O2分子吸附的金属表面的O2(1Δg)猝灭

建立了一套流动装置测量单重态氧O₂(¹Δ_g)在O₂分子吸附的金属Cu、Cr、Ni和Ag表面的猝灭几率. 随实验时间和O₂(¹Δ_g)浓度增加,猝灭几率增加. 当上述金属样品在几帕斯卡的真空度下暴露数小时后猝灭几率会回到原先水平. 提出了一种基于表面吸附位上弱化学吸附的表面吸附氧分子O₂(¹∑_{g相似文献}   

丰中子核125Sb的高自旋态

利用在束γ谱学方法,通过¹²⁴Sn(⁷Li,α2n)反应首次研究了丰中子核¹²⁵Sb的高自旋态.建立了自旋达23/2⁺、激发能至2637keV的能级纲图,其中包括21条新γ跃迁和14个新能级.在1970,2110和2471keV识别出了3个同质异能态,估计了它们的寿命范围,并建议分别具有πg_7/2ν(h_11/2s_1/2),πg_7/2ν(h_11/2d_3/2),πg_7/2ν(h²_11/2)三准粒子组态.根据价质子与¹²⁴Sn核芯激发态的耦合讨论了¹²⁵Sb的能级结构.     

2+1维U(1)格点胶球质量的变分计算

本文对具有严格基态解和正确经典连续极限的格点规范哈密顿量,采用变分法,计算了2+1维U(1)规范群0^+－和0⁺⁺胶子态的质量,在深度弱耦合区,得到am(0^+－)随1/g²增大而指数减少,而am(0⁺⁺)=2.78g².     

弹性共振散射反应的厚靶实验设计

为了开展次级束引起的弹性共振散射反应的厚靶实验, 在北京HI-13串列加速器的次级放射性核束装置上建立了一套包含飞行时间和大面积双面硅微条探测器的探测系统, 并用57.0MeV ¹⁷F次级束轰击7.66mg/cm²的(CH₂)_n靶对¹⁷F+p弹性共振散射反应进行了试测量.     

弱形变双奇核158Tm中的旋称反转

通过融合蒸发反应¹⁴⁴Nd(¹⁹F,5n)布居了双奇核¹⁵⁸Tm的高自旋态. 扩展了原来已知的带结构, 并建立了一条新转动带. 通过与相邻核的比较, 讨论¹⁵⁸Tm核中两条四准粒子带的内禀组态, 并分别指定为πh_11/2\otimes νh_9/2(α=+1/2)\otimes (νi_13/2)²和πh_11/2\otimes νh_9/2(α=－1/2)\otimes (νi_13/2)² 组态. 建立在πh_11/2\otimes νi_13/2组态上的转动带被观测到呈现持续旋称反转现象, 而前述的两条高自旋区的 四准粒子转动带也呈旋称反转. 对这两种类型的旋称反转现象的可能机制进行了简单而定性的讨论.     

脉冲软X光辐射三种材料的喷射冲量实验研究

 在强光一号脉冲加速器上进行了国内首次的实验室软X光辐射三种材料的喷射冲量研究。结果表明，在能量为(0.2～0.33)keV、平均脉宽为39ns左右的X光辐射下，对灰漆、白漆和硬铝，在能注量分别为(92～152)J/cm²、(115～136)J/cm²和(163～192)J/cm²时，它们的冲量耦合系数分别为(0.61～0.80)Pa·s/(J·cm^-2)、(0.58～0.97)Pa·s/(J·cm^-2)和(0.61～0.84)Pa·s/(J·cm^-2)。     

2+1维SU(3)群格点规范的胶球质量

本文对具有严格基态解的Hamiltonian,采用采用变分法,计算了2+1维SU(3)规范群的C=+1.C=－1胶球质量.得到在0<1/g²≤6范围内,标度行为是am₊=36.1g²、am_－=5.98g².     

Ag-Cu纳米颗粒修饰的N掺杂TiO2纳米棒阵列及其高效光催化CO2还原应用

本文采用微纳加工方法制备了负载高密度Ag-Cu纳米颗粒的N掺杂TiO₂纳米棒阵列样品. 通过TiO₂的N掺杂,可将其吸光范围调控至与Ag纳米颗粒的等离激元吸收频率相匹配的波段,从而实现复合材料中肖特基结与共振能量转移过程的协同作用. 与此同时,Cu纳米颗粒可以为CO₂还原提供活性位点. 在全谱光照射下,复合样品光催化CO₂还原的活性显著提高,CH₄生成速率可达720 μmol·g^-1·h^-1.     

125Ba高自旋态的测量

通过¹⁰⁹Ag(¹⁹F,3n)核反应布局了¹²⁵Ba核的激发态.使用带BGO康普顿抑制的高纯锗探测器阵列和常规在束γ实验技术,测量了它的高自旋态.建立在h_11/2中子支壳上的负宇称带和建立在g_7/2中子支壳上的正宇称带分别被延伸到了35/2^－和23/2⁺态.负宇称带显示出明显的正负Signature劈裂,而正宇称带则几乎没有这种劈裂.负宇称正负Signature带均出现反弯,其反弯处转动频率与¹²⁴Ba晕带反弯频率相近.正宇称带出开始出现反弯迹象.     

中等银纬区逆康普顿γ射线强度

使用最近期的EGRET/CGRO γ射线数据,确定出了中等银纬区(|b|=10°-20°)银河宇宙线与星际气体相互作用产生的γ射线的发射率q/4π,其中采用了由γ射线数据本身来确定该发射率的方法;并由此获得了以银经为函数的不同能区的逆康普顿(IC)γ射线积分强度.在该银纬区,沿银经平均的IC微分强度可表为:I_Ic(E)=1.58×10^－6E^{－2.08±0.06}cm^－2·s^－1·sr^－1GeV^－1,b=10°—20°;I_Ic(E)=2.08×10^－6E^{－2.03±0.06}cm^－2·s^－1·sr^－1GeV^－1,b=－20°—－10°,其中,能量E的范围为30MeV到4000MeV.     

Self-organization of five species in a cyclic competition game

Cyclic competition game models, particularly the “rock–paper–scissors” model, play important roles in exploring the problem of multi-species coexistence in spatially ecological systems. We propose an extended “rock–paper–scissors” game to model cyclic interactions among five species, and find that two of the five can coexistent when biodiversity disappears, which is different from the “rock–paper–scissors” game. As the number of fingers is five, we named the new model the “fingers” game, where the thumb, forefinger, middle finger, ring finger, and little finger cyclically dominate their subsequent species and are dominated by their former species. We investigate the “fingers” model in two ways: direct simulations and nonlinear partial differential equations. An important finding is that the number of species in a cyclic competition game has an influence on the emergence of biodiversity. To be specific, the “rock–paper–scissors” model is in favor of maintaining biodiversity in comparison with the “fingers” model when the variables (population size, reproduction rate, selection rate, and migration rate) are the same. It is also shown that the mobility and reproduction rate can promote or jeopardize biodiversity.     

Contrastive analysis on tone between Putonghua and Taiwan Mandarin

The differences of the pitch and duration of Chinese syllables between Putonghua （PTH） and Taiwan Mandarin （TM） were studied. The speech materials to be used are not only isolated syllables, but also sentences. The results reveal that： For the isolated syllables, T1 and T2 in TM are influenced by Minnan dialect, therefore their pitch are lower than those in PTH. T3 is fall-rise in PTH, while it is fall in TM. Moreover, the syllable duration sequence for different tone is T3〉T2〉T1〉T4 in PTH, while it is T1〉T2〉T3〉T4 in TM. For the syllables in sentences, T2 is mid-rise in PTH, while it is mid-level in TM. And the T3 is longer than T4 but shorter than T1 or T2 in PTH, while it is the shortest in TM. Furthermore the effects of prosodic phrase boundary on duration for different tones are almost the same in PTH, but the lengthening part of T1 or T2 is longer than that of T3 or T4 in TM.     

Experimental study on downstep in Chinese intonation

Downstep in pitch contour of Chinese Putonghua is examined using subtly designed sentences by controlling tone combinations. The results show both automatic and nonautomatic downstep phenomena exist in Chinese. In non-automatic downstep, low tones compress downwards the pitch range of the following syllables. and the main influence of downstep is on topline. Low tone not only lower the topline behind it, but also raise the high tones before it, the effects are compatible with each other. In automatic downstep, the topline of pitch contour in intonational phrase is presented as a linear downtrend, but it differs among speakers due to the effect of personal stress practice. In comparison with downstep phenomenon in other tone or non-tone languages, the downstep ratio in Chinese is not constant, and the domain of downstep is not limited within the adjacent tones.     

Abelian-Higgs phase of SU(2) QCD and glueball energy

It is shown that SU(2) QCD admits an dual Abelian-Higgs phase, with a Higgs vacuum of a type-Ⅱ superconductor. This is done by using a connection decomposition for the gluon field and the random-direction approximation. Using a bag picture with soft wall, we presented a calculational procedure for the glueball energy based on the recent proof for wall-vortices [Nucl. Phys. B 741(2006)1].     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Signal generation in an isotropic medium in scanning electron acoustic microscope

Based on the research in Ref. [5][Materials Science and Engineering, 1989; A122： 57 63], an improved model of heat source is set up, the different modes of Lamb wave in an isotropic sample generated by a chopped electron beam at frequency f are obtained with integral transform and normal function expansion method, and the output signal of PZT coupled at the back surface of the sample is found out. The generation mechanism of SEAM （Scanning Electron Acoustic Microscopy） signal is discussed. It shows that the SEAM is a near field imaging technique with high spatial resolution and its best lateral spatial resolution is about 2√2α （α is the radius of the focused electron beam）. Some of experimental results of SEAM images are presented in the paper and it shows that the spatial resolution of SEAM is better than 0.5 μm and smaller than the thermal diffusion length of the sample. Therefore the character of near field imaging in SEAM is also proved experimentally.     

High efficiency filtering using two-dimensional photonic crystal coupled cavity structures

Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies.