Components Of Si Research Articles

SYNTHESIS OF ZEOLITE AND COMPOSITE OF ZEOLITE/TiO2 FROM KAOLIN AND ITS APLICATION TO ADSORPTION-PHOTODEGRADATION OF METHILEN BLUE

<p>In this study, zeolite was synthesized from kaolin which was founded from Bangka Belitung as the starting material. Meanwhile, sodium silicate was used as silica source. Zeolite is material with many benefits, such as become an adsorbent. Kaolin has been used as starting material due to high content of silica and alumina, i.e 35 - 50 %. Zeolite was prepared by hydrothermal synthesis process, by mixing the metakaolin which was produced by calcination of kaolin at 700 °C for 6 hours, with sodium silicate and NaOH. The NaOH was used to activate the major components of Si and Al in the kaolin.The hydrothermal process was conducted at 100 °C for 24 hours with various concentrations of NaOH, i.e 1.5 N and 2.5 N. The NaOH concentration might determine the type of zeolite obtained. To improve the nature as adsorbent, zeolites modified into zeolit/TiO<sub>2</sub>. The addition of TiO<sub>2</sub>into the prepared zeolit aimed to produce a material with capability as adsorbent-photocatalyst. The result of research found that the addition of NaOH 1.5 N produced zeolite NaP1. Meanwhile, the addition of NaOH 2.5 N produced the NaP1 zeolite, zeolite X, and faujasite. The composite of zeolit/TiO<sub>2</sub>has ability on adsorption-photocatalytic as it was proven by methylene blue degradation under ultraviolet light.</p>

SYNTHESIS OF ZEOLITE AND COMPOSITE OF ZEOLITE/TiO2 FROM KAOLIN AND ITS APLICATION TO ADSORPTION-PHOTODEGRADATION OF METHILEN BLUE

<p>In this study, zeolite was synthesized from kaolin which was founded from Bangka Belitung as the starting material. Meanwhile, sodium silicate was used as silica source. Zeolite is material with many benefits, such as become an adsorbent. Kaolin has been used as starting material due to high content of silica and alumina, i.e 35 - 50 %. Zeolite was prepared by hydrothermal synthesis process, by mixing the metakaolin which was produced by calcination of kaolin at 700 °C for 6 hours, with sodium silicate and NaOH. The NaOH was used to activate the major components of Si and Al in the kaolin.The hydrothermal process was conducted at 100 °C for 24 hours with various concentrations of NaOH, i.e 1.5 N and 2.5 N. The NaOH concentration might determine the type of zeolite obtained. To improve the nature as adsorbent, zeolites modified into zeolit/TiO<sub>2</sub>. The addition of TiO<sub>2</sub>into the prepared zeolit aimed to produce a material with capability as adsorbent-photocatalyst. The result of research found that the addition of NaOH 1.5 N produced zeolite NaP1. Meanwhile, the addition of NaOH 2.5 N produced the NaP1 zeolite, zeolite X, and faujasite. The composite of zeolit/TiO<sub>2</sub>has ability on adsorption-photocatalytic as it was proven by methylene blue degradation under ultraviolet light.</p>

Systems intelligence inventory

Purpose Systems intelligence (SI) (Saarinen and Hämäläinen, 2004) is a construct defined as a person’s ability to act intelligently within complex systems involving interaction and feedback. SI relates to our ability to act in systems and reason about systems to adaptively carry out productive actions within and with respect to systems such as organizations, family and everyday life. This paper aims to develop an inventory to measure the SI construct. Design/methodology/approach A combination of exploratory and confirmatory factor analyses were carried out using data from self-report questionnaires. Findings Eight factors labeled systemic perception, attunement, attitude, spirited discovery, reflection, wise action, positive engagement and effective responsiveness are identified as the main components of SI. SI has associations with emotional intelligence but also captures additional dimensions. People in supervisor positions are found to score higher in a number of the SI factors. Originality/value A new measure is developed to evaluate and develop our ability to succeed in systemic contexts. The new measure is suggested to be particularly applicable in organizational contexts. It is directly related to the original core disciplines of the learning organization as described by Senge (1990), in particular personal mastery and systems thinking.

Multicomponent Analysis of the UV Si IV and C IV Broad Absorption Troughs in BALQSO Spectra: The Examples of J01225 + 1339 and J02287 + 0002

Broad Absorption Line QSOs (BALQSOs) are a subtype of radio-quite QSOs that exhibit complex and unusually broad (FWHM ≥ 2,000 km/s) absorption lines. The existence of these lines in BALQSO spectra raises some questions with respect to the properties, the physical conditions and kinematics of the BAL material as well as the morphology of BAL troughs. In this study, taking into consideration the clumpy structure of the AGN outflow winds, we propose a physical model in order to explain the formation of BAL troughs and we give the mathematical description of this model. We also propose a method for analyzing spectroscopically the BAL profiles in the UV region of the electromagnetic spectrum. This method consists of the criteria we set during the fitting process of BAL troughs. The purpose of these criteria is to enable us to determine the exact number of components needed to simulate accurately the BAL troughs and guarantee the uniqueness of the fit. We give an application of the model and the method for Si IV and C IV resonance lines in the case of two BALQSOs. From the analysis, we conclude that the BAL material is in the form of clouds (density enhancements) that move radially and intercept the line-of-sight to the central continuum source. Using our method, we find the number of absorption components needed to simulate the BAL profiles, which means the number of clouds in the line-of-sight. We calculate the velocity shifts, the FWHM and the optical depths of the absorption components of BALs and we propose an internal structure for these clouds. Finally, we give some correlations between the properties of absorption components of Si IV and C IV.

Deconvolving the controls on the deep ocean's silicon stable isotope distribution

We trace the marine biogeochemical silicon (Si) cycle using the stable isotope composition of Si dissolved in seawater (expressed as δ30Si). Open ocean δ30Si observations indicate a surprisingly strong influence of the physical circulation on the large-scale marine Si distribution. Here, we present an ocean general circulation model simulation that deconvolves the physical and biogeochemical controls on the δ30Si distribution in the deep oceanic interior. By parsing dissolved Si into its preformed and regenerated components, we separate the influence of deep water formation and circulation from the effects of biogeochemical cycling related to opal dissolution at depth. We show that the systematic meridional δ30Si gradient observed in the deep Atlantic Ocean is primarily determined by the preformed component of Si, whose distribution in the interior is controlled solely by the circulation. We also demonstrate that the δ30Si value of the regenerated component of Si in the global deep ocean is dominantly set by oceanic regions where opal export fluxes to the deep ocean are large, i.e. primarily in the Southern Ocean's opal belt. The global importance of this regionally dynamic Si cycling helps explain the observed strong physical control on the oceanic δ30Si distribution, since most of the regenerated Si present within the deep Atlantic and Indo-Pacific Oceans is in fact transported into these basins by deep waters flowing northward from the Southern Ocean. Our results thus provide a mechanistic explanation for the observed δ30Si distribution that emphasizes the dominant importance of the Southern Ocean in the marine Si cycle.

On-line monitoring of solar cell module production by ellipsometry technique

Non-destructive analyzing tools are needed at all stages of thin film photovoltaic (PV) development, and on production lines. In thin film PV, layer thicknesses, micro-structure, composition, layer optical properties, and their uniformity (because each elementary cell is connected electrically in series within a big panel) serve as an important starting point in the evaluation of the performance of the cell or module. An important focus is to express the dielectric functions of each component material in terms of a handful of wavelength independent parameters whose variation can cover all process variants of that material. With the resulting database, spectroscopic ellipsometry coupled with multilayer analysis can be developed for on-line point-by-point mapping and on-line line-by-line imaging.This work tries to review the investigations of different types of PV-layers (anti-reflective coating, transparent-conductive oxide (TCO), multi-diode-structure, absorber and window layers) showing the existing dielectric function databases for the thin film components of CdTe, CuInGaSe2, thin Si, and TCO layers.Off-line point-by-point mapping can be effective for characterization of non-uniformities in full scale PV panels in developing labs but it is slow in the on-line mode when only 15 points can be obtained (within 1min) as a 120cm long panel moves by the mapping station. In the last years [M. Fried et al., Thin Solid Films 519, 2730 (2011)], instrumentation was developed that provides a line image of spectroscopic ellipsometry (wl=350–1000nm) data. Up to now a single 30 point line image can be collected in 10s over a 15cm width of PV material. This year we are building a 30 and a 60cm width expanded beam ellipsometer the speed of which will be increased by 10×. Then 1800 points can be mapped in a 1min traverse of a 60∗120cm PV panel or flexible roll-to-roll substrate.

Expert System Approach to the Assessment of Spiritual Intelligence Impact for Decisionmaking Performance

Abstract Background: In contrast to the rational (IQ) and emotional intelligence (EQ), spiritual intelligence (SQ) is often underestimated and insufficiently investigated. This type of intelligence refers to our approach to the issue of the meaning and value of life, in terms that our actions are placed in a wider context. Objectives: The aim of this paper is to investigate in which extent spiritual intelligence determines the decision making process. In this context, the success of business decision is assigned as its functionality as one of the most prominent feature of successful decision. Methods: The inductive method of building an expert system, i.e. a knowledge based system (Doctus Knowledge-Based Expert System Shell) and casebased concluding on the degree of informativeness (with a key impact on functionality of decision) of individual components (Case Based Reasoning) are used in testing this relationship. Results: The study demonstrates the fact that most of respondents (managers) have not been even familiar with attributes of SI as well as their relationship with decision making process. Conclusions: Identification of the most significant components of SI that affect effectiveness of decisions would allow managers to focus on those which mostly contribute to the functionality of their decisions.

Morphology and mechanism study for the synthesis of ZrB2–SiC powders by different methods

ZrB{sub 2}–SiC ceramics, whose SiC is generally incorporated into the system by mechanical mixing, are known to have better performance than monolithic ZrB{sub 2}. Therefore, synthesis of duplex ZrB{sub 2}–SiC powders is beneficial for improving sinterability and mechanical properties of ZrB{sub 2}–SiC composites. In the present work, ZrB{sub 2}–SiC duplex powders with different morphologies were synthesized at 1550 °C for 2 h using as-synthesized amorphous hydrous ZrO{sub 2}–SiO{sub 2}. Both precipitation and sol–gel methods were used to prepare ZrO{sub 2}–SiO{sub 2} precursors. ZrB{sub 2}–SiC powder derived from precipitation method presented a rod-like morphology with smaller irregular particles adhering to them. And the morphology from sol–gel method was equiaxed shape with a very uniform distribution for principal components of Zr and Si. - Graphical abstract: SEM images of the ZrB2-SiC powders obtained by different methods. Display Omitted - Highlights: • ZrB{sub 2}–SiC powders with different morphologies were synthesized. • Precipitation and sol–gel methods were used to prepare ZrO{sub 2}–SiO{sub 2} precursors. • Possible mechanisms of morphology formation were investigated. • This work provided a potential way of morphology control for raw powders. • The synthesized duplex powders achieved a uniform distribution of SiC in ZrB{sub 2}.

Spectropolarimetry of the Type Ia supernova 2012fr

Abstract Spectropolarimetry provides the means to probe the 3D geometries of supernovae (SNe) at early times. We report spectropolarimetric observations of the Type Ia SN 2012fr at four epochs: −11, −5, +2 and +24 d, with respect to B-light-curve maximum. SN 2012fr is a normal Type Ia SN, similar to SNe 1990N, 2000cx and 2005hj (that all exhibit low velocity decline rates for the principal Si ii line). The SN displays high-velocity components at −11 d that are highly polarized. The polarization of these features decreases as they become weaker from −5 d. At +2 d, the polarization angles of the low-velocity components of silicon and calcium are identical and oriented at 90° relative to the high-velocity Ca component. In addition to having very different velocities, the high- and low-velocity Ca components have orthogonal distributions in the plane of the sky. The continuum polarization for the SN at all four epochs is low, <0.1 per cent. We conclude that the low level of continuum polarization is inconsistent with the merger-induced explosion scenario. The simple axial symmetry evident from the polarization angles of the high-velocity and low-velocity Ca components, along with the presence of high-velocity components of Si and Ca, is perhaps more consistent with the pulsating delayed detonation model. We predict that, during the nebular phase, SN 2012fr will display blueshifted emission lines of Fe-group elements.

Nanoporous SiCOH/CxHy dual phase films with an ultralow dielectric constant and a high Young's modulus

We used plasma-enhanced chemical vapor deposition (PECVD) of allyltrimethylsilane (ATMS), consisting of an allyl group along with three methyl groups attached to silicon, to form a low dielectric constant (low-k) and high modulus SiCOH matrix. We found that the dielectric constant and mechanical properties of the low-k material are strongly affected by the selection of the precursor, processing conditions such as the deposition temperature and post-treatment, the introduction of a second labile phase, and the chemical structure and composition of the films. After porogen (pore generator) treatment with cyclohexene oxide (CHO), the resulting material exhibited a low dielectric constant with excellent mechanical and thermal properties, having k ∼ 2.4 and a Young's modulus of 8.4 GPa. FT-IR and XPS results show that this is caused by the desorption of the labile phase (CxHy), the formation of Si–O cage-like structures, and changes in the chemical composition of films after thermal treatment. SiO2, SiO3, and SiO4 impart greater modulus and hardness to the films by increasing the stable component of Si–O in the SiCOH matrix.

THE VERY YOUNG TYPE Ia SUPERNOVA 2012cg: DISCOVERY AND EARLY-TIME FOLLOW-UP OBSERVATIONS

On 2012 May 17.2 UT, only 1.5 +/- 0.2 d after explosion, we discovered SN 2012cg, a Type Ia supernova (SN Ia) in NGC 4424 (d ~ 15 Mpc). As a result of the newly modified strategy employed by the Lick Observatory SN Search, a sequence of filtered images was obtained starting 161 s after discovery. Utilizing recent models describing the interaction of SN ejecta with a companion star, we rule out a ~1 M_Sun companion for half of all viewing angles and a red-giant companion for nearly all orientations. SN 2012cg reached a B-band maximum of 12.09 +/- 0.02 mag on 2012 June 2.0 and took ~17.3 d from explosion to reach this, typical for SNe Ia. Our pre-maximum brightness photometry shows a narrower-than-average B-band light curve for SN 2012cg, though slightly overluminous at maximum brightness and with normal color evolution (including some of the earliest SN Ia filtered photometry ever obtained). Spectral fits to SN 2012cg reveal ions typically found in SNe Ia at early times, with expansion velocities >14,000 km/s at 2.5 d past explosion. Absorption from C II is detected early, as well as high-velocity components of both Si II 6355 Ang. and Ca II. Our last spectrum (13.5 d past explosion) resembles that of the somewhat peculiar SN Ia 1999aa. This suggests that SN 2012cg will have a slower-than-average declining light curve, which may be surprising given the faster-than-average rising light curve.

An analytical approach for physical modeling of hot-carrier induced degradation

We develop an analytical model for hot-carrier degradation based on a rigorous physics-based TCAD model. The model employs an analytical approximation of the carrier acceleration integral (calculated with our TCAD approach) by a fitting formula. The essential features of hot-carrier degradation such as the interplay between single-and multiple-electron components of Si–H bond dissociation, mobility degradation during interface state build-up, as well as saturation of degradation at long stress times are inherited. As a result, the change of the linear drain current can be represented by the analytical expression over a wide range of stress conditions. The analytical model can be used to study the impact of device geometric parameters on hot-carrier degradation.

The Study on Foliar Micromorphology of Hippobromus pauciflorus Using Scanning Electron Microscope

Foliar micromorphology of Hippobromus pauciflorus (L.f.) Radlk (Sapindaceae) was investigated by scanning electron microscope examination. The leaves were characterized by anisocytic stomata which were found only on the abaxial surface. The leaves have long unicellular non-glandular trichomes which were distributed over the mid rib and densely populated at the edges of the upper and lower surfaces. Crystal deposits were also observed on the abaxial surface of the leaves. Energy dispersive X-ray spectroscopy SEM of the crystals showed predominant mineral components of Na, Al, Si, K and Ca ions. These micro (Si, Na and Al) and macro (K and Ca) elements are very essential to plant growth. Their presence in the trichomes could contribute to the mechanical stability of the leaf appendages.

Nanosilver-Coated Porous SiC-Si3N4Composite Using Microwave-Assisted Process

Using a novel microwave-assisted process, nano-Ag-coated continuous porous SiC-Si 3 N 4 substrate was fabricated from a solution containing AgNO 3 salts and ethylene glycol. The detailed microstructure of the fabricated substrate was investigated depending on the amount of AgNO 3 salts in the starting solution and the microwave irradiation time. From a solution containing 0.4 g of AgNO 3 for 60 s irradiation time, the Ag nanoparticles, ∼25 nm in diameter, were homogeneously coated on the continuous porous SiC-Si 3 N 4 matrix as well as on the surface of the Si 3 N 4 whiskers. However, the Ag nanoparticles (∼15 nm) deposited from a solution containing 0.6 g of AgNO 3 for 60 s irradiation time showed maximum homogeneity and narrow size distribution. The components of Si, N, and Ag were homogeneously distributed on the deposited layer. The deposited Ag nanoparticles covered with a thin (∼2 nm), amorphous layer had nanocrystallinity and adhered well to the surface of the Si 3 N 4 whiskers.

Time-dependent density functional theory for nonlinear properties of open-shell systems

This paper presents response theory based on a spin-restricted Kohn-Sham formalism for computation of time-dependent and time-independent nonlinear properties of molecules with a high spin ground state. The developed approach is capable to handle arbitrary perturbations and constitutes an efficient procedure for evaluation of electric, magnetic, and mixed properties. Apart from presenting the derivation of the proposed approach, we show results from illustrating calculations of static and dynamic hyperpolarizabilities of small Si(3n+1)H(6n+3) (n=0,1,2) clusters which mimic Si(111) surfaces with dangling bond defects. The results indicate that the first hyperpolarizability tensor components of Si(3n+1)H(6n+3) have an ordering compatible with the measurements of second harmonic generation in SiO2/Si(111) interfaces and, therefore, support the hypothesis that silicon surface defects with dangling bonds are responsible for this phenomenon. The results exhibit a strong dependence on the quality of basis set and exchange-correlation functional, showing that an appropriate set of diffuse functions is required for reliable predictions of the first hyperpolarizability of open-shell compounds.

Speciation of the elements and compositions on the surfaces of dust storm particles: The evidence for the coupling of iron with sulfur in aerosol during the long-range transport

The speciation of the elements on the surface of the particles collected during dust storm and non-dust storm in Beijing and Inner Mongolia was studied by XPS. The major species of iron on the surface were oxides, sulfate, silicate, FeOOH and minor part sorbed on SiO2/Al2O3. Sulfate is the dominant species of sulfur on the surface. SiO2 and Al2O3 are the main components of Si and Al on the surface respectively. One of the most important findings was that the Fe(II) (FeS and FeSO4) produced could account for up to 44.3% and 45.6% of the total Fe on the surface in the aerosol sample collected at that night and next day of the “peak” time of the dust storm occurring on March 20, 2002, while Fe2(SO4)3, one of the Fe(III) species on the surface decreased from 67.1% to 49.5% and 48.0% respectively. Both S and Fe enriched on the surface of aerosol particles. Fe(II) accounted for 1.3%–5.3% of total Fe in bulk aerosol samples during dust storm. These results provided strong evidence to support the hypothesis of the coupling between iron and sulfur in aerosols during the long-range transport, which would have important impact on the global biogeochemical cycle.

A new Monte Carlo assisted approach to detector response functions

The physical mechanisms that describe the components of NaI, Ge and Si(Li) detector responses have been investigated using Monte Carlo simulation. The mechanisms described focus on the shape of the Compton edge, the magnitude of the flat continuum, and the shape of the exponential tails features. These features are not accurately predicted by previous Monte Carlo simulations. Probable interaction mechanisms for each detector response component are given based on this Monte Carlo simulation.

Kinetic Study for the Reactions of Si Atoms with SiH4

Rate constants for the reactions of Si (3P, 1D, and 1S) atoms with SiH4 have been determined using a combined laser photolysis/laser induced fluorescence technique. The reaction of Si(3P) with SiH4 is shown to proceed with a rate constant k(Si(3PJ) + SiH4) = (2.1±0.2) × 10-10 cm3 molecule-1 s-1, with no discernible pressure dependence over a pressure range of 5−20 Torr of N2 diluent. The rate constants of each triplet component of Si(3PJ=0,1,2) atoms exhibit no significant spin-orbit dependence within the experimental uncertainties. The results of the density functional theory calculations show that the reaction of Si(3P) atoms with SiH4 proceeds via a loose transition state. The Si(1D) + SiH4 reaction rate constant is determined to be (5.2 ± 0.3) × 10-10 cm3 molecule-1 s-1. The Si(1S) atom is less reactive with SiH4 than the Si(1D) atom, with an upper limit of k(Si(1S) + SiH4) = 4.7 × 10-13 cm3 molecule-1 s-1.

Surface modification without desorption: recycling of Cl on Si(100)-(2 x 1).

We demonstrate chlorine-induced modification of Si(100)-(2 x 1) under conditions where Cl is recycled rather than desorbed as SiCl2. A dimer with 2 Cl atoms, 2SiCl, converts to SiCl2+Si, allowing the bare Si atom to escape onto the terrace. At temperatures below the desorption threshold, the SiCl2 unit decays through Cl diffusion, allowing the second Si atom to escape. The result is a dimer vacancy, terrace regrowth structures, and Cl that is able to participate in another pitting event. Access to this unexpected roughening pathway is controlled by the Cl concentration and temperature. This previously overlooked process represents an important component of Si(100) surface processing.

Structure and interfacial properties of nanocrystalline aluminum/mullite composites

Using the mechanical attrition method, nanocrystalline aluminum powder with grain size of 27 nm, and submicrometer-sized mullite particles with grain size of 67 nm were obtained. The ultrafine mullite particle reinforced nanocrystalline aluminum composite samples were fabricated by consolidation using hot isostatic pressing at pressures up to 1.5 GPa, and temperatures ranging from 300 to 450 °C. The density of the nanocomposite sample with 20% mullite by weight was 96.5% of the theoretical value. The microstructure of the nanocrystalline aluminum/mullite composite samples was investigated using X-ray diffraction and transmission electron microscopy analyses. The atomic components in the interface between mullite particle and aluminum matrix were determined using energy dispersive X-ray spectrometry. The microscopy investigations showed that the mullite particles tended to agglomerate, resulting in significant voids mainly existing around the large mullite particles and a lower-than theoretical density. The components of Al, O and Si changed nearly linearly over the interface range, indicating that the interface was formed by atomic diffusion. Atomic diffusion played an important role in the aluminum wetting the mullite particles.