Time filter

Source Type

Vancouver, WA, United States

Lin W.,Circle Technology
Proceedings - Electronic Components and Technology Conference | Year: 2015

One of the current trends for advanced packages is increasingly thinner packaging for mobile devices. Thin packages increase warpage tremendously making control of package warpage very critical and challenging. Furthermore, a thin package is also much more sensitive to various factors including incoming conditions, processing conditions and nonlinear material behaviors. As a result, current warpage models based purely on the finite element method (FEM) have difficulty accurately predicting the warpage of packages in an actual production environment because the models are not able to capture all the complicated process issues as well as material nonlinearities. On the other hand, current advanced packages are mostly custom built with fast development cycles. Avoiding problems requires a feasible method to predict warpage during the package development stage to guide the design improvement. This paper presents a new feasible method to accurately predict package actual warpage in production based on a finite element model integrated with empirical shadow moiré warpage data. The unique aspect of this method uses existing empirical warpage data from a broad range of different package types and design parameters to estimate the actual reference temperature point as well as an initial warpage as inputs into the FEM warpage simulation model. The adjusted actual reference temperature and the initial warpage are used to account for any warpage caused by unknown factors in the assembly processes and materials which cannot be captured by the FEM model. Through the product development cycle, the semi-empirical warpage model is continually updated as more and more new empirical data are available making it more and more accurate for next-cycle predictions. This paper uses a Package-On-Package (POP) and a flip-chip Chip-Scale-Package (fcCSP) as test vehicles to illustrate this unique semi-empirical warpage prediction method. © 2015 IEEE.

Rudy C.W.,Circle Technology
Laser Focus World | Year: 2014

Mid-infrared lasers with wavelengths from 2 to 20 μm continue to advance as both new and higher-quality doped optical fibers, solid-state materials, and nonlinear optical devices are developed for this wavelength range. The structure of mid-IR sources based on interband transitions closely resemble double hetero-junction semiconductor lasers in more established wavelength ranges, where the active region has a lower bandgap and larger index of refraction than the surrounding material for carrier and photon confinement. The midIR lasers are both compact and electrically driven. Q-switched, gain switched, and mode-locked pulses have been generated by mid-IR fiber lasers. Several solid-state mid-IR lasers with trivalent rare-earth ions have been developed, with the most common dopants being Tm3+, Ho3+, and Er3+, with emission wavelengths similar to the rare-earth-doped fiber lasers.

Deditius A.P.,Murdoch University | Reich M.,University of Chile | Kesler S.E.,University of Michigan | Utsunomiya S.,Kyushu University | And 3 more authors.
Geochimica et Cosmochimica Acta | Year: 2014

The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ~30 to ~600°C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ~200 to ~500°C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and alteration by hydrothermal fluids. The second trend consists of pyrites from porphyry Cu and epithermal Au deposits, which are characterised by compositions that preserve the Au/As signature of mineralizing magmatic-hydrothermal fluids, confirming the role of this sulfide in controlling metal ratios in ore systems. © 2014 Elsevier Ltd.

Wickens C.D.,Circle Technology
Human Factors | Year: 2014

Objective: The aim of this study was to demonstrate the importance of effort in human factors.Background: Effort has made its appearance in several diverse formats and applications. Eight of these are integrated in the current writing related to learning, looking, task switching, visual search termination, information access, choosing decision strategies, and behaving safely.Method: This is based upon a literature review.Results: The common elements of these different effort applications are highlighted, particularly, their manifestations in either implicit or explicit expected value decisions.Conclusions: There is a need to show how the metrics of effort and workload assessment influence decisions in human factors, particularly, those related to safety. Copyright © 2014, Human Factors and Ergonomics Society.

Pierson K.J.,North Carolina State University | Eggleston D.B.,North Carolina State University | Eggleston D.B.,Circle Technology
Transactions of the American Fisheries Society | Year: 2014

Restoration of oyster reefs is increasing worldwide due to oyster populations reaching historic lows and recognition of the many ecosystem services provided by oyster reefs, such as essential fish habitat. This study took advantage of an existing network of subtidal oyster reefs and a large-scale oyster reef restoration effort in Pamlico Sound, North Carolina, to (1) compare estuarine fish assemblages on oyster reefs with those on unstructured bottom, (2) identify the short-term change in fish abundance and richness in response to reef creation, and (3) identify spatiotemporal trends in fish abundance and richness. We quantified transient and reef fish using gill nets and fish traps, respectively. Oyster reefs harbored more unique species than unstructured bottom, thereby enhancing the overall diversity of estuarine fish assemblages. Fish abundance on recently created experimental reefs (6-8 months postconstruction) was similar to that on control reefs that were 4-6 years old, suggesting rapid colonization of new reefs. Fish diversity at 1 of 2 sites actually decreased on control reefs after reef construction, suggesting that rapid colonization of new reefs was due, in part, to the movement of fish from old to new reefs. Information on the distribution, abundance, and diversity of estuarine fish in relation to restored oyster reefs will improve our understanding of oyster reefs as essential fish habitat. Received June 12, 2013; accepted September 14, 2013. © 2014 Copyright Taylor and Francis Group, LLC.

Discover hidden collaborations