The challenging conditions at which gas turbine engines operate mean that careful management of component temperatures is necessary, in order to ensure component integrity and reasonable service life. Pressurised flow...The challenging conditions at which gas turbine engines operate mean that careful management of component temperatures is necessary, in order to ensure component integrity and reasonable service life. Pressurised flows extracted from the compressor can be used for cooling, sealing and balancing of components throughout the engine. Cooling is typically necessary for some combustor and turbine components, and sealing flows may be needed to exclude high temperature gases. In addition to cooling and sealing requirements, there is also a need to balance thrust loads in an engine, to limit loads on bearings, arising from the pressure differentials across compressor and turbine disc assemblies. The diverse tasks of cooling, sealing and balancing are generally assigned to a system known as the internal air system or secondary flow system. This paper describes the technologies associated with this system for both industrial gas turbine engines and aero-engines, and the current state of the art and challenges in component and subsystem design.展开更多
The external morphology and internal oral features of the tadpoles of Kaloula rugifera and K. borealis are described in this paper. Similarities between these two larvae include external morphology, oral disc, interna...The external morphology and internal oral features of the tadpoles of Kaloula rugifera and K. borealis are described in this paper. Similarities between these two larvae include external morphology, oral disc, internal oral features(floor and roof), terminal mouth, lateral eyes, single midventral spiracle, absence of keratinized jaw sheaths and labial teeth, absence of lingual papillae and postnarial arena, while the body of K. rugifera is bigger than that of K. borealis at stages from 36 to 39 and the number of papillae in the buccal cavity is 12–19 and 9–16, respectively in the two species. All the similarities and differences of the two species illustrate that the tadpoles within the family Microhylidae could be attributed to assistance in clarifying a certain taxonomic treatment in Microhylidae.展开更多
Scratch test and friction test were performed to evaluate the internal and external interface behaviors of TiAISiN coating, respectively. The critical compressive and shearing stress of coating failure during scratch ...Scratch test and friction test were performed to evaluate the internal and external interface behaviors of TiAISiN coating, respectively. The critical compressive and shearing stress of coating failure during scratch test were calculated and the values are 30.84 MPa and 4.98 MPa respectively. The average friction coefficients of TiAISiN coat- ing against 2Crl2Ni4Mo3VNbN steel are 0.70 （sliding speed 50 m/rain）, 0.63 （sliding speed 100 m/min）, and 0.81 （sliding speed 150 m/min）. The elements diffusion was analyzed by EDS. A1 and Si element of coating material dif- fuse to the steel disc, except Ti element. The oxidation decreases with the increase of sliding speed, but the adhesion increases with the increase of sliding speed. More A1 element diffuses to the steel disc at the high sliding speed, but the diffusion of Si element keeps almost constant at dlfferent sliding speeds.展开更多
目的通过建立非融合技术人工椎间盘（artificial disk of non-fusion technology,ADNFT）的山羊体内模型,研究其喷钛涂层骨长入、固定效果及非融合技术,为临床应用提供可行性证据。方法选择10只成年健康山羊作为实验对象,体重35~55 kg,...目的通过建立非融合技术人工椎间盘（artificial disk of non-fusion technology,ADNFT）的山羊体内模型,研究其喷钛涂层骨长入、固定效果及非融合技术,为临床应用提供可行性证据。方法选择10只成年健康山羊作为实验对象,体重35~55 kg,羊龄10~24个月,随机分成A、B两组,每组各5只,经腰椎前外侧入路,行非融合技术人工椎间盘置换术,A、B组分别在术后3、6个月行腰椎正侧位的影像学检查,并分别在术后3、6个月取出包括假体在内的周围骨组织和软组织,常规制作标本后分别行病理、扫描电镜检查。通过腰椎影像学、病理及扫描电镜评价假体的固定效果、喷钛涂层骨长入及人工椎间盘的活动度。结果 10只山羊均建模成功,术后取出假体及周围组织的病理结果及电镜下可见假体喷钛涂层骨组织长入良好,人工椎间盘的钴铬钼合金、硅胶及喷钛涂层与周围组织相容性良好,腰椎X线片示假体位置良好,无松动,人工椎间盘有一定的活动度。结论非融合技术人工椎间盘的喷钛涂层骨长入良好,与椎体的固定效果可靠,材料的组织相容性好,具有非融合技术的效果。展开更多
Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patie...Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patients with discogenic low back pain were the formation of the zones of vascularized granulation tissue, with extensive innervation in fissures extending from the outer part of the annulus into the nucleus pulposus. Studies suggested that the degeneration of the painful disc might originate from the injury and subsequent repair of annulus fibrosus. Growth factors such as basic fibroblast growth factor, transforming growth factor β1, and connective tissue growth factor, macrophages and mast cells might play a key role in the repair of the injured annulus fibrosus and subsequent disc degeneration. Although there exist controversies about the role of discography as a diagnostic test, provocation discography still is the only available means by which to identify a painful disc. A recent study has classified discogenic low back pain into two types that were annular disruption-induced low back pain and internal endplate disruption-induced low back pain, which have been fully supported by clinical and theoretical bases. Current treatment options for discogenic back pain range from medicinal anti-inflammation strategy to invasive procedures including spine fusion and recently spinal arthroplasty. However, these treatments are limited to relieving symptoms, with no attempt to restore the disc's structure. Recently, there has been a growing interest in developing strategies that aim to repair or regenerate the degenerated disc biologically.展开更多
目的探讨经单侧行病变节段椎管减压、椎间植骨融合、单边椎弓根螺钉内固定治疗腰椎退变性疾病的临床疗效。方法我院2010年1月~2013年12月对35例腰椎退变性疾病采用经单侧减压、椎间植骨融合、单边椎弓根螺钉固定手术治疗。根据JOA评分...目的探讨经单侧行病变节段椎管减压、椎间植骨融合、单边椎弓根螺钉内固定治疗腰椎退变性疾病的临床疗效。方法我院2010年1月~2013年12月对35例腰椎退变性疾病采用经单侧减压、椎间植骨融合、单边椎弓根螺钉固定手术治疗。根据JOA评分法评估术后腰椎功能改善情况,采用视觉模拟评分（visual analog scale,VAS）评估术后疼痛缓解情况,腰椎正侧位X线片及CT扫描了解植骨融合情况。结果随访12~18个月,平均15个月。术前JOA评分（8.2±2.1）分,显著低于术后3个月（20.8±3.8）分（q=22.123,P〈0.05）和术后12个月（21.7±3.9）分（q=23.703,P〈0.05）;VAS评分术前（7.9±2.1）分,显著高于术后3个月（2.4±0.4）分（q=26.107,P〈0.05）和12个月（2.3±0.3）分（q=26.582,P〈0.05）;JOA评分和VAS评分随访期间无显著变化（P〉0.05）。1年后椎间植骨融合率100%,未发现椎弓根螺钉松动、断裂、拔钉等异常。结论经单侧减压、椎间植骨融合联合单边椎弓根螺钉内固定治疗腰椎退变性疾病疗效满意,可在合适病例中推广应用。展开更多
文摘The challenging conditions at which gas turbine engines operate mean that careful management of component temperatures is necessary, in order to ensure component integrity and reasonable service life. Pressurised flows extracted from the compressor can be used for cooling, sealing and balancing of components throughout the engine. Cooling is typically necessary for some combustor and turbine components, and sealing flows may be needed to exclude high temperature gases. In addition to cooling and sealing requirements, there is also a need to balance thrust loads in an engine, to limit loads on bearings, arising from the pressure differentials across compressor and turbine disc assemblies. The diverse tasks of cooling, sealing and balancing are generally assigned to a system known as the internal air system or secondary flow system. This paper describes the technologies associated with this system for both industrial gas turbine engines and aero-engines, and the current state of the art and challenges in component and subsystem design.
基金supported by the National Natural Science Foundation of China(30470206,30870276,30970315)
文摘The external morphology and internal oral features of the tadpoles of Kaloula rugifera and K. borealis are described in this paper. Similarities between these two larvae include external morphology, oral disc, internal oral features(floor and roof), terminal mouth, lateral eyes, single midventral spiracle, absence of keratinized jaw sheaths and labial teeth, absence of lingual papillae and postnarial arena, while the body of K. rugifera is bigger than that of K. borealis at stages from 36 to 39 and the number of papillae in the buccal cavity is 12–19 and 9–16, respectively in the two species. All the similarities and differences of the two species illustrate that the tadpoles within the family Microhylidae could be attributed to assistance in clarifying a certain taxonomic treatment in Microhylidae.
基金Supported by China Postdoctoral Science Foundation(No. 20110490380 and No. 20110490383)Dongfang Turbine Co, Ltd (No. 2011GZ011)State Key Laboratory of Tribology, Tsinghua University (No. SKLT10A01)
文摘Scratch test and friction test were performed to evaluate the internal and external interface behaviors of TiAISiN coating, respectively. The critical compressive and shearing stress of coating failure during scratch test were calculated and the values are 30.84 MPa and 4.98 MPa respectively. The average friction coefficients of TiAISiN coat- ing against 2Crl2Ni4Mo3VNbN steel are 0.70 （sliding speed 50 m/rain）, 0.63 （sliding speed 100 m/min）, and 0.81 （sliding speed 150 m/min）. The elements diffusion was analyzed by EDS. A1 and Si element of coating material dif- fuse to the steel disc, except Ti element. The oxidation decreases with the increase of sliding speed, but the adhesion increases with the increase of sliding speed. More A1 element diffuses to the steel disc at the high sliding speed, but the diffusion of Si element keeps almost constant at dlfferent sliding speeds.
文摘目的通过建立非融合技术人工椎间盘（artificial disk of non-fusion technology,ADNFT）的山羊体内模型,研究其喷钛涂层骨长入、固定效果及非融合技术,为临床应用提供可行性证据。方法选择10只成年健康山羊作为实验对象,体重35~55 kg,羊龄10~24个月,随机分成A、B两组,每组各5只,经腰椎前外侧入路,行非融合技术人工椎间盘置换术,A、B组分别在术后3、6个月行腰椎正侧位的影像学检查,并分别在术后3、6个月取出包括假体在内的周围骨组织和软组织,常规制作标本后分别行病理、扫描电镜检查。通过腰椎影像学、病理及扫描电镜评价假体的固定效果、喷钛涂层骨长入及人工椎间盘的活动度。结果 10只山羊均建模成功,术后取出假体及周围组织的病理结果及电镜下可见假体喷钛涂层骨组织长入良好,人工椎间盘的钴铬钼合金、硅胶及喷钛涂层与周围组织相容性良好,腰椎X线片示假体位置良好,无松动,人工椎间盘有一定的活动度。结论非融合技术人工椎间盘的喷钛涂层骨长入良好,与椎体的固定效果可靠,材料的组织相容性好,具有非融合技术的效果。
文摘Discogenic low back pain is a serious medical and social problem, and accounts for 26%-42% of the patients with chronic low back pain. Recent studies found that the pathologic features of discs obtained from the patients with discogenic low back pain were the formation of the zones of vascularized granulation tissue, with extensive innervation in fissures extending from the outer part of the annulus into the nucleus pulposus. Studies suggested that the degeneration of the painful disc might originate from the injury and subsequent repair of annulus fibrosus. Growth factors such as basic fibroblast growth factor, transforming growth factor β1, and connective tissue growth factor, macrophages and mast cells might play a key role in the repair of the injured annulus fibrosus and subsequent disc degeneration. Although there exist controversies about the role of discography as a diagnostic test, provocation discography still is the only available means by which to identify a painful disc. A recent study has classified discogenic low back pain into two types that were annular disruption-induced low back pain and internal endplate disruption-induced low back pain, which have been fully supported by clinical and theoretical bases. Current treatment options for discogenic back pain range from medicinal anti-inflammation strategy to invasive procedures including spine fusion and recently spinal arthroplasty. However, these treatments are limited to relieving symptoms, with no attempt to restore the disc's structure. Recently, there has been a growing interest in developing strategies that aim to repair or regenerate the degenerated disc biologically.
文摘目的探讨经单侧行病变节段椎管减压、椎间植骨融合、单边椎弓根螺钉内固定治疗腰椎退变性疾病的临床疗效。方法我院2010年1月~2013年12月对35例腰椎退变性疾病采用经单侧减压、椎间植骨融合、单边椎弓根螺钉固定手术治疗。根据JOA评分法评估术后腰椎功能改善情况,采用视觉模拟评分（visual analog scale,VAS）评估术后疼痛缓解情况,腰椎正侧位X线片及CT扫描了解植骨融合情况。结果随访12~18个月,平均15个月。术前JOA评分（8.2±2.1）分,显著低于术后3个月（20.8±3.8）分（q=22.123,P〈0.05）和术后12个月（21.7±3.9）分（q=23.703,P〈0.05）;VAS评分术前（7.9±2.1）分,显著高于术后3个月（2.4±0.4）分（q=26.107,P〈0.05）和12个月（2.3±0.3）分（q=26.582,P〈0.05）;JOA评分和VAS评分随访期间无显著变化（P〉0.05）。1年后椎间植骨融合率100%,未发现椎弓根螺钉松动、断裂、拔钉等异常。结论经单侧减压、椎间植骨融合联合单边椎弓根螺钉内固定治疗腰椎退变性疾病疗效满意,可在合适病例中推广应用。
