Opto-thermal Moisture Content and Moisture Depth Profile Measurements in Organic Materials

Opto-thermal transient emission radiometry(OTTER) is a infrared remote sensing technique, which has been successfully used in in vivoskin moisture content and skin moisture depth profiling measurements. In present paper, we extend this moisture content measurement capability to analyze the moisture content of fruit(tomato, grape, etc.) skins, and to study the relationship between fruits ripening process and their surface moisture and moisture depth profiles.

Depth Profile Study of Electroless Deposited Sb2S3 Thin Films Using XPS for Photovoltaic Applications

Sb2S3 has gained tremendous research recently for thin film solar cell absorber material because of their easy synthesis, unique electrical and optical properties. The stoichiometry and composition of electroless Sb2S3 thin films were analyzed using XPS depth profile studies. The surface layers were found nearly stoichiometric. On the other hand, the inner layer was rich in antimony composition making it more conductive electrically.

XPS Depth Profile Study of Sprayed Ga2O3 Thin Films

Ga2O3 thin films were fabricated by spray pyrolysis method using gallium acetylacetonate as source material and water as oxidizer. The films were annealed at 450°C for 60 minutes in argon atmosphere. X-ray photoelectron spectroscopy (XPS) depth profile studies were carried out to analyze the stoichiometry and composition of sprayed as-deposited and annealed Ga2O3 thin films. Surface layers and the inner layers of as-deposited and annealed films were found nearly stoichiometric.

Auger Depth Profiling of Carbonized SiC/Si Samples

Silicon carbide (SiC) has been prepared by passing natural gas over (100) oriented hot Si substrate at different temperatures in the range 930~1000℃. Reaction times of 60 and 90 min are used.Depth profile, using Auger Electron Spectroscopy, shows the formation of SiC under a thin coating of carbon for the samples prepared at 930 and 950℃. Annealing, at 1050℃ for 12 h,results in a more pronounced formation of SiC. It is found that at the temperature of 1000℃and reaction times of 60 and 90 min, a hard diamond-like coating is formed.

Depth profiling of arsenian pyrite in Carlin-type ores through wet chemistry

Enrichment of As and Au at the overgrowth rims of arsenian pyrite is a distinctive feature of Carlin-type gold ores.Revealing distribution of such key elements in high resolution is of fundamental importance yet often proves challenging.In this study,repeated non-oxidative acid etching of ore samples from Shuiyindong gold deposit was applied to enable elemental depth profiling of goldbearing arsenian pyrite grains.ICP-OES and AAS were used to determine the dissolved Fe,As,and Au concentrations in each of the etching solutions,and XPS was carried out to exam the etched mineral surfaces.In contrast to conventional ion beam etching that may cause substantial sample damage,our acid etching method does not seem to significantly alter the composition and chemical state of the samples.The etched depths directly converted from the measured elemental concentrations can reproducibly reach a very high resolution of~1 nm,and can be conveniently controlled through varying the etching time.While the Fe and As depth profiles consistently reflect the surface oxidation property of arsenian pyrite,the Au profile displaying an obvious upward trend reveals the ore fluid evolution at the late stage of mineralization.Based on our experimental results,we demonstrate that our wet chemistry method is capable of effective depth profiling of gold ore and perhaps other geological samples,with advantages surpassing many instrumental techniques including negligible sample damage,nanoscale resolution as well as isotropic etching.

DEPTH PROFILING OF DEUTERIUM IN Al_2O_3

D+2 ions of 70 and 90 keV were separately implanted into two thick samples of sintered alumina ceramic and the distribution of deuterium has been measured for three runs at an interval of 5 months using high energy proton backscattering and elastic recoil detection (ERD). The measured data show that there is little diffusion of deuterium in A12O3 and the diffusion coefficient is deduced to be 1.1 ×10-17 cm2/s. The measured total concentration of implanted deuterium is 4.5×1018 at./cm2. The profile of hydrogen adsorbed on the surface of Al2O3 samples was also observed by ERD and 1H(19F, αγ)16O analysis. The distribution range of 1H in Al2O3 after deuterium implantation is much larger than that before one.

Zircon age depth-profiling sheds light on the early Caledonian evolution of the Seve Nappe Complex in west-central J?mtland

The Scandinavian Caledonides comprise nappe stacks of far-travelled allochthons that record closure of the Iapetus Ocean and subsequent continental collision of Baltica and Laurentia.The Seve Nappe Complex(SNC)of the Scandinavian Caledonides includes relics of the outermost Baltoscandian passive margin that were subducted to mantle depths.The earliest of the deep subduction events has been dated to ca.500-480 Ma.Evidence of this event has been reported from the northern exposures of the SNC.Farther south in the central and southern segments of the SNC,(ultra)high-pressure rocks have yielded younger ages in the range of ca.470-440 Ma.This study provides the first record of the early Caledonian event in the southern SNC.The evidence has been obtained by depth profiling of zircon grains that were extracted from the Tv?r?klumparna microdiamond-bearing gneiss.These zircon grains preserve eclogite facies overgrowths that crystallized at 482.6±3.8 Ma.A second,chemically-distinct zircon overgrowth records granulite facies metamorphism at 439.3±3.6 Ma,which corroborates previous geochronological evidence for granulite facies metamorphism at this time.Based on these results,we propose that the entire outer margin of Baltica was subducted in the late Cambrian to early Ordovician,but the record of this event may be almost entirely eradicated in the vast majority of lithologies by pervasive late Ordovician to early Silurian metamorphism.

SIGNAL SAMPLING DEPTH-INDUCED SKEW EFFECT IN SIMS DEPTH PROFILING

The effect of signal sampling depth in SIMS on profile was not reported We have found that the maximum sampling depth in SIMS is considerably bigger than the mean penetration range of primary ions and can skew the profile of secondary ion counts for implanted samples on the more deeper direction from the surface. The effect of maximum sampling depth is true not only for implanted samples but also for the samples in the middle of which there is an other impurity-rich layer. The action principle of signal sampling depth effect and the method of decreasing the error produced by the effect are discussed in this

Methods to Improve the Long Distance Time-Varying Channel Transmission Performance of Expendable Profiler

To improve the transmission performance of XCTD channel, this paper proposes a method to measure directly and fit the channel transmission characteristics by using frequency sweeping method. Sinusoidal signals with a frequency range of 100 Hz to 10 k Hz and an interval of 100 Hz are used to measure transmission characteristics of channels with lengths of 300 m, 800 m, 1300 m, and 1800 m. The correctness of the fitted channel characteristics by transmitting square wave, composite waves of different frequencies, and ASK modulation are verified. The results show that when the frequency of the signal is below 1500 Hz, the channel has very little effect on the signal. The signal compensated for amplitude and phase at the receiver is not as good as the uncompensated signal.Alternatively, when the signal frequency is above 1500 Hz, the channel distorts the signal. The quality of signal compensated for amplitude and phase at receiver is better than that of the uncompensated signal. Thus, we can select the appropriate frequency for XCTD system and the appropriate way to process the received signals. Signals below1500 Hz can be directly used at the receiving end. Signals above 1500 Hz are used after amplitude and phase compensation at the receiving end.

Deciphering non-steady landscape evolution by in-situ cosmogenic nuclide depth profile

In-situ cosmogenic nuclide s are receiving growing attention in surface Earth system science in which the steady-state denudation is an important assumption for estimating the surface denudation of long-lived(103-106 years)surfaces.However,distinguishing steady-state denudation and deciphering a reliable denudation rate from non-steady state denudation region are difficult.Recent depth profile models for investigating the denudation rate,exposure age and inheritance are widely used for sediment and regolith of steady-state denudation region.Here we present in-situ co smogenic nuclides^(10)Be and^(26)Al from two typical granite regolithes from Jixian in Tianjin and Tengchong in Yunnan to model non-steady landscape evolution process by using steady state(Model 1)and non-steady state(Model 2,continuous exposure;Model 3 a,changed denudation rate;Model 3 b,abrupt denudation event)models.The results of steady state model show that both regolithes are in non-steady state.^(10)Be non-steady state models of Jixian regolith reveal that the surface has likely experienced a denudation rate change or an abrupt denudation event during the past several millennia,resulting in a non-steady state.The similar Model 3 a and 3 b denudation rates of 14.6-12.9^(+9.4)and 14.7-14.7^(+9.0)mmkyr^(-1),respectively,might demonstrate the long-term denudation rate rather than the exaggerated rate s of 39.0-2.3^(+2.6)and 39.0-2.4+^(2.5)mm kyr^(-1)calculated by assuming steady-state denudation and ignoring inheritance.The non-steady state model results of Tengchong regolith suggest that the surface has likely experienced a strong denudation about 157 ka(^(10)Be)or 127 ka(^(26)Al)ago.This timing is basically consistent with the termination of the MIS 6(TII:130 ka)and the climate change events in the Tibetan Plateau,suggesting a strong surface landscape denudation during the transition from glacial to interglacial.The compiling of basin-wide denudation rates in the Tibetan Plateau shows a good positive correlation with the regional tectonic activity,indicating that the denudation rate derived from non-steady state region with strong tectonic activity is likely to be overestimated by assuming steady state.We suggest that a combination of steady state and non-steady state depth profile models should be used to quantify denudation rate and exposure age more accurately and effectively in strong tectonic activity or climate change regions.

ION BEAM AND SIMS ANALYSIS ON DAMAGE OF GaAs DOPED WITH N^+

The Rutherford backscattering (RBS) spectra of N+-implanted GaAs are measured with a He+ ion beam of 2.1MeV. The backscattering yield along 【 100 】 aligned incidence increases with the increase in implanted doses. The depth profiles of nitrogen and arsenic are measured by secondary ion mass spectrometer (SIMS).The diffusion of nitrogen in the implanted layers is explained as interstitial migration. The damage is very severe during the ion implantation, and it can be recovered psrtly by annealing. The two-step annealing improves the effect obviously. The calculstion on distribution of damage shows that the recovery is proceeded from the inner side to the surface during the annealing. The mechanism of damage is discussed briefly.

XPS Study of Electroless Deposited Sb2Se3 Thin Films for Solar Cell Absorber Material

As a thin film solar cell absorber material, antimony selenide (Sb2Se3) has become a potential candidate recently because of its unique optical and electrical properties and easy fabrication method. X-ray photoelectron spectroscopy (XPS) was used to determine the stoichiometry and composition of electroless Sb2Se3 thin films using depth profile studies. The surface layers were analyzed nearly stoichiometric. But the abundant amount of antimony makes the inner layer electrically more conductive.

Atomic-Scale AES-EELS Analysis of Structure-Phase State and Growth Mechanism of Layered Nanostructures

A review of our experience in range of electron spectroscopy of the physical vapor-phase deposition and growth of single- and multilayer nanostructures with atomic scale interfaces is presented. The foundation of an innovative methodology for the combined AES-EELS analysis of layered nanostructures is developed. The methodology includes: 1) determination of the composition, thickness, and the mechanism of phase transitions in nanocoatings under the probing depth most appropriated for the range of film thickness 1 - 10 ML;2) quantitative iteration Auger-analysis of the composition, thickness and growth mechanism of nanocoating;3) structural and phase analysis of nanocoatings with use of the analysis of position, shape and energy of the plasmon EELS peak and with subtracting the contribution from the substrate;4) analysis of phase transitions with use of the shift of the plasmon Auger-satellite and 5) non-destructive profiling of the composition of nanocoatings over depth with use of a dependence of the intensity and energy of EELS peaks on the value of the primary electron energy.

Investigation of Sprayed Lu2O3 Thin Films Using XPS

Spray pyrolysis method was used to deposit Lutetium Oxide (Lu2O3) thin films using lutetium (III) chloride as source material and water as oxidizer. Annealing was carried out in argon atmosphere at 450°C for 60 minutes of the films. To investigate the composition and stoichiometry of sprayed as-deposited and annealed Lu2O3 thin films, depth profile studies using X-ray photoelectron spectroscopy (XPS) was done. Nearly stoichiometric was observed for both annealed and as-deposited films in inner and surface layers.

Modeling detector response function of alpha particles for neutron depth profiling

The energy spreading of recorded ions is influenced by straggling,geometrical acceptance angles and detector energy resolution effects in neutron depth profiling(NDP)and a symmetric Gaussian function model was customarily applied before.In addition,the spectra of mono-energetic alpha particles show a well known asymmetric shape as well when measured by silicon detectors.This article presents a physical model predicting the observed energy spectrum of a sample ion with target nuclides in prearranged depths.It is expressed as the convolution of a Gaussian function with a left-hand double-exponential function.Experiment showed that the predicted ions spectrum derived from the asymmetric model matches the observed energy spectrum.Therefore,the model can be applied to produce matrix for inversion of NDP spectrum.

Quantification and visualization of spatial distribution of dendrites in solid polymer electrolytes

Integrating lithium metal anodes with polymer electrolytes is a promising technology for the next generation high-energy-density rechargeable batteries.As the progress is often hindered by the dendrite growth upon cycling,quantifying three-dimensional(3D)microstructures of dendrites in polymer electrolytes is essential to better understanding of dendrite formation for the development of mitigation strategies.Techniques for 3D quantification and visualization of dendrites,especially those with low Li contents,are rather limited.This study reports quantitative measurements of the spatial distribution of Li dendrites grown in solid polymer electrolytes using 3D tomographic neutron depth profiling(NDP)with improved spatial resolution,compositional range,and data presentation.Data reveal heterogeneous distribution of Li over length scales from tens nanometers to centimeters.While most dendrites grow from the plating toward the stripping electrode with dwindling Li quantities,dendrites apparently grown from the Li-stripping electrode are also observed.The discovery is only possibly due to the unique combination of the high specificity and high sensitivity of the neutron activation analysis of Li isotope.

Evaluation of pavement skid resistance using high speed texture measurement

Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth （MPD） or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number （SN40R） collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.

Insights into the deep-tissue photothermal therapy in near-infrared II region based on tumor-targeted MoO2 nanoaggregates

Research on deep-tissue photothermal therapy(PTT)in the near-infrared II(NIR-II,1000–1350 nm)region has bloomed in recent years,owing to higher maximum permissible exposure and deeper tissue penetration over that in the near-infrared I(NIR-I,650–950 nm)region.However,more details need to be uncovered to facilitate a fundamental understanding of NIR-ⅡPTT.Herein,a tumor-targeted therapeutic nanosystem based on NIR-responsive molybdenum oxide(MoO2)nanoaggregates was fabricated.The photothermal conversion capabilities of MoO2 in the NIR-I andⅡregions were investigated step by step,from a simple tissue phantom to a three-dimensional cellular system,and further to a tumor-bearing animal model.NIR-Ⅱlaser exhibited a lower photothermal attenuation coefficient(0.541 at1064 nm)in a tissue phantom compared with its counterpart(0.959 at 808 nm),which allows it to be more capable of deeptissue PTT in vitro and in vivo.Depth profile analysis elucidated a negative correlation between the microstructural collapse of tumor tissue and the penetration depth.Moreover,the depth-related tumor ablation was also studied by Raman fingerprint analysis,which demonstrated the major biochemical compositional disturbances in photothermal ablated tumor tissues,providing fundamental knowledge to NIR-Ⅱdeeptissue photothermal therapy.

Compositional study of δ-NbN film by Auger electron microscopy

The chemical stoichiometry on the surface of superconducting δ-NbN thin films is of great importance for their application.Here,we fabricated the δ-NbN thin films on SiO2/Si substrate by DC sputtering method.The film was characterized using X-ray diffraction(XRD) and atomic force microscopy(AFM).Transport properties were measured to reveal the field dependent superconducting transition temperature.Both XRD and electrical measurement show high crystallinity of δ-NbN phase.A homogeneous and smooth surface morphology was measured by AFM.Auger electron spectroscopy(AES) was applied to analyze the composition along the depth of the film.The evolution of Auger peak profile,heights and nitride stoichiometry at the film surface is discussed.The current study provides a more thorough understanding of complex chemical compositions of δ-NbN thin films.

Deuterium retention in chemically vapor deposited tungsten carbide coatings and hot-rolled tungsten exposed to low-energy deuterium plasma

Samples of chemically vapor deposited(CVD)coatings of tungsten carbides W_(45)C_(55)and W_(60)C_(40)and samples of hot-rolled tungsten were exposed to deuterium(D)plasma at sample temperatures ranging from 323 to 813 K,as a result of which the samples were irradiated with D ions with an energy of about 200 eV per D particle at a flux of D particles of about1.1×10^(21)D·m^(-2)·s^(-1)to a fluence of about 2×10^(24)D·m^(-2).The concentration of deuterium in these samples was examined by the D(3 He,p)4 He nuclear reaction.Based on the measured deuterium depth profiles and assuming that these profiles are determined by diffusing D atoms,the diffusion coefficients of deuterium in the CVD tungsten carbide coatings were determined.Using these diffusion coefficients,an estimate of the Arrhenius relation for the diffusion coefficients of deuterium in CVD tungsten carbide coatings was obtained:D=2.5×10^(-3)exp(-1.12 eV/kT)m~2·s^(-1),where T is temperature expressed in Kelvin,and k is the Boltzmann constant.The concentration of trapped deuterium in the bulk of CVD tungsten carbide coatings is practically independent of the stoichiometry of the coatings.It decreases from about 5×10^(-2)to about 7×10^(-4)D/(W+C)with an increase in the deuterium plasma exposure temperature from 373 to 813 K.The concentration of trapped deuterium in hot-rolled tungsten,expressed in units of the D/W atomic ratio,is more than an order of magnitude lower than the concentration of deuterium in tungsten carbides,and also decreases with increasing plasma exposure temperature.