3D image system improves the learning curve and contributes to medical education of rhinoplasty

Background: Rhinoplasty is a complex surgical procedure that requires critical analysis and precise design before surgery, making it a challenging operation for both the surgical team and medical educators. This study aimed to evaluate the impact of 3D design involvement on learning curves and to establish a more effective method for rhinoplasty education.Methods: Surgeons who participated in an educational program were divided into two groups. The experimental group was involved in the 3D design before the operation, and the control group was asked to review the rhinoplasty atlas. A self-assessment questionnaire was used to evaluate the learning curve of the eight rhinoplasty procedures for each surgeon, and the overall satisfaction rate data were also collected.Results: The self-assessment scores in both groups showed an increasing trend from the first to the eighth operation. The mean scores of the experimental group were significantly higher than those of the control group at the fifth operation(P=0.01). The satisfaction rate of the experimental group(91.7%) was higher than that of the control group(54.5%).Conclusion: The 3D imaging system can improve the learning curve and satisfaction rate of rhinoplasty education,proving that it is an easy and effective tool for medical education.

Remote sensing image encryption algorithm based on novel hyperchaos and an elliptic curve cryptosystem

Remote sensing images carry crucial ground information,often involving the spatial distribution and spatiotemporal changes of surface elements.To safeguard this sensitive data,image encryption technology is essential.In this paper,a novel Fibonacci sine exponential map is designed,the hyperchaotic performance of which is particularly suitable for image encryption algorithms.An encryption algorithm tailored for handling the multi-band attributes of remote sensing images is proposed.The algorithm combines a three-dimensional synchronized scrambled diffusion operation with chaos to efficiently encrypt multiple images.Moreover,the keys are processed using an elliptic curve cryptosystem,eliminating the need for an additional channel to transmit the keys,thus enhancing security.Experimental results and algorithm analysis demonstrate that the algorithm offers strong security and high efficiency,making it suitable for remote sensing image encryption tasks.

Analysis of 3D curve expansion of conical cam with oscillating tapered roller follower

This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses, we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.

Found Different Attitude Fracture Characteristics of the NMR Curve by Application of 3D Printing Samples

Nuclear magnetic resonance (NMR) has many advantages, such as little testing time, no harm to rock specimen, and is widely used in the measurement of reservoir pore structure. 3D printing also has many advantages, such as repeating the printing the same attributes samples, forming sample by known rock pore structure, adding different pores or fractures to sample. For the study of fractured reservoir provides a new train of thought by combining NMR and 3D printing. Nuclear magnetic core analysis is an important work in the study of core, using a T2 spectrum at a certain echo time can also be found in the core fractures. The study, by CT scans to establish reservoir pore structure, based on the basic of adding different attitude fracture forming four fracture characteristics of rock sample, using 3D printing for solid sample, through the analysis of the nuclear magnetic resonance (NMR) of these sample, get the response characteristics of fracture characteristics on the T2 curve, the quantitative calculation of fracture porosity of rock sample, the result accord with to establish the model of fracture porosity is very good. For the study of fractured oil and gas reservoir development the new field.

3D Target Localization Based on FrFT from Spaceborne Curve SAR

Synthetic aperture radar(SAR)three-dimensional(3D)imaging technology can reconstruct the complete structure of observed targets and has been a hot topic.Compared with tomographic SAR,array interferometric SAR,and circular SAR,curve SAR can use less data to achieve 3D positioning of targets.Most existing algorithms for estimating Doppler frequency modulation(FM)rate are based on sub aperture partitioning,resulting in low computational efficiency.To address this,this article establishes a target height estimation model,which reflects the relation-ship between the height and the residual Doppler FM rate for spaceborne curve SAR.Then,a fast SAR 3D localization processing flow based on fractional Fourier transform(FrFT)is proposed.Experimental verification demonstrates that this method can estimate the Doppler FM of the target column by column,and the 3D position error for non-overlapping targets is controlled within 1 m.For overlapping points with an intensity ratio greater than 1.5,the root mean square error(RMSE)of the estimation results is around 5 m.If the separation between overlapping points is greater than 35 m,the RMSE decreases to approximately 2 m.

3D reconstruction of complex curved objects from line drawings

An active research topic in computer vision and graphics is developing algorithms that can reconstruct the 3D surface of curved objects from line drawings. There are a number of algorithms have been dedicated to solve this problem, but they can＇t solve this problem when the geometric structure of a curved object becomes complex. This paper proposes a novel approach to reconstructing a complex curved 3D object from single 2D line drawings. Our approach has three steps： （1） decomposing a complex line drawing into several simpler line drawings and transforming them into polyhedron; （2） reconstructing the 3D wireframe of curved object from these simpler line drawings and generating the curved faces; （3） combining the 3D objects into the complete objects. A number of examples are given to demonstrate the ability of our approach to successfully perform reconstruction of curved objects which are more complex than previous methods.

Efficient single-pixel imaging encrypted transmission based on 3D Arnold transformation

Single-pixel imaging(SPI)can transform 2D or 3D image data into 1D light signals,which offers promising prospects for image compression and transmission.However,during data communication these light signals in public channels will easily draw the attention of eavesdroppers.Here,we introduce an efficient encryption method for SPI data transmission that uses the 3D Arnold transformation to directly disrupt 1D single-pixel light signals and utilizes the elliptic curve encryption algorithm for key transmission.This encryption scheme immediately employs Hadamard patterns to illuminate the scene and then utilizes the 3D Arnold transformation to permutate the 1D light signal of single-pixel detection.Then the transformation parameters serve as the secret key,while the security of key exchange is guaranteed by an elliptic curve-based key exchange mechanism.Compared with existing encryption schemes,both computer simulations and optical experiments have been conducted to demonstrate that the proposed technique not only enhances the security of encryption but also eliminates the need for complicated pattern scrambling rules.Additionally,this approach solves the problem of secure key transmission,thus ensuring the security of information and the quality of the decrypted images.

An optimal on-site calibration method in measurement system of dynamic envelope curve of high-speed vehicle

High-speed vehicle dynamic envelope curve is defined as the maximum limit outline affected by a variety of adverse factors while the train is running. Considering the difficulties in the current measurement system such as complicated calibration process,cumbersome aided-instruments,strict limitation of working distance, this paper carries out an optical method in which two high-speed cameras with variable-zoom lenses are adopted as binocular stereo sensors of measurement system and a high-ac-curacy 3D target with fast reconstruction is designed. The intrinsic parameters of the sensors and the relative positions between coordinate systems are solved by the method of colinearity constrained optimization algorithm. The calibration process is easy to operate and the device is also of portability. Most importantly, the severe working distance limitation between sensors and measured body is solved, enhancing the adaptability of measurement system to environment. Experimental results show that when the sensors are in the range of 8 -16 m away from the measured body, system accuracy can reach up to ±0. 5 mm, which meets the requirements to measure the dynamic envelope curve of high-speed vehicle.

Exploring the Potential to Uniquely Manufacture Curved VARTM Epoxy Composites Using Cost-Effective FDM Molds

The Resin Infusion or the VARTM (Vacuum Assisted Resin Transfer Molding) process has significant potential to be used to manufacture curved composites. Another way to produce curved or complex geometry is to use 3D printers. 3D or FDM (Fused Deposition Modelling) printers are now being used to produce relatively cheaper curved parts using thermoplastics such as PLA. However, the strength and mechanical performance of these parts is limited and can be enhanced if the polymer is reinforced with a type of fiber for instance. Research is being carried out to produce fiber rein-forced thermoplastic composites but that process is expected to be more expensive than the alternative methods such as injection or compression molding. Furthermore, to understand the manufacture of a hybrid composite using thermoplastics, fibers and epoxy resin, research and investigation need to be carried out. In this research, there are single-sided, double-sided, reusable, disposable and consumable molds. Most of the molds were created either using an FDM printer or manually. These molds were then used to manufacture flat and curved composite structures via the resin injection process, i.e. VARTM with epoxy resin system and glass/carbon/flax fiber reinforcement. By replacing the costly metallic molds by significantly cheaper molds, the cost of production was expected to further reduce. Furthermore, using double-sided PLA molds was not expected to be a threat to the overall cost of the composite part in question compared to double-sided matched molds used in compression molding. Shear strength, tensile strength and charpy impact strength of most of the manufactured composite parts were also investigated. The strengths were compared based on the method of mold usage. The results showed that this method is effective for a cheaper production of curved epoxy resin composites. However, the strength of the part will decrease as the curved profile gets more complicated unless the basic resin infusion process is altered.

The Layout and Simulation of Logarithmic Spiral Double Curved Arch Dam Transverse Joints

Because of its good condition with mechanics, logarithmic spiral double curve arch bam has been widely used in the practical engineering. The introduction of a new method in how to divide transverse joint in arch dam will be given and the further research of its calculation has been done. The C＋＋ is used in electronic procedure and the 3D simulation has been finished with AutoCAD, which will provide the object model for computer simulation of the arch dam and the division of finite element mesh. Meanwhile, this method in dividing the transverse joint in arch dam also can be taken as the calculated basis for the design and calculation of arch dam, construction lofting and the calculation of the work amount.

3维Douglas-Peucker算法及其在DEM自动综合中的应用研究

在分析2维Douglas-Peucker算法原理实质的基础上,提出3维Douglas-Peucker算法,并将此法应用到对DEM的基础———3维离散点的自动综合上。采用计算机程序对新算法进行的验证,初步结果表明该算法能较好地筛选出DEM整体及局部范围的地貌特征点,其计算效率也较令人满意。

血浆(1,3)-β-D葡聚糖检测诊断侵袭性真菌感染的价值

目的探讨血浆(1,3)-β-D葡聚糖检测在侵袭性真菌感染(IFI)的诊断价值。方法我院2009年1-12月对怀疑有真菌感染的147例患儿,应用MB-80微生物动态快速检测系统检测其血浆(1,3)-β-D葡聚糖的含量,比较IFI组与非IFI组血浆(1,3)-β-D葡聚糖水平,应用ROC曲线确定最佳临界值。结果 147例患儿中IFI组32例,非IFI组115例;IFI组血浆(1,3)-β-D葡聚糖水平明显高于非IFI组(P<0.01);血浆(1,3)-β-D葡聚糖试验阳性率(32.7%)高于真菌培养法(5.9%)(x^2=14.85,P<0.01);血浆(1,3)-β-D葡聚糖试验检测IFI组的ROC曲线下面积0.863,大于真菌培养法;使用最佳临界值16.7pg/mL诊断IFI的灵敏度(84.4%)和特异度(81.7%)最高。结论血浆(1,3)-β-D葡聚糖试验可用于临床诊断IFI,应结合其他微生物诊断方法,才能获得及时准确的诊断,从而提高IFI的治愈率,改善患者预后。

3D-C／SiC复合材料的高温疲劳性能

采用应力比为0.1和0.5,频率为60和20Hz的正弦波从室温至1500℃,在10-4Pa真空中对3D-C/SiC复合材料进行拉—拉疲劳实验;获得其在应力比0.1频率60Hz条件下室温、1100、1300和1500℃的疲劳曲线,以及应力比0.1频率20Hz和应力比0.5频率20Hz条件下1500℃的疲劳曲线。结果表明,若取循环基数为106周,应力比0.1频率60Hz条件下,3D-C/SiC复合材料在室温、1100、1300和1500℃的疲劳极限分别为235、350、285和240MPa,约为其拉伸强度的87%、97%、94%和90%;疲劳极限与比例极限和拉伸强度随温度有相似的变化规律,即随温度升高而增加,在1100℃达到最大值,尔后随温度增加而下降;但是S—Nf曲线的斜率的变化规律恰好与此相反。应力比的增加和频率的降低,均使复合材料1500℃的疲劳极限有所减小。

血清(1,3)-β-D-葡聚糖检测对深部真菌病诊断的研究

目的探讨血清（1,3）-β-D-葡聚糖对深部真菌病的诊断价值。方法将2014年2~6月天津市武警后勤学院附属医院110份数据（标本140份）分为侵袭性真菌病患者组33例和无侵袭性真菌病组77例,分析比较葡聚糖水平,并使用ROC曲线确定最佳临界值。结果侵袭性真菌病患者组的葡聚糖水平（279.78±83.26）pg/m L,明显高于对照组（34.05±9.35）pg/m L（P〈0.001）;ROC曲线下面积为0.946（95%的置信区间为0.904~0.988）,当以95.20 pg/m L为临界值时,实验的敏感度、特异度、阳性预测值和阴性预测值分别为84.8%、93.5%、80.0%和93.3%;临床符合率达到89.1%。Kappa值0.784（P〈0.05）。结论血清葡聚糖水平可以用于深部真菌感染的诊断,本研究中用北京金山川公司的GKT-1M Set动态真菌检测试剂盒检测血清葡聚糖水平,进行深部真菌感染诊断时的最佳临界值为95.20 pg/m L,当以此临界值对深部真菌感染进行诊断时,临床一致性较好。

基于LADRC的3D舞台威亚协调同步控制方法

针对机电参数摄动、钢绳弹性延伸及负载变化等对3D威亚系统造成的影响,根据"抗扰范式"建模理念,提出了一种基于线性自抗扰控制(LADRC)的3D舞台威亚协调同步控制策略,分别对3D舞台威亚系统的控制结构、控制器设计以及协调同步算法进行了研究.首先从威亚系统的单机LADRC设计入手,并进行相关稳定性分析;然后融合并联硬同步方法设计了适宜的软协调算法,进而实现了3D威亚系统的协调同步运行.仿真结果表明,所提出的控制策略,对于舞台空间内预设的无论是常规或非常规复杂姿态曲线,即使存在内外部不确定性"总扰",均能使3D威亚有着良好的轨迹拟合效果及协调同步性能,尤其是软协调同步算法中离线与在线的结合,为3D舞台威亚的工程应用提供了实施便利.

Tensile Properties of 3-Dimension-4-directional Braided C_f/Si C Composite based on Double-scale Model

The longitude tensile properties of 3-Dimension-4-directional（3D-4d） braided C/Si C composites（CMCs） were investigated with the help of a double scale model. This model involves micro-scale and unit-cell scale. In micro-scale, the tensile properties of fiber tows which involves matrix cracking, interfacial debonding, and fiber failure are studied. The unit-cell scale model can reflect the braided structure and simulate the tensile properties of 3D-4d CMCs by introducing the tensile properties of fiber tows into it. Quasi-static tensile tests of 3D-4d braided CMCs were performed on a PWS-100 test system. The predicted tensile stressstrain curve by the double scale model is in good agreement with that of the experimental results.

血清CTRP-3和D-D水平与高血压脑出血术后转归的相关性研究

目的研究血清补体C1q/肿瘤坏死因子相关蛋白-3(CTRP-3)和D-二聚体(D-D)水平与高血压脑出血(HICH)术后转归的相关性。方法纳入2016年2月—2019年2月132例HICH患者(观察组)和86例健康志愿者(对照组)的临床资料。对比2组的血清CTRP-3、D-D水平,观察组进行术前、术后1 d和5 d的血清CTRP-3及D-D水平测定,以及术后1个月的格拉斯哥预后评分(GOS)评估。比较预后良好和预后不良HICH患者血清CTRP-3、D-D水平,分析术后5 d血清CTRP-3、D-D水平与患者预后的相关性,以及对HICH患者预后不良的诊断价值。结果观察组术前血清CTRP-3水平低于对照组,血清D-D水平高于对照组(P<0.01)。预后良好HICH患者术后1、5 d的血清CTRP-3水平高于预后不良HICH患者,血清D-D水平低于预后不良HICH患者(P<0.01)。HICH患者术后5 d血清CTRP-3水平与GOS评分呈明显正相关性(r=0.612,P<0.05),而血清D-D水平与GOS评分呈明显负相关性(r=-0.673,P<0.05)。血清CTRP-3诊断HICH患者术后预后不良的灵敏度为87.50%,特异度为76.50%,最大约登指数为0.64;血清D-D诊断HICH患者术后预后不良的灵敏度为85.94%,特异度为92.65%,最大约登指数为0.79。结论术后5 d的血清CTRP-3和D-D水平可与HICH术后转归存在相关性,具有一定临床诊断价值。

A methodology for damage evaluation of underground tunnels subjected to static loading using numerical modeling

We have proposed a methodology to assess the robustness of underground tunnels against potential failure.This involves developing vulnerability functions for various qualities of rock mass and static loading intensities.To account for these variations,we utilized a Monte Carlo Simulation(MCS)technique coupled with the finite difference code FLAC^(3D),to conduct two thousand seven hundred numerical simulations of a horseshoe tunnel located within a rock mass with different geological strength index system(GSIs)and subjected to different states of static loading.To quantify the severity of damage within the rock mass,we selected one stress-based(brittle shear ratio(BSR))and one strain-based failure criterion(plastic damage index(PDI)).Based on these criteria,we then developed fragility curves.Additionally,we used mathematical approximation techniques to produce vulnerability functions that relate the probabilities of various damage states to loading intensities for different quality classes of blocky rock mass.The results indicated that the fragility curves we obtained could accurately depict the evolution of the inner and outer shell damage around the tunnel.Therefore,we have provided engineers with a tool that can predict levels of damages associated with different failure mechanisms based on variations in rock mass quality and in situ stress state.Our method is a numerically developed,multi-variate approach that can aid engineers in making informed decisions about the robustness of underground tunnels.

Slicing and support structure generation for 3D printing directly on B-rep models

Traditional 3D printing is based on stereolithography or standard tessellation language models,which contain many redundant data and have low precision.This paper proposes a slicing and support structure generation algorithm for 3D printing directly on boundary representation(B-rep)models.First,surface slicing is performed by efficiently computing the intersection curves between the faces of the B-rep models and each slicing plane.Then,the normals of the B-rep models are used to detect where the support structures should be located and the support structures are generated.Experimental results show the efficiency and stability of our algorithm.

An Overview of Modeling Yarn’s 3D Geometric Configuration

Modeling the 3D geometric configuration of yarn is the base of building the 3D fabric structure. The surfaces of the yarns are modeled by many facets. To improve the efficiency of modeling, 3D yarn is usually designed by Bezier curve, spline curve or B-spline curve on the principle of Computer Graphics. The paper reviews different 3D modeling methods for single yarn from the view of cross-section and central line. Some improvements for a better visual effect such as inserting twist and hairiness are illustrated as well. Based on the single yarn, the folded yarn and some fancy yarns can also be modeled in 3D space as long as the cross-sections of the control sections of the component single yarn are determined. Applications of the various 3D yarns are demonstrated. The advantages and the drawbacks of various methods are explained and compared as well. Comparatively speaking, modeling technology based on spline curve is more convenient and flexible, perhaps it is the most popular tool since it is capable of designing different kinds of yarns mentioned above and gets the maximum support from the different developing platforms such as OpenGL, 3DS-MAX, Solid Works CAD, etc.