bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Effect of Buoyancy on Flow and Heat Transfer of Supercritical Pressure Water in Horizontal Pipes
Authors: Yu Shuiqing , Li Huixiong , Lei Xianliang , Zhang Yifan , Chen Tingkuan
Published: March 2012

The present paper is devoted to clarify the effect of buoyancy on the flow and heat transfer of supercritical pressure water flowing in horizontal pipes at supercritical pressures. A series of experiments have been designed and carried out in Xi’an Jiaotong University, Xi’an, China to obtain data in relation to flow and heat transfer of supercritical pressure water in pipes with different arrangements. The experimental parameters are as follows: pressures ranging from 23 to 28MPa, heat flux being up to 600 kW/m2, and the fluid mass fluxes being in the range from 100 to 1000kg/(m2s). In this study, distributions of the local wall temperatures and the local heat transfer coefficients around the circumference of the tube are measured at different cross-sections along the flowing direction. On the basis of the experimental data obtained in the study, some criteria available in open literatures, including Gr/Re2.7, Gr/Re2, and Grq/Grth, are employed to estimate the magnitude of buoyancy and the effect of buoyancy on the flow and heat transfer behavior of the supercritical fluid. It is showed that buoyancy is of particular importance for horizontal flows, but play significantly different role in different regions having different characteristics of the specific heat capacity. Strong buoyancy effect exists in the large specific heat region, but in the enthalpy region which is far away from the LSHR, the discrepancy between the temperature of the top wall and that of the bottom wall is small, indicating that the buoyancy effect can be negligible. Based on the present study, it was found that the criteria Grq/Grth is better than others in terms of the capability of evaluating the effect of the buoyancy on the flow and heat transfer of supercritical water.
Experimental Research on Performance of Heat Transfer and Pressure Drop for Primary Surface Recuperator With Mini Channels
Authors: Ma Hugen , Gao Hui , Tu Wenjing
Published: March 2012

Based on the single blow technique, experimental research was conducted for the performance of heat transfer and flow drop for six test cores with cross corrugated (CC) or corrugated undulated (CU) primary surfaces for different geometries. After the mathematical model was established for heat transfer under the condition of single blow, a matching numerical solution was obtained for different NTU. The correlations of hear transfer factor j and friction factor f were obtained for three types of cross corrugated primary surfaces (crossed angle 45∼75°) with a range of Re = 120∼800 and three types of corrugated undulated primary surfaces (crossed angle 52.5∼67.5°) with a range of Re = 200∼1200. Hydraulic diameters of all heat transfer surfaces are from 1.2∼1.48mm. Analysis on the flow and heat transfer for cross corrugated and corrugated undulated primary surfaces was made based on the comprehensive evaluating factor j/f. The experimental results were compared to references with good consistency. The regressive errors of correlations were less than 16%.
Investigation on Removal of NOx and SO2 From Flue Gas by Combined Ozone With Absorption and By-Product Treatment
Authors: Zhang X. , Wang Z. H. , Zhu Y. Q. , Zhou Z. J. , Zhou J. H. , Cen K. F.
Published: March 2012

The combination of ozone with washing tower and an absorption products recovery system was utilized for removal of NOx and SO2 from flue gas. In our previous studies, more than 90% NO can be oxidized by ozone. In this study, three kinds of absorbents, Na2SO3, CaSO3 and Ca(OH)2, were evaluated for simultaneous absorption of NO2 and SO2 in the wet scrubbing. It was found that NO2 absorption efficiency was increasing with S(IV). Effect of different concentration of CaSO3 on NO2 absorption was investigated. Results show that nearly 70% NO2 can be absorbed in calcium sulfite slurry. Furthermore, NO2 absorption efficiency is increasing to 85% in the sulfite with assistant of MnSO4. In the meantime, the absorption efficiency of SO2 is always nearly 100%. A new system is built for recycling NO2 absorption products and purifying the waste water, which has the advantages of low investment and operating cost.
Research on the Burnout of Fujian Anthracite in CFB Boiler
Authors: He H. Z. , Zhuang H. H. , Luo Z. Y. , Cen K. F.
Published: March 2012

Coal property, boiler structural and designing parameters, running parameters of boiler are the main factors which influence the burnout of Fujian anthracite during combustion in CFB boiler. These coal properties and combustion characteristics such as the compact inner structure of particle, the poor combustion reactivity, and the strong thermal fragmentation tendency are the main reason that cause the Fujian anthracite difficult to burnout in CFB boiler. And these operating parameter such as the combustion temperature, the particle size distribution of feeding coal, the flow velocity of flue gas in furnace, the fly ash reburning, the excess air coefficient and the secondary air ratio have also an strong effect on its burnout. By means of improving the boiler structure and designing parameter such as rising the height of furnace, layout of refractory belt, choosing low-medium circulation ratio, employing high separation efficiency cyclone, ect, can also promote the burnout of Fujian anthracite when it combustion in CFB boiler. For those small-medium capacity CFB boiler (capacity ≤ 75 t/h) burning Fujian anthracite, due to its limited height of furnace, it is good to improve the burnout of Fujian anthracite by adjusting the operation parameter of boiler such as employing the mid-coarse size particle in feeding coal, properly rising the excess air coefficient and the secondary air ratio, intensifying the perturbation and penetration capability of secondary air in furnace, increasing the combustion temperature, and reburning the fly ash. In order to get a good burnout result, the running temperature of boiler should be risen to about 1000 °C, and the excess air coefficient is supposed to maintain in 1.25–1.30.
Solver Convergence of IGFC Process Simulation
Authors: Kurata Osamu , Nomura Risa , Iki Norihiko , Kawabata Masako , Tsutsumi Atsushi , Furutani Hirohide
Published: March 2012

Integrated Coal Gasification Fuel Cell Combined Cycle (IGFC) is expected to be the most efficient power generation system in coal fired power generation systems [1,2]. We have been analyzing the processes of Advanced IGFC (A-IGFC) [3] which is expected to be realized in 2040. The Advanced IGFC (A-IGFC) system can reduce the exergy loss resulting from combustion, and its ‘exergy recuperation’ [4] is appealing. The waste heat exhausted from the fuel cells is recycled to the gasifier for steam reforming in an endothermic reaction with a low exergy loss and a high cold gas efficiency. Our current study focuses on the optimization of the unit configurations of the A-IGFC including gasifier, compressor, solid oxide fuel cell (SOFC), combustor, gas turbine, heat recovery steam generator (HRSG), and steam turbine. The process simulator HYSYS®.Plant (Aspen technology Inc.) is employed in order to express the gasifier, the SOFC and the other units. The process of reforming with steam means recycled steam stream in the HYSYS® model. In the previous study [3] we found that many recycled material streams and recycled steam in the AIGFC process prevent convergence of solver. It is shown that comparison of simulation program, a trial analysis of the AIGFC process using HYSYS.Plant and the problems about convergence of solver.
A Simple Performance Test for Evaluating End Hose Support Straps for Railroad Freight Cars
Authors: Liu Z. , Hua L.
Published: March 2012

A study has been performed to simulate the impact experienced on hose support straps during end hose separations on railroad freight cars. Analysis and comparison of test results of different hose straps show that the elasticity of the hose strap determines the reaction force generated by a certain impact. Under the same impact, a stiffer hose strap sustains a larger reaction force. Unlike the current requirement of AAR S-4006, the relation between the elasticity of the hose strap and its reaction force is not linear. Additionally, for a certain impact, the reaction force of the hose strap is only related to its mechanical properties, which reflects the real application. This study concludes that a simple drop test is adequate as an alternative method for performance testing of hose straps.
Gap Junctions Compensate for Sublinear Dendritic Integration in an Inhibitory Network
Authors: Vervaeke Koen , Lőrincz Andrea , Nusser Zoltan , Silver R. Angus
Published: March 2012

Spreading the Excitation

Inhibitory interneurons balance network excitation, control spike-time precision of principal neurons, and control synchrony within and across brain regions.

Vervaeke
et al.

(p.
1624
, published online 8 March) combined electrophysiology, immunohistology, and numerical simulation to investigate the properties of Golgi cells, the main inhibitory interneurons in the input layer of the cerebellar cortex. The dendrites of these neurons were truly passive and acted as linear cables. Gap junctions were distributed nonuniformly on the Golgi cell surface, with a higher density on distal dendrites. Thus, gap junction-mediated lateral excitation preferentially enhanced the distal inputs, enabling distal synapses to drive network activity more effectively.
Mapping the Core of the
Arabidopsis
Circadian Clock Defines the Network Structure of the Oscillator
Authors: Huang W. , Pérez-García P. , Pokhilko A. , Millar A. J. , Antoshechkin I. , Riechmann J. L. , Mas P.
Published: March 2012

Tic TOC1 Plant Clock

The molecular clocks intertwined with cellular physiology regulate daily cycles. In plants, these circadian rhythms affect processes as diverse as carbon metabolism and leaf orientation.

Huang
et al.

(p.
75
, published online 8 March) have now analyzed the interactions driven by a key element of the circadian clock in plants, TOC1 (“TIMING OF CAB EXPRESSION 1”). TOC1 helps to coordinate responses of the morning and evening cycles, functioning to repress activity of other clock components.
Whole-Genome Sequence of Wolbachia Strain
w
AlbB, an Endosymbiont of Tiger Mosquito Vector Aedes albopictus
Authors: Mavingui Patrick , Valiente Moro Claire , Tran-Van Van , Wisniewski-Dyé Florence , Raquin Vincent , Minard Guillaume , Tran Florence-Hélène , Voronin Denis , Rouy Zoé , Bustos Patricia , Lozano Luis , Barbe Valérie , González Víctor
Published: March 2012

Although bacteria of the genus
Wolbachia
induced significant extended phenotypes to infected hosts, most molecular mechanisms involved are still unknown. To gain insight into the bacterial genetic determinants, we sequenced the whole genome of
Wolbachia w
AlbB strain, a commensal obligate intracellular of the tiger mosquito
Aedes albopictus
.
Complete Genome Sequence of Klebsiella pneumoniae subsp. pneumoniae HS11286, a Multidrug-Resistant Strain Isolated from Human Sputum
Authors: Liu Pinglei , Li Peng , Jiang Xiaofei , Bi Dexi , Xie Yingzhou , Tai Cui , Deng Zixin , Rajakumar Kumar , Ou Hong-Yu
Published: March 2012

Klebsiella pneumoniae
is an important pathogen commonly associated with opportunistic infections. Here we report the genome sequence of a strain, HS11286, isolated from human sputum in 2011 in Shanghai, China. It contains one chromosome (5.3 Mb), three multidrug resistance plasmids (∼110 kb), including a carbapenemase producer, and three small plasmids (∼3 kb).
The Complete Genome of Bacillus amyloliquefaciens subsp.
plantarum
CAU B946 Contains a Gene Cluster for Nonribosomal Synthesis of Iturin A
Authors: Blom Jochen , Rueckert Christian , Niu Ben , Wang Qi , Borriss Rainer
Published: March 2012

The genome of the rhizobacterium
Bacillus amyloliquefaciens
subsp.
plantarum
CAU B946 was 4.02 Mb in size and harbored 3,823 genes (coding sequences [CDS]). Nine giant gene clusters were dedicated to nonribosomal synthesis of antimicrobial compounds. Remarkably, strain CAU B946 possessed a gene cluster involved in synthesis of iturin A.
Complete Genome Sequence of the Dairy Isolate Streptococcus macedonicus ACA-DC 198
Authors: Papadimitriou Konstantinos , Ferreira Stéphanie , Papandreou Nikolaos C. , Mavrogonatou Eleni , Supply Philip , Pot Bruno , Tsakalidou Effie
Published: March 2012

The species
Streptococcus macedonicus
is associated with the food environment, especially with fermented dairy products. Here we present the complete 2.1-Mb genome sequence of strain ACA-DC 198, which was isolated from naturally fermented Greek kasseri cheese.
First malaria infections in a cohort of infants in Benin: biological, environmental and genetic determinants. Description of the study site, population methods and preliminary results
Authors: Le Port Agnès , Cottrell Gilles , Martin-Prevel Yves , Migot-Nabias Florence , Cot Michel , Garcia André
Published: March 2012

Objectives

Malaria infection of the placenta during pregnancy was found to be associated with infant susceptibility to malaria. Other factors such as the intensity of malaria transmission and the nutritional status of the child might also play a role, which has not been adequately taken into account in previous studies. The aim of this study was to assess precisely the parts played by environmental, nutritional and biological determinants in first malaria infections, with a special interest in the role of placental infection. The objective of this paper is not to present final results but to outline the rationale of the study, to describe the methods used and to report baseline data.

Design

A cohort of infants followed with a parasitological (symptomatic and asymptomatic parasitaemia) and nutritional follow-up from birth to 18 months. Ecological, entomological and behavioural data were collected along the duration of the study.

Setting

A rural area in Benin with two seasonal peaks in malaria transmission.

Participants

656 infants of women willing to participate in the study, giving birth in one of the three maternity clinics and living in one of the nine villages of the study area.

Primary Outcome Measures

The time and frequency of first malaria parasitaemias in infants, according toPlasmodium falciparuminfection of the placenta.

Results

11% of mothers had a malaria-infected placenta at delivery. Mosquito catches made every 6 weeks in the area showed an average annualP falciparumentomological inoculation rate of 15.5, with important time and space variations depending on villages. Similarly, the distribution of rainfalls, maximal during the two rainy seasons, was heterogeneous over the area.

Conclusions

Considering the multidisciplinary approach of all factors potentially influencing the malaria status of newborn babies, this study should bring evidence on the implication of placental malaria in the occurrence of first malaria infections in infants.
A survey of early health effects of the Eyjafjallajökull 2010 eruption in Iceland: a population-based study
Authors: Carlsen Hanne Krage , Gislason Thorarinn , Benediktsdottir Bryndis , Kolbeinsson Thorir Bjorn , Hauksdottir Arna , Thorsteinsson Throstur , Briem Haraldur
Published: March 2012

Objective

To estimate physical and mental health effects of the Eyjafjallajökull volcanic eruption on nearby residents.

Design

Cross-sectional study.

Setting

The Icelandic volcano Eyjafjallajökull erupted on 14 April 2010. The eruption lasted for about 6 weeks and was explosive, ejecting some 8 million tons of fine particles into the atmosphere. Due to prevailing winds, the ash spread mostly to the south and south-east, first over the rural region to the south, later over the Atlantic Ocean and Europe, closing European air space for several days.

Participants

Residents (n=207) of the most ash-exposed rural area south and east of the volcano.

Methods

The study period was from 31 May to 11 June 2010. Participants were examined by a physician. To ascertain respiratory health, standardised spirometry was performed before and after the use of a bronchodilator. All adult participants answered questionnaires about mental and physical health, their children's health and the use of protective equipment.

Results

Every other adult participant reported irritation in eyes and upper airway when exposed to volcanic ash. Adults (n=26) and children (n=5) with pre-existing asthma frequently reported worsening of their symptoms. No serious health problems requiring hospitalisation could be attributed to the eruption. The majority of the participants reported no abnormal physical or mental symptoms to the examining physician. Compared to an age- and gender-matched reference group, the ash-exposed participants reported lower smoking rates and were less likely to have ventilation impairment. Less than 10% of the participants reported symptoms of stress, anxiety or depression.

Conclusions

Short-term ash exposure was associated with upper airway irritation symptoms and exacerbation of pre-existing asthma but did not contribute to serious health problems. The exposure did not impair respiratory function compared to controls. Outdoor use of protective glasses and face masks was considered protective against irritation in eyes and upper airway.
Will more restrictive indications decrease rates of urinary catheterisation? An historical comparative study
Authors: Shimoni Zvi , Rodrig Joseph , Kamma Nama , Froom Paul
Published: March 2012

Objectives

To determine if more restrictive indications for urinary catheterisation reinforced by daily chart review will lower catheterisation rates.

Design

An historical comparative observational study.

Setting

An internal medicine department in a regional hospital in Israel.

Participants

The authors compared 882 patients hospitalised after a change in policy to an historical cohort of 690 hospitalised patients. Exclusions included patients less than age 30 and those with bladder outlet obstruction.

Intervention

Emergency and internal medicine department physicians received instruction on a more restricted urinary catheterisation policy. During daily chart rounds, admissions were discussed with an emphasis on the appropriateness of all new urinary catheter insertions.

Main outcome measures

The primary outcome measure was catheterisation rate by admission diagnosis. Secondary outcome measures were the need for post-admission in hospital catheterisations and the rate of indwelling catheters 14 or more days after discharge.

Results

There was a reduction in catheterisation rate in patients with congestive heart failure from 30/106 (29.3%) to 3/107 (2.8%) (p<0.001), in patients with an admission diagnosis of fever unable to provide a urine sample for culture from 35/132 (26.5%) to 12/153 (7.8%) (p<0.001) and in patients admitted for palliative care from 51.7% (15/29) to 12.0% (3/25) (p=0.002). The overall rate of catheterisation decreased from 17.5% (121/690) to 6.6% (58/882) (p<0.001). There was only one indicated catheterisation after admission due to the change in policy, and the proportion of patients discharged with catheters decreased.

Conclusion

The use of more restrictive indications for urinary catheterisation along with daily chart rounds can reduce the rate of urinary catheterisation in an internal medicine department without adverse consequences.
Familial factors and child characteristics as predictors of injuries in toddlers: a prospective cohort study: Table 1
Authors: Myhre Mia Cathrine , Thoresen Siri , Grøgaard Jens Bernard , Dyb Grete
Published: March 2012

Objective

To identify family and child characteristics that put toddlers at risk of injuries.

Design

A prospective cohort study.

Setting

This study was based on the Norwegian Mother and Child Cohort Study, conducted by the Norwegian Institute of Public Health.

Participants

The study sample consisted of 26 087 children and their mothers.

Outcome measures

Family and child characteristics measured before or at 18 months of age were investigated as potential predictors of hospital-attended injuries that occurred between 18 and 36 months of age.

Results

In the multivariable analysis, younger maternal age (OR 0.93, 95% CI 0.86 to 1.00), financial problems (OR 1.18, 95% CI 1.01 to 1.39), maternal mental distress (OR 1.09, 95% CI 1.03 to 1.16), having older siblings (OR 1.22, 95% CI 1.08 to 1.39), increased gestational age at birth (OR 1.04, 95% CI 1.00 to 1.07) and male gender (OR 1.26, 95% CI 1.11 to 1.42) were risk factors for hospital-attended injuries. Children with impaired gross motor development had a decreased risk of injury (OR 0.65, 95% CI 0.42 to 0.99), whereas those with impaired fine motor development had an increased risk (OR 1.55, 95% CI 1.22 to 1.97). Shyness was a protective factor (OR 0.92, 95% CI 0.86 to 0.98). Children with three reported attention problems had a slightly increased risk of hospital-attended injuries (OR 1.33, 95% CI 1.02 to 1.72; p=0.035); otherwise, behaviour was not a significant risk factor.

Conclusions

This study demonstrated that a wide variety of factors were in play as predictors of injuries in young children. Both child-related factors (gender, gestational age at birth, child motor development, shyness and attention) and familial factors (having older siblings, maternal age, financial difficulties and maternal mental health problems) were associated with injuries in toddlers.
Comparison of overlapping (OP) and adjacent thumb positions (AP) for cardiac compressions using the encircling method in infants
Authors: Lim Jung Soo , Cho YongCheol , Ryu Seung , Lee Jin Woong , Kim SeungWhan , Yoo In-Sool , You YeonHo , Lee Byung Kook , Min Jin Hong , Jeong Won Joon
Published: March 2012

Objectives

The aim of this manikin study was to compare the efficiency between overlapping (OP) and adjacent thumb positions (AP) for cardiac compressions using the encircling method in infants.

Methods

The study conducted from December 2010 to August 2011 involved 48 volunteers who were students in the emergency medical technician course. The authors let volunteers practice OP and AP as a crossover design. The authors monitored the simulated mean arterial pressure (MAP) generated during a 5-min chest compression. The fatigue level of the volunteers after the chest compression was evaluated with the Likert scale.

Results

There were no significant differences in MAP between the dominant hand and the non-dominant hand as the lower thumb of OP. Significant differences were observed in simulated systolic blood pressure, MAP and simulated pulse pressure between OP and AP at 1, 2, 3, 4 and 5 min. There were no significant differences among the changes in heart rate, respiratory rate and end-tidal CO2during a 5-min chest compression by OP and AP. The Likert scale scores (1 no fatigue to 5= extreme fatigue) during the 5-min chest compressions were higher in AP than in OP at 2, 3 and 5 min.

Conclusion

Higher intrathoracic pressures were achieved by OP in this study. However, further studies are needed to validate these effects of overlapping thumbs technique in infant cardiopulmonary resuscitation, not manikin.
Mental health risk factors for suicides in the US Army, 2007–8
Authors: Bachynski Kathleen E , Canham-Chervak Michelle , Black Sandra A , Dada Esther O , Millikan Amy M , Jones Bruce H
Published: March 2012

Objective

Suicides among active duty US Army personnel have been increasing since 2004, surpassing comparable civilian rates in 2008. This analysis uses US military data to assess suicide rates for the 2-year period 2007–8, and examines relative risks (RR) of suicide associated with mental health disorders.

Methods

Historical trends of US Army suicides were assessed using 1977–2008 data from Army G-1 (Personnel). Suicide rates, RR and the 2000–8 trends of mental health disorders were calculated using data from the Defense Casualty Information Processing System and Defense Medical Surveillance System.

Results

A total of 255 soldiers committed suicide in 2007–8 (2008 rate 20.2 per 100 000). Factors associated with higher suicide risk included male gender, lower enlisted rank and mental health disorders treated on an outpatient basis (RR 3.9), as well as a number of mental health disorders (mood disorders, anxiety disorders, post-traumatic stress disorder, personality/psychotic disorders, substance-related disorders and adjustment disorder; RR range 4.7–24.5). Analysis of historical trends suggested that 25–50% of the suicides that occurred in 2008 might have been related to the major commitment of troops to combat beginning in 2003.

Conclusions

The recent increase in suicides parallels an increase in the prevalence of mental disorders across the army. This finding suggests that increasing rates of clinically treated psychopathology are associated with increasing rates of suicides; these rates probably serve as sentinels for suicide risk in this population. Soldiers seeking treatment for mental disorders and substance abuse should be a focus for suicide prevention.
MICROSTRUCTURES AND DRY SLIDING WEAR RESISTANCE OF THE LASER CERAMICS COMPOSITE COATING ON PURE Ti
Authors: LIU PENG , ZHANG YUANBIN , LUO HUI , HUO YUSHUANG
Published: March 2012

In this study, Al–Ti–Co was used to improve the surface performance of pure Ti . Laser cladding is an important surface modification technique, which can be used to improve the surface performance of pure Ti . Laser cladding of the Al–Ti–Co + TiB2 pre-placed powders on pure Ti can form ceramics reinforced the composite coating, which improved the wear resistance of the substrate. Characteristics of the composite coating were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), microhardness and wear tests. And the laser-cladded coating can also have major dilution from the substrate. Due to the action of the fine grain strengthening and the phase constituent, the wear resistance and microhardness of pure Ti surface were greatly improved.
FAILURE MECHANISM OF SINGLE-LAYER CYLINDRICAL RETICULATED SHELLS UNDER EARTHQUAKE MOTION
Authors: ZHI XU-DONG , FAN FENG , SHEN SHI-ZHAO
Published: March 2012

In order to have a good understanding of the failure mechanism of single-layer cylindrical reticulated shells under earthquake motions, two failure modes, that is, dynamic instability and dynamic strength failure, are studied of single-layer cylindrical reticulated shells under earthquake motion. The accumulation of material damages that may accelerate failure of these shells under dynamic actions is considered. The relationships between the structural responses under the ultimate loads are investigated through a systematic simulation study that covers different parameters. A method is proposed for classification of failure modes of the shells, using the fuzzy synthetic evaluation theory and the structural responses of different sample studies. The effectiveness of the proposed method is proved through applications to some examples. Finally, a damage model is established for identification of different structural damage levels and for determination of the ultimate load for strength failure.
INFLUENCE OF SINTERING CONDITIONS ON DOPED PZT CERAMICS FOR BASE-METAL ELECTRODE MULTILAYER ACTUATORS
Authors: DENNELER STEFAN , SCHUH CARSTEN , BENKERT KATRIN , MOOS RALF
Published: March 2012

The influence of sintering atmosphere and copper addition on the microstructural and piezoelectric properties of Mn -doped lead zirconate titanate ceramics (PZT) was investigated. This ceramic powder densifies below 1000°C, enabling the use of copper inner electrodes for a multilayer actuator setup. To simulate the influence of oxidized inner electrodes during sintering, different CuO contents (0 and 1 mol.%) were mixed to the precalcined Mn -doped PZT powder. Ceramic discs were sintered at 950°C in air and analogously in N2 , or in steam containing N2 (25 vol.% water vapor content). The electrical characterization of the discs showed that the piezoelectric properties are influenced by the CuO addition as well as by the sintering atmospheres. The large signal piezoelectric constant [Formula: see text] shows an improvement of at least 20% when CuO is added. CuO acts as a sintering aid, and especially when the ceramics are fired in steam-containing N2 , anomalous grain growth occurs.
SYNTHESIS AND PIEZOELECTRIC PROPERTIES OF (Ba1-xCax)(Ti1-yZry)O3 BY A NOVEL COMPOSITE-HYDROXIDE-MEDIATED APPROACH
Authors: KIMURA TAKESHI , YIN SHU , HASHIMOTO TAKATOSHI , SASAKI ATUSHI , TOKANO YUICHI , SATO TSUGIO
Published: March 2012

High purity ( Ba 1-x Ca x)( Ti 1-y Zr y) O 3((x,y)=(0.00,0.00)–(0.50,0.50)) were synthesized by a composite-hydroxide-mediated approach at 200°C using a sealed tube with a rolling system. The powders with an average size of 50 nm in diameter and narrow size distribution were produced. The highest electromechanical coupling factor k r was 36.1% ((x,y) = (0.05,0.03)) and highest mechanical quality factor Q m was 256 ((x,y) = (0.11,0.13)).
TEM MICROSTRUCTURE ANALYSIS FOR COMPRESSIVELY STRESSED Pb(Zr,Ti)O3 THIN FILMS BY CSD-DERIVED LaNiO3 BOTTOM ELECTRODES
Authors: OZAWA KOTARO , ISHIZUKA MASAAKI , SAKAMOTO NAONORI , OHNO TOMOYA , KIGUCHI TAKANORI , MATSUDA TAKESHI , KONNO TOYOHIKO , WAKIYA NAOKI , SUZUKI HISAO
Published: March 2012

Pb(Zr,Ti)O3 (PZT) possesses superior ferroelectric and piezoelectric properties arisen near a morphotropic phase boundary (MPB) composition, PbZr0.53Ti0.47O3 . We have prepared a PZT (MPB composition) thin film and perovskite-type LaNiO3 (LNO) electrodes on Si substrate by chemical solution deposition (CSD) method. The CSD-derived LNO bottom electrode applied compressive stress to the PZT film and enhanced the ferroelectric properties of the PZT film. TEM and SAED revealed that stress distribution and microstructures of the PZT/LNO/ Si films effectively influenced the ferroelectric properties.
SORPTION AND DESORPTION BEHAVIORS OF METHYLENE BLUE IN SOILS AMENDED WITH RICE-STRAW-DERIVED ASH AND BIOCHAR
Authors: LIU XINZHONG , CHEN RONGGUO , WENG RENGUI , CHEN YILAN , PENG LEI , XIU FURONG
Published: March 2012

The ash (Ash) and biochar (BC) derived from the partial combustion of rice-straw are ubiquitous in soils and sediments and can potentially affect the environmental fate of organic contaminants. In this study, the effects of Ash and BC on the sorption and desorption behaviors of methylene blue (MB) were investigated. Ash was obtained from the direct burning of the rice-straw, and BC was separated from Ash by HCl treatment. SEM, BET, FT-IR, and pore size distribution analyses were used to characterize the Ash and BC prepared. Sorption capacities of MB on Ash-amended soil (AS) and BC-amended soil (BS) increased significantly with increasing contents of Ash and BC in soils. Sorption isotherms of soil amended with various amounts of Ash or BC fitted better to the Langmuir equation. The significant increase of apparent desorption hysteresis could be observed with increasing content of Ash or BC in the soils, especially in the case of BC, presumably due to the presence of micropores, hydroxyl groups and relatively higher specific surface area. It is believed that the presence of small amounts of BC produced from the rice-straw-derived ash in soil can have a marked effect on the transfer behavior of dye contaminations.
Preparation of Bulk Heterojunction Composite Consisting of Poly(3-hexylthiophene) and Neat C70 Using Halogen-Free Solvent
Authors: Tada Kazuya , Onoda Mitsuyoshi
Published: March 2012

In terms of environmental friendliness, halogenated compounds including 1,2-dichlorobenzene (ODCB), which is a solvent frequently used in the preparation of polymer/fullerene bulk heterojunction composites for photocells, are not desirable. As a result of exploration in this context, 1,2,4-trimethylbenzene (TMB) has been found as a useful solvent for the preparation of poly(3-hexylthiophene) (P3HT)/C70 composite. A preliminary experiment has shown that the power conversion efficiency of a device with a P3HT/C70 composite film prepared from TMB solution reaches 0.45%, which is higher than the previously reported value for P3HT/C70-based devices prepared from ODCB solution by one order of magnitude.
Magnetic Response and Spin Polarization of Bulk Cr Tips for In-Field Spin-Polarized Scanning Tunneling Microscopy
Authors: Corbetta Marco , Ouazi Safia , Borme Jérôme , Nahas Yasmine , Donati Fabio , Oka Hirofumi , Wedekind Sebastian , Sander Dirk , Kirschner Jürgen
Published: March 2012

The magnetic properties of bulk Cr tips have been investigated by spin-polarized scanning tunneling spectroscopy (SP-STS). To extract the properties of the Cr tips, we performed low-temperature SP-STS measurements on a well-known model system: nanometric Co islands on Cu(111). Our experiments indicate the existence of uncompensated magnetic moments at the apex of the Cr tips, which rotate in the direction of the applied vertical magnetic field and become aligned with it at approximately 2 T. We extracted a tip spin polarization of 45% at the Fermi energy. We showed that the tip spin polarization can change with a modification of the tip apex.
Improvements in Optical Properties of (0001) ZnO Layers Grown on (0001) Sapphire Substrates by Halide Vapor Phase Epitaxy Using Thick Buffer Layers
Authors: Masuda Rui , Hsu Chih-Wei , Eriksson Martin , Kumagai Yoshinao , Koukitu Akinori , Holtz Per-Olof
Published: March 2012

The optical properties of (0001) ZnO layers grown at 1000 °C on (0001) sapphire substrates by halide vapor phase epitaxy (HVPE) were investigated by various photoluminescence (PL) measurements. A layer grown with a H2O/ZnCl2 (VI/II) ratio of 20 on a 0.4-µm-thick buffer layer exhibited a significant near-band-edge (NBE) peak blueshift and degraded internal quantum efficiency (ηint) due to residual compressive stress. Growth with a VI/II ratio of 600 diminished the NBE peak blueshift; however, deep level emission and a reduction of PL decay time (τPL) were caused by point defects generated by excess O source supply. A layer without the NBE peak blueshift and deep level emission was realized by growth with a VI/II ratio of 20 and a buffer layer of 0.8 µm. The ηint and τPL for HVPE-grown layers could be improved to 4.1% and 122.8 ps by using the thick buffer layer and appropriate VI/II ratio.
Low-Shrinkage Spin-On Glass for Low Parasitic Capacitance Gap-Filling Process in Advanced Memory Devices
Authors: Ryuzaki Daisuke , Sakurai Haruaki , Yoshikawa Takahiro , Torii Kazuyoshi
Published: March 2012

A new low-dielectric-constant spin-on glass (SOG) with a k value of 2.4 has been developed for a gap-filling process in advanced memory devices. The low-shrinkage characteristic of the SOG during thermal curing provides capabilities of gap filling and planarizing as high as those of conventional reflowable SOGs. The low-shrinkage SOG has thermal stability up to 800 °C and chemical stability against diluted hydrofluoric acid, sulfuric acid–hydrogen peroxide, and amine-based solutions, which makes it possible to be used as an interlevel dielectric of memory devices. Tungsten and aluminum interconnects fabricated using the low-shrinkage SOG showed a parasitic capacitance 30% lower than those fabricated using silicon dioxide and a sufficiently long line-to-line dielectric breakdown lifetime. Taking advantage of the high chemical stability of the SOG, an all-wet damageless via-formation process using an amine-based photoresist stripper has been developed. By using the process, the low-shrinkage SOG can be applied to multilevel metallization.
Enhancing the Efficiency and Contrast Ratio of White Organic Light-Emitting Diode Using Energy-Recyclable Photovoltaic Cells
Authors: Yokoyama Meiso , Wu Chung-Ming , Su Shui-Hsiang
Published: March 2012

We demonstrate that power recycling is feasible by using a semitransparent strip of Al electrode as an interconnecting layer to merge a white organic light-emitting device (WOLED) and an organic photovoltaic (OPV) cell. The device is called a photovoltaic organic light-emitting device (PVOLED). It has a glass/indium tin oxide (ITO)/copper phthalocyanine (CuPc)/4,4,4-tris(3-methyl-phenylphenylamino) triphenylamine (m-MTDATA):V2O5/2-N',N-bis(1-naphthyl)-N,N'-diphenyl-1'-biphenyl-4,4'-diamine (NPB)/4,4'-bis(carbazol-9-yl)biphenyl (CBP):bis[3,5-difluoro-2-(2-pyridyl) phenyl-(2-carboxypyridyl)] iridium(II) (FIrpic):4-(dicyanomethylene)-2-t-butyl-6 (1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB)/4,7-diphenyl-1,10-phenanthroline (BPhen)/LiF/Al/poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61butyric acid methyl ester (PCBM)/V2O5/Al structure. A power recycling efficiency of 10.133% is achieved using the WOLED of the PVOLED operated at 9 V and a brightness of 2110 cd/m2when the conversion efficiency of the OPV cell is 2.3%. We found that the power recycling efficiency decreases at a high brightness and a high applied voltage owing to an increase in the input power of the WOLED. A high efficiency (18.3 cd/A) and a high contrast ratio (9.3) are obtained in the device operated at 2500 cd/m2under an ambient illumination of 24000 lx. Reasonable white light emission with Commission Internationale De L'Eclairage (CIE) color coordinates of (0.32, 0.44) at 20 mA/cm2and a slight color shift occur in spite of the high current density of 50 mA/cm2.
A Novel Coplanar-Waveguide Band-Pass Filter Utilizing the Inductor–Capacitor Structure in 0.18 µm Complementary Metal–Oxide–Semiconductor Technology for Millimeter-Wave Applications
Authors: Lin Yo-Sheng , Huang Pen-Li , Wang Tao , Lu Shey-Shi
Published: March 2012

A low-insertion-loss V-band complementary metal–oxide–semiconductor (CMOS) band-pass filter is demonstrated. The proposed filter architecture has the following features: the low-frequency transmission-zero (ωz1) and the high-frequency transmission-zero (ωz2) can be tuned individually by adjusting the value of the series capacitor (C
s) and the size of the built-in inductor–capacitor (LC) resonator, respectively. The folded short-stub technique is used to reduce the chip size of the filter. To reduce the silicon substrate loss, the CMOS-process-compatible backside inductively-coupled-plasma (ICP) deep trench technology is used to selectively remove the silicon underneath the filter. After the ICP etching, the filter achieves insertion-loss (1/S
21) lower than 3 dB over the frequency range of 46.5–85.5 GHz. The minimum insertion-loss is -1.8 dB at 60 GHz.
A Computational Study on the Electronic Properties of Armchair Graphene Nanoribbons Confined by Boron Nitride
Authors: Noei Maziar , Fathipour Morteza , Pourfath Mahdi
Published: March 2012

In this paper, we present a computational study on the electronic and charge transport properties of armchair boron nitride-confined graphene nanoribbon structures. We compare the electronic bandstructure of hydrogen passivated armchair graphene nanoribbons (AGNRs) with the bandstructure of boron nitride-confined AGNRs. Our study reveals that due to the energy gap opening in (3p+2) AGNRs in these novel hybrid structures and the possibility of realizing parallel arrays of semiconducting and isolating nanoribbons in them, they can be considered as better candidates for electronic applications than hydrogen passivated AGNRs. We also calculate the charge transmission probability and density of states in these nanostructures and investigate their behavior under different biases. In doing so, we have used the non-equilibrium Green's function formalism to solve the Schrödinger equation and have coupled it to a two-dimensional Poisson-solver for treating the electrostatics of the system.
Optimized Process of Mn2+-Doped Ba0.5Sr0.5TiO3 Thin Films on Platinum Coated Sapphire Substrates
Authors: Zhu Bin , Jiang Shuwen , Yang Chengtao , Li Ping , Zhang Jihua
Published: March 2012

Mn2+-doped Ba0.5Sr0.5TiO3 (BST) thin films were prepared on Pt-coated sapphire substrates by RF magnetron sputtering. By analyzing the energy state of particles during the sputtering, deposition parameters (substrate temperature, sputtering power, and atmosphere) were optimized for superior dielectric properties. Our results indicated that a compromise of relatively high tunability and low loss could be achieved. Resultant BST thin films has a tunability of 50% and dielectric loss of 0.64% at an applied field of 1.2 MV/cm, under optimized sputtering conditions of substrate temperature at 750 °C, pressure at 4 Pa with an O2/(O2+ Ar) mixing ratio of 50%, and sputter RF power density at 6.8 W/cm2.
Defect Propagation from 3C-SiC Intermediate Layers to III–Nitride Epilayers
Authors: Abe Yoshihisa , Fujimori Hiroyuki , Watanabe Arata , Ohmori Noriko , Komiyama Jun , Suzuki Shunichi , Nakanishi Hideo , Egawa Takashi
Published: March 2012

The propagation of crystal defects from a 3C-SiC intermediate layer (3C-SiC IL) to hexagonal III–nitride epilayers formed by a metalorganic vapor phased epitaxy (MOVPE) has been investigated by observing the interface between the 3C-SiC IL and the hexagonal III–nitride epilayers. The 3C-SiC(111) IL grown on a Si(111) substrate has many stacking faults (SFs) that form along the 3C-SiC111 planes. The density of the SFs decreases with separation from the Si substrate. The initial III–nitride epilayers have V-shaped trenches due to the SFs of the 3C-SiC IL. However, there are some SFs, that do not generate V-shaped trenches. On the basis of high-resolution cross-sectional observations by transmission electron microscopy and X-ray pole-figure analysis, an atomic model for the SFs is considered in terms of twin bands of 3C-SiC. V-shaped trenches were determined to be formed on protrusions consisting of the twin bands in the 3C-SiC IL.
Spatial Inhomogeneity of Aluminum Content in Air-Bridged Lateral Epitaxially Grown AlGaN Ternary Alloy Films Probed by Cross-Sectional Scanning Near-Field Optical Microscopy
Authors: Ishibashi Akihiko , Murotani Hideaki , Yokogawa Toshiya , Yamada Yoichi
Published: March 2012

We systematically studied spatial inhomogeneity of aluminum content in air-bridged lateral epitaxially grown (ABLEG) AlGaN ternary alloy films by high-resolution photoluminescence mapping probed with cross-sectional scanning near-field optical microscopy (SNOM). We observed the content changes along the vertical <0001> and the horizontal <112̄0> growth directions in AlGaN films with four different mask widths. The spatial inhomogeneity was determined by considering the following factors: the different growth rates of the lateral and vertical directions, the aluminum and gallium adatom supplies from a gas that depend on mask width, and the aluminum and gallium adatom diffusions on the (0001) and (112̄0) facets.
Thermophysical Properties of Transparent Conductive Nb-Doped TiO2 Films
Authors: Tasaki Chihiro , Oka Nobuto , Yagi Takashi , Taketoshi Naoyuki , Baba Tetsuya , Kamiyama Toshihisa , Nakamura Shin-ichi , Shigesato Yuzo
Published: March 2012

The thermophysical properties of Nb-doped TiO2 (Nb:TiO2) films were studied in terms of electrical conductivity and Nb concentration. The thermal diffusivity of Nb:TiO2 films with various Nb concentrations was investigated and found to range from (1.2–2.1)×10-6 m2 s-1. The thermal conductivity of Nb:TiO2 films with 8.5 at. % Nb concentration is proportional to the electrical conductivity in conformity with the Wiedemann–Franz law. The thermal conductivity carried by phonons, λph, of Nb:TiO2 films decreased with increasing Nb concentration. The mean free path of phonons, l
ph, in Nb:TiO2 films was estimated to be almost the same as the average distance between Nb impurities. The grain size was much larger than l
ph. Thus, phonon scattering by Nb impurities should be the dominant factor for the change in λph.
Effect of Electric Potential and Mechanical Force on Copper Electro-Chemical Mechanical Planarization
Authors: Chen Sheng-Wen , Kung Te-Ming , Liu Chuan-Pu , Chang Shih-Chieh , Cheng Yi-Lung , Wang Ying-Lang
Published: March 2012

In this study, the dependence of Cu electrochemical mechanical planarization (ECMP) rate on electric potential and mechanical force in electrolyte is investigated using potentiodynamic analysis, electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). In chemical etching, CMP, electropolishing, and ECMP processes, the Cu removal rate is mainly affected by the interplay between electric potential and mechanical force. An equivalent circuit is built by fitting the EIS results to explain the behavior of Cu dissolution and Cu passive film. The Cu dissolution rate increased with decreasing charge-transfer time-delay. The resistance of the Cu passive film (R
p) is proportional to the intensity ratio of Cu2O/[Cu(OH)2+ CuO].
An Analytical Approach to Modeling Static Behavior of Torsional Nano-/Micro-actuators under Effect of van der Waals Force
Authors: Moeenfard Hamid , Darvishian Ali , Ahmaidan Mohammad Taghi , Zohoor Hassan
Published: March 2012

In this research, the static behavior of torsional nano-/micro-actuators under van der Waals (vdW) force is studied. First, the equilibrium equation governing the static behavior of torsional nano-/micro-actuators under vdW force is obtained. Then the energy method is utilized to investigate the statical stability of nano-/micro-actuator equilibrium points and a useful equation is suggested for the successful and stable design of nano-/micro-actuators under vdW force. Then, the equilibrium angle of nano-/micro-actuators is calculated both numerically and analytically using the homotopy perturbation method (HPM). It is observed that, with increasing instability number, defined in this paper, the rotation angle of the actuator is increased and pull-in suddenly occurs. Since analytical results are in good agreement with the numerical ones, the analytical method presented in this paper can be used as a fast, precise, and stable design tool in nano-/micro-actuators under vdW force.
Density Dependence of the Longitudinal Diffusion Coefficient of Electrons in Xenon
Authors: Kusano Hiroki , Matias-Lopes José A. , Miyajima Mitsuhiro , Shibamura Eido , Hasebe Nobuyuki
Published: March 2012

The longitudinal diffusion coefficient of electrons and the ratio of the longitudinal diffusion coefficient to the mobility of electrons were measured for the first time in high-density gaseous xenon in the extensive density range of 4.19×1019–4.82×1020 cm-3. The density dependence of the longitudinal diffusion coefficient was observed in the reduced electric field range of 0.025–0.055 Td.