Quantitative measurement of the charge carrier concentration using dielectric force microscopy

The charge carrier concentration profile is a critical factor that determines semiconducting material properties and device performance.Dielectric force microscopy(DFM)has been previously developed to map charge carrier concentrations with nanometer-scale spatial resolution.However,it is challenging to quantitatively obtain the charge carrier concentration,since the dielectric force is also affected by the mobility.Here,we quantitative measured the charge carrier concentration at the saturation mobility regime via the rectification effect-dependent gating ratio of DFM.By measuring a series of n-type GaAs and GaN thin films with mobility in the saturation regime,we confirmed the decreased DFM-measured gating ratio with increasing electron concentration.Combined with numerical simulation to calibrate the tip–sample geometry-induced systematic error,the quantitative correlation between the DFM-measured gating ratio and the electron concentration has been established,where the extracted electron concentration presents high accuracy in the range of 4×10^(16)–1×10^(18)cm^(-3).We expect the quantitative DFM to find broad applications in characterizing the charge carrier transport properties of various semiconducting materials and devices.

Quantitative measurement of hydroxyl radical(OH) concentration in premixed flat flame by combining laser-induced fluorescence and direct absorption spectroscopy

An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.

Quantitative Measurement of the Proportions of High-Order Harmonics for the 4B7B Soft-X-Ray Source at Beijing Synchrotron Radiation Facility

A transmission grating coupled with an X-ray charge coupled device （CCD） is used to quantitatively measure the proportion of high-order harmonics of the soft-X-ray source of beam line 4B7B. The results show that the monochromatic X-ray has third-order and second-order harmonics. The proportion of second-order harmonic of 4B7B is less than 9.0% and the third- order harmonic is below 0.7% when no suppressing method is applied. When suppression methods are used, the proportion of second-order harmonic is less than 1.7% and the third-order harmonic is ignorable.

Numerical analysis of quantitative measurement of hydroxyl radical concentration using laser-induced fluorescence in flame

The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF（laserinduced fluorescence） in flame.The detailed physical models of spectral absorption lineshape broadening,collisional transition and quenching at elevated pressure are built.The fine energy level structure of the OH molecule is illustrated to understand the process with laser-induced fluorescence emission and others in the case without radiation,which include collisional quenching,rotational energy transfer（RET）,and vibrational energy transfer（VET）.Based on these,some numerical results are achieved by simulations in order to evaluate the fluorescence yield at elevated pressure.These results are useful for understanding the real physical processes in OH-LIF technique and finding a way to calibrate the signal for quantitative measurement of OH concentration in a practical combustor.

Big Earth Data for quantitative measurement of community resilience:current challenges,progresses and future directions

Quantitative assessment of community resilience can provide support for hazard mitigation,disaster risk reduction,disaster relief,and long-term sustainable development.Traditional resilience assessment tools are mostly theory-driven and lack empirical validation,which impedes scientific understanding of community resilience and practical decision-making of resilience improvement.In the advent of the Big Data Era,the increasing data availability and advances in computing and modeling techniques offer new opportunities to understand,measure,and promote community resilience.This article provides a comprehensive review of the definitions of community resilience,along with the traditional and emerging data and methods of quantitative resilience measurement.The theoretical bases,modeling principles,advantages,and disadvantages of the methods are discussed.Finally,we point out research avenues to overcome the existing challenges and develop robust methods to measure and promote community resilience.This article establishes guidance for scientists to further advance disaster research and for planners and policymakers to design actionable tools to develop sustainable and resilient communities.

Quantitative measurement of displacement and strain by the numerical moirémethod

The numerical moire method with sensitivity as high as 0.03 nm has been presented. A quantitative displacement and strain analysis program has been proposed by using this method. It is applied to an edge dislocation and a stacking fault in aluminum. The measured strain of edge dislocation is compared with theoretical prediction given by Peierls-Nabarro dislocation model. The displacement of stacking fault is also obtained.

Quantitative measures for assessment of the hydraulic excavator digging efficiency

In this paper,quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed.The following factors are considered:(a) boundary digging forces allowed for by the stability of an excavator,(b) boundary digging forces enabled by the driving mechanisms of the excavator,(c) factors taking into consideration the digging position in the working range of an excavator,and(d) sign and direction of potential digging resistive force.A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising:an undercarriage,a rotational platform and an attachment with boom,stick,and bucket.On the basis of the mathematical model of the excavator,software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator.By using the developed software,the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass(around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms.The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models.

A new method for validation of quantitative measurement by intravascular ultrasound in vivo

Studies in vitro show that intravascular ultrasound (IVUS) underestimates vessel and lumen dimensions. In order to validate IVUS measurement in vivo, we conducted a comparative study during catheterization in fifty patients. The patients underwent IVUS examinations for the purpose of diagnosis or treatment of coronary artery disease. The IVUS system was a 3.5 F, 20 MHz IVUS catheter (Sonicath catheter of Boston Scientific Co.) and a Hewlett Packard console. After examination of the coronary artery, the IVUS probe was withdrawn back into the guiding catheter to measure the average lumen diameter of the guiding catheter (8 F, Cordis). This measurement in vivo (VI) was compared with the true lumen diameter provided by the manufac Department of Cardiology, University of Essen, Essen, Germany (Liu FQ, Ge JB, Baumgart D, Haude M, Caspari G, Grge G, Eick B and Erbel R) turer (MA) and determined by on line quantitative angiography (HICOR, Siemens) (HI). In addition, the IVUS measurement in vitro (VT) was also taken with the same guiding catheter in waterbath at 37℃. The results showed that IVUS underestimated the true lumen diameter by 2.2%±2.6% in vivo, by 3.1%±1.8% in vitro, while HICOR owerestimated the true lumen diameter by 23.0%±6.8%. There was no difference between the IVUS measurements in vivo and in vitro. In summary, IVUS was very accurate for the measurement of a 8 F guiding catheter in vivo with only a minor underestimation, and IVUS measurement was far more reliable than the on line quantitative angiography.

Quantitative and Spatially Resolved Measurement of Atomic Potassium in Combustion Using Diode Laser

A compact optical setup for quantitative and spatially resolved measurement of atomic alkali concentration in combustion is demonstrated. Tunable diode laser absorption spectroscopy and laser-induced fluorescence are combined using a single continuous wave diode laser to measure the line-integration concentration and the relative distribution simultaneously, thereby obtaining the absolute concentration distribution along the laser beam. The results indicate the good performance of this method for one-dimensional quantitative measurement.

Quantitative Analysis of Carbon Content in Bituminous Coal by Laser-Induced Breakdown Spectroscopy Using UV Laser Radiation

The carbon content of bituminous coal samples was analyzed by laser-induced breakdown spectroscopy. The 266 nm laser radiation was utilized for laser ablation and plasma generation in air. The partial least square method and the dominant factor bused PLS method were used to improve the measurement accuracy of the carbon content of coal. The results showed that the PLS model could achieve good measurement accuracy, and the dominant factor based PLS model could further improve the measurement accuracy. The coefficient of determination and the root-mean-square error of prediction of the PLS model were 0.97 and 2.19%, respectively; and those values for the dominant factor based PLS model were 0.99 and 1.51%, respectively. The results demonstrated that the 266 nm wavelength could accurately measure the carbon content of bituminous coal.

Quantitative measurement and application of droplets on physical surfaces based on LIF technology

Contaminated surfaces play a significant role in the transmission of respiratory infectious diseases.To address this issue,we pre-sented a novel quantitative detection method for droplets on physical surfaces,based on the laser-induced fluorescence technique.The proposed detection method was demonstrated in a realistic high-speed train compartment scenario by simulating the process of droplet release during passengers’breathing and coughing.The experimental results showed that this method could offer high precision(10-1 mg/m^(2))for detecting minute substance concentrations,and its ease of operation makes it suitable for complex en-gineering environments.The results also revealed that under the combined effects of the indoor airflow and breathing airflow,the range of droplets released by breathing activity exceeded two rows in front of and behind the release position.Simultaneously,we observed that a large number of droplets settled on the seat surfaces on both sides of the same row as the releaser,with over 36%of these droplets concentrated on the backrest area of the seats.As the respiratory jet velocity increased,the location with the most sed-iment droplets(accounting for 8%of the total sedimentation)occurred on the seat directly in front of the releaser,and approximately 48% of the droplets were found on the back of this seat.Our proposed method overcomes the shortcomings of existing experimental methods in quantitatively capturing the motion characteristics of droplets in complex flow fields.

Quantitative Determination of Composition of Quaternary Cementitious Materials

Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods were developed for quantitative determination of fly ash, slag and limestone powder in fresh cement pastes, mortars and concretes. Limestone powder was determined using thermal analysis method. The residue content of fly ash on an 80um sieve, and silt contents of aggregate were also considered during the quantitative determination of mineral composition of quaternary cementitious system. With the developed methods, the deviations between the measured and the actual mineral contents of the constituent in the eemantitious material in fresh cement paste, mortar and concrete, were within 3%.

Quantitative and qualitative measurement of pear firmness based on near infrared spectroscopy and chemometrics

Firmness is one of the most important characteristics to estimate fruit maturity and quality.The potential of near-infrared(NIR)diffuse reflectance spectroscopy as a nondestructive way for pear firmness evaluation of three varieties(‘Cuiguan’,‘Xueqing’and‘Xizilv’)was studied,both quantitatively and qualitatively.NIR models were established using partial least square(PLS)methods in the spectral range of 800 to 2500 nm.For quantitative analysis,the correlation coefficient r increased with more varieties involved in the model.Best results were obtained in the model for all three varieties:rcalwas 0.934,root mean square error of calibration(RMSEC)and root mean square error of prediction(RMSEP)were 2.06 N and 3.14 N,respectively.For qualitative analysis,the overall accuracies of discriminant PLS models for classifying pears into three firmness levels:low,medium and high firmness level were not so good,percentage of samples correctly classified ranged from 70.63%to 81.25%for calibration and from 56.25%to 74.38%for validation.The results indicate that NIR spectroscopy together with PLS chemometrics method is feasible for quantitative analysis of pear firmness,however,the classification accuracy is too low to put into practical application.

Quantitative measuring and influencing mechanism of urban and rural land intensive use in ChinaQuantitative measuring and influencing mechanism of urban and rural land intensive use in China

Land use issue is an important constraining force to limit economic sustainable development of China. Urban and rural rapid expansion depletes valued land resources under the background of rapid urbanization. An extensive use pattern might cause a serious waste of land resources. The study on influencing mechanism of land intensive use （LIU） in China at the county level is a key tool for effective LIU practice and policy-making. This paper uses OLS model, Spatial Panel Lagged model and Spatial Panel Error model to quantitatively analyze the influencing mechanisms of five class factors and 17 variables supported by GIS （Geographic Information System） and MATLAB. And a comprehensive data set was devel- oped including physical geography and socio-economic information of 2286 counties. Meanwhile, the spatiotemporal pattern of LIU has discussed by means of GIS. The results show that Spatial Panel Data models are slightly superior to OLS model in terms of signifi- cance and confidence level. Regression results of these models indicate that industrialization, urbanization, economic development level, location, transportation and policy have significant impact on LIU of counties. The variables of physical geography are less significant than socio-economic variables. An ignored variable of historical factor, however, became the best significant factor. In the future, the LIU at the county level should take advantage of the new situation by enhancing favorable factors and reducing disadvantageous ones, which can be acquired by improving the entire level and quality of industrialization and urbanization. We argued that an efficient and complete land market and operating system should be built to reflect market-oriented activities at the first place, then, differential LIU regulation policies and measurements should be optimized according to regional differences. In the meantime, we should pay close attention to the carrying capacity of local resources and environments when conducting LIU practices.

Development and Application of an Extraction and Quantitative HPLC Method for Sulforaphene in Radish

Sulforaphene, an isothiocyanate generated by the conversion of glucoraphenin in radish(Raphanus sativus L.), plays an important role in plants as a defensive compound and has been shown to have anti-cancer properties. However, a reliable method for the determination of sulforaphene in radish has not yet been established. In the present study, the enzymolysis conditions, extraction solvent and extraction conditions employed to obtain sulforaphene from radish were all optimized using single factor experiments and orthogonal testing. During these trials, sulforaphene was separated and quantified using reverse phase C18 high performance liquid chromatography(HPLC), employing methanol︰water(3︰7 ν/ν) as the mobile phase at a flow rate of 0.3 mL · min-1 together with a detection wavelength of 245 nm. Evaluation of this newly established method showed good linearity between the sulforaphene concentration and the characteristic peak area over the range of 5 to 200 μg· m L-1(R2 = 0.9996). This method was thus found to be precise. It was established that sulforaphene was extracted from radish with 95.48% efficiency(RSD = 0.94%) using the optimized conditions. This same technique was successfully applied to the quantification of sulforaphene in the fleshy roots of different radish germplasms as a means of selecting the germplasms with the highest sulforaphene levels.

Evolution of wall flow structure and measurement of shear stress issuing from supersonic jet with extended shelf

This paper reports an experimental study on the supersonic jet surface flow structure visualization and shear stress field measurement issuing from a rectangular nozzle with extended shelf. The evolution of the near-field surface flow structures with an increased Nozzle Pressure Ratio(NPR) is successfully captured by the surface oil flow, infrared detection technology, and the Shear-Sensitive Liquid Crystal Coating(SSLCC) technique. Results reveal that under smaller NPR, the wall flow structure is similar to that of a jet without the extended shelf i.e., clean jets,and this is caused by insufficient effect on the boundary layer. However, at higher amplitudes of NPR, there exists a significant effect of the boundary layer, as a near triangular separation forms on the trailing edge of the Mach stem due to the adverse pressure gradient, which is visualized for the very first time in this paper. Furthermore, the vector field of shear stress is measured quantitatively by SSLCC technique. Results shows that the magnitude of shear stress heightened with NPR increasing, and the directions of shear stress changes across the shock wave and expansion fans. In addition, surface streamlines measured by SSLCC is significantly consistent with the streamlines visualized using the oil flow technique.

Effect of lumbar angular motion on central canal diameter： positional MRI study in 491 cases

Background Lumbar spinal stenosis is a common problem that is receiving attention with the advent of novel treatment procedures. Prior positional MRI studies demonstrated lumbar canal diameter changes with flexion and extension. There have not been any studies to examine the amount of spinal canal diameter change relative to the amount of angular motion. The purpose of this study was to evaluate the correlation between the lumbar canal diameter change and the angular motion quantitatively. Methods Positional MRI （pMRI） images for 491 patients, including 310 males and 181 females （16 years-85 years of age）, were obtained with the subjects in sitting flexion 40 degree, upright, and with extension of 10 degrees within a 0.6 T Positional MRI scanner. Quantitative measurements of the canal diameter and segmental angle of each level in the sagittal midline plane were obtained for each position. Then the diameter change and angular motion were examined for correlation during flexion and extension with linear regression analysis. Results The lumbar segmental angles were lordotic in all positions except L1-2 in flexion. The changes of canal diameters were statistically correlated with the segmental angular motions during flexion and extension （P 〈0.001）. The amount of canal diameter change correlated with the amount of angular change and was expressed as a ratio. Conclusions Positional MRI demonstrated the amount of spinal canal diameter change that was statistically correlated with the segmental angular motion of the spine during flexion and extension. These results may be used to predict the extent of canal diameter change when interspinous devices or positional changes are used to treat spinal stenosis and the amount of increased canal space may be predicted with the amount of angular or positional change of the spine. This may correlate with symptomatic relief and allow for improved success in the treatment of spinal stenosis.