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In this study, the microscopic transport properties of porous gas diffusion media (PGDMs) with capillary meniscus formation are evaluated using a statistical approach for electrochemical applications. The microscopic morphology of PGDM is stochastically modeled using randomly distributed carbon fibers and various meniscus formations. In particular, the meniscus formation of hydrophobic polytetrafluorethylene (PTFE) agent enables the generation of highly elaborate microstructures in commercial PGDMs. A single-phase three-dimensional 19-velocity lattice Boltzmann method is applied to simulate the microscale mass transfer phenomena within the PGDMs. The mass transport characteristics (i.e., anisotropic permeability, tortuosity, and effective diffusion coefficient) of the PGDM samples with different PTFE content are statistically investigated as a function of untreated porosity (i.e., porosity before PTFE loading) of the PGDMs. The predicted results reveal an inverse relationship between anisotropic permeability and PTFE loading because the addition of PTFE decreases the bulk porosity of the PGDMs. In addition, the electrical and thermal conductivities of PGDMs are statistically estimated in both the in-plane and through-plane directions. The results show that the in-plane electrical and thermal conductivities are greater than those in the through-plane direction because of the carbon-fiber orientation. Moreover, the addition of PTFE has relatively larger effects on the through-plane electrical and thermal conductivities.

This study is a direct hands-on epidemiological sampling of a hospital data of registered patients for tuberculosis (TB) in the Kasungu District Hospital of Malawi. The data for the year 2013 and 2014 were chosen as the latest but random sample to analyze whether the data fit in and follow the broad pattern of the country at the national level and also at the global level. The data represent convoluted results of genuine TB diagnosis and latency, but impacted by the socio-cultural mindset to obtaining health care in general. Incidences of human immunodeficiency virus (HIV) run in close parallel to TB as the former precariously enhance the vulnerability from TB infection to the disease stage. Key words: Tuberculosis (TB), Malawi, human immunodeficiency virus (HIV).

The current study has been undertaken by studying the data from the hospital registers at the Kasugu District Hospital, Malawi. The malaria cases of 2014 were chosen for the study. They typically represent disease distribution based on the ages and genders of the patients. The data suggest that the cure rates among patients under age 5 and above do not have any significant difference, contrary to the commonly anticipated outcome that the older children should have better developed immune systems and should have higher cure rates. A notable point is there are huge dichotomies between genders in terms of the reported registered cases, the cure and mortality rates. The gender differentiation in the reporting and management of malaria is understood under the contemporary socio-cultural beliefs and economic realities of the Malawian society. This analysis has been carried out from a qualitative perspective, but with an attempt to identify a pattern from a year's length of statistical data. Key words: Malaria epidemiology, malaria cases, mortality, case fatality rates.

High surface area (∼300 m 2 /g) nanostructured powders of (Nb 1−x Ir x )O 2 and (Nb 1−x Ir x )O 2 :10F (∼100 m 2 /g) have been examined as promising oxygen evolution reaction (OER) electro-catalysts for proton exchange membrane (PEM) based water electrolysis. Nb 2 O 5 and 10 wt.% F doped Nb 2 O 5 powders were prepared by a low temperature sol-gel process which were then converted to solid solution (Nb,Ir)O 2 and 10 wt.% F doped (Nb,Ir)O 2 [(NbIr)O 2 :10F] electro-catalysts by soaking in IrCl 4 followed by heat treatment in air. Electro-catalyst powders of optimal composition (Nb 0.75 Ir 0.25 )O 2 :10F with ∼75 at.% reduction in noble metal content exhibited comparable OER activity to commercial hydrated IrO 2 and nanostructured in-house chemically synthesized IrO 2 . The (Nb,Ir)O 2 :10F electro-catalyst demonstrated excellent long term structural/corrosion stability comparable to in-house chemically synthesized pure IrO 2 :10F. First-principles calculations of the total energies, electronic structures and cohesive energies of the model systems have been performed and correlated to the excellent activity, long term stability of (Nb,Ir)O 2 :F for OER obtained experimentally.

Desiccating human red blood cells (RBCs) to increase their storage life has been the subject of intense research for a number of years. However, drying RBCs invariably compromises their integrity and has detrimental effects on hemoglobin function due to autoxidation. We have previously demonstrated an RBC desiccation and rehydration process that preserves RBC antigenic epitopes better than frozen RBCs. This study expands on those observations by examining what effects this desiccation process has on RBC hemoglobin function with respect to oxygen binding properties. In this paper, we examined RBCs from normal donors which were desiccated to 25% moisture content and stored dry for 2 weeks at room temperature prior to rehydration with plasma followed by structural and functional studies. Our data showed that approximately 98% of the RBCs were intact upon rehydration based on hemolysis assays. Oxygen dissociation curves for the desiccated/rehydrated RBCs showed a left shift compared to fresh RBCs (pO2 = 17 mmHg vs. 26 mmHg, respectively). The desiccated/rehydrated RBCs also showed an increase in methemoglobin compared to fresh RBCs (4.5% vs 0.9%, respectively). 2,3-Diphosphoglycerate concentration of the desiccated/rehydrated RBCs was reduced by 20%. In conclusion, although this RBC dehydration process preserves RBC integrity and hemoglobin oxygen binding properties better than most other dehydration techniques described so far, further optimization and long-term studies are needed to make this procedure acceptable for human transfusion.

In the present study, microscale transport phenomena in gas diffusion layers (GDLs) with gradient porosities are investigated statistically. A series of GDLs are randomly generated with linear and nonlinear gradient porosities at a 95% confidence level to reflect the heterogeneous microstructures. Straight-cylindrical carbon fibers with a uniform diameter are randomly arranged layer-by-layer and then treated with various polytetrafluoroethylene (PTFE) loadings. Furthermore, the reactant transport phenomena throughout the GDLs are simulated using lattice Boltzmann method (LBM). Then, the corresponding mass transport characteristics (i.e., permeability, tortuosity, and effective diffusion coefficient) are predicted in a series of GDL samples. The predicted data reveal an inverse relationship between permeability and PTFE loading. Moreover, the results show that GDLs with gradient porosities are more favourable to the reactant gas diffusion, leading to larger permeability than those of GDLs with uniform porosities. Besides, electrical and thermal conductivities of GDLs are computed in both in-plane and through-plane directions, and show good agreement with published experimental data. These statistical results show that the microscopic transport characteristics of PTFE-treated GDLs with gradient porosities are strongly affected by porosity distribution and PTFE loading. The proposed model can be utilized to optimize GDL structures and investigate the effect of PTFE on microscale transport characteristics of GDLs.

The high voltage spinel form of LiMn1.5Ni0.5O4 (LMNO) with a particle size ∼10–40 nm has been synthesized for the first time using high energy mechanical milling (HEMM) followed by low temperature thermal treatments using Li2O, MnO2 and NiO as the starting precursors. The nanostructured LMNO cathode, synthesized by the simple, but effective HEMM process followed by thermal treatments to refine the structure in the temperature range ∼573–1073 K, exhibits a reversible capacity ∼120–110 mAh/g when cycled at a rate of ∼20 mA/g in the potential window ∼3.6–5.1 V. The electrochemical results are comparable to capacity values reported in the literature for LMNO derived using various other methods suggesting the efficacy of HEMM as an attractive and viable alternative approach for synthesizing battery grade high voltage spinel phase, LMNO.

Fluorine doped iridium oxide (IrO2:F) powders with varying F content ranging from 0 to 20 wt.% has been synthesized by using a modification of the Adams fusion method. The precursors (IrCl4 and NH4F) are mixed with NaNO3 and heated to elevated temperatures to form high surface area nanomaterials as electro-catalysts for PEM based water electrolysis. The catalysts were then coated on a porous Ti substrate and have been studied for the oxygen evolution reaction in PEM based water electrolysis. The IrO2:F with an optimum composition of IrO2:10 wt.% F shows remarkably superior electrochemical activity and chemical stability compared to pure IrO2. The results have also been supported via kinetic studies by conducting rotating disk electrode (RDE) experiments. The RDE studies confirm that the electro-catalysts follow the two electron transfer reaction for electrolysis with calculated activation energy of ∼25 kJ mol−1. Single full cell tests conducted also validate the superior electrochemical activity of the 10 wt.% F doped IrO2.

Nanocrystalline NaMn 2 O 4 with a crystallite size of ∼8–10 nm exhibiting a new close packed hexagonal crystalline form, different from the known stable orthorhombic ( Pbam or Pmnm symmetry) or monoclinic structures common to the Na–Mn–O system, has been synthesized by a high energy mechano-chemical milling process (HEMM) using Na 2 O 2 and Mn 2 O 3 as starting materials. The newly synthesized structure of NaMn 2 O 4 has been studied as a cathode for sodium ion rechargeable batteries. The HEMM derived NaMn 2 O 4 shows a 1st cycle discharge capacity ∼75 mAh/g, ∼86 mAh/g and ∼95 mAh/g when cycled at a rate of ∼40 mA/g in the potential window ∼2.0–4.0 V, ∼2–4.2 V and ∼2–4.5 V, respectively. The nanostructured NaMn 2 O 4 shows a fade in capacity of 0.3% per cycle and a moderate rate capability when cycled in the potential window 2–4 V. However, electrolyte decomposition occurring during charging of the electrode above ∼3.8 V needs to be resolved in order utilize the full capacity of NaMn 2 O 4 as well as improve the stability of the electrode.

Purpose: To evaluate the factors affecting the bone union time and the occurrence of nonunion after intramedullary nailing of subtrochanteric femoral fractures in adults. Materials and Methods: We retrospectively reviewed data from 31 patients (22 men and 9 women) who had undergone femoral intramedullary nailing at least 1 year post-operatively and analyzed the bone union time, nonunion rates, and factors that affected the bone union time according to the fracture classification (AO and Fielding classifications), comminution of the medial cortex, reduction method, and additional cerclage wiring. Results: The average union time was 26.4 weeks. There were no differences in the bone union time according to the fracture classification, reduction method, or additional cerclage wiring. Significant differences were found in the bone union time between the medial cortex comminution and non-comminution groups. A relatively strong positive correlation was detected between the degree of post-operative displacement and the bone union time. Nonunion occurred in three cases and there was no failure of implants. Conclusion: The bone union time was not affected by the reduction method nor additional cerclage wiring in intramedullary nailing of subtrochanteric femur fractures. Comminution of the medial cortex and the degree of the postoperative displacement of fractures contributed to the delayed time of union.

Identification of electro-catalysts containing non-noble metal or significantly reduced amounts of expensive noble metals ( e.g. RuO 2 ) is highly desirable. Development of such a catalyst with comparable electrochemical performance to the standard noble metal oxide for proton exchange membrane (PEM) based water electrolysis would constitute a pioneering breakthrough in hydrogen generation by water electrolysis. In line with these goals, by exploiting a two-pronged theoretical first principles and experimental approach herein we demonstrate that a nano-structured solid solution of SnO 2 :10 wt% F containing only 20 at.% RuO 2 [ e.g. (Sn 0.80 Ru 0.20 )O 2 :10F] displays a remarkably similar electrochemical activity and moreover, comparable or even much improved electrochemical stability and durability compared to pure the noble metal counterpart, RuO 2 . Density functional theory calculations have demonstrated direct dependence of the catalytic activity on the electronic structure peculiarities of the F-doped (Ru,Sn)O 2 which corresponds well with the experimental results.

An inexpensive, facile, and high throughput synthesis of silicon nanoparticles was achieved by the mechano-chemical reduction reaction of magnesium silicide (Mg 2 Si) and silicon monoxide (SiO) using a high energy mechanical milling (HEMM) technique followed by acid leaching. Characterization of the resultant product using X-Ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and surface area analyses was performed at various stages of the synthesis process. XRD patterns show that the final product formed is single phase silicon and the nanocrystalline nature was confirmed by the shifted transverse optical (TO) band, characteristic of nc-Si determined by Raman analysis. SEM and TEM shows the presence of particles of different sizes in the range of few nanometers to agglomerates of few microns which is consistent with products obtained from mechanical milling. BET measurements show a very high specific surface area (SSA) of ~190 m 2 /g obtained due to acid leaching which is also validated by the porous nature of the particles confirmed by the SEM images.

Advanced dual control gate with surrounding floating gate (DC-SF) cell process and operation schemes are successfully developed for 3-D nand flash memories. To improve performance and reliability of DC-SF cell, new metal control gate last (MCGL) process is developed. The MCGL process can realize a low resistive tungsten (W) metal wordline, a low damage on tunnel oxide/inter-poly dielectric (IPD), and a preferable floating gate (FG) shape. Also, new read and program operation schemes are developed. In the new read operation, the higher and lower Vpass-read are alternately applied to unselected control gates to compensate lowering FG potential to be a pass transistor. In the new program scheme, the optimized Vpass are applied to neighbor WL of selected WL to prevent program disturb and charge loss through IPD. Thus, by using the MCGL process and new read/program schemes, the high performance and reliability of the DC-SF cell can be realized for 3-D nand flash memories.

Room temperature solid state diffusion reaction induced by mechanical alloying (MA) of elemental blends of Mg, Zn and Ca of nominal composition 60 at.% Mg–35 at.% Zn–5 at.% Ca has been studied. Formation of fully amorphous structure has been identified after 5 h of MA performed in a SPEX 8000M shaker mill, with milling continued up to 8 h to confirm the formation of homogeneous amorphous phase. Thermal stability of the amorphous phase has been studied using differential scanning calorimetry (DSC) and isothermal heat treatment at different temperatures. The amorphous powder consolidated using cold isostatic pressing (CIP) showed an envelope density ∼80% of absolute density, which increased to an envelope density ∼84% of absolute density after sintering at an optimized temperature of ∼523 K for 9 h. Electrochemical bio-corrosion testing of the CIP compacted amorphous pellet as well as the sintered pellet performed in Dulbecco's Modified Eagle Medium, showed improved corrosion resistance in comparison to the as-cast pure Mg. Cytotoxicity testing of the CIP compacted amorphous pellet, performed using the MTT assay with MC3T3 osteoblastic cells, showed low cytotoxicity in comparison to the as-cast pure Mg.

Mg 60 Zn 40− х Ca х ( х = 5, 3, 1) powders and thin films have been produced by high energy mechanical alloying (HEMA) and pulsed laser deposition (PLD), respectively and the influence of PLD processing parameters on the microstructures of the Mg–Zn–Ca amorphous thin film was investigated using XRD, TEM, HRTEM and XEDS. Amorphous powder and thin film corresponding to Mg 60 Zn 35 Ca 5 composition have been successfully generated. The substrate temperature appears to be the dominant PLD processing parameter among others contributing to the formation of amorphous thin film.

The buffering effect of carbon on the structural stability of amorphous silicon films, used as an anode for lithium ion rechargeable batteries, has been studied during long term discharge/charge cycles. To this extent, the electrochemical performance of a prototype material consisting of amorphous Si thin film (∼250 nm) deposited by radio frequency magnetron sputtering on amorphous carbon (∼50 nm) thin films, denoted as a -C/Si, has been investigated. In comparison to pure amorphous Si thin film ( a -Si) which shows a rapid fade in capacity after 30 cycles, the a -C/Si exhibits excellent capacity retention displaying ∼0.03% fade in capacity up to 50 cycles and ∼0.2% after 50 cycles when cycled at a rate of 100 μA/cm 2 (∼C/2) suggesting that the presence of thin amorphous C layer deposited between the Cu substrate and a -Si acts as a buffer layer facilitating the release of the volume induced stresses exhibited by pure a -Si during the charge/discharge cycles. This structural integrity combined with microstructural stability of the a -C/Si thin film during the alloying/dealloying process with lithium has been confirmed by scanning electron microscopy (SEM) analysis. The buffering capacity of the thin amorphous carbon layer lends credence to its use as the likely compliant matrix to curtail the volume expansion related cracking of silicon validating its choice as the matrix for bulk and thin film battery systems.

Suspensions of ZnO nanoparticles in water were prepared with the two-step powder dispersion process using several methods of ultrasonication. The dispersion of ZnO was found to proceed by a fragmentation process, with minimum achievable particle size in the range 50 to 300 nm. This is consistent with other oxide nanopowder systems, in which most primary particulates still remain in hardened aggregates that cannot be further reduced. A submersible accelerometer probe was developed and used to measure the relative ultrasonic energy field in the liquid for the various ultrasonication methods. Oscillation at the expected frequencies was identified in each case, with strong variability at different locations in the liquid volume.

Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles.

Bulk metallic glasses are adequate for micro-forming because of the viscous flow in the supercooled liquid state. The deformation behavior of Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 alloy under compression in the supercooled liquid state were investigated by using DSC and TMA. Based on the deformation behavior, micro-forming process of Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 alloy was designed and carried out. The surface of the deformed specimens were analyzed by SEM, XRD, and AFM. The roughness of the specimen surface exhibited a correlation with the total deformation and a new parameter reflecting roughness evolution of the deformed surface was suggested as the relative comparison among different forming conditions.

The crystallization behavior of Cu and Zr-base Bulk Metallic Glass were investigated using the electrical resistivity measurements in isothermal annealing. Electrical resistivity evolutions exhibited one or two stage of resistivity reduction according to additional elements respectively. In order to analyze the electrical resistivity reduction, micro structure evolutions were analyzed using DSC, XRD, and TEM.

The crystallization behavior of Cu 43 Zr 43 Al 7 Ag 7 (numbers indicate at.%) bulk metallic glass was investigated using the isothermal electrical resistivity measurements at 450 °C in the supercooled liquid region. The crystallization process is a single step phase transformation. To analyze the electrical resistivity reduction, microstructure evolutions were analyzed using differential scanning calorimetry, X-ray diffraction, transmission electron microscopy and small-angle X-ray scattering. The Avrami parameter of the electrical resistivity reduction step was 1.73, indicating that the crystallization process is a diffusion-controlled growth of intermetallic compounds with decreasing nucleation rate.

The growth kinetics of WSi2 coating formed by chemical vapor deposition (CVD) of Si on a W substrate at temperatures between 1000 and 1200 °C using SiCl4–H2 gas mixtures was investigated and its isothermal oxidation resistance in 80% Ar–20% O2 atmosphere was evaluated at temperatures between 800 and 1300 °C. WSi2 coating grew with a parabolic rate law after an initial incubation period, indicating the diffusion-controlled growth. The activation energy for growth of WSi2 coating was about 42.5 kcal/mol. The isothermal oxidation rate of WSi2 coating increased with increasing oxidation temperature but rapidly decreased at 1300 °C. The oxidation product of WSi2 coating was composed of the WO3 particles embedded in the amorphous SiO2 matrix at below 1200 °C but consisted of only SiO2 phase at 1300 °C. The fast oxidation behavior of WSi2 coating at below 1200 °C was attributed to the formation of many cracks and pores, i.e. short-circuit diffusion path of oxygen, within the oxide scale, which resulted from the internal stress generated both by the large volume expansion caused by the oxidation reactions of WSi2 and by the evaporation of WO3 phase. The slow oxidation behavior of WSi2 coating at 1300 °C was due to the exclusive formation of a slow-growing continuous SiO2 scale by the rapid evaporation of WO3 phase.

The crystallization behavior of the Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 bulk metallic glass was investigated using the isothermal electrical resistivity measurements at 390 °C in the super-cooled liquid region. The crystallization process is completed through two sequential phase transformations. The first phase transformation was the formation of icosahedral phases, which is followed by the formation of intermetallic compounds.

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or "nanofluids," was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (�10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise. � 2009 American Institute of Physics.

This research suggested a method of analyzing how the driver's anthropometric data would best be accommodated by a specific driver-vehicle interface. Three-dimensional manikins with 18 links were developed using US 95th percentile male and 5th percentile female's anthropometric data. In addition, an adjustable seating buck was constructed to control seven package variables. The levels of each package variables were determined according to the interior dimensions of mid-size passenger vehicles. After the manikins were situated on each derivable driving environment of the seating buck's package variable levels, 3-D cartesian coordinate values were collected from the manikin's articular points by using a coordinate measuring machine. The data were then converted into joint angles of manikins for suggesting suitable driving environments by considering appropriate driving postures.

We present the steady-state and time-resolved photoluminescence (PL) spectra of poly(p-phenylenevinylene)derivatives, which exhibit a marked dependence on the side chains attached to the main chain...

Two copolymers of poly(p-phenylenevinylene) (PPV) containing low levels (0.8 and 3.6 mole %) of the 2,3,5,6-tetramethyl-I 4-phenylenevinylene (TMPV) units were prepared via the sulfonium salt precursor route, The luminescence properties of the two copolymers were studied in detail mainly for photoluminescence (PL) and electroluminescence (EL) characteristics in comparison with those of PPV itself. Inclusion of low levels of TMPV units improves EL efficiency by more than 10 times when a single layer device was constructed using ITO coated glass anode and aluminum metal cathode. This was explained by the possible partial disruption of main chain π-conjugation by the TMPV units which force its phenylene or vinylene structure to twist out of the coplanar structure in order to avoid of the steric repulsion between the methyl and vinyl protons in the TMPV units. The UV-vis, PL and EL spectra of the copolymers support this supposition.

New, wholly aromatic polyesters carrying 9,10-diphenylanthracene fluorophores along the main chain or both in the pendent and main chain were prepared and their properties were studied by differential scanning calorimetry, wide-angle X-ray diffractometry and fluorometry in solution as well as in thin solid films. The diphenylanthracene pendent groups are attached to the terephthaloyl unit of the aromatic polyester main chains through the oxyhexamethyleneoxy spacer. Two of the polymers were found to be thermotropic and all of the polymers exhibited relatively strong photoluminescence in solution as well as in thin films. Their fluorescence behavior is discussed in relation to their structures. When the diphenylanthracene fluorophores exist either both in the main chain and the side chain or only in the side chain, the polyesters reveal photoluminescence over a broad range of wavelength from 400 to about 700 nm with the maximum emitting intensity at about 450 nm. The polymer that contains the same fluorophore only in the main chain, however, shows a rather sharp luminescence from about 420 to 550 nm, although its maximum emitting intensity is observed at the same wavelength (ca. 450 nm) as for other polyesters.

Photo- (PL) and electroluminescence (EL) properties of three different PPV derivatives carrying the 9,10-diphenylanthracene units are compared. One (polymer 1) of the polymers contains the 9,10-diphenylanthracene structure as an integral part of the main chain, but the other two have it as the pendent group attached to the main chain through either oxyethyleneoxy (polymer 2) or oxyhexamethyleneoxy (polymer 3) spacer. Polymers 1 and 2 exhibit very similar PL and EL spectra that are more or less of superimposed feature of the spectra from the backbones and the anthracene pendents. In contrast, polymer 3 shows an EL spectrum that is completely different from its PL spectrum. Whereas the PL spectrum of polymer 3 appears to be a combination of the spectra from the main chain and the pendents, as for polymer 1 and 2, the EL spectrum of polymer 3, however, looks as if the lights were emitted only from the backbone. This difference is explained in terms of excited state electronic interactions between the main chain and the pendents.

A series of new wholly aromatic polyesters was synthesized by melt polycondensation of 1-phenyl-2,6-naphthalenedicarboxylic acid (PNDA) and diacetates of various aromatic diols. The aromatic diols studied are hydroquinone (HQ), methylhydroquinone (MHQ), phenylhydroquinone (PHQ), (α-phenylisopropyl)hydroquinone (PIHQ), 2,6-naphthalenediol (2,6-ND), 1,4-naphthalenediol (1,4-ND), and 4,4′-biphenol (BP). These polyesters were characterized for their crystallinity, glass transition temperature (Tg), melting temperature (Tm), liquid crystallinity, and thermal stability. In general, crystallinity of the polyesters are very low and the Tg values of the polyesters range from 150 to 172°C depending on the structure of aromatic diols. All of the polymers formed nematic phases above their Tm or Tg. The polyesters derived from PHQ and PIHQ are soluble in chlorinated hydrocarbon solvents. The initial decomposition temperatures of the polyesters are above 400°C under N2 atmosphere. © 1996 John Wiley & Sons, Inc.

Two different series of new aromatic liquid crystalline (LC) polyesters were prepared from 3-phenyl-4, 4'-biphenyldicarboxylic acid (PBDA) and 1-phenyl-2, 6-naphthalenedicarboxylic acid (PNDA). PBDA and PNDA were polymerized with various aromatic diols such as hydroquinone, substituted hydroquinones, isomeric naphthalenediols and 4, 4'-biphenol, and the resulting polyesters were characterized by DSC, WAXD, and on a cross-polarizing microscope for the study of their thermal transition and crystallization properties, and mesophases formed therefrom.

Dependency of random-dopant-fluctuation (RDF) on NAND flash memory cells has been simulated. It has been shown that the RDF effects are more serious in NAND flash memory cells than in CMOS devices. The simulation results show the variation of threshold voltage, on- and off-current depending on the doping concentration. Also, the program and erase characteristics of NAND flash memory cells have been evaluated depending on the RDF effects.

A new Metal Control Gate Last process (MCGL process) has been successfully developed for the DC-SF (Dual Control gate with Surrounding Floating gate cell)[1] three-dimensional (3D) NAND flash memory. The MCGL process can realize a low resistive tungsten (W) metal word-line with high-k IPD, a low damage on tunnel oxide/IPD, and a preferable FG shape. And also, a conventional bulk erase can be used, replaced GIDL erase in BiCS[3][4], due to direct connection between channel poly and p-well by the channel contact holes. Therefore, by using MCGL process, high performance and high reliability of DC-SF cell can be achieved for MLC/TLC 256Gb/512Gb 3D NAND flash memories.