Twist-Off Testing of Solder Joint Interconnections

1989 ◽  
Vol 111 (3) ◽  
pp. 165-171 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Quality Control ◽  
Solder Joint ◽  
Experimental Method ◽  
Comparative Evaluation ◽  
Solder Joints ◽  
Attractive Alternative ◽  
Shearing Force ◽  
Shearing Strength ◽  
The Relationship

Twist-off testing of solder joint interconnections is regarded by many reliability engineers in the microelectronic industry as an attractive alternative to shear-off testing. In this paper we briefly discuss the merits and shortcomings of both techniques and determine the relationship between the ultimate torque and the ultimate shearing force. We also suggest a simple experimental method for the evaluation of the shearing strength of solder joints on the basis of twist-off testing. It should be emphasized that such testing can be used not only for a tentative comparative evaluation of different interconnections but as a quality control vehicle as well.

Comparison of In-the-Ear and Over-the-Ear Hearing Aid Fittings

1986 ◽  
Vol 51 (4) ◽  
pp. 362-369 ◽  
Author(s):  
Donna M. Risberg ◽  
Robyn M. Cox
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Comparative Evaluation ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Aid Fitting ◽  
The Difference ◽  
Functional Gain ◽  
The Relationship

A custom in-the-ear (ITE) hearing aid fitting was compared to two over-the-ear (OTE) hearing aid fittings for each of 9 subjects with mild to moderately severe hearing losses. Speech intelligibility via the three instruments was compared using the Speech Intelligibility Rating (SIR) test. The relationship between functional gain and coupler gain was compared for the ITE and the higher rated OTE instruments. The difference in input received at the microphone locations of the two types of hearing aids was measured for 10 different subjects and compared to the functional gain data. It was concluded that (a) for persons with mild to moderately severe hearing losses, appropriately adjusted custom ITE fittings typically yield speech intelligibility that is equal to the better OTE fitting identified in a comparative evaluation; and (b) gain prescriptions for ITE hearing aids should be adjusted to account for the high-frequency emphasis associated with in-the-concha microphone placement.

“I stay at work for you, you stay at home for us.” Does this Covid-19 campaign work for the youth in Asia?

2020 ◽  
Vol 8 (2) ◽  
pp. 161-175
Author(s):  
Jappy Fanggidae ◽  
Ridolof Batilmurik ◽  
Pieter Samadara
Keyword(s):  
Experimental Method ◽  
Social Distancing ◽  
Asian Context ◽  
The Relationship ◽  
At Home

This study investigated the relationship between guilt appeal and compliance with social distancing measures. We proposed that the relationship is double mediated by empathy and responsibility for the unfortunate people who have suffered from COVID-19. This research is novel to an extent as an experimental method is used in the Asian context. The results exhibited that guilt positively affected compliance with social distancing measures. The respondents were directly or indirectly compliant due to the emotions of empathy and responsibility. The theoretical and practical contributions of this study were presented.

Hope and Necessity

2019 ◽  
Vol 11 (3) ◽  
pp. 49
Author(s):  
Sarah Pawlett-Jackson
Keyword(s):  
Comparative Evaluation ◽  
Final Word ◽  
Way Of Thinking ◽  
The Relationship

In this paper I offer a comparative evaluation of two types of “fundamental hope”, drawn from the writing of Rebecca Solnit and Rowan Williams respectively. Arguments can be found in both, I argue, for the foundations of a dispositional existential hope. Examining and comparing the differences between these accounts, I focus on the consequences implied for hope’s freedom and stability. I focus specifically on how these two accounts differ in their claims about the relationship between hope and (two types of) necessity. I argue that both Solnit and Williams base their claims for warranted fundamental hope on a sense of how reality is structured, taking this structure to provide grounds for a basic existential orientation that absolute despair is never the final word. For Solnit this structure is one of unpredictability; for Williams it is one of excess. While this investigation finds both accounts of fundamental hope to be plausible and insightful, I argue that Williams’s account is ultimately more satisfying on the grounds that it offers a realistic way of thinking about a hope necessitated by what it is responsive to, and more substantial in responding to what is necessary.

Predictive Failure Analysis of Solder Joints with Simultaneous High Speed EBSD and EDS

2018 ◽  
Author(s):  
J. Lindsay ◽  
P. Trimby ◽  
J. Goulden ◽  
S. McCracken ◽  
R. Andrews
Keyword(s):  
High Speed ◽  
Solder Joints ◽  
Phase Distribution ◽  
Bond Failure ◽  
Microstructural Parameters ◽  
Snpb Solder ◽  
Grain Orientations ◽  
Accelerated Thermal Cycling ◽  
The Relationship ◽  
Opening Up

Abstract The results presented here show how high-speed simultaneous EBSD and EDS can be used to characterize the essential microstructural parameters in SnPb solder joints with high resolution and precision. Analyses of both intact and failed solder joints have been carried out. Regions of strain localization that are not apparent from the Sn and Pb phase distribution are identified in the intact bond, providing key insights into the mechanism of potential bond failure. In addition, EBSD provides a wealth of quantitative detail such as the relationship between parent Sn grain orientations and Pb coarsening, the morphology and distribution of IMCs on a sub-micron scale and accurate grain size information for all phases within the joint. Such analyses enable a better understanding of the microstructural developments leading up to failure, opening up the possibility of improved accelerated thermal cycling (ATC) testing and better quality control.

scholarly journals Study on the Reliability of Sn–Bi Composite Solder Pastes with Thermosetting Epoxy under Thermal Cycling and Humidity Treatment

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 733
Author(s):  
Lu Liu ◽  
Songbai Xue ◽  
Ruiyang Ni ◽  
Peng Zhang ◽  
Jie Wu
Keyword(s):  
Solder Joint ◽  
Thermal Cycling ◽  
Composite Solder ◽  
Solder Joints ◽  
Solder Paste ◽  
Epoxy System ◽  
Mechanical Reinforcement ◽  
Microstructure Observation ◽  
Temperature And Humidity ◽  
Thermosetting Epoxy

In this study, a Sn–Bi composite solder paste with thermosetting epoxy (TSEP Sn–Bi) was prepared by mixing Sn–Bi solder powder, flux, and epoxy system. The melting characteristics of the Sn–Bi solder alloy and the curing reaction of the epoxy system were measured by differential scanning calorimeter (DSC). A reflow profile was optimized based on the Sn–Bi reflow profile, and the Organic Solderability Preservative (OSP) Cu pad mounted 0603 chip resistor was chosen to reflow soldering and to prepare samples of the corresponding joint. The high temperature and humidity reliability of the solder joints at 85 °C/85% RH (Relative Humidity) for 1000 h and the thermal cycle reliability of the solder joints from −40 °C to 125 °C for 1000 cycles were investigated. Compared to the Sn–Bi solder joint, the TSEP Sn–Bi solder joints had increased reliability. The microstructure observation shows that the epoxy resin curing process did not affect the transformation of the microstructure. The shear force of the TSEP Sn–Bi solder joints after 1000 cycles of thermal cycling test was 1.23–1.35 times higher than the Sn–Bi solder joint and after 1000 h of temperature and humidity tests was 1.14–1.27 times higher than the Sn–Bi solder joint. The fracture analysis indicated that the cured cover layer could still have a mechanical reinforcement to the TSEP Sn–Bi solder joints after these reliability tests.

scholarly journals Development and Validation of a GMP-Compliant High-Pressure Liquid Chromatography Method for the Determination of the Chemical and Radiochemical Purity of [18F]PSMA-1007, a PET Tracer for the Imaging of Prostate Cancer

2021 ◽  
Vol 14 (3) ◽  
pp. 188
Author(s):  
Ines Katzschmann ◽  
Heike Marx ◽  
Klaus Kopka ◽  
Ute Hennrich
Keyword(s):  
Prostate Cancer ◽  
Quality Control ◽  
Radiochemical Purity ◽  
Control Method ◽  
Solid Phase ◽  
Hplc Method ◽  
Attractive Alternative ◽  
Chromatography Method ◽  
Pet Tracer

For the PET imaging of prostate cancer, radiotracers targeting the prostate-specific membrane antigen (PSMA) are nowadays used in clinical practice. [18F]PSMA-1007, a radiopharmaceutical labeled with fluorine-18, has excellent properties for the detection of prostate cancer. Essential for the human use of a radiotracer is its production and quality control under GMP-compliance. For this purpose, all analytical methods have to be validated. [18F]PSMA-1007 is easily radiosynthesized in a one-step procedure and isolated using solid phase extraction (SPE) cartridges followed by formulation of a buffered injection solution and for the determination of its chemical and radiochemical purity a robust, fast and reliable quality control method using radio-HPLC is necessary. After development and optimizations overcoming problems in reproducibility, the here described radio-HPLC method fulfills all acceptance criteria—for e.g., specificity, linearity, and accuracy—and is therefore well suited for the routine quality control of [18F]PSMA-1007 before release of the radiopharmaceutical. Recently a European Pharmacopeia monograph for [18F]PSMA-1007 was published suggesting a different radio-HPLC method for the determination of its chemical and radiochemical purity. Since the here described method has certain advantages, not least of all easier technical implementation, it can be an attractive alternative to the monograph method. The here described method was successfully validated on several radio-HPLC systems in our lab and used for the analysis of more than 60 batches of [18F]PSMA-1007. Using this method, the chemical and radiochemical purity of [18F]PSMA-1007 can routinely be evaluated assuring patient safety.

scholarly journals Single, context-specific glycans can target misfolded glycoproteins for ER-associated degradation

2005 ◽  
Vol 169 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Eric D. Spear ◽  
Davis T.W. Ng
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Secretory Protein ◽  
Carboxypeptidase Y ◽  
Er Quality Control ◽  
Systematic Analysis ◽  
Proteinase A ◽  
Context Specific ◽  
The Relationship ◽  
Erad Pathway

The endoplasmic reticulum (ER) maintains an environment essential for secretory protein folding. Consequently, the premature transport of polypeptides would be harmful to the cell. To avert this scenario, mechanisms collectively termed “ER quality control” prevent the transport of nascent polypeptides until they properly fold. Irreversibly misfolded molecules are sorted for disposal by the ER-associated degradation (ERAD) pathway. To better understand the relationship between quality control and ERAD, we studied a new misfolded variant of carboxypeptidase Y (CPY). The molecule was recognized and retained by ER quality control but failed to enter the ERAD pathway. Systematic analysis revealed that a single, specific N-linked glycan of CPY was required for sorting into the pathway. The determinant is dependent on the putative lectin-like receptor Htm1/Mnl1p. The discovery of a similar signal in misfolded proteinase A supported the generality of the mechanism. These studies show that specific signals embedded in glycoproteins can direct their degradation if they fail to fold.

The Consequences of not Acting on Personally and Socially Important Value-Expressive Behaviours on Hedonic and Eudaimonic Wellbeing

2021 ◽  
Author(s):  
◽  
Megan Chrystal
Keyword(s):  
Experimental Method ◽  
Social Desirability ◽  
Personal Values ◽  
Personal Value ◽  
The Relationship ◽  
Eudaimonic Wellbeing

<p>Wellbeing is thought to decrease when one’s actions do not align with one’s values. This study refined a previous experimental method to investigate how perceived failure to live up to expectations of value-expressive behaviours may affect eudaimonic and hedonic wellbeing. One hundred and ninety-nine students considered their own past value-expressive behaviours in a survey designed to induce a discrepancy or “gap” between reported and ideal behaviour. We tested whether the importance of value-expressive behaviours—and whether this importance was based on personal or social ideals—would affect the perception of behavioural discrepancies and wellbeing. Results showed that being asked about more important behaviours predicted a greater perceived behavioural gap and less hedonic wellbeing. Whether this importance was based on personal values or social desirability did not differentially predict perceived behavioural gap or wellbeing, challenging the focus that some therapy models place on personal value expression to improve wellbeing. The perceived behavioural gap did not mediate a relationship between experimental condition and wellbeing, suggesting that other variables may play a role in the relationship between values, behaviour, and wellbeing. Further exploratory tests, limitations, and theoretical implications are discussed.</p>

Effect of intermetallic compound layer thickness on the shear strength of 1206 chip resistor solder joint

2015 ◽  
Vol 27 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Peter K. Bernasko ◽  
Sabuj Mallik ◽  
G. Takyi
Keyword(s):  
Shear Strength ◽  
Intermetallic Compound ◽  
Solder Joint ◽  
Layer Thickness ◽  
Solder Joints ◽  
Ageing Time ◽  
Circuit Board ◽  
Intermetallic Compound Layer ◽  
Content Type ◽  
Surface Mount

Purpose – The purpose of this paper is to study the effect of intermetallic compound (IMC) layer thickness on the shear strength of surface-mount component 1206 chip resistor solder joints. Design/methodology/approach – To evaluate the shear strength and IMC thickness of the 1206 chip resistor solder joints, the test vehicles were conventionally reflowed for 480 seconds at a peak temperature of 240°C at different isothermal ageing times of 100, 200 and 300 hours. A cross-sectional study was conducted on the reflowed and aged 1206 chip resistor solder joints. The shear strength of the solder joints aged at 100, 200 and 300 hours was measured using a shear tester (Dage-4000PXY bond tester). Findings – It was found that the growth of IMC layer thickness increases as the ageing time increases at a constant temperature of 175°C, which resulted in a reduction of solder joint strength due to its brittle nature. It was also found that the shear strength of the reflowed 1206 chip resistor solder joint was higher than the aged joints. Moreover, it was revealed that the shear strength of the 1206 resistor solder joints aged at 100, 200 and 300 hours was influenced by the ageing reaction times. The results also indicate that an increase in ageing time and temperature does not have much influence on the formation and growth of Kirkendall voids. Research limitations/implications – A proper correlation between shear strength and fracture mode is required. Practical implications – The IMC thickness can be used to predict the shear strength of the component/printed circuit board pad solder joint. Originality/value – The shear strength of the 1206 chip resistor solder joint is a function of ageing time and temperature (°C). Therefore, it is vital to consider the shear strength of the surface-mount chip component in high-temperature electronics.

Sign in / Sign up

Export Citation Format

Share Document