http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
“Free Hand” or Wire Guide: To the Editor
Nirmal Kumar Sinha,Amit Bhardwaj 대한정형외과학회 2019 Clinics in Orthopedic Surgery Vol.11 No.4
We read with interest the article “Learning curve of internal fixation for nondisplaced femoral neck fractures: a cumulative sum analysis.”1) Stability of fracture depends upon the parallelity of the cancellous screws that fixes the fractured neck of femur. It is not easy to insert guidewire at the right position and in parallel orientation.2) We all know from our experience that there is a learning curve involved in the passing of parallel screws, much more so if it is done “free hand.” Even a parallel wire guide requires passing of a central guide wire in exact central position. The paper does not mention if any wire guide was used during fixation. We are curious to know about the cause of significant difference of operating time between the early and late experience group (52.2 ± 15.2 vs. 38.4 ± 13.0 minutes). Which part of the surgical procedure required more time in the early group and has learning improved the operating time in the late group?
Nickel doped PZT ceramics by a spray dried-PVA assisted method
S.K. Sinha,Amit Kumar Sinha,P. Kour,P.K. Barhai 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.1
Ferroelectric thin material of PZT modified with Ni 2+, with a Zr/Ti molar ratio 54/46 was prepared by spray drying the nitrate solution of lead, zirconium ,titanium and nickel in a stoichiometric ratio followed by stirring at 80 oC for 36 hours in 3% v/v PVA. The gel prepared by the PVA method was then calcined at 550 oC. Tetragonal perovskite type phases were identified as being present in the calcined powder. The remanent polarization (Pr) and the coercive field (Ec) were found to be 5.1 μCcm−2 and 46.2 KV/cm, respectively. The d33 value in PZT was found to be 192 × 10−12 C/N at 33 KV/cm at 1.5 atomic percent dopant concentration. SEM micrographs showed the grain size in the range of 0.5 μm. In conclusion, Ni 2+ incorporation in a PZT material contributes to the polarizibility and the spray dried PVA method slightly lowers the Pr and increases the Ec when compared to the sol.gel technique or magnetron sputtering technique.