Alleviation for contact stresses in curvic attachments

This paper studied the contact stresses in curvic attachments.The principal purpose of this research is to employ a method of alleviating the fluctuating hoop stresses which can be considered to be a major contribution to fatigue failure in curvic attachments.This method entails novel precision geometry of the contacting flat on curvic which is a tactic to get appropriate arc heights in in-plane direction as well as vary radius in out-of-plane direction.The dimensional finite elements in both directions were analyzed.These analysis results indicated that significant reduction in fluctuating hoop stresses can be achieved by the proposed method,provided that the precision geometry is controlled sufficiently precisely.

Numerical simulation of constricted and diffusive arc–anode attachments in wall-stabilized transferred argon arcs

A numerical simulation is conducted to investigate arc-anode attachment behavior, especially the formation mechanism of the constricted arc attachment mode for the water-cooled anode of wall-stabilized transferred argon arcs. Argon molecular ions and the corresponding kinetic processes are included to the finite-rate chemistry model in order to capture the chemical nonequilibrium characteristics of the arc near the anode region. Modeling results show that constricted and diffusive arc–anode attachments can be self-consistently obtained at different arc currents while keeping other parameters unchanged. The dominant kinetic processes contributing to ionization and recombination in the arc center and fringes are presented. The results show that in arc fringes and the arc attachment region, molecular ion recombination plays an important role which leads to the rapid loss of electrons. The radial evolution of the production, loss and transport processes of electrons is further analyzed. It is found that for the constricted arc attachment mode, both the recombination and convection transport caused by the anode jet result in the loss of electrons at the arc fringes, which leads to the shrinkage of the arc column at the anode. The formation of the anode jet is due to the combined action of radial and axial Lorentz forces in the anode region.

New Mini Dental Implant Attachments versus O-ring Attachment after Cyclic Aging: Analysis of Retention Strength and Gap Space

Overdenture as a treatment modality for both partially and fully edentulous patients is costeffective and less expensive. The purpose of the present study was to examine the newly fabricated attachments by comparing them with conventional O-ring attachment in vitro in terms of retention force and cyclic aging resistance. A total of 150 samples were prepared and divided into five groups according to the materials used(O-ring attachment, Deflex M10 XR, Deflex Classic SR, Deflex Acrilato FD, and flexible acrylic resin). The retention force of different attachments was measured by a mini dental implant after three subsequent aging(0, 63, and 126) cycles in the circumstances similar to the oral environment. The gap space between the head of the implant and the inner surface of the attachments was detected. Two-way analysis of variance(ANOVA) analysis with multiple comparisons test was applied for statistical analysis. The results showed that Deflex M10 XR had the highest retention force and the lowest gap space after cyclic aging; in addition, by comparing the relative force reduction, the lowest values were obtained in the O-ring attachment and the highest values in the flexible acrylic resin attachment. The retention force measured after cyclic aging for the Deflex M10 XR attachment was greatly improved when compared with the O-ring attachment and other types of attachment materials; in addition, the Deflex M10 XR attachment exhibited the minimum gap space between the inner surface and the mini dental implant head. In conclusion, Deflex M10 XR has the ability to withstand weathering conditions and retains its durable and retentive properties after aging when compared with other attachments.

Ecological Loss & Our Passionate Attachments

The ecological conditions that underlie much of human flourishing still receive scant attention from moral philosophers.While interest in philosophy of ecology has grown in recent years,ethicists are still reluctant to grant ecological issues the status they arguably deserve.These issues are not restricted to custodianship of the natural world;they also pertain to our ability to enjoy love relationships and other passionate attachments.While the connection between human flourishing and love relationships has an ancient provenance,recently philosophers such as Harry Frankfurt,Bernard Williams,and Susan Wolf have emphasised it.Nevertheless,the ecological conditions of our passionate attachments remain obscure.This chapter investigates the extent that passionate attachments are underwritten by a delicate balance of ecological conditions.To do this,the author examines the effects of the pandemic caused by the novel coronavirus,SARS-CoV-2,which has threatened a key aspect of passionate attachments:our sociality.

The characteristics of the spindle fiber attachments(SFAs) enriched fraction from mouse nuclei^1

The characteristics of the particulate mouse centromere enriched fraction from isolated nuclei obtained in our laboratory were investigated by indirect immunofluorescence,test of the activity of microtubule organizing center(MTOC),SDS-PAGE,and fluorescence in situ hybridization.Most of the particles of the fraction are complexes of DNA and kinetochore proteins and show MTOC activity.The DNA isolated from the fraction can hybridize with DNA in the regions of the primary constrictions of all chromosomes of ascions of the primary constrictions of all chromosomes of ascites cells.The kinetochore proteins isolated from the fraction are mainly those with molecular weight of 55 KD and 59 KD.Results suggested that the fraction obtained is a centromere enriched nuclear fraction as indicated in our previous report.

Numerical Study on the Pulsation Characteristics of An Attached Air Bubble Under A Nearby Oscillating Bubble

Numerical simulations of the non-spherical evolution of a pulsating bubble interacting with a stationary air bubble attached to a fixed structure were performed using a three-dimensional boundary integral method by implementing the mirror image method to simplify the processing of the numerical model. Code validation was accomplished by comparing the numerical results with the laboratory experimental data obtained in our previous study. Complex phenomena were observed, including three types of bubble jet forms, which depended strongly on the distance parameter with respect to the initial location of the bubble from the plate, the bubble strength parameter and the initial air bubble radius parameters. The results of the simulations provide detail insight into interesting bubble jetting phenomena,such as bubble splitting, jets moving away from the plate, and bubble shedding. The dimensionless distance parameter and the initial air bubble radius parameter play a major role in determining the shapes of two bubbles and the jetting direction. The air bubble strength parameter did not change the bubble jet direction but influenced the bubble shape.The detachment of the attached air bubble under oscillating bubble suction was easily observed for a small initial air bubble. These results showed that bubble jetting toward the plate was manipulated through the effect of attached air bubble, and that cavitation-based applications and underwater explosion bubble may benefit from this erosion mitigation approach.

Morphology prediction of dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) crystal in different solvent systems using modified attachment energy model

In order to theoretically study the growth morphology of dihydroxylammonium 5,5’-bistetrazole-1,1’-dio late(TKX-50)crystal in different solvent systems,crystal–solvent models were established,and then molecular dynamics(MD)methods were adopted as a means to simulate particle motion.Modified attachment energy(MAE)model was employed to calculate the growth morphology of TKX-50.The simulation results demonstrate that COMPASS force field and RESP charge are suitable for molecular dynamics simulation of TKX-50.The morphologically dominant growth surfaces of TKX-50 in vacuum are(020),(011),(11–1),(100)and(120),respectively.In water(H_(2)O)and N,N-dimethylformamide(DMF)solvents,the(11–1)face is the largest in the habit face,the growth rate of(020)face becomes faster.With the increase of temperature,the aspect ratios of TKX-50 crystal in DMF solvent increase,and the areas of the(120)faces decrease.In ethylene glycol/H_(2)O mixed solvent system with volume ratio of 1/1,aspect ratio of TKX-50 is relatively small.In formic acid/H_(2)O mixed solvents with different volume ratios(1/4,1/3,1/2,1/1 and 2/1),aspect ratio of TKX-50 is relatively small when volume ratio is 1/2.

ONE CASE REPORT OF REHABILITATION OF MIDFACIAL DEFECT USING SEMI-PRECISION ATTACHMENTS

Objective To discuss the application of semi-precision attachment in restoring a midfacial defect, including a nasal, upper lip, and anterior maxillary defect. Methods A splinted metal-ceramic crowns (from the upper right first molar to left molar) and a bar with stud attachments was done. A removable partial denture (RPD) containing the patrix portion of the attachment was then designed to restore the missing maxillary anterior teeth and alveolar ridge. Finally, The facial prosthesis was joined to the denture utilizing two retentive metal posts on the superior aspect of the removable partial. Results A splinted metal-ceramic crowns (from the upper right first molar to left molar) and a bar with stud attachments was done. A RPD containing the patrix portion of the attachment was then designed to restore the missing maxillary anterior teeth and alveolar ridge. Finally, The facial prosthesis was joined to the denture utilizing two retentive metal posts on the superior aspect of the removable partial.The prosthesis markedly improved the appearance of the patient and demonstrated good retention.Conclusion Using attachment in restoring maxillofacial defect may provide adequate retetion which lead to a sucessful treatment outcome.

Relationship between Parent-Child Attachment and Problem Behaviors among Chinese Firstborn Children in Family Transitions: A Meta-Analysis

The implementation of China’s three-child fertility policy has led to a notable increase in multiple-child families.Notably,firstborn children experience a significant transition from being an only child to a non-only child.This transition is associated with problematic behaviors,affecting their social adjustment,sibling relationships,and family harmony.Although several studies have examined the relationship between parent-child attachment and problem behaviors exhibited byfirstborn children during family transitions,thefindings have been inconsistent.Hence,a meta-analytic study was undertaken to elucidate the inconsistencies in this relationship and explore the moderating factors that may contribute to these discrepancies.Using a systematic literature retrieval and screening method,12 effect sizes were derived from the 10 eligible articles,encompassing a sample size of 5319.The meta-analysis demonstrated a low negative association between parent-child secure attachment and problem behaviors exhibited byfirstborn children during family transitions.Furthermore,the present study investigates potential moderator factors,such as children’s age and geographic region,to gain a more nuanced understanding of the relationship.Consequently,the establishment of parent-child attachment relationships has the potential to mitigate problem behaviors observed infirst-born children during family transitions.The implications of thesefindings indicate that parents can nurture secure attachment bonds with their children by demonstrating sensitive responsiveness,employing positive parenting practices,and fostering emotional availability.These efforts contribute to the cultivation of secure internal working models and positive behavioral manifestations withinfirst-born children,which in turn affect their relationships with siblings.

Cytokine changes and embryo attachment in mouse endometrial cells following treated with peripheral blood mononuclear cells(PBMCs)expressing ectopic hCG,and hCG-activated PBMCs

Objective:To compare the effect of human chorionic gonadotropin(hCG)-producing peripheral blood mononuclear cells(PBMCs)and PBMCs activated by hCG in vitro and expressions of related immune genes in mouse implantation.Methods:hCG-producing PBMCs(transfected PBMC)and PBMCs activated by hCG in vitro were introduced into isolated mouse endometrial cells,while cell cultures were divided into four groups:the control,PBMC,transfected,and activated PBMC groups.The expression of studied genes(IL-1β,IL-6,Lif,and Vegf)was evaluated and blastocyst attachment on the cocultured cells(isolated endometrial cells and PBMC cells)was monitored in all four groups.Results:Data showed that expression decreased in the PBMC group compared to the treated PBMC(transfected and activated PBMCs)and increased in transfected PBMC compared to the activated PBMC.Attachment and migration of blastocysts were dramatically enhanced in the transfected PBMC group compared to the activated PBMC group(P<0.05).Conclusions:Use of hCG-producing PBMCs(transfected PBMC)has more influence on endometrial receptivity.

Landscape Upgrading and Transformation of Old Urban Parks from the Perspective of Place Attachment:A Case Study of Nanchang Bayi Park

On the basis of combing the relevant theories of place attachment, the planning framework of upgrading and reconstruction of old parks based on place attachment was put forward. Taking Nanchang Bayi Park as an example, the methods and key points of landscape improvement and transformation of old urban parks based on place attachment were explained to provide new ways and references for the renewal of old urban parks.

The Evolving Bipartite Network and Semi-Bipartite Network Models with Adjustable Scale and Hybrid Attachment Mechanisms

The bipartite graph structure exists in the connections of many objects in the real world, and the evolving modeling is a good method to describe and understand the generation and evolution within various real complex networks. Previous bipartite models were proposed to mostly explain the principle of attachments, and ignored the diverse growth speed of nodes of sets in different bipartite networks. In this paper, we propose an evolving bipartite network model with adjustable node scale and hybrid attachment mechanisms, which uses different probability parameters to control the scale of two disjoint sets of nodes and the preference strength of hybrid attachment respectively. The results show that the degree distribution of single set in the proposed model follows a shifted power-law distribution when parameter r and s are not equal to 0, or exponential distribution when r or s is equal to 0. Furthermore, we extend the previous model to a semi-bipartite network model, which embeds more user association information into the internal network, so that the model is capable of carrying and revealing more deep information of each user in the network. The simulation results of two models are in good agreement with the empirical data, which verifies that the models have a good performance on real networks from the perspective of degree distribution. We believe these two models are valuable for an explanation of the origin and growth of bipartite systems that truly exist.

大学生自杀意念与亲子依恋和同伴依恋及生命意义感的关系

目的:探讨大学生自杀意念与亲子依恋的关系,以及同伴依恋和生命意义感在其中的作用。方法:选取1137名大学生,采用自杀意念量表(PANSI)考察自杀意念、修订版父母同伴依恋量表(IPPA-R)考察亲子依恋和同伴依恋、生命意义量表(MLQ)考察生命意义感。结果:父子依恋、母子依恋、同伴依恋、拥有意义、寻求意义得分与PANSI得分均呈负相关(r=-0.51~-0.19,均P<0.001)。同伴依恋与拥有意义的中介作用及链式中介作用效应值分别是-0.08、-0.16、-0.04,分别占总效应的13.83%、25.83%、6.17%。结论:大学生亲子依恋与自杀意念相关,可以通过提升同伴依恋水平、提高拥有意义感来降低自杀意念。

地方智慧旅游公共服务平台持续使用意愿研究

地方智慧旅游公共服务平台的建设和运营已经成为各地全域旅游建设与发展的重要组成部分,但是平台的持续使用一直是学术和行业界讨论的重点。文章以“游云南”平台为案例,基于刺激-机体-反应理论框架,运用混合研究方法对地方智慧旅游公共服务平台的持续使用意愿进行研究,并提出“因素-感知-使用”地方智慧旅游公共服务平台持续使用意愿综合分析模型,得到如下研究结果。1)在地感知、地方依恋均能够显著提高游客对地方智慧旅游公共服务平台的感知信任和情感依恋,进而提高满意度。其中,平台情感依恋在提高平台持续使用意愿方面具有显著正向作用。具体而言,在地感知会通过信息拓展、形象匹配之机制,地方依恋会通过情感外溢、期待满足之机制促进平台情感依恋和信任的产生,并最终提高持续使用意愿。2)功能集群、享乐体验均能够显著提高游客对地方智慧旅游公共服务平台的感知有用性、感知易用性和感知信任,进而提高游客使用满意度,最终提高持续使用意愿。功能集群通过“信息全面、减少成本”之机制,享乐体验通过“逃离惯常、精美设计”之机制影响游客对平台的积极感知。

附加消能子结构在抗震加固工程中的应用

介绍了消能子结构的研究现状,文中以某小学教学楼抗震加固工程为例,阐述了采用附加消能子结构配合屈曲约束支撑进行抗震加固的设计过程,采用阵型分解反应谱法和时程分析法分析并对比了加固前后结构的抗震性能变化,基于现有研究成果,进行了消能子结构的加固设计和罕遇地震作用下的承载力复核。结果表明:采用附加消能子结构对结构进行抗震加固,在提高建筑抗震性能的同时,可以不影响建筑内部功能。加固后,结构整体刚度增加,自振周期变短,层间剪力增大,整体变形变小,结构的整体受力状态和变形模式得到改善,房屋整体抗震性能提升。罕遇地震作用下,结构整体塑性程度较低,损伤屈服机制更加合理,可以实现“大震不倒”的设防目标。消能子结构为连接消能器和主体结构的关键构件,应重点进行设计,采用柱的N-M曲线进行承载力复核比较便捷。文中设计思路可为类似工程提供借鉴和参考。

超声波钻谐振控制算法设计及试验验证

为解决小天体表面引力小及温差变化大难以实现锚固的问题,提出以超声波钻作为锚固工具并采用模糊控制和恒流控制相结合的策略,实现了低钻压力和高低温环境条件下的超声波钻钻进锚固。压电驱动的超声波钻将高频电能转化为高频机械振动,驱动钻具高频破碎岩石,具有极低钻压力的显著优势,尤其适用于弱引力小天体的钻进锚固作业。针对超声波钻的驱动,对超声波钻的谐振控制算法进行研究。首先,建立超声波钻换能器的等效电路模型,在等效模型基础上研究换能器的阻抗特性、负载特性、温度特性和滞后特性。其次,根据超声波钻的工作特性研究谐振频率识别算法、谐振频率跟踪算法和恒电流控制算法,针对谐振频率跟踪算法研究了基于递归最小二乘估计的频率跟踪算法和基于模糊控制的频率跟踪算法,并对实际控制效果进行对比分析。最后,进行常温常压和高低温环境下钻进试验,试验结果表明,在不同温度环境和不同的钻进对象条件下,所设计的谐振控制算法能够实现对超声波钻的稳定驱动。研究结果表明,所提出的模糊控制和恒流控制能够有效的在低钻压力以及不同温度下实现有效钻进。

高频超声对强直性脊柱炎亚临床附着点炎的筛查评估价值

目的 探讨高频超声对强直性脊柱炎(AS)不同部位亚临床附着点炎早期诊断的价值。方法 选取2017年1月~2023年11月甘肃省人民医院就诊的AS患者100例,依据2022年全球首个附着点炎筛查与评估临床实践指南进行分组:临床附着点炎患者50例(分为有主观症状和无主观症状但有压痛2组);亚临床附着点炎患者50例(无主观症状也无压痛,需借助MRI或超声识别确诊)及50例健康志愿者,分别对其近端足底筋膜、远端跟腱、远端髌韧带、近端髌韧带、远端股四头肌腱和肱三头肌腱附着点行高频超声检查,根据不同部位附着点的厚度、结构、钙化、骨侵蚀、滑囊的厚度及能量多普勒信号,分析超声检查的特异性、敏感度和准确性。结果 受检AS患者超声检查其中有主观症状异常附着点(阳性率为54%),以股四头肌腱附着点为著;无主观症状但有压痛异常附着点(阳性率为46%),以足底筋膜附着点为著;亚临床附着点炎AS患者异常附着点(阳性率为61%),以跟腱附着点为著。高频超声不同亚临床附着点超声检查病变情况显示,与临床检查相较,AS患者亚临床附着点炎的检出率更高(P<0.05);与正常对照组比较,高频超声对亚临床附着点检出率更高,阳性表现以肌腱增厚和滑囊增厚最为常见(P<0.05)。与临床检查比较,高频超声在AS不同部位亚临床附着点早期诊断中,特异性、敏感度、准确性均较高。结论 相较于单一的临床检查,高频超声在AS患者不同部位亚临床附着点早期诊断中,可有效提高检出率,提升诊断价值,弥补了临床检查一直以来对亚临床附着点炎的低估性。

无托槽隐形矫治器扩展上颌牙弓时附件差异对后牙位移的三维有限元分析

目的:利用全牙列精准扫描建模分析无托槽隐形矫治器扩展上颌牙弓时对后牙三维位移的影响。方法:选择2017年1月-2022年6月就诊于笔者医院口腔正畸科的86例成年患者为研究对象。所有患者均为安氏I类错牙合,矫治方案设计为仅通过邻面去釉的方式排齐上下前牙,在全牙列精准扫描建模的基础上,构建无托槽隐形矫治器进行上颌牙弓扩弓前以及扩弓后的后牙三维方向有限元模型的对比。结果:第5组位移量的最大值(3.315 17)与最小值(3.139 25)的比值均为所有组别中最小的。与其他组相比,第5组位移最小值与根尖的距离更近;第5组的第二前磨牙对应得到的等效应力值最小,应力的分布更为均匀。结论:施加附件作用时,对前磨牙的控根效果显著优于磨牙,其中优化后扩弓支持附件对后牙的控根效果更为优秀。

颞下颌关节盘前移位患者盘-髁复合体MRI特征及盘周附着半量化评级研究

目的通过盘-髁复合体磁共振成像(magnetic resonance imaging,MRI)特征分析及盘周附着半量化评级法,探讨颞下颌关节可复性盘前移位(anterior disc displacement with reduction,ADDWR)与不可复性盘前移位(anterior disc displacement without reduction,ADDWoR)中关节盘形态、髁突形态及盘周附着处之间的相关性。材料与方法回顾性分析2021年5月至2022年9月于福建省级机关医院行MRI检查确诊为颞下颌关节盘前移位74例患者共114侧,分为ADDWR组39侧和ADDWoR组75侧,比较关节盘形态Ⅰ~Ⅳ类型、髁突形态3类别及盘周附着处半量化评分分级6级。采用Kruskal-Wallis检验比较两组中不同关节盘形态类型、髁突形态类别及盘周附着分级之间差异。采用Mann-Whitney U检验比较两组之间关节盘形态、髁突形态、盘周附着处总评分及各处附着评分差异。采用Spearman秩相关分析关节盘形态、髁突形态、盘周附着处总评分及各附着与盘-髁复合体可复性与否的相关系数。采用二元logistic回归方法对盘周附着的模型筛选出独立危险因素,作为盘-髁复合体是否可复性的预测。结果除Ⅲ型与Ⅳ型外,两组关节盘形态类型差异均有统计学意义(P<0.05)。两组髁突形态类别差异均有统计学意义(P<0.05)。除1级至4级、5级/6级外,两组盘周附着评分分级差异均有统计学意义(P<0.05)。关节盘可复性与否和关节盘形态、髁突形态及盘周附着处总评分存在较强的正相关性(r分别为0.824,0.626及0.827,P<0.05)。盘周附着处的logistic回归预测模型筛选发现下板附着处是关节盘可复性与否的独立危险因素,回归系数为2.979(OR=19.672,P<0.05)。结论基于盘-髁复合体MRI征象分析及半量化评级法,能有效地评估关节盘可复性与否的相关性因素,为临床治疗提供可靠的影像学参考。

乡村性感知、地方依恋与未来行为意向关系研究——以江西省靖安县三坪村寄宿避暑度假者为例

乡村旅游吸引力的本质在于乡村性,以往研究鲜有以乡村性感知为驱动因素探讨度假者的未来行为意向影响机制。本文选取江西省靖安县三坪村为案例地,开发寄宿避暑度假者乡村性感知、地方依恋与未来行为意向关系测量量表并构建概念模型。实证研究表明:度假者乡村性感知显著正向影响地方依赖、地方认同、未来行为意向;度假者地方依赖显著正向影响地方认同、未来行为意向,地方认同显著正向影响未来行为意向;度假者地方依赖、地方认同在乡村性感知与未来行为意向间均具有显著中介效应,地方依赖与地方认同在度假者乡村性感知和未来行为意向间具有显著链式中介效应。因此,三坪村应关注具身范式旅游体验,精准把控度假者乡村性感知;多维度提升乡村性感知,助力度假者正向行为生成。