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This study investigated the flow bifurcations of flows driven by a pressure gradient in a rectangular curved tube. When fluid flows within a curved tube, due to the centrifugal effect, secondary vortices can be induced in the cross section of the tube. The secondary flow states are dependent on the magnitude of the pressure gradient (q) and the aspect ratio (γ). In this study, the continuation method was applied to investigate the flow bifurcations in a curved tube with increasing pressure gradient (1 < q < 6000) and aspect ratio (0.9 < γ < 1.4).
The bifurcation diagrams are composed of solution branches, which are linked by limiting points or bifurcation points. The flow states in a solution branch belong to the same group. The ranges of the flow states and the relationship between the states can also be derived from the bifurcation diagrams. In this study, two types of bifurcation were found, one in the range of 0.9 < γ < 1.17, and another in the range of 1.18 < γ < 1.4. The ranges of stable flow solutions and the distributions of limit and bifurcation points in both pressure gradient and aspect ratio are derived in this study.
Prior to integrated circuit (IC) packaging, die performance must be verified using probe cards to screen for defective products. With the decrease in IC line width, the dimensions of the pads used for performance verification and the spacing between adjacent pads have also decreased. However, when the pad pitch is reduced to less than 30 μm, commonly used probe cards will face manufacturing problems in miniaturization. To resolve probe card manufacturing problems caused by the miniaturization of IC components, the use of an anisotropic conductive film (ACF) in probe cards was proposed in this study. Theoretical calculations and experimental testing of this probe structure were conducted to demonstrate the feasibility of this concept.
In theoretical calculations, composite material and buckling theory were utilized to evaluate the buckling behavior of the ACF. In experimental testing, photolithography and electroplating techniques were used to control the line width and spacing intervals of the micron-scale metal wires in the ACF. After the ACF was fabricated, the mechanical properties of the ACF during wafer testing were assessed. Theoretical analyses and experimental testing verified that ACFs can potentially be applied to the performance verification of IC products. In the ACF structure, multiple probes came into contact with each pad. Therefore, ACFs can potentially be applied to the performance verification of IC components with pad diameters of less than 20 μm. The results of this study directly benefit the miniaturization of ICs.
Through silicon via (TSV) is the critical structure for three dimensional (3D) integration, which provides vertical interconnection between stacking dies. In TSV structure, large coefficient differences of thermal expansion exist between silicon substrate, dielectric material, and filled metal. Due to the large thermal mismatch, the high thermal stress occurring at the interface of different materials would result in delamination. Therefore, thermal-mechanical reliability is a key issue for 3D integration. In this study, we investigated the thermal-mechanical stress distribution of TSV under the condition of the accelerated thermal cycling loading by finite element analysis based on a 3D model of TSV structure. Due to the thermal expansion, that the TSV structure squeezed the surface area between TSVs at a high temperature resulted in compressive stresses at the surface area between TSVs. Therefore, a proper distance between the stress-sensitive device and the TSV should be kept. The stress analysis shows that the maximum thermal stress occurs in the outside region of TSV interface and in the annular region of TSV at a high temperature and at a low temperature, respectively. This study helps to obtain a clear thermal stress distribution of TSV and possible failure regions can be determined.
Pregnancy-associated pyogenic granuloma (pregnancy tumour) is not uncommon. However, control of severe bleeding associated with the lesion by transarterial embolisation has never been reported.
We report the case of a 33-year-old pregnant woman (34 weeks gestation) who presented with a pregnancy-associated pyogenic granuloma of the mandibular gingiva with a life-threatening haemorrhage. The bleeding stopped soon after transarterial micro-embolisation and regressed after one month; thus, no further surgical excision was needed. The patient was free of post-operative wound pain and infection, and there was no recurrence after one year of follow up.
In general, surgical excision is the first treatment choice for pregnancy tumours. However, it is limited by the risk of marked deformity or incomplete excision when large lesions or difficult surgical areas are encountered. For large tumours, transarterial embolisation may be a safer alternative.
Haemangioma of the adult larynx is an uncommon, benign lesion. The optimal surgical method of treating these lesions is controversial because only very limited case series are available. This paper reports the results of transoral robotic resection of a supraglottic haemangioma in an adult and reviews the literature.
Methods and results:
A 58-year-old woman presented having experienced a lump-in-the-throat sensation for 1 year. Investigations on laryngoscopy revealed a lobulated, dark red mass in the region of the supraglottis. This was successfully excised by transoral robotic excision without complications.
Adult supraglottic haemangiomas can be treated successfully with transoral robotic excision; this potentially allows more of the surrounding mucosal tissue to be spared and enables easy control of bleeding.
An uneven neurocognitive profile is a hallmark of autism spectrum disorder (ASD). Studies focusing on the visual memory performance in ASD have shown controversial results. We investigated visual memory and sustained attention in youths with ASD and typically developing (TD) youths.
We recruited 143 pairs of youths with ASD (males 93.7%; mean age 13.1, s.d. 3.5 years) and age- and sex-matched TD youths. The ASD group consisted of 67 youths with autistic disorder (autism) and 76 with Asperger's disorder (AS) based on the DSM-IV criteria. They were assessed using the Cambridge Neuropsychological Test Automated Battery involving the visual memory [spatial recognition memory (SRM), delayed matching to sample (DMS), paired associates learning (PAL)] and sustained attention (rapid visual information processing; RVP).
Youths with ASD performed significantly worse than TD youths on most of the tasks; the significance disappeared in the superior intelligence quotient (IQ) subgroup. The response latency on the tasks did not differ between the ASD and TD groups. Age had significant main effects on SRM, DMS, RVP and part of PAL tasks and had an interaction with diagnosis in DMS and RVP performance. There was no significant difference between autism and AS on visual tasks.
Our findings implied that youths with ASD had a wide range of visual memory and sustained attention impairment that was moderated by age and IQ, which supports temporal and frontal lobe dysfunction in ASD. The lack of difference between autism and AS implies that visual memory and sustained attention cannot distinguish these two ASD subtypes, which supports DSM-5 ASD criteria.
In this study, the properties of surface acoustic wave (SAW) filters, including phase velocity and electromechanical coupling coefficient (K2) are investigated. The effective surface permittivity (ESP) method was employed to estimate the K2 of bulk materials (single layer) and multi-layer (double-layer and trilayer) structures. In the cases of bulk materials, the calculation results agree with the experimental data, and the errors are less than 7% for quartz. In the cases of double-layer materials, the phase velocity and K2 of various materials, such as ZnO/Diamond and LiNbO3/Diamond, were acquired, and the results demonstrate that LiNbO3/diamond is the optimal choice for high-frequency SAW devices. For the cases of trilayer, the structure of ZnO/PZT/diamond has relatively high K2 and phase velocity. Therefore, this structure is the optimal trilayer structure for high-frequency SAW devices. The study demonstrates that ESP method can be successfully used for estimating SAW properties in piezoelectric multi-layer structures even though the structures contain nonpiezoelectric film (diamond). The proposed numerical computation has the potential to shorten the developing time of SAW device.
In this study, the fictitious time integration method (FTIM) is applied to investigate wave propagation over an arbitrary bathymetry with measured uncertainty. The FTIM is used to convert the higher-order elliptic mild-slope equation (EMSE) into a FTIM like EMSE (FTIMEMSE). It has the advantage to describe wave transformation from deep water to shallow water region in a large coastal area with numerical efficiency. The validity of the noise resistance for the measured uncertainty of the bathymetry is also studied. In addition, typical examples for waves propagating over an elliptic shoal rest on a horizontal and sloping bottom is presented. It is concluded that the FTIM is robust in the numerical stability and capable of against the noise of the measurement.
In clinical practice, cam-out failure at the recess-screwdriver interfaces may occur when tightening or removing a bone screw. For titanium-based periarticular fixation, the literature reports have revealed that cold welding at the plate-screw interfaces makes the screw recess especially prone to cam-out failure during screw removal. In this study, the effects of the four recess shapes (cross, hexagon, star, and crest), three torque value (0.8, 1.0, and 1.2N-m), and the three interfacial misfits (0.00, 0.05, and 0.10mm) on the cam-out failure were numerically evaluated. The free-rotation angle, torque-recess angle, slippage-resisting length, and interfacial stress distribution were defined and chosen as comparison indices for the twelve recess-misfit variations. The results revealed that the interfacial slippage, torque transfer, and stress distribution are highly related to both recess shape and interfacial misfit. The stresses of all recesses and screwdrivers consistently initiate at the contact sites. However, the recess profile significantly affects the stress propagation. The stress patterns of the recess and screwdriver are quite different between the cross-star and hexagon-crest groups. The cross-star group is superior to the hexagon-crest group in terms of the torque-recess angle and slippage-resisting length over. This makes the recess of the cross-star group less stressed than its counterpart. However, the volumes of the cross and the star screwdriver are more highly stressed than the hexagon due to the irregular shape and the thinner flange, respectively. The greater torque and misfit increase the performance difference between the four recess designs. In conclusion, the geometry of the cross and star groups provide the better performance of the screw recess in terms of torque-transferring efficiency and slippage-resisting ability. If the screwdriver material is properly strengthened and the stress-concentrating corners are modified, the cross and star groups would be the optimal designs that protects and extends the lifetime of both recess and reused screwdriver.
We report production of a self-injected, collimated (8 mrad divergence), 600 pC bunch of electrons with energies up to 350 MeV from a petawatt laser-driven plasma accelerator in a plasma of electron density ne = 1017 cm−3, an order of magnitude lower than previous self-injected laser-plasma accelerators. The energy of the focused drive laser pulse (150 J, 150 fs) was distributed over several hot spots. Simulations show that these hot spots remained independent over a 5 cm interaction length, and produced weakly nonlinear plasma wakes without bubble formation capable of accelerating pre-heated (~1 MeV) plasma electrons up to the observed energies. The required pre-heating is attributed tentatively to pre-pulse interactions with the plasma.
The hydrogenated amorphous silicon (a-Si:H) single-junction thin-film solar cells were fabricated on SnO2:F-coated glasses by plasma-enhanced chemical vapor deposition (PECVD) system. The boron-doped amorphous silicon carbide (a-SiC:H) was served as the window layer (p-layer) and the undoped a-SiC:H was used as a buffer layer (b-layer). The optimization of the p/b/i/n thin-films in a-Si:H solar cells have been carried out and discussed. Considering the effects of light absorption, electron-hole extraction and light-induced degradation, the thicknesses of p, b, n and i layers have been optimized. The optimal a-Si:H thin-film solar cell having an efficiency of 9.46% was achieved, with VOC=906 mV, JSC=14.42 mA/cm2 and FF=72.36%.
Taiwan Photon Source is a new 3-GeV ring with characteristics of great brightness and small emittance, at present under construction at National Synchrotron Radiation Research Center (NSRRC) site in Taiwan and due to be commissioned in 2013. The positioning of the magnets is highly sensitive to alignment errors, and the entire building will be constructed half underground at depth 12 m relative to Taiwan Light Source (TLS) for stability reasons; for these reasons the survey and alignment work is confined and difficult. To position magnets precisely and quickly, a highly accurate auto-tuning girder system combined with a survey network was designed to accomplish the alignment tasks. The survey network includes a preliminary Global Positioning System (GPS) network and a laser-tracking network. The position data from the survey network define a basis for the system of motorized girders to auto-tune and improve the accuracy. The detailed survey and alignment design, simulation and preliminary data are described in this paper.
A precise laser positioning system had been preliminarily developed for the girder system of the Taiwan Photon Source. This laser positioning system, a part of a girder auto-alignment scheme, will be installed on the girders located at both sides of each straight section of the storage ring. The system is composed of a laser and four sets of a position sensing device (PSD). The laser, held on one girder, propagates 13 m along the girder and plays the role of a reference line of girders of the straight section. Based on the laser linear characteristics, the other girder can be adjusted and aligned by a cam mover according to PSD data. To achieve superior precision, the whole laser positioning system should be constructed stably. After making some improvements to eliminate the unstable terms, the precision of the laser positioning system can achieve 2 µm at 13 m propagating distance every 4 h.
Taiwan Photon Source is now under construction at NSRRC Taiwan. In order to maintain the Taiwan Light Source (TLS) for normal operation, a hydrostatic levelling system and precision inclination sensor (Leica Nivel 220) were installed both in the storage ring and beamlines to monitor ground deformation arising. This paper presents the monitoring system setup and the circumstances of ground deformation including vertical settlement and floor inclination during the ground breaking period to provide a criterion for TLS operation.
To investigate the efficacy of intratympanic steroid therapy in adults with sudden sensorineural hearing loss, and to analyse the factors associated with treatment outcome.
Retrospective study of patients undergoing intratympanic steroid injection for sudden sensorineural hearing loss between 1 January 2006 and 30 June 2007 at a teaching hospital in Taipei, Taiwan.
Patients who received intratympanic steroid therapy within seven days of disease onset achieved a significantly better response rate (76.1 per cent), compared with the delayed treatment group (50 per cent). The total response rate, after four steroid injections, was 68.9 per cent. Patients with low and mid-frequency hearing loss were more responsive to steroid treatment. Vertigo was a negative prognostic factor for recovery. There were no long-term sequelae of intratympanic steroid treatment.
Intratympanic steroid injection may be a simple and effective treatment for patients with sudden sensorineural hearing loss.
Taiwan Photon Source (TPS), a new 3 GeV synchrotron ring, is under construction at National Synchrotron Radiation Research Center (NSRRC). To discover problems of design, manufacture and installation, a mockup of 1/24 section (one cell) of TPS was installed at NSRRC. A modified, precise, six-axis, prototype girder system of this mockup composed of three girders was fabricated. We discuss both the installation of the girder system and its diagnostics, and present the results including measurement of the dimensions of the components of the girder system and the vibration tests.
All bacterial isolates from 7058 patients admitted to haemato-oncology wards at National Taiwan University Hospital between 2002 and 2006 were characterized. In total 1307 non-duplicate bloodstream isolates were made from all patients with haematological malignancy; 853 (65%) of these were from neutropenic patients. Gram-negative bacteria predominated (60%) in neutropenic isolates with Escherichia coli (12%), Klebsiella pneumoniae (10%), Acinetobacter calcoaceticus-baumannii complex (6%), and Stenotrophomonas maltophilia (6%) the most frequent. Coagulase-negative staphylococci (19%) and Staphylococcus aureus (4%) were the most common Gram-positive pathogens. Resistance to ciprofloxacin was found in 50% of E. coli and 20% of K. pneumoniae isolates from neutropenic patients. Extensively drug-resistant A. calcoaceticus-baumannii complex and vancomycin-resistant enterococci were also found during the study period. Emerging antimicrobial resistant pathogens are an increasing threat to neutropenic cancer patients.
In this paper, we first fabricate and demonstrate the InGaP/GaAs camel-like gate field-effect transistor with InGaAs pseudomorphic heavy-doped channel. Due to the large gate potential barrier for the use of the n+-GaAs/p+-InGaP/n-GaAs camel-like gate and the thin as well as heavy doping n+-InGaAs channel layer, the effective conduction band discontinuity
is substantially extended and a high gate turn-on voltage up to 2.0 V is obtained. The device exhibits a relatively broad gate voltage swing resulting from the high gate turn-on voltage. In addition, a maximum drain current of 393 mA/mm and a maximum transconductance of 96 mS/mm are measured. These results indicate that the studied device is suitable for signal amplifier and linear circuit applications.
Of 303 children hospitalized with acute non-bloody, non-mucoid diarrhoea, 69 (22·8%) had polymicrobial infection, including 52 (17·2%) multiple viral infection and 17 (5·6%) viral and bacterial co-infection. Rotavirus had the most important role in both categories; thus the control of rotavirus infection is crucial for maintaining children's health in Taiwan.