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A comprehensive experimental and numerical study on flexural buckling behaviour of welded stainless steel box-section beam-columns is presented in this paper. A total of ten test specimens were prepared and tested subjected to eccentric compression. The cross-section and length of the test specimens were carefully designed by referring to existing design specifications to be insusceptible to local buckling. The full experimental load versus deformation and load versus strain curves were obtained. Prior to member testing, both material tests and geometric imperfection measurements were conducted and reported in detail. Finite element (FE) models were developed and validated against the obtained beam-column test results afterwards, which were utilised to perform parametric studies on the flexural buckling behaviour, generating sufficient numerical data points. Based on the obtained test and FE results, the design methods provided in EN 1993-1-4+A1 and AISC DG 27 were assessed. It was shown that both EN 1993-1-4+A1 and AISC DG 27 provided generally conservative and scattered predictions for the buckling resistance of welded stainless steel box-section beam-columns. Moreover, a newly revised proposed interaction factor was proposed in the framework of EN 1993-1-4+A1, and strength predictions with reduced scatter were therefore achieved.

The objective of this work is to develop design guidance for existing hollow steel columns that are retrofitted by infilling concrete into the tubes. The primary challenge is the unknown effect of the existing preload on the steel columns prior to the concrete infill. Composite performance and buckling behaviour of circular hollow section (CHS) steel columns strengthened by infilling concrete under preload was experimentally and numerically investigated in this study. A total of 34 CHS steel columns were tested under pin-ended boundary conditions, and the overall buckling failure modes and corresponding ultimate buckling resistances were recorded. Prior to the member testing, material properties of the steel columns and the infilled concrete were attained. By means of the finite element (FE) software package ABAQUS, elaborate FE models for the CHS columns strengthened by infilling concrete were developed and validated against the obtained test results, which were further verified with other available test data. Using the validated FE models, systematic parametric studies were conducted to examine the influences of the major factors affecting the ultimate capacities of the CHS columns strengthened by infilling concrete, including preload ratios, steel and concrete strengths, steel ratios, initial global imperfections, eccentricity ratios and column slenderness ratios. The obtained test and numerical results were therefore utilised to develop design criteria for predicting the overall buckling resistance of CHS steel columns strengthened by infilling concrete. In view of the difficulty of determining the key parameters in practice and the uncertainty of the strengthening process, a new simplified design coefficient was proposed, taking into account the influence of the preload. It has been demonstrated that accurate and reasonable strength predictions can be provided by the proposed design method.

This paper complements previous research conducted by the authors on stainless steel bolted joints and reports the first systematic study on the structural behaviour of stainless steel beam-to-tubular column joints with the use of Hollo-bolts. Six full scale specimens including two flush plate joints, two top and seat cleat connections, and two top, seat and web cleat connections of single-sided beam-to- hollow section column joints have been tested and the results are reported in detail. All specimens were in Grade EN 1.4301 austenitic stainless steel and were designed in such a way that a variety of failure modes could be obtained including plastification of the tubular column face, of the connecting angle cleats or the flush plates. For each specimen the moment-rotation response, the evolution of strains in critical locations of the connections and the separation between the column face and the connected beam was monitored and is reported herein. In parallel with the tests, advanced nonlinear FE models were developed. Following validation against the obtained experimental results, parametric studies were conducted to study the effect of key parameters such as, material grade, column face thickness, end plate/angle cleat thickness and bolt spacing on the stiffness, strength and ductility of the joints. Based on both the experimental and numerical results, it was verified that the connections displayed excellent ductility and attained loads much higher than the ones predicted by design standards for carbon steel joints.

The shear behaviour of stainless steel plate girders investigated in this study is related to the introduction of diagonal stiffeners. Four plate girders with or without diagonal stiffeners were fabricated by welding hot-rolled stainless steel plates of different thicknesses. All the plate girders were tested to failure subject to shear loading. The critical shear buckling stress, ultimate resistance and post-peak response were recorded and carefully analysed. Elaborate finite element (FE) models were developed by means of the FE software package ABAQUS and were validated against the test results. A comprehensive parametric analysis of key parameters including the web aspect ratio and slenderness, the flexural stiffness of diagonal stiffeners and the material properties was further conducted, reflecting the influence of these parameters on structural responses. The critical shear buckling stresses obtained from eigenvalue buckling analysis were compared with theoretical predictions of the elastic buckling stress, and a new calculation approach for the shear buckling coefficient of diagonally stiffened web panel that can account for the flexural stiffness of diagonal stiffeners and the effective restraint from flanges was proposed. Based on the obtained ultimate shear resistances, the existing design methods were assessed; and a new design proposal within the framework of EN 1993-1-4 + A1 for predicting the shear resistance of diagonally stiffened stainless steel plate girders was developed. In this novel method, the shear contributions from diagonal stiffeners and the shear buckling coefficients for diagonally stiffened web panels were revised. The reliability of the new proposal was also confirmed by further statistical analysis.

A comprehensive experimental study on structural behaviour of stainless steel bolted T-stub connections is presented in this paper. A total of 27 stainless steel bolted T-stubs with various geometric configurations were fabricated from hot-rolled stainless steel plates and assembled with stainless steel bolts. Two stainless steel grades − austenitic EN 1.4301 and duplex EN 1.4462, and two other types of stainless steel bolts − A4-70 and A4-80, were introduced in the experimental programme. Tensile coupon tests were performed to determine the material properties of the stainless steel plates and bolts. The bolted T-stub specimens were tested under monotonic loading, and ultimate resistances, plastic deformation capacities and failure modes were obtained. Based on the experimental results, the existing design methods for predicting tension resistances of the bolted T-stub connections, including design provisions in EN 1993-1-8, the continuous strength method (CSM), AISC manual and JGJ 82 and other design formulae for T-stubs with four bolts per row, were all evaluated. It was indicated that all the existing design methods provided generally conservative predictions for stainless steel bolted T-stub connections.

Research on stainless steel structures has primarily focused on the structural response of individual members, whilst the response of joints has received far less attention to date. This paper reports for the first time full-scale tests on stainless steel beam-to-column joints, subjected to static monotonic loads, whilst the companion paper reports numerical studies on similar connection typologies to the ones studied herein. The joint configurations tested include one flush and one extended end plate connection, two top and seated cleat connections, and two top, seated and web cleat connections of single-sided beam-to-column joints. All connected members and connecting parts including bolts, angle cleats and end plates are in Grade EN 1.4301 stainless steel. The full moment-rotation characteristics were recorded for each test and the experimentally derived stiffness and moment resistance for each joint was compared to the codified provisions of EN1993-1-8. It was verified that the connections displayed excellent ductility and attained loads much higher than the ones predicted by design standards for carbon steel joints.

A comprehensive experimental study on the structural behaviour of stainless steel T-stubs in Grade EN 1.4003 ferritic stainless steel and employing A4–80 stainless steel bolts is reported in this paper. A total of 17 ferritic stainless steel T-stubs of various geometric configurations including both single and double bolt rows were tested under monotonic tension. The focus of the tests was on T-stubs failing predominantly in mode 1. Auxiliary tensile tests were performed on coupons extracted from the T-stub flanges in three directions thereby enabling the material anisotropy to be quantified. The ultimate resistance, plastic deformation capacity and failure mode of each T-stub were obtained and are reported herein. The obtained results are utilised to assess the accuracy of existing design rules, which, contrary to austenitic and duplex stainless steels, seem to offer a good prediction of the experimentally determined plastic resistance. Finally, the applicability of recently proposed predictive equations accounting for membrane actions in carbon steel T-stubs to ferritic stainless steel T-stubs has also been assessed.

The behaviour of stainless steel plate girders subjected to combined bending and shear was experimentally studied in this paper. Both tensile and compressive material properties of the two adopted stainless steel alloys, including austenitic grade EN 1.4301 and duplex grade EN 1.4462, were determined by standard coupon tests. The three-dimensional (3D) optical scanning technology was introduced to acquire an accurate distribution of initial geometric imperfections for each plate girder specimen. A total of six plate girders were fabricated by hot-rolled stainless steel plates, and were tested to failure under combined bending and shear. In-depth analyses of the critical buckling characteristics, the ultimate resistances and the collapse behaviour of the tested specimens were all presented. The obtained ultimate resistances were further employed to assess the existing moment and shear (M-V) interaction design methods in EN 1993-1-5, GB 50017-2017, ANSI/AISC 360-16 and SEI/ASCE 8-02, and the design proposal presented by Jáger et al. It has been found that most of the existing codified M-V interaction formulae can be applicable for both carbon steel and stainless steel plate girders, yet they lead to relatively conservative predictions for stainless steel plate girders, except that the design method in ANSI/AISC 360-16 provides apparently unsafe strength predictions.

Welded tubular joints are widely used for the mast arm pole connection in signal support structures. In order to study the fatigue behavior of such welded tubular joints, static loading and fatigue tests were carried out on several full-scale experiments. In order to understand the local behavior and perform parametric study of critical factors such as initial crack location, finite element (FE) models are subsequently built and the numerical simulation results are validated with the experimental test results. Stress intensity factors (SIFs) at the deepest point of fatigue cracks are calculated by the FE method and an empirical equation are examined by comparison. It is found that the numerical simulation results are in good agreement with the experimental test results. The effect of initial crack location on the SIF and the fatigue life are also investigated. The Bowness equation will result in higher SIF value and more conservative fatigue life prediction for the concerned welded tubular joints. The SIFs at the deepest point decrease and fatigue life increases with the increasing initial crack angle.

The shear buckling behaviour of welded stainless steel plate girders with transverse stiffeners has been experimentally and numerically investigated in this paper. A total of seven plate girders with rigid/non-rigid end posts were fabricated from hot-rolled stainless steel plates, and each of the plate girders was subjected to a concentrated load at mid-span. The shear buckling characteristics and postbuckling behaviour were observed. Prior to testing, the initial local geometric imperfections and the material properties were accurately measured. The critical shear buckling strengths of the web plates were determined from the recorded surface strains and out-of-plane deflections, which were further compared with theoretically predicted values from elastic and inelastic assumptions. By using the general finite element (FE) software package ABAQUS, elaborated FE models were developed and validated against the obtained test results and other available existing test data. Upon validation of the FE models, parametric studies were subsequently carried out to explore the influences of initial local geometric imperfections, web aspect ratios, end post conditions, and material properties over a wide range of web slendernesses. The obtained test/FE results, together with other existing test data, were summarised to evaluate the current codified provisions in GB 50017, EN 1993-1-5, EN 1993-1-4, EN 1993-1-4+A1 and the design proposals from Estrada et al. Based on the test and numerical results, an alternative design approach that could account for the material non-linearity and rigid and non-rigid end posts has been proposed, which provides accurate and reasonable strength predictions for stainless steel plate girder with transverse stiffeners.

This paper focuses on the hysteretic performance of stainless steel beam-to-column joints with double extended end-plate connections under cyclic loading. Six full-scale joint specimens were fabricated, including three interior column joints and three exterior column joints. Two stainless steel grades — austenitic grade EN 1.4301 and duplex grade EN 1.4462, and one carbon steel grade Q345B were considered. A4-80 stainless steel bolts and grade 10.9 high strength steel bolts were employed to assemble the joint specimens. The cyclic loading tests were conducted using the loading protocol set in Chinese standard JGJ/T 101. The force versus displacement (F- Δ ) hysteresis curves were recorded, and the failure modes, the ductility, the strength and stiffness degradation, and the energy dissipation capacity of the tested joints were analysed and discussed in detail. Empirical hysteresis models were developed and calibrated against the recorded hysteretic curves and energy dissipation capacities of the tested joints. The experimental results involving the initial rotational stiffness values and the moment resistances were further utilised to evaluate the accuracy of current design provisions codified in EN 1993-1-8, ANSI/AISC 358 and GB 51022. The comparison shows that the development of accurate design guidance accounting for the pronounced strain hardening of stainless steels is warranted.

The compressive buckling behaviour of extruded aluminium alloy I-section columns with fixed-pinned end conditions has been experimentally and numerically investigated in this study. A total of 11 column tests, involving two heat-treated aluminium alloys – 6061-T6 and 6063-T5, were carried out to acquire the compressive buckling strengths. Prior to the column tests, material properties of the two aluminium alloys were determined from tensile coupon tests, while the initial local and global geometric imperfections were separately measured by means of experimental techniques. By using the ABAQUS software package, finite element (FE) models that could account for material non-linearity and initial geometric imperfections were developed. The FE models were further validated against the test results, enabling reliable simulation of the compressive buckling behaviour of the tested columns with fixed-pinned end conditions. Based on the obtained test and numerical results, the calculation methods in the current design standards, including the European, Chinese, American and Australian/New Zealand specifications, were all assessed. It was shown that the design provisions in all the four standards provided relatively conservative strength predictions, especially for the aluminium alloys with more pronounced strain hardening capacity.

Flexural buckling behavior of stainless steel columns has been widely investigated and discussed. However, a barely explored area is that of welded-section members. In this paper, twelve full-scale columns buckling tests have been conducted for both austenitic and duplex welded stainless steel box-section members. Specimen cross-sections and lengths have been selected to cover a wide range of geometries, varying between non-dimensional slenderness of 0.5 and 2.0. Measurements of material properties, residual stress and initial geometric imperfection have been also conducted. Relevant numerical simulation has been performed, accuracy of which is verified by comparing with the test results. The test results have been used to assess the applicability of the EN 1993-1-4, ASCE 8-02 and AS/NZS for stainless steel welded-sections. It shows that current design method predicts the buckling resistance of welded stainless steel box-section generally conservative thus improvement could be anticipated.

Building upon a previous investigation, this study reports a total of 13 experimental tests on austenitic and duplex stainless steel T-stubs subject to monotonic loading. The structural behaviour of the tested T-stub specimens, including load versus displacement (F-Δ) curves and corresponding failure modes, was obtained and is reported herein. The experimental tests were replicated by finite element (FE) analysis, and upon validation of numerical models, a comprehensive parametric study including 168 FE models was conducted to investigate the effects of key parameters such as material grade, bolt preloading, bolt diameter and flange thickness on the structural response. Based on both experimental and numerical results, the suitability of the design provisions for the determination of the plastic resistance specified in EN 1993-1-8, proposed extensions thereof by Demonceau et al. to cover T-stubs with four bolts per row for stainless steel T-stubs as well as the design method codified in Chinese code JGJ 82 were assessed. Novel design methods for the determination of the initial stiffness and the plastic resistance of stainless steel T-stubs, accounting explicitly for the observed structural response and the pronounced material strain hardening were developed. The proposed design methods lead to improved and more consistent capacity predictions and their adoption in design standards is recommended herein.

The structural behaviour of beam-to-column joints with double extended end-plate connections is experimentally and numerically investigated in this paper. Two stainless steel grades representing austenitic and duplex stainless steel (i.e. EN 1.4301 and EN 1.4462 respectively) have been considered, whilst a joint made of the carbon steel grade Q345B was also tested as a benchmark to enable direct comparison of carbon and stainless steel joints. The employed bolt grades were A4-80 stainless steel bolts and 10.9 high strength bolts. A total of six full-scale joint specimens were tested including five stainless steel joints and one carbon steel control specimen and the applied force versus displacement (F-Δ) curves, as well as the corresponding moment versus rotation (M-ϕ) curves, were recorded and are reported herein, demonstrating excellent ductility behaviour of stainless steel joints. Advanced finite element (FE) models were developed using the ABAQUS software package and validated against the obtained test results, in terms of the obtained F-Δ curves and failure modes. The obtained initial rotational stiffness, plastic moment resistance and rotation capacity of the tested joints, were used to assess the accuracy of the predictions of the relevant European. American and Chinese design codes – EN 1993-1-8, ANSI/AISC 358-16 and GB 51022-2015 respectively – all of which are based on the respective design equations developed for carbon steel joints. It is concluded that the existing design standards lead to overly conservative strength predictions for stainless steel joints, as they fail to account for the significant strain-hardening and ductility of the material. Hence the development of novel design guidance in line with the observed response is warranted.

A comprehensive experimental programme has been carried out to investigate the local buckling and postbuckling strengths of aluminium alloy I-section stub columns. A total of 15 test specimens made of two heat-treated aluminium alloys (6061-T6 and 6063-T5) were fabricated by extrusion. The material properties were acquired by the tensile coupons cut directly from the extruded cross-sections. The local geometric imperfections in sections were accurately measured prior to the tests. The stub column specimens were tested under axial compression between two fixed end supports, during which the local plate buckling featured visibly for each test specimen before reaching the peak load. The critical local buckling strengths were determined from the measured out-of-plane deflections and surface strains corresponding to the plate elements, which were further compared with the theoretical and analytical values taking into account element interaction and material non-linearity. Based on the obtained experimental postbuckling strengths, the design provisions in current design standards, including the American, Australian/New Zealand, European and Chinese specifications, were all evaluated. It was revealed that the predicted compressive strengths from the four design standards were generally conservative, especially for the cross-sections made of aluminium alloys with pronounced strain hardening properties.

This paper presents twenty-eight stub columns tests on stainless steel built-up sections. The test specimens, including I-sections, square hollow sections (SHS) and rectangular hollow sections (RHS), were fabricated by shielded metal arc welding (SMAW) from hot-rolled plates of nominal thicknesses 6 mm and 10 mm. The twenty-eight stub columns, of two stainless steel alloys (austenitic EN 1.4301 and duplex EN 1.4462), were tested in pure axial compression. Both tensile and compressive material properties were obtained by means of coupon tests in three directions – longitudinal, diagonal and transverse to the rolling direction. Geometric imperfection measurements for each specimen were conducted by means of a calibrated electric guideway, and residual stress distributions in the built-up sections were determined by means of the sectioning method. The test strengths were used to evaluate the design strengths predicted by EN 1993-1-4, the Continuous Strength Method (CSM) and the direct strength method (DSM). It was demonstrated that the predicted strengths from EN 1993-1-4 provisions were generally conservative, while both the CSM and the DSM predicted values were closer to the test strengths.

The present investigation studies the overall stability bearing capacities of stainless steel welded I-section beams. Experimental tests of 8 specimens have been conducted. In addition, complementary finite element (FE) models, which have been validated by the test results, are adopted to calculate the overall stability bearing capacities of the beams. Based on the results of FE analyses and experimental tests, as well as the comparisons of design standards for buckling reduction factor calculations of stainless steel structural components, two calculation methods for buckling reduction factors of welded I-section beams are proposed. One is the modification of Chinese code for design of steel structures, and the other is regressed by the FE analysis results. Both methods are conservative and have simple formulations for engineering design.

Investigations on lateral-torsional buckling behavior of stainless steel welded I-section beams were carried out through fourpoint bending tests. The Chinese austenitic stainless steel adopted in this study contains approximately 17% of Cr, which could be graded as EN 1.4401. The non-linear stress-strain relationship of the material, the residual stress distribution of the section and the ultimate moment capacity of the welded I-section beams were obtained from the experiments, and they were compared with those results predicted by analytical models recommended by several researchers. Besides, a new model is proposed to predict the residual stress distribution of the stainless steel welded I-section beams.

Preload in a cast-in-situ concrete-filled steel tube (CFST) structure is an important parameter that has been studied and considered in design and construction. However, the impact of a preload on fire resistance of CFST has not been taken into account in the existing design method of CFST under fire. In this paper, twelve CFST columns with and without preload in the steel tubes are experimentally studied to investigate their heating process, failure modes, thermal and structural responses. The test results show that preload of the steel tube has significant impact on the fire resistance of some of the columns. Further investigations on this important observation will be done numerically in a companion paper [24] to carry out a more comprehensive parametric study.

Experimental and numerical investigations on bearing capacity of non-linear metallic spiders used in glass facades were presented. The non-linear metallic materials adopted in this study included two aluminum alloys (ZL105-T1 and ZL111-T6) and one austenitic stainless steel (AISI 302). A total of 21 spider specimens including three types of configurations were tested. Numerical simulation of the tests was conducted by virtue of sophisticated finite element (FE) models built up with ANSYS software. The test and FE predicted results were used to develop new design proposals for the spiders. Evaluation of the proposed design formulae revealed that a comparatively large safety margin would be appropriate in consideration of brittle glass panels. Finally, safety assessment of the spiders was conducted based upon a practical engineering application-the exhibition greenhouse in Beijing Botanical Garden.

This paper presents a detailed investigation into lateral-torsional stability of aluminium extruded I section beams under pure bending. Forty aluminium members of two different alloys 6061-T6 and 6063-T5, representing weak hardening and strong hardening alloys respectively, were tested. Stress–strain relationships were determined by tensile tests with 8 coupons cut from extruded flanges and web. Widths of flanges and lengths of members were herein taken as primary parameters to study lateral-torsional stability of the beams. With rigid lateral-torsional restraint on beam ends, lateral-torsional buckling resistances and load-rotation relationships were obtained by continuous loading. Comparison of numerical predictions with test results indicated that accurate and reliable replication could be achieved by the described finite element (FE) models. By means of measured material behaviour and geometric properties, the corresponding provisions in Eurocode 9 (CEN 2007) and a design method previously proposed by the authors were evaluated by the test results. It was demonstrated that the proposed calculation method could provide cross-section lateral-torsional buckling resistances that are much closer to the test results than design strengths on the basis of the Eurocode 9 provisions are. Therefore, the proposed design method could be an alternative way of predicting the lateral-torsional buckling resistances of aluminium alloy I-beams.

The principle of a flat nano-metallic surface plasmonic lens is analyzed based on phase matching and effective refractive index theory. The complex relationships between the macro-parameters such as focal length with other design freedoms, e.g. material properties of the lens, sheet thickness, slit width, and slit pitch, are disclosed as well. A set of tailored formulae are derived for the design of such a nano-metallic surface plasmonic lens. Several simplified implementations of the nano-metallic lens such as a lens with equidistant slits but bearing different widths, and a lens with equal slit widths but different pitches are given. The performance of the beyond-diffraction-limit focusing effect is given as well.

The local–overall interactive buckling behaviour of welded stainless steel I-section columns was experimentally and numerically examined in this study. A total of ten test specimens were fabricated from hot-rolled stainless steel plates and axially loaded between two pin-ended supports. The specimens failed by local–overall interactive buckling about the minor axis. Prior to the member testing, material properties, residual stresses and initial local and global geometric imperfections were all accurately determined. Detailed finite element (FE) models, capable of simulating the interactive buckling behaviour and predicting the ultimate capacity of welded stainless steel I-section columns, were validated against the obtained test results. The validated FE models were subsequently used to carry out systematic parametric studies, exploring the influences of the key input parameters, including the welding residual stresses, initial geometric imperfections, material properties and slenderness ratios. The generated test and numerical results were then used to assess the accuracy of a series of existing design methods: Eurocode 3 Part 1.4 and the design proposal of Rasmussen and Rondal, both of which employ the effective width concept, and the two separate design proposals of Becque et al. in the EN 1993-1-4 and AS/NZS 4673 formats and the proposal of Huang and Young, all of which are based on the direct strength method (DSM). Based upon the assembled data points, two separate design curves are proposed herein for austenitic and duplex stainless steels, which have been demonstrated to offer very accurate strength predictions for welded stainless steel I-section columns undergoing interactive buckling.

Residual stress magnitudes and distributions in structural stainless steel built-up sections have been comprehensively investigated in this study. A total of 18 test specimens were fabricated from hot-rolled stainless steel plates by means of shielded metal arc welding (SMAW). Two grades of stainless steel were considered, namely the austenitic grade EN 1.4301 and the duplex grade EN 1.4462. Using the sectioning method, the test specimens were divided into strips. The residual stresses were then computed by multiplying the strains relieved during sectioning by the measured Young׳s moduli determined from tensile and compressive coupon tests. Residual stress distributions were obtained for 10 I-sections, four square hollow sections (SHS) and four rectangular hollow sections (RHS). Peak tensile residual stresses reached around 80% and 60% of the material 0.2% proof stress for grades EN 1.4301 and EN 1.4462, respectively. Based upon the test data, simplified predictive models for residual stress distributions in stainless steel built-up I-sections and box sections were developed. Following comparisons with other available residual stress test data, the applicability of the proposed models was also extended to other stainless steel alloys. The proposed residual stress patterns are suitable for inclusion in future analytical models and numerical simulations of stainless steel built-up sections.

Surface passivation of single crystal bulk grown Ga 1− x In x Sb with x =0.08–0.18 is investigated using anodically grown native oxide and MOS devices. Electrical characterization of the interface is performed by using capacitance–voltage and conductance–voltage measurements at room temperature. The as-grown film shows relatively large hysteresis and high densities of negative (positive) fixed interface charges at the n- (p-) type interface. A long-time low-temperature annealing significantly improves interface properties, while a high temperature annealing degrades the interface. Very good interface properties are obtained for n-type wafers, with a fixed interface charge density of around mid 10 10 cm −2 (either positive or negative), an interface trap density in the range of low 10 11 to less than 1×10 10 cm −2 eV −1 and a small hysteresis induced by slow trap effect. In contrast, the p-type interface is always characterized by a high density of interface traps which leads to low-frequency-type C – V curves even at 1 MHz.

The operation mechanism of the Si homojunction interfacial workfunction internal photoemission far-infrared detector is based on internal photoemission occurring at the interfacial barrier between a heavily doped absorber/emitter layer and an intrinsic (i) layer. Due to the free carrier “spill over” from the emitter to the i layer, a space charge region is created near the interface, which was neglected in the previous detector performance analyses. In this paper, we calculate the distributions of free electron concentration, ionized donor concentration, potential barrier, and electric field in the space charge region, for an n+-i structure with a thick i layer at low temperatures, by numerically solving the drift-diffusion equation. The dependence of these distributions on applied bias, temperature, and i layer doping level, are investigated. By using these results, the previous experimental results obtained from commercial Si p-i-n diodes can be well explained. PACS numbers: 85.60.Gz, 79.60.Jv, 73.40.Lq, 77.50.

Through the systematic study of spatial structure of aluminum alloy and the summary of traditional joints type used in aluminum alloy spatial structure, a new type of joint: cast aluminum joint is put forward. The design procedure and calculation method of the cast aluminum joint is discussed and design suggestion is given. Combined with practical work, the mechanical properties of the cast aluminum joint are analyzed. This paper is not only help for the spread and use of the cast aluminum joint, but also apply reference for projects design.

Conventional magnetic recording has been projected to suffer from superparamagnetic instabilities at high bit densities. Heat assisted magnetic recording (HAMR) is one of the promising approaches to overcome this problem. The track where writing is taking place is heated and cooled rapidly. The lubricant is therefore required to withstand repeated temperature changes from room temperature to above 300degC in a few nanoseconds. In order to improve thermal stability, series novel lubricants with appropriate molecular weight and functional end groups were synthesized in this study. The friction coefficient for Lube-1 film is lower than that of Z-dol film in all test rotating speed range. The Lube-1 film has good initial uniformity and excellent thermal stability and antilaser irradiation property. In addition, Lube-1 performs better tribology property compare to commercial available lubricants.

alpha-Synuclein and ubiquitin are two Lewy body protein components that may play antagonistic roles in the pathogenesis of Lewy bodies. We examined the relationship between alpha-synuclein, ubiquitin, and lipids in Lewy bodies of fixed brain sections or isolated from cortical tissues of dementia with Lewy bodies. Lewy bodies exhibited a range of labeling patterns for alpha-synuclein and ubiquitin, from a homogeneous pattern in which alpha-synuclein and ubiquitin were evenly distributed and overlapped across the inclusion body to a concentric pattern in which alpha-synuclein and ubiquitin were partially segregated, with alpha-synuclein labeling concentrated in the peripheral domain and ubiquitin in the central domain of the Lewy body. Lipids represented a significant component in both homogeneous and concentric Lewy bodies. These results suggest that Lewy bodies are heterogeneous in their subregional composition. The segregation of alpha-synuclein to Lewy body peripheral domain is consistent with the hypothesis that alpha-synuclein is continually deposited onto Lewy bodies.

This paper aims to develop design methods for the shear strength of welded stainless steel I-shaped members. The current American AISC Design Guide 27 has been published for Structural Stainless Steel, and it refers to the specification ANSI/AISC 360-16 for structural steel buildings for the shear strength without considering tension field action (TFA). All the available test data on stainless steel plate girders were collected from literatures and employed to assess the provisions in the Design Guide 27, as well as the codified ones in Eurocode 3 Part 1.4. Based on the test results and obtained comparisons, two new proposals for unstiffened webs or webs with transverse stiffeners widely spaced (without TFA), and for interior webs with stiffeners spaced at 3hw or smaller (considering TFA) were developed and presented to match the format of the expressions in ANSI/AISC 360-16 for stainless steel webs under shear. Reliability analysis was further performed to calculate the Load and Resistance Factor Design (LRFD) resistance factors determined by the new proposals and to further justify the target factor in AISC Design Guide 27 for structural stainless steel.