Research on 3D Laser Scanning Reconstruction of Ancient Buildings Combined with BIM Technology

After more than 30 years of scientific and social development, surveying and mapping technology by leaps and bounds, engineering surveying technology has undergone tremendous changes. In the process of protecting ancient buildings, it is necessary to obtain the precise dimensions of architectural details. In this study, the path of 3D laser scanning combined with BIM technology is explored. Taking the observation and protection of the ancestral hall of the Liu family as an example, this study aims to draw drawings that reflect the relevant information about the ancient buildings, the accurate three-dimensional model of ancient buildings is established with BIM technology, which provides new methods and ideas for the research and protection of ancient buildings. .

Indoor Space Modeling and Parametric Component Construction Based on 3D Laser Point Cloud Data

In order to enhance modeling efficiency and accuracy,we utilized 3D laser point cloud data for indoor space modeling.Point cloud data was obtained with a 3D laser scanner and optimized with Autodesk Recap and Revit software to extract geometric information about the indoor environment.Furthermore,we proposed a method for constructing indoor elements based on parametric components.The research outcomes of this paper will offer new methods and tools for indoor space modeling and design.The approach of indoor space modeling based on 3D laser point cloud data and parametric component construction can enhance modeling efficiency and accuracy,providing architects,interior designers,and decorators with a better working platform and design reference.

Blood–brain barrier and laser technology for drug brain delivery

Here,we discuss an important problem in medicine as development of efctive strategies for brain drug delivery.This problem is related to the blood-brain barrier(BBB),which is a“customs”controlling the entrance of different molecules from blood into the brain protecting the normal function of central nervous system(CNS).We show three interfaces of anatomical side of BBB and two functional types of BBB一physical and transporter barriers.Although this protective mechanism is essential for health of CNS,it also creates a hindrance to the entry of drugs into the brain.The BBB was discovered over 100 years ago but till now,there is no efective methods for brain drug delivery.There ane more than 70 approaches for overcoming BBB incuding physical,chenical and biological techniques but all of these tools have limitation to be widely used in clinical practice due to invasi venes,challenge in performing,very costly or lim-itation of drug concentration.Photodynamic therapy(PDT)is usual clinical method of surgical navigation for the resection of brain tumor and anti-cancer therapy.Nowadays,the application of PDT is considered as a potential promising tool for brain drug delivery via opening of BBB.Here,we show the first sucoessful experimental results in this field discussing the adventures and disadv antages of PDT-related BBB disruption as well as altematives to overcome these limitations and possi ble mechanisms with new pathways for brain clearance via gly mphatic and lymphatic systems.

Laser fabrication of functional micro-supercapacitors

Due to the rapid development of portable,wearable and implantable electronics in the fields of mobile communications,biomonitoring,and aerospace or defense,there is an increasing demand for miniaturized and lightweight energy storage devices.Micro-supercapacitors(MSCs)possessing long lifetime,high power density,environment friendliness and safety,have attracted great attention recently.Since the performance of the MSCs is mainly related to the structure of the active electrode,there is a great need to explore the efficient fabricating strategies to deterministically coordinate the structure and functionality of microdevices.Considering that laser technology possesses many superior features of facility,high-precision,low-cost,high-efficiency,shape-adaptability and maneuverability,herein we summarize the development of laser technologies in MSCs manufacturing,along with their strengths and weaknesses.The current achievements and challenges are also highlighted and discussed,aiming to provide a valuable reference for the rational design and manufacture of MSCs in the future.

Superior corrosion resistance-dependent laser energy density in(CoCrFeNi)95Nb5 high entropy alloy coating fabricated by laser cladding

(CoCrFeNi)95Nb5 high entropy alloy(HEA)coatings were successfully fabricated on a substrate of Q235 steel by laser cladding technology.These(CoCrFeNi)95Nb5 HEA coatings possess excellent properties,particularly corrosion resistance,which is clearly superior to that of some typical bulk HEA and common engineering alloys.In order to obtain appropriate laser cladding preparation process parameters,the effects of laser energy density on the microstructure,microhardness,and corrosion resistance of(CoCrFeNi)95Nb5 HEA coating were closely studied.Results showed that as the laser energy density increases,precipitation of the Laves phase in(CoCrFeNi)95Nb5 HEA coating gradually decreases,and diffusion of the Fe element in the substrate intensifies,affecting the integrity of the(CoCrFeNi)95Nb5 HEA.This decreases the microhardness of(CoCrFeNi)95Nb5 HEA coatings.Moreover,the relative content of Cr2O3,Cr(OH)3,and Nb2O5 in the surface passive film of the coating decreases with increasing energy density,causing corrosion resistance to decrease.This study demonstrates the controllability of a high-performance HEA coating using laser cladding technology,which has significance for the laser cladding preparation of other CoCrFeNi-system HEA coatings.

The relation between composition in laser absorption region and ambient pressure

In this paper, the compositions in a laser absorption region can be determined from the experiment of laser impulse coupling. When the ambient pressure varies from 9325 to 33325Pa, the compositions are vapour and plasma; while from 35325 to 101325Pa, they are ambient air and plasma. By analysing the relation between the degree of compression and the ambient pressure, the compositions can be determined and the variation of plasma can be explained.

Slope excavation quality assessment and excavated volume calculation in hydraulic projects based on laser scanning technology

Slope excavation is one of the most crucial steps in the construction of a hydraulic project. Excavation project quality assessment and excavated volume calculation are critical in construction management. The positioning of excavation projects using traditional instruments is inefficient and may cause error. To improve the efficiency and precision of calculation and assessment, three-dimensional laser scanning technology was used for slope excavation quality assessment. An efficient data acquisition, processing, and management workflow was presented in this study. Based on the quality control indices, including the average gradient, slope toe elevation, and overbreak and underbreak,cross-sectional quality assessment and holistic quality assessment methods were proposed to assess the slope excavation quality with laserscanned data. An algorithm was also presented to calculate the excavated volume with laser-scanned data. A field application and a laboratory experiment were carried out to verify the feasibility of these methods for excavation quality assessment and excavated volume calculation. The results show that the quality assessment indices can be obtained rapidly and accurately with design parameters and scanned data, and the results of holistic quality assessment are consistent with those of cross-sectional quality assessment. In addition, the time consumption in excavation quality assessment with the laser scanning technology can be reduced by 70%e90%, as compared with the traditional method. The excavated volume calculated with the scanned data only slightly differs from measured data, demonstrating the applicability of the excavated volume calculation method presented in this study.

Study on Echo Time-Delay Estimation of Pulsed Laser Fuze

Pulse laser range detector is to measure the distance by estimating the time delay between the emitting pulse and echo pulse.In this paper,a mathematical model for the target echo signal of laser fuze has been established;in accordance with this model,the formulas for echo time-delay estimation and for amplitude estimation based on least squares criterion have been deduced.It is argued and simulated that the resolution of echo time-delay estimation could be improved through multi-reference correlation approach.Experiments illustrate that the approach enables pulsed laser fuze to perform high-precision ranging under a low signal-to-noise ratio condition.

New Progress on All Solid State Laser Technology in China

1 Significance of All Solid State Laser (DPL) Technology in Field of LaserBecause of the advantages of high conversion efficiency, good beam quality, small size and light weight, DPL becomes the hotspot and priority of development of laser technology. It may be the main body of laser in the future and replace gas laser and liquid laser. It is a great revolution of laser technology.The developed countries vie in developing DPL. China has achieved great success in this field, but there is a wide gap between the developed countries and us. We should attach great importance to it.

Recent Research and Development Status of Relaxed Optics and Laser Technology: A Review

It is shown that for laser technologies it was necessary to create a new branch of physics: Relaxed Optics (synthesis of methods of the physical optics, quantum electronics, physical chemistry, physics of irreversible phenomena in unitary system). It is allowed to explain complex chain processes of interaction light and matter. Possible applications of Relaxed Optical methods for the modeling of the laser-induced processes phenomena, including laser implantation (surface and subsurface processes), laser-induced optical breakdown (volume processes) and laser annealing of radiation and other defects in solid, are discussed. Perspectives of using these methods for the creation of new laser technologies, including creation new types of optoelectronic devices (heterostructures, diffraction lattices, etc.), resolution the problems of metallurgy, material science, painting, architecture and a building, are analyzed.

Yb-doped passively mode-locked fiber laser with Bi_2Te_3-deposited

In this study we present an all-normal-dispersion Yb-doped fiber laser passively mode-locked with topological insulator（Bi2Te3） saturable absorber. The saturable absorber device is fabricated by depositing Bi2Te3 on a tapered fiber through using pulsed laser deposition（PLD） technology, which can give rise to less non-saturable losses than most of the solution processing methods. Owing to the long interaction length, Bi2Te3 is not exposed to high optical power, which allows the saturable absorber device to work in a high power regime. The modulation depth of this kind of saturable absorber is measured to be 10%. By combining the saturable absorber device with Yb-doped fiber laser, a mode-locked pulse operating at a repetition rate of 19.8 MHz is achieved. The 3-d B spectral width and pulse duration are measured to be 1.245 nm and317 ps, respectively.

Research on wind erosion processes and controlling factors based on wind tunnel test and 3D laser scanning technology

The study of wind erosion processes is of great importance to the prevention and control of soil wind erosion.In this study,three structurally intact soil samples were collected from the steppe of Inner Mongolia Autonomous Region,China and placed in a wind tunnel where they were subjected to six different wind speeds(10,15,17,20,25,and 30 m/s)to simulate wind erosion in the wind tunnel.After each test,the soil surfaces were scanned by a 3D laser scanner to create a high-resolution Digital Elevation Model(DEM),and the changes in wind erosion mass and microtopography were quantified.Based on this,we performed further analysis of wind erosion-controlling factors.The study results showed that the average measurement error between the 3D laser scanning method and weighing method was 6.23%for the three undisturbed soil samples.With increasing wind speed,the microtopography on the undisturbed soil surface first became smooth,and then fine stripes and pits gradually developed.In the initial stage of wind erosion processes,the ability of the soil to resist wind erosion was mainly affected by the soil hardness.In the late stage of wind erosion processes,the degree of soil erosion was mainly affected by soil organic matter and CaCO_(3)content.The results of this study are expected to provide a theoretical basis for soil wind erosion control and promote the application of 3D laser scanners in wind erosion monitoring.

POTENTIAL OF IN VIVO LATENT-TIME ESTIMATION BY LASER AND OPTICAL TECHNIQUES IN CLINICAL AND EXPERIMENTAL DERMATOLOGY

The lag(latency)time(LT)is known in dermatology clinic as an asymptomatic period till the development of skin eruptions.In the laboratory,the LT might determine the interval from"zero"point until the peak(s)of changes in measured laboratory parameter during the performed test.This paper discusses methodological and technical aspects of precise measurement of the LT in the living healthy and pathological skin by laser and optical technologies through clinical and experimental applications in dermatology.Based on a dynamics approach to measure,calculate and interpret the LT in blood and in interstitialfluid compartments of the skin tissue,this method has a potential to promote deeper understanding of the role of complex dynamic processes in the skin at a level of a molecule,and/or an organ in a whole organism.The method of the LT measurement in vivo also promotes new understanding of(patho)physiological,diagnostic and pharmacological aspects of certain dynamic skin lesions and dynamic complex processes that happen in the skin.Utilized laser and optical techniques showed high reliability and objectivity in collecting data from rapidly changed skin lesions and processes,demonstrating the LT measurement as a very easy-to-use calculation procedure with high informativity,which is extremely important for the clinical and laboratory environment.

A Single Mode Hybrid Ⅲ-Ⅴ/Silicon On-Chip Laser Based on Flip-Chip Bonding Technology for Optical Interconnection

A single mode hybrid Ⅲ-Ⅴ/silicon on-chip laser based on the flip-chip bonding technology for on-chip optical interconnection is demonstrated. A single mode Fabry-Perot laser structure with micro-structures on an InP ridge waveguide is designed and fabricated on an InP/AIGaInAs multiple quantum well epitaxial layer structure wafer by using i-line lithography. Then, a silicon waveguide platform including a laser mounting stage is designed and fabricated on a silicon-on-insulator substrate. The single mode laser is flip-chip bonded on the laser mounting stage. The lasing light is butt-coupling to the silicon waveguide. The laser power output from a silicon waveguide is 1.3roW, and the threshold is 37mA at room temperature and continuous wave operation.

Hybrid Laser Technology for Creation of Doped Biomedical Layers

Hybrid laser technologies for deposition of thin films and basic schemes of combination of pulsed laser deposition (PLD) with magnetron sputtering and RF discharges or two lasers or three laser deposition systems are presented. Experiences with deposition of chromium doped diamond-like carbon (DLC) films for coating of prostheses are described. Layers of different chromium concentrations were prepared using hybrid systems (PLD + magnetron sputtering or by double PLD). Results of physical and mechanical characterization of film properties and biomedical tests of trivalent and toxic hexavalent chromium are given. Experiences with double laser deposition of DLC layers doped with silver are also mentioned.

Fabrication of 32 Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective Area Growth Technology

A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13mA. The output power exceeds 10mW at 0V bias when the injection current of the distributed feedback laser is 100mA at 25℃. The side mode suppression ratio is over 50 dB. A 32Gb/s eye diagram is measured with a 3.SVpp nonreturn-to-zero pseudorandom modulation signal at -2.3 V bias. A clearly opening eyediagram with a dynamic extinction ratio of 8.01 dB is obtained.

Laser Technology and Equipment

5W CW Diode-Pumped Solid-State Green Laser；QCW Diode-Pumped Solid-State Green Laser；High Beam Quality Diode-Pumped In-Frared Laser；High Beam Quality Diode-Pumped Infrared Laser；QCW Diode-Pumped Solid-State UV Laser；

The Research Application of 3D Laser Scanning Technology in the Deformation Detection of Large Cylindrical Oil Tank

In order to ensure the safety in using a large cylindrical storage tank,it is necessary to regularly detect its defonnatioii.The traditional total station method has high accuracy in determining the deformation,however,it has a low measxirement efficiency.Long-term observation means,there are more risks in the petrochemical plant,therefore,this paper proposes the usage of the 3D laser scanner,replacing the traditional total station to determine the defbnnation of a large cylindrical storage tank.The Matlab program,is compiled to calculate the point cloud data,while the tank deformation is analyzed from two different points which are,the local concave convex degree and the ovality degree.It is concluded that,the difference between the data obtained by 3D laser scanning,and total station is within the range of oil tank deformation limit,therefore,3D laser scanner can be used for oil tank deformation detection.

Propagation properties of off-axis Hermite-cosh-Gaussian beam combinations through a first-order optical system

Based on the Collins integral formula, the analytic expressions of propagation of the coherent and the incoherent off-axis Hermite-cosh-Gaussian （HChG） beam combinations with rectangular symmetry passing through a paraxial first-order optical system are derived, and corresponding numerical examples are given and analysed. The resulting beam quality is discussed in terms of power in the bucket （PIB）. The study suggests that the resulting beam cannot keep the initial intensity shape during the propagation and the beam quality for coherent mode is not always better than that for incoherent mode. Reviewing the numerical simulations of Gaussian, Hermite-Gaussian （HG） and cosh- Gaussian （ChG） beam combinations indicates that the Hermite polynomial exerts a chief influence on the irradiance profile of composite beam and far field power concentration.