• Journal of the Korean Society of Propulsion Engineers
• /
• v.7 no.4
• /
• pp.73-79
• /
• 2003

The tensile strength test and the analysis for the section of brazing were performed in the cases of materials used for combustion chamber of regeneratively cooled liquid rocket engine. BNi-2 and BNi-7 based on nickel were used for brazing as filler metal. The properties of material and filler metal were analyzed by tensile strength test and metal microscope for 12 specimens. The tensile-strength of brazing for chrome-copper alloy and other kinds of alloy was higher than that of chrome-zirconium-copper alloy and other kinds of alloy The tensile strength in the case of BNi-2 as filler metal was higher than that of BNi-7 because the wetting property of BNi-2 was better than that of BNi-7.

• Journal of Microbiology
• /
• v.45 no.1
• /
• pp.34-40
• /
• 2007

In budding yeast, G2/M transition is tightly correlated with bud morphogenesis regulated by Swel and septin that plays as a scaffold to recruits protein components. BNI5 isolated as a suppressor for septin defect is implicated in septin organization and cytokinesis. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we show that Bni5 phosphorylation is required for mitotic entry regulated by Swel pathway. Bni5 modification was evident from late mitosis to G1 phase, and CIP treatment in vitro of affinity-purified Bni5 removed the modification, indicative of phosphorylation on Bni5. The phosphorylation-deficient mutant of BNI5 (bni5-4A) was defective in both growth at semi-restrictive temperature and suppression of septin defect. Loss of Bni5 phosphorylation resulted in abnormal bud morphology and cell cycle delay at G2 phase, as evidenced by the formation of elongated cells with multinuclei. However, deletion of Swel completely eliminated the elongated-bud phenotypes of both bni5 deletion and bni5-4A mutants. These results suggest that the bud morphogenesis and mitotic entry are positively regulated by phosphorylation-dependent function of Bni5 which is under the control of Swel morphogenesis pathway.

• Journal of Microbiology
• /
• v.45 no.3
• /
• pp.227-233
• /
• 2007

In budding yeast, septin plays as a scaffold to recruits protein components and regulates crucial cellular events including bud site selection, bud morphogenesis, Cdc28 activation pathway, and cytokinesis. Phosphorylation of Bni5 isolated as a suppressor for septin defect is essential to Swe1-dependent regulation of bud morphogenesis and mitotic entry. The mechanism by which Bni5 regulates normal septin function is not completely understood. Here, we provide evidence that Bni5 phosphorylation is important for interaction with septin component Cdc11 and for timely delocalization from septin filament at late mitosis. Phosphorylation-deficient bni5-4A was synthetically lethal with $hof1{\Delta}$. bni5-4A cells had defective structure of septin ring and connected cell morphology, indicative of defects in cytokinesis. Two-hybrid analysis revealed that bni5-4A has a defect in direct interaction with Cdc11 and Cdc12. GFP-tagged bni5-4A was normally localized at mother-bud neck of budded cells before middle of mitosis. In contrast, at large-budded telophase cells, bni5-4A-GFP was defective in localization and disappeared from the neck approximately 2 min earlier than that of wild type, as evidenced by time-lapse analysis. Therefore, earlier delocalization of bni5-4A from septin filament is consistent with phosphorylation-dependent interaction with the septin component. These results suggest that timely de localization of Bni5 by phosphorylation is important for septin function and regulation of cytokinesis.

• The KSFM Journal of Fluid Machinery
• /
• v.19 no.3
• /
• pp.48-52
• /
• 2016

Microstructure and tensile strength of the vacuum brazed stainless steel(STS304) and WC-8 %Co were investigated. For brazing, the BNi-2, 3(A.W.S standard) were used as filler metals. It was found that metallic compounds of W-Ni were observed at the between WC metrix and brazed layer. Among these filler metals, the BNi-2 showed excellent wettability, but tensile strength was lower than BNi-3. The fracture of the brazed specimens with BNi-2 was occurred at the between WC metrix and brazed layer. The fracture of the brazed specimens with BNi-3 was occurred at the between WC metrix and brazed layer, and between brazed layer and stainless steel.

• Korean Journal of Materials Research
• /
• v.17 no.3
• /
• pp.142-146
• /
• 2007

Vacuum brazing method has been coming to an important process as one of the new fabricating techniques of metals and alloys. In this study, a vacuum brazing of SUS304 stainless steel with BNi-2 filler metal was carried out in $1{\times}10^{4}$ Torr of vacuum atmosphere. The formation of brittle intermetallic compounds in brazed joints between SUS304 stainless steel and BNi-2 filler metal is a major concern, since they considerably degrade the mechanical properties of joints. To obtain enough stable joining strength, it is necessary to understand the unique properties of brazing process with Ni-based filler metals containing boron. So, in this research we investigated the performance of SUS304/BNi-2 brazed system and the brazed joint properties were evaluated at room temperature by using tensile test. Metallurgical and fractographic analysis were used to characterize the microstructure, the mechanisms of brazing, and joint failure modes.

• Korean Journal of Materials Research
• /
• v.17 no.6
• /
• pp.342-346
• /
• 2007

Microstructure and tensile strength of the vacuum brazed stainless steel were investigated in this study. For vacuum brazing of the stainless steel 303 and 304, the BNi-2, 3, 4 and 7 were used as filler metals. Among these filler metals, the BNi-2 showed excellent wettability at $1050^{\circ}C$. Indeed, the brazed stainless steel using the BNi-2 showed the highest tensile strength (483 MPa) among all brazed specimens. This is attributed to degree of interfacial reaction between the filler metal and stainless steel. Brazed stainless steel with BNi-2, 3 filler metals showed almost elastic deformation followed by plastic yielding and strain hardening up to a peak stress. On the other hand, it is likely that the fracture of the brazed specimens with BNi-4, 7 was occurred in elastic range without plastic yielding up to a peak stress.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2005.11a
• /
• pp.49-51
• /
• 2005

• Korean Journal of Materials Research
• /
• v.17 no.3
• /
• pp.179-183
• /
• 2007

A plate heat exchanger (PHE) normally uses vacuum brazing technology for connecting plates and fins. However, the reliability of high temperature brazing, especially with nickel-based filler metals containing boron the formation of brittle intermetallic compounds (IMCs) in brazed joints is of major concern. since they considerably degrade the mechanical properties. This research was examined the vacuum brazing of commercially SUS304 stainless steel with BNi-2 (Ni-Cr-B-Si) filler metal, and discussed to determine the influence of brazing temperatures on the microstructure and mechanical strength of brazed joints. In the metallographic analysis it is observed that considerable large area of Cr-B intermetallic compound phases at the brazing layer and the brazing tensile strength is related to removal of this brittle phase greatly. The mechanical properties of brazing layer could be stabilized through increasing the brazing temperature over $100^{\circ}C$ more than melting temperature of filler metals, and diffusing enough the brittle intermetallic compound formed in the brazing layer to the base metal.

• Korean Journal of Materials Research
• /
• v.17 no.6
• /
• pp.293-297
• /
• 2007

Microstructure and tensile strength of the vacuum brazed stainless steel(STS303) and Cu were investigated. For brazing, the BNi-2, 3, 4, 6 and 7 (A.W.S standard) were used as filler metals. The Oxides such as $Cr_2O_3$ and $SiO_2$ were observed at brazed layers between STS303 and Cu matrix. Also, the intermetallic compounds of Cr-B and Ni-P were observed at brazed layers. Brazed STS303-Cu specimens with BNi-2, 3, 4 filler metals showed almost elastic deformation followed by plastic yielding and strain hardening up to a peak stress. On the other hand, it is likely that the fracture of the brazed specimens with BNi-6 and 7 was occurred in elastic range without plastic yielding up to a peak stress. Among these filler metals, the BNi-2 brazed at $1050^{\circ}C$ showed excellent wettability and the highest tensile strength (101.6MPa).

• Journal of Korean Neurosurgical Society
• /
• v.50 no.5
• /
• pp.446-452
• /
• 2011

Objective : We retrospectively investigated the long-term results of percutaneous radiofrequency thermocoagulation (RFT) using fluoroscopic image-guidance for treatment of trigeminal neuralgia. Methods : A total of 38 patients diagnosed and treated with RFT as an idiopathic trigeminal neuralgia were investigated. To minimize the risks related to conventional technique based on cutaneous landmarks, and to eliminate the need to frequent reposition of cannula, we adopted a technique of image-guided fluoroscopic cannulation of the foramen ovale. To minimize sensory complication following thermal lesion, our target response was a generation of a lesion with mild to moderate hypalgesia rather than dense hypalgesia. Results : The immediate pain-relief was achieved in all patients underwent RFT. With mean duration of follow-up of 38.2 months (range,12-72), 11 (28.9%) experienced recurrence of pain. The mean timing of recurrence was 26.1 months (range,12-46). A 42.7% recurrence rate was estimated by Kaplan-Meier analysis for the 38 patients at 46 months; 20.2% within 2 years, 29.1% within 3 years. In the long-term, 27 patients (71%) and 6 patients (15.8%) showed Barrow Neurological Institute (BNI) score I and BNI score II responses. Three (7.9%) patients was assessed as BNI score III, 2 patients (5.3%) showed BNI score IV response. As a complication, troublesome dysesthesia occurred in 3 of 38 patients (7.9%), however, there was no permanent cranial nerve palsy or morbidity. Conclusion : These results indicates that RFT under fluoroscopic image-guided cannulation of foramen ovale is a safe, effective, and reliable means of treating trigeminal neuralgia.