Prosthetic rehabilitation of a missing tooth with tilted abutments is yet an enigmatic and less unconventionally sought-after treatment strategy. Many methods have been previously reviewed over the years. This clinica...Prosthetic rehabilitation of a missing tooth with tilted abutments is yet an enigmatic and less unconventionally sought-after treatment strategy. Many methods have been previously reviewed over the years. This clinical report aims to integrate the principles of the segmented fixed dental prosthesis into a digital workflow. It elucidates the rehabilitation using a split-pontic design that mitigates the issue of developing a common path of insertion without much compromise to the tooth preparation to derive parallel prepared walls. This prosthetic design rather incorporates a common path of insertion into the pontic in the form of a key-keyway non-rigid connector design.展开更多
High-speed axial piston pumps are hydraulic power supplies for electro-hydrostatic actuators(EHAs). The efficiency of a pump directly affects the operating performance of an EHA, and an understanding of the physical p...High-speed axial piston pumps are hydraulic power supplies for electro-hydrostatic actuators(EHAs). The efficiency of a pump directly affects the operating performance of an EHA, and an understanding of the physical phenomena occurring in the cylinder/valve plate interface is essential to investigate energy dissipation. The effects of the splined shaft bending rigidity on the cylinder tilt behaviour in an EHA pump need to be considered, because the deflection and radial expansion of a steel shaft rotating at a high speed cannot be ignored. This paper proposes a new mathematical model to predict the cylinder tilt behaviour by establishing a quantitative relationship between the splined shaft deflection, the cylinder tilt angle, and the tilt azimuth angle. The moments exerted by the splined shaft are included in the equilibrium equation of the cylinder. The effects of solid and hollow splined shafts equipped in an EHA pump prototype are compared at variable speeds of 5000–10,000 r/min. With a weight saving of 29.7%, the hollow shaft is experimentally found to have almost no influence on the volumetric efficiency, but to reduce the mechanical efficiency by 0.6–2.4%. The results agree with the trivial differences of the simulated central gap heights of the interface between the two shafts and the enlargement of the simulated tilt angles by the hollow shaft. The findings could guide designs of the cylinder/valve plate interface and the splined shaft to improve both the efficiency and power density of an EHA pump.展开更多
目的本研究回顾性分析了腰椎僵直对预行全髋关节置换术(total hip arthroplasty,THA)患者姿势性骨盆活动度的影响。方法回顾性分析2018年10月至2021年10月因股骨头坏死于我院预行THA患者的术前临床资料,共纳入45例患者。男性20例,女性25...目的本研究回顾性分析了腰椎僵直对预行全髋关节置换术(total hip arthroplasty,THA)患者姿势性骨盆活动度的影响。方法回顾性分析2018年10月至2021年10月因股骨头坏死于我院预行THA患者的术前临床资料,共纳入45例患者。男性20例,女性25例;年龄55~78岁,平均年龄(65.7±6.3)岁。根据术前骨盆入射角(pelvic incidence,PI)与腰椎前凸(lumbar lordosis,LL)之间的差值PI-LL(≤10°或>10°)将患者分为两组。腰椎僵直组(21例)定义为PI-LL>10°,非腰椎僵直组(24例)定义为PI-LL≤10°。根据患者在每种姿势下的侧位X线片测量仰卧、站立及坐位的骨盆倾斜角(pelvic tilt,PT)及骨盆活动度(ΔPT)、PI和腰椎前凸LL。比较两组PT及ΔPT的差异。结果腰椎僵直组在仰卧位及站立位时的PT要明显大于非腰椎僵直组,两组比较差异有统计学意义(P<0.05),而坐位时两组比较,差异无统计学意义(P=0.44)。腰椎僵直组从站立位变为坐位时骨盆明显前倾(-7.17±12.11)°,而非腰椎僵直组患者骨盆前倾变化较小(-1.04±12.52)°。两组ΔPT比较,差异有统计学意义。当患者从站立位到仰卧位时,腰椎僵直组(-6.36±4.07)°与非腰椎僵直组(-2.79±5.47)°的ΔPT相比较,也有明显更大角度的骨盆前倾(P<0.05)。结论与非腰椎僵直相比,腰椎僵直患者在改变姿势时骨盆活动度明显更高。这意味着动态活动期间髋臼位置的更大可变性,并且该患者群体中THA后假体脱位风险增加。展开更多
Let C be a triangulated category which has Auslander-Reiten triangles, and Ra functorially finite rigid subcategory of C. It is well known that there exist Auslander-Reiten sequences in rood R. In this paper, we give ...Let C be a triangulated category which has Auslander-Reiten triangles, and Ra functorially finite rigid subcategory of C. It is well known that there exist Auslander-Reiten sequences in rood R. In this paper, we give explicitly the relations between the Auslander-Reiten translations, sequences in mod R and the Auslander-Reiten functors, triangles in C, respectively. Furthermore, if T is a cluster-tilting subcategory of C and mod T- is a Frobenius category, we also get the Auslander-Reiten functor and the translation functor of mod T- corresponding to the ones in C. As a consequence, we get that if the quotient of a d-Calabi-Yau triangulated category modulo a cluster tilting subcategory is Probenius, then its stable category is （2d-1）-Calabi-Yau. This result was first proved by Keller and Reiten in the case d= 2, and then by Dugas in the general case, using different methods. 2010 Mathematics Subject Classification： 16G20, 16G70展开更多
文摘Prosthetic rehabilitation of a missing tooth with tilted abutments is yet an enigmatic and less unconventionally sought-after treatment strategy. Many methods have been previously reviewed over the years. This clinical report aims to integrate the principles of the segmented fixed dental prosthesis into a digital workflow. It elucidates the rehabilitation using a split-pontic design that mitigates the issue of developing a common path of insertion without much compromise to the tooth preparation to derive parallel prepared walls. This prosthetic design rather incorporates a common path of insertion into the pontic in the form of a key-keyway non-rigid connector design.
基金the financial supports received from the National Basic Research Program of China (973 Program) (No. 2014CB046403)the National Natural Science Foundation of China (Nos. U1509204 and 51605425)
文摘High-speed axial piston pumps are hydraulic power supplies for electro-hydrostatic actuators(EHAs). The efficiency of a pump directly affects the operating performance of an EHA, and an understanding of the physical phenomena occurring in the cylinder/valve plate interface is essential to investigate energy dissipation. The effects of the splined shaft bending rigidity on the cylinder tilt behaviour in an EHA pump need to be considered, because the deflection and radial expansion of a steel shaft rotating at a high speed cannot be ignored. This paper proposes a new mathematical model to predict the cylinder tilt behaviour by establishing a quantitative relationship between the splined shaft deflection, the cylinder tilt angle, and the tilt azimuth angle. The moments exerted by the splined shaft are included in the equilibrium equation of the cylinder. The effects of solid and hollow splined shafts equipped in an EHA pump prototype are compared at variable speeds of 5000–10,000 r/min. With a weight saving of 29.7%, the hollow shaft is experimentally found to have almost no influence on the volumetric efficiency, but to reduce the mechanical efficiency by 0.6–2.4%. The results agree with the trivial differences of the simulated central gap heights of the interface between the two shafts and the enlargement of the simulated tilt angles by the hollow shaft. The findings could guide designs of the cylinder/valve plate interface and the splined shaft to improve both the efficiency and power density of an EHA pump.
文摘Let C be a triangulated category which has Auslander-Reiten triangles, and Ra functorially finite rigid subcategory of C. It is well known that there exist Auslander-Reiten sequences in rood R. In this paper, we give explicitly the relations between the Auslander-Reiten translations, sequences in mod R and the Auslander-Reiten functors, triangles in C, respectively. Furthermore, if T is a cluster-tilting subcategory of C and mod T- is a Frobenius category, we also get the Auslander-Reiten functor and the translation functor of mod T- corresponding to the ones in C. As a consequence, we get that if the quotient of a d-Calabi-Yau triangulated category modulo a cluster tilting subcategory is Probenius, then its stable category is （2d-1）-Calabi-Yau. This result was first proved by Keller and Reiten in the case d= 2, and then by Dugas in the general case, using different methods. 2010 Mathematics Subject Classification： 16G20, 16G70
