bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization behavior of poly(ε‐caprolactone)/multiwalled carbon nanotube composites
Authors: Wu Tzong‐Ming , Chen Erh‐Chiang 
Published: December 2005

AbstractDifferential scanning calorimetry (DSC), polarized optical microscopy, and X‐ray diffraction methods were used to investigate the isothermal crystallization behavior and crystalline structure of poly(ϵ‐caprolactone) (PCL)/multiwalled carbon nanotube (MWNT) composites. PCL/MWNT composites were prepared via the mixing of a PCL polymer solution with carboxylic groups containing multiwalled carbon nanotubes (c‐MWNTs). Both Raman and Fourier transform infrared spectra indicated that carboxylic acid groups formed at both ends and on the sidewalls of the MWNTs. A transmission electron microscopy micrograph showed that c‐MWNTs were well separated and uniformly distributed in the PCL matrix. DSC isothermal results revealed that introducing c‐MWNTs into the PCL structure caused strongly heterogeneous nucleation induced by a change in the crystal growth process. The activation energy of PCL drastically decreased with the presence of 0.25 wt % c‐MWNT in PCL/c‐MWNT composites and then increased with increasing MWNT content. The result indicated that the addition of c‐MWNT to PCL induced heterogeneous nucleation (lower total activation energy) at a lower c‐MWNT content and then reduced the transportation ability of polymer chains during crystallization processes at a higher MWNT content (higher total activation energy). A correlation between the crystallization kinetics, melting behavior, and crystalline structure of PCL/c‐MWNT composites was also discussed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 598–606, 2006
Residual stresses and birefringence in injection molding of amorphous polymers: Simulation and comparison with experiment
Authors: Isayev A. I. , Shyu G. D. , Li C. T. 
Published: December 2005

AbstractA physical modeling and a two‐dimensional numerical simulation of the injection‐molding of a disk cavity by using a hybrid finite element method (FEM) and finite difference method (FDM) are presented. Three stages of the injection‐molding cycle––filling, packing, and cooling––are included. The total residual stresses are taken to be a sum of the flow stresses calculated using a compressible nonlinear viscoelastic constitutive equation and the thermal stresses calculated using a linear viscoelastic constitutive equation. The total residual birefringence is taken to be the sum of the flow birefringence related to the flow stresses through the stress–optical rule, and the thermal birefringence related to the thermal stresses through the photoviscoelastic constitutive equation. The Tait equation is used to describe the P‐V‐T relationship. The simulation shows that without packing the birefringence in the surface layer of moldings, with its maximum near the surface, is caused by the frozen‐in flow birefringence (flow stresses) and in the core region by the frozen‐in thermal birefringence (thermal stresses). With packing, a second birefringence maximum appears between the center and the position of the first maximum due to flow in the packing stage. The predicted birefringence profiles and extinction angle profiles are found to be in fair agreement with corresponding measurements in literature for disk moldings. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 622–639, 2006
Unusual phase behavior in mixtures of poly(ethylene oxide) and ethyl alcohol
Authors: Ho Derek L. , Hammouda Boualem , Kline Steven R. , Chen Wei‐Ren 
Published: December 2005

AbstractPoly(ethylene oxide) (PEO), soluble in both aqueous and organic solvents, is one of the most intriguing polymers. PEO solution properties have been extensively studied for decades; however, many of the studies have focused on specific properties, such as clustering, of PEO in aqueous solutions, and the behavior of PEO in organic solvents has not been adequately explored. The results presented here demonstrate that PEO crystallizes into a lamellar structure in ethyl alcohol after the mixture is quenched to room temperature from a temperature above the crystal melting point. Above the melting temperature, PEO completely dissolves in ethyl alcohol, and the mixture exhibits regular polymer solution thermodynamic behavior with an upper critical solution temperature (UCST) phase diagram. Remarkably, the UCST phase boundary is significantly below the melting temperature, and this indicates that the system undergoes a crystallization process before the phase separation can occur upon cooling and, therefore, possesses an unusual phase transition. The phase transition from the crystalline state to the miscible solution state is reversible upon heating or cooling and can be induced by the addition of a small amount of water. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 557–564, 2006
The role of a ‘retirement transition’ in the repopulation of rural areas
Authors: Stockdale Aileen 
Published: December 2005

AbstractTwo of the most important demographic trends to emerge in recent decades have been the growth of a highly mobile ageing population and a deconcentration of persons from urban to rural areas. This paper investigates Bures' (1997) retirement transition hypothesis for the mobility patterns of pre‐retirement age groups in relation to the repopulation of rural areas of England and Scotland. It incorporates household survey data relating to the migration patterns and decisions of those aged between 50 and 64 years. Evidence is obtained to support Bures' hypothesis. It is suggested that an economic transition accompanies any retirement transition. In addition, differences in the nature of the retirement transition are observed between the repopulation of rural England and Scotland. These trends have important policy implications for the future of rural areas. Copyright © 2006 John Wiley & Sons, Ltd.
Place, community education, gender and child mortality in North‐east India
Authors: Ladusingh Laishram , Singh Chungkham Holendro 
Published: December 2005

AbstractThis article examines the relevance of socio‐cultural and environmental factors in explaining child mortality in Northeast India, considered to be the most inaccessible region in the country. Using data from the Indian National Family Health Survey, we provide evidence that lack of hygiene in the household and poor women's engagement in physically demanding agriculture based work contributes to higher risk of child mortality. Unlike in other parts of India, female children have an edge over boys in childhood survival and living with paternal grandmother tends to lower the risk of child death in the first five years of life. Community education is found as the dominant factor outside the household to have a significant effect on child mortality. Copyright © 2006 John Wiley & Sons, Ltd.
Pt/Ga/C and Pt/C composite nanowires fabricated by focused ion and electron beam induced deposition
Authors: Li P. G. , Jin A. Z. , Tang W. H. 
Published: December 2005

AbstractPt/Ga/C and Pt/C composite nanowires have been fabricated using ion beam induced deposition (IBID) and electron beam induced deposition (EBID), respectively, with a dual beam focused ion beam system. The Pt/Ga/C composite nanowires usually exhibit a semiconducting character and their resistances increase greatly as the temperature decreases. However, the Pt/C composite nanowires show metallic behaviour above 2 K. The results suggest that EBID is more suitable than IBID for fabricating measuring electrodes for nanomaterials and devices in a single‐step process. It has also been found that the resistance of the Pt/C nanowires decreases abruptly around 20 K, which could arise from a possible new phase formed between Pt and C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic softening and giant magneto‐impedance effect of Co68Fe4Ni1Si15B12
Authors: Hoque S. Manjura , Hakim M. A. , Khan F. A. 
Published: December 2005

AbstractMagnetic softening and its correlation with the giant magneto‐impedance effect have been investigated for Co68Fe4Ni1Si15B12 subjected to different annealing temperatures. In the as‐cast condition the Curie temperature is 230 °C and the saturation magnetization is 72.3 emu/g. A very high value of initial permeability of around 59 × 103 and a low value of relative loss factor of the order of 10–6 have been obtained for samples annealed at 420 °C for 1 h. The sensitivity of the field dependence of the giant magneto‐impedance ratio (GMIR) for this annealing temperature is higher than that for as‐cast and other annealed samples. From X‐ray diffraction and differential scanning calorimetry results it has been found that for samples annealed at 420 °C for 1 h the ribbon is in a fully amorphous state. The extraordinary soft magnetic properties at this annealing temperature are mainly due to the structural relaxation, which determines the profile of the field dependence of the GMIR. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical characterisation of thick InN epilayers grown with a single or two step growth process on GaN(0001)
Authors: Delimitis A. , Gladkov P. , Komninou Ph. , Kehagias Th. , Arvanitidis J. , Ves S. , Katsikini M. , Dimakis E. , Georgakilas A. 
Published: December 2005

AbstractHigh resolution transmission electron microscopy (HRTEM), Raman spectroscopy and temperature dependent photoluminescence (PL) are employed to compare the structural and optical properties of compact InN films grown by molecular beam epitaxy (MBE) on GaN/Al2O3(0001) with a single‐step (S) or a two‐step (T) growth process. The S‐type film was grown at 300 °C, whilst the T‐type film was nucleated at the same temperature and overgrown at 410 °C. The T‐type film exhibits better structural and optical properties as indicated by a sharper InN/GaN interface, the lower threading dislocations density, sharper Raman peaks and higher intensity PL peaks. Quantitative comparison of the red‐shifted Raman E 22 peak and the lattice constants of S and T samples suggests that the InN epilayers are under different values of stress due to thermal reasons and point defects present in them. The PL emission peak difference of 32 meV between S and T provides further evidence of the unequal residual strain present in InN. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A comparative study on MOVPE InN films grown on 3c‐SiC/Si(111) and sapphire
Authors: Kobayashi T. , Cho M. S. , Sawazaki N. , Hashimoto A. , Yamamoto A. , Ito Y. 
Published: December 2005

AbstractThis paper reports the MOVPE growth of InN on a 3c‐SiC/Si template formed by C+‐ion implantation into Si(111). Properties of grown films on the template are compared with those grown on sapphire in the same run. By employing the nitridation process of the template at 900 °C for 30 min just before the GaN buffer growth, the buffer layer becomes to show uniform nucleation. This is due to the improved wettability of GaN layer on the template by the formation of Si–N bonds on the Si‐polar SiC layer. The surface mophology of InN film grown on the nitrided template is similar to that for a film grown on a sapphire. The film on the nitrided template shows strong photoluminescence with a peak energy of 0.70 eV at room temperature. The carrier concentration and Hall mobility are 7.6 × 1018 cm–3 and 630 cm2/Vs, respectively. These data are comparable to those for InN grown on the sapphire (0.71 eV, 6.5 × 1018 cm–3 and 870 cm2/Vs). Thus, the nitridation process of the 3c‐SiC/Si template is found to be effective to obtain high‐quality InN film. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time windows of spin squeezed states in a stripe phase
Authors: Peng Feng , Xingkun Man 
Published: December 2005

AbstractThe time evolution of the spin fluctuation in a stripe phase of a superconductor is studied. In a laser field with proper field strength and frequency, the amplitude of the fluctuation may be very small in some time regions (time windows), and even smaller than the level of the vacuum fluctuation. The corresponding states are called the spin squeezed states. The conditions for achieving the spin squeezed states are given, and a possible detecting scheme is presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antiferroelastic structural transitions in PrAlO3 by means of neutron diffraction
Authors: Watanabe S. , Hidaka M. , Yoshizawa H. , Wanklyn B. M. 
Published: December 2005

AbstractStructural phase transitions of the perovskite‐type PrAlO3 have been studied by using neutron diffraction. The results show that, on cooling, the structures are successively transformed from R$ \bar 3 $c (Phase II) to Imma (Phase III), Imma (Phase IV), I4/mcm (Phase V) by the 215‐K, 153‐K, and 122‐K transitions. The tilting schemes in Phase III, IV and V are mainly characterized by (ψa = ψc, ψb = 0), (ψa ≠ ψc, ψb = 0), and (ψc, ψa = ψb = 0), respectively, where ψa, ψb and ψc are rotational angles around a‐, b‐, and c‐primitive axes of the AlO6 octahedron. The refreezes of the condensed Rand R optical soft modes occurring at about 215 K and 122 K are interpreted by correlation with the cooperative Jahn–Teller distortion (JTD) of the Pr3+–4f orbitals in the PrO12 polyhedra. The phase IV is characterized as an intermediate state, in which the ψa tilts are continuously reduced by the JTD and disappear just above the 122‐K transition. The easy mobility of the domain walls suggests the PrAlO3 crystal to be of antiferroelastic nature, an unusual property that results from the cooperative displacements of O ions induced by the correlation between the antiphase tilts along primitive axes of the AlO6 octahedra and the JTD around Pr+3 ions in PrO12 polyhedra. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Creation of CsAu nanoclusters by UV‐light irradiation on CsBr:Au– crystals
Authors: Kawai Taketoshi , Yamano Asuka 
Published: December 2005

AbstractWe have investigated the optical absorption spectra of the CsBr:Au– crystals irradiated with an ultraviolet (UV) light. Before the UV‐light irradiation, the absorption bands associated with the isolated Au– ion (monomer) are observed in the energy region of UV. After a slight UV‐light irradiation, the absorption intensities of the monomer bands decrease and the absorption bands due to paired Au– ions appear around the monomer bands. Furthermore, UV‐light irradiation on the CsBr:Au– crystals brings about the appearance of several new absorption bands in the visible region. From the analogy with the aggregation of the F centers in alkali halide crystals, the new absorption bands are attributed to the aggregate centers of the Au– ions. They can also be regarded as the CsAu nanocluster constructed from the Cs+ cations and the Au– anions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Free‐exciton absorption in bulk CdTe: temperature dependence
Authors: Horodyský P. , Hlídek P. 
Published: December 2005

AbstractThe absorption spectra in the free‐exciton region were measured on micrometer‐thick samples of bulk CdTe crystals. Analysis of the Urbach tail showed that the absorption edge is dominated by the free‐exciton transitions even at room temperature. The temperature dependence of the fundamental energy gap was obtained from the free‐exciton resonance from 4 K to 500 K. The value of 1.526 eV is proposed for the energy gap at 300 K. A comparison with the temperature dependencies of other works is given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Yakubovich–Kalman–Popov lemma and stability analysis of dynamic output feedback systems
Authors: Johansson Rolf , Robertsson Anders 
Published: December 2005

AbstractThis paper presents theory related to stability analysis and stability criteria relevant for observer‐based feedback control systems. To this purpose, a special formulation of the Yakubovich–Kalman–Popov (YKP) lemma is provided. We exploit that controllability is not necessary for existence of Lur'e–Lyapunov functions as used in stability criteria. Constructive means for dynamic output feedback stabilization, positivity, factorization and passivity are provided. Copyright © 2005 John Wiley & Sons, Ltd.
Practical optimal control of fed‐batch bioreactors for the waste water treatment
Authors: Betancur Manuel J. , Moreno Jaime A. , Moreno‐Andrade Iván , Buitrón Germán 
Published: December 2005

AbstractOptimal operation of fed‐batch bioreactors is an important practical issue. Since control actions are saturation‐limited, the optimal control consists usually of both singular and bang–bang arcs. However, its realization requires good model knowledge and also the measurement of all state variables, requirements rarely satisfied in real applications. In this paper a method is proposed, for a class of bioreactors, to robustly optimize the operation when few measured variables are available and the model is uncertain. Such control law is justified and its properties analysed. The case of a bioreactor for treating toxicants in a waste water treatment plant is thoroughly studied, and experimental results in a lab‐scale bioreactor are presented. The method can be also applied for other applications, as in biotechnology. Copyright © 2005 John Wiley & Sons, Ltd.
The Outcome of Cervical Exploration for Asymptomatic and Symptomatic Patients with Primary Hyperparathyroidism
Authors: Abbas Jaber S. , Hashem Suzan I. , Faraj Walid G. , Khalifeh Mohammad J. , Horani Mukbil H. , Salti Ibrahim S. 
Published: December 2005

AbstractThis study examined the success and safety of cervical exploration in patients with primary hyperparathyroidism (HPT). The presentation, pathologic findings, and outcome of patients with asymptomatic primary HPT were compared with those with symptomatic disease. Records of patients undergoing cervical exploration for primary HPT from January 1993 until December 31, 2003, were reviewed. Information collected consisted of preoperative symptoms, calcium and parathormone (PTH) levels, imaging studies, operative findings, pathology, and outcome of the patients. The groups with asymptomatic and symptomatic primary HPT were compared. In all, 139 patients were studied; 31 (22.3%) were asymptomatic (group I), and 108 (77.7%) had symptoms (group II). The two groups were also comparable regarding mean age, sex, and the yield of the imaging studies. The mean preoperative serum calcium level was comparable in the two groups (11.1mg/dl versus 11.3 mg/dl). However, PTH levels were significantly lower in group I than in group II (142 pg/dl versus 283 pg/dl, P = 0.01). The weight of the adenoma was also significantly less in group I than in group II (1082 mg versus 1679 mg P = 0.079). The outcome of the surgical exploration was comparable in the two groups with an immediate success rate close to 98% and a long‐term success rate of 95.4%. Cervical exploration and parathyroidectomy in patients with primary HPT is a safe procedure with a high success rate and favorable outcome.
Predicting Postoperative Mortality in Patients Undergoing Colorectal Surgery
Authors: Slim Karem , Panis Yves , Alves Arnaud , Kwiatkowski Fabrice , Mathieu Pierre , Mantion Georges 
Published: December 2005

AbstractWell‐known and suitable instruments for surgical audit are the POSSUM and P‐POSSUM scoring systems. But these scores have not been well validated across the countries. The objective of the present study was to assess the predictive value of scores for colorectal surgery in France. Patients operated on for colorectal malignant or diverticular diseases, whether electively or on emergency basis, within a 4‐month period were included in a prospective multicenter study conducted by the French Association for Surgery (Association Française de Chirurgie, AFC). The main outcome measure was postoperative in‐hospital mortality. Independent factors leading to death were assessed by multivariate logistic regression analysis (AFC‐index). The ratio of expected versus observed deaths was calculated, and the predictive value of the POSSUM and P‐POSSUM scores were analyzed by the receiver operating characteristic (ROC) curve. A total of 1426 patients were included. The in‐hospital death rate was 3.4%. Four independent preoperative factors (AFC‐index) have been found: emergency surgery, loss of more than 10% of weight, neurological disease history, and age > 70 years. POSSUM had a poor predictive value; it overestimated postoperative death in all cases. P‐POSSUM had a good predictive value, except for elective surgery, where it overestimated postoperative death twofold. The predictive value of the AFC‐index was also good. It had the same sensitivity and specificity as the P‐POSSUM. POSSUM has not been validated in France in the field of colorectal surgery. P‐POSSUM was as predictive as the AFC‐index which is a simpler instrument based on four clinical parameters (without any mathematical formulas).
Clinical Significance of Metastasis to the Central Compartment from Papillary Microcarcinoma of the Thyroid
Authors: Ito Yasuhiro , Tomoda Chisato , Uruno Takashi , Takamura Yuuki , Miya Akihiro , Kobayashi Kaoru , Matsuzuka Fumio , Kuma Kanji , Miyauchi Akira 
Published: December 2005

AbstractWe previously demonstrated that for papillary microcarcinoma (PMC), (1) patients with lateral lymph node metastasis detected on preoperative ultrasonography (US) are more likely to develop recurrence, and (2) dissection of the lateral compartment does not improve the prognosis of patients without US‐detectable lateral metastasis. In this study, we focused on metastasis from PMC to the central compartment. We investigated the clinical significance of lymph nodes in the central compartment using the same series of 600 patients as used in the previous study. Ultrasound‐diagnosed central node metastasis could be found in 30 patients (20.0%). Although the specificity of US for detecting central node metastasis was 99.1%, sensitivity was only 10.9%. Neither US‐diagnosed nor pathologically confirmed central node metastasis affected the disease‐free survival (DFS) rate of PMC patients. Furthermore, in cases where PMC was located only in one lobe, central node dissection in the contralateral lobe did not improve the DFS rate. These findings suggest that, for PMC, (1) US is an insensitive technique for detecting the central node metastasis, (2) the presence of central node metastasis is unrelated to DFS of patients, and (3) when performing lobectomy for PMC involving only one lobe, dissection of the central compartment in the contralateral lobe is optional.