bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of all‐conjugated poly(3‐hexylthiophene)‐block‐ poly(3‐(4′‐(3″,7″‐dimethyloctyloxy)‐3′‐pyridinyl)thiophene) and its blend for photovoltaic applications
Authors: Lai Yi‐Cang , Ohshimizu Kaoru , Takahashi Ayumi , Hsu Jung‐Ching , Higashihara Tomoya , Ueda Mitsuru , Chen Wen‐Chang 
Published: April 2011

AbstractNew all‐conjugated block copolythiophene, poly(3‐hexylthiophene)‐block‐poly(3‐(4′‐(3″,7″‐dimethyloctyloxy)‐3′‐pyridinyl)thiophene) (P3HT‐b‐P3PyT) was successfully prepared by Grignard metathesis polymerization. The supramolecular interaction between [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) and P3PyT was proposed to control the aggregated size of PCBM and long‐term thermal stability of the photovoltaic cell, as evidenced by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and optical microscopy. The effect of different solvents on the electronic and optoelectronic properties was studied, including chloroform (CL), dichlorobenzene (DCB), and mixed solvent of CL/DCB. The optimized bulk heterojunction solar cell devices using the P3HT‐b‐P3PyT/PCBM blend showed a power conversion efficiency of 2.12%, comparable to that of P3HT/PCBM device despite the fact that former had a lower crystallinity or absorption coefficient. Furthermore, P3HT‐b‐P3PyT could be also used as a surfactant to enhance the long‐term thermal stability of P3HT/PCBM‐based solar cells by limiting the aggregated size of PCBM. This study represents a new supramolecular approach to design all‐conjugated block copolymers for high‐performance photovoltaic devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Adsorption of Sn on the Ge(111)‐(3 × 3) surface studied by ab initio density functional theory
Authors: Özkaya Sibel , Çakmak Mehmet , Alkan Bora 
Published: April 2011

AbstractWe present detailed ab initio density functional calculations of equilibrium atomic geometry, electronic states, and chemical bonding for the adsorption of the elemental Sn atoms on the Ge(111)‐(3 × 3) surface. Three different possible models: (i) IDA model (inequivalent‐two‐down Sn atoms), (ii) 1U2D model (one‐up Sn atom, two‐equivalent‐down Sn atoms), and (iii) 2U1D model (two‐up Sn atoms, one‐down Sn atom) have been considered. From these three models, it has been found that the IDA and 1U2D models are energetically favorable than the third model. The energy difference between the IDA and 1U2D model is negligibly small. For the IDA model, the height difference between two down atoms in IDA model is significant. A total of three surface states originating from the Sn adatoms is determined. The results are in good agreement with the recent high‐resolution photoemission and scanning tunneling microscopy experiments.
Evaluation of GaN by photoluminescence measurement
Authors: Reshchikov Michael A. 
Published: April 2011

AbstractComparison of the room‐temperature photoluminescence (PL) spectra from a high‐quality freestanding GaN template and an average‐quality GaN layer on sapphire substrate shows that the width of the exciton band in the former may be twice larger than that in the latter. The surprising fact can be explained by a wide depletion region and large diffusion length of photogenerated carriers in high‐quality GaN templates. Photogenerated electrons and holes in this material recombine at larger distance from the surface, and the exciton emission from this depth experiences stronger absorption that causes distortion of the near‐bandedge PL and its broadening. We also explain why the intensity of the exciton emission may be low and the defect‐related PL may dominate in the room‐temperature PL spectrum of high‐quality samples. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Surface properties of AlxGa1‐xN/GaN heterostructures treated by fluorine plasma: an XPS study
Authors: Huang Sen , Chen Hongwei , Chen Kevin J. 
Published: April 2011

AbstractThe variations in surface potential and the Schottky barrier height ΦB in fluorine‐plasma‐treated AlxGa1‐xN/GaN heterotructures are systematically studied by x‐ray photoelectron spectroscopy (XPS), giving insights into the mechanisms underlying the strong threshold voltage shift in AlxGa1‐xN/GaN HEMTs by the F plasma treatment technology. It is found that the treatment resulted in a fluorinated surface containing masses of AlF3, with the surface potential of Al0.25Ga0.75N/GaN heterostructure increased by ∼0.38 eV during the first 60 seconds of the treatment. Annealing at 400 °C in N2 ambient for 10 minutes does not affect the surface potential, but results in quick reduction of AlF3, consistent with the relative poor thermal stability of AlF3 reported in literature. ΦB between Ni and F‐plasma‐treated Al0.25Ga0.75N surface was extrapolated from the shift in Ga 2p3/2 core‐level and exhibits a small increase of 0.20 eV. The enhanced ΦB is much smaller than the positive shift in Vth observed from HEMTs fabricated with the same treatment conditions, suggesting that the primary factor responsible for the conversion from depletion‐mode to enhancement‐mode AlxGa1‐xN/GaN by F plasma treatment is not the surface modifications, but rather the negative fixed charges carried by F ions in AlxGa1‐xN/GaN heterostructures. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semi‐polar InN(10$ \bar 1 $3) dominant growth on GaAs(110) substrate by mixing hydrogen in carrier gas
Authors: Cho H. C. , Suematsu M. , Murakami H. , Kumagai Y. , Tob R. , Koukitu A. 
Published: April 2011

AbstractThe growth of semi‐polar InN(10$ \bar 1 $3) on a GaAs(110) substrate by metal organic vapor phase epitaxy (MOVPE) was investigated. It was confirmed that the semi‐polar InN(10$ \bar 1 $3) plane was dominantly grown by mixing 0.4% hydrogen in nitrogen carrier gas, whereas a ‐plane InN was mixed without hydrogen gas. An ω‐mode X‐ray rocking curve of the InN(10$ \bar 1 $3) plane revealed that the InN(10$ \bar 1 $3) crystals were tilted approximately 1.1∼1.4° in the direction of the GaAs[111] due to the structural difference between InN(10$ \bar 1 $3) and GaAs(110). Although the as‐grown InN was twin crystal, however, the integrated intensity of smaller peak was less than 1% in related to that of the other peak. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis as‐randomized and the problem of non‐adherence: An example from the veterans affairs randomized trial of coronary artery bypass surgery
Authors: Peduzzi Peter , Wittes Janet , Detre Katherine , Holford Theodore 
Published: April 2011

AbstractIn most randomized clinical trials not all patients adhere to the therapy to which they were randomly assigned. Instead, they may receive the therapy assigned to another treatment group, or a therapy different from any prescribed in the protocol. When non‐adherence occurs, problems occur with the analysis comparing the treatments under study. Rigorous statistical principles require attributing outcome events to the original random treatment assignment (‘intent‐to‐treat’ analysis). Using data from the Veterans Administration Cooperative Study of Coronary Artery Bypass Surgery, we report the intent‐to‐treat analysis and apply four other methods of analysis for analysing non‐adherers: 1. exclude non‐adherers from analysis; 2. transfer them to the alternative treatment group at the time of randomization; 3. censor them at the time of treatment change, and 4. transfer them to the alternative treatment group at the time of treatment change. Inherent problems and biases of these four other methods are discussed.
Methods for assessing difference between groups in change when initial measurement is subject to intra‐individual variation
Authors: Chambless Lloyd E. , Roeback John R. 
Published: April 2011

AbstractStatistical analysis of difference between groups in change for some variable, adjusting for initial value, is complicated by the presence of intra‐individual variation in that variable. We estimate here the asymptotic bais that results from calculating the adjusted between‐group difference by ordinary least squares (OLS) from observed data. We also present explicit formulae that use the OLS estimates, the difference between treatment groups in mean initial values, and a measure of the intra‐individual variation to compute a corrected estimator and its variance. Alternatively, we can use OLS on transformed data to obtain unbiased estimates, in which we replace initial observed values by conditional Stein estimates of true values. We illustrate the results with data from an observational study and a clinical trial.
Design effects for binary regression models fitted to dependent data
Authors: Neuhaus John M. , Segal Mark R. 
Published: April 2011

AbstractDependent data, such as arise with cluster sampling, typically yield variances of parameter estimates which are larger than would be provided by a simple random sample of the same size. This variance inflation factor is called the design effect of the estimator. Design effects have been derived for cluster sampling designs using simple estimators such as means and proportions, and also for linear regression coefficient estimators. In this paper, we show that a method to derive design effects for linear regression estimators extends to generalized linear models for binary responses. In particular, some simple expressions for design effects in the linear regression model provide accurate approximations for binary regression models such as those based on the logistic, probit and complementary log—log links. We corroborate our findings with two examples and some simulation studies.
Modeling of Mechanical Characteristics in Hot Deformation of 4130 Steel
Authors: Sajadifar S.V. , ketabchi M. , Nourani M. 
Published: April 2011

AbstractIn this investigation, hot compression tests were performed at 900 °C − 1100 °C and strain rate of 0.001 − 0.1 s−1 to study hot deformation behavior and flow stress model of 4130 steel. Based on the classical stress–dislocation relations and the kinematics of the dynamic recrystallization, the flow stress constitutive equations of the work hardening‐dynamical recovery period and dynamical recrystallization period were established for 4130 steel, respectively. The validity of the model was demonstrated by comparing the experimental data with the numerical results. The agreement of this comparison is quite reasonable.
A model and scoring system to predict outcome of intrauterine pregnancies of uncertain viability
Authors: Bottomley C. , Van Belle V. , Pexsters A. , Papageorghiou A. T. , Mukri F. , Kirk E. , Van Huffel S. , Timmerman D. , Bourne T. 
Published: April 2011

AbstractObjectivesTo define the incidence and outcome of intrauterine pregnancy of uncertain viability (PUV) and to develop and assess the performance of a model and a scoring system to predict ongoing viability.MethodsOf 1881 consecutive women undergoing transvaginal ultrasonography, a cohort of 493 women with an empty gestational sac < 20 mm in mean diameter, gestational sac < 25 mm in mean diameter and containing yolk sac only or an embryonic pole < 6 mm in maximum length and without visible heart activity were followed until the end of the first trimester. Women with multiple pregnancies or who underwent termination of pregnancy were excluded. Outcome measures were pregnancy viability at initial 7–14‐day follow‐up and first‐trimester viability at 11–14 weeks. The data were split randomly into two sets (two‐thirds and one‐third, respectively) in order to first develop and then test a mathematical model and a ‘simple’ model in the prediction of viability at each outcome point, based on maternal demographics, ultrasound features and symptoms. The performance of each system was assessed by receiver–operating characteristics (ROC) curve analysis and calibration plots on a test dataset.ResultsThe incidence of PUV in this population was 29.2% (549/1881). Of the 493 pregnancies with initial (7–14 days) follow‐up available, 307 (62.3%) were viable at this time and of the 444 pregnancies with follow‐up at the end of the first trimester, 225 (50.7%) were still viable. Initial (7–14‐day) viability was predicted by the model with an area under the ROC curve (AUC) of 0.837 (95% CI, 0.791–0.884) in the training dataset and 0.821 (95% CI, 0.756–0.885) in the test dataset. First‐trimester (11–14‐week) viability was predicted by the model with an AUC of 0.788 (95% CI, 0.734–0.842) in the training dataset and 0.774 (95% CI, 0.701–0.848) in the test dataset. The scoring system performed slightly worse than did the model, but had the advantage of being easily applicable.ConclusionsWhen early pregnancy viability cannot be established immediately with ultrasound, use of either a logistic regression model or a scoring system allows an individualized prediction of first‐trimester outcome. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Mid-Holocene coastal hydrology and salinity changes in the east Taihu area of the lower Yangtze wetlands, China
Authors: Zong Yongqiang , Innes James B. , Wang Zhanghua , Chen Zhongyuan 
Published: April 2011

AbstractDuring the mid-Holocene the eastern Taihu area, on China's Yangtze delta plain, was populated by advanced late Neolithic cultures supported by intensive domesticated rice cultivation. This agricultural system collapsed around 4200 cal yr BP, with severe population decline, the end of the Liangzhu culture, and about half a millennium of very low-scale human activity in the area before the re-establishment of agricultural production. Microfossil analyses from six sedimentary sequences, supported by AMS 14C dating, has allowed reconstruction of mid-Holocene hydrological conditions and salinity changes which would have had a major influence on agricultural viability and cultural history in the coastal wetlands. These data, allied to existing stratigraphic and sea-level records, show that chenier ridges that developed after ca. 7000 cal yr BP in the east of the area sheltered it from marine inundation and although still connected to the sea through tidal creeks, low-salinity conditions persisted throughout the Neolithic period. There is no evidence that marine flooding caused the collapse of Liangzhu culture. Marine influence was stable and evolved slowly. Social and cultural causes may also have been important, but if environmental change triggered the collapse of Neolithic agricultural society here, other natural forces must be sought to explain this event.
James Theobald's ‘Missing’ MS: History of the Society of Arts and his ‘Chronological Register’ of ‘the Present Age’
Authors: Allan D. G. C. , Appleby J. H. 
Published: April 2011

The discovery in the Society's library of James Theobald's manuscript history of the foundation of the Society of Arts is a satisfying conclusion to a search which has been pursued since the early years of the twentieth century. This search had been stimulated by a statement in a rare eighteenth-century tract entitled: A Concise Account of the Rise, Progress, and Present State of the Society For the Encouragement of Arts, Manufactures and Commerce Instituted at London, Anno. MDCCLIV. Compiled from the Original Papers of the first Promoters of the plan; and from other authentic records. By a Member of the said Society. London: Printed for the AUTHOR, and sold by S Hooper, at Caesar's Head, the corner of the New Church in the Strand. MDCCLXIII. The author, who has been identified as Thomas Mortimer, wrote in his introduction:Several particulars relative to the origin of this Society having been lost to the public for many years, it may not be improper to mention, least the authenticity of the following narrative should be disputed, that the substance of it was drawn up by the late James Theobald, Esq; one of the first Vice Presidents of the Society, from a verbal relation given him by Mr Shipley; and that the same gentleman afterwards presented a copy of that relation to the Antiquarian Society.
Quem Aspicientes Viverent: Symbolism in the Early Medieval Church Door and its Ironwork
Authors: Bradley S. A. J. 
Published: April 2011

SummarySymbolic perception of the church door in early English exegetical writings and in medieval liturgical practice is illustrated and discussed as the wider context of a proposal that the arched iron strip at the top of the twelfth-century church door at Stillingfleet, North Yorkshire, represents the rainbow of Noah's Flood, perceived as a reminder ofjudgement past and of judgement still to come, and as a symbol of the covenant between God and humanity. The possibility is considered that on other surviving early medieval church-doors too, the rainbow shape, even if primarily functional or dictated by the shape of the door-opening, and notwithstanding the absence of other figural imagery, may have been recognized as an emblem of the covenant, basis of all church-sanctioned contracts, aptly dislayed on the threshold—where various liturgical or other formal actions had their setting—of the sacred spaces of the domus dei.
How to Win at Tournaments: the Technique of Chivalric Combat
Authors: Anglo Sydney 
Published: April 2011

SummaryAlthough it has generally been maintained that chivalric combat depended solely on strength and endurance, there is ample evidence that skill, dexterity, speed and control were also required. This paper attempts to reconstruct the techniques used in foot combats, tourneying on horseback and jousting (especially tilting)—in England, France, Italy and the Iberian Peninsula—on the basis of narratives and technical treatises, concerning sword and lance play, written between the late fourteenth and early seventeenth centuries.
Stoneleigh After The Grand Tour
Authors: Gomme Andor 
Published: April 2011

SummaryExamination of the account books and other papers, now chiefly deposited in the Record Office of the Shakespeare Birthplace Trust, Stratford-upon-Avon, has enabled a chronology to be prepared of the long-drawn-out construction and decoration of the eighteenth-century west range of Stoneleigh Abbey. The contributions of the four architects principally involved—Francis and William Smith, William Hiorn and Timothy Lightoler—have been assessed, together with those of the more prominent craftsmen. In particular, the process by which the hall (or saloon) achieved its final form in 1763-5 is explored and suggestions made about the authorship of its remarkable stucco decoration.
The Town and Castle of Conwy: Preservation and Interpretation
Authors: Taylor A. J. 
Published: April 2011

This note summarizes and expands one of the short papers communicated to the Society on 23rd February 1995 under the title of ‘New Thoughts on Some Castles in Wales’.The paper's purpose was twofold. First, it sought to present, through a series of ‘before and after’ photographs (figs. 1-8), an up-to-date picture of the transformation effected at Conwy in the course of the last forty years, not only by the careful and conservative repair of the fabric of both components of the monument, i.e. town walls as well as castle, but also by the systematic clearance wherever possible of every kind of built disfigurement from the forefront of the medieval enceinte, so as to reveal and display anew the whole circuit of towers and curtains in an ambience worthy of Britain's most outstanding example of medieval town fortification. Closely related to the process of gradually re-establishing awareness of the monument's unity, with the walls receiving the same respect, in financial as in other terms, as the castle and the work of repair proceeding simultaneously on both, was the defeat, likewise a long and complex process, of the Welsh Office's proposal effectively to destroy the natural setting and amenity of the whole southward aspect of castle and walls alike by driving a dual-carriageway ‘express-way’ through the Gyffin valley (brazenly promoted as the Minister's ‘preferred route’) and erecting a monster new suspension bridge whose ‘goalposts’ would have overtopped even the turrets of the castle towers. The abandonment of this disastrous plan, in favour of the submerged tube tunnel under the river opened by H.M. the Queen in October 1991, was of incalculable benefit in preserving Conwy's unique character into the future. As such, it has its proper place in the present record (figs. 9-12).
An Early to Middle Saxon Settlement at Quarrington, Lincolnshire
Authors: Taylor Gary , Allen Carol , Bayley Justine , Cowgill Jane , Fryer Val , Palmer Carol , Precious Barbara , Rackham James , Roper Tessa , Young Jane 
Published: April 2011

Excavations undertaken at Quarrington, near Sleaford, Lincolnshire, revealed part of an Early and Middle Saxon settlement with associated fields or enclosures. Several timber buildings were identified, both round and rectangular, and there was evidence of ferrous and non-ferrous metalworking at the site. Finds included a large and regionally significant pottery assemblage, showing that Quarrington had an extensive trading network and obtained pottery from Lincolnshire and Leicestershire in the Early Saxon period. Pottery from the Northamptonshire area dominated the assemblage in the Middle Saxon period, with a smaller component from Lincolnshire and a limited quantity from Ipswich. Spatial variations in the Saxon ceramic assemblage suggest that the focus of settlement shifted towards the west or north west in the Middle Saxon period.Few rural sites of Early and Middle Saxon date have produced sufficient faunal material to permit an analysis of changes during the fifth to eighth centuries until now; the large bone assemblage from Quarrington indicates changes in diet and the husbandry of domestic animals through time, with sheep becoming more important as pig diminished. Alterations to the slaughter profiles of cattle and sheep were also evident and may indicate changes from subsistence to surplus production. An apparently isolated Neolithic cremation and a post-medieval stone building were also revealed.
Optimal culling strategy in relation to biological and economic efficiency and annualized net revenue in the Japanese Black cow–calf production system
Authors: OISHI K. , IBI T. , KAHI A. K. , HIROOKA H. 
Published: April 2011

SUMMARYThe objective of the present study was to determine the optimal culling strategy in relation to biological and economic efficiency (BE and EE, respectively) and annualized net revenue (AN) in the Japanese Black cow–calf production system with special reference to the beef quality of culled cows. The herd model focused on two ways of mating: one-mating trial system (ONE) and continuous-mating trial system (CON). ONE assumed that heifers that fail to conceive are culled and cows that fail to conceive are culled at weaning of their calves, while CON assumed that mating continues until all females theoretically conceive. Least square means of carcass data of Japanese Black cows collected from a cooperative farm in Japan were used to estimate the carcass price of a cow by parity and Beef Marbling Standard (BMS) number. The simulation, assuming the current production situation in Japan, indicated that sales of culled cows accounted for 0·10–0·20 of total sales and was an important element in total production. Comparisons between ONE and CON showed that production efficiency in the current situation is higher in CON. The BE, EE and AN were higher in CON than in ONE. The two economic indicators were less sensitive to changes in annual discount rate but highly sensitive to changes in female calf price and BMS number of cows, indicating the importance of considering fluctuations in calf price and potential quality of culled cows’ carcasses when estimating the economically optimal parity of culling. The three indicators derived different optimal solutions even in the same mating trial systems, stressing the importance of choice of production indicators when determining the culling strategy and evaluating animal production.