Analysis of the Stress Distribution Pattern of Anatomic and Non-Anatomic Tooth Forms on Maxillary and Mandibular Edentulous Ridges—A Photoelastic Study

Aim: To compare the type of stress distribution pattern occurring with anatomic and non-anatomic tooth forms beneath a complete denture in both maxillary and mandibular arch. Methodology: A photoelastic model of the edentulous maxillary and mandibular ridge was prepared meticulously to simulate the human mandible and maxilla. Two sets of acrylic teeth with anatomic and non-anatomic occlusal forms were used to fabricate upper and lower dentures. A vertical static load of 100 N was applied through the mandibular model to the maxillary model. After load application on the dentures the photoelastic model as well as the upper and lower complete dentures were sectioned in the midline. The sectioned photoelastic model was viewed through a polariscope to observe the fringe pattern indicating varying amounts of stress distribution. In this study, a two-dimensional photoelastic stress analysis technique was utilized. Results: Force per unit area was observed more in anatomic teeth than the non-anatomic counterpart. Hence anatomic tooth forms may increase the possibility of bone resorption rate over a period of time. However, in non-anatomic lower teeth, a decrease in value was observed from posterior to anterior region. Conclusion: Stress of greater magnitude was observed with cuspal teeth whereas non-anatomic (0°) showed slightly less magnitude of stress. Depending upon the clinical situation the clinician needs to choose the type of occlusal tooth forms for edentulous patients.

A NOTE ON PERTURBATION OF NON-SYMMETRIC DIRICHLET FORMS BY SIGNED SMOOTH MEASURES

This article discusses the perturbation of a non-symmetric Dirichlet form, （ε, D（ε））, by a signed smooth measure u, where u=u1 -u2 with u1 and u2 being smooth measures. It gives a sufficient condition for the perturbed form （ε^u ,D（ε^u）） （for some a0 ≥ 0） to be a coercive closed form.

Finite Element Simulation on the Spin-forming of the 3D Non-axisymmetric Thin-Walled Tubes

The roller movement trace for the 3D non-axisymmetric thin-walled tubes is a complex space curve. Besides the roller rotation caused by contact with the blank, the roller rotates around the workpiece together with the main spindle, and also moves simultaneously along the direction of the revolution radius. The method to correctly establish the finite element （FE） models of the metal spinning is based on the MSC. MARC software was introduced. The calculation formulas considering both the revolution and rotation of the roller were obtained by the mathematical deduction. The saving calculation points m should be a multiple of 4 for one revolution of the roller around the workpiece to obtain the maximum forming force for the spinning of the 3D non-axisymmetric thin-walled tubes. The simulation results conform well to the experimental ones for several spinning methods; the maximum error is less than ±15%.

Non-Synchronous Deformation Effect of Particle in Sheet Metal Forming Process

A new concept referred to the non-synchronous deformation effect of particle in sheet metal forming is proposed. The results of finite element analysis show that the flow resistance of sheet metal can be effectively reduced and thus the forming property can be greatly improved if the moving and deformation state of the neighboring elements with equal perpendicular distance to the entrance contour of die is non-synchronous. Experiment tests are presented and the results agree well with FEA simulation. In addition, the mechanism of the non-synchronous effect is analyzed in detail.

Draping Behavior of Carbon Non-Crimp Fabrics and Its Effects on Mechanical Performance of the Hemispherical Composites

In order to investigate the draping behavior of non-crimp fabrics（NCFs）, two types of carbon NCFs with tricot-chain stitches or chain stitches were formed on a hemispherical mould via a stretch forming process. The shear angle and forming defects of the fabrics were measured on the hemisphere, under different blank holder forces（BHFs）. The results showed that increasing BHF could enhance the shear angle slightly, reduce the asymmetry for the deformation of the fabrics, and change the main type of the process-induced defects. Besides, compression tests were performed on the corresponding composite components. By analyzing the change of fiber volume fraction and structural parameters of the textile reinforcements, the effects of draping behavior of NCFs on the mechanical performance of the composites were studied. The results reveal that draping process has distinguishable impacts on the mechanical properties of the final components, which is closely related to the stitching pattern of the NCFs.

LET SLEEPING DOGS LIE IN THE SLEEPING CAR——TEACHING NON—FINITE V—ING FORM

INTRODUCTION For Chinese students of English,grammar learning is so important that their textbooks inevitably entail grammar sections organized in a linear way.These students treat grammar learning as the stepping stone on their way of English learning.They hope to have a good command of grammar both for their present learning and for their further studies.For their present learning,their linguistic knowledge is tested and assessed through

Non-equilibrium Thermodynamic Analysis of The Transport Properties of Formed-in-Place Zirconium (Ⅳ) Hydrous Oxide-Polyacylate Membranes in aqueous NaNO_3 solution

Nanofiltration of aqueous NaNO3 solution with a dynamically formed Zr(IV) hydrousoxide-PAA membrane is presented. The practical transpoft coefficients Lp, σ, ω were obtainedusing relationships of the non-equilibrium thermodynamics and were used to calculate thefrictional coefficients of a friction model.

A NON－INCREMENTAL TIME－SPACE ALGORITHM FOR NUMERICAL SIMULATION OF FORMING PROCESS

A non-incremental time-space algorithm is proposed for numerical. analysis of forming process with the inclusion of geometrical, material, contact-frictional nonlinearities. Unlike the widely used Newton-Raphson counterpart, the present scheme features an iterative solution procedure on entire time and space domain. Validity and feasibility of foe present scheme are further justiced by the numerical investigation herewith presented.

Non-Local Analysis of Forming Limits of Ductile Material Considering Void Growth

The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.

Zinc chemical forms and organic acid exudation in non-heading Chinese cabbages under zinc stress

As an essential element, zinc also is a heavy metal. Non-heading Chinese cabbage showed obvious tolerance to Zn stress in former research. To further understand the mechanisms involved in Zn adaptability and detoxification, two genotypes Suzhouqing and Aijiaohuang were selected to investigate the chemical forms of Zn and root exudation. Zinc stress obvious strained the plant growth, and Aijiaohuang was more injured than Suhouqing under Zn stress. Under normal Zn levels, the chemical forms of Zn were diverse in three organs between genotypes. Results showed extractions of 2% HAc, 80% ethanol and 1 M NaCl were separately dominant in roots, petioles and leaves. However, under Zn stress (13 mg·L–1 and 52 mg·L–1) most of the Zn was extracted by 1M NaCl, and the subdominant amount of Zn was extracted by 80% ethanol. In the control only four types of organic acid could be detected. While under Zn stress, oxalic acid, tartaric acid, malic acid, lactic acid, acetic acid, citric acid and amber acid were all detected, so it could be speculated Zn detoxification with organic ligands or integrated with pectates and proteins in cells might be responsible for the adaptation of Zn stress in Chinese cabbage.

Heat shock behavior of permanent die during non-solid near-net forming process

Heat shocks caused by alloy melt and coat spraying are the main reason of die plastic deformation and early fracture. Based on theoretical analysis of heat shock phenomenon, two characteristic parameters of die damage caused by heat shock were proposed, which are heat shock plastic deformation index (HSPI) and heat shock crack index (HSCI). The effect of heat shock on die plastic deformation and fracture behaviors was described quantitatively by these two parameters. HSPI represents approaching of heat shock stress to die yield stress. Plastic deformation will happen on a die if this index reaches 1. HSCI represents approaching of heat shock stress to die tensile strength. Die fracture will happen if this index reaches 1. According to theoretical analysis of heat transfer, theoretical models of HSPI and HSCI were established. It is found that, the smaller the interfacial thermal resistance (ITR) is, the higher the pouring temperature and die temperature are before heat shock, and the greater the HSPI and HSCI are, which can be fitted as exponential curves, linear and cubic curves.

Chen’s Inequalities for Submanifolds in (<i>&kgreen;, &#181</i>)-Contact Space Form with a Semi-Symmetric Non-Metric Connection

In this paper, we obtain Chen’s inequalities in (k,?μ)-contact space form with a semi-symmetric non-metric connection. Also we obtain the inequalites for Ricci and K-Ricci curvatures.

Some Methods of Solution of Problems of Sound Diffraction on Bodies of Non-Analytical Form

This review analyzes following numerical methods of a solution of problems of a sound diffraction on ideal and elastic scatterers of a non-analytical form: a method of integral equations, a method of Green’s functions, a method of finite elements, a boundary elements method, a method of Kupradze, a T-matrix method and a method of a geometrical theory of a diffraction.

国外高校非传统型学术的兴起、挑战及其启示

随着博耶多元学术观的提出和大学科研非学术影响力评估的兴起,国外越来越多的高校开始把非传统型学术纳入教师评价体系。然而,这种改变并不意味着高校教师会立即改变其工作模式。在推动非传统型学术纳入教师评价体系的过程中,国外高校遇到了一系列挑战与阻碍,包括学术文化、终身教职与晋升政策、同行评议制度以及教师工作负担等。在深化新时代教育评价改革的背景下,我国高校应考虑将更多类型的非传统型学术纳入教师评价体系。它不仅有助于学界深化对什么是“科研成果”的理解,而且有助于高校教师破除“唯论文”的束缚,还有助于评价教师的“社会贡献”。但是,对其背后的挑战要有充分而清醒的认识。

有机肥配施生物质炭对根际/非根际土壤氮赋存形态的影响

阐明化肥和有机肥配施生物质炭对根际/非根际土壤养分和氮赋存形态的影响,有助于农田氮的高效利用及科学管理。采用盆栽试验方法,设置不施肥(CK)、单施化肥(CF)、施有机肥(M)、化肥配施生物质炭(CFB)、有机肥配施生物质炭(MB)、新鲜有机肥配施生物质炭(FMB)6个处理,通过测定根际及非根际土壤养分含量和土壤氮赋存形态,阐明不同施肥处理对氮形态转化的影响。结果表明:与CK处理相比,MB处理提高非根际及根际土壤pH 0.32和0.28个单位,FMB处理提高根际土壤pH 0.63个单位;MB和FMB处理分别提高根际土壤有机质含量25.4%和84.9%,同时显著提高根际土壤全氮含量25.4%和50.9%,表现出明显的根际效应。施肥能显著提高土壤离子交换态氮(IEF-N)含量,以CF和CFB处理的效果最好。施用有机肥和生物质炭能显著提高土壤碳酸盐结合态氮(CF-N)含量,以M和MB处理效果最好,且CF-N存在根际富集效应。配施生物质炭(CFB、MB和FMB)处理能促进土壤非可转化态氮(NTF-N)向铁锰氧化物结合态氮(IMOF-N)和有机硫化物结合态氮(OSF-N)这两种活性更高的氮形态转化,其中IMOF-N和OSF-N分别占可转化态氮的35.9%~61.7%和26.7%~46.6%,是根际及非根际土壤可转化态氮(TF-N)的主要成分。因此,有机肥配施生物质炭是改善根际及非根际土壤养分和调控氮转化有效的方式。

连接赫尔巴特和杜威:本纳普通科学教学论的考察

如何连接并超越赫尔巴特教育性教学的知识传统和杜威教育性经验的问题探究传统,来重塑德国普通教学论,本纳在其最新的科学教学论中予以了回应。多元的知识形式之间具有一种非等级性的关系,这些多元的知识形式都有其自身独特且关键的方法论;方法处于主体—方法—客体的核心位置;教学过程必须涉及提问、指示、回答三个元素;教学过程通过教育行动敦促学生产生教化行动,并迈向方法能力的掌握和运用(即达到自我活动),也就是说,教学涉及三种因果性:教育因果性、教化因果性和方法因果性;把方法因果性作为教育实践的终点,从而把高阶能力培养内化到教育学理论本身。本纳的科学教学论及其经典性的普通教育学原创性地提出了知识形式的非等级性和分化的实践领域的非等级性,从而捍卫了教育和教学的自身逻辑。

动态照明对疲劳调度员神经行为反应的影响

为探讨利用地铁调度中心照明环境辅助性支持设计来缓解调度员脑力疲劳以实现人机增效的可行性,研究了动态照明对疲劳调度员的影响效应及神经机制。基于实验室环境搭建了可见光谱人工照明实验平台并在此基础上调制了两种环境光照参数(常规照明:500 lx,4 000 K;动态照明:500 lx,4 000~12 000 K),采用单因素两水平被试内设计开展人因照明工效学实验。基于地铁调度任务分析设计了分别表征持续注意、工作记忆和执行控制认知功能的PVT、N-back和MABT-Ⅱ范式,对比分析了16名被试在不同光暴露期间的主观评估、行为绩效和脑电(electroencephalogram,EEG)指标等神经行为反应差异。结果表明,相较于常规照明,疲劳被试在动态照明下的主观感觉更警觉,情绪更积极,其持续注意、工作记忆和执行控制等认知功能得到显著改善。EEG数据揭示这种疲劳干预机制可能来源于动态光线对大脑额叶区α、θ和α-θ等低频频段活动的有效抑制。当前研究初步验证了动态照明对脑力疲劳的影响效应,为城市轨道交通照明设计和疲劳管理提供依据。

吸咐磷后的镧改性秸秆替代化学磷肥施用对土壤磷形态的影响

定向改性材料能提升吸附磷的能力,高效去除水体中磷污染,然而吸附材料的后端利用却鲜有研究和报道。本研究以镧元素改性秸秆用于吸附畜禽养殖尾水中的磷,并将吸附磷后的材料作为磷肥进行小麦盆栽试验,动态取样测定不同形态的磷含量,分析其对土壤中磷形态的影响。结果表明:本研究镧改性秸秆对养殖尾水中磷吸附效率达到98.59%,最佳投加量为1.4 g/L。小麦生长初期,附磷镧改性秸秆继续吸附土壤的活性态磷,促进土壤中活性磷转化为钙吸附态磷,防止土壤磷的流失。随着小麦生长,钙吸附态磷含量逐渐下降,转变为活性态磷持续供应养分,说明附磷镧改性秸秆具备缓释磷肥的属性。本研究为附磷后材料的利用提供了一种新的思路,有助于缓解农业面源污染。

基于Normal Form方法的UPFC多个功能控制器间交互影响分析

统一潮流控制器(UPFC)的重要特点之一就是它具有的多控制功能,包括潮流控制、电压控制和稳定性控制等等。然而时域仿真研究表明统一潮流控制器的多个控制器之间可能存在着较强的交互影响。本文研究了规范型(Normal Form)方法用于分析UPFC控制器间的交互影响问题的可能性,并引入一非线性交互指标定量地指示出控制器间的交互强弱程度。所提方法应用到新英格兰10机39节点系统,并通过时域仿真验证了所提规范型理论分析方法的有效性。

超临界甲烷在矩形通道内传热特性研究

为探究重力对单侧受热情况下矩形再生冷却通道换热性能的影响,采用RNGk-ε湍流模型对超临界压力下甲烷在矩形弯曲管内流动和传热性能进行研究。考察了4种受热情况下重力对内壁面温度、传热系数和热流密度等参数的影响,并引入综合换热评价因子(PEC)着重分析了重力对强化换热能力的作用。结果表明,在直管段重力的存在使管道内形成二次流动,流体间掺混加剧,管道传热性能提升,但在部分弯管段重力使传热性能略微降低;θ=90°时,4种加热工况下传热系数均出现峰值,从无量纲数的分布得知,通道传热能力达到最优,且无重力管道更为显著;通过对比PEC因子,发现重力使再生冷却管道整体换热性能增强,上壁面受热时更为明显。