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下颌中切牙种植单端固定桥桥体接触面对种植体及其周围组织应力影响的三维有限元分析
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作者 何雨桐 马春丽 +5 位作者 乔庚 刘佳怡 王媛 宋君 刘毅 汪振华 《中华口腔医学杂志》 CAS CSCD 北大核心 2019年第7期463-468,共6页
目的比较下颌中切牙种植单端固定桥桥体与邻牙接触面形状对种植体、骨组织应力分布及修复体位移的影响。方法采用CT扫描获取健康成人下颌骨及牙列影像数据,建立下颌中切牙种植体单端固定桥修复的三维有限元模型,其中与桥体接触的邻近天... 目的比较下颌中切牙种植单端固定桥桥体与邻牙接触面形状对种植体、骨组织应力分布及修复体位移的影响。方法采用CT扫描获取健康成人下颌骨及牙列影像数据,建立下颌中切牙种植体单端固定桥修复的三维有限元模型,其中与桥体接触的邻近天然牙的接触面分别设计为椭圆形和梯形(唇侧底边略小而舌侧底边略大)。在桥体41长轴中线切缘处加载120 N载荷,方向分别设定为平行于牙体长轴且向下的0°角,颊侧至舌侧并向下与牙体长轴分别呈30°、45°、60°角,垂直于牙体长轴且向舌侧的90°角。比较两种模型种植体、周围骨组织的应力分布情况以及修复体的位移变化。结果在相同条件加载下,与椭圆形接触面模型相比,梯形接触面模型种植体及周围骨组织的最大等效应力和修复体的最大位移均较小,且应力分布更均匀,应力集中范围更小,随着加载角度的增加,此种趋势更明显,即当加载角度增大至90°时,椭圆形接触面模型种植体及周围骨组织的最大等效应力、修复体的最大位移分别为196和101 MPa、0.196 mm,而梯形接触面模型分别为157和72 MPa、0.164 mm。结论下颌中切牙种植单端固定桥桥体与邻牙的梯形接触面有利于减小杠杆作用对种植体及周围骨组织产生的影响。 展开更多
关键词 有限元分析 牙种植体 义齿 局部 固定 牙应力分析
种植固定修复四种粘接固位形式的粘接剂流动状态及修复体固位力的比较
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作者 孙斌 李雨洁 +4 位作者 孟兆理 曹巧 段路路 姚楠 周秦 《中华口腔医学杂志》 CAS CSCD 北大核心 2019年第7期469-474,共6页
目的研究种植固定修复中不同粘接固位形式对粘接剂流动状态及修复体固位力的影响。方法选取4种常见的粘接固位形式,分为对照组(传统粘接固位)、开孔组([牙合]面开孔)、排溢孔组(舌面开孔)、代型组(使用粘接代型),选用树脂加强型玻璃离... 目的研究种植固定修复中不同粘接固位形式对粘接剂流动状态及修复体固位力的影响。方法选取4种常见的粘接固位形式,分为对照组(传统粘接固位)、开孔组([牙合]面开孔)、排溢孔组(舌面开孔)、代型组(使用粘接代型),选用树脂加强型玻璃离子粘接剂;建立计算流体力学二维分析模型,利用计算流体力学模拟粘接过程中粘接剂的流动状态,并计算粘接剂间隙内粘接剂的充盈比及修复体边缘下粘接剂的量。根据组别加工40个全瓷修复体(每组10个),完成相应粘接,进行拉伸实验,比较各组修复体固位力。结果计算流体力学分析显示,粘接剂间隙内粘接剂的充盈比从大到小依次为排溢孔组、开孔组、代型组、对照组,修复体边缘下粘接剂的量从小到大依次为代型组、开孔组、排溢孔组、对照组。对照组、开孔组、排溢孔组、代型组修复体固位力分别为(240.7±33.9)、(278.2±59.1)、(292.9±47.9)、(262.8±59.4)N,其中排溢孔组显著大于对照组(P=0.029),其余组间差异均无统计学意义(P>0.05)。结论3种改良的粘接固位形式均能有效减少种植固定修复粘接过程中粘接剂的龈下溢出,并改善粘接剂在粘接剂间隙内的充盈情况,保证修复体固位力。临床应根据种植体三维位置、修复体边缘位置等实际情况选择合适的粘接固位形式。 展开更多
关键词 固位 义齿 局部 固定 玻璃离聚物粘固剂 牙种植 计算流体力学
Exis tence and st ability of μ-pseudo almost automorphic solutions for stochastic evolution equations
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作者 Jing CUI Wenping RONG 《中国数学前沿:英文版》 SCIE CSCD 2019年第2期261-280,共20页
We introduce a new concept of μ-pseudo almost automorphic processes in p-th mean sense by employing the measure theory, and present some results on the functional space of such processes like completeness and composi... We introduce a new concept of μ-pseudo almost automorphic processes in p-th mean sense by employing the measure theory, and present some results on the functional space of such processes like completeness and composition theorems. Under some conditions, we establish the existence, uniqueness, and the global exponentially stability of μ-pseudo almost automorphic mild solutions for a class of nonlinear stochastic evolution equations driven by Brownian motion in a separable Hilbert space. 展开更多
关键词 STOCHASTIC evolution equation μ-pseudo ALMOST automorphic process fixed point THEOREM
On Generalized Algebraic Cone Metric Spaces and Fixed Point Theorems
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作者 Qing MENG 《数学年刊:B辑英文版》 SCIE CSCD 2019年第3期429-438,共10页
In this paper, the author first introduces the concept of generalized algebraic cone metric spaces and some elementary results concerning generalized algebraic cone metric spaces. Next, by using these results, some ne... In this paper, the author first introduces the concept of generalized algebraic cone metric spaces and some elementary results concerning generalized algebraic cone metric spaces. Next, by using these results, some new fixed point theorems on generalized(complete) algebraic cone metric spaces are proved and an example is given. As a consequence, the main results generalize the corresponding results in complete algebraic cone metric spaces and generalized complete metric spaces. 展开更多
关键词 GENERALIZED ALGEBRAIC CONE metric space CANONICAL DECOMPOSITION Fixed point
Bootstrap LM Tests for Spatial Dependence in Panel Data Models with Fixed Effects 预览
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作者 Bianling OU Zhihe LONG Wenqian LI 《系统科学与信息学报:英文版》 CSCD 2019年第4期330-343,共14页
This paper applies bootstrap methods to LM tests(including LM-lag test and LM-error test) for spatial dependence in panel data models with fixed effects, and removes fixed effects based on orthogonal transformation me... This paper applies bootstrap methods to LM tests(including LM-lag test and LM-error test) for spatial dependence in panel data models with fixed effects, and removes fixed effects based on orthogonal transformation method proposed by Lee and Yu(2010). The consistencies of LM tests and their bootstrap versions are proved, and then some asymptotic refinements of bootstrap LM tests are obtained. It shows that the convergence rate of bootstrap LM tests is O((N T)-2) and that of fast double bootstrap LM tests is O((NT)-5/2). Extensive Monte Carlo experiments suggest that,compared to aysmptotic LM tests, the size of bootstrap LM tests gets closer to the nominal level of signifiance, and the power of bootstrap LM tests is higher, especially in the cases with small spatial correlation. Moreover, when the error is not normal or with heteroskedastic, asymptotic LM tests suffer from severe size distortion, but the size of bootstrap LM tests is close to the nominal significance level.Bootstrap LM tests are superior to aysmptotic LM tests in terms of size and power. 展开更多
关键词 fast double BOOTSTRAP LM-lag TEST LM-error TEST PANEL data models with fixed effects Monte Carlo simulation
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A study of stability and bifurcation analysis in discrete-time predator—prey system involving the Allee effect
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作者 Seval Isik 《生物数学学报:英文版》 2019年第1期255-269,共15页
This paper deals with a discrete-time predator-prey system which is subject to an Allee effect on prey.We investigate the existence and uniqueness and find parametric conditions for local asymptotic stability of fixed... This paper deals with a discrete-time predator-prey system which is subject to an Allee effect on prey.We investigate the existence and uniqueness and find parametric conditions for local asymptotic stability of fixed points of the discrete dynamic system.Moreover,using bifurcation theory,it is shown that the system undergoes Neimark-Sacker bifurcation in a small neighborhood of the unique positive fixed point and an inv aria nt circle will appear.Then the direction of bifurcation is given.Furthermore,numerical analysis is provided to illustrate the theoretical discussions with the help of Matlab packages.Thus,the main theoretical results are supported with numerical simulations. 展开更多
关键词 PREDATOR-PREY SYSTEM fixed point stability Neimark-Sacker BIFURCATION Allee effect
Pregnancy Rate of Bunaji Cows in a Fixed Time AI Synchronization Protocol Using Ovatide 预览
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作者 Ubah Simon Azubuike Rekwot Peter Ibrahim +6 位作者 Adewuyi Abdulmujeeb Bode Omontese Bobwealth Oakina Adeyeye Adewale Ayodeji Columbus Philemon Kwinjoh Abah Owoicho Kenneth Agbonu Oluwa Adikpe Ejiofor Charles Ejike 《农业科学与技术:A》 2019年第1期46-55,共10页
This study accessed the reproductive performance of Bunaji cows in an Ovsynch protocol involving ovatide.Bunaji cows(n=16)aged 4-6 years and weighing between 250-350 kg with body condition scores(BCS)of 2.5-3.5 were u... This study accessed the reproductive performance of Bunaji cows in an Ovsynch protocol involving ovatide.Bunaji cows(n=16)aged 4-6 years and weighing between 250-350 kg with body condition scores(BCS)of 2.5-3.5 were used.There were two treatment groups for synchronization of ovulation.Treatment group 1 comprising Bunaji(n=8)received 50μg of gonadotropin releasing hormone(GnRH)(Cystorelin)and 25 mg of PGF2α.While,treatment group 2 comprising Bunaji(n=8)received 50μg of ovatide and 25 mg of PGF2α.All cows from both treatment groups were inseminated at 16 h after each second GnRH or ovatide injections.Cows that showed mucus discharge from the vagina on the day of artificial insemination(AI)were recorded as well as those that had patent cervix.Cervical dilation was measured by taking note of the cows that had mid cervix insemination due to non-passage of the AI gun through the cervix.Transrectal palpation was conducted twice at a month interval to select cycling cows within 5-12 d of the estrous cycle before initiating Ovsynch protocol.It was repeated on day 45 post AI to confirm pregnancies in animals.Results showed that the rate of mucus discharge from the vagina was 37.5%and 87.5%for ovatide and Cystorelin,respectively;while the rate of cervical dilation were 75%and 87.5%for ovatide and Cystorelin,respectively(p>0.05),and pregnancy rates were 0%and 12.5%for ovatide and Cystorelin,respectively.There were no significant differences between the two groups.It was concluded that treatment of Bunaji cows with 50μg ovatide in Ovsynh protocol has heat and ovulation synchronization potentials and zero pregnancy rate.It was recommended that further studies be carried out using graded doses of 50,100 and 150μg of ovatide in a fixed time AI synchronization protocol in Bunaji cows,to tap the potentials of the hormone in manipulation of bovine reproduction. 展开更多
关键词 PREGNANCY ovatide fixed TIME AI SYNCHRONIZATION COWS
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Closed-Loop Iterative Learning Control for Discrete Singular Systems with Fixed Initial Shift
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作者 GU Panpan TIAN Senping LIU Qian 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2019年第2期577-587,共11页
This paper deals with the problem of iterative learning control for a class of discrete singular systems with fixed initial shift. According to the characteristics of the discrete singular systems, a closed-loop learn... This paper deals with the problem of iterative learning control for a class of discrete singular systems with fixed initial shift. According to the characteristics of the discrete singular systems, a closed-loop learning algorithm is proposed and the corresponding state limiting trajectory is presented.It is shown that the algorithm can guarantee that the system state converges uniformly to the state limiting trajectory on the whole time interval. Then the initial rectifying strategy is introduced to the discrete singular systems for eliminating the effect of the fixed initial shift. Under the action of the initial rectifying strategy, the system state can converge to the desired state trajectory within the pre-specified finite time interval no matter what value the fixed initial shift takes. Finally, a numerical example is given to illustrate the effectiveness of the proposed approach. 展开更多
关键词 CLOSED-LOOP LEARNING algorithm discrete singular systems fixed INITIAL SHIFT ITERATIVE LEARNING control
New results for a Lasota-Wazewska model
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作者 Farouk Cherif Mohsen Miraoui 《生物数学学报:英文版》 2019年第2期143-162,共20页
In nature there is no phenomenon that is purely periodic,and this gives the idea to consider the measure pseudo almost periodic oscillation.In this paper,by employing a suitable fixed point theorem,the proper ties of ... In nature there is no phenomenon that is purely periodic,and this gives the idea to consider the measure pseudo almost periodic oscillation.In this paper,by employing a suitable fixed point theorem,the proper ties of the measure pseudo almost periodic functions and differential inequality,we investigate the existence and uniqueness of the measure pseudo almost periodic solutions for some models of Lasota-Wazewska equation with measure pseudo almost periodic coefficients and mixed delays.We suppose that the linear part has almost periodic and the nonlinear part is assumed to be measure pseudo almost periodic.Moreover,the global attractivity and the exponential stability of the measure pseudo almost periodic solutions are also considered for the system.As application,an illustrative numerical example is given to demonstrate the effectiveness of the obtained results. 展开更多
关键词 LASOTA Wazewska model MEASURE PSEUDO ALMOST PERIODIC function fixed point THEOREM
The Flow Behavior of Red Blood Cell Reduced Deformability in Microchannel
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作者 Fen Li Rui Duan Hui Li 《医用生物力学》 CAS CSCD 北大核心 2019年第A01期116-117,共2页
Blood cells are mainly(~99%)comprised of red blood cells.The most remarkable properties of are their high deformability,which allow they flow through microcapillaries of diameter even smaller than their size.The RBC’... Blood cells are mainly(~99%)comprised of red blood cells.The most remarkable properties of are their high deformability,which allow they flow through microcapillaries of diameter even smaller than their size.The RBC’s remarkable mechanical properties originate from the unique architecture of its membrane.To study the mechanism of RBC’s deformability,a commonly adopted approach is to localize the cytoskeleton protein by immunofluorescence,followed by exploring the changes of cytoskeleton protein during cell deformation.During this process,the fixed treatment of RBC using GA and PFA is of great importance.However,RBC’s deformability is reduced by the fixation process and skeletal protein of membrane is changed accordingly.The flow behavior of red RBCs through the microchannel also changed.Given the difficulty of observing RBC flow in vivo,in vitro simulation by virtue of microfluidic devices provides a feasible alternative.An important physiological phenomenon of the blood flow is the formation of cell free layer(CFL),with RBCs show a tendency to concentrate towards the central axis of the pipeline and move faster than the plasma layer.However,this phenomena is weaken if the stiffness of the membrane increase,which occurs in some disease,such as hereditary spherocytosis and hereditary elliptocytosis.To study the effects of GA and PFA fix treatment on RBC deformability,a microfluidic platform is employed to measuring the CFL and flow velocity of blood flow in this work.The PDMS micro flow channel used is 100 micrometers in width and 50 micrometers in deep.The RBC suspension is fed into the flow channel by the injection pump(NE-1000.USA),and the experiments are observed and recorded by the inverted microscope(IX70,Olympus,Japan)and high-speed camera(Memrecam GX-1,NAC,Japan)system.Three GA concentrations,i.e.,0.000 5,0.000 75,and 0.001 wt.%were used.Meanwhile,the effect of PFA at a concentration of 2wt.%work with GA was also investigated.Images of the flowing RBCs are processed mainly based on Memrecam GXLink.Th 展开更多
关键词 red BLOOD CELL micro channel fixed treatment CELL free layer VELOCITY distribution
IMS固话组网与用户接入方案研究 预览
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作者 焦楠 《信息与电脑》 2019年第10期171-173,共3页
随着网络技术的普及应用和通信技术的开发,固定通信技术设备与移动技术通信设备不可避免地实行大融合,优势互补,打破技术局限,使通信设备的服务性能更具人性化。IMS固化组网与用户接入,在技术上秉承了控制和业务相分离、承载与控制相分... 随着网络技术的普及应用和通信技术的开发,固定通信技术设备与移动技术通信设备不可避免地实行大融合,优势互补,打破技术局限,使通信设备的服务性能更具人性化。IMS固化组网与用户接入,在技术上秉承了控制和业务相分离、承载与控制相分离的理念,而且网络解聚更充分,结构更完美,进一步提高了服务性能。笔者结合工作实际对IMS固话组网与用户接入方案进行了研究。 展开更多
关键词 固定 专网 IMS 接入
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具有Banach代数的半序锥b-度量空间的一类改进(英文) 预览
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作者 韩艳 许绍元 董延寿 《数学季刊:英文版》 2019年第1期43-51,共9页
The purpose of this paper is to improve some famous theorems for contractive mapping from ρ(α + β) ∈ [0,1/s) to ρ(α + β) ∈ [0, 1) in ordered cone b-metric spaces over Banach algebras with coefficient s ≥ 1(ρ... The purpose of this paper is to improve some famous theorems for contractive mapping from ρ(α + β) ∈ [0,1/s) to ρ(α + β) ∈ [0, 1) in ordered cone b-metric spaces over Banach algebras with coefficient s ≥ 1(ρ(x) is the spectral radius of the generalized Lipschitz constant x). Moreover, some similar improvements in ordered cone b-metric spaces are also obtained, which from α + β∈ [0,1/s) to α + β∈ [0, 1). Some examples are given to support that our new results are genuine improvements and generalizations. 展开更多
关键词 Cone b-metric spaces over BANACH ALGEBRAS c-distance generalized LIPSCHITZ MAPPINGS fixed point
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GLOBAL EXISTENCE OF MILD SOLUTIONS FOR THE ELASTIC SYSTEM WITH STRUCTURAL DAMPING
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作者 Wei Shi 《应用数学年刊:英文版》 2019年第2期180-188,共9页
In this paper, we study the global existence of mild solutions for the semilinear initial-value problems of second order evolution equations, which can model an elastic system with structural damping. This discussion ... In this paper, we study the global existence of mild solutions for the semilinear initial-value problems of second order evolution equations, which can model an elastic system with structural damping. This discussion is based on the operator semigroups theory and the Leray-Schauder fixed point theorem.In addition, an example is presented to illustrate our theoretical result. 展开更多
关键词 C0-SEMIGROUP ELASTIC systems structural DAMPING MILD solution fixed POINT
用不同方法固定中心静脉导管的效果对比 预览
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作者 郭琴 《当代医药论丛》 2019年第3期235-236,共2页
目的:比较使用不同方法固定中心静脉导管的效果。方法:选取2016年7月至8月期间在四川省肿瘤医院进行中心静脉置管的1148例患者作为研究对象。将2016年7月在四川省肿瘤医院进行中心静脉置管的576例患者作为对照组。将2016年8月在四川省... 目的:比较使用不同方法固定中心静脉导管的效果。方法:选取2016年7月至8月期间在四川省肿瘤医院进行中心静脉置管的1148例患者作为研究对象。将2016年7月在四川省肿瘤医院进行中心静脉置管的576例患者作为对照组。将2016年8月在四川省肿瘤医院进行中心静脉置管的572例患者作为观察组。为对照组患者使用思乐扣将中心静脉导管固定为“U”或“S”型。为观察组患者使用思乐扣将中心静脉导管固定为“I”形。然后观察两组患者留置导管期间发生导管脱出或移位、导管相关性感染的情况及置管期间的舒适度。结果:置管期间,观察组患者导管脱出或移位的发生率及导管相关性感染的发生率均低于对照组患者,P<0.05。两组患者置管期间的舒适率相比,P>0.05。结论:为进行中心静脉置管的患者使用思乐扣将中心静脉导管固定为“I”形可降低其导管脱出或移位、导管相关性感染的发生率,且不影响其置管期间的舒适度。 展开更多
关键词 思乐扣 中心静脉导管 固定
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Short-term differences in anterior knee pain and clinical outcomes between rotating and fixed platform posterior stabilized total knee arthroplasty with a new femoral component design 预览
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作者 Marco Bigoni Nicolo Zanchi +3 位作者 Marco Turati Gabriele Pirovano Giovanni Zatti Daniele Munegato 《世界骨科杂志(英文版)》 2019年第3期128-136,共9页
AIM To compare rotating versus fixed-bearing Press-Fit Condylar(PFC)Sigma posterior stabilized(PS)total knee arthroplasty(TKA)with the new“J curve”femoral design in terms of clinical outcomes and anterior knee pain.... AIM To compare rotating versus fixed-bearing Press-Fit Condylar(PFC)Sigma posterior stabilized(PS)total knee arthroplasty(TKA)with the new“J curve”femoral design in terms of clinical outcomes and anterior knee pain.METHODS We retrospectively analyzed 39 patients who underwent primary total knee replacement surgery for knee osteoarthritis using the PFC Sigma PS TKA with either fixed(FP group,20 cases)or rotating platform(RP group,19 cases)treated between 2009 and 2013 by the same surgeon.The two groups were homogeneous for age,gender,weight,American Society of Anesthesiologists status,preoperative clinical and functional scores,and prosthetic alignment at two years after surgery.We analyzed clinical outcomes score at two years follow-up using Knee Society Score(KSS),Knee Injury and Osteoarthritis Outcome Score(KOOS),Knee Performance Score,Short Form(SF)36,and anterior knee pain assessed by the Hospital for Special Surgery(HSS)patellar score.RESULTS No differences were found in KSS,Knee Performance Score,and SF-36 outcome scores.A statistically significant difference was found in the HSS Patella score objective(FP:22.36;RP:28.75;P<0.05),HSS Patella score total(FP:73.68;RP:86.50;P<0.05),and KOOS symptoms(FP:73.49;RP:86.44;P<0.05).CONCLUSION Rotating platform in PFC Sigma PS TKA appears to reduce the short-term incidence of anterior knee pain compared to the fixed platform. 展开更多
关键词 Total KNEE ARTHROPLASTY Anterior KNEE pain ROTATING PLATFORM GONARTHROSIS Fixed PLATFORM
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聚醚醚酮及其复合材料在口腔固定义齿支架中的应用进展
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作者 曹彦泽 魏洪波 +2 位作者 王金 于卓 李德华 《中华口腔医学杂志》 CAS CSCD 北大核心 2019年第11期773-777,共5页
作为一种新型生物医学材料,聚醚醚酮具备优异的力学性能、化学稳定性和生物安全性,已应用于口腔医学领域。本文就口腔固定义齿支架用聚醚醚酮及其复合材料的基本性能、加工工艺、粘接性能和应用现状进行综述,并对增材制造加工口腔固定... 作为一种新型生物医学材料,聚醚醚酮具备优异的力学性能、化学稳定性和生物安全性,已应用于口腔医学领域。本文就口腔固定义齿支架用聚醚醚酮及其复合材料的基本性能、加工工艺、粘接性能和应用现状进行综述,并对增材制造加工口腔固定义齿支架用聚醚醚酮及其复合材料的前景作一展望。 展开更多
关键词 义齿 局部 固定 牙科材料 聚醚醚酮 支架
Combined effects of axial load and temperature on finite deformation of incompressible thermo-hyperelastic cylinder 预览
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作者 Jie XU Xuegang YUAN +2 位作者 Hongwu ZHANG Zhentao ZHAO Wei ZHAO 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第4期499-514,共16页
A finite deformation problem is examined for a cylinder composed of a class of incompressible thermo-hyperelastic Mooney-Rivlin materials under an equal axial load at its two fixed ends and a temperature field at its ... A finite deformation problem is examined for a cylinder composed of a class of incompressible thermo-hyperelastic Mooney-Rivlin materials under an equal axial load at its two fixed ends and a temperature field at its lateral boundary.Firstly,a thermo-mechanical coupling term is taken into account in the strain energy density function,and a governing equation of the problem is obtained.Secondly,an implicit analytical solution is derived by using the incompressibility and the boundary conditions.Significantly,nu-merical examples show that the middle portion of the cylinder undergoes almost a uniform radial deformation.However,the deformation near the two ends varies remarkably along the axial direction for relatively large axial loads.In addition,the rising temperature can increase the deformation of structures,and its influence is linear approximately.Specially,in the case of tensile load,the jump increase of the axial deformation may occur. 展开更多
关键词 INCOMPRESSIBLE thermo-hyperelastic CYLINDER fixed end axial load implicit analytical solution tensile instability
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Pregnancy outcome of lactating dairy cows assigned for Presynch-Ovsynchsynchronization program and inseminated either at detected standing heat or at scheduled fixed time
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作者 Abdel-Tawab Abdel-Razek Yassyn Khalil Mahmoud Mohamed Hussein 《亚太生殖杂志(英文版)》 2019年第4期181-186,共6页
Objective: To determine if insemination at standing heat results in a similar or higher pregnancy rate compared with fixed time artificial insemination, and to study some factors affecting the pregnancy rate. Methods:... Objective: To determine if insemination at standing heat results in a similar or higher pregnancy rate compared with fixed time artificial insemination, and to study some factors affecting the pregnancy rate. Methods: A total of 8944 inseminations were included in this study, from which 6823 inseminations were done in Holstein cows and 2121 inseminations were performed in Simmental cows. All cows were subjected to a Presynch-Ovsynch protocol. Cows detected in estrus (n=7424) were artificially inseminated, whereas cows not observed in estrus (n=1520) were submitted to fixed time artificial insemination. Results: The overall pregnancy rate of cows inseminated on the basis of the detected standing heat was comparable to that recorded for cows receiving fixed time artificial insemination. A higher pregnancy rate was recorded for cows during cold months than that recorded during hot months (P=0.000). A higher pregnancy rate was recorded for Simmental compared with that recorded for Holstein cows (P=0.001). Regarding parity, significant differences in the pregnancy rate were detected between primiparous and multiparous cows (P=0.040). In addition, artificial insemination technicians had no sigificant effect on pregnancy rate (P>0.05). Meanwhile, the used artificial insemination sires significantly (P=0.000) impacted the pregnancy rate. Conclusions: Insemination of cows detected in standing heat prior to predetermined fixed time results in similar pregnancy outcome and decreases days to the first service compared with insemination at the scheduled fixed time at the end of the Presynch-Ovsynch synchronization program. The overall pregnancy outcome is not affected by the breeding program, but it is highly impacted by cow's breed, parity, artificial insemination sire and breeding season. 展开更多
关键词 Dairy cow Presynch OVSYNCH STANDING HEAT Fixed TIME artificial INSEMINATION
ON FIXED POINTS OF MEROMORPHIC FUNCTIONS f(z) AND f(z + c),△cf(z) 预览
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作者 蓝双婷 陈宗煊 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第5期1277-1289,共13页
Let c be a nonzero constant and f(z) be a transcendental meromorphic function of finite order. Under some conditions, we study the relationships between the exponent of convergence of fixed points of f(z), its shift f... Let c be a nonzero constant and f(z) be a transcendental meromorphic function of finite order. Under some conditions, we study the relationships between the exponent of convergence of fixed points of f(z), its shift f(z +c) and forward differences △c^n f(z), n ∈ N^+. 展开更多
关键词 fixed points MEROMORPHIC function DIFFERENCES
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Multiple Positive Solutions to Singular Fractional Differential System with Riemann-Stieltjes Integral Boundary Condition 预览
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作者 Zhang Hai-yan Li Yao-hong 《数学研究通讯:英文版》 CSCD 2019年第3期208-218,共11页
In this paper, we study a class of singular fractional differential system with Riemann-Stieltjes integral boundary condition by constructing a new cone and using Leggett-Williams fixed point theorem. The existence of... In this paper, we study a class of singular fractional differential system with Riemann-Stieltjes integral boundary condition by constructing a new cone and using Leggett-Williams fixed point theorem. The existence of multiple positive solutions is obtained. An example is presented to illustrate our main results. 展开更多
关键词 FRACTIONAL differential equation positive solution INTEGRAL boundary condition fixed point THEOREM
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