bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new pilot design for NC‐OFDM systems under power constraints
Authors: Zhu Chun‐hua , Yang Jing , Yang Shou‐yi 
Published: November 2013

ABSTRACTThe pilot design is one of the key issues that has to be solved in order to improve the performance of non‐continuous orthogonal frequency division multiplexing (NC‐OFDM) systems in cognitive radio context. Equally‐spaced and equally‐powered pilot tones that are the optimal pilot design for conventional OFDM systems cannot be applicable to NC‐OFDM systems with the non‐continuous(NC) spectrum. In NC‐OFDM systems, the secondary users(SUs) communicate to each other by spectrum mapping the primary users(PUs)’ band to protect the PUs from interference. So the SUs’ available subcarriers’ positions and power allocation will be changed with PUs’ active state and interference constraints. The NC available spectrum and power distribution bring new challenges on system design, which make the pattern of pilots in the frequency domain vulnerable. Several recent researches have studied the optimal or suboptimal pilot designs under equally‐powered assumption. In this paper, we only focus on the comb‐type pilot design under uneven power distribution hypothesis for the NC‐OFDM transmission. Firstly, based on maximising each available subcarrier’ power under PUs’ interference temperature constraints, the pilot power constraints have been discussed, then the formula between pilot positions and pilot powers have been derived by minimising the channel estimation mean square error; moreover, a suboptimal pilot design under the pilot power constraints is also presented. The proposed pilot design cannot only obtain better channel estimation performance compared with previous pilot designs, but also consider the PUs’ communication reliability. Simulation results demonstrate the effectiveness of the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.
Human platelet‐rich plasma induces chondrogenic differentiation of subchondral progenitor cells in polyglycolic acid–hyaluronan scaffolds
Authors: Krüger Jan Philipp , Ketzmar Anna‐Katharina , Endres Michaela , Pruss Axel , Siclari Alberto , Kaps Christian 
Published: November 2013

AbstractCartilage repair approaches may be improved by addition of human platelet‐rich plasma (PRP) that increases chondrogenic differentiation of mesenchymal stem and progenitor cells. The aim of our study was to evaluate the effect of human PRP on the differentiation of multipotent human subchondral progenitor cells in resorbable polyglycolic acid–hyaluronan (PGA‐HA) scaffolds. PGA‐HA scaffolds were loaded with subchondral progenitor cells and stimulated with transforming growth factor‐beta3 (TGFB3) or 5% PRP, whereas nonstimulated cultures served as controls. Chondrogenic differentiation was evaluated by real‐time gene expression analysis of typical chondrogenic marker genes and by immunohistochemical staining of extracellular cartilage matrix molecules such as proteoglycans and collagen type II. TGFB3 and PRP induced the expression of chondrogenic marker genes collagen type II and IX, aggrecan, and cartilage oligomeric matrix protein in subchondral progenitor cells cultured in PGA‐HA scaffolds compared with nonstimulated controls. Progenitor cells in PGA‐HA scaffolds formed an extracellular matrix rich in proteoglycans and collagen type II on treatment with PRP, but to a lesser extent, than in cultures stimulated with TGFB3. The results suggest that PRP induces chondrogenic differentiation of progenitor cells in PGA‐HA scaffolds and may be therefore beneficial in scaffold‐assisted cartilage repair approaches involving stem and progenitor cells. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 681–692, 2014.
Photoinduced Atom Transfer Radical Polymerization Using Semiconductor Nanoparticles
Authors: Dadashi‐Silab Sajjad , Atilla Tasdelen Mehmet , Mohamed Asiri Abdullah , Bahadar Khan Sher , Yagci Yusuf 
Published: November 2013

Photoinduced atom transfer radical polymerization of methyl methacrylate initiated by in situ generation of copper (I) complex from higher oxidation state species using neat zinc oxide and iron‐doped zinc oxide nanoparticles is investigated. The polymerizations proceed in a well‐controlled manner under UV light at room temperature as evidenced by kinetic and light on–off experiments. The evolution of molecular weight with conversion shows good correlations between experimental and theoretical molecular weights, which confirmed good control over polymerization along with a narrow molecular weight distribution.
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The design of waveguide filters based on cross‐coupled resonators
Authors: Shang Xiaobang , Xia Wenlin , Lancaster Michael J. 
Published: November 2013

ABSTRACTThis article addresses the physical realization of crosscoupled waveguide filters based on electromagnetic (EM) simulations. For this design procedure, the filter structure is simulated by successively adding one resonator at a time. The desired filter response is achieved without the need of a global optimisation on all the mechanical dimensions within an EM simulator. This reduces the design time required for a crosscoupled waveguide filter and allows the possibility of building high‐order waveguide filters with complex crosscouplings. A sixth order X‐band dual‐band filter with a center frequency of 10 GHz and a fractional bandwidth of 1% is designed using this procedure and presented here as an example. Excellent agreement between simulation results and theoretical results from coupling matrix verifies the proposed approach. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:3–8, 2014
Four‐port balanced antenna feeding network for switchable polarizations and stable Tx/Rx isolation characteristics
Authors: Lee Han‐Lim , Park Dong‐Hoon , Tae Hyun‐Sung , Lee Moon‐Que , Yu Jong‐Won 
Published: November 2013

ABSTRACTA new four‐port balanced antenna feeding network for switchable polarizations and high transmit/receive (Tx/Rx) isolation characteristics is presented. The proposed structure is configured by two switching mode hybrid matrices which consist of two 3‐dB couplers and two SP4T switches, two directional couplers, and Wilkinson dividers. By controlling impedances of the switching mode hybrid matrices, different types of polarizations such as right‐handed circular polarization, left‐handed circular polarization, vertical polarization, and horizontal polarization can be generated with stable Tx/Rx isolation characteristics regardless of antenna impedance variations. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:17–23, 2014
Design of a multipolarization reconfigurable microstrip array antenna using PIN diodes
Authors: Song Taeho , Woo Seungmin , Park Daesung , Lee Seokgon , Choi Jaehoon 
Published: November 2013

ABSTRACTA multipolarization reconfigurable microstrip array antenna that can be used selectively for four polarizations [vertical polarization (VP), horizontal polarization (HP), right hand circular polarization (RHCP), left hand circular polarization (LHCP)] at the S‐band is proposed. To control the four polarization states, a single element consisting of four PIN diodes and a microstrip patch with a circular slot is need. The fabricated array antenna has a VSWR below 2 from 3.32 to 3.39 GHz for VP, from 3.30 to 3.375 GHz for HP, from 3.285 to 3.405 GHz for LHCP, and from 3.27 to 3.40 GHz for RHCP. The 3‐dB axial ratio bandwidth is wider than 19 MHz in the circular polarization states, and the cross‐polarization levels are higher than −20 dB in the linear polarization and −17 dB in the circular polarization, respectively. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:104–110, 2014
V‐band GaAs low LO power driven double‐balanced Gilbert mixer based on dual‐meandering baluns design
Authors: Ke P. Y. , Huang F. H. , Kao H. L. , Chiu Hsien‐Chin 
Published: November 2013

ABSTRACTA low local oscillator (LO)‐power, V‐Band MMIC down‐conversion, double‐balanced Gilbert mixer with integrated RF and LO baluns is designed and fabricated using standard 0.15‐µm pHEMT MMIC technology and characterized using probe measurements. There is a high conversion gain at a low‐LO power level. This enables the proposed “current bleeding resistor divider voltage” technique, also provided in the Gilbert‐cell mixer, to boost the conversion gain at a low–LO power level. The greatest conversion gain is from 5.17 to 1.41 dB at an RF frequency 53–60 GHz, and a Pub of −9.5 dBm at an LO input power of −7 dBm. Both RF‐LO and LO‐RF isolations are better than 25 dB. This is believed to be the lowest‐LO power and highest conversion gain so far achieved for V‐band mixers. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:60–64, 2014
size reduction of rectangular microstrip antenna
Authors: Neogi Shatarupa , Bhattacharjee Anup K. , Pratim Sarkar Partha 
Published: November 2013

ABSTRACTA novel compact asymmetric‐slotted‐slit‐rectangular microstrip patch antenna coaxially fed is proposed. The antenna provides resonating frequency at 6.06 and 6.45 GHz providing approximately 66.33% size reduction compared to an ordinary microstrip patch antenna. Further the antenna has been modified to resonate at a frequency of 4.66 GHz, providing approximately a size reduction of 80.22%. A good agreement between simulated and measured results is obtained. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:244–248, 2014
Design of a dual‐polarized small base station antenna with metallic cube for beyond 4G systems
Authors: Lee Jung N. , Kwon Heon K. , Kang Byung S. , Lee Kwang C. 
Published: November 2013

ABSTRACTIn this article, a small base station antenna for beyond 4G systems is proposed. The proposed antenna is composed of two metallic dipole elements, two feed plates, an FR‐4 substrate, an aluminum cube, and a radome. The measured −10 dB impedance bandwidth is 2.45–2.9 GHz. The proposed antenna has an isolation of greater than 30 dB at operating frequencies. The measured average antenna gain is 5.5 dBi, and the cross polarizations are all less than 20 dB below the copolarization value. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:91–96, 2014
Frequency‐reconfigurable dual‐band monopole antenna for WiMAX wireless devices
Authors: Sun X. L. , Cheung S. W. , Yuk T. I. 
Published: November 2013

ABSTRACTThis article proposes a planar monopole antenna with two frequency‐tunable bands for wireless devices used in the WiMAX system. The antenna has two radiating branches acting as monopoles and resonating at around 2.4 GHz (lower band) and 3.4 GHz (higher band). By using two varactors on the radiating branches with novel designs of DC‐biasing circuits, the two operating bands can be continuously tuned using the corresponding DC‐bias voltages. The lower band can be tuned to cover the frequency bands of 2.3–2.4 GHz and 2.5–2.69 GHz, and the higher band can cover the frequency bands of 3.3–3.4 GHz, 3.4–3.6 GHz, and 3.6–3.8 GHz for the WiMAX system. The antenna has a small overall size of 40 × 35 × 0.8 mm3 with a compact radiator of only 14.5 × 8.2 mm2. The antenna performance in terms of tuning, reflection coefficient, radiation pattern, efficiency, and peak gain are studied using computer simulation. For verification of simulation results, the antenna is fabricated and measured. The feeding cable used in measurement causes substantial discrepancies between the simulated and measured results. To study the cable effects, a computer model for the cable is included for simulation studies. With the cable model, the simulated and measured results agree very well. Although the WiMAX system is used in our design, the proposed tuning technique may well be used for tuning other frequency bands in different standards. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:49–55, 2014
X‐band MMIC low‐noise amplifier MMIC on SiC substrate using 0.25‐μm ALGaN/GaN HEMT technology
Authors: Chang Woojin , Jeon Gye‐Ik , Park Young‐Rak , Mun Jae‐Kyoung 
Published: November 2013

ABSTRACTIn this article, we demonstrate a 9.7–12.9‐GHz monolithic microwave integrated circuit low‐noise amplifier (LNA) designed and fabricated using a AlGaN/GaN 0.25‐µm high‐electron mobility transistor on silicon carbide (SiC) technology. Microstriplines are used for matching circuits, except for the MIM capacitors acting as DC blocks in the matching circuits of the LNA circuit. The matching and bias circuits of the LNA are merged and meandered to simplify the structure of the amplifier and reduce the chip size. The LNA shows a noise figure of 1.7–2.1 dB with a small‐signal gain of 20–26 dB and an isolation of 45–52 dB across the 9.7–12.9 GHz frequency range. Under continuous wave conditions, a saturated output power of 34 dBm is shown at 11.2 GHz, and an output third‐order intercept point of 42 dBm is also achieved at 11.4 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:96–99, 2014
Polarization‐reconfigurable microstrip antenna with a fixed frequency band using a single switch
Authors: Park Wook‐Ki , Oh Soon‐Soo , Shafai Lotfollah 
Published: November 2013

ABSTRACTThis article proposes a reconfigurable microstrip antenna that changes its polarization with only a single switch at a single frequency band. The antenna consists primarily of a square ring and a square patch, with a foam layer. When the connection status between the square ring and the ground is changed between shorted and open status, the linear polarizations are switched. The resonant frequency of the antenna using a single switch reported previously has been shifted, but the proposed antenna in this article exhibits a fixed resonant frequency. The design principle is as follows: The square‐ring printed on the dielectric substrate has inherent narrow bandwidth, but we found that its polarization‐switching characteristics existed over the broad band. The square patch is placed above the square ring, and it provides a broad bandwidth while maintaining polarization diversity. The performance of the antenna is successfully demonstrated via simulation and measurement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:57–60, 2014
Compact UWB monopole antenna with enhanced bandwidth using rotated L‐shaped slots and parasitic structures
Authors: Ojaroudi Nasser 
Published: November 2013

ABSTRACTIn this article, a new design of compact ultrawideband (UWB) monopole antenna is presented .The antenna consists of a ordinary square radiating patch and a ground plane with pairs of rotated L‐shaped slots and parasitic structures. By cutting a pair of rotated L‐shaped slots and also by embedding a pair of rotate L‐shaped conductor‐backed plane in air gap distance, additional resonances are excited and much wider impedance bandwidth can be produced. Also, the usable upper frequency of the antenna is extended from 10.3 to 18.31 GHz. Simulated and measured results show that the antenna design exhibits an operating bandwidth (VSWR < 2) from 3.09 to 18.31 GHz which provides a wide usable fractional bandwidth of more than 140%. The proposed antenna has an ordinary square radiating patch, therefore, displays a good omnidirectional radiation pattern even at higher frequencies. The antenna configuration is simple, easy to fabricate, and can be integrated into UWB systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:175–178, 2014
A study of transmission of RF signal with single conductor wire
Authors: Mei Zicong , Yeung Sai Ho , Sarkar Tapan K. , Salazar‐Palma Magdalena 
Published: November 2013

ABSTRACTSome researches showed that a single conductor wire can transmit signals. We tried to duplicate these results and we can see a single conductor wire does transmit signals. But its performance is very poor, especially when the wire is not a straight wire. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:124–127, 2014
Design and fabrication of a combined three‐layer coating including gradient refractive index films for broadband antireflection on silicon
Authors: Hu Junjie , Ge Zhongyang , Piquette Alan , Mishra Kailash , Klotzkin David 
Published: November 2013

ABSTRACTA three‐layer antireflective coating, including a gradient index layer, was designed using numerical optimization and fabricated with cosputtering on a silicon substrate. The average reflectivity of Si was reduced from ∼35 to ∼4% after coating. These multilayer coatings can significantly improve performance devices which need to absorb or emit light. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:256–259, 2014
High selectivity band pass filters on iso/anisotropic dielectric, ferrimagnetic, and metamaterial substrates
Authors: Silva Neto Valdemir P. , Vasconcelos Cristhianne F. L. , Albuquerque Maria Rosa M. L. , D'Assunção Adaildo G. 
Published: November 2013

ABSTRACTThis work describes a frequency response investigation of a band pass microstrip filter geometry printed on different substrate materials. The filter geometry comprises a wavelength rectangular ring resonator that is side coupled to two quarter‐wavelength lines to provide the access ports. This filter geometry is particularly suitable for high‐frequency selective applications. The investigation of the properties of the filter geometry is carried out for iso/anisotropic dielectric, ferrimagnetic, and metamaterial substrates, for comparison purpose. Simulation and design are performed using Ansoft HFSS, a commercial software based on the accurate finite element method. Resonant frequency, return loss, insertion loss, and percent bandwidth results are compared and discussed, taking into account the effect produced by each material substrate on the filter performance. Prototypes of band pass filters on isotropic substrates are built and measured. Simulated and measured results are in agreement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:201–206, 2014
Evaluations of extracellular pH within in vivo tumors using acidoCEST MRI
Authors: Chen Liu Qi , Howison Christine M. , Jeffery Justin J. , Robey Ian F. , Kuo Phillip H. , Pagel Mark D. 
Published: November 2013

PurposeA practical, noninvasive method is needed to measure the extracellular pH (pHe) within in vivo tumors to longitudinally monitor tumor acidosis. We have optimized a biomedical imaging method, termed acidoCEST MRI, to provide noninvasive assessments of tumor pHe in preclinical models of mammary carcinoma.MethodsA CEST‐FISP MRI method was optimized to detect the chemical exchange saturation transfer (CEST) of two amide protons of a clinically approved CT contrast agent, iopromide. The ratio of the two CEST effects was used to measure pH. Routes of administration of iopromide were evaluated to ensure sufficient delivery of the agent to the tumor. The optimized acidoCEST MRI method was then used to evaluate the change in tumor pHe following alkalinizing bicarbonate treatment.ResultsThe acidoCEST MRI protocol measured pH between 6.2 and 7.2 pH units. Greater delivery of iopromide was shown to improve the precision of the measurement of tumor pHe, but the agent did not influence the tumor pHe. AcidoCEST MRI was used to longitudinally monitor the effect of bicarbonate treatment on the pHe of tumors and bladders.ConclusionThis study demonstrates that an optimized acidoCEST MRI method is a practical, noninvasive method for assessing changes in tumor acidosis. Magn Reson Med 72:1408–1417, 2014. © 2013 Wiley Periodicals, Inc.
Increased burden on caregivers of having a child with haemophilia complicated by inhibitors
Authors: Lindvall Karin , von Mackensen Sylvia , Elmståhl Sölve , Khair Kate , Stain Ann Marie , Ljung Rolf , Berntorp Erik 
Published: November 2013

IntroductionHaving a child with a chronic disease often increases the burden in the family with more hospital visits, treatment administration, and increased worries for the ill child. A cross‐sectional, international, multi‐centre study in caregivers of children <18 years with haemophilia and inhibitor was performed at Haemophilia Treatment Centres in Sweden, UK, and Canada to evaluate caregivers' burden and their health‐related quality of life (HRQoL) compared to that of caregivers of children on prophylaxis without inhibitors and caregivers of healthy children.MethodsCaregivers of children with haemophilia completed several questionnaires (SF‐36, Visual Analogue Scale of Interference (VAS), Caregivers' Burden Scale and Impact on Family Scale (IOF). Caregivers of healthy children completed only the SF‐36. In addition, socio‐demographic data were collected.ResultsIn total, 143 caregivers were included in the study. Comparing the two haemophilia groups with caregivers of healthy children revealed significant differences for all SF‐34 domains except ‘pain’ and ‘general health’. In Caregivers' Burden Scale, caregivers of children with inhibitors reported higher impact of haemophilia (P < 0.0001) and higher impact on VAS (P < 0.0001) compared to caregivers of children without inhibitors. In IOF, caregivers of children with inhibitors reported significant negative impact of the disease, except for aspect of coping.ConclusionCaregivers of children with inhibitors reported higher impact of the disease compared to caregivers of children with no inhibitors. No differences between mothers and fathers in the two groups for SF‐36, Caregivers' Burden Scale, VAS and IOF, except for domain pain in SF‐36 where mothers reported higher impairments. Pediatr Blood Cancer 2014;61:706–711. © 2013 Wiley Periodicals, Inc.
Dissipation rate of thiacloprid and its control effect against Bemisia tabaci in greenhouse tomato after soil application
Authors: Dong Sa , Qiao Kang , Wang Hongyan , Zhu Yukun , Xia Xiaoming , Wang Kaiyun 
Published: November 2013

AbstractBACKGROUNDThiacloprid is a chloronicotinyl insecticide that is quite effective against sucking insects. In this study, when thiacloprid was applied at two different rates (normal rate 15 kg ha−1, double rate 30 kg ha−1), the systemic distribution and residue of thiacloprid as well as its control effect against whitefly (Bemisia tabaci) were investigated in greenhouse tomato after soil application.RESULTSThe results showed that thiacloprid was present in the tomato leaves until day 25, and then its amount was less than 0.005 mg kg−1 and could not be detected. Thiacloprid residue in the tomato stems basically remained at a stable low level throughout the experimental period. Thiacloprid in soil had half‐lives of 11.8 and 12.5 days for the normal treatment and the double treatment respectively. The control efficiency of whiteflies was about 90% from day 1 to day 10. This was followed by a slow decline, but efficiency was still higher than 50% until day 21. In addition, no significant differences were noted in the control effect of thiacloprid on whiteflies between the two different rates.CONCLUSIONSoil application of thiacloprid at the normal rate can effectively control whiteflies, with high efficiency and long persistence. © 2013 Society of Chemical Industry