bluuebunny/crossref_metadata_2025 huggingface dataset:
Verification of the GUMICS‐4 global MHD code using empirical relationships
Authors: Gordeev E. , Facskó G. , Sergeev V. , Honkonen I. , Palmroth M. , Janhunen P. , Milan S.
Published: May 2013

Global magnetohydrodynamic (MHD) modeling is a powerful tool in space physics research. There are several advanced and still developing global MHD codes that are widely used to simulate plasma processes in solar wind magnetosphere‐ionosphere system. The verification of global simulation codes is an important but a difficult problem. We present an approach for systematic and quantitative testing of code performance based on statistical empirical dependencies of the key magnetospheric parameters obtained from observations. We demonstrate the applicability of the method by testing the Grand Unified Magnetosphere Ionosphere Coupling simulation (GUMICS‐4) global MHD model. A large set of nearly stationary solutions (162 runs altogether) with different stationary interplanetary magnetic field (IMF) and solar wind inputs were generated for different dipole tilts and levels of solar EUV radiation. As key parameters, we use the large‐scale characteristics of the magnetosphere, including the magnetopause size and shape, geometry of the tail neutral sheet, magnetotail plasma pressure, tail lobe magnetic field, and cross‐polar cap electric potential. We found that the GUMICS‐4 stationary solutions generally fit the statistical relations, however, with some discrepancies. Particularly, position of the subsolar magnetopause, neutral sheet shape and position, and the plasma sheet pressure during northward IMF agree well with statistical models. At the same time, the size of the tail magnetopause and the lobe magnetic field magnitude appear to be systematically lower compared to their empirical values. Furthermore, the ionospheric potential is smaller in magnitude compared to empirical relations. These results provide an important starting point in the further development of the GUMICS simulation.
Ensuring repeatability and robustness of poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) HPLC monolithic columns of 3 mm id through covalent bonding to the column wall
Authors: Laaniste Asko , Kruve Anneli , Leito Ivo
Published: May 2013

Two different methods to reinforce the poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) HPLC monolithic columns of 3 mm id in a glass column reservoir were studied: composite columns with polymeric particles in the monolith and surface treatment of the reservoir wall. Of the two methods used to counter the mechanical instability and formation of flow channels (composite columns and column wall surface treatment), we demonstrated that proper column wall surface treatment was sufficient to solve both problems. Our study also indicated that no surface treatment is efficient, and of the methods studied silanization in acidified ethanol solution and constant renewal of the reaction mixture (dynamic mode) proved to be the most effective. As a result of this study, we have been able to prepare repeatable and durable methacrylate HPLC columns with good efficiencies.
Nefness of adjoint bundles for ample vector bundles of corank 3
Authors: Tironi Andrea L.
Published: May 2013

Let be an ample vector bundle of rank on a smooth complex projective variety X of dimension n. The aim of this paper is to describe the structure of pairs as above whose adjoint bundles are not nef for . Furthermore, we give some immediate consequences of this result in adjunction theory.
Covers of elliptic curves with unique, totally ramified branch points
Authors: Rubinstein‐Salzedo Simon
Published: May 2013

A well‐known and difficult problem in computational number theory and algebraic geometry is to write down equations for branched covers of algebraic curves with specified monodromy type. In this article, we present a technique for computing such covers in the case of covers of elliptic curves with unique, totally ramified branch points.
Changes in endolysosomal enzyme activities in cerebrospinal fluid of patients with Parkinson's disease
Authors: van Dijk Karin D. , Persichetti Emanuele , Chiasserini Davide , Eusebi Paolo , Beccari Tommaso , Calabresi Paolo , Berendse Henk W. , Parnetti Lucilla , van de Berg Wilma D. J.
Published: May 2013

Parkinson's disease (PD) is characterized neuropathologically by the cytoplasmic accumulation of misfolded α‐synuclein in specific brain regions. The endolysosomal pathway appears to be involved in α‐synuclein degradation and, thus, may be relevant to PD pathogenesis. This assumption is further strengthened by the association between PD and mutations in the gene encoding for the lysosomal hydrolase glucocerebrosidase. The objective of the present study was to determine whether endolysosomal enzyme activities in cerebrospinal fluid (CSF) differ between PD patients and healthy controls. Activity levels of 6 lysosomal enzymes (β‐hexosaminidase, α‐fucosidase, β‐mannosidase, β‐galactosidase, β‐glucocerebrosidase, and cathepsin D) and 1 endosomal enzyme (cathepsin E) were measured in CSF from 58 patients with PD (Hoehn and Yahr stages 1–3) and 52 age‐matched healthy controls. Enzyme activity levels were normalized against total protein levels. Normalized cathepsin E and β‐galactosidase activity levels were significantly higher in PD patients compared with controls, whereas normalized α‐fucosidase activity was reduced. Other endolysosomal enzyme activity levels, including β‐glucocerebrosidase activity, did not differ significantly between PD patients and controls. A combination of normalized α‐fucosidase and β‐galactosidase discriminated best between PD patients and controls with sensitivity and specificity values of 63%. In conclusion, the activity of a number of endolysosomal enzymes is changed in CSF from PD patients compared with healthy controls, supporting the alleged role of the endolysosomal pathway in PD pathogenesis. The usefulness of CSF endolysosomal enzyme activity levels as PD biomarkers, either alone or in combination with other markers, remains to be established in future studies. © 2013 Movement Disorder Society
Posterior thigh perforator flaps: An anatomical study to localize and classify posterior thigh perforators
Authors: Hupkens Pieter , Ozturk Ekin , Wittens Sabine , Hoevenaren Ingrid A. , Kooloos Jan G.M. , Ulrich Dietmar J.O.
Published: May 2013

In the last decade perforator flaps have been used increasingly for different indications. Many regions may serve as donor site. In this respect the posterior thigh region (PTR) has been neglected as a potential donor site for many years. The purpose of this study was to provide complete mapping of perforators supplying the posterior thigh region. Twelve fresh cadaver thighs were prepared injecting diluted acrylic paint into the iliac artery. Thereafter the posterior thighs were dissected from medial to lateral, distinguishing the perforators at the level of the superficial fascia. The perforators were localized and origin, source, length and diameter of the perforators were documented. Analysis occurred using ANOVA and the two proportion Z test. The distribution of musculocutaneous and septocutaneous perforators was respectively 69.1% and 30.9% (P = 0.002). The PTR was divided in thirds. Most perforators (53.2%) were found in de middle third of the PTR. The deep femoral artery (DFA) was the main origin of perforators (61.7%), followed by the superficial femoral artery (SFA) (27.7%) and the popliteal artery (PA) (10.6%). The DFA perforators were the longest with a mean length of 13.7 ± 4,69 cm, the SFA perforators were 9.79 ± 3.76 cm and the PA perforators were 8.6 ± 3.37 cm. The PTR offers a sufficient number of suitable perforators to serve as an adequate donorsite for pedicled and free flaps. © 2013 Wiley Periodicals, Inc. Microsurgery 33:376–382, 2013.
A Compact Circularly‐Polarized Antenna with Enhanced Bandwidth for Wban Applications
Authors: Kim Suhwan , Kwon Kyeol , Choi Jaehoon
Published: May 2013

In this study, a compact circularly‐polarized (CP) enhanced bandwidth instrument, scientific, and measurement (ISM) band (2.4–2.485 GHz) antenna with enhanced bandwidth is proposed for wireless body area network applications. To miniaturize the size and widen the CP bandwidth, two y‐shaped strips connected to ground and a partially meandered strip feed line were used. The manufactured antenna has a 10 dB return loss bandwidth of 46% (2170–3290 MHz) and a 3 dB axial‐ratio bandwidth of 29% (2110–2820 MHz). The maximum gain of the antenna is 4.87 dBic. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1738–1741, 2013
Dielectric Properties of Glucose Solutions in the 0.5–67 GHz Range
Authors: Smulders Peter F. M. , Buysse Martin G. , Huang Mingda D.
Published: May 2013

The dielectric properties of glucose solved in pure water as well as in a physiological solution have been measured. The results are considered in the context of noninvasive diabetes control. At least 0.002 percent measurement accuracy is required to achieve the same accuracy as obtained with traditional finger pricking. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1916–1917, 2013
A Low Power and High Conversion Gain 60‐Ghz Cmos Up‐Conversion Mixer Using Current Injection and Dual Negative Resistance Compensation Techniques
Authors: Tsai Tzung‐Min , Lin Yo‐Sheng , Wen Wei‐Chen
Published: May 2013

A 60‐GHz double‐balanced mixer for direct up‐conversion using standard 90‐nm CMOS technology is reported. The up‐conversion mixer comprises an enhanced double‐balanced Gilbert cell with current injection for power consumption reduction, and negative resistance compensation for conversion gain (CG) enhancement, a Marchand balun for converting the single local oscillator (LO) input signal to differential signal, and another Marchand balun for converting the differential radio frequency (RF) output signal to single signal. The mixer consumes 8.83 mW and achieves intermediate frequency (IF)‐port input return loss of −12.3 dB at 0.1 GHz, LO‐port input return loss of −15.4 to −26.7 dB, and RF‐port input return loss of −12.1 to −28.5 dB for frequencies 57–64 GHz. At IF of 0.1 GHz, the mixer achieves CG of 2 dB and LO‐RF isolation of 48.8 dB at RF of 60 GHz. The corresponding 3‐dB bandwidth of RF is 4.4 GHz (57.7–62.1 GHz). To the authors' knowledge, the LO‐RF isolation and power consumption are the best results ever reported for a 60‐GHz CMOS/BiCMOS up‐conversion mixer. In addition, the measured output 1‐dB compression point and input third‐order intermodulation point are −10.1 and −2.15 dBm, respectively, at RF of 60 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1830–1836, 2013
A Compact Coupling Controllable Elliptical Filter Based on Multilayer LTCC
Authors: Meng, Fanyi , Ma Kaixue , Yeo Kiat Seng , Boon Chirn Chye , Xu, Shanshan , Lim Wei Meng , Do Manh Anh
Published: May 2013

This paper presents a compact elliptical filter based on modified λ/4 resonators with separated electric and magnetic coupling paths. For the proposed second‐order filters, transmission zero points are generated at either lower or upper stopband by controlling the relative coupling strength in the two paths of inter‐stage resonators. Based on the topology and multilayer LTCC technology, a fourth‐order bandpass filters operating at 5.2 GHz with a fractional bandwidth of 10% in 1.7 mm × 3 mm (0.0785λg × 0.1385λg) is designed and verified experimentally. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1789–1792, 2013
A Novel Design of Microstrip Antenna for Microwave Imaging Application
Authors: Ojaroudi Nasser , Ojaroudi Mohammad
Published: May 2013

In this article, a novel ultrawideband printed monopole antenna for microwave imaging systems is presented. The proposed antenna provides a wide usable fractional bandwidth of more than 160% (2.12–17.87 GHz). The antenna has an ordinary square radiating patch, therefore displays a good omnidirectional radiation pattern even at higher frequencies and also its radiation efficiency is greater than 82% across the entire radiating band. The designed antenna has a small size of 12 × 18 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1755–1758, 2013
Low Cost Refractive Index Sensor Based on Optical Lensed Fiber
Authors: Lin Yu‐Cheng , Liu Chien‐Fu
Published: May 2013

A refractive index (RI) sensor based on back reflection of an optical lensed fiber is demonstrated. The sensing device is fabricated by splicing a tiny gradient index fiber (GIF) on the tip of a single mode fiber. Symmetry mirror modeling and fiber coupling efficiency are utilized to estimate the dependence of reflection power on lens pitch. As for sensing test experiments, we measured the reflection power of RI sensor with different concentrations of glycerol solution from 0 to 100% in steps of 20% increasing. The results are consistent with theoretical curve. In terms of the experimental data, important characteristics including resolution and sensitivity are obtained. The RI sensor exhibits high sensitivity −884.62 dB for high RI sensed solution. As the high index GIF spliced on tip of the sensor, it helps to extend the sensing range from 1.45 to 1.472. Due to properties of easy fabrication and low material cost, we believe the RI sensor has potential in mass production and wide application. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1744–1746, 2013
Tunable Multiwavelength Brillouin‐Erbium Fiber Laser Based on Fiber Amplified Loop
Authors: Shaogang, Dai , Xuefang, Zhou , Tianshu Wang
Published: May 2013

A novel linear multiwavelength Brillouin‐erbium fiber laser based on a nonlinear fiber amplified loop is demonstrated. The nonlinear fiber amplified loop induces wavelength‐dependent cavity loss and it provides flexibility on controlling the amount of light reflected and transmitted into and out of the laser's cavity. At the Brillouin pump (BP) power of 25 mW and the 980 nm pump power of 200 mW, 21 output channels with 0.08 nm channel spacing are achieved. We realize the tunable output of multiwavelength through adjusting the polarization controller and the BP wavelength. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1741–1743, 2013
Membrane Antenna Arrays Fed by Substrate Integrated Waveguide for V‐Band Communication
Authors: Vettikalladi, Hamsakutty , Lafond Olivier , Himdi Mohamed
Published: May 2013

A low‐cost membrane antenna arrays based on FR4 and thin flexible Pyralux substrate for high speed 60 GHz communication systems are proposed. The thin substrate used for making the antenna helps for the easy integration with millimeter wave components and circuits. The low‐cost thin Pyralux substrate with a thickness of 75μm, relative permittivity of εr = 2.4 and tan δ = 0.002 is used. In this article, we are proposing a slot coupled single patch with substrate integrated waveguide (SIW) technology, 1 × 4 antenna array with (a) a combination of SIW and microstrip feed network and (b) SIW complete feed network, and finally a 1 × 16 array of patch antennas fed by complete SIW feed technology. Measurements of the prototypes show good results in terms of impedance bandwidth and antenna gain around 60 GHz. The measured results are in agreement with the numerical simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1746–1752, 2013
90° branch‐line Coupler with Reconfigurable Output Power Ratios
Authors: Batgerel Ariunzaya , Eom Soon‐Young
Published: May 2013

This letter introduces a new 90° branch‐line coupler with reconfigurable output power ratios (90° BC‐ROPR). Unlike a conventional branch‐line coupler structure, each arm of the proposed 90° BC‐ROPR is defined by an asymmetrically coupled‐line, and its characteristic impedance depends on the configuration of the coupled‐line. The main problem that challenged this structure was unwanted loop resonance from the inner transmission lines which form a loop in a disconnected configuration. The proposed structure was designed to obtain 1:1 and 4:1 output power ratios at 3 GHz. Both the simulation and measurement results confirm that the proposed branch‐line coupler successfully dealt with the loop resonance and achieved excellent performance. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1878–1881, 2013
Simultaneous Measurement of Temperature and Force Using a Fiber Bragg Grating on an Open Loop
Authors: Huang Yonglin , Wen Shuaichuan
Published: May 2013

Simultaneous measurement of temperature and force based on an open loop using a fiber Bragg grating (FBG) is proposed and demonstrated. A FBG is attached on a special constructed open loop that is composed of two kinds of materials. Using the difference of the Young's modulus and the thermal expansion coefficients for two parts of the FBG, the FBG has two reflection peaks at different wavelength when the temperature and force are applied on the sensor. Two Bragg reflection wavelengths are shift by temperature and force change. Linear response to temperature and force are achieved in the measurable temperature range from 22 to 82°C and in the measurable force range from 0 to 10 N. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1800–1802, 2013
Novel Fiber Optic Gas Sensor Based on Photonic Crystal Slow‐Light Waveguide
Authors: Wang Qi , Han Bo , Wu Di , Zhao Yong
Published: May 2013

Photonic crystal was first proposed as a new kind of material in1980s as it can control the movement of the photon which moves in it. In this article, we proposed and demonstrated the theory and method that photonic crystal waveguide (PCW) producing slow light, and slow light enhancing the light–matter interaction and gas molar absorption coefficient. On the basis of this, we proposed and designed a new type of optical fiber gas sensor by utilizing PCW and slow light produced by the PCW. Finally, through theory analysis, we conclude that the sensitivity of this new fiber optic sensor increases 12.56 times and the volume of the system unit is also significantly reduced. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1796–1800, 2013
Influence of Handset Components into the Behavior of a Handset Antenna in a Slotted Ground Plane
Authors: Bujalance Adrian , Picher Cristina , Anguera Jaume , Andújar Aurora , Puente Carles
Published: May 2013

The influence of handset components needs to be analyzed in order to optimize the integration of the antenna into a handset device. Therefore, a multiband handset antenna combining a planar spiral‐shaped monopole and a slotted ground plane is used to study the influence of different components over the antenna performance. The antenna features a suitable behavior to operate in several mobile communication standards such as GSM850, GSM900, GSM1800, GSM1900, UMTS2100, LTE2100, LTE2300, WiFi, and Bluetooth. The effect of a display, a speaker, and a battery has been investigated and recommendation rules are proposed in order to facilitate the integration of those components over the slotted ground plane without degrading the multiband performance. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1770–1779, 2013
Dual‐Band Monopole Antenna with Compact Radiator for 2.4/3.5 GHz WiMAX Applications
Authors: Sun Xiaolei L. , Cheung S. W. , Yuk T. I.
Published: May 2013

The article presents the design of a compact dual‐band monopole antenna with microstrip‐fed for use in wireless devices in the worldwide interoperability for microwave access (WiMAX) system. The radiator of the antenna has a compact size of only 14.5 × 8.7 mm2 and consists of a short stem and two branches generating two frequency bands at around 2.4 and 3.5 GHz for the WiMAX system. The two frequency bands can be easily and independently set using the parameters of the two radiating branches. The antenna performance in terms of reflection coefficient, radiation pattern, peak gain, and efficiency is studied using computer simulation. For verification of simulation results, the antenna is fabricated and measured using the antenna measurement system Satimo Starlab. The feeding cable used to connect the antenna to the measurement system causes substantial discrepancies between the simulated and measured results. To study the cable effects, the feeding cable is modeled and used in computer simulation for studies. With the use of the cable model, the simulated and measured results agree very well. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1765–1770, 2013
A 60‐GHz CMOS Down‐Conversion Mixer with Current‐Reused RF Single‐to‐Differential Converter and Integrated Marchand Balun
Authors: Lee Jen‐How , Lin Yo‐Sheng
Published: May 2013

A 60‐GHz double‐balanced mixer for direct down‐conversion using standard 90‐nm CMOS technology is reported. The down‐conversion mixer comprises a double‐balanced Gilbert cell with a current‐reused RF single‐to‐differential converter for conversion gain (CG) enhancement, a Marchand balun for converting the single LO input signal to differential signal, and a baseband amplifier. The mixer consumes 17 mW and achieves low noise figure of 12.8 dB at 60 GHz. In addition, the mixer achieves excellent LO‐RF isolation of 64.7 dB, LO‐IF isolation of 51.5 dB, and RF‐IF isolation of 59.5 dB at RF of 60 GHz and LO of 59.9 GHz. At IF of 0.1 GHz, the mixer achieves maximum CG of 15.46 dB at RF of 62 GHz, and CG of 14.7 dB at RF of 60 GHz, one of the best CG results ever reported for a 60‐GHz CMOS down‐conversion mixer. The corresponding 3‐dB bandwidth of RF is 5.4 GHz (58.7–64.1 GHz). These results demonstrate the proposed down‐conversion mixer architecture is very promising for 60‐GHz direct‐conversion transceiver applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1937–1946, 2013
A Wide Tuning Range CMOS Oscillator Mixer Using A Push–Push Technique for V‐Band Applications
Authors: Ke Po‐Yu , Huang Fan‐Hsiu , Kao Hsuan‐Lin , Chiu Hsien‐Chin
Published: May 2013

This work proposes a wide tuning oscillator mixer that operates from 56 to 64 GHz and is based on 90 nm CMOS technology. The circuit of a voltage control oscillator (VCO) comprises a mixer core and a coupled line marchand balun. The balanced mixer is symmetric, inherently broadband, and dependent on an LO balun that is combined with the parasitic capacitances from the mixer. The VCO is used in a 60 GHz push–pull circuit to generate the second harmonic, and a 30 GHz dielectric resonator is utilized to stabilize the fundamental oscillation frequency. The LC‐tank oscillator also functions as a single‐balanced LO load for the mixer core. A theoretical expression for the conversion gain of the self‐oscillating mixer is given, taking into account the time‐varying nature of the LO load impedance. Measurements show that the mixer has a conversion gain of 3.4 dB. Its output P1 dB is −12.4 dBm. The chip consumes 17.9 mW of dc power and it occupies an area of 0.64 mm2 without pads. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1934–1937, 2013
Dual‐Band Wlan Antenna Design by Controlling Higher Order Mode Characteristic
Authors: Yu Jaekyu , Zhang Rui , Liu Yang , Kim Hyung‐Hoon , Kim Hyeongdong
Published: May 2013

This article presents a new method for designing a dual‐band WLAN antenna using the higher order harmonic mode of a monopole antenna, the first‐order mode of which operates at the low‐frequency band of WLAN (2.4 GHz). After measuring the current distribution in the higher order antenna mode, we added a stub in a location where the electric field is strong. This added stub brought the resonant frequency into the higher WLAN frequency band. Further, the input impedance was controlled by controlling the width of the branch without affecting the low‐frequency band of the WLAN (the first‐order mode of the monopole antenna). This compact dual‐band antenna was designed to be the size of a universal serial bus dongle, and the −10 dB bandwidths are 700 MHz (2.3–3 GHz) at 2 GHz and 1 GHz (4.9–5.9 GHz) at 5 GHz, which cover the full WLAN dual bands. The proposed antenna achieves more than 50% efficiency in WLAN bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1897–1902, 2013
Power Divider with Arbitrary Power Ratio and Arbitrary Ripple Level Using Filter Synthesis Techniques
Authors: Zhang Qingfeng , Caloz Christophe
Published: May 2013

A novel type of power divider, featuring arbitrary power ratio and arbitrary ripple level, is proposed. This divider consists of a two‐port filtering structure connected to a circulator and is straightforwardly designed using microwave filter synthesis techniques. An example is provided, with low‐pass domain synthesis and experimental divider demonstration at the X‐band, after low‐pass to bandpass transformation. The experimental divider prototype is an iris coupled‐resonator waveguide structure, whose response is found in good agreement with theoretical predictions. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1819–1820, 2013
an 800‐MHz LC‐VCO with a Linear Control Characteristics in a 130‐nm CMOS Technology
Authors: Lee Hui Dong , Jung Jae Ho , Lee Kwang Chun
Published: May 2013

A semilinear LC‐voltage‐controlled oscillator (VCO) topology is proposed. To exploit a linear frequency tuning, the LC‐VCO adopts the variable capacitance block of the varactor devices and the PMOS transistors. This block has the capacitance characteristics which are approximately inversely proportional to the square of the VCO control voltage. The proposed LC‐VCO is implemented in a 130‐nm CMOS technology. The measurement results show a semilinear frequency range of 503–873 MHz and a phase noise of −128 dBc/Hz at 1 MHz offset frequency. Power consumption is about 2 mA from a 1.2 V supply. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1972–1975, 2013
Reconfigurable Hexa‐Band Planar Inverted‐F Antenna Using a PIN Diode for Mobile Handset
Authors: Lee Junhyuk H. , Sung Youngje
Published: May 2013

A compact, reconfigurable planar inverted‐F antenna (PIFA) for mobile phone applications is presented. Based on recent smart‐phone geometries, a PIN diode on an antenna radiator is used for frequency‐reconfigurable operation with a PIFA structure. The proposed novel hexa‐band built‐in mobile antenna, which is designed to cover LTE, GSM850, GSM900, DCS, PCS, and UMTS bands, is satisfactory in terms of its reflection coefficient, radiation patterns, and average gain (efficiency). A prototype is investigated, and good agreement between simulations and measurements is shown. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1926–1928, 2013
A Dual‐Band Narrow Band‐Pass Filter with Half‐Wavelength Open Stubs Using the CRLH Metamaterial
Authors: Yoon, Ki‐Cheol , Lee Hyun‐Wook , Lee Jong‐Chul , Kim Seong‐Cheol
Published: May 2013

A narrow‐bandwidth dual‐band (DB) band‐pass filter (BPF) with λg/2 open stubs constructed using composite right/left‐handed (CRLH) metamaterial transmission lines (TLs) is presented. A conventional narrow BPF with λg/2 open stubs is first designed using series λg/2 open stubs and λg/4 TLs. Then, a DB filter can then be easily implemented by replacing the microstrip lines with the CRLH‐TL unit cells. The DB BPF using the CRLH‐TL unit cell is experimentally demonstrated at dual‐operating frequencies of 5.8 and 10.02 GHz. The experimental results are in good agreement with the simulation results. The DB BPF shows 11 and 13% pass bandwidth at the center frequencies of 5.8 and 10.02 GHz, respectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1887–1890, 2013
A Dualband Coupled‐Fed Lte/Wwan Planar Antenna for Mobile Devices
Authors: Sim Chow‐Yen‐Desmond , Chien Yu‐Lun
Published: May 2013

A coupled‐fed antenna that combines the long term evolution operation with the wireless wide area network operation is proposed. The antenna is mainly composed of a T‐shaped radiator linked to the ground plane via a narrow meandered line. Good impedance matching throughout all bands of interest is achieved by embedding a C‐shaped coupling structure into the narrow meandered line, followed by protruding a small stub at the right bottom corner (vertical structure) of the T‐shaped radiator. Furthermore, by reconstructing the coupled‐fed structure as a halved‐tapered fed design, two wide operating bands that operate between 680 and 1380 MHz (68%), and 1550 and 2830 MHz (58.4%) are achieved. The process of designing the proposed antenna is explicitly shown, and parametric studies were carried out by simulation. Typical experimental measurements were also conducted and compared to the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1851–1856, 2013
Compact Wide‐Band Branch‐Line Coupler with Meander Line, Cross, and Two‐Step Stubs
Authors: Sa'ad B. M. , Rahim Sharul K.A. , Dewan Raimi
Published: May 2013

Despite being widely used, branch‐line couplers (BLC) still suffer from large size. This makes it difficult to incorporate BLC into miniature microwave devices. The work presented here is the design and implementation of a 3‐dB reduced‐size wide‐band 3‐branch‐line coupler (3‐BLC). By combining meander line, cross, and two‐step stubs techniques, size reduction and bandwidth improvement is successfully achieved on 3‐BLC design. The 3‐BLC length was reduced along the horizontal branches using two‐step reduction technique while the center vertical branch was reduced using cross stubs. A simple two‐turn meander line is utilized at the two ends vertical branches of the coupler to obtain balanced length with the middle vertical branch. Hence, its width was optimized to maximize the coupler bandwidth. The 3‐BLC was designed to operate at 2.45 GHz wireless local area network frequency band (IEEE 802.11 b/g) and fabricated on a 1.6 mm thick FR‐4 board. The simulated and measured results are in very good agreement and show a fractional bandwidth of 50% and a sized reduction of 61.64% at the center of the frequency band. The proposed coupler design provides BLC that occupies less space, simple to implement, and wide‐band BLC architecture with generic 3‐BLC wide‐band characteristics retained. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1810–1815, 2013
Novel Polarization Independent Metamaterial and its Application in Patch Antenna
Authors: Kumar Anand , Kumar V. Dinesh
Published: May 2013

We report a new structure of metamaterial, consisting of an array of double concentric rings and cross stripes of metal film separated by a dielectric layer. Using Finite Integration Technique, its properties are investigated; the metamaterial exhibits left handed behavior for both linear as well as circular polarization. Further the metamaterial is used as a cover to improve the directionality of a rectangular patch antenna using quadrature feed for producing a focused circularly polarized beam at frequency 11 GHz.© 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1963–1969, 2013
ERRATUM: A Novel Low‐Voltage Tunable Capacitor for Tunable RF Circuit Applications
Authors: Chul Lee, Young , Ju Lee Baek , Hyun Ko Kyung
Published: May 2013

Originally published Microwave Opt Technol Lett 55: 1152–1155, 2013. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1976, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27740 (Original article DOI 10.1002/mop.27500)
Simultaneous multislice excitation by parallel transmission
Authors: Poser Benedikt A. , Anderson Robert James , Guérin Bastien , Setsompop Kawin , Deng Weiran , Mareyam Azma , Serano Peter , Wald Lawrence L. , Stenger V. Andrew
Published: May 2013

Purpose

A technique is described for simultaneous multislice (SMS) excitation using radiofrequency (RF) parallel transmission (pTX).

Methods

Spatially distinct slices are simultaneously excited by applying different RF frequencies on groups of elements of a multichannel transmit array. The localized transmit sensitivities of the coil geometry are thereby exploited to reduce RF power. The method is capable of achieving SMS‐excitation using single‐slice RF pulses, or multiband pulses. SMS‐pTX is demonstrated using eight‐channel parallel RF transmission on a dual‐ring pTX coil at 3 T. The effect on B1+ homogeneity and specific absorption rate (SAR) is evaluated experimentally and by simulations. Slice‐GRAPPA reconstruction was used for separation of the collapsed slice signals.

Results

Phantom and in vivo brain data acquired with fast low‐angle shot (FLASH) and blipped‐controlled aliasing results in higher acceleration (CAIPIRINHA) echo‐planar imaging are presented at SMS excitation factors of two, four, and six. We also show that with our pTX coil design, slice placement, and binary division of transmitters, SMS‐pTX excitations can achieve the same mean flip angles excitations at ∼30% lower RF power than a conventional SMS approach with multiband RF pulses.

Conclusion

The proposed SMS‐pTX allows SMS excitations at reduced RF power by exploiting the local B1+ sensitivities of suitable multielement pTX arrays. Magn Reson Med 71:1416–1427, 2014. © 2013 Wiley Periodicals, Inc.
The perturbation bound for the Perron vector of a transition probability tensor
Authors: Li Wen , Cui Lu‐Bin , Ng Michael K.
Published: May 2013

In this paper, we study the perturbation bound for the Perron vector of an mth‐order n‐dimensional transition probability tensor with and . The Perron vector x associated to the largest Z‐eigenvalue 1 of , satisfies where the entries xi of x are non‐negative and . The main contribution of this paper is to show that when is perturbed to an another transition probability tensor by , the 1‐norm error between x and is bounded by m, , and the computable quantity related to the uniqueness condition for the Perron vector of . Based on our analysis, we can derive a new perturbation bound for the Perron vector of a transition probability matrix which refers to the case of m = 2. Numerical examples are presented to illustrate the theoretical results of our perturbation analysis. Copyright © 2013 John Wiley & Sons, Ltd.
Pilot study identifying myosin heavy chain 7, desmin, insulin‐like growth factor 7, and annexin A2 as circulating biomarkers of human heart failure
Authors: Chugh Shaan , Ouzounian Maral , Lu Zhen , Mohamed Shanas , Li Wenping , Bousette Nicolas , Liu Peter P. , Gramolini Anthony O.
Published: May 2013

In‐depth proteomic analyses offer a systematic way to investigate protein alterations in disease and, as such, can be a powerful tool for the identification of novel biomarkers. Here, we analyzed proteomic data from a transgenic mouse model with cardiac‐specific overexpression of activated calcineurin (CnA), which results in severe cardiac hypertrophy. We applied statistically filtering and false discovery rate correction methods to identify 52 proteins that were significantly different in the CnA hearts compared to controls. Subsequent informatic analysis consisted of comparison of these 52 CnA proteins to another proteomic dataset of heart failure, three available independent microarray datasets, and correlation of their expression with the human plasma and urine proteome. Following this filtering strategy, four proteins passed these selection criteria, including myosin heavy chain 7, insulin‐like growth factor‐binding protein 7, annexin A2, and desmin. We assessed expression levels of these proteins in mouse plasma by immunoblotting, and observed significantly different levels of expression between healthy and failing mice for all four proteins. We verified antibody cross‐reactivity by examining human cardiac explant tissue by immunoblotting. Finally, we assessed protein levels in plasma samples obtained from four unaffected and four heart failure patients and demonstrated that all four proteins increased between twofold and 150‐fold in heart failure. We conclude that MYH7, IGFBP7, ANXA2, and DESM are all excellent candidate plasma biomarkers of heart failure in mouse and human.
Proteomic approach toward molecular backgrounds of drug resistance of osteosarcoma cells in spheroid culture system
Authors: Arai Kazuya , Sakamoto Ruriko , Kubota Daisuke , Kondo Tadashi
Published: May 2013

Chemoresistance is one of the most critical prognostic factors in osteosarcoma, and elucidation of the molecular backgrounds of chemoresistance may lead to better clinical outcomes. Spheroid cells resemble in vivo cells and are considered an in vitro model for the drug discovery. We found that spheroid cells displayed more chemoresistance than conventional monolayer cells across 11 osteosarcoma cell lines. To investigate the molecular mechanisms underlying the resistance to chemotherapy, we examined the proteomic differences between the monolayer and spheroid cells by 2D‐DIGE. Of the 4762 protein species observed, we further investigated 435 species with annotated mass spectra in the public proteome database, Genome Medicine Database of Japan Proteomics. Among the 435 protein species, we found that 17 species exhibited expression level differences when the cells formed spheroids in more than five cell lines and four species out of these 17 were associated with spheroid‐formation associated resistance to doxorubicin. We confirmed the upregulation of cathepsin D in spheroid cells by western blotting. Cathepsin D has been implicated in chemoresistance of various malignancies but has not previously been implemented in osteosarcoma. Our study suggested that the spheroid system may be a useful tool to reveal the molecular backgrounds of chemoresistance in osteosarcoma.
Amino, ammonio and aminioethenes: a theoretical study of their structure and energetics
Authors: Miranda Margarida S. , Esteves da Silva Joaquim C. G. , Castillo Alvaro , Frank Aaron T. , Greer Alexander , Brown Jodian A. , Davis Brittny C. , Liebman Joel F.
Published: May 2013

We have performed high level ab initio quantum mechanical calculations for aminoethene and the three isomeric 1,1‐ (Z)‐ or (E)‐1,2‐diaminoethenes as well as their singly and doubly charged cations derived by loss of electrons and/or upon protonation. Gas phase molecular structures were computed at the MP2/6‐311 + G(3df,2p) level. Standard molar enthalpies of formation in the gas phase, at T = 298.15 K, were estimated using the G3 composite method and atomization, isodesmic and homodesmotic reactions. Other energetic parameters were also calculated at the G3 level: proton affinities, basicities and adiabatic ionization enthalpies.

Theoretical and experimental data are compared. The reported experimental data refer only to aminoethene wherein the standard molar enthalpy of formation has a considerable uncertainty, although the molecular structure is well established. There are no such data, neither structural nor thermochemical, for any of the three isomeric diaminoethenes. Isoelectronic comparisons are made. For example, the diprotonated diaminoethenes are isoelectronic to isobutene and (Z)‐ and (E)‐butene, while the doubly ionized diaminoethenes are likewise related to trimethylenemethane and 1,3‐butadiene. Copyright © 2013 John Wiley & Sons, Ltd.
Numerical Investigation of SiO2 Coating Deposition in Wafer Processing Reactors with SiCl4/O2/Ar Inductively Coupled Plasmas
Authors: Tinck Stefan , De Schepper Peter , Bogaerts Annemie
Published: May 2013

Simulations and experiments are performed to obtain a better insight in the plasma enhanced chemical vapor deposition process of SiO2 by SiCl4/O2/Ar plasmas for introducing a SiO2‐like coating in wafer processing reactors. Reaction sets describing the plasma and surface chemistry of the SiCl4/O2/Ar mixture are presented. Typical calculation results include the bulk plasma characteristics, i.e., electrical properties, species densities, and information on important production and loss processes, as well as the chemical composition of the deposited coating, and the thickness uniformity of the film on all reactor surfaces. The film deposition characteristics, and the trends for varying discharge conditions, are explained based on the plasma behavior, as calculated by the model.
Heat Flux Measurement from Bulk Magnesium/Teflon/Viton (MTV) Flare Composition Combustion
Authors: Williams Michael R. , Dunne Jennifer L.
Published: May 2013

Radiant heat output has been measured from an MTV flare composition for masses between 0.2 and 36 kg. Around 30 % of the heat of reaction is lost as radiation. The maximum temperature at the surface of the fireball is estimated to be around 1800 K. The effect of distance on the received radiated heat dose is complex but, with large buoyant fireballs, the attenuation might be as small as the inverse of distance.
Agglomeration Characteristics of Aluminum Particles in AP/AN Composite Propellants
Authors: Takahashi Kenichi , Oide Sho , Kuwahara Takuo
Published: May 2013

Most solid rockets are powered by ammonium perchlorate (AP) composite propellant including aluminum particles. As aluminized composite propellant burns, aluminum particles agglomerate as large as above 100 μm diameter on the burning surface, which in turn affects propellant combustion characteristics. The development of composite propellants has a long history. Many studies of aluminum particle combustion have been conducted. Optical observations indicate that aluminum particles form agglomerates on the burning surface of aluminized composite propellant. They ignite on leaving the burning surface. Because the temperature gradient in the reaction zone near a burning surface influences the burning rate of a composite propellant, details of aluminum particle agglomeration, agglomerate ignition, and their effects on the temperature gradient must be investigated. In our previous studies, we measured the aluminum particle agglomerate diameter by optical observation and collecting particles. We observed particles on the burning surface, the reaction zone, and the luminous flame zone of an ammonium perchlorate (AP)/ammonium nitrate (AN) composite propellant. We confirmed that agglomeration occurred in the reaction zone and that the agglomerate diameter decreased with increasing the burning rate. In this study, observing aluminum particles in the reaction zone near the burning surface, we investigated the relation between the agglomerates and the burning rate. A decreased burning rate and increased added amount of aluminum particles caused a larger agglomerate diameter. Defining the extent of the distributed aluminum particles before they agglomerate as an agglomerate range, we found that the agglomerate range was constant irrespective of the added amount of aluminum particles. Furthermore, the agglomerate diameter was ascertained from the density of the added amount of aluminum particles in the agglomerate range. We concluded from the heat balance around the burning surface that the product of the agglomerate range and the burning rate was nearly constant irrespective of the added amount of aluminum particles. Moreover, the reduced burning rate increased the agglomerate range.
On the Reliability of Sensitivity Test Methods for Submicrometer‐Sized RDX and HMX Particles
Authors: Radacsi Norbert , Bouma Richard H. B. , Krabbendam‐la Haye Ellen L. M. , ter Horst Joop H. , Stankiewicz Andrzej I. , van der Heijden Antoine E. D. M.
Published: May 2013

Submicrometer‐sized RDX and HMX crystals were produced by electrospray crystallization and submicrometer‐sized RDX crystals were produced by plasma‐assisted crystallization. Impact and friction sensitivity tests and ballistic impact chamber tests were performed to determine the product sensitivity. Rather than reflecting the quality of the particles, we found the sensitivity tests to be unreliable for submicrometer particles. The used impact test was not accurate enough, while in the friction and ballistic impact chamber tests the submicrometer‐sized crystals were distributed among the grooves of the porcelain plate or among the grains of the sandpaper used in these tests. These observations stress the need for revisiting the current standards used for determining the hazardous properties like friction and impact sensitivity of energetic materials in the case, where the sample consists of submicrometer‐sized crystals. Recommendations were suggested to develop new test methods that only use the interactions between the particles and therefore allow the application of sensitivity tests for submicrometer/nano‐sized energetic materials.
Transition from Impact‐induced Thermal Runaway to Prompt Mechanochemical Explosion in Nanoscaled Ni/Al Reactive Systems
Authors: Reeves Robert V. , Mukasyan Alexander S. , Son Steven F.
Published: May 2013

The effect of microstructure on ignition sensitivity and reaction behavior is investigated for nanoscaled Ni/Al gasless reactive systems. Nanometric homogeneity of the reactive media was achieved through (a) conventional mixing of nanometric powders; (b) short‐term high‐energy ball milling (HEBM) of micrometer‐sized powders. Sensitivity to thermal inputs is investigated by differential thermal analysis and mechanical sensitivity is studied by high‐rate shear impacts. The composite Ni/Al particles prepared by HEBM were extremely thermally sensitive, with reaction initiating at 220 °C, compared to 559 °C for nanometric powder samples and 640 °C for un‐milled, micrometer‐sized Ni+Al powder mixture. In contrast, nanometric powder mixtures were more susceptible to ignition through mechanical means, exhibiting a high‐speed reaction mode that is not observed in HEBM samples. The high‐speed mode preferentially appears in high‐shear regions and is interpreted as a mechanically‐induced thermal explosion. Its progression is tied to the passage of a stress wave in the heterogeneous media that heats and mixes the materials, rather than being propagated due to chemical energy release. The microstructures unique to each material are considered responsible for their individually ignition sensitivities. Specifically, the finely interspersed porosity in nanometric powder mixtures allows direct heating of the reactive interface between Ni and Al particles during compression through pore collapse and plastic deformation, which leads to exceptionally high mechanical sensitivity. The HEBM materials have high specific reactant interface area in the bulk of each composite particle that enhances thermal sensitivity, but the relatively low specific interface area between particles is unfavorable to mechanical ignition.
Effect of spray angle and spray volume on deposition of a medium droplet spray with air support in ivy pot plants
Authors: Foqué Dieter , Pieters Jan G. , Nuyttens David
Published: May 2013

BACKGROUND

Spray boom systems, an alternative to the predominantly‐used spray guns, have the potential to considerably improve crop protection management in glasshouses. Based on earlier experiments, the further optimization of the deposits of a medium spray quality extended range flat fan nozzle type using easy adjustable spray boom settings was examined. Using mineral chelate tracers and water sensitive papers, the spray results were monitored at three plant levels, on the upper side and the underside of the leaves, and on some off‐target collectors. In addition, the deposition datasets of all tree experiments were compared.

RESULTS

The data showed that the most efficient spray distribution with the medium spray quality flat fan nozzles was found with a 30° forward angled spray combined with air support and an application rate of 1000 L ha–1. This technique resulted in a more uniform deposition in the dense canopy and increased spray deposition on the lower side of the leaves compared with the a standard spray boom application. Applying 1000 L ha–1 in two subsequent runs instead of one did not seem to show any added value.

CONCLUSION

Spray deposition can be improved hugely simply by changing some spray boom settings like nozzle type, angling the spray, using air support and adjusting the spray volume to the crop. © 2013 Society of Chemical Industry