Deep level transient spectroscopy on charge traps in high-k ZrO2

The deep trap properties of high-dielectric-constant (k) ZrO₂ thin films were examined by deep level transient spectroscopy (DLTS). The hole traps of a ZrO₂ dielectric deposited by sputtering were investigated in a MOS structure over the temperature range, 375 K-525 K. The potential depth, cross section and concentration of hole traps were estimated to be ∼ 2.5 eV, ∼ 1.8 × 10^− 16 cm² and ∼ 1.0 × 10¹⁶ cm^− 3, respectively. DLTS of ZrO₂ dielectrics can be used to examine the threshold voltage shift (?V_th) during the operation of SONOS-type flash memory devices, which employ high-k materials.     

基于RGBD数据与深度权重的压缩光场显示

使用多层空间光调制器的压缩光场(compressive light field,CLF) 显示技术具有空间带宽利用率高、图像分辨率好等优势,是一种很有前景的光场显示技术。传统的方法将光场分解视为超定问题并使用优化算法求解。随着重建光场的分辨率、深度、视角等性能参数的提升,优化算法的计算效率低、内存消耗大的缺陷被放大,难以实现快速计算。为此,本文提出了一种新型CLF分解算法,该算法将原始光场分解为物点进行存储,仅占用少量内存;利用深度权重和加权平均代替了优化算法,大幅提高了运算效率。在同等条件下,所提出的算法占用内存仅是传统方法的38.8%,计算时间缩短了93.7%,图像质量提高约1 dB。最后通过仿真和实验两种方式对比了该方法和传统方法的显示效果,验证了算法的有效性。     

The Role of the Choroid in Stargardt Disease

Stargardt disease is the commonest juvenile macular dystrophy. It is caused by genetic mutations in the ABCA4 gene. Diagnosis is not always straightforward, and various phenocopies exist. Late-onset disease can be misdiagnosed with age-related macular disease. A correct diagnosis is particularly critical because of emergent gene therapies. Stargardt disease is known to affect retinal pigment epithelium and photoreceptors. Many studies have also highlighted the importance of the choroid in the diagnosis, pathophysiology, and progression of the disease. The choroid is in an integral relationship with the retinal pigment epithelium and photoreceptors, and its possible involvement during the disease should be considered. The purpose of this review is to analyze the current diagnostic tools for choroidal evaluation and the extrapolation of useful data for ophthalmologists and researchers studying the disease.     

基于DFB激光器的振动传感系统改进PGC解调算法

相位生成载波(Phase Generated Carrier, PGC)解调算法是目前光纤干涉传感领域中重要的解调算法。针对目前PGC解调算法中光强扰动和调制深度影响信号解调准确度的问题,提出了一种改进的PGC解调算法(PGC-Ameliorated),并搭建了基于分布反馈(Distributed Feedback, DFB)激光器的振动传感系统进行实验验证。实验结果表明,当被测振动信号的频率为800 Hz时,该算法信噪比为57 dB,优于微分交叉相乘(Differential and Cross Multiplying, DCM)算法和反正切(Arctan)算法近20 dB。在不同光强下,该算法解调信号幅值波动范围在±0.02 rad;在不同调制深度下,该算法总谐波失真最小为0.61%,信纳比最大为25.9 dB,相比于DCM算法和Arctan算法具有更低的总谐波失真和更高的信纳比。     

Design and Development of a Bimodal Optical Instrument for Simultaneous Vibrational Spectroscopy Measurements

Vibrational spectroscopy techniques are widely used in analytical chemistry, physics and biology. The most prominent techniques are Raman and Fourier-transform infrared spectroscopy (FTIR). Combining both techniques delivers complementary information of the test sample. We present the design, construction, and calibration of a novel bimodal spectroscopy system featuring both Raman and infrared measurements simultaneously on the same sample without mutual interference. The optomechanical design provides a modular flexible system for solid and liquid samples and different configurations for Raman. As a novel feature, the Raman module can be operated off-axis for optical sectioning. The calibrated system demonstrates high sensitivity, precision, and resolution for simultaneous operation of both techniques and shows excellent calibration curves with coefficients of determination greater than 0.96. We demonstrate the ability to simultaneously measure Raman and infrared spectra of complex biological material using bovine serum albumin. The performance competes with commercial systems; moreover, it presents the additional advantage of simultaneously operating Raman and infrared techniques. To the best of our knowledge, it is the first demonstration of a combined Raman-infrared system that can analyze the same sample volume and obtain optically sectioned Raman signals. Additionally, quantitative comparison of confocality of backscattering micro-Raman and off-axis Raman was performed for the first time.     

岩石切削过程中破坏机制的离散元分析

利用离散单元方法(DEM)对两种不同属性的花岗石样本模型进行了切割模拟,通过调整不同的切削参数计算并分析了岩石切削过程中的切削力、切削深度、切削比能及切削力倾角的变化规律,从细观上探讨了临界切深对岩石脆性破坏模式和塑性破坏模式及其转变的影响,指出了当切削深度逐渐增大时,破坏模式依次从塑性破坏模式到过渡破坏模式最后转变为脆性破坏模式,同时切削力倾角并不随切削深度变化。将离散单元法分析的结果与实际实验进行了比较,表明该方法是合理的。     

同轴式双空心抽油杆下入深度设计方法

同轴式双空心抽油杆加热系统可有效解决高凝油井井筒易结蜡、稠油井产液黏度较高的问题,但考虑油井生产效率、开采成本及综合的经济效益,需要计算出最佳的抽油杆下入深度。以井口出油温度最优为目标,同轴式双空心抽油杆下入深度、循环水进口温度为约束条件,建立了井口出油温度C计算模型。利用该模型进行求解时,先用迭代法进行同轴式双空心抽油杆下入深度优化,然后在优化结果基础上进行抽油机载荷校核。建立的井口出油温度计算模型及同轴式双空心抽油杆下入深度确定方法,在现场13口油井进行了应用。结果表明,该方法避免了以前设计人员凭经验确定抽油杆下深的弊端,可靠性更高,且有效时率平均提高14.1百分点,既满足了生产需要又节省了油井开发成本。      

基于电磁感应的钢筋定位及埋深检测新方法研究

钢筋混凝土结构广泛运用于电力基础设施中,对其内部钢筋参数进行检测能够有效判断其结构耐久性,对保障电力系统安全稳定运行有重要的意义。针对传统钢筋混凝土检测方法无法判断混凝土内钢筋走向及埋深测量不够精确的问题,通过对钢筋测量原理分析和霍尔传感器布局设计,提出了一种基于电磁感应的钢筋定位及埋深检测方法。该方法用于判断钢筋的中心位置并测量其偏转角度,同时利用拟合得到的函数反应检测值与钢筋埋深之间的关系。实验表明,埋深检测值受到相邻钢筋的影响而存在较大误差,间距越小误差越大,因此通过BP（Back propagation）神经网络对不同间距下的检测值进行了数据修正,有效地提高了混凝土中钢筋埋深的检测精度。     

埋地热油管道埋深对土壤温度场的影响

长输管道沿线地质、水文等条件不同,管道埋深差别较大。相应埋深处的自然地温及管道周围的温度场也不同。若只考虑平均或当量深度来进行管道计算,会产生很大误差。使用数值方法将所考虑的数值模型更接近于实际冻土地质条件和非线性特性就显得格外重要。采用有限单元法,对不同埋深条件下的管道周围土壤温度场进行三维数值计算,结果表明,管道温度变化在一定程度上受埋深影响,尤其在冻土地区,地埋温差与管道周围土壤温差较大。     

基于相关算法的海缆埋深检测性能分析

基于信号和噪声统计不相关特性,提出了相关算法在海缆埋深检测中的新应用,并结合IIR（无限脉冲冲击响应）滤波算法进行了分析比较。当幅值为1 V的25 Hz探测信号分别受到幅值为100 V的20.15 Hz,24.45 Hz强噪声干扰时,相关算法滤波后得到的归一化幅值分别为1.185和5.870,而IIR滤波算法得到的归一化幅值为1.42和9.32。仿真结果表明,海缆探测中相关算法优于IIR滤波算法。