bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of proton irradiation on mechanical properties of low‐density polyethylene/multiwalled carbon nanotubes composites
Authors: Rui Erming , Yang Jianqun , Li Xingji , Ma Guoliang
Published: February 2014

The mechanical properties of low‐density polyethylene/multiwalled carbon nanotubes (LDPE/MWCNTs) composites without and with 170 keV proton irradiation were studied by tensile tests. Mechanisms of changes of mechanical properties were examined by means of small angle X‐ray scattering (SAXS), wide angle X‐ray diffraction (WAXD), Raman spectroscopy, and scanning electron microscopy (SEM). The tensile curve of LDPE exhibits three characteristic regions, while those for LDPE/MWCNTs composites only give the first and the second ones. The tensile curves of all samples with 170 keV proton irradiation have no obvious yield phenomenon. The addition of MWCNTs increases the ultimate tensile strength and decreases the elongation at break. Moreover, the ultimate tensile strengths of both LDPE and LDPE/MWCNTs composites with 170 keV proton irradiation are enhanced, and the elongations at break for them are decreased. Based on the analyses of SAXS, WAXD, Raman spectroscopy, and SEM, both the loading of MWCNTs and the proton irradiation can change the mechanical properties of LDPE/MWCNTs composites by a number of factors including the homogeneous distribution of MWCNTs in LDPE matrix, the aberrance zone between MWCNTs, and LDPE matrix, the interaction between MWCNTs and LDPE matrix, and the crystallinities of samples. POLYM. COMPOS., 36:278–286, 2015. © 2014 Society of Plastics Engineers
Correlation of on‐wafer 400 V dynamic behavior and trap characteristics of GaN‐HEMTs
Authors: Imada T. , Piedra D. , Kikkawa T. , Palacios T.
Published: February 2014

A method for identifying the critical traps for the dynamic behavior of gallium nitride high electron mobility transistors (GaN‐HEMTs) is described. This method provides information on where the critical traps are located in the horizontal direction. At first, the on‐wafer 400 V dynamic behavior of a GaN‐HEMT was measured. Acceptor‐like trap behavior with 0.14 eV activation energy was observed using conductance analysis. Next, trap characterization was achieved using the capacitance and series conductance transients of a comb‐style Schottky barrier diode after electrical stress. Several different biases were applied to determine the locations of the detected traps, because depletion area edges can change upon imposition of different biases. Notably, 0.18 eV acceptor‐like trap behavior below the Schottky electrode, 0.44 eV donor‐like trap behavior in the access region, and 0.5eV acceptor‐like trap behavior in access region were observed. By correlating these diode results with HEMT results, it was concluded that the critical trap behavior likely occurs below the gate electrode in HEMT. As a conclusion, the information obtained with this method should provide useful information for the improvement of device processes.
Improvement on InGaN‐based light emitting diodes using p‐GaN layer grown at low temperature in full N2 environment
Authors: Deng Zhen , Jiang Yang , Zuo Peng , Fang Yutao , Ma Ziguang , Jia Haiqiang , Zhou Junming , Chen Hong
Published: February 2014

A method is suggested to improve the characteristics of light emitting diodes (LEDs) by using p‐GaN structure with heavily Mg‐doping grown at low temperature in full N2 environment. The LED exhibits a 36.4% enhancement in light output power (LOP) at 222 A cm−2 due to the higher hole concentration as compared to the normal p‐GaN layer. Meanwhile, the experimental results prove that the optimized LED structure shows reduced efficiency droop behavior, smaller peak wavelength blueshift and narrower electroluminescence (EL) spectrum broadening.
Fragmentation study of noscapine derivatives under electrospray conditions
Authors: Nagy Lajos , Kuki Ákos , Szabó Katalin , Sipos Attila , Zsuga Miklós , Kéki Sándor
Published: February 2014

RATIONALE

Noscapine is a biologically active molecule with anticancer activity among other things. Therefore, from an analytical point of view, knowledge of the mass spectrometric properties of noscapine and its derivatives is essential. The goal of the present study is to describe the collision‐induced dissociation behavior of noscapine and its seven derivatives ionized by protons and lithium and sodium ions.

METHODS

Protonated noscapines were produced using electrospray ionization (ESI) mass spectrometry (MS). For the tandem mass spectrometry (MS/MS) experiments nitrogen was used as the collision gas and the collision energies were varied in the range of 1–53 eV (in the laboratory frame).

RESULTS

The ESI‐MS/MS measurements showed that the MS/MS spectra of the protonated noscapines were more informative than the lithiated and sodiated ones. Based on the MS/MS studies, the main fragmentation channels of the protonated noscapines were found to be the loss of water and the loss of a meconine moiety from the precursor ion; furthermore, methyl transfer was also observed in the MS/MS spectra.

CONCLUSIONS

The MS/MS study of the protonated noscapines gives more structural information than that of lithiated and sodiated noscapines. However, the most important fragmentation channel, which leads to the formation of the most intensive product ion in the MS/MS spectra, is independent of the ionization agent. Copyright © 2014 John Wiley & Sons, Ltd.
Cryptanalysis of a certificateless identification scheme
Authors: Chin Ji‐Jian , Behnia Rouzbeh , Heng Swee‐Huay , Phan Raphael C‐W.
Published: February 2014

In 2013, Dehkordi and Alimoradi proposed a certificateless identification scheme using supersingular elliptic curves. This proposal came independent of the parallel work of Chin et al. in proposing the first known security models for certificateless identification with provable security. In this paper, we show that there are some design flaws in the Dehkordi–Alimoradi scheme, which lead one to conclude that their scheme is insecure. Copyright © 2014 John Wiley & Sons, Ltd.
TOA: a tag‐owner‐assisting RFID authentication protocol toward access control and ownership transfer
Authors: Xie Wei , Xie Lei , Zhang Chen , Wang Qiang , Wang Chao , Tang Chaojing
Published: February 2014

This paper addresses radio frequency identification (RFID) authentication and ownership transfer in offline scenarios. Four typical related works are reviewed in detail. A series of shortcomings and vulnerabilities of them are pointed out. A new RFID authentication protocol based on a novel tag‐owner‐assisting architecture is proposed, making a tag's owner an essential participant of the RFID authentication process. The proposed protocol is distinguished from existing works in providing ownership transfer, access control, and mutual authentication without any centralized database neither on a backend server nor in a reader. The security of the proposed protocol is verified by using automated validation of Internet security protocols and applications tool. The proposed protocol is server‐less, simple, scalable, untraceable, and device‐independent. These features are simultaneously achieved in a single RFID authentication protocol for the first time. Copyright © 2014 John Wiley & Sons, Ltd.
Psychological and Work Stress Assessment of Patients following Angioplasty or Heart Surgery: Results of 1‐year Follow‐up Study
Authors: Fiabane Elena , Giorgi Ines , Candura Stefano M. , Argentero Piergiorgio
Published: February 2014

The aim of this study was to explore changes in subjective psychological health and perceived work stress among patients who returned to work (RTW) after a multidisciplinary cardiac rehabilitation (CR) following cardiac interventions.

A total of 108 patients were evaluated at the beginning of their CR, at 6 and 12 months after discharge. Self‐report questionnaires were used to assess depression, anxiety, illness perception and work stress at each time stage.

Results showed reports of depressive symptoms significantly decreased (p < 0.05) and subjective mental (p = 0.001) and physical health (p < 0.001) improved over time. Patients revealed a decrease in Type A behaviour pattern (p < 0.001) and in job satisfaction levels (p = 0.01), greater internal locus of control (p < 0.01) and increased use of the coping strategy ‘Involvement’ (p < 0.01).

Major findings are that cardiac patients had an improvement in subjective psychological health and did not perceive increased work stress after their RTW. Patients' psychological health and work stress need to be assessed during the CR and should be also carefully monitored after the RTW in order to identify patients' psychological and work‐related barriers and facilitate a safe and successful work reintegration. Copyright © 2014 John Wiley & Sons, Ltd.
Mislocalization of K+ channels causes the renal salt wasting in EAST/SeSAME syndrome
Authors: Tanemoto Masayuki , Abe Takaaki , Uchida Shunya , Kawahara Katsumasa
Published: February 2014

The Kir4.1/Kir5.1 channel mediates basolateral K+ recycling in renal distal tubules; this process is critical for Na+ reabsorption at the tubules. Mutations in Kir4.1 are associated with EAST/SeSAME syndrome, a genetic disorder characterized by renal salt wasting. In this study, we found that MAGI‐1 anchors Kir4.1 channels (Kir4.1 homomer and Kir4.1/Kir5.1 heteromer) and contributes to basolateral K+ recycling. The Kir4.1 A167V mutation associated with EAST/SeSAME syndrome caused mistrafficking of the mutant channels and inhibited their expression on the basolateral surface of tubular cells. These findings suggest mislocalization of the Kir4.1 channels contributes to renal salt wasting.
Mix and match: Investigating heteromeric and heterotypic gap junction channels in model systems and native tissues
Authors: Koval Michael , Molina Samuel A. , Burt Janis M.
Published: February 2014

This review is based in part on a roundtable discussion session: “Physiological roles for heterotypic/heteromeric channels” at the 2013 International Gap Junction Conference (IGJC 2013) in Charleston, South Carolina. It is well recognized that multiple connexins can specifically co‐assemble to form mixed gap junction channels with unique properties as a means to regulate intercellular communication. Compatibility determinants for both heteromeric and heterotypic gap junction channel formation have been identified and associated with specific connexin amino acid motifs. Hetero‐oligomerization is also a regulated process; differences in connexin quality control and monomer stability are likely to play integral roles to control interactions between compatible connexins. Gap junctions in oligodendrocyte:astrocyte communication and in the cardiovascular system have emerged as key systems where heterotypic and heteromeric channels have unique physiologic roles. There are several methodologies to study heteromeric and heterotypic channels that are best applied to either heterologous expression systems, native tissues or both. There remains a need to use and develop different experimental approaches in order to understand the prevalence and roles for mixed gap junction channels in human physiology.
The Trial of Li Zhuang: Chinese Lawyers’ Collective Action against Populism
Authors: Liu Sida , Liang Lily , Halliday Terence C.
Published: February 2014

The Chinese judicial system has long been influenced by a populist legal ideology that prioritizes public accountability and political legitimacy over professional autonomy. In recent years, however, the Chinese legal profession has begun to mobilize collectively, albeit episodically, to challenge this populism. Drawing on legal documents, interviews, media reports, and online discussions, this paper provides a scholarly analysis of the Li Zhuang case in 2009−11, in which the fate of an individual criminal defence lawyer was linked with the main ideological conflict in China’s legal system and the highest-level political struggles in the Chinese state. It demonstrates that, although populism remains an intimidating force in China’s judicial practice, lawyers, scholars, and other legal professionals may be laying a foundation for collective solidarity to pursue professionalism through their mobilization against populism.
Diplomacy at the Edge: Split Interests in the Roe Embassy to the Mughal Court
Authors: Mishra Rupali
Published: February 2014

As the first official English ambassador to the Mughal court, Sir Thomas Roe found himself at the outer reaches of English knowledge, experience, and influence in the early seventeenth century. This article examines the difficult position Roe felt himself to occupy, triangulating between the different interests he represented—his own interests, those of the East India Company that employed him, and those of the Crown that accredited him. Roe's letters revealed his difficulties in conducting what he saw as the essential tasks of the ambassador, and his limited success in establishing his status and authority both at the Mughal court and over the Company factors in India. As someone at the forefront of English overseas activities in the early seventeenth century, Roe's experiences shed light on the lived experience of English expansion. His case demonstrates the difficulties of adapting the tools of Tudor-Stuart statecraft to England's widening global reach.
Colonial Humanitarian? Thomas Gore Browne and the Taranaki War, 1860–61
Authors: Storey Kenton Scott
Published: February 2014

The New Zealand Wars of the 1860s have traditionally been associated with the popularity of antagonistic racial discourses and the growing influence of scientific racism. Building upon recent research into the resonance of humanitarian racial discourses in this period, this article reconsiders the experience of Governor Thomas Gore Browne during the Taranaki War, 1860–61. The Taranaki War was a global news event that precipitated fierce debates within both New Zealand and Great Britain over the war's origins and the rights of indigenous Maori. This article reveals how both Browne and his wartime critics defined themselves as the true defenders of Maori rights. This general usage of humanitarian racial discourses was encouraged by perceptions of metropolitan surveillance, New Zealand's prominence within networks of imperial communication, and an onus to administrate Maori with justice.
Host reproductive status and reproductive performance of a parasite: offspring quality and trade-offs in a flea parasitic on a rodent
Authors: DLUGOSZ ELIZABETH M. , DOWNS CYNTHIA J. , KHOKHLOVA IRINA S. , DEGEN A. ALLAN , KRASNOV BORIS R.
Published: February 2014

We investigated offspring quality in fleas (Xenopsylla ramesis) feeding on non-reproducing, pregnant or lactating rodents (Meriones crassus) and asked whether (a) quality of flea offspring differs dependent on host reproductive status; (b) fleas trade off offspring quantity for quality; and (c) quality variables are inter-correlated. Emergence success was highest when parents exploited pregnant hosts, while development time was longest when parents exploited lactating hosts. Male offspring from fleas fed on non-reproductive and pregnant hosts were larger than those from lactating hosts whereas female offspring from fleas fed on pregnant hosts were larger than those from both lactating and non-reproductive hosts. Male offspring survived under starvation the longest when their parents exploited lactating hosts and the shortest when their parents exploited pregnant hosts. Female offspring of parents that exploited lactating hosts survived under starvation longer than those that exploited non-reproductive and pregnant hosts. Emergence success and development time decreased as mean number of eggs laid by mothers increased. Fleas that were larger and took longer to develop lived significantly longer under starvation. These results indicate the presence of a trade-off between offspring quantity and quality in fleas exploiting female Sundevall's jird in varying reproductive condition but this trade-off depended on the quality trait considered.
A symptom profile of depression among Asian Americans: is there evidence for differential item functioning of depressive symptoms?
Authors: Kalibatseva Z. , Leong F. T. L. , Ham E. H.
Published: February 2014

Background

Theoretical and clinical publications suggest the existence of cultural differences in the expression and experience of depression. Measurement non-equivalence remains a potential methodological explanation for the lower prevalence of depression among Asian Americans compared to European Americans.

Method

This study compared DSM-IV depressive symptoms among Asian Americans and European Americans using secondary data analysis of the Collaborative Psychiatric Epidemiology Surveys (CPES). The Composite International Diagnostic Interview (CIDI) was used for the assessment of depressive symptoms. Of the entire sample, 310 Asian Americans and 1974 European Americans reported depressive symptoms and were included in the analyses. Measurement variance was examined with an item response theory differential item functioning (IRT DIF) analysis.

Results

χ2analyses indicated that, compared to Asian Americans, European American participants more frequently endorsed affective symptoms such as ‘feeling depressed’, ‘feeling discouraged’ and ‘cried more often’. The IRT analysis detected DIF for four out of the 15 depression symptom items. At equal levels of depression, Asian Americans endorsed feeling worthless and appetite changes more easily than European Americans, and European Americans endorsed feeling nervous and crying more often than Asian Americans.

Conclusions

Asian Americans did not seem to over-report somatic symptoms; however, European Americans seemed to report more affective symptoms than Asian Americans. The results suggest that there was measurement variance in a few of the depression items.
Reduced Wu and generalized Simon invariants for spatial graphs
Authors: FLAPAN ERICA , FLETCHER WILL , NIKKUNI RYO
Published: February 2014

We introduce invariants of graphs embedded in S3 which are related to the Wu invariant and the Simon invariant. Then we use our invariants to prove that certain graphs are intrinsically chiral, and to obtain lower bounds for the minimal crossing number of particular embeddings of graphs in S3.
Delirium, agitation, and symptom distress within the final seven days of life among cancer patients receiving hospice care
Authors: de la Cruz Maxine , Noguera Antonio , San Miguel-Arregui Maria Teresa , Williams Janet , Chisholm Gary , Bruera Eduardo
Published: February 2014

Objective:

Knowledge of symptom prevalence and adequate assessment of such symptoms at the end of life is important in clinical practice. We determined the frequency and severity of symptom distress and delirium using the Edmonton Assessment Scale (ESAS) and the Memorial Delirium Assessment Scale (MDAS) and evaluated the clinical utility of the Nursing Delirium Screening Scale (Nu-DESC) as scored by a caregiver as a screening tool for delirium.

Method:

We conducted a secondary analysis of the data from a previous randomized controlled trial on parenteral hydration at the end of life of patients admitted to home hospice. Only patients that had assessments within the last week of life were included. We collected the ESAS, MDAS, Nu-DESC, and Richmond Agitation Sedation Scale (RASS) results. The sensitivity and specificity of the Nu-DESC were then calculated.

Results:

Some 78 of 261 patients were included in our study, 62 (80%) of which had moderate-to-severe symptoms corresponding to an ESAS score >4. These symptoms include: 73 (94%) anorexia, 63 (81%) fatigue, 56 (73%) drowsiness, 58 (75%) decreased well-being, and 39 (51%) pain. Delirium was diagnosed in 34 (44%) of patients using the MDAS. The Nu-DESC was found to have a sensitivity of 35%, a specificity of 80%, a positive predictive value (PPV) of 58%, and an negative predictive value (NPV) of 61% when used by caregivers.

Significance of Results:

Hospice patients at the end of life have a high rate of symptom distress and delirium. The Nu-DESC is not a reliable tool for screening delirium when scoring is conducted by a caregiver. Our study illustrates the need for routine use of assessment tools to improve care.
Copy Number Variation Distribution in Six Monozygotic Twin Pairs Discordant for Schizophrenia
Authors: Castellani Christina A. , Awamleh Zain , Melka Melkaye G. , O'Reilly Richard L. , Singh Shiva M.
Published: February 2014

We have evaluated copy number variants (CNVs) in six monozygotic twin pairs discordant for schizophrenia. The data from Affymetrix® Human SNP 6.0 arrays™ were analyzed using Affymetrix® Genotyping Console™, Partek® Genomics Suite™, PennCNV, and Golden Helix SVS™. This yielded both program-specific and overlapping results. Only CNVs called by Affymetrix Genotyping Console, Partek Genomics Suite, and PennCNV were used in further analysis. This analysis included an assessment of calls in each of the six twin pairs towards identification of unique CNVs in affected and unaffected co-twins. Real time polymerase chain reaction (PCR) experiments confirmed one CNV loss at 7q11.21 that was found in the affected patient but not in the unaffected twin. The results identified CNVs and genes that were previously implicated in mental abnormalities in four of the six twin pairs. It includedPYY(twin pairs 1 and 5),EPHA3(twin pair 3),KIAA1211L(twin pair 4), andGPR139(twin pair 5). They represent likely candidate genes and CNVs for the discordance of four of the six monozygotic twin pairs for this heterogeneous neurodevelopmental disorder. An explanation for these differences is ontogenetic de novo events that differentiate in the monozygotic twins during development.
Crenarchaeal heterotrophy in salt marsh sediments
Authors: Seyler Lauren M , McGuinness Lora M , Kerkhof Lee J
Published: February 2014

Mesophilic Crenarchaeota (also known as Thaumarchaeota) are ubiquitous and abundant in marine habitats. However, very little is known about their metabolic function in situ. In this study, salt marsh sediments from New Jersey were screened via stable isotope probing (SIP) for heterotrophy by amending with a single 13C-labeled compound (acetate, glycine or urea) or a complex 13C-biopolymer (lipids, proteins or growth medium (ISOGRO)). SIP incubations were done at two substrate concentrations (30–150 μm; 2–10 mg ml−1), and 13C-labeled DNA was analyzed by terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes. To test for autotrophy, an amendment with 13C-bicarbonate was also performed. Our SIP analyses indicate salt marsh crenarchaea are heterotrophic, double within 2–3 days and often compete with heterotrophic bacteria for the same organic substrates. A clone library of 13C-amplicons was screened to find matches to the 13C-TRFLP peaks, with seven members of the Miscellaneous Crenarchaeal Group and seven members from the Marine Group 1.a Crenarchaeota being discerned. Some of these crenarchaea displayed a preference for particular carbon sources, whereas others incorporated nearly every 13C-substrate provided. The data suggest salt marshes may be an excellent model system for studying crenarchaeal metabolic capabilities and can provide information on the competition between crenarchaea and other microbial groups to improve our understanding of microbial ecology.
Solar thermal polymerase chain reaction for smartphone-assisted molecular diagnostics
Authors: Jiang Li , Mancuso Matthew , Lu Zhengda , Akar Gunkut , Cesarman Ethel , Erickson David
Published: February 2014

Nucleic acid-based diagnostic techniques such as polymerase chain reaction (PCR) are used extensively in medical diagnostics due to their high sensitivity, specificity and quantification capability. In settings with limited infrastructure and unreliable electricity, however, access to such devices is often limited due to the highly specialized and energy-intensive nature of the thermal cycling process required for nucleic acid amplification. Here we integrate solar heating with microfluidics to eliminate thermal cycling power requirements as well as create a simple device infrastructure for PCR. Tests are completed in less than 30 min and power consumption is reduced to 80 mW, enabling a standard 5.5 Wh iPhone battery to provide 70 h of power to this system. Additionally, we demonstrate a complete sample-to-answer diagnostic strategy by analyzing human skin biopsies infected with Kaposi's Sarcoma herpesvirus (KSHV/HHV-8) through the combination of solar thermal PCR, HotSHOT DNA extraction and smartphone-based fluorescence detection. We believe that exploiting the ubiquity of solar thermal energy as demonstrated here could facilitate broad availability of nucleic acid-based diagnostics in resource-limited areas.
Ionic liquid-based green processes for energy production
Authors: Zhang Suojiang , Sun Jian , Zhang Xiaochun , Xin Jiayu , Miao Qingqing , Wang Jianji
Published: February 2014

We review ionic liquid-based processes in the renewable energy field, including CO2conversion, biomass conversion, solar energy and energy storage.
Tailored surfaces of perovskite oxide substrates for conducted growth of thin films
Authors: Sánchez Florencio , Ocal Carmen , Fontcuberta Josep
Published: February 2014

Overview of strategies for chemical termination control in perovskite single crystals and their use for the smart fabrication of functional nanostructures.
Delta-mu XANES reveals the electronic structure of the adsorption of propene on gold nanoparticles
Authors: Mijovilovich Ana
Published: February 2014

Experimental delta-mu spectra for the H oxidated and the propene co-fed Au nanoparticles were reproduced with XANES simulations with FEFF9. The results support that the propene has pi back-bonding to the Au with binding at defects or steps or in very small nanoparticles. Cationic, or even better, the neutrally charged Au nanoparticles, reproduce the experimental results of the propene co-fed catalyst found in the literature.
Chiral lanthanide complexes: coordination chemistry, spectroscopy, and catalysis
Authors: Bennett Stacey D. , Core Bryony A. , Blake Matthew P. , Pope Simon J. A. , Mountford Philip , Ward Benjamin D.
Published: February 2014

Luminescent lanthanide complexes bearing amido-bisoxazoline ligands are reported. They were studied using time-resolved luminescence spectroscopy, and were probed for their activity in hydroamination/cyclisation and ring-opening polymerisation catalysis.
Alkylaluminum dichloride–ether complexes which are fully soluble in hydrocarbons as catalysts for the synthesis of exo-olefin terminated polyisobutylene at room temperature
Authors: Vasilenko Irina V. , Shiman Dmitriy I. , Kostjuk Sergei V.
Published: February 2014

Highly reactive polyisobutylenes with a desirable low Mn were obtained with RAlCl2 × OiPr2 initiating systems with high monomer concentrations at room temperature.
Dissolution of wet wood biomass without heating
Authors: Abe Mitsuru , Yamada Tatsuhiko , Ohno Hiroyuki
Published: February 2014

Tetrabutylphosphonium hydroxide containing water made a wet wood disk swollen and extracted polysaccharides without heating.
Immobilization of urease on magnetic nanoparticles coated by polysiloxane layers bearing thiol- or thiol- and alkyl-functions
Authors: Pogorilyi R. P. , Melnyk I. V. , Zub Y. L. , Seisenbaeva G. A. , Kessler V. G.
Published: February 2014

An optimized strategy for production of a highly active magnetic formulation of urease has been elaborated via systematic studies of the enzyme immobilization on magnetite nanoparticles coated by functional siloxane layers.
Space–time interference analysis and suppression for airborne passive radar using transmissions of opportunity
Authors: Tan Danny Kai Pin , Lesturgie Marc , Sun Hongbo , Lu Yilong
Published: February 2014

This study presents the space–time snapshot models for the interfering passive signals received by the airborne passive radar which uses a ground‐based stationary non‐cooperative transmitter. The random range sidelobes couplings of the direct path and of the strong clutter signals into further range cells are major concerns in moving target detection performance. The least squares‐based adaptive interference cancellation technique is proposed to efficiently suppress the direct path, strong clutter and Doppler‐shifted strong clutter signals present at each antenna element prior to matched filter processing. In mitigating the interfering signals, their corresponding random range sidelobes will also be suppressed by the same amount. Ground‐based moving passive radar trials were conducted to validate and ascertain the effectiveness of the proposed adaptive interference cancellation algorithm.
Hydrothermal synthesis of uniform nanosized lithium‐rich cathode material Li0.94 [Li0.14Ni0.26Mn0.60]O2 for high power lithium‐ion batteries
Authors: Li Xueliang , Chen Li , He Wenxiang , Peng Fangfang , Xiao Zhenghui
Published: February 2014

A facile method of synthesising nanosized lithium‐rich layered material with uniform particle size by a one‐step hydrothermal approach has been developed. The effect of lithium ion concentration on hydrothermal products has been investigated. At low or high lithium ion concentration, products with poor layered characteristic were obtained. Under the optimum lithium ion concentration of 2.5 M, the obtained product has an Li0.94 [Li0.14Ni0.26Mn0.60]O2 stoichiometry with plate‐like morphology and a uniform particle size of ∼80 nm. The Brunauer‐Emmett‐Teller surface area measurement indicates that it possesses a surface area of 35.60 m2 g−1. The electrochemical tests show that the as‐prepared nanomaterial Li0.94 [Li0.14Ni0.26Mn0.60]O2 can acquire a high performance with an initial discharge capacity of 278 mAh g−1 at 30 mA g−1 and a corresponding capacity retention of 95% after 40 cycles. Moreover, it can even deliver 185 mAh g−1 at 1500 mA g−1, exhibiting excellent rate capability which makes it suitable for high power lithium‐ion batteries.
Recent performance of the SNS H− ion source and low-energy beam transport system
Authors: Stockli Martin P. , Ewald K. D. , Han B. X. , Murray S. N. , Pennisi T. R. , Piller C. , Santana M. , Tang J. , Welton R.
Published: February 2014

Recent measurements of the H− beam current show that SNS is injecting about 55 mA into the RFQ compared to ∼45 mA in 2010. Since 2010, the H− beam exiting the RFQ dropped from ∼40 mA to ∼34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.
Positive bias temperature instability in p-type metal-oxide-semiconductor devices with HfSiON/SiO2 gate dielectrics
Authors: Samanta Piyas , Huang Heng-Sheng , Chen Shuang-Yuan , Liu Chuan-Hsi , Cheng Li-Wei
Published: February 2014

We present a detailed investigation on positive-bias temperature stress (PBTS) induced degradation of nitrided hafnium silicate (HfSiON)/SiO2 gate stack in n+-poly crystalline silicon (polySi) gate p-type metal-oxide-semiconductor (pMOS) devices. The measurement results indicate that gate dielectric degradation is a composite effect of electron trapping in as-fabricated as well as newly generated neutral traps, resulting a significant amount of stress-induced leakage current and generation of surface states at the Si/SiO2 interface. Although, a significant amount of interface states are created during PBTS, the threshold voltage (VT) instability of the HfSiON based pMOS devices is primarily caused by electron trapping and detrapping. It is also shown that PBTS creates both acceptor- and donor-like interface traps via different depassivation mechanisms of the Si3 ≡ SiH bonds at the Si/SiO2 interface in pMOS devices. However, the number of donor-like interface traps ΔNitD is significantly greater than that of acceptor-like interface traps ΔNAit, resulting the PBTS induced net interface traps as donor-like.
Three-dimensional transition characterization in perpendicular and shingled recording
Authors: Lin E. E. , Wu X. , Liu F.
Published: February 2014

This paper introduces three-dimensional transition characterization on perpendicular and shingled magnetic recording. Writing and reading are synchronized to enable precise data capture. A modified read response model and a modified transition model were proposed and applied in transition analysis. Transitions recorded at various conditions were characterized.
Transient quantum coherent response to a partially coherent radiation field
Authors: Sadeq Zaheen S. , Brumer Paul
Published: February 2014

The response of an arbitrary closed quantum system to a partially coherent electric field is investigated, with a focus on the transient coherences in the system. As a model we examine, both perturbatively and numerically, the coherences induced in a three level V system. Both rapid turn-on and pulsed turn-on effects are investigated. The effect of a long and incoherent pulse is also considered, demonstrating that during the pulse the system shows a coherent response which reduces after the pulse is over. Both the pulsed scenario and the thermally broadened CW case approach a mixed state in the long time limit, with rates dictated by the adjacent level spacings and the coherence time of the light, and via a mechanism that is distinctly different from traditional decoherence. These two excitation scenarios are also explored for a minimal “toy” model of the electronic levels in pigment protein complex PC645 by both a collisionally broadened CW laser and by a noisy pulse, where unexpectedly long transient coherence times are observed and explained. The significance of environmentally induced decoherence is noted.
Light-induced hydrogen evolution from hydrogenated amorphous silicon: Hydrogen diffusion by formation of bond centered hydrogen
Authors: Tanimoto H. , Arai H. , Mizubayashi H. , Yamanaka M. , Sakata I.
Published: February 2014

The light-induced hydrogen evolution (LIHE) from amorphous (a-) Si:H by the order of at. % is observed during white light soaking (WLS) of 100–400 mW/cm2 at 350–500 K or ultra violet light soaking (UVLS) of 30–120 mW/cm2 at 305–320 K in a vacuum. The thermal desorption spectroscopy indicates that LIHE originated from bonded hydrogen takes place through the diffusion of light-induced mobile hydrogen (LIMH) with the activation energy of 0.5 eV. LIMH is assigned to bond centered hydrogen and the hydrogen diffusion process becomes prominent when LIMH can leave from a-Si:H such under light soaking in a vacuum above room temperature. For H2 in microvoids, the hydrogen evolution rate is governed by the surface barrier and its activation energy of 1.0 eV in dark decreases to 0.4 eV under WLS or UVLS.
Initial decomposition mechanism for the energy release from electronically excited energetic materials: FOX-7 (1,1-diamino-2,2-dinitroethene, C2H4N4O4)
Authors: Yuan Bing , Yu Zijun , Bernstein Elliot R.
Published: February 2014

Decomposition of the energetic material FOX-7 (1,1-diamino-2,2-dinitroethylene, C2H4N4O4) is investigated both theoretically and experimentally. The NO molecule is observed as an initial decomposition product subsequent to electronic excitation. The observed NO product is rotationally cold (<35 K) and vibrationally hot (2800 K). The initial decomposition mechanism is explored at the complete active space self-consistent field (CASSCF) level. Potential energy surface calculations at the CASSCF(12,8)/6-31G(d) level illustrate that conical intersections play an essential role in the decomposition mechanism. Electronically excited S2 FOX-7 can radiationlessly relax to lower electronic states through (S2/S1)CI and (S1/S0)CI conical intersections and undergo a nitro-nitrite isomerization to generate NO product on the S0 state. The theoretically predicted mechanism is consistent with the experimental results. As FOX-7 decomposes on the ground electronic state, thus, the vibrational energy of the NO product from FOX-7 is high. The observed rotational energy distribution for NO is consistent with the final transition state structure on the S0 state. Ground state FOX-7 decomposition agrees with previous work: the nitro-nitrite isomerization has the lowest average energy barrier, the C–NH2 bond cleavage is unlikely under the given excitation conditions, and HONO formation on the ground state surface is energy accessible but not the main process.
Effect of current density on magnetic properties of electrodeposited Fe-Ni films prepared in a citric-acid-based-bath
Authors: Yanai T. , Shimokawa T. , Watanabe Y. , Ohgai T. , Nakano M. , Suzuki K. , Fukunaga H.
Published: February 2014

In order to improve soft magnetic properties of electrodeposited Fe-Ni films prepared in a citric-acid-based bath, we investigated the effect of the current density on the grain size and the coercivity of Fe22Ni78 and Fe35Ni65 films. Consequently, we confirmed that increase in a current density reduces the coercivity and the grain size. This result suggests the exchange softening effect works effectively by the reduction in the grain size. We confirmed that the increase in the current density is effective to improve in soft magnetic properties of Fe-Ni films electrodeposited in the citric-acid-based bath.
Water dimer equilibrium constant calculation: A quantum formulation including metastable states
Authors: Leforestier Claude
Published: February 2014

We present a full quantum evaluation of the water second virial coefficient B(T) based on the Takahashi-Imada second order approximation. As the associated trace \documentclass[12pt]{minimal}\begin{document}$Tr[e^{-\beta {\bf H}_{AB}}-e^{-\beta {\bf H}_{AB}^o}]$\end{document}Tr[e−βHAB−e−βHABo] is performed in the coordinate representation, it does also include contribution from the whole continuum, i.e., resonances and collision pairs of monomers. This approach is compared to a Path Integral Monte Carlo evaluation of this coefficient by Schenter [J. Chem. Phys. 117, 6573 (2002)] for the TIP4P potential and shown to give extremely close results in the low temperature range (250–450 K) reported. Using a recent ab initio flexible potential for the water dimer, this new formulation leads to very good agreement with experimental values over the whole range of temperatures available. The virial coefficient is then used in the well known relation Kp(T) = −(B(T) − bM)/RT where the excluded volume bM is assimilated to the second virial coefficient of pure water monomer vapor and approximated from the inner repulsive part of the interaction potential. This definition, which renders bM temperature dependent, allows us to retrieve the 38 cm3 mol−1 value commonly used, at room temperature. The resulting values for Kp(T) are in agreement with available experimental data obtained from infrared absorption spectra of water vapor.
Efficient spin transfer torque in La2/3Sr1/3MnO3 nanostructures
Authors: Foerster Michael , Peña Luis , Vaz C. A. F. , Heinen Jan , Finizio Simone , Schulz Tomek , Bisig André , Büttner Felix , Eisebitt Stefan , Méchin Laurence , Hühn Sebastian , Moshnyaga Vasily , Kläui Mathias
Published: February 2014

We carry out low temperature magnetotransport measurements on nanostructured La2/3Sr1/3MnO3 wires to study the interaction between spin-polarized current and magnetization in this half metallic material. We selectively position domain walls by applying external fields. The domain wall resistance is found to be positive, in contrast to conventional 3d metals. The depinning field is reduced when current pulses are injected into the wire. By comparing measurements for both current polarities, we can disentangle heating and spin transfer torque effects. The determined spin transfer torque efficiency is of the order of 4 × 10−14 Tm2/A, which is significantly higher than in permalloy.
Electronic and magnetic properties of iron doped zirconia: Theory and experiment
Authors: Debernardi A. , Sangalli D. , Lamperti A. , Cianci E. , Lupo P. , Casoli F. , Albertini F. , Nasi L. , Ciprian R. , Torelli P.
Published: February 2014

We systematically investigated, both theoretically and experimentally, Zr1−xFexO2−y ranging from diluted (x ≈ 0.05) up to large (x ≈ 0.25) Fe concentration. By atomic layer deposition, we grew thin films of high-κ zirconia in cubic phase with Fe uniformly distributed in the film, as proven by time of flight secondary ion mass spectrometry and transmission electron microscopy measurements. Iron is in Fe3+ oxidation state suggesting the formation of oxygen vacancies with y concentration close to x/2. By ab-initio simulations, we studied the phase diagram relating the stability of monoclinic vs. tetragonal phase as a function of Fe doping and film thickness: the critical thickness at which the pure zirconia is stabilized in the tetragonal phase is estimated ranging from 2 to 6 nm according to film morphology. Preliminary results by X-ray magnetic circular dichroism and alternating gradient force magnetometry are discussed in comparison to ab initio data enlightening the role of oxygen vacancies in the magnetic properties of the system.
Quantitative relationship between contact stress and magnetic signal strength in perpendicular recording media
Authors: Liu Yuliang , Xiong Shaomin , Lou Jia , Bogy David B. , Zhang Guangyu
Published: February 2014

A series of nanoscratch experiments is conducted using constant loading scratch profiles to apply mechanical contact stress on perpendicular magnetic recording (PMR) media to cause its magnetic signal strength decay, which is characterized by the magnetic force microscope. The dependence of the magnetic signal strength on the applied normal load is quantitatively investigated. The results indicate that an increase of the applied normal load leads to a decrease of the magnetic signal strength. In addition, in order to obtain a more complete understanding of the results, a 3D finite element model is created to calculate the stress under different normal loads. Finally, the quantitative relationship between residual shear stress and magnetic signal strength is identified.
Tuning exchange bias in Fe/γ-Fe2O3 core-shell nanoparticles: Impacts of interface and surface spins
Authors: Khurshid Hafsa , Phan Manh-Huong , Mukherjee Pritish , Srikanth Hariharan
Published: February 2014

A comparative study has been performed of the exchange bias (EB) effect in Fe/γ-Fe2O3 core-shell nanoparticles with the same thickness of the γ-Fe2O3 shell (∼2 nm) and the diameter of the Fe core varying from 4 nm to 11 nm. Transmission electron microscopy (TEM) and high-resolution TEM confirmed the high quality of the core-shell nanostructures. A systematic analysis of magnetization versus magnetic field measurements under zero-field-cooled and field-cooled regimes using the Meiklejohn-Bean model and deconvoluting superparamagnetic and paramagnetic contribution to the total magnetic moment Langevin function shows that there exists a critical particle size (∼10 nm), above which the spins at the interface between Fe and γ-Fe2O3 contribute primarily to the EB, but below which the surface spin effect is dominant. Our finding yields deeper insight into the collective contributions of interface and surface spins to the EB in core-shell nanoparticle systems, knowledge of which is the key to manipulating EB in magnetic nanostructures for spintronics applications.
Meta-aromatic polyurea with high dipole moment and dipole density for energy storage capacitors
Authors: Wu Shan , Lin Minren , Burlingame Quinn , Zhang Q. M.
Published: February 2014

A dielectric polymer, i.e., meta-aromatic polyurea(meta-PU) was developed and investigated for high energy density, low loss energy storage capacitors. Modifications to the molecular structure can tune the dipolar density and dipole moment in the polyurea systems to improve the dielectric properties. Meta-PU was synthesized via a green synthetic route with a higher volume dipolar density than the aromatic polyurea previously reported. The meta-PU has an enhanced dielectric constant, higher energy density, and a high electrical breakdown. A high storage electrical energy density of 13 J/cm3 and energy storage efficiency of 91% can be achieved at 670 MV/electric field.
Second harmonic generation from direct band gap quantum dots pumped by femtosecond laser pulses
Authors: Liu Liwei , Wang Yue , Hu Siyi , Ren Yu , Huang Chen
Published: February 2014

We report on nonlinear optical experiments performed on Cu2S quantum dots (QDs) pumped by femtosecond laser pulses. We conduct a theoretical simulation and experiments to determine their second harmonic generation characteristics. Furthermore, we demonstrate that the QDs have a second harmonic generation conversion efficiency of up to 76%. Our studies suggest that these Cu2S QDs can be used for solar cells, bioimaging, biosensing, and electric detection.
Sign change of exchange bias in [Pt/Co]3/IrMn multilayer
Authors: Yoon Seungha , Kwon Joonhyun , Cho B. K.
Published: February 2014

The properties of exchange bias in a multilayer of [Pt(1.0 nm)/Co(1.0 nm)]2/Pt(tPt nm)/Co(1.0 nm)/ IrMn(12.0 nm) were investigated with a variation of Pt layer thickness, tPt. For tPt ≤ 1.6 nm, it was typically observed that Co layers were ferromagnetically coupled while IrMn layer exhibited negative exchange bias. With increasing Pt thickness, antiferromagnetic (AF) interlayer coupling strength increased and caused AF spin configuration between the Co layers. With further increasing of Pt thickness (tPt = 2.5 nm), the exchange bias between Co and IrMn layers was changed from negative to positive. Therefore, a large enhancement of AF interlayer coupling induced the sign change of exchange bias from negative to positive and resulted in a drastic change of switching behavior in a magnetization reversal. Both extraordinary Hall-effect and magnetoresistance were measured to verify the exchange bias direction and spin configurations upon magnetization reversal.
Nanosecond, repetitively pulsed microdischarge vacuum ultraviolet source
Authors: Stephens J. , Fierro A. , Walls B. , Dickens J. , Neuber A.
Published: February 2014

A microdischarge is driven by short pulses (80 ns FWHM) with peak current levels up to 80 A, with a repetition frequency of 1 MHz (1 pulse/μs) allowing for ∼550 W input power. Experiments in pure argon (Ar2*, 127 nm) and argon-hydrogen (Lyman-α, 121.6 nm) were conducted. Using short pulses, the argon excimer emission was not observed. Alternatively, Ar-H2 operated at both higher power and efficiency (0.63%) whenever pulsed. Using Ar-H2, the experiments result in an average generated vacuum ultraviolet power just above 3.4 W with a peak power of 42.8 W, entirely at Lyman-α.
Stalled transcription complexes promote DNA repair at a distance
Authors: Haines Nia M. , Kim Young-In T. , Smith Abigail J. , Savery Nigel J.
Published: February 2014

Significance

DNA repair efficiency varies across the genome. This is due, in part, to repair pathways that are linked to transcription. When RNA polymerase stalls at a DNA lesion, repair proteins are recruited in a process called transcription-coupled nucleotide excision repair (TCR). We have examined the substrate requirements for TCR using a system in which transcription stalling is disconnected from the search for the DNA lesion. We show that stalled or paused transcription complexes initiate a damage-detection process that promotes strand-specific repair of lesions over a considerable distance. Our findings help to explain the mechanism by which the repair of active genes is accelerated and suggest that some transcription pause sites may target repair activity to specific regions of the genome.