EFFECTIVE DETECTION DEPTH OF NEEDLE-LIKE OPTICAL PROBE

The effective detection depth of the needle-like optical probe is studied. The light transport model in highly scattering tissue is the diffusion equation and the boundary is Neuman. The sensitivity matrix is related to the position of the light source and the detector. It can be used to evaluate the effective detection depth. The sensitivity matrix is defined as the multiplication of the source and detector hght distribution. Six different groups about ix parameters including the source diameter and detector fibers, the core-to-core distance between the source and detector fibers, the opotode depth, the absorption, and reduced scattering coefficient, are used as experimental models. The relationship between the six parameters and the effective detection depth is analyzed. Resuits can be used to study the spatial resolution and the depth of multi-fibers.

Experimental Detection of Depth of Field for a Thermal Light Lensless Ghost Imaging System

We propose optical experiments to study the depth of field for a thermal light lensless ghost imaging system. It is proved that the diaphragm is an important factor to influence the depth of field, and the ghost images of two detected objects with longitudinal distance less than the depth of field can be achieved simultaneously. The longitudinal coherence scale of the thermal light lensless ghost imaging determines the depth of field. Theoretical analysis can well explain the experimental results.

Bioinspired Adaptive,Elastic,and Conductive Graphene Structured Thin-Films Achieving High-Efficiency Underwater Detection and Vibration Perception

Underwater exploration has been an attractive topic for understanding the very nature of the lakes and even deep oceans.In recent years,extensive efforts have been devoted to developing functional materials and their integrated devices for underwater information capturing.However,there still remains a great challenge for water depth detection and vibration monitoring in a high-efficient,controllable,and scalable way.Inspired by the lateral line of fish that can sensitively sense the water depth and environmental stimuli,an ultrathin,elastic,and adaptive underwater sensor based on Ecoflex matrix with embedded assembled graphene sheets is fabricated.The graphene structured thin film is endowed with favourable adaptive and morphable features,which can conformally adhere to the structural surface and transform to a bulged state driven by water pressure.Owing to the introduction of the graphene-based layer,the integrated sensing system can actively detect the water depth with a wide range of 0.3-1.8 m.Furthermore,similar to the fish,the mechanical stimuli from land(e.g.knocking,stomping)and water(e.g.wind blowing,raining,fishing)can also be sensitively captured in real time.This graphene structured thin-film system is expected to demonstrate significant potentials in underwater monitoring,communication,and risk avoidance.

Laser ultrasonic technique for surface defects detection of 6061 aluminum alloy

In order to estimate and detect the surface defect depth of metals, the transmission method of laser ultrasonic surface waves is used in this work. The laser ultrasonic detection platform taking use of thermoelastic mechanism as acoustic signal excitation method and interference receiver as acoustic signal receiver method was built, by which B-scan images of detected specimens with surface defects were collected to establish the relationship between the transmission coefficient and depth of the surface defect. Experimental results show that the amplitude of transmitted acoustic signal is related to the depth of surface defect. At last, a fitted curve of transmission coefficient using measured experimental data is obtained to estimate depth of surface defect on the 6061 aluminum alloy. Furthermore, a surface defect depth of 0.3 mm is estimated by the fitting curve with an estimated error of 16%. Therefore, a experimental method using the transmission method by laser ultrasonic is presented in this paper.

Detection of crevasses over polar ice shelves using Satellite Laser Altimeter

Ice shelf breakups account for most mass loss from the Antarctic Ice Sheet as the consequence of the propagation of crevasses(or rift)in response to stress.Thus there is a pressing need for detecting crevasses’location and depth,to understand the mechanism of calving processes.This paper presents a method of crevasse detection using the ICESat-1/GLAS data.A case study was taken at the Amery Ice Shelf of Antarctica to verify the accuracy of geo-location and depth of crevasses detected.Moreover,based on the limited crevasse points,we developed a method to detect the peak stress points which can be used to track the location of the crack tips and to identify the possible high-risk area where an ice shelf begins to break up.The spatial and temporal distribution of crevasse depth and the spatial distribution of peak stress points of the Amery Ice Shelf were analyzed through 132 tracks in 16 campaign periods of ICESat-1/GLAS between 2003 and 2008.The results showed that the depth of the detected crevasse points ranged from 2 to 31.7 m,which were above the sea level;the crevasse that advected downstream to the front edge of an ice shelf has little possibility to directly result in breakups because the crevasse depth did not show any increasing trend over time;the local stress concentration is distributed mainly in the suture zones on the ice shelves.

Influence of computation algorithm on the accuracy of rut depth measurement

Rutting is one of the dominant pavement distresses, hence, the accuracy of rut depth measurements can have a substantial impact on the maintenance and rehabilitation （M 8： R） strategies and funding allocation. Different computation algorithms such as straight- edge method and wire line method, which are based on the same raw data, may lead to rut depth estimation which are not always consistent. Therefore, there is an urgent need to assess the impact of algorithm types on the accuracy of rut depth computation. In this paper, a 1B-point-based laser sensor detection technology, commonly accepted in China for rut depth measurements, was used to obtain a database of 85,000 field transverse profiles having three representative rutting shapes with small, medium and high severity rut levels. Based on the reconstruction of real transverse profiles, the consequences from two different algorithms were compared. Results showed that there is a combined effect of rut depth and profile shape on the rut depth computation accuracy. As expected, the dif- ference between the results obtained with the two computation methods increases with deeper rutting sections： when the distress is above 15 mm （severe level）, the average dif- ference between the two computation methods is above 1.5 mm, normally, the wire line method provides larger results. The computation suggests that the rutting shapes have a minimal influence on the results. An in-depth analysis showed that the upheaval outside of the wheel path is a dominant shape factor which results in higher computation differences.

Anomalous self-optimization of sulfate ions for boosted oxygen evolution reaction

Broadly,the oxygen evolution reaction(OER)has been deeply understood as a significant part of energy conversion and storage.Nevertheless,the anions in the OER catalysts have been neglected for various reasons such as inactive sites,dissolution,and oxidation,amongst others.Herein,we applied a model catalyst s-Ni(OH)2 to track the anionic behavior in the catalyst during the electrochemical process to fill this gap.The advanced operando synchrotron radiation Fourier transform infrared(SR-FTIR)spectroscopy,synchrotron radiation photoelectron spectroscopy(SRPES)depth detection and differential X-ray absorption fine structure(D-XAFS)spectrum jointly point out that some oxidized sulfur species(SO_(4)^(2-))will selfoptimize new Ni–S bonds during OER process.Such amazing anionic self-optimization(ASO)behavior has never been observed in the OER process.Subsequently,the optimization-derived component shows a significantly improved electrocatalytic performance(activity,stability,etc.)compared to reference catalyst Ni(OH)_(2).Theoretical calculation further suggests that the ASO process indeed derives a thermodynamically stable structure of the OER catalyst,and then gives its superb catalytic performance by optimizing the thermodynamic and kinetic processes in the OER,respectively.This work demonstrates the vital role of anions in the electrochemical process,which will open up new perspectives for understanding OER and provide some new ideas in related fields(especially catalysis and chemistry).