allow us to determine the dynamical resistance, mean voltage and energy lost during the conduction phase. Consequently, we refine our knowledge of discharge development. Additionally, we present a complementary investigation on quenching behavior     

Modeling of high pressure discharge lamps including electrodes

Electrode behavior in high pressure discharge lamps (HID), although understood qualitatively, is still not well understood quantitatively. Traditional models using different layers in front of the cathode are based on the assumption that the electrons gain substantial kinetic energy in the cathode fall to ionize the gas. For many HID lamps (e.g., p>1 MPa) this assumption may not be fulfilled. This paper uses a different model first proposed by Fischer (1987). We present modeling results for a Xe lamp with special emphasis on the cathode region     

Acceleration of re-ignition of high pressure mercury discharge lamps using photo-pre-ionization

High Intensity Discharge (HID) lamps are difficult to re-ignite rapidly because of the high pressure of metal vapor at high temperatures. We have succeeded in reducing the re-ignition time of high-pressure mercury lamps by using a pre-ionization step where an excess of electrons are generated by UV laser irradiation into the lamp. The effect of changing the laser focal point of the UV laser in the lamp and the position of an auxiliary electrode were also investigated. The time interval for re-ignition was reduced from 230s to 100s by laser irradiation near to the cathode. The results clearly showed that the effect of accelerating the re-ignition time by the pre-ionization step was determined by the behavior of excess electrons generated during the UV laser irradiation.     

Atomabsorption von Barium in Leuchtstofflampen

Evaporation of emitter material from electrodes of fluorescent lamps has been measured by means of atomic absorption of Ba. A hollow-cathode discharge lamp served as background radiator. The arrangement is briefly described. Spot resolved measurements has been done in preheating and in discharge regimes. Essential results are dependence on evaporation rate and filament structure, evaporation and arising of cathode spot in discharge, and diminished evaporation regarding preheating.     

铥原子激发能级超精细结构常数的测定

用铥空心阴极灯,采用光电流光谱技术测得铥原子21条一级跃迁谱线,确定了相应跃迁上能级的超精细结构常数,其中7个能级的参数为首次发表,运用同一空心阴极灯,采用双色双光子级联共振技术,由荧光法首次测得4个第二激发能级的超精细结构常数.     

碘化钠NaI(Tl)单晶闪烁探测器的应用

碘化钠NaI(Tl)单晶闪烁探测器由射线探测器、计算机多道、高压电源及线性放大器、计算机多道脉冲幅度分析器等部分组成。当放射源发出的γ射线进入闪烁体时,γ光子即与闪烁体中的原子、分子及晶体系统发生相互作用(如光电效应,康普顿散射和电子对效应等)。     

A new type of electrochemical cell based on the configuration NaI |PEG| I2

Different operating conditions of a new electrochemical cell based on sodium iodide and polyethylene glycol (PEG) polymer as separator as well as conducting electrolyte is reported. Five types of cells were fabricated using pure NaI, PC+NaI, water+NaI dil. HCl+NaI and dil. H₂SO₄+NaI in the cell configuration NaI |PEG| I₂ and NaI |PEG|s I₂+C. Their discharge characteristics were studied at room temperature (33 °C). From the cell parameters, it is found that the open circuit voltage ranges from 648 mV to 1023 mV and the short circuit current ranges from 29 μA to 4.8 mA.     

LED异形灯的散热设计与实验

为了提高LED灯具的散热能力,基于烟囱效应原理,设计了一种新型的LED灯具散热结构。该结构仅采用一块圆柱状基板,不需要散热器,突破了传统LED灯具的构造模式。运用软件Solidworks构建三维模型,用其插件Flow Simulation进行热仿真。当功率为10 W时,LED芯片最高温度为81.34℃。当功率增加到15 W时,最高温度变为105.54℃,高于芯片安全工作温度85℃。因此,本文提出在基板中间加入散热器的改进方案,使LED芯片最高温度下降了30.79℃。并以散热器翅片数12个、内环直径20 mm、翅片厚度1 mm为基础模型参数,进行优化试验。研究表明:在翅片数为12个、内环直径为12 mm、翅片厚度为1 mm时,LED异形灯的散热效果最好,此时,LED异形灯的最高温度为72.21℃。当功率为8,13,15,17,19 W时,LED异形灯芯片的温度都满足LED工作的安全要求。经过对8 W的LED异形灯样品的实验测试,测得其最高温度为53℃,与仿真结果仅相差1.01℃,证实了研究的准确性。所设计的LED异形灯,为解决大功率LED散热问题提供了一条新的途径。     

AA-stacked borophene-graphene bilayer as an anode material for alkali-metal ion batteries with a superhigh capacity

As the lightest two-dimensional material, monolayer borophene exhibits great potential as electrode materials, but it suffers from stability issues in the free-standing form. Here, the striped-borophene and graphene bilayer (sB/Gr) is found to be a high-performance anode material for rechargeable alkali-metal ion batteries. The first-principles results show that all the three alkali-metal atoms, Li, Na, and K, can be strongly adsorbed on sB/Gr with ultra-low diffusion barriers than that on pristine borophene/graphene, indicating good charge-discharge rates. Remarkably, high storage capacities are proposed for LIBs (1880 mA·h/g), NIBs (1648 mA·h/g), and KIBs (470 mA·h/g) with relatively small lattice change rate (<2.9%) in the process of alkali-metal atoms intercalations. These intriguing features of sB/Gr make it an excellent choice for batteries.     

镝灯研制及其在照相制版中的应用

本文介绍镝灯的基本工作原理、结构和特性。镝灯是一种稀土金属卤化物灯,是利用在碘化镝、碘化钬的蒸汽中放电发光而制成。它的发光效率在70流明/瓦以上,色温为6000K左右,目前使用寿命可达200小时以上。已在照相制版中试验应用。与碳精灯相比较,镝灯具有亮度高、体积小、电弧稳定、清洁等优点,是改进照相制版的一种新型光源。     

The conductivity and dielectric studies of solid polymer electrolytes based on poly (acrylamide-co-acrylic acid) doped with sodium iodide

Solid polymer electrolyte thin films based on polyacrylamide-co-acrylic acid (PAAC) doped with sodium iodide (NaI) with different ratios of polymer and salt added with fixed amount of additive of propylene carbonate (PC) were prepared by using solution casting method. The PC was added to the mixture of the solution to provide more flexibility to the polymer film by increasing the plasticity of the thin film membrane. The conductivity and dielectric studies were carried out on these thin films to understand the ion transport properties of the polymer electrolytes. The highest conductivity obtained was 1.88?×?10^?5 S cm^?1 for the 30% NaI salt-doped polymer electrolyte system at room temperature. The temperature-dependent conductivity agrees with Arrhenius relationship which shows that hopping mechanism of ions in the polymer matrix. The dielectric properties especially the loss tangent used to analyze the segmental relaxation of the polymer chain as more concentration of salt was incorporated. The electric modulus was studied to understand the electrical relaxation processes to overcome electrode polarization effect.     

Field emission pressure sensors with non-silicon membranes

We report on the fabrication of cold cathode emitter and the design parameter simulation of a functional field emission-based pressure sensor. This device comprises a membrane made of metallic compound acting as the anode in front of a flat cold cathode emitter. First, the mechanical deflection of a diaphragm under selected input pressures is modeled. The current density distribution in the deflected diaphragm is then calculated using realistic field emission characteristics from fabricated sulfur doped boron nitride (S-BN) cold cathode device. The total current output was found by integrating the measured current density of the fabricated electron emitter device over the entire diaphragm area of the membrane as function of external pressure. The results show that conventional silicon membranes would pose problems when implemented in a real field emission device, and show how the use of unconventional materials (i.e., TiN) can help overcome these problems.     

Characteristics of O(I) and N(I) resonance line broadening in low pressure helium discharge lamps

O(I) (130 nm) and N(I) (120 nm) resonance line broadening in a variety of rf- and microwave- excited low-pressure helium discharge lamps of the type used in laboratory and atmospheric experiments has been characterized by a line-absorption-titration technique. A line-absorption model with variable emission line width is used to fit experimentally observed absorptions of ground state O and N produced in a discharge-flow apparatus where the concentrations of the absorbing atoms are indepedently determined by chemical titration. The observed broadening is in general non-thermal and the effect is more pronounced for the O(I) lamps, for which the degree of line broadening increases with decreasing lamp pressure and discharge power. The O(I) results are interpreted in terms of an excitation mechanism which includes electron-impact excitation of O and dissociative excitation of O₂ by helium metastables.     

A Review of Anode Phenomena in Vacuum Arcs

This paper discusses are modes at the anode, experimental results pertinent to anode phenomena, and theoretical explanations of anode phenomena. A vacuum are can exhibit five anode discharge modes: (1) a low current mode in which the anode is basically passive, acting only as a collector of particles emitted from the cathode; (2) a second low current mode that can occur if the electrode material is readily sputtered (a flux of sputtered atoms will be emitted by the anode); (3) a footpoint mode, characterized by the appearance of one or more small luminous spots on the anode (footpoints are generally much cooler than the true anode spots present in the last two modes); (4) an anode spot mode in which one large or several small anode spots are present (such spots are very luminous, have a temperature near the atmospheric boiling point of the anode material, and are a copious source of vapor and ions); and (5) an intense are mode where an anode spot is present, but accompanied by severe cathode erosion. The are voltage is relatively low and quiet in the two low current modes and the intense are mode. It is usually high and noisy in the footpoint mode, and it can be either in the anode spot mode. Anode erosion is low, indeed negative, in the two low current modes, and it is low to moderate in the footpoint mode. Severe anode erosion occurs in both the anode spot and intense are modes. The dominant mechanism controlling the formation of an anode spot appears to depend upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum are being considered. In specific experimental conditions, either magnetic constriction in the gap plasma, or gross anode melting, or local anode evaporation can trigger the transition. However, the most probable explanation of anode spot formation is a combination theory, which considers magnetic constriction in the plasma together with the fluxes of material from the anode and cathode as well as the thermal, electrical, and geometric effects of the anode in analyzing the behavior of the anode and the nearby plasma.