bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporation of a phospholipid precursor into the subcellular organelles of 9‐methylpteroylglutamic acid‐treated rat embryos
Authors: Chepenik Kenneth P. , Waite B. Moseley
Published: September 2005

Pregnant Long‐Evans rats were fed a synthetic diet lacking folic acid and containing 9‐methylpteroylglutamic acid on the llth day of gestation and then fed a complete diet beginning on the 14th day. Treated and untreated pregnant rats injected with 10 μCi of [14C] ethanolamine on the 12th or 14th day of gestation were killed on the 14th, 15th, or 16th day. The total radioactivity and radioactivities of phosphatidylethanolamine (PE), phosphatidylcholine (PC), and lysophosphatidylethanolamine (LPE) were determined in chloroform extracts of homogenates and subcellular fractions prepared from whole emhryos on the designated days of gestation. The specific radioactivity of phospholipids extracted from the lysosomal‐rich fraction of treated embryos was twice that of controls but the phospholipid‐specific radioactivity of the low‐speed fraction from treated embryos was one‐half of that of controls on the 14th day. The relative distribution of radioactivity in PE and PC extracted from subcellular organelles of either treated or untreated embryos suggested a precursor‐product relation. The conversion of radiolabeled PE to PC seemed to occur faster in almost all subcellular fractions of the treated embryos and did not occur in the same temporal order from fraction to fraction as was found for untreated embryos. These data were interpreted to mean that the teratogen (1) stimulated lysosomal synthesis and depressed nuclear synthesis, (2) perturbed intraembryonic transmethylation of PE to lecithin, perhaps shifting the embryo to a greater dependence on placental metabolism or transport, and (3) disturbed the chemical composition of various intraernbryonic subcellular membranes.
The influence of single or fractionated doses of 5‐fluoro‐2′‐deoxycytidine teratogenicity in mice
Authors: Sasaki Hiroshi , Ohmori Kazuo
Published: September 2005

5‐fluoro‐2'‐deoxycytidine (FCdR) was administered ip to pregnant
ICR‐JCL mice on days 7 to 12 of pregnancy either at a single dose of 1.5 mg/kg or
five fractionated doses of the same total amount at 3‐h intervals. The fraction‐
ated injections resulted in much stronger teratogenic effects than single injection
on days 9, 10, and 11 of pregnancy. Embryocidal effects of fractionated injections
were more severe than single injection on days 9 and 10 of pregnancy. The mal‐
formation frequency produced by fractionated injection was at least equivalent to
single doses of 7.5 mg/kg when the drug was given on day 9 of pregnancy.
Growth discrepancy in twins in the first trimester of pregnancy
Authors: Salomon L. J. , Cavicchioni O. , Bernard J. P. , Duyme M. , Ville Y.
Published: September 2005

Objective

The prevalence and significance of intertwin growth discrepancy in the first trimester of pregnancy are controversial. The aim of this study was to refine the incidence and outcome of this discrepancy in relation to dating of the pregnancy and other biometric parameters.

Methods

This prospective study of twin pregnancies initially evaluated at 11–14 weeks' gestation was conducted between 2001 and 2004. Differences in crown–rump length (CRL) and estimated gestational age (GA) were calculated for each twin pair and their distribution was analyzed according to chorionicity and mode of conception (spontaneous or following assisted reproductive technologies). CRL‐based GA and actual GA were compared. Other biometric parameters were also compared for each twin pair. The distribution of discrepancies was analyzed according to pregnancy outcome.

Results

A total of 182 twin pregnancies was included. The mean ± SD discrepancy in CRL was 3.4 ± 3.18 mm or 5.1 ± 4.69% and the 95th centile was 9.8 mm or 14.3%. There was no influence of chorionicity (P = 0.44), mode of conception (P = 0.18) and no relation with outcome (P = 0.54). In conceptions resulting from assisted technology, the measured CRL of the smaller twin was closer to the actual GA. Cephalic and abdominal biometric measurements were significantly greater in the twin with the smaller CRL (P < 0.05). The two cases with a discrepancy >15 mm were affected by trisomy 18 and triploidy, respectively.

Conclusions

CRL discrepancy in twin pregnancies in the first trimester is a frequent finding. Discrepancy >95th centile indicates major growth delay of one twin, which could indicate the presence of aneuploidy. For milder degrees of discordance the CRL of the smaller fetus is a more accurate estimate of the actual GA. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
praise and piety: niya¯yišns and yašts in the history of zoroastrian praxis
Authors: choksy jamsheed k. , kotwal firoze m.
Published: September 2005

scripture has ritual uses aimed at giving religion meaning in daily life. in zoroastrianism, the niya¯yišns, ‘invocations of praise’, and the yašts, ‘devotional poems’ have played fundamental roles in connecting doctrine and theology to praxis and conviction whereby faith and rites have been transmitted and augmented across many generations. this article discusses some of the contents and traditions of each niya¯yišn and yašt plus the functions those religious texts have fulfilled and continue to serve for zoroastrians from ancient through modern times.
the emergence of modern ‘sikh theology’: reassessing the passage of ideas from trumpp to bha¯i¯ vi¯r singh
Authors: mandair arvind-pal s.
Published: September 2005

steering between opposing explanations of religion as either sui generis or sociological construction, this paper argues for an alternative way of conceptualizing the phenomenon called ‘sikh theology’. normally attributed to the interior religious experience of the founder of sikhism, ‘sikh theology’, it will be argued, can more usefully be envisaged as the product of a discursive regime, a regime of colonial translation, which effectively demarcated the conceptual framework of modern sikhism. this regime of translation contains an ideology about religion that made translators such as ernest trumpp imagine the work of translation as providing a remedy for a scripture perceived as lacking conceptual coherence, or in the case of trumpp's non-sikh protagonist m.a. macauliffe, as based on a ‘dialogical interaction’ with sikh native informants. the paper's main focus is to show how key theological concepts passed from trumpp to macauliffe, and were inadvertently imbibed by writers of the exegetical commentaries on scripture such as bha¯i¯ vi¯r singh, even as they were contesting trumpp's odium theologicum.
rejection or acceptance: finding reasons for the late qing magistrate's comments on land and debt petitions
Authors: liang linxia
Published: September 2005

many scholars accept that the magistrate under the qing (1644–1911) dealt with land and debt disputes with great discretion. through the investigation of first-hand court records of magistrates' reasons for accepting or rejecting land and debt petitions, this article demonstrates for the first time that the assumption and myth that the magistrate either returned petitions to mediators for settlement or dealt with them in a solomonic fashion does not hold water. the magistrate rejected or accepted petitions on the merits of individual cases in accordance with qing law. it shows that litigation on private matters in the qing was rationally administered even at this stage.
Acquiring the English adjective lexicon: relationships with input properties and adjectival semantic typology
Authors: BLACKWELL ALEKA AKOYUNOGLOU
Published: September 2005

Properties of the input, such as raw frequency and syntactic diversity, have been shown to play a role, to different extents, in the acquisition of nouns and verbs. This study investigated the relationship between three properties of the input (input frequency, syntactic diversity, and variety in noun-type co-occurrence) and age of acquisition of English adjectives. In addition, this study explored the relationship between adjectival semantic typology and order of acquisition. The data are 7262 child utterances and 6318 maternal utterances containing one of 272 adjective in the language samples of two children, Sarah and Adam, from age 2;3 to 5;0 (Brown, 1973) available in CHILDES (MacWhinney, 2000). Statistical analyses revealed that all three properties of the input were significantly correlated with age of acquisition, but variety in noun-type co-occurrence was not a significant predictor once input frequency and syntactic diversity were taken into account. Semantic analyses revealed that the distribution of adjective types and tokens differed between the children and the mothers (to an extent) when the data were examined in terms of adjectival semantic types. The results suggest that both properties of the input and the semantic properties of the English adjective class play a role in its acquisition.
When opportunity knocks twice: two-year-olds' repetition of sentence subjects
Authors: VALIAN VIRGINIA , AUBRY STEPHANIE
Published: September 2005

Why are young children's utterances short? This elicited imitation study used a new task – double imitation – to investigate the factors that contribute to children's failure to lexicalize sentence subjects. Two-year-olds heard a triad of sentences singly and attempted to imitate each; they then again heard the same triad singly and again attempted to imitate each. Comparisons between the two attempts showed that children's second passes were more accurate than their first. In addition, independent of sentence length, children increased their inclusion of pronominal and expletive but not lexical subjects. Children included verbs more often from sentences with pronominal than lexical subjects, suggesting a trade-off. Children included subjects more often in short sentences than long ones, and increased subject inclusion only in short sentences. The results suggest that children's language production is similar to adults': a complex interaction of syntactic knowledge, limited cognitive resources, communicative goals, and conversational structure.
Richard Scheringer, the KPD and the Politics of Class and Nation in Germany, 1922–1969
Authors: BROWN TIMOTHY S.
Published: September 2005

This article examines the life and times of Richard Scheringer, an army officer and supporter of Adolf Hitler who became famous during the early 1930s for his high-profile conversion to communism. Known in the closing years of the Weimar Republic as a point-man for Communist efforts to win support from the radical right, Scheringer survived the Third Reich to become a leading figure in the postwar Communist Party. His well-documented but little-studied career, bridging critical caesurae of modern Germany history, highlights the unique political constellation of the interwar period, demonstrating fundamental continuities in the relationship of German communism to the nation before and after 1945.
The Making of the CAP: Towards a Historical Analysis of the EU’s First Major Policy
Authors: LUDLOW N. PIERS
Published: September 2005

This article seeks to explain the emergence of the CAP between 1958 and 1968. It draws attention to four particular political factors that made the policy’s birth possible, despite the vagueness of the Treaty of Rome commitment to an agricultural policy and the unpromising precedents of earlier attempts to integrate Europe’s agriculture. These were the strength of the coalition pushing for the CAP’s emergence (primarily composed of France, the Netherlands and the European Commission), the weakness and inconsistencies of their opponents (Germany and Italy), the favourable international context, and the incremental nature of the policy’s development. The article further argues that the complexity of the bargaining over the farm support policy, and the manner in which CAP discussions often became entwined with other seemingly unrelated aspects of EEC decision-making, illustrate how even the early Community of the 1960s was sufficiently complex to require a radical change of approach from those who wish to study its historical development.
After the Holocaust: The History of Jewish Life in West Germany
Authors: MENG MICHAEL L.
Published: September 2005

In July 1945, Rabbi Leo Baeck remarked that the Third Reich had destroyed the historical basis of German Jewry. ‘The history of Jews in Germany has found its end. It is impossible for it to come back. The chasm is too great’. Heinz Galinski, a survivor of Auschwitz who led West Berlin’s Jewish community until his death in 1992, could not have disagreed more strongly. ‘I have always held the view’, he observed, ‘that the Wannsee Conference cannot be the last word in the life of the Jewish community in Germany’. As these diverging views suggest, opting to live in the ‘land of the perpetrators’ represented both an unthinkable and a realistic choice. In the decade after the Holocaust, about 12,000 German-born Jews opted to remain in the Federal Republic of Germany (FRG) and comprised about half of its Jewish community. Rooted in the German language and typically married to non-Jewish spouses, they still had some connections to Germany. xSuch cultural and personal ties did not exist for the other half of West Germany’s Jewish community – its East European Jews. Between 1945 and 1948, 230,000 Jews sought refuge in occupied Germany from the violent outbursts of antisemitism in eastern Europe. Although by 1949 only 15,000 East European Jews had taken permanent residence in the FRG, those who stayed behind profoundly impacted upon Jewish life. More religiously devout than their German-Jewish counterparts, they developed a rich cultural tradition located mostly in southern Germany. But their presence also complicated Jewish life. From the late nineteenth century, relations between German and East European Jews historically were tense and remained so in the early postwar years; the highly acculturated German Jews looked down upon their less assimilated, Yiddish-speaking brothers. In the first decade after the war, integrating these two groups emerged as one of the most pressing tasks for Jewish community leaders.
Louis de Jong: Writing the History of Occupied Europe
Authors: MOORE BOB
Published: September 2005

Louis de Jong, who died on 15 March 2005, held a unique position as the official historian for the Netherlands during the Second World War. As head of the Rijksinstituut voor Oorlogsdocumentatie (RIOD), de Jong effectively came to dictate the research agenda on his country’s recent history for more than forty years after the conflict was over. For the Dutch, his name was synonymous not only with RIOD but also with the history of the German occupation from May 1940 to the final liberation in May 1945.
Persuasion: Ein oder zwei Prozesse?
Authors: Erb Hans-Peter , Kruglanski Arie W.
Published: September 2005

Zusammenfassung: Im Unimodel wird Persuasion aufgefasst als ein Urteilsprozess, bei dem Empfängerinnen und Empfänger persuasiver Kommunikation aus gegebener Evidenz durch Anwendung von Hintergrundwissen Schlussfolgerungen ziehen. Alternativ zu Zwei-Prozess-Modellen der Persuasion stellen im Unimodel inhaltliche Argumente und heuristische/periphere Hinweisreize funktional äquivalente Informationstypen dar: Die Wirkung einer spezifischen Information auf Einstellungen hängt nicht davon ab, ob es sich um ein inhaltliches Argument oder um einen inhaltsunabhängigen Hinweisreiz handelt, sondern von einer Reihe von urteilsrelevanten Parametern. Befunde aus der Persuasionsforschung werden aus dieser Perspektive betrachtet. Darüber hinaus ergeben sich neue Vorhersagen, von deren empirischen Prüfungen wir berichten. Schließlich erfolgen eine Diskussion der Einwände von Zwei-Prozess-Theoretikern gegen die vorgestellte Ein-Prozess-Konzeption und ein Ausblick auf zukünftige Forschung.
Selbst schuld und trotzdem aggressiv?
Authors: Steinmetz Martina , Lewand Martin
Published: September 2005

Zusammenfassung: Nach Berkowitz kann jede Art von negativem Affekt nach einer Frustration den Anreiz für aggressive Reaktionen darstellen. Ob eine offene aggressive Reaktion erfolgt, ist jedoch abhängig von den kognitiven Verarbeitungsprozessen im Anschluss an den negativen Affekt. Innerhalb dieses Prozesses können z. B. Schuld-Attributionen und soziale Normen zum Tragen kommen. Fragestellung der vorliegenden Studie war, ob in Abhängigkeit vom sozialen Kontext (inner- vs. außerfamiliär) verbal-aggressive Reaktionen durch eigenes Verschulden einer Frustration gehemmt werden. N = 211 Vpn bearbeiteten 40 Schilderungen fiktiver Frustrationssituationen, wobei die Schuld an der Frustration (eigene vs. keine Schuld) und die Art des Interaktionspartners/der Interaktionspartnerin (Familienmitglied vs. Fremde/r) variiert wurde. Wie vorhergesagt zeigten die Vpn bei eigener Schuld an der Frustration weniger verbal-aggressive Reaktionen als bei Frustrationen, an denen sie unschuldig waren. Innerhalb der Familie fiel der Effekt der Schuld aber geringer aus als bei fremden Interaktionspartner/inne/n. Diskutiert wird, welche Faktoren aggressive Reaktionen trotz eigener Schuld begünstigen.
Molecular-dynamics simulations of alkaline-earth metal cations in water by atom-bond electronegativity equalization method fused into molecular mechanics
Authors: Yang Zhong-Zhi , Li Xin
Published: September 2005

Intermolecular potential for alkaline-earth metal (Be2+, Mg2+, and Ca2+) cations in water has been derived using the atom-bond electronegativity equalization method fused into molecular mechanics (ABEEM/MM), and it is consistent with what was previously applied to the hydration study of the monovalent cations. Parameters for the effective interaction between a cation and a water molecule were determined, reproducing the ab initio results. The static, dynamic, and thermodynamic properties of Be2+(aq), Mg2+(aq), and Ca2+(aq) were studied using these potential parameters. Be2+ requires a more complicated form of the potential function than Mg2+ and Ca2+ in order to obtain better fits. Strong influences of the twofold charged cations on the structures of the hydration shells and some other properties of aqueous ionic solutions are discussed and compared with the results of a previous study of monovalent cations in water. At the same time, comparative study of the hydration properties of each cation is also discussed. This work demonstrates that ABEEM/MM provides a useful tool in the exploration of the hydration of double-charged cations in water.
Quantum-dot growth simulation on periodic stress of substrate
Authors: Zhao Chang , Chen Y. H. , Cui C. X. , Xu B. , Sun J. , Lei W. , Lu L. K. , Wang Z. G.
Published: September 2005

InAs quantum dots (QDs) are grown on the cleaved edge of an InxGa1−xAs∕GaAs supperlattice experimentally and a good linear alignment of these QDs on the surface of an InxGa1−xAs layer has been realized. The modulation effects of periodic strain on the substrate are investigated theoretically using a kinetic Monte Carlo method. Our results show that a good alignment of QDs can be achieved when the strain energy reaches 2% of the atomic binding energy. The simulation results are in excellent qualitative agreement with our experiments.
Thermally activated escape rate for the Brownian motion of a fixed axis rotator in an asymmetrical double-well potential for all values of the dissipation
Authors: Kalmykov Yuri P. , Titov Sergey V. , Coffey William T.
Published: September 2005

The Kramers theory of the escape rate of a Brownian particle from a potential well as extended by Mel’nikov and Meshkov, [J. Chem. Phys. 85, 1018 (1986)] is used to evaluate the relaxation times and the dynamic susceptibility for the rotational Brownian motion of fixed axis rotators in an asymmetric double-well potential. An expression for the escape rate valid for all values of the dissipation including the very low damping (VLD), very high damping (VHD), and crossover regimes is derived. It is shown that this expression provides a good asymptotic estimate of the inverse of the smallest nonvanishing eigenvalue λ1 of the underlying Fokker-Planck operator calculated by using the matrix-continued fraction method. For low barriers, where the Mel’nikov and Meshkov approach is not applicable, analytic equations for the correlation time τ‖ of the longitudinal dipole correlation function in the VLD and VHD limits are derived and a simple extrapolating equation valid for all values of the damping is proposed.
Deep levels by proton and electron irradiation in 4H–SiC
Authors: Castaldini Antonio , Cavallini Anna , Rigutti Lorenzo , Nava Filippo , Ferrero Sergio , Giorgis Fabrizio
Published: September 2005

The effects on 4H-silicon carbide epilayers of irradiation with protons and electrons having particle energies, respectively, of 6.5 and 8.2MeV were carefully studied and critically compared. In detail, the electronic levels associated with the irradiation-induced defects were analyzed by current-voltage characteristics and deep-level transient spectroscopy (DLTS) measurements up to 550K. In the same temperature range the apparent free-carrier concentration was measured by capacitance-voltage characteristics in order to monitor compensation effects due to the deep levels associated with the induced defects. Introduction rate, enthalpy, and capture cross section of such deep levels were compared. We found that a set of deep levels (at ET=0.39eV, ET=0.65eV, and ET=0.75eV) is the same in both cases of proton and electron irradiations, whereas two other pairs of levels (S1, ET=0.20eV and S1*, ET=0.23eV; S5, ET=1.09eV and S5*, ET=0.89eV) appearing in the same temperature range within the DLTS spectra should be associated with different defect complexes according to the irradiation type. Some conclusions regarding the microscopic nature of the defects related to the deep levels have been drawn.
Ground- and excited-state electronic structure of an iron-containing molecular spin photoswitch
Authors: Rodriguez Jorge H.
Published: September 2005

The electronic structure of the cation of [Fe(ptz)6](BF4)2, a prototype of a class of complexes that display light-induced excited-state spin trapping (LIESST), has been investigated by time-independent and time-dependent density-functional theories. The density of states of the singlet ground state reveals that the highest occupied orbitals are metal centered and give rise to a low spin configuration Fe2+(3dxy↑↓3dxz↑↓3dyz↑↓) in agreement with experiment. Upon excitation with light in the 2.3–3.3eV range, metal-centered spin-allowed but parity-forbidden ligand field (LF) antibonding states are populated which, in conjunction with electron-phonon coupling, explain the experimental absorption intensities. The computed excitation energies are in excellent agreement with experiment. Contrary to simpler models we show that the LF absorption bands, which are important for LIESST, do not originate in transitions from the ground to a single excited state but from transitions to manifolds of nearly degenerate excited singlets. Consistent with crystallography, population of the LF states promotes a drastic dilation of the ligand cage surrounding the iron.
On the theory of the CO+OH reaction, including H and C kinetic isotope effects
Authors: Chen Wei-Chen , Marcus R. A.
Published: September 2005

The effect of pressure, temperature, H∕D isotopes, and C isotopes on the kinetics of the OH+CO reaction are investigated using Rice-Ramsperger-Kassel-Marcus theory. Pressure effects are treated with a step-ladder plus steady-state model and tunneling effects are included. New features include a treatment of the C isotope effect and a proposed nonstatistical effect in the reaction. The latter was prompted by existing kinetic results and molecular-beam data of Simons and co-workers [J. Phys. Chem. A 102, 9559 (1998); J. Chem. Phys. 112, 4557 (2000); 113, 3173 (2000)] on incomplete intramolecular energy transfer to the highest vibrational frequency mode in HOCO*. In treating the many kinetic properties two small customary vertical adjustments of the barriers of the two transition states were made. The resulting calculations show reasonable agreement with the experimental data on (1) the pressure and temperature dependence of the H∕D effect, (2) the pressure-dependent C12∕C13 isotope effect, (3) the strong non-Arrhenius behavior observed at low temperatures, (4) the high-temperature data, and (5) the pressure dependence of rate constants in various bath gases. The kinetic carbon isotopic effect is usually less than 10 per mil. A striking consequence of the nonstatistical assumption is the removal of a major discrepancy in a plot of the kOH+CO∕kOD+CO ratio versus pressure. A prediction is made for the temperature dependence of the OD+CO reaction in the low-pressure limit at low temperatures.
A polymer high-k dielectric insulator for organic field-effect transistors
Authors: Müller Klaus , Paloumpa Ioanna , Henkel Karsten , Schmeisser Dieter
Published: September 2005

We report on organic field-effect transistors with enhanced gate effects using the soluble copolymer poly(vinylidene fluoride-trifluoroethylene) for the dielectric layer. The layer has a measured relative dielectric constant of about 11 (at 1kHz), which enables operation voltages smaller than for the organic insulator polymethylmetacrylate (ε=3.3 at 1kHz).
Anisotropic thermal diffusivity of aligned multiwall carbon nanotube arrays
Authors: Borca-Tasciuc T. , Vafaei S. , Borca-Tasciuc D.-A. , Wei B. Q. , Vajtai R. , Ajayan P. M.
Published: September 2005

A photothermoelectric technique was employed to determine the anisotropic thermal diffusivity of thick arrays of multiwalled carbon nanotubes grown by chemical-vapor deposition. The thermal diffusivity along the alignment direction was also determined using a self-heating 3ω method. The agreement between the measured thermal diffusivities with the two techniques is between 2% and 13% in the tested temperature range. The thermal diffusivity along the alignment direction decreases slightly with temperature in the 80–300-K temperature range and is ∼ two orders of magnitude smaller than the thermal diffusivity along the planes of graphite. The thermal diffusivity across the alignment direction is ∼25 times smaller than along the alignment direction and is between 50% and five times smaller than the thermal diffusivity across the planes of graphite in the measured temperature range.
Solution processible organic transistors and circuits based on a C70 methanofullerene
Authors: Anthopoulos Thomas D. , de Leeuw Dago M. , Cantatore Eugenio , van ’t Hof Patrick , Alma Jan , Hummelen Jan C.
Published: September 2005

We demonstrate ambipolar charge transport in organic field-effect transistors based on the solution processible methanofullerene [6,6]-phenyl-C71-butyric acid methyl ester ([70]PCBM). The electron mobility measured in the linear and saturated regimes is approximately equal and of the order of 1×10−3cm2∕Vs. In the linear regime, mobility is thermally activated with a strong gate bias dependence. The p-channel hole mobility is lower with a maximum value of 2×10−5cm2∕Vs. The n- and p-channel operations are characterized by a low (∼∣3∣V) and a high (∼∣50∣V) switch-on voltage, respectively, with the on-off current ratio on the order of 104 for both channels. Although the present findings are qualitatively similar to those reported previously for C60-methanofullerene-based transistors, [70]PCBM devices are more stable and easier to reproduce. By making use of this property we are able to demonstrate functional unipolar and complementarylike logic circuits with promising operating characteristics.
Defect dynamics in annealed ZnO by positron annihilation spectroscopy
Authors: Dutta Sreetama , Chakrabarti Mahuya , Chattopadhyay S. , Jana Debnarayan , Sanyal D. , Sarkar A.
Published: September 2005

As-supplied polycrystalline ZnO samples (purity 99.9% from Sigma-Aldrich, Germany) have been annealed at different temperatures and subsequently characterized by positron annihilation spectroscopy, x-ray-diffraction (XRD) analysis, thermogravimetric analysis (TGA), and resistivity measurements. Positron annihilation lifetime analysis and coincidence Doppler-broadened electron-positron annihilation γ-radiation (CDBEPAR) line-shape measurements have been employed at a time to identify the nature of defects in differently annealed ZnO materials. Annealing up to 300°C, an increase of defect lifetime (τ2) as well as shape parameter (S parameter) has been observed. Further annealing causes a large decrease of τ2 and S parameter. TGA study shows considerable mass loss from ZnO as the annealing temperature is increased above 300°C. This is possibly due to oxygen evaporation from the sample. The c-axis lattice parameter, extracted from the XRD spectra, shows an increase due to annealing above 600°C, which is a signature of the presence of a huge number of oxygen vacancies. Resistivity variations of the annealed samples are also consistent with the TG and XRD analyses. The ratio curve analysis of the CDBEPAR spectra successfully probes the change in zinc-related vacancy defects in annealed ZnO.
Equation of state and reaction rate for condensed-phase explosives
Authors: Wescott B. L. , Stewart D. Scott , Davis W. C.
Published: September 2005

The wide-ranging equation of state is a nonideal equation of state based on empirical fitting forms argued from thermodynamic considerations that yield the proper physical features of detonation. The complete equation of state forms are presented and the equation of state and a reaction rate are calibrated for the condensed-phase explosive PBX-9502. Experimental overdriven Hugoniot data are used to calibrate the products equation of state off the principal isentrope passing through the Chapman-Jouguet state. Shock Hugoniot data are used to calibrate the reactants equation of state. The normal detonation shock speed-shock curvature data (Dn−κ) from rate-stick measurements and shock initiation data from wedge tests are used to calibrate the reaction rate. Simulations are carried out that predict detailed particle velocity transients that are measured experimentally with embedded electromagnetic gauge measurements from gas-gun experiments. Multidimensional simulations of steady detonation in a right circular cylinder rate stick are carried out and compared with experiment.
Predicted electrical properties of modulation-doped ZnO-based transparent conducting oxides
Authors: Cohen D. J. , Barnett S. A.
Published: September 2005

A one-dimensional Poisson/Schrödinger program has been used to predict the effect of layer thicknesses, donor concentration, and band-gap offset on the electrical properties of transparent conducting modulation-doped ZnO∕ZnMgO multilayer structures. Mobilities as high as 145cm2∕Vs were predicted for a structure with an average carrier density of 3.8×1018cm−3 and a resistivity of 1×10−2Ωcm; for a comparable resistivity in monolithic ZnO, the mobility would be lower ∼30cm2∕Vs and the carrier density would be higher, leading to higher optical absorption. However, it was found that the maximum sheet electron density that could be transferred from the doped to the undoped layers was ∼1013cm−2, limiting the lowest calculated resistivity to ∼1.5×10−3Ωcm. The optimal thicknesses to simultaneously achieve high mobility and low resistivity were 2–5nm for both the pure ZnO and ZnMgO:Al layers. For ZnO thicknesses above this range the resistivity steadily increased, and below 2nm the mobility decreased. For ZnMgO:Al thicknesses increased above this range, the mobility rapidly decreased, whereas decreasing below 2nm increased the resistivity. The effect of the pure ZnMgO set-back layer thickness on mobility is discussed and a spacer layer of ∼1.5nm is proposed for ZnO∕ZnMgO multilayers. The effect of ZnO layer thickness on possible intersubband scattering is also discussed.
High-throughput x-ray characterization system for combinatorial materials studies
Authors: Luo Zhenlin , Geng Bin , Bao Jun , Liu Cihui , Liu Wenhan , Gao Chen , Liu Zhiguo , Ding Xunliang
Published: September 2005

We have developed a high-throughput x-ray characterization system, which can rapidly screen structure, composition and x-ray scintillation of combinatorial materials libraries using energy-dispersive x-ray diffraction, x-ray fluorescence, and x-ray photoluminescence. This system consists of an x-ray source, a polycapillary x-ray lens, one or two x-ray energy detectors, and a fiber optic spectrometer. A Windows-based software package was also developed to control the measurement system and data acquisition automatically. Examples are also demonstrated to show the applicability of this system.
Compression test system for a single submicrometer particle
Authors: Yoshida Mikiko , Ogiso Hisato , Nakano Shizuka , Akedo Jun
Published: September 2005

A compression test system was developed for measuring the strength of a single particle with a cross-sectional dimension of less than 1μm. The test system used a small diamond plate that has a flat platen to compress the particle on a diamond substrate. To avoid compressing multiple particles and to avoid direct contact between the platen and the substrate, the flat area was comparable in size to the tested particle. Mechanical processes such as polishing, however, have difficulty in fabricating such a small area. Here, fabrication of a micrometer-sized flat area was achieved by using focused ion beam technology. The resulting compression test system successfully measured the strength of a single submicrometer particle. Results showed that the mean strength of alumina particle with nominal mean diameter of 0.7μm was 2.9GPa.
Effect of the gas mixing technique on the plasma potential and emittance of the JYFL 14 GHz electron cyclotron resonance ion source
Authors: Tarvainen O. , Suominen P. , Ropponen T. , Kalvas T. , Heikkinen P. , Koivisto H.
Published: September 2005

The effect of the gas mixing technique on the plasma potential, energy spread, and emittance of ion beams extracted from the JYFL 14 GHz electron cyclotron resonance ion source has been studied under various gas mixing conditions. The plasma potential and energy spread of the ion beams were studied with a plasma potential instrument developed at the Department of Physics, University of Jyväskylä (JYFL). With the instrument the effects of the gas mixing on different plasma parameters such as plasma potential and the energy distribution of the ions can be studied. The purpose of this work was to confirm that ion cooling can explain the beneficial effect of the gas mixing on the production of highly charged ion beams. This was done by measuring the ion-beam current as a function of a stopping voltage in conjunction with emittance measurements. It was observed that gas mixing affects the shape of the beam current decay curves measured with low charge-state ion beams indicating that the temperature and∕or the spatial distribution of these ions is affected by the mixing gas. The results obtained in the emittance measurements support the conclusion that the ion temperature changes due to the gas mixing. The effect of the energy spread on the emittance of different ion beams was also studied theoretically. It was observed that the emittance depends considerably on the dispersive matrix elements of the beam line transfer matrix. This effect is due to the fact that the dipole magnet is a dispersive ion optical component. The effect of the energy spread on the measured emittance in the bending plane of the magnet can be several tens of percent.
Absence of enhanced stability in fully deuterated amorphous silicon thin-film transistors
Authors: Wehrspohn Ralf B. , Lin Shufan , Flewitt Andrew J. , Milne William I. , Powell Martin J.
Published: September 2005

The stability of fully deuterated amorphous silicon (a-Si:D) thin-film transistors is compared with their hydrogenated equivalent (a-Si:H) in terms of gate bias stress. The amorphous silicon channel and silicon nitride gate insulator layers were deposited by radio-frequency plasma-enhanced chemical-vapor deposition. The use of SiD4 rather than SiH4 for the deposition of a-Si:D changes the physical properties of the plasma given the same conditions of rf power, pressure, and gas flow rates. Consequently, a higher gas pressure is required to produce a-Si:D at the same growth rate and with similar bulk properties as a-Si:H. It is shown that a-Si:H and a-Si:D deposited at the same growth rate have very similar structural properties. Therefore transistors deposited at the same growth rate may be more sensibly compared to determine the effect of replacing H with D in amorphous silicon without significantly changing the silicon continuous random network. Using this criterion for comparison, no detectable difference is observed between hydrogenated and deuterated transistors in terms of stability under the application of a gate bias. The experimental results rule out the possibility of a giant isotopic effect in amorphous silicon. Furthermore, this result supports the idea that the rate-limiting step for dangling-bond defect creation in amorphous silicon is the breaking of a weak Si–Si bond, rather than breaking of a Si–H bond.
Effect of domain and grain shapes on the dynamical behavior of polycrystalline ferrites: Application to the initial permeability
Authors: Gelin Philippe , Quéffélec Patrick , Le Pennec François
Published: September 2005

This paper describes a theoretical approach to calculate the permeability tensor of polycrystalline ferrites in various magnetization states, from the completely demagnetized state to saturation. Demagnetizing dynamic fields related to the magnetic domain and grain shapes are introduced in the initial equations to describe the interactions between domains in a grain and between grains. In this paper, we focus on the calculation of the initial permeability of polycrystalline ferrites. Results obtained from the model are compared in a completely demagnetized state to those given by the well-known Schloemann model and to experiments. In all the models given in the literature, an unusually high value of the damping factor must be introduced into the calculations to correctly describe the low-field loss region. Values of the damping factor comparable to those calculated from the measured resonance linewidth of ferrites permit the prediction of the spreading of the magnetic losses as a function of frequency experimentally observed at low bias fields and especially in the demagnetized state.
Effects of morphology on the electronic and photoluminescence properties of hydrogenated silicon nanowires
Authors: Migas D. B.
Published: September 2005

By means of first-principles calculations we show that hydrogenated silicon nanowires in the ⟨001⟩ orientation can have a direct band gap with appreciable oscillator strength of the first direct transition if their surface is characterized by dimers displaying the SiH species. The breaking of some dimers (the SiH2 species) seems to help in stabilizing the direct nature of the gap of such nanostructures with increasing diameters. We also discuss how our findings can explain the efficient photoluminescence from porous silicon.
Broadband infrared emission from Er–Tm:Al2O3 thin films
Authors: Xiao Zhisong , Serna R. , Afonso C. N. , Vickridge I.
Published: September 2005

Thin films of amorphous aluminum oxide (Al2O3) co-doped with Er3+ and Tm3+ have been synthesized by alternate pulsed laser deposition. When pumped at 794 nm a broad emission band over 1400–1700 nm is observed. Two peaks related to the 1540 nm band from Er3+ and to the 1640 nm band from Tm3+ are clearly distinguished. The photoluminescence intensity ratio of the 1640–1540 nm emissions has been controlled by modifying the Tm concentration. A spectrum with a fairly flat profile and a full width at half maximum of 230 nm is obtained for an Er concentration of 7.2×1019cm−3 and a [Tm]∕[Er] concentration ratio of 3. It is found that the Er3+ to Tm3+ energy transfer processes play an important role in the definition of the luminescent response. The large width of the emission band and the excellent optical and thermomechanical properties of the Er–Tm co-doped Al2O3 signal this system as a potential candidate for the development of broadband integrated optical amplifiers.
Turing pattern formation in coupled reaction-diffusion system with distributed delays
Authors: Ji Lin , Li Qian Shu
Published: September 2005

Turing pattern formation in coupled two-layer system with distributed delayed is investigated. Numerical simulations prove that, when the coupling is weak, it can apparently accelerate the formation process and enhance the spatial amplitude of the pattern. When it is strong, it will prolong the formation process or even inhibit the pattern and turn the whole system into bulk oscillatory state by its influence on the transient oscillatory state. If the coupling covers only part of the system, Turing pattern can be prominently oriented according to the shape of the coupling area at tiny coupling strength. However, if the coupling is too strong, the Turing pattern may also be destroyed. This means that in coupled systems, the delay effect in the cross-layer signal transfer may significantly influence the spatial character and/or the evolution dynamics in Turing pattern formation, even to destroy the pattern. This work is of practical significance in the study of Turing pattern in biosystems, where bilayer membranes or multilayer tissues are often found.
A nanotube-based field emission x-ray source for microcomputed tomography
Authors: Zhang J. , Cheng Y. , Lee Y. Z. , Gao B. , Qiu Q. , Lin W. L. , Lalush D. , Lu J. P. , Zhou O.
Published: September 2005

Microcomputed tomography (micro-CT) is a noninvasive imaging tool commonly used to probe the internal structures of small animals for biomedical research and for the inspection of microelectronics. Here we report the development of a micro-CT scanner with a carbon nanotube- (CNT-) based microfocus x-ray source. The performance of the CNT x-ray source and the imaging capability of the micro-CT scanner were characterized.
Single-crystalline nanotubes of IIB-VI semiconductors
Authors: Hu J. Q. , Bando Y. , Zhan J. H. , Liao M. Y. , Golberg D. , Yuan X. L. , Sekiguchi T.
Published: September 2005

Wurtzite-type CdS and CdSe nanotubes have been grown via a Sn nanowire-templated route under thermal annealing. The tubes are structurally uniform and defect-free single crystals, and partially or completely filled with Sn nanowires; most of the tubes display pin-like structures showing significant tapering along their axes. Cathodoluminescence spectra reveal that CdS and CdSe nanotubes have profound emission peaks at ∼512 and ∼724nm. The luminescence intensities vary between Sn filled and unfilled tube parts. Keeping in mind that ZnS and ZnSe nanotubes may also be synthesized using the similar technique, we propose that the present method is a universal synthetic route toward single-crystalline IIB-VI group semiconductor nanotubes.
Development and instrumentation of an integrated three–dimensional optical testing system for application in integrated circuit packaging
Authors: Su Fei , Chian Kerm Sin , Yi Sung , Dai Fulong
Published: September 2005

Measurement of hygrothermomechanical deformation is critical for the failure analysis and reliability evaluation of integrated circuit (IC) packages. Conventional methods, however, provide one– or two–dimensional measurements, and these measurements are not enough for accurate analysis and evaluation in many cases. In this paper, the development of a compact three-dimensional (3D) optical testing system based on moiré interferometry and Twyman-Green interferometry is described. Furthermore, a novel technique to simultaneously record the fringe patterns of three deformation fields with a single CCD camera is developed based on this 3D testing system. Some well-established measurement methods like thermal-mechanical-analyzer (TMA) and Taylor-Hobson stylus profilometer are used to verify the system performance. The results show good comparisons. In general, hygrothermomechanical deformation of IC packages during their fabrication and service can be measured comprehensively and dynamically using our 3D optical testing system, some drawbacks of the conventional optical methods and/or systems in the application of the IC packaging are overcome.
Electron cyclotron emission spectrometry on the Tokamak à Configuration Variable
Authors: Klimanov I. , Porte L. , Alberti S. , Blanchard P. , Fasoli A. , Goodman T. P.
Published: September 2005

Electron cyclotron emission (ECE) measurements are an important component of the diagnostic suite on the Tokamak à Configuration Variable (TCV) [F. Hoffman et al., Plasma Phys. Controlled Fusion 36, B277 (1994)]. A recently installed, 24-channel dual-conversion heterodyne radiometer covering the radio frequency range 65–100 GHz and viewing from the low-field side (LFS) of the tokamak greatly enhances the system and, in combination with an existing radiometer viewing from the high-field side (HFS), allows simultaneous measurements of emission from the HFS and LFS. In addition, the new radiometer has multiple lines of sight that can receive the emission perpendicular to the toroidal magnetic field as well as with a finite k‖ (wave vector parallel to magnetic field). Such flexibility allows the LFS radiometer to make standard measurements of thermal emission and nonstandard measurements of nonthermal, anisotropic emission. The toroidal line of sight allows access to overdense plasma via mode converted emission. The enhanced ECE diagnostic is described and examples of measurements made in various configurations are presented.
Detection of single magnetic bead for biological applications using an InAs quantum-well micro-Hall sensor
Authors: Mihajlović Goran , Xiong Peng , von Molnár Stephan , Ohtani Keita , Ohno Hideo , Field Mark , Sullivan Gerard J.
Published: September 2005

Room-temperature detection of a single commercial superparamagnetic bead (1.2μm in diameter) suitable for biological applications has been realized using an InAs quantum-well micro-Hall sensor. The detection was demonstrated using phase-sensitive detection on a single Hall cross as well as in a Hall gradiometry setup. The high signal to noise ratio, obtained in both configurations, promises detection of single nanometer-size particles by further miniaturization of the device to submicron dimensions.
Annealing behavior of hydrogen-plasma-induced n-type HgCdTe
Authors: Yang Keedong , Lee Yong Soo , Lee Hee Chul
Published: September 2005

In this letter, the effect of annealing in plasma-induced-type converted HgCdTe was observed. The Hg deficient annealing process reconverts the type converted n-HgCdTe into p-type. The activation energy of the process was determined to be 0.99eV regardless to the gas species used for the type conversion process. However, the absorption edge moved toward short-wave direction for hydrogen-plasma-treated sample. The absorption edge shift was observed even after the annealing process, which means the passivation and junction formation are separate phenomena.
Scalability of phononic crystal heterostructures
Authors: Ramprasad R. , Shi N.
Published: September 2005

Phononic (or acoustic) band structure calculations have been performed for a nanoscale HfO2–ZrO2 multilayer stack using first-principles methods at the atomistic level and by solving the acoustic wave equation at the continuum level, as a first step toward determining the length scales when conventional continuum acoustic band-gap treatments become inadequate. Transverse acoustic waves are the focus of this study. The material parameters that continuum acoustic band gap methods require, such as the mass density and transverse wave velocity of the components of the acoustic crystal (i.e., for HfO2 and ZrO2), were determined using separate phonon calculations of the corresponding bulk materials. Comparison of the phononic band structure for a nanoscale HfO2–ZrO2 multilayer stack calculated using first-principles and continuum methods indicates the need for careful treatments of wave propagation properties at these length scales.