68 research outputs found
Mechanical properties of intermetallic compounds on lead-free solder by moir? techniques
No full textSimultaneously determining Young's modulus, coefficient of thermal expansion, Poisson ratio and thickness of thin films on silicon wafer
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A highly efficient thermally controlled loss-tunable long-period fiber grating on corrugated metal substrate
No full textWe demonstrate a new approach for fabricating a
compact loss-tunable long-period fiber grating (LPFG) by gluing a fiber onto a corrugated metal substrate filled with ultraviolet- cured epoxy. The strain caused by the difference in thermal expansion among the adhesive, the substrate, & the silica fiber induces a periodic microbending along the fiber when the device temperature is changed. The LPFG has an initial flat spectrum at room temperature. With 35 grating periods, a tuning range of 21 dB is achieved through core–cladding coupling for a temperature change from room temperature to 4 C. A theoretical model is presented to explain the high tuning efficiency & the operating mechanisms of the device
Physiological patellofemoral crepitus in knee joint disorders
No full text Vibration waves produced by the knee joint during extension-flexion may be recorded by vibration arthrometry. When the speed of this motion is less than 5 degrees persecond, the vibration produced by the patella is referred to as physiological patellofemoral crepitus (PPC), which reflects the integrity of artecular cartilage. PPC signals were recorded prior to scheduled arthroscopic examinations or operations in 17 patients whose patellofemoral jointd cautilage was found subsequently to be normal, and in 25 patients (36 knee joints) who underwent arthroscopic debridement, osteotomy, or total knee replacement due to degenerative osteosrthritis. The PPC signals of five normal young adults (10 knees) without any knee problems were also recorded as a control group. The root mean square (RMS) values of the PPC signals of the control group, the group with knee injuries, and the osteoarthritic patients were 0. 69, 0.17, and 0.04 m/sec 2, respectively. Differences among these groups were statistically significant(P<0.001). When the time domain pattern and RMS value of the preoperative PPC dignals were studied and compared with the couuesponding pathological findings in joint cartilage, as noted in the surgical findings, three types of PPC signals of the osteoarthritic knees could be identified and each indicated pathological changes of a different. When the 53 PPC signals were reviewed according to these criteria, the accuracy , sensitivity, and specificity of the diagnosis of osteoarthritic change of the patellofemoral joint by vibration arthrometry was fornd to be 94.3% , 97.2%, and 88.2 %, respectively. Based on these results, the detection of PPC by vibration arthrometry may be considered a reliable and non- invasive diagnostic procedure for the evaluation of patellofemoral joint cartilage integrity.#0622
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