Temperature Sensitivity Control and Mechanical Stress Effect of Boron-Doped Long-Period Fiber Gratings

We will present in this work the quantitative analysis of the relationship between the doping concentrations of GeO 2 and B 2 O 3 in the core and cladding regions and the temperature sensitivity of the resonance wavelength shift in long-period fiber gratings (LPFGs). Based on this analysis, the temperature sensitivity was suppressed and enhanced to 0.002 nm/C and 0.28 nm/C, respectively. We will also discuss the effect of the residual mechanical stress on the optical and mechanical properties of LPFGs. In particular, we will present the measurement results of the dependence of the refractive index change and mechanical strength on the residual mechanical stress in the boron-doped fibers with depressed clad and matched clad.     

Absorption intensities for the 4-0 through 7-0 overtone bands of HCl

We have measured the absorption intesities for a number of rotation-vibration lines in the 4-0 through 7-0 overtone bands of HCl utilizing a Fourier transform spectrometer and a 409.6 m path length White cell. Individual line strengths, band strengths, dipole matrix elements, and Herman-Wallis factors are presented.     

Asymptotic Error Expansion for the Nystrom Method of Nonlinear Volterra Integral Equation of the Second Kind

1.IntroductionConsiderthenonlinearVolterraintegraJequationofthesecondkindHere,u(x)isanunknownfunction,f(x)andK(x,t,u)aregivencontinuousfunctionsdefined,respectively,on[a,b1andD={(x,t,u):aSx5b,aSt5x)-oc相似文献   

矩形域上散乱数据多元最优插值的误差估计及其超收敛性（Ⅰ）──带连续边界条件

本文我们讨论了矩形域上带连续边界条件的一类多元散乱数据最优插值。给出了某些情形插值的误差估计，误差估计表明在某些点上还具有超收敛性。     

奇异积分方程理论在迁移方程中的应用

本文利用奇异积分方程理论，对于具有非零边界条件的球对称模型的散射裂为函数，给出了直接求妥方法并给出了解的明显表达式。     

用于SCA ASIC测试的数字读出模块设计

高速开关电容阵列(SCA)具有高速采样、低功耗的特点,基于SCA的高速波形数字化是目前高精度时间测量的一个重要研究方向。为此,我们开展SCA芯片的研究,目前已设计完成原型ASIC设计,并正在进行后续版本的改进设计。为便于未来多版本ASIC的测试和评估,需设计具有一定通用性的数字读出模块,本论文工作主要介绍此模块的设计工作以及相应的数据读出软件。数字读出模块基于FPGA实现对待测ASIC的控制、配置及数据读出,采用DDR3片外存储芯片,使用USB3.0等接口进行数据传输;上位机软件基于Python3.7设计,实现了数据采集与波形绘制等功能。目前已使用设计完成的数字读出模块对第2版SCA ASIC进行了初步的测试,测试结果表明,此读出模块工作正常,且SCA芯片输出结果符合预期。     

An improved evaluation of the neutron background in the PandaX-Ⅱ experiment

In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively.     

具有高隔离度的双陷波超宽带多入多出天线

提出了一款具有高隔离度的双陷波超宽带多入多出（UWB MIMO）天线。该天线由两个相同的半切超宽带天线单元倒置构成。通过在天线底板刻蚀栅栏型缺陷地解耦结构,使该MIMO天线的隔离度提高至25 dB。此外,在天线半圆形辐射贴片上刻蚀两个方向相反的“L”型缝隙,实现了双陷波的功能,分别抑制了802.16无线城域网WiMAX（3.2～3.7 GHz）和WLAN（5.15～5.85 GHz）信号对天线系统的干扰。实验结果表明,该天线在3～11 GHz工作带宽内的隔离度大于25 dB,包络相关系数（ECC）小于0.004;第一个陷波频段为3.0～3.7 GHz,第二个陷波频段为5.1～5.85 GHz,有效抑制了WiMAX和WLAN的信号干扰。     

Predicting Quantum Many-Body Dynamics with Transferable Neural Networks

Advanced machine learning(ML)approaches such as transfer learning have seldom been applied to approximate quantum many-body systems.Here we demonstrate that a simple recurrent unit(SRU)based efficient and transferable sequence learning framework is capable of learning and accurately predicting the time evolution of the one-dimensional(ID)Ising model with simultaneous transverse and parallel magnetic fields,as quantitatively corroborated by relative entropy measurements between the predicted and exact state distributions.At a cost of constant computational complexity,a larger many-body state evolution is predicted in an autoregressive way from just one initial state,without any guidance or knowledge of any Hamiltonian.Our work paves the way for future applications of advanced ML methods in quantum many-body dynamics with knowledge only from a smaller system.     

改变激发环境调控Ho3+离子的上转换发光特性

稀土掺杂上转换发光材料的发光特性不仅依赖于基质材料本身,而且与其激发条件密切相关.本文主要是以Ho^3+离子为研究对象,在NaYF4和LiYF4这两种不同的基质中,研究其在不同激发条件下的上转换发光特性.通过共聚焦显微光谱测试系统,对比Ho^3+离子在NaYF4和LiYF4微米晶体中的发光特性.实验结果发现:Ho^3+离子在这两种不同基质中均展现出较强的荧光发射.然而,当激发功率增加时,在单颗粒个LiYF4微米晶体中,当激发功率增加时,Ho^3+离子则发射出较强绿光及微弱的红光,红绿比变化并不明显,其蓝光发射强度也相对较弱.当激发这两种微米粉末晶体时,结果发现:Ho^3+离子均发射较强的绿光发射并伴有微弱红光发射,两种晶体中的发射特性极其相似.由此可见,在常规测试条件下,一些特殊发光现象是很难被观测到的.同时,通过对其光谱特性的分析,对Ho^3+离子的发光机理进行了研究.