三维面像数据采集和重建系统

介绍了一种用于口腔医学的基于平面激光的主动三角式三维信息获取和重建系统。通过旋转激光器和ＣＣＤ，可以获得整个物体表面的三维数据，并克服了传统三角法中存在的盲区现象。文中详细介绍了系统的测量原理、校准和重建过程。实验结果表明，系统达到了１ｍ测量范围内０．３ｍｍ的精度。本系统不仅具有较高的测量精度，而且校准和计算过程简单，价格低廉，有较好的应用前景。

双颌外科在矫治牙颌面畸形中的应用

目的对双颌外科术式、手术步骤及术中注意事项进行了讨论总结，为今后从事此项手术提供经验。资料和方法治疗下颌前突综合征３１例，均采用口内途径，上颌ＬｅＦｏｒｔＩ型截骨，下颌升支垂直截骨及颏成形术进行颌骨移动矫治颌骨畸形。结果３１例经双颌外科手术患者均取得良好效果，术后随访有２例术后七年复发，其余２９例效果稳定。结论经口内途径一次完成上下颌骨移动矫治双颌畸形，达到功能和美观的和谐统一，是一种理想术式。通过手术改善畸形容貌，术前对术后面型的准确预测是手术成功的重要条件。

Assessing dynamic modulus properties for typical asphalt mixtures in Jiangsu

To investigate the validity of two dynamic modulus predictive models（ Witczak 1-37 A viscosity-based model and Witczak 1-40 D shear modulus-based model） in the context of Jiangsu, and evaluate the effect of different mixture design variables（ aggregate gradations, binder type, and volumetric properties） on dynamic modulus E＊, asphalt mixtures commonly used in the local surface layer, including Sup-13 and AC-13, are prepared in the laboratory and their dynamic modulus E＊values are predicted based on the above mentioned models. The corresponding asphalt tests, including viscosity and dynamic shear modulus tests, are also carried out to obtain the prediction model parameters. The test results showthat binder type and asphalt content have a significant impact on dynamic modulus.There is a good correlation between the E＊values based on above two predictive models and the measured E＊, while a relatively lower bias can be expected from Witczak 1-37 A model. The test results can be used for the calibration of dynamic modulus with higher accuracy.

轻中度AngleⅢ类错矫治的临床研究

目的通过轻中度安氏Ⅲ错拔牙与非拔牙病例对比颌面软硬组织的变化,探讨两种治疗方案的临界点,以达到最佳治疗效果方法收集青少年轻中度错畸形病例30例,将其随机分为拔牙组和非拔牙组,将两组各15例矫治后的软硬组织投影测量结果进行对比。结果两组的变化量对比只有上前牙轴-FH、下前牙轴-FH、下颌角度有统计学意义。结论提示对轻中度安氏Ⅲ类骨性错,拔牙或非拔牙治疗可能效果差异不大,正畸前期可考虑不拔牙,后期拔牙必须根据X线投影测量及治疗中模型分析预测,面部软组织厚度及侧貌等的影响来综合决定。

Prediction and optimization of process parameter of friction stir welded AA5083-H111 aluminum alloy using response surface methodology

A systematic approach was presented to develop the empirical model for predicting the ultimate tensile strength of AA5083-H111 aluminum alloy which is widely used in ship building industry by incorporating friction stir welding(FSW) process parameters such as tool rotational speed,welding speed,and axial force.FSW was carried out considering three-factor five-level central composite rotatable design with full replications technique.Response surface methodology(RSM) was applied to developing linear regression model for establishing the relationship between the FSW process parameters and ultimate tensile strength.Analysis of variance(ANOVA) technique was used to check the adequacy of the developed model.The FSW process parameters were also optimized using response surface methodology(RSM) to maximize the ultimate tensile strength.The joint welded at a tool rotational speed of 1 000 r/min,a welding speed of 69 mm/min and an axial force of 1.33 t exhibits higher tensile strength compared with other joints.

Surface roughness prediction model in ultrasonic vibration assisted grinding of BK7 optical glass

Pre-knowledge of machined surface roughness is the key to improve whole machining efficiency and meanwhile reduce the expenditure in machining optical glass components.In order to predict the surface roughness in ultrasonic vibration assisted grinding of brittle materials,the surface morphologies of grinding wheel were obtained firstly in the present work,the grinding wheel model was developed and the abrasive trajectories in ultrasonic vibration assisted grinding were also investigated,the theoretical model for surface roughness was developed based on the above analysis.The prediction model was developed by using Gaussian processing regression(GPR)due to the influence of brittle fracture on machined surface roughness.In order to validate both the proposed theoretical and GPR models,32sets of experiments of ultrasonic vibration assisted grinding of BK7optical glass were carried out.Experimental results show that the average relative errors of the theoretical model and GPR prediction model are13.11%and8.12%,respectively.The GPR prediction results can match well with the experimental results.

Analysis and Control of Surface Delamination Defects During Milling of Orthogonal Aramid Fiber‑Reinforced Composites Laminates

The aramid fiber-reinforced composites(AFRC)can increase the durability of corresponding applications such as aerospace,automobile and other large structural parts,due to the improvement in hardness,heat build-up,wear properties and green environmental protection.However,because of its complex multiphase structure and unique heterogeneity and anisotropy,the poor compression fatigue resistance and the incident surface fibrillation are inevitable.To improve the assembly precision of AFRC,mechanical processing is necessary to meet the dimensional accuracy.This paper focuses on the influence of contour milling parameters on delamination defects during milling of AFRC laminates.A series of milling experiments are conducted and two different kinds of delamination defects including tearing delamination and uncut-off delamination are investigated.A computing method and model based on brittle fracture for the two different types of delamination are established.The results can be used for explaining the mechanism and regularity of delamination defects.The control strategy of delamination defects and evaluation method of finished surface integrity are further discussed.The results are meaningful to optimize cutting parameters,and provide a clear understanding of surface defects control.

A new forecast model for the carbon-monoxide concentration in the upper corner of mining face

The CO gas in the upper comer along with the work of mining face in different coal-seam of Lingwu coal-field has deeply affected judgment for the degree of the coal spontaneous combustion and safety work. For this issue, a new calculation and forecast model of the carbon monoxide concentration in the upper comer of mining face was deduced for analyzing and calculating the date from the lab and test-in-place, during this course using the knowledge of heat transfer, fluid dynamics, and mathematics. The model took into account the characteristics of the coal spontaneous combustion, coal mining conditions, and other correlate factors, so the CO concentration of the upper comer safe under the normal condition, and it is in danger when the coal reached spontaneous combustion, which can be calculated accurately with the model and compared with the measured concentration with a tolerance of less than 12%.

Quantitation of HBsAg predicts response to entecavir therapy in HBV genotype C patients

AIM： To analysis the factors that predict the response to entecavir therapy in chronic hepatitis patients with hepatitis B virus （HBV） genotype C. METHODS： Fifty patients [hepatitis B e antigen （HBeAg）- negative：HBeAg-positive = 26：24] with HBV genotype C, who received nalve entecavir therapy for 〉 2 years, were analyzed. Patients who showed HBV DNA levels ≥ 3.0 log viral copies/mL after 2 years of entecavir ther- apy were designated as slow-responders, while those that showed 〈 3.0 log copies/mL were termed rapid- responders. Quantitative hepatitis B surface antigen （HBsAg） levels （qHBsAg） were determined by the Archi- tect HBsAg QT immunoassay. Hepatitis B core-related antigen was detected by enzyme immunoassay. Pre-C and Core promoter mutations were determined using by polymerase chain reaction （PCR）. Drug-resistance muta- tions were detected by the PCR-Invader method. RESULTS： At year 2, HBV DNA levels in all patients in the HBeAg-negative group were 〈 3.0 log copies/mL. In contrast, in the HBeAg-positive group, 41.7% were slow-responders, while 58.3% were rapid-responders. No entecavir-resistant mutants were detected in the slow-responders. When the pretreatment factors were compared between the slow- and rapid-responders; the median qHBsAg in the slow-responders was 4.57 log IU/mL, compared with 3.63 log IU/mL in the rapid- responders （P 〈 0.01）. When the pretreatment factors predictive of HBV DNA-negative status at year 2 in all 50 patients were analyzed, HBeAg-negative status, low HBV DNA levels, and low qHBsAg levels were signifi- cant （P 〈 0.01）. Multivariate analysis revealed that the low qHBsAg level was the most significant predictive factor （P = 0.03）. CONCLUSION： Quantitation of HBsAg could be a use- ful indicator to predict response to entecavir therapy.

Comparative Study of Response Surface Designs with Errors-in-Variables Model

This paper investigates the scaled prediction variances in the errors-in-variables model and compares the performance with those in classic model of response surface designs for three factors.The ordinary least squares estimators of regression coefficients are derived from a second-order response surface model with errors in variables.Three performance criteria are proposed.The first is the difference between the empirical mean of maximum value of scaled prediction variance with errors and the maximum value of scaled prediction variance without errors.The second is the mean squared deviation from the mean of simulated maximum scaled prediction variance with errors.The last performance measure is the mean squared scaled prediction variance change with and without errors.In the simulations,1 000 random samples were performed following three factors with 20 experimental runs for central composite designs and 15 for Box-Behnken design.The independent variables are coded variables in these designs.Comparative results show that for the low level errors in variables,central composite face-centered design is optimal;otherwise,Box-Behnken design has a relatively better performance.

Statistical Downscaling of IPCC Sea Surface Wind and Wind Energy Predictions for U.S. East Coastal Ocean, Gulf of Mexico and Caribbean Sea

A multivariate statistical downscaling method is developed to produce regional, high-resolution, coastal surface wind fields based on the IPCC global model predictions for the U.S. east coastal ocean, the Gulf of Mexico(GOM), and the Caribbean Sea. The statistical relationship is built upon linear regressions between the empirical orthogonal function(EOF) spaces of a cross- calibrated, multi-platform, multi-instrument ocean surface wind velocity dataset(predictand) and the global NCEP wind reanalysis(predictor) over a 10 year period from 2000 to 2009. The statistical relationship is validated before applications and its effectiveness is confirmed by the good agreement between downscaled wind fields based on the NCEP reanalysis and in-situ surface wind measured at 16 National Data Buoy Center(NDBC) buoys in the U.S. east coastal ocean and the GOM during 1992–1999. The predictand-predictor relationship is applied to IPCC GFDL model output(2.0?×2.5?) of downscaled coastal wind at 0.25?×0.25? resolution. The temporal and spatial variability of future predicted wind speeds and wind energy potential over the study region are further quantified. It is shown that wind speed and power would significantly be reduced in the high CO_2 climate scenario offshore of the mid-Atlantic and northeast U.S., with the speed falling to one quarter of its original value.

An investigation of surface deformation after fully mechanized,solid back fill mining

The surface deformation after fully mechanized back filling mining was analyzed.The surface deformation for different backfill materials was predicted by an equivalent mining height model and numerical simulations.The results suggest that:(1) As the elastic modulus,E,of the backfill material increases the surface subsidence decreases.The rate of subsidence decrease drops after E is larger than 5 GPa;(2) Fully mechanized back fill mining technology can effectively control surface deformation.The resulting surface deformation is within the specification grade I,which means surface maintenance is not needed.A site survey showed that the equivalent mining height model is capable of predicting and analyzing surface deformation and that the model is conservative enough for engineering safety.Finally,the significance of establishing a complete error correction system based on error analysis and correction is discussed.

Modeling and prediction of daily gas concentration variation at a mining face based on the elliptic orbit model: A case study

Monitoring and analysis of daily gas concentrations at a mining face is a vital task on safety production and security management in the coal-mining industry. This study addresses modeling and prediction of daily gas concentration variations based on the elliptic orbit model. The model describes the hourly variation in daily gas concentration by mapping its time-series into the polar coordinates to create its elliptic orbit trace for further analysis. Experiments show workability of the proposed method that daily gas concentration variation at a mining face of one coal mine in China is well described by the elliptic orbit model. Result analysis and performance comparison of the proposed elliptic orbit model with the classical AR model on the same prediction tasks indicate potentiality of the proposed elliptic orbit model,which presents a vivid approach for modeling and forecasting daily gas concentration variations in an intuitive and concise way.

Intravascular ultrasound-based analysis of factors affecting minimum lumen area in coronary artery intermediate lesions

Objective To identify clinical characteristics associated with the minimum lumen area （MLA） of proximal or middle intermediate lesions in the left anterior descending （LAD） artery, and to develop a model to predict MLA. Methods We retrospectively analyzed demographic data, medical history, and intravascular ultrasound findings for 90 patients with intermediate lesions in the LAD artery. Linear regression was used to identify factors affecting MLA, and multiple regression was used to develop a model for predicting MLA. Results Age, number of lesions, and diabetes mellitus correlated significantly with MLA of proximal or middle intermediate lesions. A regression model for predicting MLA （mm2） was derived from the data： 7.00 - 0.05 × （age） - 0.50 × （number of lesions）. A cut-off value of 3.1 mm2 was proposed for deciding when to perform percutaneous coronary intervention. Conclusion This model for predicting MLA of proximal or middle intermediate lesions in the LAD artery showed high accuracy, sensitivity, and specificity, indicating good diagnostic potential.

Method of forecasting seismic energy induced by longwall exploitation based on changes in ground subsidence

A method of forecasting total seismic energy induced by longwall exploitation, based on changes in ground subsidence, is presented in the form of a linear regression model with one with one independent variable. In the method, ground subsidence is described with a cross-section area of a subsidence trough Pw along a line of observations in the direction of an advancing longwall front, approximately along the axis of the longwall area. Total seismic energy is determined on the basis of seismic energy data of tremors induced by exploitation. The presentation consists of a detailed method and evaluation of its predictive ability for the area of longwall exploitation within the region of one of the coal mines in the Upper Silesian Coal Basin. This method can be used for forecasting the total seismic energy released by tremors within the area directly connected with the exploitation, in which the seismic activity induced by this exploitation occurs. The estimation of the parameters of the determined model should each time be carried out with investigations of the correctness of the model. The method cannot be applied when the number of recorded phenomena is small and when there is insufficient data to make it possible to calculate the index Pw.

Prediction method for surface finishing of spiral bevel gear tooth based on least square support vector machine

The predictive model of surface roughness of the spiral bevel gear (SBG) tooth based on the least square support vector machine (LSSVM) was proposed.A nonlinear LSSVM model with radial basis function (RBF) kernel was presented and then the experimental setup of PECF system was established.The Taguchi method was introduced to assess the effect of finishing parameters on the gear tooth surface roughness,and the training data was also obtained through experiments.The comparison between the predicted values and the experimental values under the same conditions was carried out.The results show that the predicted values are found to be approximately consistent with the experimental values.The mean absolute percent error (MAPE) is 2.43% for the surface roughness and 2.61% for the applied voltage.

Analysis of the shape of heavy droplets on flat and spherical surface

In this study,a theoretical model was established for predicting the equilibrium shape of the droplet on flat and spherical surfaces.The theoretical equilibrium shape of heavy droplets could be obtained once contact angle and volume of droplets were given.It showed that the predictions of the theoretical flat model were in good agreement with the shape obtained by Surface Evolver when the contact angle is below 120 and the droplet size is on the order of capillary length.This available range will decrease and increase when the heavy droplet is on convex and concave spherical surface,respectively,in contrast to that on flat surface.The available range will decrease more for higher curvature of convex spherical surfaces.

Prediction of recent bank retreat processes at typical sections in the Jingjiang Reach

The Jingjiang Reach is experiencing continuous channel degradation owing to operation of the Three Gorges Project （TGP） in 2003. Significant retreat processes at composite riverbanks have occurred at local sites of this reach, which may influence the stability of the fiver regime and the effect of existing river training works. Therefore, bank retreat plays a key role in fluvial processes of the Jingjiang Reach, and it is necessary to predict the long-term processes of bank retreat at typical sections in the reach. In this study, various factors influencing bank retreat in the Jingjiang Reach are investigated, based on bank erosion processes at four sections and the corresponding flow and sediment conditions. It is discovered that fluvial erosion intensity is a dominant factor in controlling the processes of bank retreat in the reach, although other factors, such as bank soil properties, can also influence bank retreat. The bankfull width at a section with severe bank erosion since 2002 is defined as being equal to the sum of the bankfull width in 2002 and the accumulated bank retreat distance after 2002. The magnitude of the bankfull width can be expressed as an exponential function of the previous 5-year average fluvial erosion intensity during flood seasons. The accumulated distances of bank retreat at four sections over the period 2002-2012 are predicted using the proposed empirical relationships, with the calculated bank retreat processes agreeing well with observed data.

Sensitivity of simulated short-range high-temperature weather to land surface schemes by WRF

The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July,2003 were conducted to examine the sensitivity of simulated surface air temperature(SAT) to different land surface schemes(LSSs) using the Weather Research and Forecasting Model(WRF) Version 2.2 in the short-range mode for 24-h integrations.Initial and boundary conditions employed a National Centers for Environmental Prediction(NCEP) analysis.The results showed that,overall,simulated high-temperature weather is sensitive to different LSSs.Large differences in simulated SAT intensity,threat score,and simulated error under different schemes are identified clearly.In addition,some systematic differences are also in-duced by the LSSs.In terms of threat score from the three LSSs,SLAB is the best,and RUC is better than NOAH.SLAB gives the lowest absolute error for area-averaged SAT,and tends to depict the western Pacific subtropical high with the east-ernmost position at low levels.The LSSs modify the simulated SAT,primarily via the transfer of sensible heat from the land surface to the atmosphere.The physical mechanism of the positive feedback between atmospheric circulation and the SAT is unimportant,with"negative"feedback over most of the simulated areas.This study emphasizes the importance of improving LSSs in SAT forecasting by numerical models.

Development and validation of a model for predicting wheel wear in high-speed trains

In this paper, we present a comprehensive model for the prediction of the evolution of high-speed train wheel profiles due to wear. The model consists of four modules： a multi-body model implemented with the commercial multi-body software SIMPACK to evaluate the dynamic response of the vehicle and track; a local contact model based on Hertzian theory and a novel method, named FaStrip （Sichani et al., 2016）, to calculate the normal and tangential forces, respectively; a wear model proposed by the University of Sheffield （known as the USFD wear function） to estimate the amount of material removed and its distribution along the wheel profile; and a smoothing and updating strategy. A simulation of the wheel wear of the high-speed train CRH3 in service on the Wuhan-Guangzhou railway line was performed. A virtual railway line based on the statistics of the line was used to represent the entire real track. The model was validated using the wheel wear data of the CRH3 operating on the Wuhan- Guangzhou line, monitored by the authors＇ research group. The results of the predictions and measurements were in good agreement.