• 제목/요약/키워드: school bonding

검색결과 893건 처리시간 0.023초

환경변인 및 부모-자녀 유대관계가 농촌 고등학생들의 자아분화에 미치는 영향 (Effect of Environment and Parent-Bodning Relationship on rural high School students' Differentiation of Self)

  • 백양희
    • 대한가정학회지
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    • 제35권6호
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    • pp.71-86
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    • 1997
  • The purpose of this study was to investigate the effect of parent-bonding patterns & environmental variables on rural high school students' self-differentiationf. The subjects were 600 rural high school students in the 2nd grade. The rural high school students' self-differentiation, according to parent-bonding style & environmental variables were researched with DOSS(Differentiation of self Scale) PBI(Parent-bonding Instrument) & environmental Scale. The data were analyzed by frequency & Reliability, ANOVA (scheffe'test) & Regression analysis of SPSS PC+ program. The main results were as follows. First, In P-B patterns generally frequencies of mother's care were higher than father's But in overprotection frequencies of father's were higher. Degree of rural highschool students' self-differentiation was on the level of 2.84 Second, According to parent-bonding patterns, the difference of self-differentiation were as follow. In P-B patters, father and mother on each level of P<.001 brought differences in the self-differentiation of the 4 sub-divisions Third, In short the effect on self-differentiation showed that in family environmental variables, parent's scolding, gender, family atmosphere & health conditions are crucial variables in self-differentiation and in P-B patterns, father's overprotection, mother's care, father's care are all influential on self-differentiation.

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생활치 미백제가 상아질 접착에 미치는 영향 (Effect of Vital Tooth Bleaching Agent on Dentin Bonding)

  • 정나영;진명욱;김영경;김성교
    • Restorative Dentistry and Endodontics
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    • 제31권2호
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    • pp.79-85
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    • 2006
  • 생활치 미백제와 알콜 전처리 과정이 상아질 접착에 미치는 영향을 평가하고자 발거치 55개의 치관부 협측 상아질면에서 $Opalescence^{(R)}$(Ultradent사 미국)로 미백처리 후 즉시 $One-step^{(R)}$ 상아질 접착제(Bisco사, 미국)를 전 처치한 $Z-250^{(R)}$ 복합레진(3M-ESPE사, 미국) 접착군, 미백처리 2주후 레진 접착군, 미백처리 후 70% 에탄올 처리군, 그리고 미백처리하지 않은 대조군으로 나누어 실험한 다음 전단접착강도를 측정하고 95% 유의수준에서 일원변량분석법으로 통계분석 하였다. 생활치 미백제가 상아질 접착력을 현저히 감소시켰다. 미백처리 2주 후 레진 접착군은 미백처리하지 않은 대조군과 유의한 차이가 나타나지 않았으며 70% 에탄을 처리군은 미백처리하지 않은 대조군보다는 접착력이 낮았으나, 미백처리 2주 후 레진 접착군과는 차이가 없고 즉시 접착군보다는 높은 접착강도를 나타내었다. 따라서 임상에서 치아미백 후 즉시 레진수복을 할 경우, 에탄올로 전처리하면 상아질에서 레진 접착력을 회복할 수 있을 것으로 사료된다.

Effects of Stock Characteristics on Paper Bulk

  • Lee, Jin-Ho;Park, Jong-Moon
    • 한국펄프종이공학회:학술대회논문집
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    • 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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    • pp.423-426
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    • 2006
  • Paper has fibers and fines network structure and it is strongly affected by interface bonding between fibers. Depending on the inter-fiber bonding, paper bulk is determined. Fines play an important roll in Campbell and consolidation effect through wet pressing and drying operations. Refined Sw-BKP, Hw-BKP and BCTMP fines were used to investigate the fines effect. Wet-web strength, breaking length, scattering coefficient, and hydrodynamic specific volume were measured. According to the result of experiments, chemical and morphological compositions of fines do not strongly affect to wet-web forming, but strongly affect to drying operations which form hydrogen bonding among fiber-fines-fiber matrixes. Paper bulk should be controlled by the extent of hydrogen bonding between fibers during drying operations.

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상아질 접착에 대한 matrix metalloproteinase (MMP)의 영향과 이를 극복하기 위한 전략 (Effects of matrix metallproteinases on dentin bonding and strategies to increase durability of dentin adhesion)

  • 이정현;장주혜;손호현
    • Restorative Dentistry and Endodontics
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    • 제37권1호
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    • pp.2-8
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    • 2012
  • The limited durability of resin-dentin bonds severely compromises the longevity of composite resin restorations. Resin-dentin bond degradation might occur via degradation of water-rich and resin sparse collagen matrices by host-derived matrix metalloproteinases (MMPs). This review article provides overview of current knowledge of the role of MMPs in dentin matrix degradation and four experimental strategies for extending the longevity of resin-dentin bonds. They include: (1) the use of broadspectrum inhibitors of MMPs, (2) the use of cross-linking agents for silencing the activities of MMPs, (3) ethanol wet-bonding with hydrophobic resin, (4) biomimetic remineralization of water-filled collagen matrix. A combination of these strategies will be able to overcome the limitations in resin-dentin adhesion.

기판단위 밀봉 패키징을 위한 내압 동공열의 설계 및 강도 평가 (Design and Strength Evaluation of an Anodically Bonded Pressurized Cavity Array for Wafer-Level MEMS Packaging)

  • 강태구;조영호
    • 대한기계학회논문집A
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    • 제25권1호
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    • pp.11-15
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    • 2001
  • We present the design and strength evaluation of an anodically bonded pressurized cavity array, based on the energy release rate measured from the anodically bonded plates of two dissimilar materials. From a theoretical analysis, a simple fracture mechanics model of the pressurized cavity array has been developed. The energy release rate (ERR) of the bonded cavity with an infinite bonding length has been derived in terms of cavity pressure, cavity size, bonding length, plate size and material properties. The ERR with a finite bonding length has been evaluated from the finite element analysis performed for varying cavity and plate sizes. It is found that, for an inter-cavity bonding length greater than the half of the cavity length, the bonding strength of cavity array approaches to that of the infinite plate. For a shorter bonding length, however, the bonding strength of the cavity array is monotonically decreased with the ratio of the bonding length to the cavity length. The critical ERR of 6.21J/㎡ has been measured from anodically bonded silicon-glass plates. A set of critical pressure curves has been generated for varying cavity array sizes, and a design method of the pressurized cavity array has been developed for the failure-free wafer-level packaging of MEMS devices.

자가부식형 상아질 접착제와 상아질과의 전단결합강도 비교 (Comparison of the shear bond strength of self-etching dentin bonding agents to dentin)

  • 노수정;김부섭;정인성
    • 대한치과기공학회지
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    • 제29권2호
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    • pp.141-150
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    • 2007
  • The purpose of this study was to ascertain the bonding durability of self-etching dentin bonding agents to dentin by means of shear bonding strength. Several acid-etching dentin bonding system (ESPE Z100) and self-etching dentin bonding systems (DEN-FIL, GRADIA DIRET) were used. The occlusion surface of human molars were ground flat to expose dentin and treated with the etch bonding system according to manufactures instruction and followed by composite resin application. After 24hours of storage at 37$^{\circ}C$, the shear bonding strength of the specimens was measured in a universal testing machine with a 1mm/min crosshead speed. An one-way analysis of variance and the scheffe test were performed to identify significant differences (p<0.05). The bonded interfacial surfaces and treated dentin surfaces were examined using a SEM. Through the analysis of shear bond strength data and micro-structures of dentin-resin interfaces, following results are obtained. In dentin group, the shear bond strength of DEN-FIL showed statistical superiority in comparison to the other groups and followed by ESPE Z100 and GRADIA DIRECT (p<0.05).

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Adhesive bonding using thick polymer film of SU-8 photoresist for wafer level package

  • Na, Kyoung-Hwan;Kim, Ill-Hwan;Lee, Eun-Sung;Kim, Hyeon-Cheol;Chun, Kuk-Jin
    • 센서학회지
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    • 제16권5호
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    • pp.325-330
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    • 2007
  • For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, size and shape of pattern and thickness of spacer can be easily controlled. This paper presents polymer bonding using thick, uniform and patterned spacing layer of SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and it is cured at $95^{\circ}C$ and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with $400{\mu}m$ of thickness and 3.25 % of uniformity through single coating. Also we improved tensile strength from hundreds kPa to maximum 9.43 MPa through depositing gold layer onto glass substrate.

Effect of universal adhesive pretreatments on the bond strength durability of conventional and adhesive resin cements to zirconia ceramic

  • Tae-Yub Kwon;Seung-Hee Han;Du-Hyeong Lee;Jin-Woo Park;Young Kyung Kim
    • The Journal of Advanced Prosthodontics
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    • 제16권2호
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    • pp.105-114
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    • 2024
  • PURPOSE. This study aimed to evaluate the effect of pretreatment of three different universal adhesives (Single Bond Universal [SBU], All-Bond Universal [ABU], and Prime&Bond universal [PBU]) on the bonding durability of an adhesive (Panavia F 2.0, PF) and a conventional (Duo-Link, DL) resin cements to air-abraded zirconia. MATERIALS AND METHODS. Rectangular-shaped zirconia specimens were prepared. The chemical composition and surface energy parameters of the materials were studied by Fourier transform infrared spectroscopy and contact angle measurement, respectively. To evaluate resin bonding to the zirconia, all the bonding specimens were immersed in water for 24 h and the specimens to be aged were additionally thermocycled 10000 times before the shear bond strength (SBS) test. RESULTS. The materials showed different surface energy parameters, including the degree of hydrophilicity/hydrophobicity. While the DL/CON (no pretreatment) showed the lowest SBS and a significant decrease in the value after thermocycling (P < .001), the PF/CON obtained a higher SBS value than the DL/CON (P < .001) and no decrease even after thermocycling (P = .839). When the universal adhesives were used with DL, their SBS values were higher than the CON (P < .05), but the trend was adhesive-specific. In conjunction with PF, the PF/SBU produced the highest SBS followed by the PF/ABU (P = .002), showing no significant decrease after thermocycling (P > .05). The initial SBS of the PF/PBU was similar to the PF/CON (P = .999), but the value decreased after thermocycling (P < .001). CONCLUSION. The universal adhesive pretreatment did not necessarily show a synergistic effect on the bonding performance of an adhesive resin cement, whereas the pretreatment was beneficial to bond strength and durability of a conventional resin cement.

다구찌법을 이용한 IR 레이저 Flip-chip 접합공정 최적화 연구 (A Study on the Optimization of IR Laser Flip-chip Bonding Process Using Taguchi Methods)

  • 송춘삼;지현식;김주한;김종형;안효석
    • Journal of Welding and Joining
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    • 제26권3호
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    • pp.30-36
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    • 2008
  • A flip-chip bonding system using IR laser with a wavelength of 1064 nm was developed and associated process parameters were analyzed using Taguchi methods. An infrared laser beam is designed to transmit through a silicon chip and used for transferring laser energy directly to micro-bumps. This process has several advantages: minimized heat affect zone, fast bonding and good reliability in the microchip bonding interface. Approximately 50 % of the irradiated energy can be directly used for bonding the solder bumps with a few seconds of bonding time. A flip-chip with 120 solder bumps was used for this experiment and the composition of the solder bump was Sn3.0Ag0.5Cu. The main processing parameters for IR laser flip-chip bonding were laser power, scanning speed, a spot size and UBM thickness. Taguchi methods were applied for optimizing these four main processing parameters. The optimized bump shape and its shear force were modeled and the experimental results were compared with them. The analysis results indicate that the bump shape and its shear force are dominantly influenced by laser power and scanning speed over a laser spot size. In addition, various effects of processing parameters for IR laser flip-chip bonding are presented and discussed.

Effects of different primers on indirect orthodontic bonding: Shear bond strength, color change, and enamel roughness

  • Tavares, Mirella Lemos Queiroz;Elias, Carlos Nelson;Nojima, Lincoln Issamu
    • 대한치과교정학회지
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    • 제48권4호
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    • pp.245-252
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    • 2018
  • Objective: We aimed to perform in-vitro evaluation to compare 1) shear bond strength (SBS), adhesive remnant index (ARI), and color change between self-etched and acid-etched primers; 2) the SBS, ARI and color change between direct and indirect bonding; and 3) the enamel roughness (ER) between 12-blade bur and aluminum oxide polisher debonding methods. Methods: Seventy bovine incisors were distributed in seven groups: control (no bonding), direct (DTBX), and 5 indirect bonding (ITBX, IZ350, ISONDHI, ISEP, and ITBXp). Transbond XT Primer was used in the DTBX, ITBX, and ITBXp groups, flow resin Z350 in the IZ350 group, Sondhi in the ISONDHI group, and SEP primer in the ISEP group. SBS, ARI, and ER were evaluated. The adhesive remnant was removed using a low-speed tungsten bur in all groups except the ITBXp, in which an aluminum oxide polisher was used. After coffee staining, color evaluations were performed using a spectrophotometer immediately after staining and prior to bonding. Results: ISONDHI and ISEP showed significantly lower SBS (p < 0.01). DTBX had a greater number of teeth with all the adhesive on the enamel (70%), compared with the indirect bonding groups (0-30%). The ER in the ITBX and ITBXp groups was found to be greater because of both clean-up techniques used. Conclusions: Direct and indirect bonding have similar results and all the primers used show satisfactory adhesion strength. Use of burs and polishers increases the ER, but polishers ensure greater integrity of the initial roughness. Resin tags do not change the color of the teeth.