bluuebunny/crossref_metadata_2025 huggingface dataset:
Benzene polycarboxylic acids—A ubiquitous class of compounds in soils
Authors: Haumaier Ludwig
Published: July 2010

Black carbon (BC) occurs ubiquitously in the environment. Its oxidation in the laboratory yields a suite of benzene polycarboxylic acids (BPCAs), suggesting similar oxidation products in soils. Since only for a few soils the occurrence of BPCAs in the free form has been documented, screening for them in a broad range of contrasting soils was conducted. They were extracted from soil samples with 0.5 M NaOH and quantified using gas chromatography–mass spectrometry. As expected, BPCAs turned out to be as ubiquitous as BC. They were detected not only in every soil sample investigated so far, but also in samples from drill cores up to a depth of 10 m and in recently deposited calcareous tufa. The concentrations covered a range similar to that of some phenolic acids. The range exceeded those reported for low‐molecular‐weight aliphatic acids or simple sugars in soils. The distribution of BPCAs in soil profiles indicated a considerable potential of translocation within, and export from, soil, in particular of benzene hexacarboxylic (mellitic) acid. Mellitic acid may therefore be present in almost any geochemical sample affected by seepage water from soils. Its high water solubility and strong metal‐complexing ability suggest it may be involved in metal‐transport processes, at least on geological timescales.
New data on speleothem deposition and palaeoclimate in Britain over the last forty thousand years
Authors: Atkinson T. C. , Lawson T. J. , Smart P. L. , Harmon R. S. , Hess J. W.
Published: July 2010

230Th/234U dates are presented for 26 speleothems from three areas in Britain: Assynt, N.W. Scotland; N.W. Yorkshire; Mendip Hills, Somerset. These dates suggest that speleothem growth was widespread but rare in the period from 40 to 26 Ka, absent from 26 to 15 Ka, and abundant from 15 Ka to the present. The absence of speleothems between 26 and 15 Ka is attributed to glaciation in Yorkshire and Assynt and, tentatively, to continuous permafrost development in the Mendip Hills. The occurrence of speleothems before 26 Ka places restrictions on the extent of any ice sheet which may have been present in Scotland, and indicates that N.W. Scotland was not subjected to continuous permafrost at that time.
Adsorption of 2‐amino‐5‐cyanopyridine on a gold surface as probed by surface‐enhanced Raman spectroscopy
Authors: Xu Min‐Min , Yuan Ya‐Xian , Yao Jian‐Lin , Han San‐Yang , Wang Mei , Gu Ren‐Ao
Published: July 2010

The adsorption of 2‐amino‐5‐cyanopyridine (2‐ACP) was investigated in solution at different pH values by in situ surface‐enhanced Raman scattering (SERS) spectroscopy combined with the electrochemical method. The assignments of the main bands were first performed on the basis of the spectral features of similar compounds and with the help of density functional theory calculations. The results revealed that the adsorption and the interfacial structure of 2‐ACP on the Au electrode depended on the applied potential and the pH values of the solution. In the natural solution, 2‐ACP was adsorbed on the surface with a vertical orientation by the CN group from − 0.4 to − 1.0 V, whereas in the − 0.4 to 0.8 V range, the N atom of the pyridine ring was bound to the surface. A transition region for the reorientation of the two adsorption modes was observed from − 0.8 to − 0.4 V. A flat configuration was preferred at an extremely negative potential. A similar surface adsorption behavior was observed in the alkali environment, while the Stark effect slope decreased because of the adsorption of OH−. Due to the protonation of N atom in the acidic solution, the potential region for the coexistence of two configurations ranged from − 0.4 to 0.2 V. Additionally, a similar adsorption configuration was proposed on the Au colloids at various pH values. The results revealed that the adsorption behavior became more complex on colloidal surfaces than that on a rigid electrode surface. Copyright © 2010 John Wiley & Sons, Ltd.
Dropping macadamia nuts‐in‐shell reduces kernel roasting quality
Authors: Walton David A , Wallace Helen M
Published: July 2010

BACKGROUND: Macadamia nuts (‘nuts‐in‐shell’) are subjected to many impacts from dropping during postharvest handling, resulting in damage to the raw kernel. The effect of dropping on roasted kernel quality is unknown. Macadamia nuts‐in‐shell were dropped in various combinations of moisture content, number of drops and receiving surface in three experiments. After dropping, samples from each treatment and undropped controls were dry oven‐roasted for 20 min at 130 °C, and kernels were assessed for colour, mottled colour and surface damage.

RESULTS: Dropping nuts‐in‐shell onto a bed of nuts‐in‐shell at 3% moisture content or 20% moisture content increased the percentage of dark roasted kernels. Kernels from nuts dropped first at 20%, then 10% moisture content, onto a metal plate had increased mottled colour. Dropping nuts‐in‐shell at 3% moisture content onto nuts‐in‐shell significantly increased surface damage. Similarly, surface damage increased for kernels dropped onto a metal plate at 20%, then at 10% moisture content.

CONCLUSION: Postharvest dropping of macadamia nuts‐in‐shell causes concealed cellular damage to kernels, the effects not evident until roasting. This damage provides the reagents needed for non‐enzymatic browning reactions. Improvements in handling, such as reducing the number of drops and improving handling equipment, will reduce cellular damage and after‐roast darkening. Copyright © 2010 Society of Chemical Industry
Hypoxia inducible factor‐1α gene polymorphism G1790A and its interaction with tobacco and alcohol consumptions increase susceptibility to hepatocellular carcinoma
Authors: Hsiao Pei‐Ching , Chen Mu‐Kuan , Su Shih‐Chi , Ueng Kwo‐Chang , Chen Yi‐Chen , Hsieh Yi‐Hsien , Liu Yu‐Fan , Tsai Hsiu‐Ting , Yang Shun‐Fa
Published: July 2010

Background and Objectives

The aim of this study was to examine the potential associations of two hypoxia inducible factor‐1α (HIF‐1α) gene polymorphisms, C1772T and G1790A, with the susceptibility and clinicopathological status of hepatocellular carcinoma.

Methods

A total of 449 subjects, including 347 healthy controls and 102 patients with hepatocellular carcinoma, were recruited in this study and subjected to polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) analyses to estimate the impact of these two polymorphic variants on hepatocellular carcinoma.

Results

G1790A heterozygotes showed a higher risk for hepatocellular carcinoma, compared with GG genotypes after adjusting for other confounders (AOR = 3.97; 95%CI = 1.70–9.22), indicating a significant association between hepatocellular carcinoma susceptibility and G1790A polymorphism. Moreover, results also revealed the presence of synergistic effect between gene polymorphism of HIF‐1α G1790A and environmental risk factors, such as tobacco and alcohol consumptions while there was no significant association between HIF‐1α gene polymorphism and clinicopathological parameters of hepatocellular carcinoma.

Conclusions

Genetic polymorphism at G1790A of HIF‐1α is an important factor for determining the susceptibility to hepatocellular carcinoma. The interaction effects of G1790A heterozygotes to tobacco and to alcohol consumption significantly increase the risk to develop hepatocellular carcinoma. J. Surg. Oncol. 2010;102:163–169. © 2010 Wiley‐Liss, Inc.
Molecular Weight Distribution Evaluation of Polysaccharides and Glycoconjugates Using Analytical Ultracentrifugation
Authors: Harding Stephen E. , Abdelhameed Ali Saber , Morris Gordon A.
Published: July 2010

We review here the advances that have been made in methodology using the analytical ultracentrifuge for characterising polydisperse polymer systems with a quasi‐continuous distribution of molecular weight. These advances include improved ways of defining the weight and z‐average molecular weights of a distribution from sedimentation equilibrium experiments and hence the ratio $M_{{\rm z}} /M_{{\rm w}} $, off‐line calibration of size exclusion chromatography by sedimentation equilibrium and conversion of a sedimentation coefficient distribution into a molecular weight distribution. Although these methods are applicable to other polymeric systems, we focus on polysaccharides, mucins and other glycoconjugates, systems which particularly benefit from the availability of recently available long optical path length cells for the minimisation of complications through thermodynamic non‐ideality.

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Drought classification in Northern Serbia based on SPI and statistical pattern recognition
Authors: Stricevic Ruzica , Djurovic Nevenka , Djurovic Zeljko
Published: July 2010

This paper proposes a procedure for decision‐making regarding the extent to which a certain geographical region is affected by drought. Professional circles generally recognize the Standardized Precipitation Index (SPI) as a good indicator of a drought event. However, as a result of varying precipitation levels due to various local geographical, climatic, vegetational and other factors, this indicator is determined based on precipitation measurements and different meteorological centres within the same administrative region often generate different SPI values, even when the geographical distance between them is small. During a dry period, various local authorities, ministries of agriculture or governments have to make important decisions about, for example, declaring disasters, subsidizing farmers for certain crops, or providing financial aid to agricultural producers, based on voluminous and diverse data about local precipitation, the yield of various crops, or the condition of the soil. This paper proposes an automated methodology for such decision‐making, which can be used as a support tool by decision‐makers. The methodology is based on the SPI and statistical pattern recognition methods (dimension reduction and classifier design based on the desired output). The entire procedure is illustrated using Vojvodina, a region in Serbia in the southern portion of the Pannonian Plain, as a case study. The proposed algorithm is not subject to any constraints with regard to geographical locations of regions, their surface areas, or inter‐relationships. Copyright © 2010 Royal Meteorological Society
Temperature‐independent fiber bragg grating tilt sensor
Authors: Ni Kai , Dong Xinyong , Jin Yongxing , Xu Haisong
Published: July 2010

A novel fiber Bragg grating (FBG) tilt sensor is proposed to detect the magnitude and the direction of a two‐dimensional inclination by using four FBGs. High angle sensitivity and measurement resolution have been achieved, and the temperature effect has been eliminated completely without additional temperature compensation schemes. Experimental results verified the feasibility of the proposed idea. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2250–2252, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25425
Temperature‐independent vibration sensor with a fiber Bragg grating
Authors: Zhou Wenjun , Dong Xinyong , Shen Changyu , Zhao Chun‐Liu , Chan Chi Chiu , Shum Ping
Published: July 2010

A novel temperature‐independent vibration sensor based on a fiber Bragg grating (FBG) is demonstrated.The FBG was glued in a slanted direction onto the lateral side of a right‐angled triangle cantilever beam. Vertical vibration applied to the cantilever beam leads to a periodical variation of bending curvature along the beam length. As a result of beam bending, the FBG is chirped and its reflection bandwidth and optical power change with the deflection of the beam. Experimental results were compared with the data of vibration measurement of a conventional resistance strain gauge. Good agreement has been achieved. The sensor is temperature independent, owning to the temperature‐independence nature of the reflection bandwidth and optical power of the FBG. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2282–2285, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25429
Comparison between analytical and neural approaches for multibias small signal modeling of microwave‐scaled FETs
Authors: Marinković Zlatica , Crupi Giovanni , Caddemi Alina , Marković Vera
Published: July 2010

Small signal models of microwave field‐effect transistors (FETs) can be obtained by using different modeling techniques. This article considers two techniques: an analytical approach based on equivalent circuit representation and an optimization approach based on artificial neural networks. Both of the approaches are applied to extract multibias models of scaled microwave FETs. A comprehensive comparison of both techniques considering different modeling aspects is given. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2238–2244, 2010; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.25432
An internal multiband antenna with zeroth‐order resonator for usb dongle applications
Authors: Yu Yeonsik , Kim Giho , Seong Wonmo , Choi Jaehoon
Published: July 2010

A novel multiband inverted‐L (IL) antenna, intended for use in a universal serial bus (USB) dongle, is proposed. The internal antenna that we designed consists of an L‐shaped zeroth‐order resonator (ZOR) and a folded first‐order IL element, and has a compact volume of 30 ×15 ×7 mm. The proposed antenna provides the wide bandwidth necessary for covering long‐term evolution (LTE), digital cellular network (DCN), and personal communication system (PCS)‐1900 frequency bands. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2212–2214, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25433
Experiments on wave propagation at 6.0 GHz in a left‐handed waveguide
Authors: Barroso Joaquim J. , Castro Pedro J. , Leite Neto Joaquim P.
Published: July 2010

Microwave propagation in a metallic waveguide loaded with an array of split‐ring resonators is examined both analytically and experimentally. The synthesized combined medium exhibits a frequency band around 6.0 GHz with simultaneously negative values of permittivity and permeability, which allow transmission in an otherwise forbidden band for the hollow waveguide. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2175–2178, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25435
Compact ultra‐wideband bandpass filter using defected ground structures
Authors: Lee J. K. , Kim Y.‐S.
Published: July 2010

In this letter, a compact ultra‐wideband (UWB) bandpass filter (BPF) is presented with improved upper stopband performance using six defected ground structures (DGS).The proposed BPF is composed of seven DGSs which are positioned under the input and output microstrip line and coupled double step impedance resonator (CDSIR). By using CDSIR and open loop defected ground structure (OLDGS), we can achieve UWB BPF characteristics, and by using the conventional DGSs under input and output microstrip line, we can improve upper stopband performance. Simulated and measured results are found in good agreement with each other, showing a wide passband from 3.4 to 10.9 GHz, minimum insertion loss of 0.61 dB at 7.02 GHz and the group delay variation is less than 0.4 ns in the operating band while wide upper stopband with more than 30 dB attenuation up to 20 GHz. In addition, the proposed UWB BPF has a compact size. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2173–2175, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25436
All‐optical processing toward next generation wavelength agnostic passive optical networks
Authors: Teixeira A. , Costa L. , Wada N. , Chanclou P. , Forin D.M. , Prat J. , Tosi Beleffi G. M.
Published: July 2010

A simple, easy to integrate, low‐power consumption optical processing system able to break new ground on passive optical plant deployment realizing the implementation of pioneer multiple telecom operator scenarios is presented and experimentally investigated. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2378–2380, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25438
Broadband built‐in antenna with new enclosed 3D coupling feed structure
Authors: Kim Byoung‐Nam , Park Seong‐Ook , Oh Jung‐Keun
Published: July 2010

Wideband built‐in antenna with an enclosed 3D coupling feed structure for wireless terminals is presented.With the proposed design scheme, a nine‐band built‐in antenna that covers GSM850/GSM900/GPS/DCS1800/PCS1900/WCDMA/WiBro2350/Bluetooth/WiMax 2500 is experimentally tested. This novel nine‐band built‐in handset antenna is developed within the limits of a 40 × 17.5 × 6 mm3 volume, achieving good agreement between measurement and simulation. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2306–2309, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25441
Low power dual transformer injection locked frequency divider using 0.5 μm GaAs E/D‐mode PHEMTs process
Authors: Ke Po‐Yu , Chiu Hsien‐Chin , Fu Jeffrey S.
Published: July 2010

This letter proposes a new divide‐by‐2 injection locked frequency divider (ILFD) fabricated by 0.5 μm GaAs ED‐Mode PHEMTs process and describes the operation principle of the dual‐transformer ILFD. The first transformer is applied to replace two inductors of the cross‐couple LC‐tank oscillator circuit. The injection signal of the ILFD transmits into a transistor through a second transformer, which consisted of a bandpass filter achieving a high injection signal power and wide locking range. The measurement results show that the divider's free‐running frequency were from 6.47 to 9.54 GHz (32.2%) with 3 V supply voltage. With an incident power of 0 dBm, the locking range is 3.07 GHz from the incident frequency 16.41 to 19.45 GHz (15.6%). The measured phase noise of free running VCO is −92.2 dBc/Hz at 1 MHz offset frequency at 9.45 GHz and this value of the locked ILFD is −128.4 dBc/Hz, which is 36.2 dB lower than the free running VCO. The core power consumption was 42 mW. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2302–2306, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25442
Augmented equivalence principle algorithm at low frequencies
Authors: Sun L. E. , Chew W. C. , Jin J.M.
Published: July 2010

The present equivalence principle algorithm (EPA) is augmented by introducing charge densities as extra unknowns. This helps to separate the vector potential term and scalar potential term and avoid the imbalance at low frequencies. Current continuity constraint is enforced in both the scattering operator and translation operator. These further form a new augmented EPA equation system. With this technique, the low‐frequency breakdown of EPA is removed. Besides, it serves not only as a stable low‐frequency method but also as a substitute over the whole frequency band. The new scheme is verified by numerical examples. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2274–2279, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25443
Enhancement of ultra‐wideband microstrip monopole antenna by using unequal arms V‐shaped slot printed on metamaterial surface
Authors: Elsheak Dalia N. , Iskander Magdy F. , Elsade Hala A. , Abdallah Esmat A. , Elhenawy Hadia
Published: July 2010

A novel ultra‐wideband (UWB) printed monopole microstrip patch antenna is presented. The UWB is provided by using unequal V‐shaped slot arms to provide staggered resonance frequencies from different couplings. Second, using modified ground plane to enhance the bandwidth. An impedance bandwidth from 2 to 30 GHz is obtained using HFSS® with discontinuities in this bandwidth. For further enhancement in the bandwidth, antenna gain as well as removing the harmonic frequencies, the embedded electromagnetic band‐gap (EBG) structure is used. The impedance bandwidth reaches 2000%, covering the frequency range 0.5–40 GHz with bandwidth ratio of 80:1. Three different techniques of metamaterial are used, namely using embedded square shapes as artificial magnetic conductor, using embedded uniplanar square EBG structure without via, and, finally, using embedded metallo‐electromagnetic band‐gap structure with via. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2203–2209, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25447
Measurement of Stokes parameters of terahertz radiation in terahertz time‐domain spectroscopy
Authors: Dong Hui , Gong Yandong , Olivo Malini
Published: July 2010

We propose a technique for the measurement of Stokes parameters of terahertz radiation in terahertz time‐domain spectroscopy (THz‐TDS). In this technique, a rotatable wire‐grid THz polarizer is placed in front of a two‐contact photoconductive THz detector. Stokes parameters can be measured by making two temporal scans corresponding to two angles of the polarizer. We theoretically demonstrate that the two angles can be −45° and 45° for achieving the statistically best measurement accuracy in a single test. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2319–2324, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25450
Efficient and high‐gain aperture coupled superstrate antenna arrays for 60 GHz indoor communication systems
Authors: Vettikalladi Hamsakutty , Coq Laurent Le , Lafond Olivier , Himdi Mohamed
Published: July 2010

Efficient and high‐gain aperture coupled patch antenna arrays with superstrate at 60 GHz are studied and presented. It is noted that adding a superstrate with a specific size will induce a significant effect on antenna gain and radiation patterns. This capability is applied on the design of 2 × 2 and 4 × 4 arrays for high‐gain application. The maximum measured gain of a 2 × 2 superstrate antenna array is 16 dBi with an efficiency of 63%, which is 4 dB higher than that of a classical 2 × 2 array at 60 GHz. The 2:1 measured voltage standing wave ratio (VSWR) bandwidth is 6.8%. Also the maximum gain measured for a 4 × 4 superstrate antenna array is found to be 19.7 dBi with an estimated efficiency of 51%. The radiation patterns are found to be broadside all over the frequency band with very low back radiation. Hence aperture coupled superstrate antenna array is a good candidate for high‐efficient high‐gain application at 60 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2352–2356, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25455
An ultra‐wideband planar inverted‐F antenna
Authors: Chattha Hassan T. , Huang Yi , Lu Yang , Zhu Xu
Published: July 2010

The planar inverted‐F antenna (PIFA) is widely used in mobile and portable radio devices due to its excellent performance. However, it is not yet employed as an ultra‐wideband antenna due to its perceived narrow band characteristics. This article introduces a new PIFA for frequencies from about 3 GHz to 10 GHz, with a fractional bandwidth of about 100%, which is ideal for emerging ultra‐wideband (UWB) wireless applications. Simulated and measured results are provided to verify the conclusion. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2285–2288, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25458
An efficient CMOS power‐combining technique with differential and single‐ended power amplifier
Authors: Cho Eunil , Song Yonghoon , Lee Sungho , Park Joontae , Nam Sangwook
Published: July 2010

This article proposes an efficient power‐combining architecture with differential and single‐ended power amplifiers (PAs) in a CMOS process. The single‐ended amplifier is added for overall efficiency enhancement. To demonstrate this concept, a CMOS PA using the proposed architecture was fabricated with a 0.13‐μm CMOS technology that delivers 30.6 dBm of output power with 42% drain efficiency and 38% power‐added efficiency at 1.95 GHz. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2214–2217, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25460
Unconditionally stable LOD‐FDTD method based on the simplified sampling biorthogonal algorithm
Authors: Kong Ki‐Bok , Park Seong‐Ook
Published: July 2010

This letter presents an unconditionally stable locally one‐dimensional (LOD) finite‐difference time‐domain method based on the simplified sampling biorthogonal algorithm (SSB‐LOD). The suggested approach requires fewer arithmetic operations than in the SSB‐ADI scheme. This leads to a reduction of CPU time relative to the SSB‐ADI method while equivalent numerical accuracy is retained. The numerical implementation of two parallel conducting plate shows that the CPU time of the SSB‐LOD has been reduced to approximately 85% of that of the SSB‐ADI. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2183–2185, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25461
A new surface wave antenna‐based spoof surface plasmon mechanism
Authors: Shi Haofei , Wei Xingzhan , Zhao Zeyu , Dong Xiaochun , Lu Yueguang , Du Chunlei
Published: July 2010

In this letter, a surface wave antenna based on the excitation of spoof surface plasmon mode at microwave frequency is proposed and demonstrated experimentally to effectively modulate the far field radiation, by integrating with one‐dimensional subwavelength periodic corrugated grooves. Compared with the traditional surface wave antenna, the far field divergence of this spoof surface plasmon antenna exhibits a remarkable red shift. The numerical simulation and experimental data well accord with the predicted results given by grating scattering theory. Consequently, the surface wave antenna can be achieved with unique function and minimized in size by introducing spoof surface plasmon. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2179–2183, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25462
A semicircular band‐notch ultra‐wideband printed antenna based on CSRR
Authors: Yu Zhong‐Wu , Wang Guang‐Ming , Liang Jian‐Gang , Gao Xiang‐Jun
Published: July 2010

In this article, a semicircular band‐notch monopole antenna based on CSRR with band‐notch function is presented. A rectangular slit is cut at the top center of the ground to obtain desired operation frequency bandwidth, and a complementary split‐ring resonator is embedded in feed line to realize band‐notch function. Experiment results show that the proposed antenna has a sharp stop‐band of 4.89 GHz–6.12 GHz and one ultra‐wideband from 2 GHz to 12 GHz. During operated frequency band, the proposed antenna exhibits excellent radiation characteristics. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2387–2390, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25463
Active measurements of a mimo WiMAX‐OFDM based system in reverberation chambers
Authors: Belhouji Adil , Decroze Cyril , Carsenat David , Mouhamadou Moctar , Monediere Thierry
Published: July 2010

Electromagnetic reverberation chambers can be used for multiple‐input multiple‐output (MIMO) systems testing.Currently, the tests focus on parameters such as correlation, diversity gain, efficiency, etc., by using a vector network analyzer. In contrast with these passive tests, a novel way of MIMO systems characterization is described in this article. It consists on evaluating bit error rate (BER) levels of a MIMO WiMAX‐OFDM system according to the Signal‐to‐Noise Ratio (SNR) by establishing an active link between the transmitter and the receiver. The measurement process is set up in a reverberation chamber, where multipath frequency selective channels are emulated. The obtained results are compared to a reference case with single‐input single‐output (SISO) to evaluate the real improvements made by the studied system. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2347–2352, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25465
A topology‐based multilevel scheme for fast integral‐equation methods
Authors: Wang Shumin , Duyn Jeff H.
Published: July 2010

A topology‐based multilevel scheme is proposed for fast integral‐equation simulations. Low‐level subdomains are formed at first by exploring topological connectivity between basis functions. Profile reduction and quad‐tree image compression are then applied to construct a heuristic multilevel scheme from a symbolic rank map. Numerical results verified this approach and demonstrated its computational efficiency. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2195–2198, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25468
A near‐infrared optical fiber sensor for carbon monoxide concentration monitoring
Authors: Zhu Shanying , Chen Youping , Zhang Gang , Sa Jiming
Published: July 2010

An optical fiber sensor presented is capable of monitoring the presence of carbon monoxide (CO) in the exhaust environment.Conventional gas sensor used to detect CO concentration is often difficult to achieve high sensitivity, selectivity, and specificity in presence of a mixture of gases. The design of this sensor using DFB LD as light source and low‐cost near‐infrared components, which make it suitable for using in an exhaust environment, is discussed. The sensor based on spectrum absorption principle is immune to corrosion and poison as it consists of glass and ceramic parts. By using differential construction, it can eliminate the influence of common mode interfering signals caused by the wave of LDs light intension, thermal zero shift, and zero shift of photoelectric device. A national instrument cRIO‐9215 data acquisition card was used to acquire the output voltages and a LabView virtual instrument was used to store and process data. The response of the sensor to carbon dioxide supplied from the standard gas with dry nitrogen as a balancing gas in the laboratory was performed. The experimental results indicated that the sensor has been developed to operate within an exhaust environment and have high sensitivity and stability so it does not suffer from other gases interferences. The lower limit of detection for the sensor was found to be not less than 50 ppm for CO. This can be meeting the requirement of 100 ppm which is to be poisonous to human. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2192–2195, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25469
A monopole antenna with a magneto‐dielectric material and its MIMO application for 700 MHz‐LTE‐band
Authors: Shin Yong‐Sun , Park Seong‐Ook
Published: July 2010

This article presents an antenna with a magneto‐dielectric material and its MIMO application for LTE‐band.The proposed antenna is a folded monopole type and occupies a compact volume of 7.5 × 18.5 × 3.4 mm3. For reducing the size, obtaining the broad bandwidth, and enhancing the isolation performance, the magneto‐dielectric material is applied as a supporter. The parameters of the magneto‐dielectric material are ε′ − jε″= 3.29−j0.09 and μ′ − jμ″ = 2.01−j0.38 at 780 MHz. For evaluations of the MIMO application, the antenna has been measured in reverberation chamber. The Microwave Studio (MWS) is employed for optimizing the design parameters, and the simulated results are well agreed with those of the measured one. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2364–2367, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25470
Printed dipole antenna for WLAN applications
Authors: Sedghi S. , Nourinia J. , Ghobadi Ch.
Published: July 2010

In this article, a novel printed dipole antenna is presented for satisfying wireless local area network (WLAN) applications. The operating frequencies of the proposed antenna are 2.4/5.2/5.8 GHz, which covers WLAN system. Prototypes of the proposed antenna have been constructed and studied experimentally. The measured results show good agreement with the numerical prediction. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2327–2331, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25472
Quad‐band PIFA design for WLAN/satellite applications
Authors: Sim Chow‐Yen‐Desmond , Cheng Yu‐Ting
Published: July 2010

The design of a quad‐band planar inverted‐F antenna (PIFA) for IEEE 802.11 b/g/a WLAN applications and satellite communications system is proposed.To operate at the three resonant modes (2.4/5.2/5.8 GHz) for WLAN operations, a modified PIFA with a truncated corner and an embedded slit on the top rectangular‐shaped radiating element is initially introduced. To further achieve a wide 10 dB impedance bandwidth for satellite communications, a folded radiating element connected to the probe feed is inserted to the PIFA, which leads to a combined triple‐mode resonant frequency operating from 7.5 to 11.27 GHz. Detail procedure of developing this proposed antenna will be discussed, and the simulated data are provided to validate the measurement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2331–2336, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25483
Compact microstrip‐fed ultra‐wideband antenna with novel radiating element
Authors: Naser‐Moghadasi M. , Koohestani Mohsen , Sadeghzadeh R.A.
Published: July 2010

A novel printed monopole antenna with an ultra‐wide bandwidth is presented. The proposed antenna has very compact size (12 × 22 mm2) as well as very simple configuration and easily fed by using a 50 Ω microstrip line. The antenna impedance bandwidth based on S11 < −10 dB is from 3 to 14 GHz, about 130%. A stably omnidirectional radiation patterns over a wide bandwidth is obtained. These features will make the antenna attractive for modern ultra‐wideband applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2267–2269, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25486
Compact high‐gain printed loop‐antenna array integrated into a 5‐GHz WLAN access point
Authors: Hong Tzi‐Chieh , Su Saou‐Wen
Published: July 2010

A printed, planar loop‐antenna array having a compact structure and high‐gain, directional radiation properties for WLAN operation in the 5 GHz band is presented. The antenna‐array design is composed of four‐folded loops arranged to be of 2 × 2 configuration, printed on both sides of a 1.6‐mm thick FR4 substrate, and one system printed circuit board (PCB) serving as an efficient reflector for the loops. The antenna array is set within the boundary of the PCB (size of 50 mm ×65 mm) and stacked there above by a separation distance of 5.4 mm only. That's, the design integrates the system PCB of an access point (AP) into an internal antenna solution for compact outdoor AP applications. The results show that good input matching with voltage standing wave ratio (VSWR) below 1.5 over the 5150–5825 MHz band can be achieved. Directional radiation patterns with peak gain at about 10 dBi were also obtained. Details of the antenna design are described and discussed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2261–2267, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25487
Stacked Neural Network Modeling Applied to the Synthesis of Polyacrylamide‐Based Multicomponent Hydrogels
Authors: Leon Florin , Piuleac Ciprian George , Curteanu Silvia
Published: July 2010

Artificial neural networks are a convenient method of modeling processes for which the analytical estimation is difficult or computationally intensive. Besides the performance on training data, the generalization capability of the resulting neural model is very important, especially for problems such as the one described in this paper, the synthesis of polyacrylamide‐based multicomponent hydrogels, because the prediction of the swelling degree are extremely useful in practice, because it can replace the experiments that necessitate a great amount of materials and time. In order to increase the generalization performance, we use stacked neural networks with a procedure of weight optimization, which prove to be a good choice regarding the accuracy of the results provided by the model.

magnified image
Metric optimized gating for fetal cardiac MRI
Authors: Jansz Michael S. , Seed Mike , van Amerom Joshua F. P. , Wong Derek , Grosse‐Wortmann Lars , Yoo Shi‐Joon , Macgowan Christopher K.
Published: July 2010

Phase‐contrast magnetic resonance imaging can be used to complement echocardiography for the evaluation of the fetal heart. Cardiac imaging typically requires gating with peripheral hardware; however, a gating signal is not readily available in utero. No successful application of existing technologies to human fetal phase‐contrast magnetic resonance imaging has been reported to date in the literature. The purpose of this work is to develop a technique for phase‐contrast magnetic resonance imaging of the fetal heart that does not require measurement of a gating signal. Metric optimized gating involves acquiring data without gating and retrospectively determining the proper reconstruction by optimizing an image metric. The effects of incorrect gating on phase contrast images were investigated, and the time‐entropy of the series of images was found to provide a good measure of the level of corruption. The technique was validated with a pulsatile flow phantom, experiments with adult volunteers, and in vivo application in the fetal population. Images and flow curves from these measurements are presented. Additionally, numerical simulations were used to investigate the degree to which heart rate variability affects the reconstruction process. Metric optimized gating enables imaging with conventional phase‐contrast magnetic resonance imaging sequences in the absence of a gating signal, permitting flow measurements in the great vessels in utero. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Sonnenenergienutzung hat noch Kapazitäten frei
Authors: Jung Udo
Published: July 2010

Hubert Schönberger, Udo Jung, Yves Willers, Christian Hoffmann

Die deutsche chemische Industrie kann vom wachsenden Photovoltaik‐Weltmarkt weiterhin profitieren, wenn sie die Technologieführerschaft bei Materialien der nächsten Solarzellengeneration anstrebt.
Lange bekannt – aber erfolgreich: die Pinakolumlagerung
Authors: Kirsch Stefan
Published: July 2010

Stefan F. Kirsch

Die Pinakolumlagerung ist eine der ältesten Gerüstumlagerungen der organischen Chemie. Moderne Synthesestrategien integrieren sie als zentrales Element und nutzen so ihr hohes synthetisches Potenzial.
Die drei Entdecker der Kernspaltung
Authors: Ellmer Reinhold
Published: July 2010

Reinhold Ellmer Die Spaltung von Atomkernen gehört zu den ganz großen wissenschaftlichen Leistungen. Entdeckt wurde Sie vor 70 Jahren im Dezember 1938.
Der chemische Feldprediger
Authors: Wienhaus Otto , Marx Günter
Published: July 2010

Otto Wienhaus, Günter Marx

Aus Anlass des 200. Geburtstages von Julius Adolph Stöckhardt, einem der wichtigsten Lehrmeister und Wegbereiter der praktischen Chemie im 19. Jahrhundert, veranstalten die TU Chemnitz und die TU Dresden im nächsten Jahr gemeinsam mit der GDCh wissenschaftliche Kolloquien.
Voltammetrische Uranbestimmung als Standard
Authors: Henze Günter
Published: July 2010

Günter Henze

Der Nachweis von Uranspuren im Trinkwasser führte zu kontroversen Diskussionen in der Öffentlichkeit.

Ein elektroanalytisches Normverfahren wird dazu beitragen, die Debatte zu versachlichen.
Die Hans‐R.‐Jenemann‐Stiftung
Authors: Zörlein via Köhler
Published: July 2010

In den letzten 15 Jahren hat die Gesellschaft Deutscher Chemiker sechs Stiftungen eingerichtet, die sie treuhänderisch verwaltet.

Diese unselbständigen gemeinnützigen Stiftungen fördern mit Auszeichnungen und Stipendien den wissenschaftlichen Nachwuchs auf unterschiedlichen Gebieten der Chemie.
Publizieren und verdienen
Authors: Bulmahn Maren
Published: July 2010

Maren Bulmahn

Wissenschaftliche Autoren sind Urheber geistigen Eigentums. Sie profitieren davon, wenn jemand ihre Werke rechtmäßig − also dafür zahlend − kopiert, sendet oder ins Internet stellt. Um an das Geld dafür zu kommen, müssen Autoren ihre Produkte anmelden.
Predictors of alternative antidepressant agent initiation among U. S. veterans diagnosed with depression
Authors: Kim Hyungjin Myra , Zivin Kara , Ganoczy Dara , Pfeiffer Paul , Hoggatt Katherine , McCarthy John F. , Downing Karen , Valenstein Marcia
Published: July 2010

OBJECTIVES

Naturalistic studies comparing differences in risks across antidepressant agents must take into account factors which influence selection of specific agents and may be associated with outcomes. We examined predictors of antidepressant choice among VA patients treated for depression.

METHODS

Retrospective cohort study of VA patients with depression diagnoses and a new start of one of the seven most commonly prescribed antidepressant agents between 1 April 1999 and 30 September 2004 (n = 502 179). We examined the relationship between patient and facility characteristics and new starts of bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, sertraline, and venlafaxine. We also examined factors associated with new starts only among patients starting selective serotonin reuptake inhibitors (SSRIs).

RESULTS

Thirty‐three percent of patients starting mirtazapine had at least three outpatient mental health visits in the prior year, compared to ≤24% of patients prescribed other antidepressants. Patients starting mirtazapine were also most likely to have received at least two other psychotropic medications in the prior year. Of the four SSRIs, 40% of the patients receiving sertraline and only 31% of those receiving fluoxetine were 65 years or older. A comorbid anxiety disorder (other than post‐traumatic stress disorder) was diagnosed in 21% of paroxetine patients compared with ≤15% of other SSRI patients.

CONCLUSION

Choice of antidepressant medication for depressed VA patients was associated with important differences in demographic and clinical variables, including psychiatric illness severity, older age, and likelihood of a comorbid anxiety disorder. These findings emphasize the importance of controlling for selection bias when using observational data to compare risks from or effect of mental health treatments. Copyright © 2010 John Wiley & Sons, Ltd.
Simplified preparation of low polydispersity, low molecular weight poly(D,L‐lactic acid) by liquid/liquid phase separation for drug delivery systems with discussion of molecular weight characterization
Authors: Gu Jian Hua , Huang Yu Jin , Beekman Alice , Goldenberg Merrill
Published: July 2010

Poly(D,L‐lactic acid) (PLA) has been widely used in pharmaceutics and medicine. Low molecular weight (LMW) PLA is especially useful for rapidly degrading biomaterials such as those used for short‐duration drug delivery systems. There is scant information available in the literature regarding the purification and analysis of LMW PLA. In this paper we report (1) a convenient and effective polymer purification/fractionation technique to produce LMW PLA with narrow molecular weight distribution (MWD) and (2) analyses that were used to characterize the molecular weight and MWD of these polymers. A novel, convenient and effective temperature‐induced solution‐phase separation method was developed to produce narrow MWD, LMW (600–2000 g mol−1) PLA. Molecular weights determined using gel permeation chromatography (GPC) with universal calibration, unlike those determined with the commonly used conventional calibration, showed good agreement with those obtained using several independent direct techniques. The phase separation induced by temperature reduction of a polymer in a single solvent system provided a simple and effective technique to produce narrow MWD, LMW PLA polymers. Additional advantages of this technique are: (1) only one solvent is required; (2) the risk of local complete solid polymer precipitation is eliminated; (3) it is reversible and not dependent on the rate of cooling; and (4) use of chlorinated solvents is avoided. This technology may open up a new opportunity for manufacturing LMW polymers with narrow MWD. We also found that GPC with universal calibration is a more accurate method than GPC with the commonly used conventional calibration for characterizing these polymers, and is straightforward to use especially now that on‐line viscosity detectors are widely available. Copyright © 2010 Society of Chemical Industry
The origin of deformation structures in periglacial fluvial sediments of the Wisłok Valley, southeast Poland
Authors: Superson J. , Gębica P. , Brzezińska‐Wójcik T.
Published: July 2010

Numerous deformation structures of various shapes and internal structures (drop‐like and pocket‐like structures, folds, streaks and diapirs) are present in the Weichselian alluvial terrace sands and loams of the Wisłok river (Sandomierz Basin, southeast Poland). A detailed study of the structures leads to the conclusion that they originated from cryostatic pressure, gravitational loading of sediments with reversed density gradient and thermokarst. Under cryostatic pressure, irregular structures formed in channel sands and gravels and wide folds occurred in clayey organic loams during the Greenland Stadial 2 when permafrost expanded. The variable forms and complex structure record the progress of downward displacement interrupted at various stages by water escape. Small sandy load casts and folds in the lower and middle parts of flood rhythmite also formed during the Greenland Stadial 2 when permafrost stabilised. Large deformation structures in the topmost rhythmite layers formed under the weight of overlying channel deposits during the Greenland Interstadial 1 as permafrost degraded. Copyright © 2010 John Wiley & Sons, Ltd.
Healthcare costs within a year of respiratory syncytial virus among medicaid infants
Authors: Palmer Liisa , Hall Caroline B. , Katkin Julie P. , Shi Nianwen , Masaquel Anthony S. , McLaurin Kimmie K. , Mahadevia Parthiv J.
Published: July 2010

Limited research exists on the economic impact of respiratory syncytial virus lower respiratory infection (RSV LRI) among vulnerable infant populations. This study evaluated healthcare costs of full‐term and late‐preterm Medicaid infants with RSV LRI within 1 year of infection. Medicaid administrative claims were used to conduct a retrospective study of infants born 2003–2005. Full‐term and late‐preterm infants <1 year old were assigned to groups based on RSV LRI and unspecified bronchiolitis/pneumonia (UBP) diagnosis codes and stratified by setting of diagnosis. Infants without evidence of RSV LRI/UBP were selected as a comparison group. Economic and clinical outcomes were analyzed descriptively using propensity score weighting, and logged ordinary least squares models were used to examine relationship between RSV and costs incurred within 1 year of infection. RSV LRI and UBP infants, regardless of gestational age or healthcare setting, were more likely to experience respiratory diagnoses of wheezing and infantile asthma versus comparisons. Adjusted and weighted healthcare costs were significantly higher for all groups of RSV LRI and UBP infants relative to comparison infants (P < 0.001). Among late‐preterm infants with inpatient and outpatient RSV, marginal costs compared with controls were $17,465 and $2,158, respectively. Costs for RSV LRI and UBP Medicaid infants are substantial. While much of the costs result from initial RSV episodes, higher post‐episode costs and rates of respiratory events, procedures, and medications in RSV and UBP infants versus comparisons indicate long‐term economic impact from infection and the impact is greater among late‐preterm compared to full‐term infants. Pediatr. Pulmonol. 2010; 45:772–781. © 2010 Wiley‐Liss, Inc.