bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of three polar compounds from Rheum tanguticum by high‐speed countercurrent chromatography with an ethyl acetate/glacial acetic acid/water system
Authors: Chen Tao , Wang Ping , Wang Nana , Sun Chongyang , Yang Xue , Li Hongmei , Zhou Guoying , Li Yulin 
Published: January 2018

AbstractThe separation of polar compounds by high‐speed countercurrent chromatography is still regarded as a challenge. In this study, an efficient strategy for the separation of three polar compounds from Rheum tanguticum has been successfully conducted by using high‐speed countercurrent chromatography. X‐5 macroporous resin chromatography was used for the fast enrichment of the target compounds. Then, the target fraction was directly introduced into high‐speed countercurrent chromatography for separation using ethyl acetate/glacial acetic acid/water (100:1:100, v/v/v) as the solvent system. Consequently, three polar compounds including gallic acid, catechin, and gallic acid 4‐O‐β‐d‐(6′‐O‐galloyl) glucoside were obtained with purities higher than 98%. The results showed glacial acetic acid could be such an appropriate regulator for the ethyl acetate/water system. This study provides a reference for the separation of polar compounds from natural products by high‐speed countercurrent chromatography.
Metal–organic framework based in‐syringe solid‐phase extraction for the on‐site sampling of polycyclic aromatic hydrocarbons from environmental water samples
Authors: Zhang Xiaoqiong , Wang Peiyi , Han Qiang , Li Hengzhen , Wang Tong , Ding Mingyu 
Published: January 2018

AbstractIn‐syringe solid‐phase extraction is a promising sample pretreatment method for the on‐site sampling of water samples because of its outstanding advantages of portability, simple operation, short extraction time, and low cost. In this work, a novel in‐syringe solid‐phase extraction device using metal–organic frameworks as the adsorbent was fabricated for the on‐site sampling of polycyclic aromatic hydrocarbons from environmental waters. Trace polycyclic aromatic hydrocarbons were effectively extracted through the self‐made device followed by gas chromatography with mass spectrometry analysis. Owing to the excellent adsorption performance of metal–organic frameworks, the analytes could be completely adsorbed during one adsorption cycle, thus effectively shortening the extraction time. Moreover, the adsorbed analytes could remain stable on the device for at least 7 days, revealing the potential of the self‐made device for on‐site sampling of degradable compounds in remote regions. The limit of detection ranged from 0.20 to 1.9 ng/L under the optimum conditions. Satisfactory recoveries varying from 84.4 to 104.5% and relative standard deviations below 9.7% were obtained in real samples analysis. The results of this study promote the application of metal–organic frameworks in sample preparation and demonstrate the great potential of in‐syringe solid‐phase extraction for the on‐site sampling of trace contaminants in environmental waters.
Validity evidence as a key marker of quality of technical skill assessment in OTL–HNS
Authors: Labbé Mathilde , Young Meredith , Nguyen Lily H.P. 
Published: January 2018

ObjectiveQuality monitoring of assessment practices should be a priority in all residency programs. Validity evidence is one of the main hallmarks of assessment quality and should be collected to support the interpretation and use of assessment data. Our objective was to identify, synthesize, and present the validity evidence reported supporting different technical skill assessment tools in otolaryngology–head and neck surgery (OTL–HNS).MethodsWe performed a secondary analysis of data generated through a systematic review of all published tools for assessing technical skills in OTL–HNS (n = 16). For each tool, we coded validity evidence according to the five types of evidence described by the American Educational Research Association's interpretation of Messick's validity framework. Descriptive statistical analyses were conducted.ResultsAll 16 tools included in our analysis were supported by internal structure and relationship to variables validity evidence. Eleven articles presented evidence supporting content. Response process was discussed only in one article, and no study reported on evidence exploring consequences.ConclusionWe present the validity evidence reported for 16 rater‐based tools that could be used for work‐based assessment of OTL–HNS residents in the operating room. The articles included in our review were consistently deficient in evidence for response process and consequences. Rater‐based assessment tools that support high‐stakes decisions that impact the learner and programs should include several sources of validity evidence. Thus, use of any assessment should be done with careful consideration of the context‐specific validity evidence supporting score interpretation, and we encourage deliberate continual assessment quality‐monitoring.Level of EvidenceNA. Laryngoscope, 128:2296–2300, 2018
Insulin resistance and the increased risk for smell dysfunction in US adults
Authors: Min Jin‐Young , Min Kyoung‐Bok 
Published: January 2018

ObjectiveOver 24% of older American adults (approximately 14 million) are estimated to have reduced olfactory sensitivity. Previous studies have provided evidence that patients with diabetes mellitus (DM) or its complications are at increased risk of olfactory dysfunction. We therefore investigated whether smell dysfunction was associated with DM‐related biomarkers, including fasting blood glucose, glycohemoglobin, serum insulin, and homeostasis model assessment of insulin sensitivity (HOMA‐IR), in older US adults.MethodsData from 9,678 older adults who had participated in the 2013 to 2014 National Health and Nutrition Examination Survey were available for this study. We used the eight‐item, self‐administered scratch‐and‐sniff smell test (Sensonics, Inc., Haddon Heights, NJ) for assessing smell. Smell dysfunction was defined as the condition with an odor identification score of ≤ 5.ResultsOf the 978 participants, 20% of older adults (n = 193) were defined as having smell dysfunction. After adjustment for potential confounding variables, participants in the highest HOMA‐IR quintile had approximately two‐fold increased odds (odds ratio = 2.25; 95% confidence interval: 1.25–4.05) of smell dysfunction compared with those in the lowest HOMA‐IR quintile. In contrast, the odds of smell dysfunction were not associated with the quintiles for fasting blood glucose, glycohemoglobin (HbA1c), or serum insulin levels.ConclusionWe found a significant association between smell dysfunction and severe insulin resistance in older US adults. Our data suggests that insulin resistance may be mechanistically linked to loss of smell function.Level of Evidence4. Laryngoscope, 128:1992–1996, 2018
Cylinder Lenses for Beam Shaping
Authors: Adams Daniel 
Published: January 2018

AbstractIn the modern world, lasers are a critical part of so many new technologies. Fields like manufacturing, measurement, medical treatments and scientific research and many more all depend on lasers. The quality of the beam in all of these application areas is crucial and can often be the difference between success and failure. Cylinder lenses are commonly used to shape and manipulate a laser beam and any errors or aberrations they introduce will have a direct impact on the beam quality. Manufacturing methods for cylinder lenses differ from traditional spherical optics and because of this, there are additional specifications to be aware of and consider when using them. Without properly specifying and controlling these parameters problems such as uneven line thickness, beam deviation and image rotation can reduce system performance. This article will line out the unique specifications of cylinder lenses that need to be considered in the process of system integration and their potential effect on the performance (Fig. 1).
An appraisal framework of the determinants and consequences of brand happiness
Authors: Schnebelen Stefanie , Bruhn Manfred 
Published: January 2018

AbstractRecent academic discussions about the concept of brand happiness have introduced brand happiness as a promising new branding asset and a key research area. There is scientific evidence that its strong desirability, its characteristic of greatest emotional fulfillment, and its superior power to influence brand behavior qualify brand happiness as an important brand goal and differentiate it from other emotional‐relational concepts (e.g., emotional brand attachment, customer delight). However, there is no evidence on the effectiveness of brand happiness. To provide essential new insights in this research field, the authors theoretically develop an appraisal framework of the determinants and consequences of brand happiness and empirically verify it in four industry sectors. On the cross‐industry level, brand relationship quality, brand self‐relevance, brand goal‐congruence, and actual and ideal brand self‐congruence are confirmed to be important brand appraisal determinants of brand happiness, and pleasantness, fairness, and certainty are confirmed to be important situational appraisal determinants of brand happiness. The behavioral power of brand happiness was supported by showing that brand happiness strongly predicts five coping strategies; namely, the problem‐focused coping strategies of (re‐)purchase intention and price premium, and the emotion‐focused coping strategies of word‐of‐mouth, brand evangelism, and brand forgiveness. On an industry‐specific level, differences are observed regarding the influence of some of the brand appraisal determinants on brand happiness and regarding the influence of some of the situational appraisal determinants on brand happiness across the four analyzed industry sectors.
Effective thermal properties of an isotactic polypropylene (α‐iPP) injection moulded part by a multiscale approach
Authors: Laschet G. , Apel M. , Wipperfürth J. , Hopmann C. , Spekowius M. , Spina R. 
Published: January 2018

AbstractIn injection moulding processes, the melt undergoes a complex deformation and cooling history, which results in an inhomogeneous distribution of crystalline superstructures in semi‐crystalline thermoplastics, which significantly influences their final mechanical and thermal properties. In this paper we describe the determination of local effective thermal properties of a moulded part via a multiscale simulation approach. First a macroscopic filling and heat transfer simulation is performed followed by a microstructure evolution calculation on the micro‐scale. Then, the effective thermal properties are derived via a two‐level homogenization scheme. The results show that the effective thermal conductivity is anisotropic and that it varies asymmetrically over the analysed plate sections.
Modelling approach towards tailored grain structure in laser processing
Authors: Pustal B. , Vossel T. , Bührig‐Polaczek A. , Arntz D. , Haeusler A. , Gillner A. , Poprawe R. , Schwedt A. , Mayer J. , Jansen U. , Schöler C. , Schulz W. 
Published: January 2018

AbstractDue to the change in grain size during laser processing in the heat‐affected zone and the solidifying material, the potential of cracking, surface hardening, and decrease in weldability, corrosion resistance and fatigue life may result. It is shown that through combining state‐of‐the‐art temperature simulation of laser processes with thermo‐mechanical volume averaging grain formation simulation, the resulting grain density can be predicted within the order of magnitude found in the two experiments carried out for laser fusion cutting and spot welding of A356. However, fundamental knowledge about the grain density function during rapid solidification, the prediction of the transition from epitactic growth to globular grains and defined validation experiments are needed in order to provide a realistic virtual microstructure.
Development of an A356 die casting setup for determining the heat transfer coefficient depending on cooling conditions, gap size, and contact pressure
Authors: Wolff N. , Pustal B. , Vossel T. , Laschet G. , Bührig‐Polaczek A. 
Published: January 2018

AbstractIn this paper, the development of an experimental die casting setup to perform simultaneous in‐situ measurements of temperatures, air‐gap formation and contact pressures is presented. The derivation of the resulting heat transfer coefficients between mold and melt is also included. To take the influence of different cooling rates into account, an active die tempering is applied. For the implementation of this experimental setup, a special mold for a rotationally symmetrical test specimen is developed which incorporates the necessary measuring technique and can be adapted to different cooling conditions by means of exchangeable die inserts. Concluding, first results and the corresponding heat transfer coefficients are presented.
Formation of the reaction zone between tin‐copper brazing fillers and aluminum‐silicon‐magnesium alloys: Experiments and thermodynamic analysis
Authors: Bobzin K. , Öte M. , Wiesner S. , Schmidt A. , Apel M. , Berger R. , Aretz A. , Mayer J. 
Published: January 2018

AbstractA primary challenge in brazing is the controlled formation of phases resulting from interactions of elements of the liquid filler metal with those of the base material. The morphology of the brazed joint, which is decisive for the mechanical properties of the joint, is influenced by present elements and process parameters such as brazing temperature and time. Furthermore, the wetting of the base material is a crucial factor in joining of aluminum because of the low wettability of the alumina layer by molten brazing filler metals. In order to remove the alumina and prevent reoxidation of the substrate surface, the brazing process can be conducted in vacuum or inert gas atmosphere. Again, selection of process parameters is crucial for the quality of the brazed seam. In this work, we focus on the influence of the process parameters on the wetting behavior and the formation of aluminum‐copper phases theoretically by means of thermodynamic calculations using a CALPHAD database as well as by means of in‐situ observations in the large‐chamber scanning electron microscope (LC‐SEM) and by brazing experiments. Both the critical temperatures with respect to the wetting and the reaction kinetics as well as the crucial stages of the brazing process and the resulting phases were determined.
Microstructural analysis of germanium modified tin‐copper brazing filler metals for transient liquid phase bonding of aluminium
Authors: Iskandar R. , Schwedt A. , Mayer J. , Rochala P. , Wiesner S. , Öte M. , Bobzin K. , Weirich T.E. 
Published: January 2018

AbstractThe present contribution summarises first results that have been achieved with the new brazing material Sn75Cu20Ge5 (wt‐%) for transient liquid phase (TLP) bonding of aluminium cast alloy AlSi7Mg0.3 (wt‐%). The microstructure of the braze ribbons and the obtained joints have been thoroughly investigated on different length‐scales using scanning and transmission electron microscopy as well. Whereas the braze ribbon material is only composed of beta‐tin, η‐phase (Cu6Sn5) and some germanium rich precipitates, the transient liquid phase joint displays a much more complex microstructure that consist mainly of beta‐tin and different aluminium‐copper and aluminium‐germanium phases. In addition small silicon oxide rods and a hitherto unreported hexagonal aluminium‐copper‐magnesium‐germanium phase with approximated lattice parameters a = 0.7123 nm, c = 2.40 nm have been found in the seam of the joint.
Residual stress measurement in AlSi alloys
Authors: Reisgen U. , Sharma R. , Gach S. , Olschok S. , Francis J. , Bobzin K. , Oete M. , Wiesner S. , Knoch M. , Schmidt A. 
Published: January 2018

AbstractIn this work, the relaxation of residual stresses inside a sample made of the aluminum alloy AlSi7Mg0.3 after tempering is described. The comparison of stress evaluation by X‐ray diffraction and incremental hole drilling method combined with electronic speckle pattern interferometry strain determination gives the opportunity to evaluate micro stresses together with first order macro stresses. Compressive stresses within the surface of a cold worked sample are relaxed by tempering. The X‐ray diffraction evaluation is supported by the analysis of a stress‐free sample through incremental hole drilling method.
An automatable algorithm for measurement of fluid flow during laser fusion cutting using in‐situ trim cut analysis
Authors: Jansen U. , Arntz D. , Petring D. , Schulz W. , Poprawe R. 
Published: January 2018

AbstractIrregularities inside the fluid flow in laser fusion cutting of sheet metals cause quality defects like large striation depths or adhered dross. Trim‐cut analysis is used to measure the flow velocities of the molten material by high speed imaging. The so‐called streak analysis creates a repetitive pattern for multiple melt waves and the angle of these patterns is assignable to specific flow velocities. In this article, a discrete fourier transform is used to automatically determine the spatial distribution of flow velocities. The results show that identifying the velocity domains and assigning them to the parameters of the cutting process and quality characteristics is a promising approach to enhance the understanding and to achieve higher quality cuts.
Beam steering by using a gradient refractive index metamaterial planar lens and a gradient phase metasurface planar lens
Authors: Liu Yahong , Liu Congcong , Jin Xueyu , Zhang Beiyi , Zhang Yinghuai , Zhu Xinqi , Su Bin , Zhao Xiaopeng 
Published: January 2018

AbstractMetamaterials are composed of periodic or quasi‐periodic subwavelength structures, having electric and/or magnetic responses. Metamaterials can arbitrarily tailor the refractive index by artificially tailoring the unit‐cell geometries and dimensions. Recent years, as the two dimensional equivalent of bulk metamaterials, metasurfaces have caused considerable attentions due to the lower profile and simpler to fabricate than bulk metamaterials. Metasurfaces can impart discontinuities on electromagnetic wavefronts and can achieve the arbitrary transmission phase of the whole period range. Metamaterials and metasurfaces have led to the realizations of novel electromagnetic properties and functionalities through tailoring subwavelength structures and integrating functional materials. In this letter, two planar lenses are respectively proposed to control the beam direction of the horn antenna by using a gradient refractive index (GRIN) metamaterial and a gradient phase (GRPH) metasurface. It is shown that the antenna beam direction can be steered by controlling the refractive index of the GRIN metamaterial or the transmission phase of the GRPH metasurface. The differences between the two planar lenses for controlling the antenna beam are illustrated.
Quasi‐fractal antenna system based on asymmetric TEM‐horns nested into each other
Authors: Ashikhmin Aleksandr V. , Negrobov Alexander V. , Pasternak Yuriy G. , Pershin Pavel V. , Fedorov Sergey M. 
Published: January 2018

AbstractIn this article was studied a way to minimize the overall dimensions of a multiband antenna system operating in a number of ultra‐wideband frequency bands using the quasi‐fractal construction principle. The results of an experimental study of the designed antenna element, which is a set of asymmetrical self‐similar TEM‐rupors nested into each other, are presented.
Design of a miniaturized frequency reconfigurable antenna for rectenna in WiMAX and ISM frequency bands
Authors: Naqvi Syed Aftab , Khan Muhammad Saeed 
Published: January 2018

AbstractA frequency reconfigurable miniaturized circular microstrip patch antenna operating in WiMAX (2.5–2.8 GHz) and ISM (2.4–2.48 GHz) frequency bands for the rectenna applications is proposed here. The theory of reconfigurability is employed to switch the operating frequency of the proposed antenna from 2.53 to 2.45 GHz. The electrical length of the radiated circular patch is increased while keeping the overall physical dimension of the antenna constant to provide different current distributions on the radiating patch for the phenomenon of frequency shift. The high permittivity substrate and microstrip transmission‐line feeding mechanism is used to reduce the size of antenna. To demonstrate the reduction in antenna size, a comparison of the proposed antenna with the latest antennas for rectenna applications in literature is presented.
Sext‐band bandpass filter with compactness based on cascading stage of SIRs
Authors: Li Xiaokun , Zhang Yonghong , Tang Yaozong , Xu Jingzhi , Zhang Jie , Yong Fan 
Published: January 2018

AbstractUtilizing cascading stage of SIRs (CSIRs), a miniaturized sext‐band bandpass filter is investigated and fabricated. Purposely, two‐section SIRs with high/low impedance‐ratio are built up for not only enough spurious frequency for sext‐band application, but excellent control on these frequencies. In addition, architecture of CSIR, namely number and arrangement of employed SIRs, is optimized for widening potential frequency range with good response in each passband. Meanwhile, on account of transversal signal interaction concept together with mixed electric magnetic coupling of CSIRI,II, transmission zeros (TZs) and transmission poles (TPs) can be excited alternately. Since coupling is introduced by embedding CSIRs without adding any other structures, configuration of proposed design is compact. Moreover, tapped position of 0° feeding branch can be adjusted for improving filter performance. Therefore, design of miniaturized sext‐band bandpass filter becomes available. Good agreement between simulated and measured results validates the design method.
A new CPW‐fed broadband circularly polarized printed monopole antenna for UWB application
Authors: Zhai Huiqing , Yang Dong , Xi Lei , Feng Dan 
Published: January 2018

AbstractA new coplanar‐waveguide (CPW) ‐fed circularly polarized (CP) printed monopole Antenna with a simply structure is presented. By utilizing an asymmetrical T‐shaped matching stub as feedline and nesting two strips of inverted‐L‐shaped and rectangle into both sides of the ground plane along the edge of the substrate, good impedance matching and CP radiation can be obtained. The proposed antenna is tested and its measured result is fairly identical with the simulated result. It exhibits that the impedance bandwidth for S11<−10 dB is as large as 115% (3.1–11.9 GHz) which can apply to the UWB communication. The 3‐dB axial‐ratio bandwidth (ARBW) reaches 62.6% from 3.4 GHz to 6.5 GHz.
Low group delay variation 3‐10 GHz 65 nm CMOS stacked power amplifier with 18.1 dBm peak 1 dB compression output power
Authors: Polge David , Ghiotto Anthony , Kerhervé Eric , Fabre Pascal 
Published: January 2018

AbstractA 3‐10 GHz stacked power amplifier (PA) with low group delay variation and 18.1 dBm peak 1 dB compression output power (P1dB) in 65 nm CMOS bulk technology is presented. It is intended for ultra‐wideband or multiband telecommunication, sensing, and instrumentation systems operating in the 3‐10 GHz frequency range situated in the S, C, and X bands. Its design, based on stacked transistors allowing a supply voltage as high as 4 V to achieve a high 1 dB compression output power, is detailed. In the 3–10 GHz band, the proposed PA provides measured gain, P1dB, and maximum power added efficiency (PAEmax) of 12.65 ± 1.25 dB, 16 ± 2.1 dBm, and 20.15 ± 7.55%, respectively. In addition, in its frequency range of operation, this PA achieves an excellent measured group delay variation of ±21.55 ps. To the authors’ knowledge, this wideband PA offers the lowest group delay variation in this frequency range of operation.