SUMMARY A series of hybrid and cyclic loading tests were conducted on a three‐story single‐bay full‐scale buckling‐restrained braced frame (BRBF) at the Taiwan National Center for Research on Earthquake Engineering in 2010. Six buckling‐restrained braces (BRBs) including two thin BRBs and four end‐slotted BRBs, all using welded end connection details, were installed in the frame specimen. The BRBF was designed to sustain a design basis earthquake in Los Angeles. In the first hybrid test, the maximum inter‐story drift reached nearly 0.030 rad in the second story and one of the thin BRBs in the first story locally bulged and fractured subsequently before the test ended. After replacing the BRBs in the first story with a new pair, a second hybrid test with the same but reversed direction ground motion was applied. The maximum inter‐story drifts reached more than 0.030 rad and some cracks were found on the gusset welds in the second story. The frame responses were satisfactorily predicted by both OpenSees and PISA3D analytical models. The cyclic loading test with triangular lateral force distribution was conducted right after the second hybrid test. The maximum inter‐story drift reached 0.032, 0.031, and 0.008 rad for the first to the third story, respectively. This paper then presents the findings on the local bulging failure of the steel casing by using cyclic test results of two thin BRB specimens. It is found that the steel casing bulging resistance can be computed from an equivalent beam model constructed from the steel core plate width and restraining concrete thickness. This paper concludes with the recommendations on the seismic design of thin BRB steel casings against local bulging failure. Copyright © 2011 John Wiley & Sons, Ltd.

Microfluidic systems have attracted considerable attention and have experienced rapid growth in the past two decades due to advantages associated with miniaturization, integration, and automation. Poor detection sensitivities mainly attributed to the small dimensions of these lab-on-a-chip (LOC) devices; however, sometimes can greatly hinder their practical applications in detecting low-abundance analytes, particularly those in bio-samples. Although off-chip sample pretreatment strategies can be used to address this problem prior to analysis, they may introduce contaminants or lead to an undesirable loss of some original sample volume. Moreover, they are often time-consuming and labor-intensive. Toward the goals of automation, improvement in analytical efficiency, and reductions in sample loss and contamination, many on-chip sample preconcentration techniques based on different working principles for improving the detection sensitivity have been developed and implemented in microchips. The aim of this article is to review recent works in microchipbased sample preconcentration techniques and give detailed discussions about these techniques. We start with a brief introduction regarding the importance of preconcentration techniques in microfluidics and the classification of these techniques based on their concentration mechanisms, followed by in-depth discussions of about these techniques. Finally, personal perspectives on microfluidic-based sample preconcentration will be provided. These advancements in microfluidic sample preconcentration techniques may provide promising strategies for improving the detection sensitivities of LOC devices in many practical applications.

I mmunoassays have long been widely used in a variety of applications, such as for medical diagnostics, pharmaceutical analysis, environmental, food safety testing, and for basic scientific investigations because of its simplicity, sensitivity, and specificity. Microfluidic systems, also well known as a ''lab-on-a-chip'' or a ''micro-total-analysis-system'' have attracted a lot of attention in the past two decades because of advantages associated with miniaturization, integration, and automation. A promising platform for the combination of these two technologies, microfluidic immunoassays, has been extensively explored in recent years. The aim of this article is to review recent advancements in microfluidic immunoassays. A brief introduction to immunoassays and microfluidic devices will include a literature review, followed by an in-depth discussion of essential techniques in designing a microfluidic-based immunoassay from different perspectives, including device substrates, sample/reagent transportation, surface modification, immobilization, and detection schemes. Finally, future perspectives on microfluidic immunoassays will be provided. These developments with microfluidic immunoassays may provide a promising tool for automatic, sensitive, and selective measurements in practical applications.

Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research.

This paper is the second part of a two-part paper presenting the cyclic tests of four two-story narrow steel plate shear walls (SPSWs). The first paper introduces the analytical studies and the specimen designs. This paper describes the test results. Some design implications including the capacity design for the first story column and the width-to-thickness ratio check for the beam web are discussed based on key observations from the tests. Test results confirm that the simplified strip model can accurately predict the inelastic responses of the specimens. Test results also confirm that the proposed capacity design method is effective in ensuring the plastic hinge formation at the bottom end of the first story column for SPSW with or without restrainers. Test results also show that the horizontal restrainers are effective in reducing the member forces in the boundary beam and column elements. Comparing the test results of the typical SPSW with those of the restrained SPSW (R-SPSW) specimens, it is found that the R-SPSW possesses an improved cyclic performance and reduced material weight. Analytical results predict the compressed column moments at the onset of the column plastic hinge formation well. The analytical hysteretic energy distribution in the first story column agrees very well with the observed inelastic actions developed in the four specimens. The detailed frame response analyses and the test results confirm that the assumptions made in developing the proposed column capacity design method are reasonable.KEY WORDS: steel plate shear wall (SPSW); restrained steel plate shear wall (R-SPSW); capacity design; narrow steel plate shear wall Figure 1. Details of the specimens.beam-to-column joint for both the middle and the top beams. Thus, the unbraced length of the columns was equal to the story height. A reference column was erected to measure the lateral displacement of the specimens at various elevations ( Figure 2). Positive values of force or displacement indicated pushing or movement toward the east direction. The cyclic displacements were imposed according to the loading history shown in Figure 3, starting from small roof drift and increasing up to 5% radian. The north actuator was displacement controlled while the south one was force-slaved.

SUMMARYThis study consists of two parts. In this two-part research, four two-story narrow steel plate shear walls (SPSWs) were cyclically tested at the Taiwan National Center for Research on Earthquake Engineering in 2007. This paper, Part 1, proposes a capacity design method for the first-story boundary column of the SPSW to ensure that the plastic hinges form at the column bottom ends when the SPSW develops the plastic mechanism. The design method was developed based on the superposition method considering the frame sway action and the panel force effects of the SPSW. Restrained steel plate shear wall (R-SPSW) studied herein adopts pairs of the horizontal restrainers sandwiching over both sides of the infill panels and connected to the boundary columns. Analytical studies on four SPSW example designs using nonlinear finite element (FE) models and the simplified strip models confirm that the restrainers could also effectively reduce the column force demands and allow the infill panel to stretch more uniformly. In addition, the FE analytical studies verify the effectiveness of the proposed column capacity design method and the seismic design recommendations for the restrainer. This paper introduces the designs of the four narrow SPSW specimens, presenting the selections of the boundary beams and columns, the designs of the beam-to-column connections and the construction details of the restrainers. The experimental results, key observations and the design implications are reported in the companion paper.

Abstract-A highly miniaturized 2.45/5.7 GHz dual-band bandpass filter is presented in this paper. It shows that the proposed filter which combines different sizes of open-loop resonators can excite two desired passbands. With the meandered technology and fractal geometry, the overall size is extremely compact compared with the published dual-band bandpass filters. Furthermore, the skirt selectivity of the proposed filter with two transmission zeros locating at both sides of the passbands is much improved. The rejection of the spurious response from 6.7 GHz to 14.5 GHz is successfully suppressed to the level lower than −15 dB. The occupied area of the proposed filter is 9.8 × 8.7 mm 2 . The measurement is in good agreement with the simulation.

SUMMARY Coupled steel plate shear wall (C‐SPSW) consists of two or more steel plate shear walls interconnected by coupling beams at the floor levels. In this study, a six‐story C‐SPSW prototype building was designed. A 40% scale C‐SPSW specimen, which is representative of the bottom two‐and‐half‐story substructure of the prototype, was cyclically tested using Multi‐Axial Testing System at the National Center for Research on Earthquake Engineering in 2009. In addition to a constant vertical force representing the gravity load effects, cyclic increasing displacements and the corresponding overturning moments transmitted from the upper stories were computed online and simultaneously applied on the substructural specimen. This paper firstly introduces the designs of the prototype C‐SPSW and the test specimen. Then, the test results and the numerical simulation are discussed in detail. Test results confirm the effectiveness of the proposed column capacity design method, which aims at limiting the plastic hinge formation within the bottom quarter height of the bottom column. Test and analytical results suggest that the coupling beam rotational demands can be estimated as the design story drifts when the formation of desirable plastic mechanism of the C‐SPSW is expected. Copyright © 2011 John Wiley & Sons, Ltd.