基于金刚石的量子传感器!中国科大实现千赫兹级谱线分辨率的单自旋顺磁共振

中国科学技术大学杜江峰院士领导的中国科学院微观磁共振重点实验室提出并实验实现了一种基于金刚石氮-空位(NV)色心量子传感器的高分辨顺磁共振探测方法,获得了千赫兹(kHz)谱线分辨率的单自旋顺磁共振谱。该研究成果以“Kilohertz electron paramagnetic resonance spectroscopy of single nitrogen centers at zero magnetic field”为题,发表在《科学进展》上[Science Advances 6:eaaz8244(2020)]。

激光束扫描系统的分辨本领的研究

以高斯光束复曲率半径的复数三角形式和高斯光束菲涅耳数为基础 ,详细分析激光束扫描系统的线分辨率和可分辨光点数 。

激光束受限衍射对扫描系统分辨本领的影响

基于菲涅耳衍射积分公式推导出激光束经扫描元件衍射后场分布表达式,数值分析了激光束经扫描元件后衍射场振幅分布、激光束在扫描面上的光斑半径和激光扫描系统光学分辨本领的大小.结果表明,改变入射光束的束腰半径对激光扫描系统线分辨率、可分辨光点数和分辨容积产生不同的衍射影响.采用近似和拟合方法,分段给出不同衍射情况下激光扫描系统的线分辨率的函数表达式,并通过误差分析证明了近似和拟合函数表达式的精确性.

高精度测温拉曼激光雷达光谱仪的光学设计

为了抑制边缘纯转动拉曼光谱成像偏差,提出了一种高精度测温拉曼激光雷达光谱仪光学系统设计。该系统利用非球面透镜组对光谱仪成像球差进行校正,针对光谱仪10mm/nm的线分辨率要求,采用双光栅结构设计并对测温拉曼光谱仪各参数进行光线追迹,拟合得到双光栅的入射角、准直镜焦距和聚焦镜焦距的最优值。将拟合最优化结果代入Zemax软件进行优化分析,结果显示单个成像光谱成像宽度控制在0.771 5mm,间隔0.1nm的纯转动连续光谱成像中心间隔可以达到1mm,满足了线阵探测器对成像质量的要求。通过计算在J=6级的纯转动拉曼后向散射信号对瑞利-米散射信号实现了108抑制,达到了高精度纯转动拉曼激光雷达测温的目的,解决了目前双光栅光谱技术无法达到提取355nm波段纯转动拉曼高光谱精度的要求,对测温拉曼激光雷达的技术发展有着深远的意义。

多波束侧扫声纳的再认识

多波束侧扫声纳能有效地防止近程和高速扫测时目标遗漏,但国内多波束侧扫技术研究不充分,工作机理分析得不够透彻,且在高速扫测时存在图像质量下降的问题。论文揭示了多波束侧扫声纳工作原理的本质,指出它是采用真实孔径实现合成孔径成像这一重要事实,运用合成孔径声纳的相关理论,讨论了多波束侧扫声纳系统参数的设计,并在合成孔径声纳成像算法的基础上,得到了多波束侧扫声纳逐线成像算法,新算法可以有效地补偿波前弯曲。点目标的仿真结果验证了理论分析和算法的有效性。

是德科技推出增强型FFT应用的12位PCIe高速数据采集卡

直流至高达1.4 GHz带宽,谱线分辨率为97 kHz2016年4月29日,是德科技公司（NYSE：KEYS）日前推出经过增强的FFT选件版本,现已在U5303A PCIe 12位高速数据采集卡上提供。这个板卡拥有两个通道和从1 GS/s到3.2 GS/s的采样率。此卡专为需要进行频域信号处理的天文学、物理学应用和环境测量而设计,使测试人员能够观察到以前的仪器无法观测到的现象,无论是线性度、动态范围还是无杂散动态范围（SFDR）测量都得到了显著改善。

史赛克腹腔镜

史赛克腹腔镜系统以其清晰无比的图像,高质量的系列产品,完善的售后服务,及系统的专业培训计划,保证了内窥镜下胆囊切除术及其他内窥镜下手术的顺利进行,已达到完美的境界。

电沉积光致抗蚀剂——一种制造高密度印制电路板的新技术

航天技术和超级计算机技术的迅猛发展,要求在尽可能小的印制电路板(PCB)上安装尽可能多的元器件,以减小整机的重量和所占的体积,由此给PCB工业带来越来越多严峻的挑战。

4K进化史

看看高分辨率视频是如何改变静态摄影的4K是什么?越来越清晰视频录制的标准和越来越大的显示器……4K格式业界认可的4K标准有很多种,但现在业界较为通用的是超清UHD4K(3,840X2,160像素)和电影Cinema 4K(4,096X2,160像素)长宽比例16:9的"消赞级"全高清UHD 4K格式是现在最常见的宽屏播放比例。1标准分辨宰STANDARD(640X480)标准分标率视频在清晰度上无法与4K视频相比,但是更小更灵活的文件尺寸使得它有了超长的服役时间。

停车场管理系统

天津市普隆科技有限公司专业从事停车场智能管理系统及辅助设施的设计、经销、制造、安装及保养,主要产品包括车库自动管理系统,电动及遥控栏杆(直臂式、折臂式、垂帘式)、行人转闸、反光路锥、广角凸面镜、反光橡胶减速路拱。本公司已为众多写字楼、住宅小区、厂矿企业、政府机关提供了优质的产品及售后服务,倍受广大客户青睐,并成为摩托罗拉(中国)电子有限公司在此领域的专有承包商、供应商。

Joint adaptive waveform and baseline range design for bistatic radar

The problems of joint adaptive waveform design and baseline range design for bistatic radar to maximize the practical radar resolution were considered.Distinguishing from the conventional ambiguity function(AF)-based resolution which is only related with the transmitted waveform and bistatic geometry and could be regarded as the potential resolution of a bistatic radar system,the practical resolution involves the effect of waveform,signal-to-noise ratio(SNR)as well as the measurement model.Thus,it is more practical and will have further significant application in target detection and tracking.The constraint optimization procedure of joint adaptive waveform design and baseline range design for maximizing the practical resolution of bistatic radar system under dynamic target scenario was devised.Simulation results show that the range and velocity resolution are enhanced according to the adaptive waveform and bistatic radar configuration.

Multiple attenuation using λ–f domain high-resolution Radon transform

The parabolic Radon transform has been widely used in multiple attenuation. To further improve the accuracy and efficiency of the Radon transform, we developed the 2- fdomain high-resolution Radon transform based on the fast and modified parabolic Radon transform presented by Abbad. The introduction of a new variable 2 makes the transform operator frequency-independent. Thus, we need to calculate the transform operator and its inverse operator only once, which greatly improves the computational efficiency. Besides, because the primaries and multiples are distributed on straight lines with different slopes in the 2-fdomain, we can easily choose the filtering operator to suppress the multiples. At the same time, the proposed method offers the advantage of high-resolution Radon transform, which can greatly improve the precision of attenuating the multiples. Numerical experiments suggest that the multiples are well suppressed and the amplitude versus offset characteristics of the primaries are well maintained. Real data processing results further verify the effectiveness and feasibility of the method.

Topographic Controls on Alpine Treeline Patterns on Changbai Mountain,China

【Title】【Author】【Addresses】1 The control mechanisms of topography on alpine treeline pattern are critical to understanding treeline dynamics and future changes. These mechanisms have not been understood quite well enough because of increasing human disturbance and low data resolution. In this study, the relationship between the treeline pattern and topography was analyzed based on high spatial resolution remote sensing data and a digital elevation model in an area in Changbai Mountain with little human disturbance. Future treeline patterns were also predicted. The results showed that （a） aspects with high solar radiation and low snow cover have a high coverage rate of trees, （b） the peak coverage rate of trees switches from low slopes （〈5°） to medium slopes （5°~25°） as the elevation rises because of the extreme environment, （c） the coverage rate of trees is a function that depends on environmental factors controlled by topography, （d） the future treeline pattern is controlled by new temperature mechanisms, new environmental factors and the reallocation effect of topography. Our research implies that topography controls the treeline pattern and changes in the treeline pattern associated with global warming, due to the effect of global warming on environmental factors. This study may well explain the causes of heterogeneous changes in the treeline pattern in the horizontal direction as well as differences in treeline response to climate warming.

Snowline and Snow Cover Monitoring at High Spatial Resolution in a Mountainous River Basin Based on a Timelapse Camera at a Daily Scale

Snowline change and snow cover distribution patterns are still poorly understood in steep alpine basins of the Qilian Mountainous region because fast changes in snow cover cannot be observed by current sensing methods due to their short time scale. To address this issue of daily snowline and snow cover observations, a ground- based EOS 7D camera and four infrared digital hunting video cameras （LTL5210A） were installed around the Hulugou river basin （HRB） in the Qilian Mountains along northeastern margin of the Tibetan Plateau （38°15′54″N, 99°52′53″E） in September 2011. Pictures taken with the EOS 7D camera were georeferenced and the data from four LIL521oA cameras and snow depth sensors were used to assist snow cover estimation. The results showed that the time-lapse photography can be very useful and precise for monitoring snowline and snow cover in mountainous regions. The snowline and snow cover evolution at this basin can be precisely captured at daily scale. In HRB snow cover is mainly established after October, and the maximum snow cover appeared during February and March. The consistent rise of the snowline and decrease in snow cover appeared after middle part of March. This melt process is strongly associated with air temperature increase.

MULTI-RESOLUTION LEAST SQUARES SUPPORT VECTOR MACHINES

The Least Squares Support Vector Machines (LS-SVM) is an improvement to the SVM. Combined the LS-SVM with the Multi-Resolution Analysis (MRA),this letter proposes the Multi-resolution LS-SVM (MLS-SVM).The proposed algorithm has the same theoretical framework as MRA but with better approximation ability.At a fixed scale MLS-SVM is a classical LS-SVM,but MLS-SVM can gradually approximate the target function at different scales.In experiments,the MLS-SVM is used for nonlinear system identification,and achieves better identification accuracy.

High resolution 3D nonlinear integrated inversion

The high resolution 3D nonlinear integrated inversion method is based on nonlinear theory. Under layer control, the log data from several wells （or all wells） in the study area and seismic trace data adjacent to the wells are input to a network with multiple inputs and outputs and are integratedly trained to obtain an adaptive weight function of the entire study area. Integrated nonlinear mapping relationships are built and updated by the lateral and vertical geologic variations of the reservoirs. Therefore, the inversion process and its inversion results can be constrained and controlled and a stable seismic inversion section with high resolution with velocity inversion, impedance inversion, and density inversion sections, can be gained. Good geologic effects have been obtained in model computation tests and real data processing, which verified that this method has high precision, good practicality, and can be used for quantitative reservoir analysis.

Comparison of modelled-and remote sensing-derived daily snow line altitudes at Ulugh Muztagh,northern Tibetan Plateau

The ice cap Ulugh Muztagh in the central Kunlun Shan at the northern fringe of the Tibetan Plateau is a very isolated region with arid cold conditions. No observational, meteorological or glaciological ground truth data is available. Using the Moderate-resolution Imaging Spectroradiometer(MODIS) Level 1 radiance Swath Data(MOD02QKM) with a spatial resolution of 250 m, transient snow lines during the months of July to September in 2001 to 2014 are derived. Results are used to calibrate the physical based Coupled Snowpack and Ice surface energy and Mass balance model(COSIMA). The model runs on a representative detail region of Ulugh Muztagh(UM) on a digital elevation model with the same spatial resolution as the MODIS bands. In the absence of field observations, the model is driven solely by dynamically downscaled global analysis data from the High Asia Refined analysis(HAR). We compare remote sensing derived and modelled mean regional transient snow line altitudes in the course of consecutive summer seasons in 2008 to 2010. The resulting snow line altitude(SLA) and annual equilibrium line altitude(ELA) proxy of both methods coincide very well in their interannual variability in accordance with interannual variability of climatic conditions. Since SLAs of both methods do notconsistently agree on a daily basis a usage of remote sensing derived SLAs for model calibration in the absence of field observation data is only limitedly feasible for daily analysis. ELA approximation using the highest SLA at the end of ablation period may not be applied to UM because the negative winter mass balance(MB) is not reflected in the summer SLA. The study reveals moderate negative MB for UM throughout the modelling period. The mean regional MB of UM accounts for-523±410 mm w.e. a-1 in the modelling period. Hence UM seems not to belong to the area of the ‘Karakorum anomaly' comprising a region of positive mass balances in recent years which has its centre presumably in the Western Kunlun Shan.

Hazard and population vulnerability analysis: a step towards landslide risk assessment

In this paper, an attempt to analyse landslide hazard and vulnerability in the municipality of Pahuatlfin, Puebla, Mexico, is presented. In order to estimate landslide hazard, the susceptibility, magnitude （area-velocity ratio） and landslide frequency of the area of interest were produced based on information derived from a geomorphological landslide inventory; the latter was generated by using very high resolution satellite stereo pairs along with information derived from other sources （Google Earth, aerial photographs and historical information）. Estimations of landslide susceptibility were determined by combining four statistical techniques： （i） logistic regression, （ii） quadratic discriminant analysis, （iii） linear discriminant analysis, and （iv） neuronal networks. A Digital Elevation Model （DEM） of lo m spatial resolution was used to extract the slope angle, aspect, curvature, elevation and relief. These factors, in addition to land cover, lithology anddistance to faults, were used as explanatory variables for the susceptibility models. Additionally, a Poisson model was used to estimate landslide temporal frequency, at the same time as landslide magnitude was obtained by using the relationship between landslide area and the velocity of movements. Then, due to the complexity of evaluating it, vulnerability of population was analysed by applying the Spatial Approach to Vulnerability Assessment （SAVE） model which considered levels of exposure, sensitivity and lack of resilience. Results were expressed on maps on which different spatial patterns of levels of landslide hazard and vulnerability were found for the inhabited areas. It is noteworthy that the lack of optimal methodologies to estimate and quantify vulnerability is more notorious than that of hazard assessments. Consequently, levels of uncertainty linked to landslide risk assessment remain a challenge to be addressed.