bluuebunny/crossref_metadata_2025 huggingface dataset:
Immune-mediated Neutropenia in the Neonate
Authors: Black L. Vandy , Maheshwari Akhil
Published: September 2009

Neutropenia is a relatively common finding in ill neonates, occurring in approximately 32,000 infants each year in the United States. In this patient population, immune-mediated neutropenia results from the antibody-mediated destruction of neutrophils and is associated with such disorders as alloimmune neonatal neutropenia, neonatal autoimmune neutropenia, and autoimmune neutropenia of infancy. Such conditions only recently have begun to be understood and often are problematic in terms of clinical identification and laboratory confirmation. This article reviews the clinical presentation, laboratory diagnosis, and treatment options for these three disorders.
Challenges of Accurately Measuring and Using BMI and Other Indicators of Obesity in Children
Authors: Himes John H.
Published: August 2009

BMI is an important indicator of overweight and obesity in childhood and adolescence. When measurements are taken carefully and compared with appropriate growth charts and recommended cutoffs, BMI provides an excellent indicator of overweight and obesity that is sufficient for most clinical, screening, and surveillance purposes. Accurate measurements of height and weight requirethat adequate attention be given to data collection and management. Choosing appropriate equipment and measurement protocols and providing regular training and standardization of data collectors are critical aspects that apply to all settings in which BMI will be measured and used. Proxy measures for directly measured BMI, such as self-reports or parental reports of height and weight, are much less preferred and should only be used with caution and cognizance of the limitations, biases, and uncertainties attending these measures. There is little evidence that other measures of body fat such as skinfolds, waist circumference, or bioelectrical impedance are sufficiently practicable or provide appreciable added information to be used in the identification of children and adolescents who are overweight or obese. Consequently, for most clinical, school, or community settings these measures are not recommended for routine practice. These alternative measures of fatness remain important for research and perhaps in some specialized screening situations that include a specific focus on risk factors for cardiovascular or diabetic disease. Pediatrics 2009;124:S3-S22
BMI Screening and Surveillance: An International Perspective
Authors: James William Philip Trehearne , Lobstein Tim
Published: August 2009

International efforts to screen children have previously focused on the problem of malnutrition in the preschool years. The new World Health Organization–derived but US-based data for “optimum” growth in school-aged children may not be accepted in more than a few countries. Currently, an international perspective suggests that those school-aged children's BMIs that, on a percentile-ranking basis, track to adult BMIs of ≥25 kg/m2 are likely to be associated with an appreciable increased risk of the comorbidities associated with weight gain. There is limited evidence on the value of individually directed help for children with higher BMIs as a national policy, but national surveillance systems are badly needed to allow a better focus on the development of both public health and individual treatment policies.
The Role of Culture in the Context of School-Based BMI Screening
Authors: Fitzgibbon Marian L. , Beech Bettina M.
Published: August 2009

The high prevalence of overweight and obesity is a significant public health concern in the United States. Minority populations are disproportionately affected, and the impact of obesity on minority children is especially alarming. In this article we discuss school-based BMI reporting, which is intended to increase parental awareness of their children's weight status. This information could potentially lead parents of overweight and obese children to carefully examine and possibly change their children's diet and activity patterns. However, any program related to child weight status must consider culturally defined aspects of body size and shape. In other words, the cultural context in which information on child BMI is presented to and received by parents must be considered. In this article we review parental perceptions of child weight. Multiple studies have shown that parents of overweight or obese children often fail to correctly perceive their children as overweight. Possible reasons for, and implications of, this misperception of child weight status among minority parents are then explored within a cultural framework. The PEN-3 model is used to examine influences on health behaviors and could help inform the development of a culturally sensitive BMI-notification program for minority parents. Reporting materials congruent with the social and cultural values and practices of the target audience are likely to maximize program effectiveness. A culturally based BMI-notification program should be conceptualized as a small step in a comprehensive plan to reduce childhood obesity and improve the current and future health of minority children.
Surveillance, Screening, and Reporting Children's BMI in a School-Based Setting: A Legal Perspective
Authors: Ryan Kevin W.
Published: August 2009

The rising epidemic of childhood and adolescent obesity is placing a heretofore unprecedented physical and fiscal burden on individuals and communities. Federal and state government officials who seek to determine the scope of the problem are using a spectrum of tools that include reporting, screening, and surveillance initiatives. The extent of authority to use these public health tools is yet to be determined, especially in the area of data use, privacy, and liability as government officials balance the need to improve public health with individual freedom and autonomy.
BMI Measurement in Schools
Authors: Nihiser Allison J. , Lee Sarah M. , Wechsler Howell , McKenna Mary , Odom Erica , Reinold Chris , Thompson Diane , Grummer-Strawn Larry
Published: August 2009

BACKGROUND AND OBJECTIVE: School-based BMI measurement has attracted attention across the nation as a potential approach to address obesity among youth. However, little is known about its impact or effectiveness in changing obesity rates or related physical activity and dietary behaviors that influence obesity. This article describes current BMI-measurement programs and practices, research, and expert recommendations and provides guidance on implementing such an approach.

METHODS: An extensive search for scientific articles, position statements, and current state legislation related to BMI-measurement programs was conducted. A literature and policy review was written and presented to a panel of experts. This panel, comprising experts in public health, education, school counseling, school medical care, and parenting, reviewed and provided expertise on this article.

RESULTS: School-based BMI-measurement programs are conducted for surveillance or screening purposes. Thirteen states are implementing school-based BMI-measurement programs as required by legislation. Few studies exist that assess the utility of these programs in preventing increases in obesity or the effects these programs may have on weight-related knowledge, attitudes, and behaviors of youth and their families. Typically, expert organizations support school-based BMI surveillance; however, controversy exists over screening. BMI screening does not currently meet all of the American Academy of Pediatrics’ criteria for determining whether screening for specific health conditions should be implemented in schools.

CONCLUSION: Schools initiating BMI-measurement programs should adhere to safeguards to minimize potential harms and maximize benefits, establish a safe and supportive environment for students of all body sizes, and implement science-based strategies to promote physical activity and healthy eating.
The effects of ruthenium-oxidation states on Ru dissolution in PtRu thin-film electrodes
Authors: Park Yejun , Lee Byungjoo , Kim Chunjoong , Oh Yuhong , Nam Seunghoon , Park Byungwoo
Published: August 2009

The effects of ruthenium (Ru)-oxidation states were investigated on Ru dissolution from PtRu thin-film electrodes, with the 200 cycles between 0.4 and 1.05 V (versus normal hydrogen electrode). The Ru-oxidation states of the PtRu thin films were systematically modified by an anodic (oxidation) treatment. The anodic-treated PtRu electrodes, whose methanol-oxidation activity was similar to untreated electrodes before the 200 cycles, showed a remarkable decrease in methanol oxidation after the cycles, because of the Ru dissolution from the PtRu surface. The results suggest that the Ru-oxide species are the origin of Ru dissolution in the PtRu alloy.
Effect of prestrain on microstructure and mechanical behavior of aged Ti–10V–2Fe–3Al alloy
Authors: Chen Wei , Song Zhenya , Xiao Lin , Sun Qiaoyan , Sun Jun , Ge Peng
Published: August 2009

The effect of prestrain on microstructure and mechanical behavior of aged Ti–10V–2Fe–3Al alloy was investigated. The results showed that prestrain caused the tensile strength to decrease by 5%, but the elongation to fracture significantly improved by about 200%, in comparison with the unstrained samples, using a much shorter aging time. Transmission electron microscopy investigations showed that nano-sized alpha (α) particles homogeneously precipitated in the beta (β) matrix, and continuous α films formed along grain boundaries in the unstrained and aged samples. However, in the prestrained samples, the coarse stress induced martensite laths decomposed into α- and β-phases in the form of alternately arranged plates, which suppressed formation of the continuous grain boundary α films during aging. The hardness of the prestrained samples was lower than that of the unstrained samples after the same aging treatments. The enhancement of ductility can be mainly attributed to the suppression of grain boundary α films and the reduced hardness in prestrained samples.
Current-induced growth of P-rich phase at electroless nickel/Sn interface
Authors: Yang Qiliang , Shang Panju , Guo Jing D. , Liu Zhiquan , Shang Jian-Ku
Published: August 2009

The role of high current stressing during growth of the P-rich phase at the electroless Ni/Sn interface was examined by transmission electron microscopy. Prior to current stressing, two layers of Ni12P5, columnar Ni12P5 and noncolumnar Ni12P5, were formed after soldering. Upon electric stressing, the two layers of P-rich phase showed opposite growth patterns at the two opposing electrode interfaces. At the cathode, columnar growth of the P-rich phase was greatly enhanced while growth of the noncolumnar layer was inhibited. By contrast, the opposite was found at the anode where the current stressing promoted the noncolumnar growth but suppressed the growth of the columnar layer. Such a strong polarity effect resulted from directional electromigration of the key reaction species, nickel, to and from the interfacial reaction fronts. As a result of the difference in reaction mechanism, overall growth of the P-rich phase was much faster at the cathode during current stressing.
Observations of continuous tin whisker growth in NdSn3 intermetallic compound
Authors: Xian Ai-Ping , Liu Meng
Published: August 2009

In situ observation of tin whisker growth in NdSn3 compound was carried out by using an optical microscope (OM) and scanning electron microscopy (SEM). The growth rate of Sn-whisker from NdSn3 is shown to be rapid (approximately 8-15Å/s) during exposure to room ambience, and it is accompanied by formation of a new compound, Nd(OH)3, as was confirmed by x-ray diffraction. This reaction between the Sn-RE compound and trace water in room ambience has significant influence on whisker growth. There is an electron irradiation effect on whisker growth; that is, whiskers stopped growing after being observed in SEM. Therefore, it is suggested that OM be used rather than SEM to observe the continuous whisker growth. In discussion, the driving force per Sn atom for whisker growth is estimated as 1 × 1014 N in accordance with the whisker growth rate, and its apparent force originates from a chemical potential gradient between the released Sn atoms and the whisker.
Fabrication of high-strength transparent MgAl2O4 spinel polycrystals by optimizing spark-plasma-sintering conditions
Authors: Morita Koji , Kim Byung-Nam , Hiraga Keijiro , Yoshida Hidehiro
Published: August 2009

By optimizing the heating rate during spark-plasma-sintering (SPS) processing, a high-strength transparent spinel (MgAl2O4) can be successfully fabricated for only a 20-min soak at 1300 °C. For the heating rates of ≤10 °C/min, the spinel exhibits an excellent combination of in-line transmission (50–70%), four-point-bending strength (>400 MPa), and hardness (>15 GPa). The excellent optical and mechanical properties can be ascribed to the superimposed effects of the sub-micrograin size, fine-pore size, and low porosity, which are related closely to the heating rate during the SPS processing. The present study demonstrates that to attain a high-strength transparent spinel at low temperatures and short sintering times, the low-heating-rate SPS processing is more efficient compared with the high-heating-rate SPS processing.
Silver nanoparticles for printable electronics and biological applications
Authors: Balantrapu Krishna , Goia Dan V.
Published: August 2009

An environmentally friendly route to prepare stable concentrated aqueous dispersions of silver nanoparticles is described. It was found that Arabic gum, a well known stabilizing agent, can also rapidly and completely reduce Ag2O to metallic silver in alkaline solutions (pH > 12.0) and elevated temperature (65 °C). The average size of the silver nanoparticles could be tailored from 10 to 30 nm by varying the experimental conditions. By hydrolyzing either enzymatically or chemically the polysaccharide, it was possible to isolate dispersed silver nanoparticles suitable for both biological and printable electronics applications. For the latter purpose, concentrated dispersions of silver particles were prepared and used for depositing thin uniform layers, which could be sintered into conductive films at low temperatures.
The influence of drying temperature on the close packed structure of silanized monolayers deposited on indium tin oxide (ITO) substrates
Authors: D’Elia Stefano , Barna Valentin , Scaramuzza Nicola , Strangi Giuseppe , Bartolino Roberto
Published: August 2009

Molecular organization of self-assembled n-dimethyl-n-octadecyl-3-aminopropyltrimethoxysilychloride (DMOAP) layers on indium tin oxide (ITO) coated glass substrates was thoroughly investigated. The layer thickness for each deposition was determined by variable angle spectroscopic ellipsometry (VASE), while from static contact-angle measurements we deduced valuable information regarding the ordering of the molecular structures at the solid-air interface. In particular, the DMOAP thin film formation was studied for two different drying temperatures (85 °C and 120 °C). While at Tdrying = 85 °C we observed the formation of a molecular monolayer characterized by a close packed structure, at the higher temperature the DMOAP molecules “bend” at the substrate as they stack in relatively disordered clusters. A qualitative interpretation of this phenomenon is given, in good agreement both with the obtained experimental data and experimental investigation reported in the scientific literature. The observations regarding the DMOAP molecular level organization as a function of substrate temperature could bring essential information to the self assembly research community and also explain some important physical phenomena occurring at interfaces.
Pressure hysteresis in the TiMn1.5Vx-H2 (x = 0.1–0.5) system
Authors: Li Yongtao , Zheng Shiyou , Fang Fang , Zhang Hanping , Zhang Qingan , Sun Dalin
Published: August 2009

The structural characteristics of TiMn1.5Vx (x = 0.1–0.5) alloys and the hysteresis phenomenon in the TiMn1.5Vx-H2 system have been studied. The TiMn1.5Vx alloy consists mainly of the C14 Laves phase plus some of the BCC solid solution phase, depending on x. The lattice parameters of the C14 Laves phase increase slightly as x increases from 0.1 to 0.2 but are invariant with a further increase in x up to 0.3–0.5. The pressure-composition isotherms clearly show a pressure hysteresis in the TiMn1.5Vx-H2 system which decreases with an increase in the x value mainly due to the equilibrium pressure change for hydride formation. The free energy loss during hydride formation is related to not only the volume expansion, but also the elastic strain in the TiMn1.5Vx alloy itself, that is, prior to hydrogen absorption.
Evaluation of matrix strength in ultra-fine grained pure Al by nanoindentation
Authors: Zhang Ling , Ohmura Takahito , Emura Satoshi , Sekido Nobuaki , Yin Fuxing , Min Xiaohua , Tsuzaki Kaneaki
Published: August 2009

Nanoindentation measurements of the grain interiors of an ultra-fine grained (UFG) pure Al produced by equal channel angular pressing were taken to evaluate the contribution of the matrix strength. Specimens were subjected to 0, 1, 2, 4, and 8 passes at ambient temperature. The nanohardness of the deformed samples was always higher than that of the undeformed sample 0P in the range of the indentation depth that was investigated, suggesting a strengthening of the matrix in the UFG Al. The increase in hardness that was contributed by the matrix to the macroscopic scale hardness was significantly large in about 40% of the deformed samples. The microstructural characterization and the deformation response analysis with the pop-in event during indentation suggested that the strengthening of the matrix originated from dislocation strengthening and some other presumable factors in the grain interiors.
Improved wettability of Sn-based solder over the Cu60Zr30Ti10bulk metallic glass surface
Authors: Imai A. , Katayama M. , Maruyama S. , Nishikawa H. , Wada T. , Kimura H. , Fukuhara M. , Takemoto T. , Inoue A. , Matsumoto Y.
Published: August 2009

The wettability of Pb-free Sn-based solder over the Cu-based Cu60Zr30Ti10bulk metallic glass surface was investigated. We observed that the as-polished surface was nonwetting for the solder, which was due to the surface oxide layer of ZrOxformed in air. After complete removal of the oxide layer, a thin layer of Ag was deposited on the clean Cu60Zr30Ti10surface. The Ag-covered Cu60Zr30Ti10surface showed relatively high resistivity to the reoxidation even in air, and thus the wettability of the Cu60Zr30Ti10surface for the Sn-based solder was greatly improved.
Formation and properties of new Cu-based bulk glassy alloys with critical diameters up to 1.5 cm
Authors: Zhang Wei , Zhang Qingsheng , Qin Chunling , Inoue Akihisa
Published: August 2009

New Cu-based bulk glassy alloys (BGAs) with high glass-forming ability (GFA) were synthesized in a Cu-Zr-Al-Ag system. As the compositions of Cu-Zr-Al-Ag alloys with lower Ag and Al content shifted to the Cu-rich range, the supercooled liquid region, reduced glass transition temperature, and γ value increased, leading to the improvement of GFA. The best GFA is located around Cu47Zr45Al5Ag3, which is close to eutectic. Fully glassy samples with diameters up to 15 mm were fabricated by copper mold casting. These Cu-based BGAs exhibit excellent mechanical properties under compression. A large Young's modulus of 104–111 GPa, high fracture strength of 1905–1942 MPa, and distinct plastic strain of 0.002–0.011 were obtained. Additionally, the BGAs also show good corrosion resistance in 1 N H2SO4 solution.
Effects of ultraviolet radiation on ultra-low-dielectric constant thin film fracture properties
Authors: Smith Ryan Scott , Tsui Ting Y. , Ho Paul S.
Published: August 2009

The effects of ultraviolet (UV) radiation on ultra-low-kdielectric (ULK) thin film fracture toughness were studied. This work discusses both critical and subcritical crack growth behavior under different environments. The critical fracture toughness was measured as a function of applied phase angle by using the four-point bend flexure and mixed-mode double cantilever beam techniques. Results of critical fracture toughness obtained under different loading configurations and phase angles were found to increase with the UV treatment time. In contrast, mode I subcritical fracture toughness thresholds and the crack propagation velocity appeared to be insensitive to UV curing processes. This study revealed that subcritical fracture toughness values reduced with the moisture concentration in the environment.
Fabrication of ultrafine fibrous polytetrafluoroethylene porous membranes by electrospinning
Authors: Xiong Jie , Huo Pengfei , Ko Frank K.
Published: August 2009

Poly(vinyl alcohol) (PVA) and poly(tetrafluoroethylene) (PTFE) emulsion were blended with different mass concentrations and the blended spinning solutions were electrospun into composite nanofibers. The influence of the blend ratio of PVA to PTFE and electrospinning technical parameters on the morphology and diameter of the composite nanofibers were investigated. According to the result of thermogravimetric analyzer analysis, the composite membrane was sintered at 390 °C. The membranes were then characterized by differential scanning calorimetry, attenuated total reflection-Fourier transform infrared (ATR-FTIR), and scanning electron microscopy, respectively. The mechanical properties of the membranes before and after sintering were analyzed through tensile testing. The results show that the PTFE porous membranes could be electrospun effectively, thus demonstrating their potential application as filter media.
Dielectric properties and energy storage capability of antiferroelectric Pb0.92La0.08Zr0.95Ti0.05O3 film-on-foil capacitors
Authors: Ma Beihai , Kwon Do-Kyun , Narayanan Manoj , (Balu) Balachandran U.
Published: August 2009

Antiferroelectric (AFE) Pb0.92La0.08Zr0.95Ti0.05O3 (PLZT) films were grown on nickel foils with lanthanum nickel oxide buffer by chemical solution deposition. We observed field-induced AFE-to-ferroelectric (FE) phase transition. The electric field for the AFE-to-FE phase transition (EAF ≈ 270 kV/cm) and that for the reverse phase transition (EFA ≈ 230 kV/cm) were measured at room temperature on samples with PLZT films of ≈1-µm thickness. Relative permittivity of ≈560 and dielectric loss of <0.05 were measured near zero DC bias field. Hysteresis loop analysis showed that energy densities of ≈53 and 37 J/cm3 can be stored and recovered from the film-on-foil capacitors at 25 and 150 °C, respectively. Highly accelerated life tests were conducted. The projected mean time to failure is >5000 h when the capacitors are operated at room temperature with an applied field of ≈300 kV/cm.
Effect of nitrogen in the reaction atmosphere on the microstructure of carbon nanofibers grown by thermal chemical vapor deposition
Authors: Wu Ting-Yu , Tzeng Shinn-Shyong
Published: August 2009

Carbon nanofibers (CNFs) with different microstructures were synthesized by thermal chemical vapor deposition using different growth temperatures and methane/nitrogen gas mixtures. High-resolution transmission electron microscopy images revealed that bamboolike structure could be formed both by increasing the growth temperature and by increasing the nitrogen content in the reaction atmosphere at a lower growth temperature. Elemental analysis results indicated that no significant change in the nitrogen concentration was found regardless of the increase of nitrogen flow in the feed gas. The formation of bamboolike structure of CNFs and the effect of nitrogen gas on the microstructure change of CNFs were discussed.
Growth mechanism and magnetic properties for the out-of-plane–oriented Nd–Fe–B films
Authors: Yao Qi , Liu Wei , Cui W.B. , Yang F. , Zhao X.G. , Zhang Z.D.
Published: August 2009

The growth mechanism for the out-of-plane orientation of Nd–Fe–B films has been interpreted by the adparticle mobility during film growth, from the point view of the extended structure zone model. The growth mode changes sequentially from zone II to zone Ic, with the lowered thermally induced adparticle mobility on the surface as the film grows. As such, the whole Nd–Fe–B film evolves from [00l] out-of-plane orientation to more randomly out-of-plane alignment. With the growth of the out-of-plane–oriented Nd–Fe–B film, the correlation between the magnetic properties and the alignment evolution has been studied. The coercivity variation with the film growth is understood by analyzing the nucleation-dominant reversal processes for the out-of-plane–oriented Nd–Fe–B films.
Synthesis of ZnS nanorod arrays by an aqua-solution hydrothermal process on pulse-plating Zn nanocrystallines
Authors: Yu Wen , Fang Pengfei , Wang Shaojie
Published: August 2009

Large-scale, well-aligned, and oriented ZnS nanorod arrays were fabricated by a novel and original template-free hydrothermal method. The ZnS nanorods were grown on the pulse-plating Zn nanocrystallines along a certain Zn crystalline direction. It was found that reaction factors such as hydrothermal reaction time, zinc source, and sulfide source concentration in the precursor solution, the acid–base property of the precursor solution, and the substrate where ZnS nanorod arrays were grown greatly influence the morphology of the final products. The growth mechanism of ZnS nanorod arrays was also studied. Pulse-plating Zn nanocrystallines were found to be essential for the growth of ZnS nanorod arrays. These ZnS nanorod arrays could be theoretically fabricated on almost any raw base plate as long as Zn nanocrystallines could be pulse-plated on it. Therefore, the as-synthesized ZnS nanorod array might be one of the promising candidates for field-emission or sensitive nanomaterials in the future.
Thermal explosion reaction in the Ti–B4C system in air
Authors: Yang Y.F. , Wang H.Y. , Wang J.G. , Jiang Q.C.
Published: August 2009

The ignition and reaction processes of the thermal explosion reaction from the Ti–B4C system in air were studied. The thermal explosion reaction for the formation of TiC and TiB2 can be initiated at a relatively low temperature with the incorporation of air. Generally, the ignition process in air is suggested to be a chemical oven rather than gas transport, and the reaction process is proposed to be dissolution and precipitation.
Nanocrystalline Nd2–yGdyZr2O7 pyrochlore: Facile synthesis and electrical characterization
Authors: Mandal Balaji P. , Dutta Atanu , Deshpande S.K. , Basu R.N. , Tyagi Avesh K.
Published: August 2009

Three solid solutions of pyrochlores in the series Nd2-yearsGdyZr2O7 (y = 0.8, 1.0, 1.2) were synthesized by the gel combustion method using citric acid as fuel. This results in a soft agglomerate powder as verified by dynamic light scattering. The single-phase nature of the products has been confirmed by x-ray diffraction. The increase in full width at half-maxima in the Raman spectra with an increase in Gd3+ content indicates that disorder increases with Gd3+ content. The morphology and particle size of the products were investigated by transmission electron microscopy. Scanning electron microscopy study reveals that the sintered pellets have a density higher than 92% of theoretical densities. The total ionic conductivity measurements in the temperature range 375–800 °C show that with the increase of disorder (Gd3+ content) in the system the activation energy of conduction increases from 0.98 to 1.06 eV and the preexponential factor, which is proportional to the number of mobile species, also follow the same trend of increase. The total conductivity measured in reducing atmosphere shows no change in electrical conductivity, which verifies a negligible contribution of electronic contribution in this system.
Elastic modulus of low-k dielectric thin films measured by load-dependent contact-resonance atomic force microscopy
Authors: Stan Gheorghe , King Sean W. , Cook Robert F.
Published: August 2009

Correlated force and contact resonance versus displacement responses have been resolved using load-dependent contact-resonance atomic force microscopy (AFM) to determine the elastic modulus of low-k dielectric thin films. The measurements consisted of recording simultaneously both the deflection and resonance frequency shift of an AFM cantilever probe as the probe was gradually brought in and out of contact. As the applied forces were restricted to the range of adhesive forces, low-k dielectric films of elastic modulus varying from GPa to hundreds of GPa were measurable in this investigation. Over this elastic modulus range, the reliability of load-dependent contact-resonance AFM measurements was confirmed by comparing these results with those from picosecond laser acoustic measurements.
Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter
Authors: Kang Seung-Kyun , Kim Ju-Young , Kang Ingeun , Kwon Dongil
Published: August 2009

We introduce a novel method to correct for imperfect indenter geometry and frame compliance in instrumented indentation testing with a spherical indenter. Effective radii were measured directly from residual indentation marks at various contact depths (ratio of contact depth to indenter radius between 0.1 and 0.9) and were determined as a function of contact depth. Frame compliance was found to depend on contact depth especially at small indentation depths, which is successfully explained using the concept of an extended frame boundary. Improved representative stress-strain values as well as hardness and elastic modulus were obtained over the entire contact depth.
High-strength Al87Ni8La5 bulk alloy produced by spark plasma sintering of gas atomized powders
Authors: Scudino Sergio , Surreddi Kumar B. , Nguyen Hoang V. , Liu Gang , Gemming Thomas , Sakaliyska Mira , Kim Ji S. , Vierke Jens , Wollgarten Markus , Eckert Jurgen
Published: August 2009

In situ devitrification and consolidation of gas atomized Al87Ni8La5 glassy powders into highly dense bulk specimens was carried out by spark plasma sintering. Room temperature compression tests of the consolidated bulk material reveal remarkable mechanical properties, namely, high compression strength of 930 MPa combined with plastic strain exceeding 25%. These findings demonstrate that the combined devitrification and consolidation of glassy precursors by spark plasma sintering is a suitable method for the production of Al-based materials characterized by high strength and considerable plastic deformation.
Synthesis of the new RGaMnO5 (R = Ho, Er, Tm) oxides: Structural and magnetic features
Authors: Calle Cristina de la , Alonso Jose A. , Martínez-Lope Maria J. , García-Hernández Mar , Fernández-Díaz M.T.
Published: August 2009

Polycrystalline HoGaMnO5, ErGaMnO5, and TmGaMnO5 oxides have been first prepared by soft chemistry procedures followed by high oxygen pressure treatments, to stabilize Mn4+ cations. Their crystal structures and magnetic behavior have been studied at room temperature and 5 K by neutron powder diffraction (NPD) data in complement with magnetization measurements. RGaMnO5 are orthorhombic, Pbam space group, and their crystal structures contain infinite chains of edge-sharing Mn4+O6 octahedra, interconnected by pyramidal Ga3+O5 and RO8 units. For R = Ho, a = 7.2810(4), b = 8.4526(4), and c = 5.6668(3) Å; for R = Er, a = 7.2575(3), b = 8.4357(3), and c = 5.6613(2) Å; and for R = Tm, a = 7.2438(3), b = 8.4124(3), and c = 5.6509(2) Å, at room temperature. Above 300 K the reciprocal magnetic susceptibility follows a Curie-Weiss law. In the paramagnetic region, a positive Weiss constant suggests the presence of ferromagnetic interactions, which have been investigated by low-temperature NPD for R = Er, Tm. The 5 K patterns show a detectable long-range magnetic ordering over the Mn and R positions, ferromagnetically aligned along the x-direction.
Interaction of O and H Atoms with low-k SiOCH films pretreated in He plasma
Authors: Braginsky O. V. , Kovalev A. S. , Lopaev D. V. , Mankelevich Y. M. , Malykhin E. M. , Proshina O. V. , Rakhimova T. V. , Rakhimov A. T. , Vasilieva A. N. , Voloshin D. G. , Zyryanov S. M. , Baklanov Mikhail R.
Published: September 2009

The effect of He plasma pretreatment on interaction of O and H atoms with SiCOH low-k materials is studied using a special experimental system designed for this purpose. The experimental system allowed separate study of the effects of He plasma, VUV light and He 21S0 metastable atoms. It is shown that the carbon depletion by oxygen atoms can be significantly reduced by He plasma pretreatment. Considerable increase of CH and CH2-CH2 groups in the surface area of low-k films is observed when the films were exposed to VUV light and metastable atoms generated by He plasma. FTIR and ellipsometry showed formation of densified surface layer. This carbon rich densified surface layer decreases damage of low-k film when it is exposed in O2 plasma. The impact of H atoms on low-K surface noticeably differs from O atoms effect. The H atoms saturate all unbounded remaining carbon bonds thereby promoting improvement of SiOCH structure.
Mechanical Scaling Trends and Methods to Improve Reliability of Packaged Interconnect Structures
Authors: Lane Michael , Roush Abigail , Callahan Stephen E.
Published: September 2009

Low dielectric constant (low-k) materials are currently being incorporated into advanced microelectronic devices to improve or maintain performance. As the dielectric constant is reduced, so are its mechanical properties. These reduced properties have recently been related to chip-package interaction (CPI) failures. Significant effort has focused on eliminating CPI failures through engineering of copper crackstop structures. However, published data suggests that crackstop engineering needs to occur at each technology node to ensure CPI reliability. In this study, the focus is on repairing interfacial delaminations with chemistry specific coupling agents rather than attempting to stop them with a specially designed crackstop structure. Critical adhesion values and corrosion resistance of the repaired interfaces are compared to the original interface. The application of the repair chemistry in an integrated structure is discussed along with the potential impact on reliability.
Synthesis of Vertically Aligned Multi-Walled Carbon Nanotubes on Copper Substrates for Applications as Thermal Interface Materials
Authors: LIN WEI , Wong Chingping
Published: September 2009

Vertically aligned carbon nanotubes (VACNTs) grown on bulk copper substrate are of great importance for CNT real-life applications as thermal interface materials in microelectronic packaging. However, their reproducible synthesis has been a great challenge so far. In this study, by introducing a well-controlled conformal Al2O3 support layer on the bulk copper substrate by atomic layer deposition (ALD) prior to the deposition of the iron catalyst layer, we reproducibly synthesize VACNTs of good alignment and high quality on the copper substrate, using a conventional thermal chemical vapor deposition process. The alignment and the quality are characterized by scanning electronic microscopy and Raman spectroscopy, respectively. The roles of the conformal Al2O3 support layer are discussed. A kinetics-controlled growth mechanism is shown. This progress provides a viable VACNT commercial application for thermal management, on the basis of which, we show a recent progress on a state-of-art Si/VACNT/Cu assembling process, named “chemical anchoring”. The high quality of the VACNTs on the copper growth substrate and the covalent bonding formed between the VACNTs and the silicon mating substrate greatly reduces the thermal resistance of the VACNT-mediated thermal interface.
3D Thermal-Fluid and Stress Analysis for Single Chip SiC Power Sub-Modules
Authors: Tsao Bang-Hung , Sondergelt Katie , Lawson Jacob , Scofield James , Elston Levi
Published: September 2009

A three dimensional thermal-fluid and stress model of a single chip SiC power sub-module was generated using ANSYS in order to determine the maximum temperature and deformation under various conditions. The effects of heat flux, working fluid temperature and differential pressure on temperature and thermal stress contours were of particular concern. Steady state analysis with water as the working fluid, a simulated heat flux of 11.12×104 W/m2, an interface coupling film coefficient of either 30 or 200 W/m2-K between the cooling plate and fluid, and ambient film coefficients from 6 W/m2-K to 300 W/m2-K, predicts maximum device junction temperatures between 374 and 316 K, and corresponding deformations from .0351% to .0293%. Under the same boundary and loading conditions, but with air as the working fluid, the deformations reached .0405% to .0296%, with temperatures between 427 and 316 K. Transient analysis also showed junction temperatures in the predicted range and determined the time to reach steady state to be between 150 and 2500 seconds depending on the boundary conditions. Experiments were conducted in order to validate ANSYS results.
Thermal Transport Properties of Nanostructures Immobilized Substrates
Authors: Richardson Hugh H. , Thomas Alyssa C. , Carlson Michael T. , Govorov Alexander O.
Published: September 2009

We characterize a temperature sensor made from Erbium ions embedded in an amorphous AlGaN matrix that is accessed remotely by measuring the relative intensities from photoluminescence peaks of Er3+. We use this sensor to measure the nanoscale temperature around an optically excited single gold nanoparticle that has been immobilized on the AlGaN substrate. The maximum temperature increase measured experimentally is 8.3 K. The temperature measurement is diffraction limited by our microscope to 490 nm. This temperature corresponds theoretically to a maximum local temperature increase of 22 K. A straight-forward analysis using energy balance gives the thermal conductivity of the amorphous AlGaN substrate as 4.5 W/m-K.
New Version of Laser Device Materials for Developing Diffraction Beam Modulators; Novel Nano -periodic Structures
Authors: Choi Kyung , Shea Kenneth
Published: September 2009

Cro/CrOx-doped hybrid glasses are designed to develop novel laser device materials by inserting alkylene spacers between inorganic oxides. In TEM images, morphology of the organically modified hybrid glasses reveals highly arranged nano-periodic patterns. The nano-patterns observed from the hybrid glass based on alkylene-bridged xerogel are sustained over substantial domains and appears to arise from modified glassy lattice fringes. In electron diffraction pattern, it also shows the circled diffraction patterns arise from Cro/CrOx. In laser experiments, the hybrid glass shows a new optical property, which generates a huge acoustic wave; the diffraction efficiency (45 %) of the modified glass is higher than that of methanol (25 %); it means that the compressibility of the solid type of glass is as effective as the liquid. The hybrid glass shows a new optical property that hitherto hasn’t been found and could be useful for developing diffraction beam modulators.
HWCVD-grown Silicon Nanocrystals : A study of the effect of annealing on structures evolved with varying growth rates
Authors: Mahajan Prantik , Patil Tarkeshwar C , Chakrabarti Subhananda
Published: September 2009

In this work, we investigated the evolution of Silicon Nanostructures with progressive annealing under different growth conditions. A structure - SixNy/a-Si/SixNy/a-Si - was grown on n-type <100> Silicon substrate using Hot Wire CVD (HWCVD) deposition technique. We report here the growth of Silicon Nanostructures by HWCVD technique with a special focus on the nature and morphology of the nanostructures with variation in growth rate and post-annealing temperature. AFM studies revealed promising results hinting at the presence of Silicon Nanostructures. With progressive annealing the morphology of the Nanostructures changed from particles to sharp pillars particularly in one of the samples elaborated in the text below. FWHM from the Confocal Raman data at room temperature was found to be 3.19 cm−1 with the a-Si peak at 520 cm−1.
Photoconductivity Dependence on the Background Oxygen Pressure in Nanostructured ZnO UV Sensor
Authors: Hullavarad Nilima V , Hullavarad Shiva S
Published: September 2009

The present work describes the photoconductivity dependence on ZnO nanostructure UV sensor. ZnO nanostructures were synthesized by direct vapor phase (DVP) technique. ZnO nanowires are of dimensions 30-65 nm in diameter and 5 μm in length. The role of oxygen in deciding the opto-electronic properties of nanostructured ZnO UV sensors was studied.
Miniaturization of Immunoassays Using Optical Detection with Integrated Amorphous Silicon Photodiodes
Authors: Pereira Ana Teresa , Chu Virginia , Prazeres Duarte M. F. , Conde Joao P
Published: September 2009

Immunoassays are currently the main analytical technique for quantification of a wide range of analytes of clinical, medical, biotechnological, and environmental significance with high sensitivity and specificity. Miniaturization of immunoassays is achieved using microfluidics coupled with integrated optical detection of the antibody-antigen molecular recognition reaction using thin-film amorphous silicon (a-Si:H) photodiodes. The detection system used consists of an a-Si:H photodiode aligned with a polydimethylsiloxane (PDMS) microchannel. An enzymatic reaction taking place in the microchannel yields a product which is a light-absorbent molecule and hence can be optically detected by the integrated photodiode. Specific antigen-antibody reaction was detected and distinguished from the non-specific reaction.
Screen-Grid Field Effect Transistor for sensing Bio-Molecules
Authors: Eng Kwee Guan , Fobelets Kristel , Velazquez-Perez Enrique
Published: September 2009

A novel field effect transistor, based on the Screen Grid Field Effect Transistor concept, is proposed with an integrated Coulter Counter pore for amplification of the sensing signal. 3D TCAD simulations are performed on the use of the Coulter Counter Field Effect Transistor (CCFET) to detect the Influenza A virus. The gate of the transistor is the pore through which the bioparticles pass. This passage causes a change in the electrostatic conditions of the gate and thus changes the source-drain current, similar to ISFET operation. The structure of the CC-FET is optimised for bio-sensing and multi-particle passage through the gate hole is simulated. TCAD
results show that the CC-FET is capable of multi-particle and particle size detection.
Learners Need Purposeful and Systematic Instruction
Authors: Ross Donna , Frey Nancy
Published: September 2009

The authors explain an instructional framework that gradually releases responsibility from teachers to learners. The article illustrates with an example of real teaching from an arts classroom, and multimedia supplements (http:www.reading.orgGeneralPublicationsJournalsJAALSupplementalContentjaalJAAL‐53‐1‐Rosssupp‐1.aspx) further demonstrate what modeling and gradual release of responsibility look like with teachers and teens.

تلخيص البحث: يوفر هذا المخطوط القراء بمعلومات عن التعليم في إطار التنازل التدريجي عن المسؤولية. ويشرح المؤلفون النموذج التعليمي وثمة يضربون مثالاً لتعليم حقيقي من صف فنون.

本文是关于以渐进式责任解除为理论框架的教学方法。本文作者解释这教学方法的模式，及提供一个文科课堂的真实教学示例。

Cet article apporte aux lecteurs des informations sur l'enseignement dans un cadre comportant une responsabilité progressive. Les auteurs présentent leur modèle pédagogique puis apportent un exemple concret d'enseignement dans une classe d'enseignement des arts.

Читатели получат информацию о методах обучения, основанных на постепенном перераспределении ответственности между учителем и учащимися – в пользу последних. Авторы объясняют учебную модель и приводят в пример работу учителя‐предметника на уроках художественного творчества и истории искусств.

Este manuscrito presenta a los lectores con información sobre la enseñanza basada en el marco de liberación gradual de responsabilidad. Los autores explican el modelo de instrucción y proveen un ejemplo real en una clase de arte.
A new species representing the oldest aphid (Hemiptera, Aphidomorpha) from the Middle Triassic of China
Authors: Hong Youchong , Zhang Zhijun , Guo Xinrong , Heie O. E.
Published: August 2009

A new aphid species,Dracaphis angustata, has been found in China from the Middle Triassic. It is especially informative because its whole body is preserved except for the distal part of the antennae and part of the legs. Only wings of three other aphid species of Triassic age have previously been found:Triassoaphis cubitus, described by Evans (1956) from Australia and placed in its own family, Triassoaphididae Heie, 1999;Creaphis theodora, described by Shcherbakov and Wegierek (1991) from Central Asia and placed in its own family, Creaphididae; andCoccavus supercubitus, described by Shcherbakov (2007) from Kyrgyzstan and placed in Naibiidae together withNaibiafrom the Lower Tertiary. The new species described below must be placed in its own family Dracaphididae because it possesses a combination of characters unknown in any other aphid clade.
New skeletal material ofAndrewsiphiusandKutchicetus,two Eocene cetaceans from India
Authors: Thewissen J. G. M. , Bajpap Sunil
Published: August 2009

The Eocene cetacean generaAndrewsiphiusandKutchicetusare systematically revised, their anatomy described, and their phylogenetic position analyzed. Each genus contains a single species,A. sloaniandK minimus,and both are known only from the middle Eocene of the Indian Subcontinent.AndrewsiphiusandKutchicetusdiffer in a number of respects, the most important dental difference being that P2, P3, p2, and p3 are double-rooted inAndrewsiphiusand single-rooted inKutchicetus.Lower molars are separated by diastemata inKutchicetus,but not inAndrewsiphius.Postcranially,Andrewsiphiushas caudal vertebrae that are far more robust than those ofKutchicetus.

We propose the new clade Andrewsiphiinae for these two genera, based on their unique characters: the extremely slender jaw, fused mandibular symphysis, narrow palate and rostrum, and lower molars that have a low crown with three cusps lined up rostro-caudally. A phylogenetic analysis indicates that andrewsiphiines are either a subfamily of Remingtonocetidae or an independent branch on the Eocene cetacean lineage. Interpreting conservatively, we classify them as remingtonocetids. Andrewsiphiines have a long, robust, dorso-ventrally flattened tail and short limbs, suggesting that they swam using dorsoventral undulation of the tail.