野百合的组织培养研究

对采自大量子河森林公园的野百合进行鳞片诱导和快速繁殖组织培养研究.结果表明:鳞片下部可直接诱导生芽、生根,是初代培养的最佳外植体;6-BA浓度为0.5mg/L,NAA浓度分别为0.05mg/L,L和0.1mg/L有较高的芽诱导率;在NAA:6-BA=1:20的培养基中愈伤组织诱导结果较好;诱导鳞片生根的6-BA浓度不宜过高,0.5mg/L较适宜生根;鳞片凹面接触培养基仅有愈伤组织形成,凸面接触培养基可产生鳞芽;用低浓度(0.1mg/L～0.5mg/L)IAA诱导生根效果比NAA好;以1/2锯末+1/2洁净河沙为栽培基质的移栽苗长势最好.     

熔石英亚表面三维Hertz锥形划痕附近光强分布的数值模拟

熔石英亚表面划痕对入射激光的调制是导致光学材料损伤的主要因素.本文建立了熔石英后表面上三维Hertz锥形划痕模型,采用三维时域有限差分方法对划痕周围的电场强度进行了计算模拟,并分别讨论了划痕的深度、半径以及倾斜角度对入射光场调制作用的影响.结果表明：Hertz锥形划痕中心区域的电场增强效果最明显,最容易被辐照损伤;划痕的深度从λ变化到9.5λ的过程中,熔石英内的最大电场强度逐渐增大;半径小于15λ的Hertz锥形划痕较容易引起熔石英的损伤,当半径大于175λ时,熔石英内的最大电场强度都维持在2.5 V/m,不再受半径大小影响;当入射激光在划痕的内侧界面和熔石英后表面之间发生内全反射时,光场增强效果愈加明显. 关键词： 三维时域有限差分 Hertz锥形划痕 电场分布 数值模拟     

大型激光原型装置低燃料面密度诊断技术

由于某大型激光原型装置内爆实验的燃料面密度很低,提出了利用充纯D燃料内爆产生的初级DD中子和次级DT中子的产额比值来诊断燃料面密度的方法。在该原型装置的首轮内爆实验中,利用研制的高灵敏塑料闪烁体探测器对初级DD中子产额和次级DT中子产额进行了测量。通过实验发现,当初级DD中子产额高于108时,可以测得次级DT中子实验数据。建立了均匀内爆模型,用初级和次级中子产额比值法对燃料面密度进行计算,获得的该原型装置首轮内爆实验燃料压缩的平均面密度小于4.0 mg/cm2。     

Optical and structural properties of Ge-ion-implanted fused silica after annealing in different ambient conditions

Ge+ ions are implanted into fused silica glass at room temperature and a fluence of 1×10 17 cm-2 . The as-implanted samples are annealed in O2, N2 and Ar atmospheres separately. Ge0 , GeO and GeO2 coexist in the as-implanted and annealed samples. Annealing in different atmospheres at 600℃ leads each composite to change its content. After annealing at 1000℃, there remains some amount of Ge 0 in the substrates. However, the content of Ge decreases due to out-diffusion. After annealing in N2 , Si–N composite is formed. The absorption peak of GeO appears at 240 nm after annealing in O2 atmosphere, and a new absorption peak occurs at 418 nm after annealing in N2 atmosphere, which is attributed to the Si–N composite. There is no absorption peak appearing after annealing in Ar atmosphere. Transmission electron microscopic images confirm the formation of Ge nanoparticles in the as-implanted sample and GeO 2 nanoparticles in the annealed sample. In the present study, the GeO content and the GeO2 content depend on annealing temperature and atmosphere. Three photoluminescence emission band peaks at 290, 385 and 415 nm appear after ion implantation and they become strong with the increase of annealing temperature below 700℃, and their photoluminescences recover to the values of as-grown samples after annealing at 700℃. Optical absorption and photoluminescence depend on the annealing temperature and atmosphere.     

Structural,electronic and magnetic properties of the Mn-Ni(110) c(2×2) surface alloy

<正>Using first-principles total energy method,we study the structural,the electronic and the magnetic properties of the MnNi(110) c(2×2) surface alloy.Paramagnetic,ferromagnetic,and antiferromagnetic surfaces in the top layer and the second layer are considered.It turns out that the substitutional alloy in the outermost layer with ferromagnetic surface is the most stable in all cases.The buckling of the Mn-Ni(110) c(2×2) surface alloy in the top layer is as large as 0.26 A(1 A=0.1 nm) and the weak rippling is 0.038 A in the third layer,in excellent agreement with experimental results.It is proved that the magnetism of Mn can stabilize this surface alloy.Electronic structures show a large magnetic splitting for the Mn atom,which is slightly higher than that of Mn-Ni(100) c(2×2) surface alloy(3.41 eV) due to the higher magnetic moment.A large magnetic moment for the Mn atom is predicted to be 3.81μB.We suggest the ferromagnetic order of the Mn moments and the ferromagnetic coupling to the Ni substrate,which confirms the experimental results.The magnetism of Mn is identified as the driving force of the large buckling and the work-function change.The comparison with the other magnetic surface alloys is also presented and some trends are predicted.     

General formula for phonon-assisted n-photon absorption in solids

A general formula for phonon-assisted n-photon absorption in solids is obtained by (n+1)-th order perturbation technique. The complicated calculation process for transition element of n-photon absorption is simply demonstrated by a diagram approach that is proposed in this work. We find that the transition element for the n-photon absorption has a simple form, i.e., it is just the first term of the n-th order fist kind Bessel function.     

航天相机主动热控测试系统设计

为了检测航天相机主动热控系统的功能、性能及可靠性,设计了主动热控仿真测试系统。依据传热学基本定律、航天器轨道理论和热控策略,给出了计算航天相机温度场的热网络数学模型,使主动热控系统能在模拟的空间热环境中连续工作,实现了对主动热控系统的闭环仿真测试。采用两个数字电位器相串联的方法模拟温度传感器的走势,得到的最大阻值为100 kΩ,精度达到10Ω,符合设计中对总电阻和电阻变化率的需求,实现了对主动热控系统的功能、性能以及可靠性的仿真测试。     

顶空固相微萃取-气相色谱/质谱联用法结合化学计量学分析白肋烟烘焙前后挥发性、半挥发性成分

采用顶空固相微萃取-气相色谱/质谱法（HS-SPME-GC/MS）分析了白肋烟烟叶中挥发性、半挥发性成分。20 mg烟粉在60℃条件下孵化8 min,采用聚二甲基硅氧烷/二乙烯基苯（PDMS/DVB）65 μm纤维头萃取40 min,然后在250℃解吸3 min,通过与标准品和质谱数据库进行比对,初步定性了白肋烟烟叶中122种挥发性、半挥发性成分,并采用内标法进行半定量分析。通过主成分分析（PCA）和偏最小二乘-判别分析（PLS-DA）等化学计量学方法,直观反映了白肋烟烘焙前后挥发性、半挥发性成分的变化。该方法具有样品用量小、前处理简单、灵敏度高等特点,结合化学计量学方法可用于白肋烟烘焙前后化学成分变化分析,为白肋烟烘焙条件的优化提供了科学的检测方法。     

液体燃料熔盐堆三维瞬态耦合分析

根据熔盐堆的流动特性,采用多群扩散理论,建立液体燃料熔盐堆的三维中子动力学模型和流动传热模型,开发针对液体燃料熔盐堆的三维核热耦合程序,并分析瞬态情况下MOSART堆的物理热工特性.结果表明：堆芯热工参数的瞬态变化直接影响物理参数的变化,液体熔盐堆具有较明显的温度负反馈特性.     

Structural, electronic and magnetic properties of the Mnben Ni(110) c(2×2) surface alloy

Using first-principles total energy method, we study the structural, the electronic and the magnetic properties of the MnNi(110) c(2×2) surface alloy. Paramagnetic, ferromagnetic, and antiferromagnetic surfaces in the top layer and the second layer are considered. It turns out that the substitutional alloy in the outermost layer with ferromagnetic surface is the most stable in all cases. The buckling of the Mn–Ni(110) c(2×2) surface alloy in the top layer is as large as 0.26á(1á=0.1 n13) and the weak rippling is 0.038 AA in the third layer, in excellent agreement with experimental results. It is proved that the magnetism of Mn can stabilize this surface alloy. Electronic structures show a large magnetic splitting for the Mn atom, which is slightly higher than that of Mn–Ni(100) c(2×2) surface alloy (3.41 eV) due to the higher magnetic moment. A large magnetic moment for the Mn atom is predicted to be 3.81 μ_B. We suggest the ferromagnetic order of the Mn moments and the ferromagnetic coupling to the Ni substrate, which confirms the experimental results. The magnetism of Mn is identified as the driving force of the large buckling and the work-function change. The comparison with the other magnetic surface alloys is also presented and some trends are predicted.