Laser Light Scattering Study on Aggregation of Cellulose Diacetate in Acetone

We have investigated the properties of cellulose diacetate in solution by using laser light scattering. The cellulose diacetate molecules can form micelles and micellar clusters in acetone besides the individual chains. As the concentration increases, the average hydrodynamic radius （Rh） linearly increases, whereas the ratio of gyration radius to hydrodynamic radins 〈Rg〉/〈Rh〉 linearly decreases. It indicates that the micelles associate and form micellar clusters due to the intermolecular interactions.

The division and bending of green and red semiconductor laser light at the same time

In this experimental study, the laser light was split and bended using a specially designed glass lenses at the same time. This process has been done at the atmospheric pressure and room temperature conditions. During the experiments, the semiconductor laser as a source of green and red laser diode is used. In addition, polari- zation, magnetic field, electric field or any other auxiliary materials and systems which affect laser light are not used to bend the laser light. Only transparent glass lenses that are designed specially are used in the experimental study.

Roughness Control of Layer-by-Layer and Alternative Spray Films from Congo Red and PAH via Laser Light Irradiation

Films from congo red (CR) alternated with poly(allylamine hydrochloride), PAH, were prepared by layer-by-layer and alternative spray techniques. In order to investigate the change of roughness induced by laser light irradiation (532 nm), both kinds of films were characterized by using UV-visible spectroscopy and atomic force microscopy (AFM). At dif- ferent irradiation times, layer-by-layer, LbL, films showed small changes in the roughness and irregular behavior, whereas spray films exhibited higher and a regular decreasing of roughness with increasing irradiation time. The higher roughness of spray films as compared with the LbL ones was attributed to different formation mechanisms of the films. The decreasing of the roughness as a function of the irradiation time (exhibited by the spray films) was associated to surface relaxation due to the interplay between photoisomerization of congo red dye and the heating of the sample during the laser light irradiation. The results suggested that the alternative spray technique is the best choose to control of roughness of the films by using light irradiation.

Early gastric cancer diagnostic ability of ultrathin endoscope loaded with laser light source

BACKGROUND Conventionally, the low luminous intensity, low image resolution, and difficulty in operation have been reported with the ultrathin endoscope. However, it has markedly advanced recently. The improvement of the diagnostic ability is expected.AIM To compare the early gastric cancer diagnostic ability of an ultrathin endoscope loaded with a laser light source and that of the conventional endoscope.METHODS The target subjects were 375 consecutive patients who underwent endoscopy at our hospital for post-endoscopic submucosal dissection follow-up of gastric cancer from January to August 2018. During endoscopy, the ultrathin endoscope was used in 140 patients(37.3%), and the conventional endoscope was used in235 patients(62.7%). Patient background was adjusted using the propensity score matching method, and gastric cancer detection ability was evaluated in the two groups.RESULTS The gastric cancer detection rate was 7.8% in the ultrathin endoscope group and7.0% in the conventional endoscope group, and the mean intragastric observation time was 4.1 ± 1.7 min in the ultrathin endoscope group and 4.1 ± 1.9 min in the conventional endoscope group, showing no significant differences between the groups. Moreover, the biopsy implementation rate was 31.8% in the ultrathin endoscope group and 41.1% in the conventional endoscope group, and the biopsy prediction rate was 17.9% and 13.2%, respectively, showing no significant differences between the groups.CONCLUSION The gastric cancer diagnostic ability of the ultrathin endoscope loaded with a laser light source was comparable to that of the conventional endoscope. The observation time was also comparable. Thus, endoscopy using the ultrathin endoscope loaded with the laser light source would be the first option in screening examinations of gastric cancer due to its low invasion.

Variable Temperature Laser Light Scattering Microscopy (VTLLSM) Studies on 10-100 μm Size High Purity Gold and Commercial Grade Zinc Grains

The VTLLS microscopy studies were made on high purity gold and commercial grade zinc grains in a temperature range of 30-230?C. Differential area ω and surface activity Sa were estimated from photomicrographs. The ω vs dT/dt (rate of heating) curve was seen to differ from those of silver and titanium. The nature of curve between normalized ω and dT/dt was seen to be non-exponential. The characteristic relation between sectorized differential area ωsec and mean temperature was examined. The present study further establishes the simplicity and versatility of the VTLLS technique, in studying the defect-sub-structure of metal particles such as Au and Zn in presence of an imposed temperature gradient in a reasonable way. As such an attempt was made to connect the ω and defect-sub-structure related parameters.

The Study of Optoacoustic First and Second Sound Waves in Superfluid Helium under the Effect of Gaussian Laser Light Considering Electrostriction Mechanism

The present paper is aimed to study the effect of Gaussian laser light on first and second sound waves in superfluid helium theoretically using optoacoustic method. The mechanism applied in this study is electrostriction mechanism. This study considers crystal parts of superfluid helium with a zero absorption coefficient applying electrostriction mechanism. Affecting Gaussian laser light on these crystal parts, a spectrum of cylindrical first and second sound waves and cylindrical slow and rapid waves is obtained. Meanwhile, frequency of waves amplitudes proportionate to time period of laser light is calculated.

Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting source.Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability.In this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal stability.The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon.Through this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive configuration.In particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

Cyan-green-emitting Ca_(3)Sc_(2)Si_(3)O_(12):Ce^(3+)transparent ceramics:A promising color converter for high-brightness laser lighting

Transparent phosphor ceramics have received increasing attention for high-brightness laser lighting,but commercially available phosphor ceramics are currently mainly limited to yellow YAG:Ce and green LuAG:Ce garnets,leaving a“cyan cavity”which is an obstacle to realizing full-color lighting.Achieving new phosphor ceramics capable of filling the cavity is a challenge.Herein,for the first time,cyan-green-emitting Ca_(3)Sc_(2)Si_(3)O_(12):Ce^(3+)(CSS:Ce)transparent ceramics have been successfully developed by two-step sintering technique under vacuum.The as-prepared CSS:Ce ceramics present high relative density of 99.7%and optical transmittance of 71%in the cyan-green spectral region.It exhibits an efficient band emission peaking at 504 nm(under 450 nm excitation)with internal/external quantum efficiency of 91%/62%.Furthermore,it has excellent thermal stability with a thermal quenching temperature(T_(0.5))of 838 K,approximately 100 K higher than that of LuAG:Ce ceramics(738 K).In addition,the CSS:Ce ceramics can withstand blue laser density of 45.6 W/mm^(2)and meanwhile generates cyan-green light with a forward luminous flux of 813 lm and forward luminous efficacy of 162 lm/W.The CSS:Ce transparent ceramics exhibit excellent luminescence performance comparable to the commercial LuAG:Ce ceramics and could be a highly promising color converter for high-brightness laser lighting.

Laser spot associated high-saturation phosphor-in-glass film for transmissive and reflective high-brightness laser lighting

Phosphor-in-glass(PiG)film is a promising luminescent material in high-brightness laser lighting for its advantages of high efficiency,outstanding color quality,and low-cost preparation,which must bear high laser power(LP)and laser power density(LPD)simultaneously to enable high-luminance light.Herein,laser spot associated high-saturation PiG film was proposed for transmissive and reflective high-brightness laser lighting.Two types of PiG films were prepared by printing and sintering La_(3)Si_(6)N_(11):Ce^(3+)(LSN)phosphor-borosilicate glass pastes on a sapphire substrate(PiG-S)and an AlN substrate(PiG-A),respectively.The PiG films with perfect crystal structure of phosphor were reliably bonded on the substrates.The effects of laser spot areas on the luminescence saturation of LP and LPD were investigated in the PiG films.With the increase of laser spot area from 0.5 to 2.5 mm^(2),the LP threshold of PiG films is gradually raised,while the LPD threshold of PiG films is decreased.The PiG-S withstands a high LP of 23.46 W and a high LPD of 20.64 W/mm^(2),enabling white light with a luminous flux of 3677 lm.The PiG-A withstands a high LP of 41.12 W and a high LPD of 35.56 W/mm^(2),enabling white light with a luminous flux of 2882 lm.Moreover,the PiG-A maintains lower working temperature compared with the PiG-S,and the temperatures reduce with the increasing laser spot area.The results demonstrate that the laser spot associated PiG films realize high saturation thresholds of LP and LPD simultaneously,and enable high luminance for laser lighting.

Ce:GdYAG phosphor-in-glass:An innovative yellow-emitting color converter for solid-state laser lighting

Stable,efficient and high color rendering index all-inorganic color converters are urgently demanded for white laser diodes.Phosphor-in-glass(PiG),possessing the advantages of phosphors excellent quantum efficiency as well as favorable chemical and thermal stability of glass,has attracted widespread attention.There have been only very few reports of Y_(1.31)Ce_(0.09)Gd_(1.6)Al_(5)O_(12)(Ce:GdYAG)PiG for solid-state laser light-ing.Herein,a series of Ce:GdYAG PiG samples are fabricated by a simple solid-state sintering method.Impressively,the supreme internal quantum efficiency of as-prepared PiG is 91%,which is very close to original phosphors(95%).Furthermore,PiG exhibits a high thermal conductivity(1.844 W m^(−1)K^(−1))and a maximum transparency(62%).Remarkably,by changing the concentration of phosphors and the thickness of PiG samples,a luminous efficacy of 163.5 lm/W,high color rendering index of 74.8 and low correlated color temperature of 4806.8 K are achieved under blue laser irradiation.These results indicate that the Ce:GdYAG PiG samples have shown tremendous application foreground as all-inorganic color converter for solid-state laser lighting.

On-chip classification of micro-particles using laser light scattering and machine learning

The rapid detection of microparticles exhibits a broad range of applications in the field of science and technology. The proposed method differentiates and identifies the 2 μm and 5 μm sized particles using a laser light scattering. The detection method is based on measuring forward light scattering from the particles and then classifying the acquired data using support vector machines. The device is composed of a microfluidic chip linked with photosensors and a laser device using optical fiber. Connecting the photosensors and laser device using optical fibers makes the device more diminutive in size and portable. The prepared sample containing microspheres was passed through the channel, and the surrounding photosensors measured the scattered light. The time-domain features were evaluated from the acquired scattered light, and then the SVM classifier was trained to distinguish the particle’s data. The real-time detection of the particles was performed with an overall classification accuracy of 96.06%. The optimum conditions were evaluated to detect the particles with a minimum concentration of 0.2 μg/m L. The developed system is anticipated to be helpful in developing rapid testing devices for detecting pathogens ranging between 2 μm to 10 μm.

R12 hydrate formation kinetics based on laser light scattering technique

A circulating flow system consisting of a transparent U-bend flow loop, a mixing tank and a laser granulometer was set up for studying the kinetics hydrate formation and the pressure is up to 4 MPa. Refrigerant CCl2F2 (R12) hydrate formation experiments were performed using laser light scattering method at 277.1 K and pressures of 0.24 and 0.32 MPa. The liquid flow rates were in the range of 300—1400 L/h. The size distribution and density of R12 hydrate particles in pure water were measured using a laser granulometer. Experimental results show that the size of hydrate particles increases sharply at the initial stage and approaches gradually to a stable size. The hydrate particle concentration in the aqueous phase increases with pressure and circulating liquid flow rate. Based on the material balance, the mathematical model among gas consumption, average hydrate particle size and shading ratio has been established. The calculated results using the mathematical model accord well with the experimental gas consumption data.

Microscope laser light scattering spectroscopy and its applications to non-invasive in situ real time measurements on single intact cells

The principle of the technique of microscope laser light scattering spectroscopy, its development and applications to the studies on single intact cells, including our work on non-invasive in situ real time measurements on single intact erythrocyte simultaneously at the levels of cellular, sub-cellular and intracellular molecules, are introduced.

Progress of laser and light treatments for lower eyelid rejuvenation

Laser and light treatments have recently become popular owing to its efficacy in treating laxity,rhytids,hyperpigmentation of the lower eyelids,and drooping of septum fat.For several decades,our department has explored the application of laser and light treatment for eye rejuvenation.This paper summarizes common treatment methods and analyzes the published literature on the indications and outcomes of multiple laser and light treatments for lower eyelid rejuvenation.An extensive survey of peer-reviewed literature was performed using PubMed,with the search terms“noninvasive treatment”,“infraorbital”,“palpebral bags”,“lower eyelid”,“radiofrequency(RF)”,“laser”,“nonsurgical skin tightening”,and“noninvasive fat reduction”.The results showed that the use of lasers,intense pulsed light(IPL),monopolar RF,bipolar RF,AdipoLASER rejuvenation(ALJ),and fractional RF microneedling are safe and effective treatments for palpebral bags.We conclude that using Qswitched lasers,IPL,RF,ALJ,and fractional RF microneedling is safe and effective for lower eyelid rejuvenation,with minimal complications and quick recovery.Further research and development of optoelectronic therapy may encourage breakthroughs in lower eyelid treatment,such as simplified complex surgery and noninvasive methods.

Ocular damage secondary to lights and lasers: How to avoid and treat if necessary

An armamentarium of the latest light and laser technologies are used by physicians of different disciplines to address a variety of aesthetic challenges in the periocular region and throughout the body. If improperly used, these modalities can inflict serious ocular injury on the patient, support personnel, and operator. It is paramount that providers involved in operating these technologies be knowledgeable about the physical and clinically relevant properties of the unit being used. This involves training in the proper utilization, appropriate treatment parameters, and safety measure for each. Selection of the appropriate eye protection is particularly important for both the patient and the personnel. It is also imperative for the laser operator to understand the range of potential ocular complications associated with the cosmetic use of lasers and lights, to recognize the signs and symptoms associated with ocular damage, and to provide efficient first aid measures should damage ensue. Possible ocular complications related to the cosmetic use of lasers and lights range from mild eyelid swelling and erythema to potentially blinding macular injury. Ocular injury may also be inflicted by the improper selection or placement of eye protection.A complete ophthalmologic evaluation and timely management of potential complications is mandated when there is any concern for ocular injury.

THE THEORY AND APPLICATION OF THE STRUCTURE LIGHT ENGINEERING SURVEYING BASED ON A LASER THEODOLITE WITH THREE FREEDOMS OF ROTATION

The concepts of “confining structure” and structure light are illuminated in this paper.A laser theodolite with three freedoms of rotation,which is aimed at “confining structure”,is developed.Various scanning modes and their mathematical models based on laser theodolite with three freedoms of rotation are discussed.According to the features of a huge object,,the structure light engineering surveying based on laser theodolite with three freedoms of rotation is determined as the main method in an actual application.The observation of four sound concrete posts and forced centering plates.Subsequently,it is transformed into the huge object coordinate system.The scanning mode with plumb plane is selected as the main mode in the whole work.And other assistant methods,such as close range photogrammetry and the method of using reflection sheet,are applied to the work of “scanning dead angle”.At last,a surveying accuracy estimation of this method is done and a surveying accuracy test is finished.It can be concluded that the structure light engineering surveying based on laser theodolite with three freedoms of rotation is considered to be an effective and applied method,and has many superiority to some other surveying methods in the work of surveying “confining structure”.

Diffraction of white-light supercontinuum by femtosecond laser-induced transient grating in carbon bisulfide

Experiments on fs laser-induced transient grating （LITG） in carbon bisulfide （CS2） are carried out to explore the chirp characteristics of a white-light supercontinuum （SC） generated by a 800-nm, 160-fs laser pulse in a 4-mm thick Al2O3 crystal. Two orders of diffraction signals of SC by fs LITG in CS2 are observed, demonstrating that both the third-order process and the fifth-order process are present simultaneously. The experimental results also imply that the formation of an fs transient refractive-index grating in CS2 is mainly due to the electronic polarization process.

Structured Light 3D Vision Based on Laser Scanning Space-encoding and Its Synchro Control

This paper presents the principle and mathematic model for the 3D depth map method based on space encoding images performed by modulating scanning structuredlight according to time sequences,and the synchro control among the camera,laser diode modulation and scanning polyhedron.

Thermal Analysis of Blue Laser Diode for Solid State Lighting Application

Solid-state light sources based on laser diode are becoming great alternative for LEDs. Improvement of the thermal characteristics of InGaN LD is very important for realizing reliable devices. In this investigation the influence of the temperature of diode on light parameters was studied. White light was obtained by coupling blue light of diode with yellow phosphors: YAG:Ce3+ and GYAG:Ce3+ with nitride. For three values of the temperature of LD’s stem, regulated by Peltier module, CCT, CRI and chromaticity coordinates were measured by spectroradiometer. The importance of emission characteristics of materials was shown. Subsequently, the influence of temperature on laser diode intensity was investigated for 120 hours. This experiment was repeated for different levels of current and temperature. Finally, the steady state of thermal finite element analysis was performed to reveal the distribution of the temperature. The analysis showed the importance of heat sink and also temperature control.

Review of laser and light therapy in the treatment of oculofacial pathology

Demand for non-invasive techniques to treat oculofacial pathology has allowed for the growth and development of several new laser and light therapy modalities. These modalities include the use of intense pulsed light(IPL) and photodynamic therapy(PDT), light-emitting diode devices, as well as ablative and non-ablative lasers. Therapeutic applications in the periorbital area may involve the treatment of vascular lesions, telangiectasias, dyspigmentation, photodamage, hypertrichosis, rhytids, and scars. Laser and light-based technology offers patients treatment options that range from conservative to aggressive, allowing for choices between subtle results with little downtime or dramatic results with longer downtime. Advantages of laser treatments, as compared to traditional medical and surgical treatments, include a longer lasting effect than some of the conservative therapies and the ability to serve as a happy medium between non-invasive topical medicine and invasive surgical techniques. For patients seekingnon-invasive alternatives, these modalities confer a major advantage over incisional surgery. Understanding appropriate usage, side effects, and outcomes is before treating functional and cosmetic issues. Here we present a review of current treatment modalities, their use, side effects, and outcomes.