Improvement of Binocular Reconstruction Algorithm for Measuring 3D Pavement Texture Using a Single Laser Line Scanning Constraint

The dense and accurate measurement of 3D texture is helpful in evaluating the pavement function.To form dense mandatory constraints and improve matching accuracy,the traditional binocular reconstruction technology was improved threefold.First,a single moving laser line was introduced to carry out global scanning constraints on the target,which would well overcome the difficulty of installing and recognizing excessive laser lines.Second,four kinds of improved algorithms,namely,disparity replacement,superposition synthesis,subregion segmentation,and subregion segmentation centroid enhancement,were established based on different constraint mechanism.Last,the improved binocular reconstruction test device was developed to realize the dual functions of 3D texture measurement and precision self-evaluation.Results show that compared with traditional algorithms,the introduction of a single laser line scanning constraint is helpful in improving the measurement’s accuracy.Among various improved algorithms,the improvement effect of the subregion segmentation centroid enhancement method is the best.It has a good effect on both overall measurement and single pointmeasurement,which can be considered to be used in pavement function evaluation.

Analysis of deformation mechanisms in magnesium single crystals using a dedicated four-point bending tester

In this study,we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending tester.We prepared two single-crystal samples,oriented along the<1120>and<1010>directions,to assess the mechanisms of deformation when the initial basal slip was suppressed.In the<1120>sample,the primary{1012}twin(T1)was confirmed along the<1120>direction of the sample on the compression side with an increase in bending stress.In the<1010>sample,T1 and the secondary twin(T2)were confirmed to be along the<1120>direction,with an orientation of±60°with respect to the bending stress direction,and their direction matched with(0001)in T1 and T2.This result implies that crystallographically,the basal slip occurs readily.In addition,the<1010>sample showed the double twin in T1 on the compression side and the tertiary twin along the<1010>direction on the tension side.These results demonstrated that the maximum bending stress and displacement changed significantly under the bend loading because the deformation mechanisms were different for these single crystals.Therefore,the correlation between bending behavior and twin orientation was determined,which would be helpful for optimizing the bending properties of Mg-based materials.

A Hybrid Optimization Approach of Single Point Incremental Sheet Forming of AISI 316L Stainless Steel Using Grey Relation Analysis Coupled with Principal Component Analysiss

We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response.

Compensation of body shake errors in terahertz beam scanning single frequency holography for standoff personnel screening

In the terahertz（THz） band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed.

Scanning probe lithography on calixarene towards single-digit nanometer fabrication

Cost effective patterning based on scanning probe nanolithography(SPL)has the potential for electronic and optical nano-device manufacturing and other nanotechnological applications.One of the fundamental advantages of SPL is its capability for patterning and imaging employing the same probe.This is achieved with self-sensing and self-actuating cantilevers,also known as‘active'cantilevers.Here we used active cantilevers to demonstrate a novel path towards single digit nanoscale patterning by employing a low energy(<100 eV)electron exposure to thin films of molecular resist.By tuning the electron energies to the lithographically relevant chemical resist transformations,the interaction volumes can be highly localized.This method allows for greater control over spatially confined lithography and enhances sensitivity.We found that at low electron energies,the exposure in ambient conditions required approximately 10 electrons per single calixarene molecule to induce a crosslinking event.The sensitivity was 80-times greater than a classical electron beam exposure at 30 keV.By operating the electro-exposure process in ambient conditions a novel lithographic reaction scheme based on a direct ablation of resist material(positive tone)is presented.

Evaluation of Single Field Uniform Dose (SFUD) Proton Pencil Beam Scanning (PBS) Planning Strategy for Lung Mobile Tumor Using a Digital Phantom

Purpose: To quantitatively evaluate four different Proton SFUD PBS initial planning strategies for lung mobile tumor. Methods and Materials: A virtual lung patient’s four-dimensional computed tomography (4DCT) was generated in this study. To avoid the uncertainties from target delineation and imaging artifacts, a sphere with diameter of 3 cm representing a rigid mobile target (GTV) was inserted into the right side of the lung. The target motion is set in superior-inferior (SI) direction from ?5 mm to 5 mm. Four SFUD planning strategies were used based on: 1) Maximum-In-tensity-Projection Image (MIP-CT);2) CT_average with ITV overridden to muscle density (CTavg_muscle);3) CT_average with ITV overridden to tumor density (CTavg_tumor);4) CT_average without any override density (CTavg_only). Dose distributions were recalculated on each individual phase and accumulated together to assess the “actual” treatment. To estimate the impact of proton range uncertainties, +/?3.5% CT calibration curve was applied to the 4DCT phase images. Results: Comparing initial plan to the dose accumulation: MIP-CT based GTV D98 degraded 2.42 Gy (60.10 Gy vs 57.68 Gy). Heart D1 increased 6.19 Gy (1.88 Gy vs 8.07 Gy);CTavg_tumor based GTV D98 degraded 0.34 Gy (60.07 Gy vs 59.73 Gy). Heart D1 increased 2.24 Gy (3.74 Gy vs 5.98 Gy);CTavg_muscle based initial GTV D98 degraded 0.31 Gy (60.4 Gy vs 60.19 Gy). Heart D1 increased 3.44 Gy (4.38 Gy vs 7.82 Gy);CTavg_only based Initial GTV D98 degraded 6.63 Gy (60.11 Gy vs 53.48 Gy). Heart D1 increased 0.30 Gy (2.69 Gy vs 2.96 Gy);in the presence of ±3.5% range uncertainties, CTavg_tumor based plan’s accumulated GTV D98 degraded to 57.99 Gy (+3.5%) 59.38 Gy (?3.5%), and CTavg_muscle based plan’s accumulated GTV D98 degraded to 59.37 Gy (+3.5%) 59.37 Gy (?3.5%). Conclusion: This study shows that CTavg_Tumor and CTavg_Muscle based planning strategies provide the most robust GTV coverage. However, clinicians need to be aware that the actual dose to OARs at distal end of target may increase. The study also indicates that the current SFUD PBS planning strategy might not be sufficient to compensate the CT calibration uncertainty.

黏结剂Single bond 2不同涂布方式下人牙本质黏结界面的环境扫描电镜观察

目的:比较黏结剂S ingle bond 2不同涂布方式下牙本质黏结界面的形态学变化,为临床选择黏结剂应用方法提供参考依据。方法:暴露新鲜拔除的人第三磨牙牙本质,应用不同方式(包括涂布力度、方向、层数和固化次数)分组进行黏结剂涂布,然后,在环境扫描电镜下直接观察牙本质黏结界面的形态差异。根据黏结剂分布是否均匀、封闭牙本质小管的程度以及黏结剂渗入牙本质小管的情况判断效果。结果:黏结剂涂布力度方面,轻涂比重涂好;涂布方向,同向涂布比反复涂布好;涂布层数,涂2层较涂1层或4层好;固化方式,固化1次较固化2次好。结论:临床使用第五代黏结剂S ingle bond 2时,推荐同向轻涂2遍后固化的方法,可使黏结剂均匀分布,并较好地封闭牙本质小管。

Manipulation and control of a single molecular rotor on Au(111) surface

Three different methods are used to manipulate and control phthalocyanine based single molecular rotors on Au （111） surface： （1） changing the molecular structure to alter the rotation potential; （2） using the tunnelling current of the scanning tunnelling microscope （STM） to change the thermal equilibrium of the molecular rotor; （3） artificial manipulation of the molecular rotor to switch the rotation on or off by an STM tip. Furthermore, a molecular ＇gear wheel＇ is successfully achieved with two neighbouring molecules.

Interaction of CO and O2 with Supported Pt Single-Atoms on TiO2(110)

In view of the high activity of Pt single atoms in the low-temperature oxidation of CO,we investigate the adsorption behavior of Pt single atoms on reduced rutile TiO2(110)surface and their interaction with CO and O2 molecules using scanning tunneling microscopy and density function theory calculations.Pt single atoms were prepared on the TiO2(110)surface at 80 K,showing their preferred adsorption sites at the oxygen vacancies.We characterized the adsorption configurations of CO and O2 molecules separately to the TiO2-supported Pt single atom samples at 80 K.It is found that the Pt single atoms tend to capture one CO to form Pt-CO complexes,with the CO molecule bonding to the fivefold coordinated Ti(Ti5 c)atom at the next nearest neighbor site.After annealing the sample from 80 K to 100 K,CO molecules may diffuse,forming another type of complexes,Pt-(CO)2.For O2 adsorption,each Pt single atom may also capture one O2 molecule,forming Pt-O2 complexes with O2 molecule bonding to either the nearest or the next nearest neighboring Ti5c sites.Our study provides the single-molecule-level knowledge of the interaction of CO and O2 with Pt single atoms,which represent the important initial states of the reaction between CO and O2.

Visualization of atomic scale reaction dynamics of supported nanocatalysts during oxidation and ammonia synthesis using in-situ environmental(scanning) transmission electron microscopy

Reaction dynamics in gases at operating temperatures at the atomic level are the basis of heterogeneous gas-solid catalyst reactions and are crucial to the catalyst function.Supported noble metal nanocatalysts such as platinum are of interest in fuel cells and as diesel oxidation catalysts for pollution control,and practical ruthenium nanocatalysts are explored for ammonia synthesis.Graphite and graphitic carbons are of interest as supports for the nanocatalysts.Despite considerable literature on the catalytic processes on graphite and graphitic supports,reaction dynamics of the nanocatalysts on the supports in different reactive gas environments and operating temperatures at the single atom level are not well understood.Here we present real time in-situ observations and analyses of reaction dynamics of Pt in oxidation,and practical Ru nanocatalysts in ammonia synthesis,on graphite and related supports under controlled reaction environments using a novel in-situ environmental(scanning) transmission electron microscope with single atom resolution.By recording snapshots of the reaction dynamics,the behaviour of the catalysts is imaged.The images reveal single metal atoms,clusters of a few atoms on the graphitic supports and the support function.These all play key roles in the mobility,sintering and growth of the catalysts.The experimental findings provide new structural insights into atomic scale reaction dynamics,morphology and stability of the nanocatalysts.

SPM analysis on groups of single aerosol particles around steel plant

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Growth, Crystal Structure and Characterization of a New Single Crystal: Lithium Sodium Acid Phthalate (LiNaP), for Third Order Nonlinear Optical Applications

A new alkali metallo-organic single crystal of Lithium Sodium Acid Phthlate (LiNaP) complex has been synthesized from aqueous solution in the equimolar ratio 3:1:2. Transparent and bulk single crystals of dimension 9 × 4 ×2 mm3 have been grown from the conventional slow-cooling technique. The crystal structure of the compound has been solved from single crystal X-ray diffraction. The compound 2[C8H4O3]4-Li3+Na+ crystallizes in triclinic system with a space group of Pī having cell dimensions a = 7.5451(2) ? b = 9.8422(3) ? c = 25.2209(7) ? α = 80.299(2);β = 89.204(2);γ = 82.7770(10). FTIR measurement was carried out fo? LiNaP to study the vibrational structure of the compound. The various functional groups present in the molecule and the role of H-bonds in stabilizing the crystal structure of the compound have been explained. Optical absorption properties were studied for the grown crystal using UV-Vis-NIR spectrum. Thermal measurements were carried out for LiNaP to determine the thermal strength as well as to ascertain the hydrated nature of the crystal. Third order nonliner optical studies have also studied by Z-scan techniques. Nonlinear absorption and nonlinear refractive index were found out and the third order bulk susceptibility of compound was also estimated. The results of all studies have been discussed in detail.

Compact and effective photon-resolved image scanning microscope

Fluorescence confocal laser-scanning microscopy(LSM)is one of the most popular tools for life science research.This popularity is expected to grow thanks to single-photon array detectors tailored for LSM.These detectors offer unique single-photon spatiotemporal information,opening new perspectives for gentle and quantitative superresolution imaging.However,a flawless recording of this information poses significant challenges for the microscope data acquisition(DAQ)system.We present a DAQ module based on the digital frequency domain principle,able to record essential spatial and temporal features of photons.We use this module to extend the capabilities of established imaging techniques based on single-photon avalanche diode(SPAD)array detectors,such as fluorescence lifetime image scanning microscopy.Furthermore,we use the module to introduce a robust multispecies approach encoding the fluorophore excitation spectra in the time domain.Finally,we combine time-resolved stimulated emission depletion microscopy with image scanning microscopy,boosting spatial resolution.Our results demonstrate how a conventional fluorescence laser scanning microscope can transform into a simple,information-rich,superresolved imaging system with the simple addition of a SPAD array detector with a tailored data acquisition system.We expected a blooming of advanced single-photon imaging techniques,which effectively harness all the sample information encoded in each photon.

实现生物单分子成像的液相扫描电镜新技术

细胞膜蛋白的定位和分布在疾病发生发展中起着重要的作用,而原位表征纳米级膜蛋白需要单分子水平技术。为实现生物样品的原位液态环境高分辨成像,发展了一套基于扫描电镜液体环境的单分子成像技术。该技术采用扫描透射成像装置和商业化液体芯片装置组合,利用该技术观察了三阴性乳腺癌细胞膜蛋白表皮生长因子受体的精确定位、分布和聚合态。结果表明,采用高真空环境大约10~(-4) Pa、加速电压30 kV、束流约10~(-10) A实验参数,液体环境扫描透射成像模式,图像分辨率达到2~3 nm。标定膜蛋白的量子点ZnS@CdSe和Au纳米颗粒,具有相对于生物和液体更高的原子序数,因此在成像中形成了更好的衬度和信噪比。该技术为解决细胞生物学领域的高分辨单分子成像提供了一种先进的原位研究方法和直观观测平台。

MSP430单片机中SCAN IF模块在流量检测中的应用

介绍了利用LC传感器实现旋转运动测量的原理,阐述了用MSP430单片机中的SCAN IF模块实现流量检测的设计.

光谱CT单期增强扫描鉴别左心耳血栓与血流淤滞的临床初探

目的:评估光谱CT单期增强检查对于鉴别左心耳血栓和血流淤滞的应用价值。方法:回顾性收集2021年9月至2023年3月因房颤在我院行左心房CT血管成像检查的患者共86例。每例患者均在Philips IQON Spectral CT接受双期增强扫描;以双期增强扫描诊断结果为参考标准,定量测量单期左心耳充盈缺损区碘浓度。采用独立样本t检验比较血栓及血流淤滞处碘浓度的差异。结果:入组患者22例,其中诊断为左心耳血栓2例,诊断为血流淤滞16例,诊断为血栓合并血流淤滞4例。增强第一期图像生成的碘浓度图中,血栓处碘浓度[(0.68±0.47)mg/mL]明显低于血流淤滞处[(3.51±1.25)mg/mL,P<0.001],经过受试者工作特征曲线分析得到截断值1.80 mg/mL时有较高鉴别诊断效能。结论:光谱CT单期增强扫描碘浓度测定可帮助鉴别左心耳血栓和血流淤滞。

基于煤层结构数字井筒反演的有机质丰度评价方法及应用

煤层气是典型的自生自储型气藏类型之一,甲烷气体主要由煤层中的有机碳热演化生成并大量吸附于孔隙表面,有机成分的含量对于煤层生气及储气能力十分重要。但煤层气储层结构复杂,有机煤岩和无机夹矸层交互叠置发育,层内非均质性强,单井纵向煤层结构可视化难度大,制约了煤层气单井有机质丰度评价及高效开发。全直径CT扫描是近年来针对大尺度岩心的一种重要实验技术,应用该技术扫描得到的煤岩灰度值与其构成关系密切,灰度值越高则煤岩灰分、密度以及矿物含量越高,反之则越低。以大宁—吉县区块目的煤层为研究对象,通过全直径CT扫描技术与测井解释技术相结合,探究了岩石灰度与伽马、密度以及声波时差等测井数据的关系,建立了煤层结构数字井筒反演数学模型,并结合灰度与有机组分的关系,提出了全直径CT扫描单井有机质丰度评价方法。将研究区A1井反演获得的纵截面与全直径CT扫描真实灰度截面对比,二者相似度高,反演灰度值与CT真实灰度值散点图分布规律一致,表明反演模型能够有效反映煤层内部非均质性结构变化。数字井筒反演及有机质丰度评价方法可为研究区煤层气井压裂选段及产能预测提供有力的技术支撑。

天津大神堂海洋牧场人工鱼礁沉陷现状调查研究

人工鱼礁建设可为海洋生态系统改善和渔业资源增殖做出重要贡献,但由于海床底质、水流风浪等因素影响,鱼礁礁体可能发生沉陷现象,严重影响其生态功能。本研究聚焦天津大神堂海洋牧场,基于侧扫声呐、单波束测深仪、差分式GPS、智能无人船、ArcGIS等设备和软件,对海洋牧场人工鱼礁沉陷状况进行了调查和分析,并对沉陷的影响因素进行了初步探讨。结果表明,天津大神堂海洋牧场中人工鱼礁保存现状较好,大多数礁体呈现竖置状态,平均沉陷深度为0.38 m,沉陷比例约25.43%,生态修复和渔业资源增殖功能未受重大影响;人工鱼礁沉陷情况与礁体坐底时长、海床底质密切相关。本研究采用的人工鱼礁沉陷调查方式具有较强的可行性,研究成果可为海洋牧场人工鱼礁建设的规划选址提供科学依据和技术支撑。

Incidence of exclusive extrapelvic skeletal metastasis in prostate carcinoma on bone scintigraphy

BACKGROUND Bone is one of the common sites of metastasis from prostate carcinoma.Bone scintigraphy(BS)is one of the most sensitive imaging modalities currently used for bone metastatic work-up.Skeletal metastasis in prostate carcinoma commonly involves pelvic bones but rarely involves extrapelvic-extraspinal sites.AIM To retrospectively analyze the BS data to determine the pattern of skeletal metastases in the prostate carcinoma.METHODS This retrospective observational study involves patients with biopsy-proven prostate carcinoma referred for BS for staging assessment.Patients with abnormal BS were evaluated for the pattern of skeletal involvement and data were pre-sented in descriptive format in the form of percentages.RESULTS A total of 150 patients with biopsy-proven prostate cancer who were referred for staging were included in the study.Thirteen of 150 patients(8.67%)had no abnormal uptake on planar images,ruling out metastatic disease.Twenty-four patients(16%)had heterogeneous uptake in the spine with distribution charac-teristic of degenerative disease and no scan pattern of metastatic disease.Thirty patients(20%)had multifocal uptake involving both pelvic and extra pelvic bones on planar images typical for skeletal metastasis and were considered metastatic.Eighty-three out of 150 patients(55.3%)had increased tracer uptake,which was indeterminate,thus,single photon emission computed tomography-computed tomography(SPECT-CT)was acquired,which showed 51 with metastatic disease,31 benign lesions,and one indeterminate finding.Seven of 150 patients had exclusive pelvic bone uptake,which was found to be metastatic in 4/7 patients in SPECT-CT.Fifty six out of 150 patients showed exclusive extrapelvic tracer uptake,of which only 3 had vertebral metastatic disease.None of the patients with increased uptake exclusively in the extrapelvic-extraspinal location was metastatic.CONCLUSION The incidence of exclusive extrapelvic skeletal metastatic disease in prostate carcinoma is 2%(excluding one patient with indeterminate findings).Further,none of the patients in the current study had exclusive extrapelvic-extraspinal metastasis.Thus,exclusive extrapelvic-extraspinal focal abnormality on planar BS carries a very low probability of metastatic disease and hence,further imaging or SPECT-CT can be safely avoided in such cases.

基于Zigbee技术的小车勘测系统设计

为应对各类管道勘测的需要,设计了一种具有勘测技术的小车以解决具体需求。该小车以STM32作为核心控制器,配备红外气体传感器来检测管道内二氧化碳等气体浓度、温湿度传感器来检测管道内的温湿度以及激光扫描技术提供管道内表面的三维图像。最后,将所检测的数据通过Zigbee技术无线传输到PC端或手机上。