bluuebunny/crossref_metadata_2025 huggingface dataset:
Strong sub-terahertz surface waves generated on a metal wire by high-intensity laser pulses
Authors: Tokita Shigeki , Sakabe Shuji , Nagashima Takeshi , Hashida Masaki , Inoue Shunsuke
Published: February 2015

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip. This is particularly useful for applications that require high-field pulses. However, the generation of strong terahertz surface waves on a wire waveguide remains a challenge. Here, ultrafast field propagation along a metal wire driven by a femtosecond laser pulse with an intensity of 1018 W/cm2 is characterized by femtosecond electron deflectometry. From experimental and numerical results, we conclude that the field propagating at the speed of light is a half-cycle transverse-magnetic surface wave excited on the wire and a considerable portion of the kinetic energy of laser-produced fast electrons can be transferred to the sub-surface wave. The peak electric field strength of the surface wave and the pulse duration are estimated to be 200 MV/m and 7 ps, respectively.
Crmp4 deletion promotes recovery from spinal cord injury by neuroprotection and limited scar formation
Authors: Nagai Jun , Kitamura Yoshiteru , Owada Kazuki , Yamashita Naoya , Takei Kohtaro , Goshima Yoshio , Ohshima Toshio
Published: February 2015

Axonal outgrowth inhibitors and scar formation are two major obstacles to central nervous system (CNS) repair. No target molecule that regulates both axonal growth and scarring has been identified. Here we identified collapsin response mediator protein 4 (CRMP4), a common mediator of inhibitory signals after neural injury, as a crucial factor that contributes to both axonal growth inhibition and scarring after spinal cord injury (SCI). We found increases in the inhibitory and toxic forms of CRMP4 in injured spinal cord. Notably, CRMP4 expression was evident in inflammatory cells as well as in neurons after spinal cord transection. Crmp4−/− mice displayed neuroprotection against SCI and reductions in inflammatory response and scar formation. This permissive environment for axonal growth due to CRMP4 deletion restored locomotor activity at an unusually early phase of healing. These results suggest that deletion of CRMP4 is a unique therapeutic strategy that overcomes two obstacles to CNS repair after SCI.
3D morphometric analysis of fossil canid skulls contradicts the suggested domestication of dogs during the late Paleolithic
Authors: Drake Abby Grace , Coquerelle Michael , Colombeau Guillaume
Published: February 2015

Whether dogs were domesticated during the Pleistocene, when humans were hunter-gatherers, or during the Neolithic, when humans began to form permanent settlements and engage in agriculture, remains controversial. Recently discovered Paleolithic fossil skulls, Goyet dated 31,680 +/− 250 YBP and Eliseevichi MAE 447/5298 dated 13,905 +/− 55 YBP, were previously identified as dogs. However, new genetic studies contradict the identification of these specimens as dogs, questioning the validity of traditional measurements used to morphologically identify canid fossil skulls. We employ 3D geometric morphometric analyses to compare the cranial morphology of Goyet and Eliseevichi MAE to that of ancient and modern dogs and wolves. We demonstrate that these Paleolithic canids are definitively wolves and not dogs. Compared to mesaticephalic (wolf-like breeds) dog skulls, Goyet and Eliseevichi MAE, do not have cranial flexion and the dorsal surface of their muzzles has no concavity near the orbits. Morphologically, these early fossil canids resemble wolves and thus no longer support the establishment of dog domestication in the Paleolithic.
FTIR imaging of structural changes in visceral and subcutaneous adiposity and brown to white adipocyte transdifferentiation
Authors: Kucuk Baloglu Fatma , Garip Sebnem , Heise Sebastian , Brockmann Gudrun , Severcan Feride
Published: February 2015

FTIR microspectroscopy coupled with UCP1 immunohistological staining enables the detection of obesity-related molecular alterations and transdifferentiations in visceral and subcutaneous adipose tissues in spontaneously obese mice lines.
Biosynthetic selenoproteins with genetically-encoded photocaged selenocysteines
Authors: Rakauskaitė Rasa , Urbanavičiūtė Giedrė , Rukšėnaitė Audronė , Liutkevičiūtė Zita , Juškėnas Robertas , Masevičius Viktoras , Klimašauskas Saulius
Published: February 2015

The first general approach for the biosynthesis of selenoproteins that contain photocaged selenocysteine residues at genetically-encoded positions is described.
Mesoporous polyoxometalate cluster–crosslinked organosilica frameworks delivering exceptionally high photocatalytic activity
Authors: Koutsouroubi Eirini D. , Xylouri Alexandra K. , Armatas Gerasimos S.
Published: February 2015

Mesoporous polyoxometalate (POM)-based organosilica frameworks with high catalytic activity, 3D open-pore structure, and uniform pores are prepared via a surfactant-assisted co-polymerization of organically-modified POM clusters with ethane-bridged silsesquioxane linkers.
Physico-chemical changes in Ca, Sr and Al-doped La–Mn–O perovskites upon thermochemical splitting of CO2via redox cycling
Authors: Gálvez M. E. , Jacot R. , Scheffe J. , Cooper T. , Patzke G. , Steinfeld A.
Published: February 2015

Thermochemical CO2-splitting via redox cycling of Ca, Sr and Al-doped La–Mn perovskites induces irreversible changes in the texture and chemical composition of these oxides.
A new photoactive Ru(ii)tris(2,2′-bipyridine) templated Zn(ii) benzene-1,4-dicarboxylate metal organic framework: structure and photophysical properties
Authors: Whittington Christi L. , Wojtas Lukasz , Gao Wen-Yang , Ma Shengqian , Larsen Randy W.
Published: February 2015

It has now been demonstrated that Ru(ii)tris(2,2′-bipyridine) (RuBpy) can be utilized to template the formation of new metal organic framework (MOF) materials containing crystallographically resolved RuBpy clusters with unique photophysical properties.
Novel heteroleptic Ru(ii) complexes: synthesis, characterization and application in dye-sensitized solar cells
Authors: Marotta Gabriele , Kumar Ch. Pavan , Lobello Maria Grazia , Cavazzini Francesca , Salvatori Paolo , Ganesh Koyyada , Nazeeruddin Mohammad Khaja , Chandrasekharam Malapaka , De Angelis Filippo
Published: February 2015

Photovoltaic efficiencies of 6–8%, comparable with N719, were obtained with six novel Ru(ii) heteroleptic dyes.
Preparation of copper nanoparticle-improved polyamide 6 composites by an in situ solution route with cupric oxide as the metallic copper source and investigation of their properties
Authors: Xu Qijie , Li Xiaohong , Zhang Zhijun
Published: February 2015

Preparation of polyamide 6–Cu nanocomposites possessing remarkable properties by an in-situ solution route.
Zinc amidoisophthalate complexes and their catalytic application in the diastereoselective Henry reaction
Authors: Karmakar Anirban , Guedes da Silva M. Fátima C. , Hazra Susanta , Pombeiro Armando J. L.
Published: February 2015

5-Propionamidoisophthalic acid and 5-benzamidoisophthalic acid are used to synthesize new zinc(ii) complexes which act as heterogeneous catalysts for the diastereoselective nitroaldol (Henry) reaction.
Recent advances in graphene and its metal-oxide hybrid nanostructures for lithium-ion batteries
Authors: Srivastava Manish , Singh Jay , Kuila Tapas , Layek Rama K. , Kim Nam Hoon , Lee Joong Hee
Published: February 2015

This review highlights the recent progress in graphene and graphene-based metal-oxide hybrids for use as electrode materials in lithium-ion batteries.
Highly sulfonated co-polyimides containing cross-linkable hydrophobic tetrafluorostyrol side-groups for proton exchange membranes
Authors: Yao Hongyan , Feng Pengju , Liu Peng , Liu Baijun , Zhang Yunhe , Guan Shaowei , Jiang Zhenhua
Published: February 2015

Highly sulfonated co-polyimides containing cross-linked hydrophobic side-groups showed improved comprehensive performance.
Sugar-functionalized water-soluble pillar[5]arene and its host–guest interaction with fullerene
Authors: Li Hui , Chen Qi , Schönbeck Christian , Han Bao-Hang
Published: February 2015

The host–guest interaction between a neutral water-soluble pillar[5]arene containing ten sugar moieties and C60was investigated.
Ca3Co4O9/polycrystalline Al2O3: an effective template for c-axis oriented layered cobaltate thin films by chemical solution deposition
Authors: Wei Renhuai , Tang Xianwu , Yang Jie , Dai Jianming , Liang Changhao , Song Wenhai , Zhu Xuebin , Sun Yuping
Published: February 2015

Ca3Co4O9/polycrystalline Al2O3 thin film is an effective template for growth of c-axis oriented layered cobaltate thin films.
Effects of PVDF/SiO2 hybrid ultrafiltration membranes by sol–gel method for the concentration of fennel oil in herbal water extract
Authors: Huang Xin , Zhang Jing , Wang Weiping , Liu Yaodong , Zhang Zhibing , Li Lei , Fan Wenling
Published: February 2015

PVDF/SiO2 membranes by sol–gel were characterized and ultrafiltration performance of fennel oil in water extract through them was effectively improved.
Facile synthesis of Fe3O4/hierarchical-Mn3O4/graphene oxide as a synergistic catalyst for activation of peroxymonosulfate for degradation of organic pollutants
Authors: Yang Bo , Tian Zhang , Wang Bin , Sun Zebin , Zhang Li , Guo Yaopeng , Li Haizhen , Yan Shiqiang
Published: February 2015

Well-characterized Fe3O4/hierarchical Mn3O4/rGO composites exhibited high catalytic ability towards the degradation of MB using PMS as an oxidant.
Synthesis, characterization, and application of Fe3O4@SiO2–NH2nanoparticles
Authors: Liu Feng , Niu Fuge , Peng Ning , Su Yujie , Yang Yanjun
Published: February 2015

Synthesis of Fe3O4@SiO2–NH2nanoparticles by a mild and time-saving method and the application in separation of ovotransferrin were studied.
Spectroscopic studies of keto–enol tautomeric equilibrium of azo dyes
Authors: Rauf M. A. , Hisaindee S. , Saleh N.
Published: February 2015

Keto–enol tautomeric equilibrium of an azo dye is shifted to the keto form as the solvent polarity is increased.
Prussian blue analogues as heterogeneous catalysts for epoxidation of styrene
Authors: Liang Yanling , Yi Chaoyong , Tricard Simon , Fang Jian , Zhao Jihua , Shen Weiguo
Published: February 2015

Prussian blue analogues are high performance catalyst for low toxicity, lower dosage reactions, simple preparation processes and cheap.
Two-photon absorption and two-photon circular dichroism of hexahelicene derivatives: a study of the effect of the nature of intramolecular charge transfer
Authors: Díaz Carlos , Vesga Yuly , Echevarria Lorenzo , Stará Irena G. , Starỳ Ivo , Anger Emmanuel , Shen Chengshuo , El Sayed Moussa Mehdi , Vanthuyne Nicolas , Crassous Jeanne , Rizzo Antonio , Hernández Florencio E.
Published: February 2015

Effect of the strength and nature of the extension of the π-electronic delocalization on TPA and TPCD of helicenes derivatives.
Studying the supercapacitive behavior of a polyaniline/nano-structural manganese dioxide composite using fast Fourier transform continuous cyclic voltammetry
Authors: Shabani Shayeh Javad , Norouzi Parviz , Ganjali Mohammad Reza
Published: February 2015

In this work the supercapacitive behavior of electrochemically synthesized polyaniline/nano-structural manganese dioxide composite (PANI/NsMnO2) on a glassy carbon electrode (GCE) was studied.
Polyelectrolytes-assisted layer-by-layer assemblies of graphene oxide and dye on glass substrate
Authors: Aslandaş Ayşe Merve , Onganer Yavuz , Meral Kadem
Published: February 2015

Pyronin Y (PyY) and graphene oxide (GO) were assembled on a glass substrate by the electrostatic layer-by-layer (LbL) method with the assistance of polyelectrolytes.
Printable poly(methylsilsesquioxane) dielectric ink and its application in solution processed metal oxide thin-film transistors
Authors: Wu Xinzhou , Chen Zheng , Zhou Teng , Shao Shuangshuang , Xie Meilan , Song Mingshun , Cui Zheng
Published: February 2015

Printable thermally cross-linkable PMSQ dielectric ink and its application in GPTMS modified IGZO thin film transistors.
Programming macro-materials from DNA-directed self-assembly
Authors: Zhang Xuena , Wang Rong , Xue Gi
Published: February 2015

DNA-mediated self-assembly of nanoparticles into designed materials with novel properties and highly ordered crystal structures.
Facile synthesis of nitrogen and fluorine co-doped carbon materials as efficient electrocatalysts for oxygen reduction reactions in air-cathode microbial fuel cells
Authors: Meng Kai , Liu Qin , Huang Yiyin , Wang Yaobing
Published: February 2015

Nitrogen and fluorine co-doped carbon black (BP-NF) was prepared via the direct pyrolysis of a mixture of polytetrafluoroethylene (PTFE) and BP-2000 under an ammonium atmosphere for high efficient ORR electrocatalysis in the air-cathode of microbial fuel cells.
Photoinduced triplet-state electron transfer of platinum porphyrin: a one-step direct method for sensing iodide with an unprecedented detection limit
Authors: Masih Dilshad , Aly Shawkat M. , Alarousu Erkki , Mohammed Omar F.
Published: February 2015

Herein, we report for the first time the photoinduced triplet-state electron transfer of Pt(ii)TMPyP as an easy, rapid, environmentally friendly, ultra-sensitive and economical method for the determination of iodide in the aqueous phase.
Preparation of porous silicon/carbon microspheres as high performance anode materials for lithium ion batteries
Authors: Ren Wenfeng , Zhang Zailei , Wang Yanhong , Tan Qiangqiang , Zhong Ziyi , Su Fabing
Published: February 2015

Porous silicon/carbon microspheres assembled with fine carbon particles and silicon nanoparticles show improved electrochemical performance as anode materials for lithium ion batteries.
The tunable electronic structure and mechanical properties of halogenated silicene: a first-principles study
Authors: Zhang Wei-Bing , Song Zhi-Bo , Dou Liu-Ming
Published: February 2015

Halogenated silicene, with enhanced stability compared with silicene, presents a moderate and tunable direct gap with small carrier effective mass and improved elastic properties.
Facile synthesis of luminescent silver nanoparticles and fluorescence interactions with blue-emitting polyarylene ether nitrile
Authors: Jia Kun , Wang Pan , Yuan Liting , Zhou Xuefei , Chen Wenjin , Liu Xiaobo
Published: February 2015

In this work, fluorescent silver nanoparticles with average size of 6 nm were synthesized in an organic phase via a facile one-step reaction.
A cross-dipole stacking molecule of an anthracene derivative: integrating optical and electrical properties
Authors: Liu Jie , Meng Lingqiang , Zhu Weigang , Zhang Congcong , Zhang Hantang , Yao Yifan , Wang Zongrui , He Ping , Zhang Xiaotao , Wang Ying , Zhen Yonggang , Dong Huanli , Yi Yuanping , Hu Wenping
Published: February 2015

The present work showed the synthesis of a cross stacking molecule. And both semiconducting properties and solid state luminescence were achieved for its micro/nano fibers.
Palladium(ii)-catalysed ortho-arylation of N-benzylpiperidines
Authors: Tan Peng Wen , Haughey Maxwell , Dixon Darren J.
Published: February 2015

A simple and mild protocol for saturated N-heterocycle directed ortho-C–H arylation under Pd-catalysis is reported.
An anomalous trade-off effect on the properties of smart ortho-functional benzoxazines
Authors: Zhang Kan , Ishida Hatsuo
Published: February 2015

A series of ortho-difunctional benzoxazine monomers containing amide, imide and amide–imide groups have been synthesized in order to obtain basic design rules toward preparing higher performance polybenzoxazoles based on smart benzoxazine chemistry.
Ordered short channel mesoporous silica modified with 1,3,5-triazine–piperazine as a versatile recyclable basic catalyst for cross-aldol, Knoevenagel and conjugate addition reactions with isatins
Authors: Gupta Naveen , Roy Tamal , Ghosh Debashis , Abdi Sayed H. R. , Kureshy Rukhsana I. , Khan Noor-ul H. , Bajaj Hari C.
Published: February 2015

A recyclable triazine–piperazine immobilized silica supported material was explored as a heterogeneous catalyst for indole skeletal synthesized from isatins at RT.
Synthesis of high strength monolithic alumina aerogels at ambient pressure
Authors: Cao Fengchao , Ren Lili , Li Xueai
Published: February 2015

Mechanically strong monolithic alumina aerogels were obtained via ambient pressure drying by incorporating attapulgite (ATP) and alumina sol.
Four-fold concentration of sucrose in sugarcane juice through energy efficient forward osmosis using sea bittern as draw solution
Authors: Mondal Dibyendu , Nataraj Sanna Kotrappanavar , Rami Reddy Alamaru Venkata , Ghara Krishna K. , Maiti Pratyush , Upadhyay Sumesh C. , Ghosh Pushpito K.
Published: February 2015

Clarified sugarcane juice was efficiently dewatered through the spontaneous process of Forward Osmosis (FO) employing sea bittern as draw solution.
Rhodium-catalyzed C–H functionalization-based approach to eight-membered lactams
Authors: Wu Shangze , Zeng Rong , Fu Chunling , Yu Yihua , Zhang Xue , Ma Shengming
Published: February 2015

Fused tricyclic skeleton in one shot: a RhIIIcatalyzed formal [4 + 2 + 2] cyclization ofN-pivaloyloxybenzamides1with 1,6-allene-enes2adding two cycles to the benzene ring compatible with ambient air and moisture with a tolerance of many synthetic useful functional groups at room temperature have been developed.
An Investigation of Measurement Equivalence in Hearing Response Scales: Refinement of a Questionnaire for Use in Hearing Screening
Authors: Chenault Michelene , Anteunis Lucien , Kremer Bernd , Berger Martijn
Published: February 2015

Purpose

Questionnaires used in hearing screening should be short and demonstrate measurement equivalence across groups defined by hearing impairment and hearing aid experience. The measurement equivalence of 2 scales addressingfunctionality(experienced hearing ability) andsocial hearing(social barriers due to hearing problems) was investigated.

Method

Measurement equivalence was assessed using the differential item functioning and differential test framework within item response theory. Three comparisons were considered: (a) persons with normal hearing versus persons with hearing impairment either owning or not owning a hearing aid; (b) hearing aid users versus individuals who do not use hearing aids; (c) hearing aid users versus persons with hearing impairment who do not use a hearing aid. A protocol of differential item detection was applied consisting of ordinal regression and the log-likelihood ratio test to flag suspect items, followed by applying the log-likelihood ratio test using anchor items (items not suspect of differential item functioning).

Results

The 11-item functionality scale was reduced to 9 items, whereas the 10-item social hearing scale was reduced to 7 items.

Conclusions

Applying the differential item functioning framework resulted in shorter questionnaires displaying measurement equivalence relative to hearing impairment and hearing aid use without loss of reliability.
It Is Time to Rethink Central Auditory Processing Disorder Protocols for School-Aged Children
Authors: DeBonis David A.
Published: February 2015

Purpose

The purpose of this article is to review the literature that pertains to ongoing concerns regarding the central auditory processing construct among school-aged children and to assess whether the degree of uncertainty surrounding central auditory processing disorder (CAPD) warrants a change in current protocols.

Method

Methodology on this topic included a review of relevant and recent literature through electronic search tools (e.g., ComDisDome, PsycINFO, Medline, and Cochrane databases); published texts; as well as published articles from theJournal of the American Academy of Audiology; theAmerican Journal of Audiology; theJournal of Speech, Language, and Hearing Research; andLanguage, Speech, and Hearing Services in Schools.

Results

This review revealed strong support for the following: (a) Current testing of CAPD is highly influenced by nonauditory factors, including memory, attention, language, and executive function; (b) the lack of agreement regarding the performance criteria for diagnosis is concerning; (c) the contribution of auditory processing abilities to language, reading, and academic and listening abilities, as assessed by current measures, is not significant; and (d) the effectiveness of auditory interventions for improving communication abilities has not been established.

Conclusions

Routine use of CAPD test protocols cannot be supported, and strong consideration should be given to redirecting focus on assessing overall listening abilities. Also, intervention needs to be contextualized and functional. A suggested protocol is provided for consideration. All of these issues warrant ongoing research.
Experiential Instruction in Graduate-Level Preparation of Speech-Language Pathology Students in Outer and Middle Ear Screening
Authors: Serpanos Yula C. , Senzer Deborah
Published: February 2015

Purpose

This study presents a piloted training model of experiential instruction in outer and middle ear (OE-ME) screening for graduate speech-language pathology students with peer teaching by doctor of audiology (AuD) students.

Method

Six individual experiential training sessions in screening otoscopy and tympanometry were conducted for 36 graduate-level speech-language pathology students led by a supervised AuD student.

Results

Postexperiential training, survey outcomes from 24 speech-language pathology students revealed a significant improvement (
p
= .01) in perceptions of attaining adequate knowledge and comfort in performing screening otoscopy (handheld and video otoscopy) and tympanometry. In a group of matched controls who did not receive experiential training in OE-ME screening (
n
= 24), ratings on the same learning outcomes survey in otoscopy and tympanometry were significantly poorer (
p
= .01) compared with students who did receive experiential training.

Conclusion

A training model of experiential instruction for speech-language pathology students by AuD students improved learning outcomes, illustrating its promise in affecting clinical practices. The instructional model also meets the Council on Academic Accreditation in Audiology and Speech-Language Pathology (CAA; American Speech-Language-Hearing Association, 2008) and American Speech-Language-Hearing Association (2014) Certificate of Clinical Competence (ASHA CCC) standards for speech-language pathology in OE-ME screening and CAA (2008) and ASHA (2012) CCC standards in the supervisory process for audiology.
List Memory in Young Adults With Language Learning Disability
Authors: Sheng Li , Byrd Courtney T. , McGregor Karla K. , Zimmerman Hannah , Bludau Kadee
Published: February 2015

Purpose

The purpose of this study was to characterize the verbal memory limitations of young adults with language learning disability (LLD).

Method

Sixteen young adults with LLD and 34 age- and education-matched controls with typical language participated in a Deese–Roediger–McDermott (DRM; Deese, 1959; Roediger & McDermott, 1995) list recall experiment. Participants listened to 12-item word lists that converged on a nonpresented critical item (e.g.,rain) semantically (umbrella,drench,weather,hail), phonologically (train,main,ran,wren), or dually in a hybrid list (umbrella,train,drench,main) and recalled words in no particular order. Group comparisons were made on veridical recall (i.e., words that were presented) and false recall of nonpresented critical items. Recall performance was analyzed by list type and list position to examine potential differences in the quality of memorial processes.

Results

The LLD group produced fewer veridical recalls than the controls. Both groups demonstrated list type and list position effects in veridical recall. False recall of the critical items was comparable in the 2 groups and varied by list type in predictable ways.

Conclusion

Young adults with LLD have verbal memory limitations characterized by quantitatively low levels of accurate recall. Qualitative patterns of recall are similar to those of unaffected peers. Therefore, the memory problem is characterized by limited capacity; memorial processes appear to be intact.
Psychometric Characteristics of Single-Word Tests of Children's Speech Sound Production
Authors: Flipsen Peter , Ogiela Diane A.
Published: February 2015

Purpose

Our understanding of test construction has improved since the now-classic review by McCauley and Swisher (1984). The current review article examines the psychometric characteristics of current single-word tests of speech sound production in an attempt to determine whether our tests have improved since then. It also provides a resource that clinicians may use to help them make test selection decisions for their particular client populations.

Method

Ten tests published since 1990 were reviewed to determine whether they met the 10 criteria set out by McCauley and Swisher (1984), as well as 7 additional criteria.

Results

All of the tests reviewed met at least 3 of McCauley and Swisher's (1984) original criteria, and 9 of 10 tests met at least 5 of them. Most of the tests met some of the additional criteria as well.

Conclusions

The state of the art for single-word tests of speech sound production in children appears to have improved in the last 30 years. There remains, however, room for improvement.
Bilinear discriminant feature line analysis for image feature extraction
Authors: Yan Lijun , Li Jun‐Bao , Zhu Xiaorui , Pan Jeng‐Shyang , Tang Linlin
Published: February 2015

A novel bilinear discriminant feature line analysis (BDFLA) is proposed for image feature extraction. The nearest feature line (NFL) is a powerful classifier. Some NFL‐based subspace algorithms were introduced recently. In most of the classical NFL‐based subspace learning approaches, the input samples are vectors. For image classification tasks, the image samples should be transformed to vectors first. This process induces a high computational complexity and may also lead to loss of the geometric feature of samples. The proposed BDFLA is a matrix‐based algorithm. It aims to minimise the within‐class scatter and maximise the between‐class scatter based on a two‐dimensional (2D) NFL. Experimental results on two‐image databases confirm the effectiveness.
Gain enhancement of bow‐tie antenna using fractal wideband artificial magnetic conductor ground
Authors: Zhong Yong‐Wei , Yang Guo‐Min , Zhong Li‐Rong
Published: February 2015

A novel fractal wideband artificial magnetic conductor (AMC) structure is designed as the ground plane of a printed bow‐tie antenna for gain enhancement and low profile. The origin printed bow‐tie antenna is operated in the range from 1.67 to 2.06 GHz for a VSWR <2. The AMC structure consists of 6 × 9 first‐order fractal unit cells that are made up of four circles and four smaller circles, and the ±90° reflection phase band is 1.1–3.03 GHz. Both the AMC ground plane and bow‐tie antenna are fabricated and measured. The distance between the antenna and the AMC is reduced to one‐eighth of the wavelength in free space at 1.7 GHz. The experimental results show that the composite antenna has a wide bandwidth from 1.64 to 1.94 GHz, with a relative frequency bandwidth of 16.7%.
Colour‐reproduction algorithm for transmitting variable video frames and its application to capsule endoscopy
Authors: Khan Tareq , Shrestha Ravi , Imtiaz Md. Shamin , Wahid Khan A.
Published: February 2015

Presented is a new power‐efficient colour generation algorithm for wireless capsule endoscopy (WCE) application. In WCE, transmitting colour image data from the human intestine through radio frequency (RF) consumes a huge amount of power. The conventional way is to transmit all R, G and B components of all frames. Using the proposed dictionary‐based colour generation scheme, instead of sending all R, G and B frames, first one colour frame is sent followed by a series of grey‐scale frames. At the receiver end, the colour information is extracted from the colour frame and then added to colourise the grey‐scale frames. After a certain number of grey‐scale frames, another colour frame is sent followed by the same number of grey‐scale frames. This process is repeated until the end of the video sequence to maintain the colour similarity. As a result, over 50% of RF transmission power can be saved using the proposed scheme, which will eventually lead to a battery life extension of the capsule by 4–7 h. The reproduced colour images have been evaluated both statistically and subjectively by professional gastroenterologists. The algorithm is finally implemented using a WCE prototype and the performance is validated using an ex‐vivo trial.
Improvement of lithium adsorption capacity by optimising the parameters affecting synthesised ion sieves
Authors: Zandevakili Saeed , Ranjbar Mohammad , Ehteshamzadeh Maryam
Published: February 2015

Recent study has shown that the spinel type of MnO2 nanoparticles have a required capacity for lithium extraction from liquid resources. The low lithium adsorption capacity of synthesised ion sieves was found to be an important limiting parameter for their use in industrial applications. Therefore, increasing the uptake capacity of different ion sieves by studying the effect of six effective parameters, involving lithium salt compound, manganese salt compound, oxidising reagent, calcination temperature, heating time and Li/Mn mol ratio, on the synthesised ion sieves was investigated. Hence, in this reported work, a specific approach based on the L9 (34) Taguchi orthogonal array was employed to evaluate these parameters and to optimise them in two separate stages. Also, the relative importance of each factor was determined using analysis of variance. Although, all mentioned parameters had a significant effect on lithium uptake capacity, the oxidising reagent and the lithium salt compound were the most effective factors. Also, an appropriate ion sieve with a lithium adsorption capacity of more than 9 mmol g−1 was synthesised for the first time.
On quasi-periodic solutions for generalized Boussinesq equation with quadratic nonlinearity
Authors: Shi Yanling , Xu Junxiang , Xu Xindong
Published: February 2015

In this paper, one-dimensional generalized Boussinesq equation: utt − uxx + (u2 + uxx)xx = 0 with boundary conditions ux(0, t) = ux(π, t) = uxxx(0, t) = uxxx(π, t) = 0 is considered. It is proved that the equation admits a Whitney smooth family of small-amplitude quasi-periodic solutions with 2-dimensional Diophantine frequencies. The proof is based on an infinite dimensional Kolmogorov-Arnold-Moser theorem and Birkhoff normal form.
Microscopic dynamics of water around unfolded structures of barstar at room temperature
Authors: Pal Somedatta , Chakraborty Kaushik , Khatua Prabir , Bandyopadhyay Sanjoy
Published: February 2015

The breaking of the native structure of a protein and its influences on the dynamic response of the surrounding solvent is an important issue in protein folding. In this work, we have carried out atomistic molecular dynamics simulations to unfold the protein barstar at two different temperatures (400 K and 450 K). The two unfolded forms obtained at such high temperatures are further studied at room temperature to explore the effects of nonuniform unfolding of the protein secondary structures along two different pathways on the microscopic dynamical properties of the surface water molecules. It is demonstrated that though the structural transition of the protein in general results in less restricted water motions around its segments, but there are evidences of formation of new conformational motifs upon unfolding with increasingly confined environment around them, thereby resulting in further restricted water mobility in their hydration layers. Moreover, it is noticed that the effects of nonuniform unfolding of the protein segments on the relaxation times of the protein–water (PW) and the water–water (WW) hydrogen bonds are correlated with hindered hydration water motions. However, the kinetics of breaking and reformation of such hydrogen bonds are found to be influenced differently at the interface. It is observed that while the effects of unfolding on the PW hydrogen bond kinetics seem to be minimum, but the kinetics involving the WW hydrogen bonds around the protein segments exhibit noticeably heterogeneous characteristics. We believe that this is an important observation, which can provide valuable insights on the origin of heterogeneous influence of unfolding of a protein on the microscopic properties of its hydration water.
Effect of the mounting membrane on shape in inertial confinement fusion implosions
Authors: Nagel S. R. , Haan S. W. , Rygg J. R. , Barrios M. , Benedetti L. R. , Bradley D. K. , Field J. E. , Hammel B. A. , Izumi N. , Jones O. S. , Khan S. F. , Ma T. , Pak A. E. , Tommasini R. , Town R. P. J.
Published: February 2015

The performance of Inertial Confinement Fusion targets relies on the symmetric implosion of highly compressed fuel. X-ray area-backlit imaging is used to assess in-flight low mode 2D asymmetries of the shell. These time-resolved images of the shell exhibit features that can be related to the lift-off position of the membranes used to hold the capsule within the hohlraum. Here, we describe a systematic study of this membrane or “tent” thickness and its impact on the measured low modes for in-flight and self-emission images. The low mode amplitudes of the shell in-flight shape (P2 and P4) are weakly affected by the tent feature in time-resolved, backlit data. By contrast, time integrated self-emission images along the same axis exhibit a reversal in perceived P4 mode due to growth of a feature seeded by the tent, which can explain prior inconsistencies between the in-flight P4 and core P4, leading to a reevaluation of optimum hohlraum length. Simulations with a tent-like feature normalized to match the feature seen in the backlit images predict a very large impact on the capsule performance from the tent feature.
Second derivatives for approximate spin projection methods
Authors: Thompson Lee M. , Hratchian Hrant P.
Published: February 2015

The use of broken-symmetry electronic structure methods is required in order to obtain correct behavior of electronically strained open-shell systems, such as transition states, biradicals, and transition metals. This approach often has issues with spin contamination, which can lead to significant errors in predicted energies, geometries, and properties. Approximate projection schemes are able to correct for spin contamination and can often yield improved results. To fully make use of these methods and to carry out exploration of the potential energy surface, it is desirable to develop an efficient second energy derivative theory. In this paper, we formulate the analytical second derivatives for the Yamaguchi approximate projection scheme, building on recent work that has yielded an efficient implementation of the analytical first derivatives.
High brightness diode-pumped organic solid-state laser
Authors: Zhao Zhuang , Mhibik Oussama , Nafa Malik , Chénais Sébastien , Forget Sébastien
Published: February 2015

High-power, diffraction-limited organic solid-state laser operation has been achieved in a vertical external cavity surface-emitting organic laser (VECSOL), pumped by a low-cost compact blue laser diode. The diode-pumped VECSOLs were demonstrated with various dyes in a polymer matrix, leading to laser emissions from 540 nm to 660 nm. Optimization of both the pump pulse duration and output coupling leads to a pump slope efficiency of 11% for a DCM based VECSOLs. We report output pulse energy up to 280 nJ with 100 ns long pump pulses, leading to a peak power of 3.5 W in a circularly symmetric, diffraction-limited beam.
Synchrotron x-ray diffraction study of micro-patterns obtained by spatially selective hydrogenation of GaAsN
Authors: Ciatto G. , Pettinari G. , Balakrishnan N. , Berenguer F. , Patanè A. , Birindelli S. , Felici M. , Polimeni A.
Published: February 2015

We report a comparative synchrotron radiation x-ray diffraction study of GaAs1−yNy micro-structures obtained by two different patterning methods: spatially selective H incorporation achieved by using H-opaque masks and spatially selective H removal attained by laser writing. These methods are emerging as original routes for fabrication of micro- and nano-structures with in-plane modulation of the bandgap energy. By measuring the out-of-plane and in-plane lattice parameters, we find that for both patterning approaches the largest part of the micro-structure volume remains tensile-strained and pseudomorphic to the substrate, regardless of the compressive-strained hydrogenated barriers. However, a larger lattice disorder is probed in the laser-written micro-structures and attributed to partial removal of H and/or strain changes at the micro-structure boundaries. This larger lattice disorder is confirmed by photoluminescence studies.
Enhanced charge recombination due to surfaces and twin defects in GaAs nanostructures
Authors: Brown Evan , Sheng Chunyang , Shimamura Kohei , Shimojo Fuyuki , Nakano Aiichiro
Published: February 2015

Power conversion efficiency of gallium arsenide (GaAs) nanowire (NW) solar cells is severely limited by enhanced charge recombination (CR) at sidewall surfaces, but its atomistic mechanisms are not well understood. In addition, GaAs NWs usually contain a high density of twin defects that form a twin superlattice, but its effects on CR dynamics are largely unknown. Here, quantum molecular dynamics (QMD) simulations reveal the existence of an intrinsic type-II heterostructure at the (110) GaAs surface. Nonadiabatic quantum molecular dynamics (NAQMD) simulations show that the resulting staggered band alignment causes a photoexcited electron in the bulk to rapidly transfer to the surface. We have found orders-of-magnitude enhancement of the CR rate at the surface compared with the bulk value. Furthermore, QMD and NAQMD simulations show unique surface electronic states at alternating (111)A and (111)B sidewall surfaces of a twinned [111]-oriented GaAs NW, which act as effective CR centers. The calculated large surface recombination velocity quantitatively explains recent experimental observations and provides microscopic understanding of the underlying CR processes.
High efficiency single Ag nanowire/p-GaN substrate Schottky junction-based ultraviolet light emitting diodes
Authors: Wu Y. , Hasan T. , Li X. , Xu P. , Wang Y. , Shen X. , Liu X. , Yang Q.
Published: February 2015

We report a high efficiency single Ag nanowire (NW)/p-GaN substrate Schottky junction-based ultraviolet light emitting diode (UV-LED). The device demonstrates deep UV free exciton electroluminescence at 362.5 nm. The dominant emission, detectable at ultralow (<1 μA) forward current, does not exhibit any shifts when the forward current is increased. External quantum efficiency (EQE) as high as 0.9% is achieved at 25 μA current at room temperature. Experiments and simulation analysis show that devices fabricated with thinner Ag NWs have higher EQE. However, for very thin Ag NWs (diameter < 250 nm), this trend breaks down due to heat accumulation in the NWs. Our simple device architecture offers a potentially cost-effective scheme to fabricate high efficiency Schottky junction-based UV-LEDs.
Magnetic properties of Fe-Mn-Pt for heat assisted magnetic recording applications
Authors: Park Jihoon , Hong Yang-Ki , Kim Seong-Gon , Gao Li , Thiele Jan-Ulrich
Published: February 2015

We calculate the electronic structures of FePt and Fe0.5Mn0.5Pt using first-principles calculations based on density functional theory within the local-spin-density approximation. The Curie temperature (Tc) was calculated by mean field approximation. Composition dependence of the Cure temperature (Tc(x)) of Fe1−xMnxPt was used to identify a composition to meet the desired Tc in the range of 600–650 K. The identified composition (0.0294 ≤ x ≤ 0.0713) gives saturation magnetization (Ms) in the range of 1041–919 emu/cm3 and magnetocrystalline anisotropy constant (K) in the range of 9.96–8.36 × 106 J/m3 at 0 K. Temperature dependent M(T) and K(T) of Fe1−xMnxPt (0.0294 ≤ x ≤ 0.0713) were calculated using the Brillouin function and Callen-Callen experimental relation, respectively. Fe1−xMnxPt (0.0294 ≤ x ≤ 0.0713) shows 930–800 emu/cm3 of Ms and 7.18–5.61 × 106 J/m3 of K at 300 K, thereby satisfying desired magnetic properties for heat-assisted magnetic recording media to achieve 4 Tb/in.2 areal density.
Artificial layered perovskite oxides A(B0.5B′0.5)O3 as potential solar energy conversion materials
Authors: Chen Hungru , Umezawa Naoto
Published: February 2015

Perovskite oxides with a d0 electronic configuration are promising photocatalysts and exhibit high electron mobilities. However, their band gaps are too large for efficient solar energy conversion. On the other hand, transition metal cations with partially filled dn electronic configurations give rise to visible light absorption. In this study, by using hybrid density functional theory calculations, it is demonstrated that the virtues of the two categories of materials can be combined in perovskite oxide A(B0.5B′0.5)O3 with a layered B-site ordering along the [001] direction. The electronic structures of the four selected perovskite oxide compounds, La(Ti0.5Ni0.5)O3, La(Ti0.5Zn0.5)O3, Sr(Nb0.5Cr0.5)O3, and Sr(Nb0.5Fe0.5)O3 are calculated and discussed.
A nanoscale vacuum-tube diode triggered by few-cycle laser pulses
Authors: Higuchi Takuya , Maisenbacher Lothar , Liehl Andreas , Dombi Péter , Hommelhoff Peter
Published: February 2015

We propose and demonstrate a nanoscale vacuum-tube diode triggered by few-cycle near-infrared laser pulses. It represents an ultrafast electronic device based on light fields, exploiting near-field optical enhancement at surfaces of two metal nanotips. The sharper of the two tips displays a stronger field-enhancement, resulting in larger photoemission yields at its surface. One laser pulse with a peak intensity of 4.7 × 1011 W/cm2 triggers photoemission of ∼16 electrons from the sharper cathode tip, while emission from the blunter anode tip is suppressed by 19 dB to ∼0.2 electrons per pulse. Thus, the laser-triggered current between two tips exhibit a rectifying behavior, in analogy to classical vacuum-tube diodes. According to the kinetic energy of the emitted electrons and the distance between the tips, the total operation time of this laser-triggered nanoscale diode is estimated to be below 1 ps.
Optical and structural characteristics of high indium content InGaN/GaN multi-quantum wells with varying GaN cap layer thickness
Authors: Yang J. , Zhao D. G. , Jiang D. S. , Chen P. , Zhu J. J. , Liu Z. S. , Le L. C. , Li X. J. , He X. G. , Liu J. P. , Yang H. , Zhang Y. T. , Du G. T.
Published: February 2015

The optical and structural properties of InGaN/GaN multi-quantum wells (MQWs) with different thicknesses of low temperature grown GaN cap layers are investigated. It is found that the MQW emission energy red-shifts and the peak intensity decreases with increasing GaN cap layer thickness, which may be partly caused by increased floating indium atoms accumulated at quantum well (QW) surface. They will result in the increased interface roughness, higher defect density, and even lead to a thermal degradation of QW layers. An extra growth interruption introduced before the growth of GaN cap layer can help with evaporating the floating indium atoms, and therefore is an effective method to improve the optical properties of high indium content InGaN/GaN MQWs.
Identification of luminescent surface defect in SiC quantum dots
Authors: Dai Dejian , Guo Xiaoxiao , Fan Jiyang
Published: February 2015

The surface defect that results in the usually observed blue luminescence in the SiC quantum dots (QDs) remains unclear. We experimentally identify that the surface defect C=O (in COO) is responsible for this constant blue luminescence. The HO···C=O [n(OH) → π*(CO)] interaction between the hydroxyl and carbonyl groups changes the energy levels of C=O and makes the light absorption/emission arise at around 326/438 nm. Another surface defect (Si–Si) is identified and its light absorption contributes to both C=O-related luminescence and quantum-confinement luminescence of the SiC QDs.
Hysteresis-free high-temperature precise bimorph actuators produced by direct bonding of lithium niobate wafers
Authors: Shur V. Ya. , Baturin I. S. , Mingaliev E. A. , Zorikhin D. V. , Udalov A. R. , Greshnyakov E. D.
Published: February 2015

The current paper presents a piezoelectric bimorph actuator produced by direct bonding of lithium niobate wafers with the mirrored Y and Z axes. Direct bonding technology allowed to fabricate bidomain plate with precise positioning of ideally flat domain boundary. By optimizing the cutting angle (128° Y-cut), the piezoelectric constant became as large as 27.3 pC/N. Investigation of voltage dependence of bending displacement confirmed that bimorph actuator has excellent linearity and hysteresis-free. Decrease of the applied voltage down to mV range showed the perfect linearity up to the sub-nm deflection amplitude. The frequency and temperature dependences of electromechanical transmission coefficient in wide temperature range (from 300 to 900 K) were investigated.
Non-Arrhenius conduction due to the interface-trap-induced disorder in X-doped amorphous In-X-Zn oxides thin-film transistors
Authors: Benwadih Mohammed , Chroboczek J. A. , Ghibaudo Gérard , Coppard Romain , Vuillaume Dominique
Published: February 2015

Thin film transistors, with channels composed of In-X-Zn oxides, IXZO, with X dopants: Ga, Sb, Be, Mg, Ag, Ca, Al, Ni, and Cu, were fabricated and their I-V characteristics were taken at selected temperatures in the 77 K < T < 300 K range. The low field mobility, μ, and the interface defect density, NST, were extracted from the characteristics for each of the studied IXZOs. At higher T, the mobility follows the Arrhenius law with an upward distortion, increasing as T is lowered, gradually transforming into the exp [-(T0/T)1/4] variation. We showed that μ(T, NST) follows μ0 exp[-Eaeff(T,NST)/kT], with T-dependent effective activation energy Eaeff(T, NST) accounts for the data, revealing a linear correlation between Eaeff and NST at higher T. Temperature variation of Eaeff(T, NST) was evaluated using a model assuming a random distribution of conduction mobility edge Ec values in the oxides, stemming from spatial fluctuations induced by disorder in the interface traps distribution. For a Gaussian distribution of Ec, the activation energy Eaeff(T, NST) varies linearly with 1/T, which accounts satisfactorily for the data obtained on all the studied IXZOs. The model also shows that Eaeff(T, NST) is a linear function of NST at a fixed T, which explains the exponential decrease of μ with NST.
Gas-dynamic acceleration of laser-ablation plumes: Hyperthermal particle energies under thermal vaporization
Authors: Morozov A. A. , Evtushenko A. B. , Bulgakov A. V.
Published: February 2015

The expansion of a plume produced by low-fluence laser ablation of graphite in vacuum is investigated experimentally and by direct Monte Carlo simulations in an attempt to explain hyperthermal particle energies for thermally vaporized materials. We demonstrate that the translation energy of neutral particles, ∼2 times higher than classical expectations, is due to two effects, hydrodynamic plume acceleration into the forward direction and kinetic selection of fast particles in the on-axis region. Both effects depend on the collision number within the plume and on the particles internal degrees of freedom. The simulations allow ablation properties to be evaluated, such as ablation rate and surface temperature, based on time-of-flight measurements. Available experimental data on kinetic energies of various laser-produced particles are well described by the presented model.