Search

This paper presents a novel design, optimization and analysis of capacitive radio frequency (RF) micro-electromechanical system (MEMS) switch. The design incorporates a novel membrane and beams' structure with two short high-impedance transmission-line (T-line) sections added on either side of the switch (namely T-match switch) to improve its RF performance, while maintaining low-actuation voltage. The short high-impedance T-line section has narrower width and higher impedance than the coplanar waveguide (CPW)'s signal line, behaves as series inductor to compensate the switch's up-state capacitance and provides excellent matching at the design frequency. This high-impedance T-line section was designed, simulated and optimized using finite-element-modelling (FEM) tool of electromagnetic (EM) simulator of AWR Design EnvironmentTM. The optimized T-line section's width and length is 10 µm and 70 µm, respectively. The RF-MEMS switch is actuated by electrostatic force with low-actuation voltage of 2.9 V, has maximum von Mises stress of 13.208 MPa which is less than aluminium's yield stress and can be operated in robust conditions. Compared to the normal capacitive RF-MEMS switch, this T-match capacitive RF-MEMS switch with two sections of optimized high-impedance T line has improved the performance of return loss and insertion loss, at switch-on state, by 45.83% and 55.35%, respectively; while at the switch-off state, the isolation is increased by 24.05%; only the switch-off return loss is degraded by 11.7% but the value (ź 0.5519 dB) is still located in the range of design specifications. The RF-MEMS switch's actuation time was simulated to be ~ 27 µs with amplitude of 5 V up-step voltage.

This paper presents the design, optimization and simulation of a radio frequency (RF) micro-electromechanical system (MEMS) switch. The capacitive RF-MEMS switch is electrostatically actuated. The structure contains a coplanar waveguide, a big suspended membrane, four folded beams to support the membrane and four straight beams to provide the bias voltage. The switch is designed in standard 0.35 µm complementary metal oxide semiconductor process and has a very low pull-in voltage of 3.04 V. Taguchi method and weighted principal component analysis is employed to optimize the geometric parameters of the beams, in order to obtain a low spring constant, low pull-in voltage, and a robust design. The optimized parameters were obtained as w = 2.5 µm, L1 = 30 µm, L2 = 30 µm and L3 = 65 µm. The mechanical and electrical behaviours of the RF-MEMS switch were simulated by the finite element modeling in software of COMSOL Multiphysics 4.3® and IntelliSuite v8.7®. RF performance of the switch was obtained by simulation results, which are insertion loss of ?5.65 dB and isolation of ?24.38 dB at 40 GHz.

There is a paradox experienced by manufacturing firms attempting to servitize that their substantial investment in adding services to the existing product portfolio does not bring expected higher returns. The purposes of this paper are to gain more understanding as to the servitization status in Zhejiang Province of China and the influence of servitization on business performance of manufacturers. We conduct a regression analysis based on 134 listed manufacturing firms in 12 sectors in Zhejiang Province of China in 2012. Our results show that there is a significant positive relationship between servitization and business performance for manufacturing firms in Zhejiang; a U-shape relationship between servitization and profit per capita of firms is identified. In addition, the strategy of servitization is more suitable for larger firms and the effect of servitization in boosting business performance becomes more prominent once servitization has grown beyond certain threshold.

Several multi-cell improvement methods for solving existing problems of conventional T-shaped concrete-filled steel tubular (T-CFST) columns and for determining steel׳s optimal distributions for increasing the strength and ductility of the columns are presented. An experimental study with eight multi-cell T-shaped concrete-filled steel tubular (MT-CFST) columns and one conventional T-CFST column under low frequency cyclic loading was conducted. Effects of the multi-cell layout and the concrete strength on the hysteretic behavior of the specimens were investigated. Experimental results showed that the lateral load-displacement hysteretic curves of the columns were generally saturated with a slight pinching effect. Owing to the asymmetry of the T-shaped cross section, the hysteretic behavior of the composite columns is asymmetrical in different loading directions. The improved MT-CFST columns showed better seismic behavior due to high load bearing capacity, ductility and energy dissipation capacity. Furthermore, the non-linear finite element analysis was performed to simulate the hysteretic behavior of the specimens and the numerical results agreed well with the test results. In conclusion, with an increasing axial load ratio, the ultimate lateral load in the pushing direction gradually decreases and is reached earlier, whereas the ultimate lateral load in the pulling direction increases slightly under low axial ratio and decreases under high axial load ratio.

A low-voltage low-loss K-band 3-bit MEMS switched-line phase shifter is presented in this work. The phase shifter is constructed by novel shunt capacitive RF-MEMS switches and coplanar waveguide lines on a high-resistivity silicon substrate. A low-voltage RF-MEMS switch (pull-in voltage = 3.04V) is employed and exhibits good RF characteristics by using T-match technique where its insertion loss and isolation is −0.1291dB and −28.75dB, respectively at frequency of 20GHz. The 3-bit MEMS phase shifter is assembled by three single-bit units (namely, 45°-bit, 90°-bit and 180°-bit) of switched-line structures; the average phase error and average insertion loss is 0.2445° and −2.447dB, respectively, at 20GHz; its return loss is better than 10dB at a wideband frequency range of up to 20GHz. The whole design area is 6mm∗4mm.

Purpose – This paper provides a comprehensive assessment of the influencing factors on knowledge transfer through meta-analysis with an emphasis on the influence of cultural contexts. Design/methodology/approach – The approach involved the evaluation and analysis of 69 published empirical studies and the categorization of these studies into two groups based on different cultural contexts as described by Hofstede. A meta-analytic approach was then employed to provide a comparative analysis of the categorized studies. Findings – The results of the meta-analysis of the influencing factors of knowledge transfer are consistent with the results obtained in most previous studies, indicating a maturation of research in this area. Influencing factors such as knowledge ambiguity, tie strength, trust, and common cognition are shown to impact knowledge transfer in different cultural contexts, particularly with regard to the individualism-low power distance and collectivism-high power distance dimensions defined by Hofstede. Research limitations/implications – This analysis was limited to the correlation between the influencing factors and the general performance in knowledge transfer and did not specifically address more detailed dimensions such as efficiency and effectiveness. In addition, this analysis was restricted to the cultural contexts of only two cultural dimensions. However, the review of this broad range of studies provided sufficient data to allow an in-depth analysis of related influencing factors and helped to illustrate and exemplify the influencing mechanisms of culture on knowledge transfer. Practical implications – The results presented in this paper can help managers working in cross-cultural environments to understand the key influencing factors that affect knowledge transfer in the workplace. By understanding these factors, managers can more effectively implement methods and procedures that improve cross-cultural knowledge transfer in the work environment. Originality/value – This paper provides a detailed insight into the influencing factors found between two distinctive cultural contexts and offers a fresh analysis of influencing factors with regard to knowledge transfer in a cross-cultural environment.

Mode of tax policy since the implementation of the Shanghai free trade zone established based on replicable features, combined with the Heilongjiang economic and trade development is particularly urgent requirement to build regional free trade zone border, by analogy analysis, judgment and reasoning methods, analysis of Heilongjiang Province trade development problems and cause, tax policy and the characteristics of Shanghai FTA are reviewed. And from the trade environment demand, trade location adaptability, economic development of domestic power and related policy supporting mechanism sound level, demonstrates the feasibility of Heilongjiang province Shanghai FTA copy tax policy.

Acute lower respiratory tract infection (ALRI) due to adenovirus infection is a low frequency event but often causes severe outcome. This study was undertaken to uncover the clinical and epidemiological features of adenovirus infection in children.Hospitalized children with ALRI were analyzed through continuous monitoring from 2006 to 2012. Nasopharyngeal aspirates were examined by direct immunofluorescence to detect respiratory agents including respiratory syncytial virus, adenovirus, influenza virus types A/B, parainfluenza virus types 1/2/3. Chlamydia pneumonia, Mycoplasma pneumonia and Chlamydia trachomatis were determined by real-time PCR. A retrospective analysis was made of 479 patients with positive infection of adenovirus.The positive detection rate of adenovirus was 0.63% in patients with ALRI. The incidence rate of adenovirus-associated acute lower respiratory tract infection peaked at the second six months of life. The morbidity was much higher in winter, spring and summer than in autumn. Patients with pneumonia accounted for 73.90% of the patients. More than one-third of the patients developed severe pneumonia, whereas no death was found. Features of severe adenovirus-associated lower respiratory tract infection included persistent high fever with serious infective symptoms, and hepatic dysfunction was one of the most common complications. Mixed infection of atypical pathogens was common (18.58%) in this study.Adenovirus is a critical pathogen that can cause severe respiratory infections even in immunocompetent children. Coinfection of adenovirus with atypical pathogens is common. Antibiotic treatment with azithromycin or erythromycin is necessary in patients with mixed infection of atypical pathogens.

This paper presents a novel design and analysis of capacitive radio frequency (RF) micro-electromechanical system (MEMS) switch. The RF-MEMS switch is actuated by electrostatic force with low-actuation voltage of 2.9V while it can be operated in a robust condition with maximum von Mises stress of 13.208 MPa which is less than aluminum's yield stress. By finite-element-modeling (FEM) simulations, at switch-on state, insertion loss and reflection loss of the proposed RF-MEMS switch is obtained as −0.8023dB and −7.983dB, respectively; and at switch-off state, isolation and return loss is −22.45dB and − 0.8666dB, respectively. In order to improve the switch-on reflection loss to meet design specifications, two short high-impedance sections of transmission line have been calculated and added to the RF-MEMS switch. Then the reflection coefficient at switch-on state has been increased by 78.13% to −14.22dB which is less than −10dB while the insertion loss, isolation and return loss are all improved by 66.54%, 13.36% and 11.65%, respectively, with 65ohm high-impedance lines. The RF-MEMS switch's actuation time of 27µs is obtained. A detail comparison among the proposed RF-MEMS switch and other state-of-the-art designs has been summarized in the end.

This study aimed to explore whether antenatal supplement of taurine can improve the brain development of fetal rats with intrauterine growth restriction (IUGR) via protein kinase A (PKA)-Ca(2+)/calmodulin-dependent protein kinase II (CaMKII)/c-fos pathway. A total of 30 pregnant rats were randomly divided into the following three groups: control, IUGR, and IUGR with antenatal taurine supplementation groups. The expression of PKA, CaMKII, and c-fos mRNA and proteins in fetal rat brain tissues were detected by quantitative real time (qRT)-polymerase chain reaction (PCR) and Western blot, respectively; and the number of PKA-, CaMKII- and c-fos-positive cells was measured by immunohistochemistry. Western blot and qRT-PCR revealed that antenatal taurine supplementation significantly increased PKA, CaMKII, and c-fos protein and mRNA levels in fetal rats brain with IUGR (p < 0.05). Immunohistochemistry results showed that the numbers of PKA-, CaMKII-, and c-fos-positive cells were significantly decreased in the IUGR groups compared with the controls; while antenatal taurine could significantly increase the positive cell numbers (p < 0.05). So, we conclude that antenatal taurine improves IUGR fetal brain development which is associated with increasing the activity of PKA-CaMKII/c-fos signal pathway.

The effect of time from diagnosis to treatment (TDT) on overall survival of patients with acute myeloid leukemia (AML) remain obscure. Furthermore, whether chemotherapy delay impacts overall survival (OS) of patients with a special molecular subtype has not been investigated. Here, we enrolled 364 cases of AML to assess the effect of TDT on OS by fractional polynomial regression in the context of clinical parameters and genes of FLT3 ITD, NPM1, CEBPA, DNMT3a, and IDH1/2 mutations. Results of the current study show IDH1/2 mutations are associated with older age, M0 morphology, an intermediate cytogenetic risk group, and NPM1 mutations. TDT associates with OS for AML patients in a nonlinear pattern with a J shape. Moreover, adverse effect of delayed treatment on OS was observed in patients with IDH1/2 mutations, but not in those with IDH1/2 wild type. Therefore, initiating chemotherapy as soon as possible after diagnosis might be a potential strategy to improve OS in AML patients with IDH1/2 mutations. Disclosures No relevant conflicts of interest to declare.

Long-term room-temperature annealing effects of InGaAs/InP quantum wells with different wells (namely triple wells and five wells embedded) and bulk InGaAs are investigated after high energy electron irradiation. It is observed that the photoluminescence (PL) intensity of bulk InGaAs materials is enhanced after low dose electron irradiation and the PL intensity for all the three samples is degraded dramatically when the electron dose is relatively high. With respect to the room-temperature annealing, we find that the PL intensity for both samples recovers relatively fast at the initial stage. The PL performance of multiple quantum-well samples shows better recovery after irradiation compared with the results of bulk InGaAs materials. Meanwhile, the recovery speed factors of multiple quantum-well samples are relatively faster than those of the bulk InGaAs materials as well. We infer that the recovery difference between the quantum-well materials and bulk materials originates from the fact that the radiation induced defects are confined in the quantum wells as a consequence of the free energy barrier between the In0.53Ga0.47As wells and InP barrier layers.