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利用SHML模型计算了密度为ρ=1g·cm-3、温度为150eV、200eV、250eV、300eV、400eV的Sn等离子体的随光子能量变化的辐射不透明度及Rosseland平均不透明度.分析了不透明度随光子能量变化曲线的吸收峰值(不透明度峰值)与能级跃迁的对应关系.还将Sn的Rosseland平均不透明度与DCA/UTA及STA模型计算结果作了比较,吻合较好.     

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利用分裂的屏蔽氢不透明度模型计算了Ar、Kr、Xe惰性元素混合物随光子能量变化的不透明度以及Rosseland平均不透明度。研究了温度为100～250eV,密度为0.5～2g·cm-3范围内惰性元素混合物的Rosseland平均不透明度与混合物质、混合比例、温度和密度的密切关系。结果显示,Ar-Xe混合以及Xe-Kr混合后的Rosseland平均不透明度比它们为纯元素时有较大的增加;而Ar-Kr混合后的Rosseland平均不透明度则比纯Kr低。通过对比纯惰性元素随光子能量变化的不透明度峰、谷值,分析了造成混合后不透明度增加或降低的原因,同时给出了获得惰性元素混合物平均不透明度为最大时的混合比例。     

DTA模型计算高温氟化钠等离子体的辐射不透明度

使用细致谱项模型(detailed term accounting,DTA)计算了局域热动平衡(local thermodynamic equilibrium,LTE)近似下氟化钠等离子体密度为0.01?g/cm3的等密度系列的谱分辨不透明度以及Rosseland和Planck平均不透明度,分析了钠和氟离子L→M跃迁对不透明度的贡献以及温度的升高对于两种元素的L→M跃迁吸收峰的影响.     

DTA模型计算高温氟化钠等离子体的辐射不透明度

使用细致谱项模型(detailed term accounting，DTA)计算了局域热动平衡(local thermodynamic equilibrium，LTE)近似下氟化钠等离子体密度为0．01g／cm^3的等密度系列的谱分辨不透明度以及Rosseland和Planck平均不透明度，分析了钠和氟离子L→M跃迁对不透明度的贡献以及温度的升高对于两种元素的L→M跃迁吸收峰的影响。     

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利用l能级分裂的屏蔽氢模型(SHML)，计算了不同混合比例的Au-Gd混合物在温度为250eV、密度为1g•cm–3的Rosseland平均不透明度。计算值与实验值和理论值吻合得较好。     

利用混合介质降低黑腔壁辐射能耗的理论研究

 采用Au-Gd混合介质作腔壁，增大腔壁Rosseland不透明度，降低其辐射能耗是提高黑腔辐射温度的途径之一。利用纯Au和Au-Gd混合介质的Rosseland平均辐射不透明度数据库和多次电离区物态方程加入一维辐射流体力学程序，计算分析了在神光 Ⅱ激光装置产生的黑腔X光辐射能源条件下， Au-Gd混合介质作腔壁对提高黑腔辐射温度的影响，得到了Au-Gd混合介质作腔壁可使黑腔辐射温度提高0.1~0.2MK的结论。     

高温稠密金等离子体辐射不透明度的多极效应

使用平均原子模型研究了电四极及更高阶跃迁对高温稠密金等离子体辐射不透明度的贡献.计算并讨论了在不同温度密度条件下,电四极,电八极,电十六极跃迁对束缚-束缚跃迁的影响.计算了密度为96.405 g/cm3时,不同温度条件下,电四极,电八极跃迁对Rosseland平均不透明度的贡献.考虑了电四极、电八极跃迁后金等离子体不透明度的相对改变最大分别为4.67%和1.5%,并和其它文献的理论结果进行了比较.     

Ne、Ar、Kr、Xe等离子体Planck和Rosseland平均不透明度的近似计算

根据平均原子模型和类氢光吸收系数，近似地计算了Ne、Ar、Kr、Xe等惰性元素高温、高密度等离子体的Planck和Rosseland不透明度。在计算线谱吸收过程中，采用了唯象方法处理线谱演化成谱带时的加宽效应及谱带重叠效应。将不透明度数据拟合成温度和密度的幂函数形式，它能够用于辐射体的数值拟合。     

电子传导不透明度计算

基于含温有界相对论Dirac自洽场原子模型,采用电子-离子散射机制,在Born近似下,计算了部分离化等离子体物质的电子传导不透明度(Electron Conductive Opacity)。以铯(Cs)为例,同他人结果作了比较,给出钛(Ti)元素温度kT=10～10~3eV,密度ρ=0.1ρ_0～10ρ_0范围的电子传导不透明度K_C。     

平均原子模型中谱线位置偏移对辐射不透明度的影响

使用平均原子(average atom,AA)模型计算了局域热动平衡近似下的Fe,Br等离子体的辐射不透明度.对AA模型中跃迁系的跃迁能量引入了统计修正，修正后的谱线位置与细致谱项模型的结果更接近，但仍然存在差距，进一步减小这种差距需要考虑等离子体的价态分布.研究了AA模型中这种谱线位置移动对平均不透明度的影响，计算了Fe等离子体等温度系列的平均不透明度，发现这种修正对于平均不透明度的影响是比较明显的.     

Transverse-momentum spectra in Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV and the pseudorapidity dependence of high-p(T) suppression

We present spectra of charged hadrons from Au+Au and d+Au collisions at sqrt[s(NN)]=200 GeV measured with the BRAHMS experiment at RHIC. The spectra for different collision centralities are compared to spectra from p+(-)p collisions at the same energy scaled by the number of binary collisions. The resulting ratios (nuclear modification factors) for central Au+Au collisions at eta=0 and eta=2.2 evidence a strong suppression in the high p(T) region (>2 GeV/c). In contrast, the d+Au nuclear modification factor (at eta=0) exhibits an enhancement of the high p(T) yields. These measurements indicate a high energy loss of the high p(T) particles in the medium created in the central Au+Au collisions. The lack of suppression in d+Au collisions makes it unlikely that initial state effects can explain the suppression in the central Au+Au collisions.     

Common suppression pattern of eta and pi0 mesons at high transverse momentum in Au + Au collisions at square root S(NN) = 200 GeV

Inclusive transverse momentum spectra of eta mesons have been measured within p(T) = 2-10 GeV/c at midrapidity by the PHENIX experiment in Au + Au collisions at square root S(NN) = 200 GeV. In central Au+Au the eta yields are significantly suppressed compared to peripheral Au + Au, d + Au, and p + p yields scaled by the corresponding number of nucleon-nucleon collisions. The magnitude, centrality, and p(T) dependence of the suppression is common, within errors, for eta and pi0. The ratio of eta to pi0 spectra at high p(T) amounts to 0.40 < R(eta/pi)0 < 0.48 for the three systems, in agreement with the world average measured in hadronic and nuclear reactions and, at large scaled momentum, in e+e- collisions.     

Plasmonic enhancement of the vanadium dioxide phase transition induced by low-power laser irradiation

Nanocomposites consisting of gold nanoparticle (NP) arrays and vanadium dioxide (VO₂) thin films are noteworthy for the tunability of both their thermal and optical properties. The localized surface plasmon resonance (LSPR) of the Au can be tuned when its dielectric environment is modulated by the semiconducting-to-metal phase transition (SMT) of the VO₂; the LSPR itself can be altered by changing the shape of the NPs and the pitch of the NP array. In principle, then it should be possible to choose a combination of VO₂ film and Au LSPR properties that maximizes the overall optical response of the nanocomposite. To demonstrate this effect, transient transmission measurements were conducted on lithographically fabricated arrays of Au NPs of diameter 140?nm, array spacing 350 nm, and covered with a 60?nm thick films of VO₂ via pulsed laser deposition. Both Au::VO₂ nanocomposites and bare VO₂ film were irradiated with a shuttered 785?nm pump laser, and their optical response was probed at 1550?nm by a fixed-frequency diode laser. The Au::VO₂ nanocomposite exhibited an increased effective absorption coefficient 1.5 times that of the plain film and required 37?% less laser power to induce the SMT. The time-dependent temperature rise in the film as a function of laser intensity was calculated from these measurements and compared with both analytic and finite-element models. Our results suggest that Au::VO₂ nanocomposites may be useful in applications such as thermal-management coatings for energy efficient ??smart?? windows.     

g factor measurements of high spin isomeric states in 187,189,191 Au

The g factors of three high spin isomers in ^187,189,191Au have been measured, using the time differential perturbed angular distributions. The reactions used and the results obtained for the g factors and the lifetimes are: ¹⁷²Yb(¹⁹F, 4nγ) ¹⁸⁷Au, g (31/2- or 35/2-) = 0.25 (3), T_1/2 = 102 (5) ns; ¹⁸¹Ta ( ¹²C, 4nγ) ¹⁸⁹Au, g (31/2+) = 0.42 (2), T_1/2 = 242 (10) ns; and ¹⁷⁶Yb(¹⁹F, 4nγ) ¹⁹¹Au, g (31/2+) = 0.42 (3) T^1/2 = 402 (20) ns. These results show that the structure of these isomers is consistent with a 1 proton, 2 neutrons structure. The experimental set-up was cheked by measuring the g factor of the Coulomb excited 197 keV, T_1/2 = 89.3 ns level of the ¹⁹F beam stopped in the lead backing.     

Structures,stabilities,and magnetic properties of the Fe_nAu(n=1-12) clusters

The configurations,stabilities,electronic,and magnetic properties of Fe_nAu(n = 1–12) clusters are investigated systematically by using the relativistic all-electron density functional theory with the generalized gradient approximation.The substitutional effects of Au in Fe_(n+1)(n = 1,2,4,5,10–12) clusters are found in optimized structures which keep the similar frameworks with the most stable Fe_(n+1)clusters.And the growth way for Fe_nAu(n = 6–9) clusters is that the Au atom occupies a peripheral position of Fen cluster.The peaks appear respectively at n = 6 and 9 for Fen Au clusters and at n = 5 and 10 for Fe_(n+1)clusters based on the size dependence of second-order difference of energy,implying that these clusters possess relatively high stabilities.The analysis of atomic net charge Q indicates that the charge always transfers from Fe to Au atom which causes the Au atom to be nearly non-magnetic,and the doped Au atom has little effect on the average magnetic moment of Fe atoms in Fen Au cluster.Finally,the total magnetic moment is reduced by 3 μB for each of Fen Au clusters except n = 3,11,and 12 compared with for corresponding pure Fe_(n+1) clusters.     

Identified baryon and meson distributions at large transverse momenta from Au + Au collisions at square root sNN=200 GeV

Transverse momentum spectra of pi+/-, p, and p up to 12 GeV/c at midrapidity in centrality selected Au + Au collisions at square root sNN=200 GeV are presented. In central Au + Au collisions, both pi +/- and p(p) show significant suppression with respect to binary scaling at pT approximately >4 GeV/c. Protons and antiprotons are less suppressed than pi+/-, in the range 1.5 approximately < pT approximately < 6 GeV/c. The pi-/pi+ and p/p ratios show at most a weak pT dependence and no significant centrality dependence. The p/pi ratios in central Au + Au collisions approach the values in p + p and d + Au collisions at pT approximately >5 GeV/c. The results at high pT indicate that the partonic sources of pi+/-, p, and p have similar energy loss when traversing the nuclear medium.     

Linear optical absorption and photoluminescence emission properties of gold nanoparticles prepared by laser ablation technique

Gold nanoparticles of average size varying between 1.1 and 3.3?nm are prepared by 1064?nm Nd:YAG laser ablation of solid gold target kept in ethylene glycol medium. The measured UV-Visible absorption spectra showed the presence of sharp absorption peaks in the UV and in the visible regions due to the interband transition and surface plasmon resonance (SPR) oscillations in Au nanoparticles, respectively. The increase in linewidth of the SPR peaks with the reduction in particle sizes is observed due to intrinsic size effects. The prepared samples exhibit photoluminescence (PL) emissions in the UV-Visible region peaked at ??354?nm due to the recombination of electrons with holes from sp conduction band to d-band of Au. The peak PL intensity in the sample prepared with 60 minutes of laser ablation time is enhanced by a factor of ??2.5 compared to that obtained in the sample prepared with a laser-ablation time duration of 15 minutes.     

Multilayer interference mirrors for the XUV range around 100 eV photon energy

For the first time successful results have been obtained demonstrating interference effects in the reflectance of multilayer films at high photon energies where n = 1 and k is large. Films with 3.5 to 4.5 periods of Au/C and Cu/C were investigated for angles of incidence α = 15° to α = 60° in the wavelength interval 80 to 300A?. The highest near-normal incidence reflectance found was R = 2.7% for Au/C and R = 1.2% for Cu/C at λ ～ 190A?and α = 15°. These values were by a factor of 7 higher than those for a single layered opaque Au film (respectively a factor of 6 for Cu) evaporated under the same conditions. Further improvements appear to be possible. Calculations were performed to guide the investigations and to help the interpretation of the results.     

Effect of Au interlayer thickness on the structural,electrical, and optical properties of GZO/Au/GZO multilayers

We report on the structural, electrical, and optical properties of Ga-doped ZnO/Au/Ga-doped ZnO (GZO/Au/GZO) multilayers as a function of Au interlayer thickness. Aggregated Au islands formed a continuous film as the thickness of the Au interlayer increased from 3 to 12 nm. Consequently, the sheet resistance, resistivity, and optical transmittance decreased with increasing Au interlayer thickness compared to a GZO single layer. However, a relatively high peak transmittance and a high figure of merit were obtained for an Au interlayer thickness of 9 nm. These results showed that the characteristics of GZO/Au/GZO multilayers could be improved by inserting an Au interlayer of optimized thickness. In addition, it indicated that the GZO/Au/GZO multilayer is the most promising candidates for indium free transparent conducting oxides (TCOs).     

Optical-pyrometric diagnostics of the state of silicon during nanopulsed laser irradiation

The dynamics of the reflectivity at ?? = 0.53 ??m and the IR radiation of silicon in the wavelength range 0.9?C1.2 ??m is studied under the action of nanosecond ruby laser radiation pulses. When radiation energy density W is lower than the threshold of laser-induced melting of the surface of a semiconductor crystal, the major contribution to the IR radiation emitted by this crystal is made by edge photoluminescence. As the melting threshold is exceeded, the nanosecond dynamics of the detected IR radiation changes from photoluminescence to the thermal radiation of the forming Si phase melt with a high reflectivity. The results of pyrometric measurements of the peak melt surface temperature as a function of W obtained at an effective wavelength ?? _e = 1.04 ??m of the detected IR radiation agree with the data of analogous measurements performed at ?? _e = 0.53 and 0.86 ??m.