• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 추계 기술심포지움
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• pp.67-73
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• 2001

To investigate the relationships of solder joint characteristics with solder composition and A:V ratio (solder volume per pad area), Sn-37Pb and Sn-4.0Ag-0.5Cu solder balls with 330, 400, 450 and $457{\mu}{\textrm}{m}$ size were reflowed on same substrate. Sn-37Pb and Sn-4.0Ag-0.5Cu was reflowed at $220^{\circ}C$ and $240^{\circ}C$ respectively by IR-type soldering machine. As a result of reflowed solder- ball diameter(D) and height(H) measurement, D/H was decreased with solder ball size increment in range of 330~450 ${\mu}{\textrm}{m}$. But, D/H was increased in the solder joint for 457 ${\mu}{\textrm}{m}$ size, it was caused possibly by decrement of solder ball height increment compared with solder volume increment. As a result of shear and pull test, joint strength with A:V ratio was high. Joint strength of Sn-4.0Ag-0.5Cu was higher than Sn-37Pb. However, Sn-37Pb had more stable solder joint of small standard deviation. A thick and clean scallop type Ni-Cu-Sn intermetallic compound layer was formed in high A:V ratio and Sn-4.0Ag-0.5Cu solder joint interface.

• 대한안전경영과학회지
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• 제16권4호
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• pp.397-403
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• 2014

The objective of this study is to provide improved methodology based on the IPA method. One case studies are solved by the proposed method. this study present the method that give value to use SN(Signal-to-Noise) ratio in IPA. A case study of lecture satisfaction are solved by the proposed method and the existing method. Also, the result is compared with the existing method using Mean and the proposed method using SN ratio.

• 한국주조공학회지
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• 제27권2호
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• pp.72-76
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• 2007

Contact materials are widely used as electrical parts. Ag-Cd alloy has a good wear resistance and stable contact resistance. But the Cd exists as coarse oxide in alloy so it have an effect on mechanical properties badly. Moreover, the Cd is an injury material to environment. Nowadays, the use of Cd is strictly restricted. Because of these disadvantage, Ag-Sn-In alloy has been developed. In Ag-Sn-In alloy, the Sn : In ratio affects the internal oxidation properties, such as the formation of the oxide layer on the surface. In this work, we changed and optimized the Sn : In ratio variety for good internal oxidation properties. We have shown that a internal oxidation process did not fully completed when the Sn : In ratio is over 4 : 1 because of the Sn oxide layer at surface. The increase of In decelerates the formation of Sn oxide layer.

• 센서학회지
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• 제21권6호
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• pp.446-450
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• 2012

The important factors in sensors are sensitivity, selectivity, and response time. Oxide semiconductors are high sensitivity, fast response and the advantage of miniaturization. Zn-doped $SnO_2$ materials have been synthesized in order to improve the selectivity of the sensor. ZnO/$SnO_2$ crystals were prepared by a simple hydrothermal process and ultrasound pretreated hydrothermal process. ZnO/$SnO_2$ urchins were fabricated in the precursor solution with [$Zn^{2+}$]:[$Sn^{4+}$] ratio of 1:5 and rod structures were fabricated ratio of 1:1 and 1:3. Surface area ratio was increased by increasing the ratio of [$Sn^{4+}$]. The sensitivity of sensors were highest at the [$Zn^{2+}$]:[$Sn^{4+}$] ratio of 1:5 in ethanol, acetaldehyde, toluene, and nitric oxide.

• Journal of the Korean Data and Information Science Society
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• 제12권1호
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• pp.11-18
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• 2001

다구찌가 제안한 파라미터 설계는 제품설계나 공정설계 단계에서 품질특성치의 수행변동(performance variation)을 줄이는데 있다. 파라미터 설계에서 품질평균 근처에서 품질의 변동을 줄일 수 있는 최적조건을 찾는데 있어서 신호대 잡음비(Signal-to-noise ratio; SN비)라는 수행측도(performance measure)를 사용하였다. 그러나 많은 통계학자들은 SN비를 이용한 다구찌 분석 기법을 비판한다. 본 논문에서는 파라미터 설계를 위한 최적조건을 찾는데 있어서 SN비를 사용하지 않는 보다 실질적인 최적방안을 제안한다.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 1998년도 The 12th Asia Quality Management Symposium* Total Quality Management for Restoring Competitiveness
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• pp.610-621
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• 1998

In parameter design introduced by Taguchi, we analyze a signal-to-noise(SN) ratio. The SN ratio is a function of the expected loss due to the variation of quality characteristic. In this paper, an easy way for developing SN ratios is presented, which can be used to several quality characteristics simultaneously in parameter design. To develop such multivariate SN ratios, the transformation method of the expected loss and combining techniques are employed. And the analysis of real empirical data for an application of the proposed method is also presented.

• 품질경영학회지
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• 제21권1호
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• pp.96-107
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• 1993

In parameter design Taguchi analyzed a statistic which he called signal-to-noise(SN) ratio by using the experimental design technique. However he gave no justification for using SN ratios in the optimization procedure of parameter design. In this paper we discuss the validity of such SN ratios as proper statistics to be analyzed in parameter design. Moreover, using the real empirical data we examine the appropriateness of SN ratios, and we explain how transformation technique can be applied in parameter design as an alternative method of analysis.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.414-419
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• 2012

In this paper, the properties of SnZnO films obtained from solution process with different component fractions were compared. The thermal behavior of the SnZnO solutions showed only a slight change according to the component fraction change. However, the definite changes were revealed at the structural properties of the SnZnO films. With diverse analyses, the origin of the changes was proved to the influence of phase change from $SnO_2$ to ZnO in SnZnO lattice. With the $SnO_2$-phase-dominant SnZnO, the highest field effect mobility and on/off ratio of about 8.6 $cm^2/Vs$ and $2{\times}10^8$ were achieved, respectively.

• 한국결정성장학회지
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• 제4권3호
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• pp.294-305
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• 1994

초음파 분무법에 의한 $SnO_2(:F)$박막의 제막시 DBDA와 $SnCl_4.5H_2O$를 출발물질로 사용하은 경우 제막조건이 전기적, 광학적 그리고 표면형상 드의 특성에 미치는 영향에 대해 조사하였다. 박막의 비저항은 출발물질에 관계없이 용액내의 F/Sn의 비가 0.6일 때까지는 급격히 증가하였으며, $SnO_2.5H_2O$를 출발물질로 사용한 경우 DBDA의 경우보다 낮았다. 용액내의 F/Sn의 비가 1일 때 출발물질로서, $SnO_2.5H_2O$과 DBDA를 사용한 경우 광투과율은 각각 83%와 85%로서 DBDA 사용한 경우가 다소 높았다.

• 대한방사선기술학회지:방사선기술과학
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• 제26권1호
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• pp.45-50
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• 2003

투시 조영 촬영시 사용되는 방호복의 차폐효율 증가와 경량화는 오랜 시간 연구 대상이 되었다. 이러한 방호복의 질적 향상을 위하여 연구한 결과는 다음과 같다. Apron의 규격인 납당량 0.25 mm에 해당하는 투과선량률은 5.2%로 나타났으며, 시료 Sn, Ni, Ti, Cu의 방사선 차폐 효율은 Sn이 가장 놓게 나타났다. 증착시료 Sn + Pb와 Pb + Sn는 각각 Sn 0.18 mm와 Pb 0.1 mm, Pb 0.1 mm와 Sn 0.36 mm에서 apron의 규격인 납 0.25 mm 두께로 나타났다. 증착시료 Sn+Pb는 Apron의 규격인 0.25 mm 두께보다 차폐효율이 높고, 면적당 무게가 가벼워 방호복 물질로 적합한 적으로 사료된다.