Te Source Research Articles

Poligami: Berdasarkan Konsep Keadilan dan Teori Limit Muhammad Syahrur

The discourse of polygamy is a topic that reaps the pros and cons among the Ulama’ and becomes a hot topic of discussion at the community level. Full attention of Islam regarding polygamy is not merely done without conditions, but Islam stipulates polygamy on the condition that is fair and there are restrictions on the number of wives. For his reason, reseaechers are interested in conducting deeper research on the concept of justice of polygamy practices which are still a topic of debate among the public based on the limit theory by Muhammad Syahrur. This research uses a critical descriptive research model using a methodological comparative study approach to analyze problems using the limit theory put forward by Muhammad Syahrur. This type of research is library research. Te source of this research is obtained from two legal materials, namely premier and secondary. This research uses isis analysis technique to find data to adjust the object to be studied by focusing on criticism. So that the results found that Syahrur argues that polygamy must be implemented when there has been a probem in society, but also must leave the practice when no problem is found. The concept of the limit theory put forward by heading the two conditions, including the first, namely that the second, third, or fourth wife is a widow who has an orphan, than the second is the fear of not being able to be fair to the orphan, as stated in Surah An-Nisa’ verse 3.

A model of radiofrequency and plasma coupling for compact ion sources and design

Inductive coupling of radiofrequency power to plasma is a complicate process, since it depends from the density of plasma itself, because ionization is a chain reaction process, and, at low density a capacitive coupling may mix with inductive coupling (with no Faraday screen). Plasma temperature Te , density ne and vector potential are closely coupled, giving nonlinear and singular systems of Partial Differential equations, which require slow iterative solutions, motivating the consideration of a 2D model, also as rapid design and first approximation tool. Plasma conductivity and heating depend on collision rate, which includes also the so-called stochastic collisions (mainly electron collisions with walls), proportionally more important at low gas density ng . Conductivity is also affected by static and radiofrequency magnetic fields; results for skin depth and stochastic collision estimates are reported. The transport of Te and ne inside source can be controlled by a magnetic filter B f . Considering a 5 cm radius H- ion source as example, solution of ne and Te are reported as a function of filter strength B fa, applied rf power and wall status; solver convergence methods andkey plasma observables are briefly discussed. Due to small dimension, a filter strength B fa in the order of 8 mT is needed to achieve electron temperature lower than 2 eV (for negative ion production) at extraction.

The synthesis of bismuth telluride nanowires with a high aspect ratio via precise regulation of growth rates

It is challenging to obtain one-dimensional nanowires with a high aspect ratio. Herein, we developed a controllable hydrothermal method to synthesize single-crystalline bismuth telluride (Bi2Te3) nanowires with a high aspect ratio. The effects of growth conditions including template, temperature, surfactant polyvinyl pyrrolidone (PVP) dosage, and pH value on the aspect ratio of Bi2Te3 nanowires were studied. The results show that Te nanowire templates not only support the epitaxial growth but also supply the Te source of Bi2Te3 nanowires. The reaction temperature, surfactant PVP, and pH were carried out to adjust the nucleation and diffusion rates of Bi and Te, thus controlling the growth rates of Bi2Te3 nanowires. The obtained Bi2Te3 nanowires have an aspect ratio of up to 100 (length of 7 µm and width of 70 nm).

Unusual Red Light Emission from Nonmetallic Cu2Te Microdisk for Laser and SERS Applications

AbstractPhysical characteristics of Cu2Te are poorly investigated due to limited Te sources available and unclear atomic positions of crystal structure. Herein, hexagonal Cu2Te microdisks are successfully prepared via chemical vapor deposition procedure using GaTe as Te source. The epitaxial growth mechanism of the Cu2Te hexagonal structures with the orthorhombic phase is rationalized by proposed layer‐over‐layer growth model. The photoluminescence (PL) spectrum of Cu2Te microdisks shows a new red emission band in addition to usual infrared light emission due to Cu deficiency. Single Cu2Te microdisk operates as an optical microcavity supporting whispering gallery modes for red lasing around 627.5 nm. This Cu2Te microdisk microcavity exhibits a high quality factor of 1568 and a low lasing threshold of 125 kW cm−2 at room temperature. Meanwhile, Cu2Te microdisks have been exhibited as an ideal platform for surface enhanced Raman scattering (SERS) eliminating drawbacks of noble metal substrates with detection limitation to nanomolar level and an enhancement factor of ≈1.95 × 105. Hexagonal Cu2Te microdisks turn out to be an efficient microcavity for red lasing and low‐cost nonmetallic SERS substrates, opening potential applications in photonics and biological detection of aromatic molecules.

Facile synthesis of stable CdTe/CdS QDs using dithiol as surface ligand for alkaline phosphatase detection based on inner filter effect

Alkaline phosphatase (ALP) is a universal and important hydrolase that has been proved to be associated with several diseases. Herein, a simple and effective method was proposed for ALP detection based on the inner filter effect of p-nitrophenol (pNP) on the fluorescence of CdTe/CdS quantum dots (QDs). For the preparation of CdTe/CdS QDs, Na2TeO3 was used as the Te source, and dithiol as the S source and surface ligand. The as-prepared CdTe/CdS QDs show good fluorescence properties, such as high quantum yield (∼80%), and good chemical/photo-stability. pNP is a hydrolysate of p-nitrophenol phosphate disodium salt under the catalysis of ALP, which could effectively quench the fluorescence of QDs due to the absorption spectra of pNP overlaps well with the excitation spectra of the CdTe/CdS QDs. Therefore, the prepared CdTe/CdS QDs could be applied for ALP detection. A good linear relationship ranging from 2.2 to 220 U/L was obtained with the limit of detection as low as 0.34 U/L. In addition, this method was successfully applied for the assay of ALP in human serum with the satisfactory results.

The effects of Sn:Te ratio on optical properties of SnTe NPs

The effects of Te source concentration on morphology, structural, and optical properties of the SnTe nanoparticles (NPs) were investigated. The SnTe NPs were synthesized by a simple, cost-effective, and fast co-precipitation method. X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images of the samples indicated that, crystallite and particle size of the NPs were changed by changing of Te source concentration. Fourier-transform infrared spectroscopy (FTIR) results also revealed that, some new vibration modes were appeared by varying of Te source concentration. Ultraviolet-visible-near infrared (UV-Vis-NIR) and room temperature photoluminescence (PL) spectroscopy results showed that, Te source concentration caused a big change in optical properties of the NPs. The UV–Vis–NIR results indicated that, the absorption peaks of the samples were placed in the NIR region. The PL results of the samples included several defect energy levels that performed violet, green, and red emissions. Characterization of the pure NPs by PL with different excitation power showed that, the violet and green emissions were from an alloy of oxide layer and SnTe that was formed on the surface of the NPs. On the other hand, the red emission was from donor-acceptor pair (DAP).

Phase stability in MoTe2 prepared by low temperature Mo tellurization using close space isothermal Te annealing

In this work, we used isothermal close space (ICS) Te annealings in pure H2 atmosphere for the tellurization of Mo oxide thin films. Differently to previous open tube tellurization annealings, ICS is expected to provide a higher Te vapor pressure because the chamber containing the Te source and the substrate is very small and semi-closed. Then, we used a relatively low temperature of 500 °C at which, according to the phase diagram, 2H phase should be stable. However, we observed that, in all cases, Mo oxide initially transformed to 1T′ before reaching the equilibrium 2H phase. Highly oriented MoTe2 films with the [001] direction perpendicular to the surface were obtained in all samples. On the other hand, according our X-ray photoelectron spectroscopy measurements, we report shifts of 0.38/0.27 eV in the 3d emission of Te/Mo between the two different phases which probably have a chemical origin.

A portable RGB sensing gadget for sensitive detection of Hg2+ using cysteamine-capped QDs as fluorescence probe

A facile one-pot method was proposed to synthesis cysteamine capped CdTe QDs with a high quantum yield 30%. In the synthesis process, nitrogen protection, ultrasonic treatment, and light irradiation were unnecessary. Additionally, potassium tellurite was used instead of Te powder as Te source, avoiding of the time-consuming Te powder dissolution process. The prepared QDs were found to be Hg2+ sensitive. The detection linear range for Hg2+ was from 5 to 300nM, and the detection limit was calculated to be 1nM. The detection mechanism was mainly ascribed to the electron transfer from cysteamine capped QDs to Hg2+, resulting in a fluorescence quenching phenomenon. In addition, we developed a portable RGB sensing gadget with the QDs as fluorescence probe for Hg2+ detection, and the linear range was from 5 to 200nM. Furthermore, the gadget was applied for Hg2+ detection in tap water sample. The results showed that the average recoveries in real tap water sample were in the range from 97.2% to 115.3%, which indicated that accuracy and precision were satisfactory for practical application requirements.

Phosphine-free synthesis of high-quality CdTe quantum dots: The combination of TeO2-dodecanethiol and oleylamine as Te precursor

Currently, the synthesis of CdTe quantum dots (QDs) in organic phase has basically involved costly and air-sensitive reagents such as alkylphosphines, making a more economical approach desirable. Here, a phosphine-free approach has been developed to prepare CdTe QDs, in which TeO2 dissolved in 1-dodecanethiol (DT) was employed as the Te source. The obtained QDs were highly luminescent and exhibited desirable size-tunability and narrow size distribution. More importantly, oleylamine (OLA), the specific solvent in this method, has been found to be crucial for TeO2-DT to provide reactive Te species for the formation of CdTe. These results suggest that the combination of TeO2-DT and OLA should be an efficient Te precursor for the preparation of colloidal tellurides.

High performance as-grown and annealed high band gap tunnel junctions: Te behavior at the interface

The performance of n+-InGaP(Te)/p+-AlGaAs(C) high band gap tunnel junctions (TJ) is critical for achieving high efficiency in multijunction photovoltaics. Several limitations for as grown and annealed TJ can be attributed to the Te doping of InGaP and its behavior at the junction interface. Te atoms in InGaP tend to get attached at step edges, resulting in a Te memory effect. In this work, we use the peak tunneling current (Jpk) in this TJ as a diagnostic tool to study the behavior of the Te dopant at the TJ interface. Additionally, we used our understanding of Te behavior at the interface, guided by device modeling, to modify the Te source shut-off procedure and the growth rate. These modifications lead to a record performance for both the as-grown (2000 A/cm2) and annealed (1000 A/cm2) high band gap tunnel junction.

On-Body Antenna Parameters

Within the scope of on-body communications, an approach is presented which is capable to describe the radiated on-body field of arbitrarily shaped antenna structures. The method is based on a segmentation of the excited current distribution on the antenna body by a finite number of small electric dipoles. To consider the presence of the human body, which affects the underlying radiation mechanism significantly, the model is implemented by the use of the Norton surface wave theory. Based thereon, a method is presented to model the on-body far field of an antenna by two equivalent electric dipoles: 1) a TM and 2) a TE source. Based on this assumption, the directivity and the effective antenna area are defined for on-body propagation scenarios. The radiation characteristic of body worn antennas is discussed in terms of their radiation characteristic using the example of tilted half-wave dipoles and a planar inverted-F antenna. The last part of the study discusses a pathloss model which is calculated from the underlying antenna parameters. Numerical full-wave simulations, based on the FDTD method, and measurements in an anechoic chamber, verify the results.

PEDOT:PSS film: a novel flexible organic electrode for facile electrodeposition of dendritic tellurium nanostructures

In the present study, flexible organic poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films were employed as working electrodes for the facile electrodeposition of tellurium (Te). Dendritic Te nanostructures were successfully deposited at a current of 8 mA/cm2 for 700 s at 25 °C, using Na2TeO3 as the Te source and HNO3 as the electrolyte. The phase and morphology of the resulting dendritic nanostructures were characterized by X-ray diffraction, energy-dispersive spectrometry, and scanning electron microscopy. It was found that the deposition temperature had a remarkable influence on the morphologies of the samples. A certain concentration of HNO3 was indispensable in the formation of dendritic Te nanostructures. High deposition current density promoted the formation of dendritic Te nanostructures and the morphologies could be affected by the Na2TeO3 concentration. It is expected that flexible organic PEDOT:PSS film working electrodes may provide a facile and general method for synthesizing materials with a wide array of applications.

Synthesis of AS1411-aptamer-conjugated CdTe quantum dots with high fluorescence strength for probe labeling tumor cells.

In this paper, we report microwave-assisted, one-stage synthesis of high-quality functionalized water-soluble cadmium telluride (CdTe) quantum dots (QDs). By selecting sodium tellurite as the Te source, cadmium chloride as the Cd source, mercaptosuccinic acid (MSA) as the capping agent, and a borate-acetic acid buffer solution with a pH range of 5-8, CdTe nanocrystals with four colors (blue to orange) were conveniently prepared at 100 °C under microwave irradiation in less than one hour (reaction time: 10-60 min). The influence of parameters such as the pH, Cd:Te molar ratio, and reaction time on the emission range and quantum yield percentage (QY%) was investigated. The structures and compositions of the prepared CdTe QDs were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, selective area electron diffraction, and X-ray powder diffraction experiments. The formation mechanism of the QDs is discussed in this paper. Furthermore, AS1141-aptamer-conjugated CdTe QDs in the U87MG glioblastoma cell line were assessed with a fluorescence microscope. The obtained results showed that the best conditions for obtaining a high QY of approximately 87% are a pH of 6, a Cd:Te molar ratio of 5:1, and a 30-min reaction time at 100 °C under microwave irradiation. The results showed that AS1141-aptamer-conjugated CdTe QDs could enter tumor cells efficiently. It could be concluded that a facile high-fluorescence-strength QD conjugated with a DNA aptamer, AS1411, which can recognize the extracellular matrix protein nucleolin, can specifically target U87MG human glioblastoma cells. The qualified AS1411-aptamer-conjugated QDs prepared in this study showed excellent capabilities as nanoprobes for cancer targeting and molecular imaging.

Simple one-pot aqueous synthesis of CdHgTe nanocrystals using sodium tellurite as the Te source

In this work, we systematically investigated the one-pot aqueous synthesis conditions of CdHgTe nanocrystals (NCs) using sodium tellurite (Na2TeO3) as the Te source, and found that the added content of Hg2+ and the initial pH value of reaction solutions significantly affected the photoluminescence quantum yield (PL QY) of alloyed CdHgTe NCs. When the concentration of Cd was 1.0mmolL−1, the mole ratio of Cd/Te/Hg/MPA was 1:0.5:0.05:2.4, and the initial pH value of the reaction solution was about 8.78, the PL QY of as-prepared CdHgTe NCs was up to 45%. Characterization by HRTEM and XRD confirmed the crystalline nature of CdHgTe NCs. Compared to other synthetic approaches of CdHgTe NCs, our experimental results indicate that Na2TeO3 could be an attractive alternative Te source to directly synthesize CdHgTe NCs in aqueous media.

Fabrication of NiTe films by transformed electrodeposited Te thin films on Ni foils and their electrical properties

Tellurium (Te) source of compact nickel telluride (NiTe) thin film was prepared by simple electrochemical deposition method.

EFFECT OF THE STRUCTURE OF ISOMERS OF MERCAPTOVALERIC ACID ON OPTICAL PROPERTIES OF CdTe QUANTUM DOTS

4-Mercaptovaleric acid (4MVA) and 3-mercaptovaleric acid (3MVA), two branched isomers of 5-mercaptovaleric acid (MVA), were designed and synthesized. They were used as capping agents in the aqueous synthesis of CdTe quantum dots (QDs) by a modified hydrothermal method with sodium tellurite as Te source. Compared with MVA- CdTe , either 4MVA-QDs or 3MVA-QDs exhibited higher fluorescent quantum yield (QY) and sharper absorption peak, which confirmed the superiority of using branched mercapto acids in the aqueous synthesis of QDs for improved optical properties. The fluorescence of QDs capped with 4MVA was higher than that of QDs capped with 4-mercaptobutyric acid (MBA) but lower than that of QDs capped with 3-mercaptobutyric acid (3MBA), which further confirmed the advantage of designing methyl side group rather than methylene group in the main chain for desired optical properties. However, the lower fluorescence, less sharp absorption peak and faster growth rate of 3MVA-QDs than that of 3MBA-QDs indicated adverse effect of side group on the aqueous synthesis of QDs if the size of side group is very bulky. Our results are helpful for selecting and designing appropriate capping agents for QDs with excellent properties.

Facile solution routes for the syntheses of GeTe nanocrystals

Solution-based synthetic routes are attractive strategies for synthesizing GeTe materials, because they have the potential to impart morphology control on the crystallites and permit liquid-based processing of films and patterned structures. Two liquid phase reaction systems for GeTe nanoparticles (NPs) have been studied using GeCl2·dioxane and trioctylphosphine-tellurium (TOP-Te) in oleylamine (OLA) as solvent and reducing agent and using GeCl2·dioxane and (Et3Si)2Te in trioctylphosphine oxide (TOPO) without the use of any reducing agent. The morphology of the GeTe powders had a strong dependence on the Te source and reaction medium. The SEM image of NPs obtained by the reaction of GeCl2·dioxane and (Et3Si)2Te reveals that with an increase in reaction time (2, 10, 15 and 30 min), the size of the NPs increases and their shape becomes uniform. However, it is interesting to observe that after 30 min, the morphology of the nanoparticles was maintained even after longer reaction times i.e., the duration of heating had no pronounced influence on the size and morphology of the nanocrystals after a particular period of time. Reaction with TOP-Te leads to the formation of irregular GeTe nanocrystals through the so called Ostwald-ripening process. However, with (Et3Si)2Te as Te source, a ligand exchange reaction mechanism has been proposed leading to the formation of well-dispersed GeTe nanoparticles of uniform shape.

Regulating properties of quantum dots: effect of methyl side groups of mercapto acids

A series of mercapto acids with and without methyl side groups, namely 3-mercaptopropanoic acid (MPA), 4-mercaptobutyric acid (MBA), 5-mercaptovaleric acid (MVA), 3-mercaptobutyric acid (3MBA), 3-mercaptoisobutyric acid (MIBA), 3-mercapto-2-methylbutyric acid (MMBA) and 3-mercapto-2,2-dimethylpropanoic acid (MDMPA), were synthesized and used as capping agents to prepare CdTe quantum dots (QDs) by a modified hydrothermal method with Na2TeO3 as Te source. By comparing the growth rate, size distribution, fluorescence and solution stability of QDs capped with these mercapto acids, the effect of the position and amount of the methyl side groups of mercapto acids in the aqueous synthesis of CdTe QDs was revealed. The use of branched mercapto acids with one methyl side group (3MBA and MIBA) was superior to obtain QDs with narrow size distribution, strong fluorescence and good long-term solution stability than the use of linear mercapto acids (MPA, MBA and MVA) whereas the use of branched mercapto acids with two methyl side groups (MMBA and MDMPA) was not equally successful. Among these mercapto acids, 3MBA-QDs had the strongest fluorescence and MIBA-QDs had the narrowest size distribution. Our results are helpful for synthesizing QDs with good properties by selecting and designing appropriate capping agents.

Synthesis of Mercaptosuccinic Acid/MercaptoPolyhedral Oligomeric Silsesquioxane Coated Cadmium Telluride Quantum Dots in Cell Labeling Applications

An aqueous synthesis method to obtain highly luminescent cadmium telluride nanocrystals is described. We have shown water-soluble semi-conductor quantum dots with high photoluminescence quantum yield have great potential for biological applications. The spectral properties of these nanocrystals can be easily tuned according to their particle size to yield multicolours simultaneously by a single excitation light source. A stable precursor material sodium tellurite is utilised instead of the traditional oxygen sensitive NaHTe or H2Te as Te source. We have introduced mercaptosuccinic acid and propylisobutyl polyhedral oligomeric silsesquioxane nanoparticles as novel capping agents to stabilize the nanocrystals, synthesized in borate-citrate buffering system. Inclusion of propylisobutyl polyhedral oligomeric silsesquioxane nanoparticles in the capping procedure showed enhanced stability and biocompatibility. The presence of mercaptosuccinic acid/propylisobutyl polyhedral oligomeric silsesquioxane coatings was confirmed by Fourier Transform Infrared spectroscopy and average sizes of 2-5 nm by transmission electron microscopy measurements. The functionalized and targeted quantum dots detected cancer cell death on exposure to some anticancer drugs. Studies have indicated that apoptotic cells can activate signaling pathways in dendritic cells via ligation of surface receptors. Cells treated with specific class of pro-apototic drug such as anthracyclines mount an anti-tumour immune response when introduced into mice. Apoptotic cells may be immunogenic or non-immunogenic depending on the presence of calreticulin on the plasma membrane of dying tumour cells. Here the confocal microscopy showed localization of conjugated mercaptosuccinic acid/propylisobutyl polyhedral oligomeric silsesquioxane cadmium telluride quantum dots on MCF-7 cells when exposed to cadmium ions at 50 microM, compared to coated quantum dots. We have used cadmium ions as a model drug as certain anticancer drugs (anthracyclines) induce translocation of calreticulin to the cell membrane, an indicator of apoptosis. Antibodies generated against a peptide to human calreticulin and conjugated to quantum dots detected the protein on cell membrane of stimulated cells were visualized by confocal microscopy. Stimulating natural immune response, against tumours has enormous potential to improve current regimens of cancer detection and therapy.

3-Mercaptobutyric Acid as an Effective Capping Agent for Highly Luminescent CdTe Quantum Dots: New Insight into the Selection of Mercapto Acids

CdTe quantum dots (QDs) were synthesized by a modified hydrothermal method with Na2TeO3 as the Te source. Thioglycolic acid (TGA), thiolactic acid (TLA), 3-mercaptopropionic acid (MPA), 3-mercaptobutyric acid (3MBA), 4-mercaptobutyric acid (MBA), and 5-mercaptovaleric acid (MVA) were used. Their effects on the growth and fluorescence of as-synthesized QDs were investigated: Detrimental precursor aggregation when using TGA-like molecules (TGA and l-cysteine) due to their special secondary coordination was observed and further confirmed by comparing with dl-homocysteine and N-acetyl-l-cysteine. The aggregation could be suppressed by using a bulky methyl group as a side chain to confine the carboxyl group, that is, TLA. Moreover, MPA was confirmed as a better stabilizer compared with linear TGA, MBA, and MVA probably because of its suitable balance between hydrophilicity and hydrophobicity. Accordingly, we designed and synthesized 3MBA that has the same main chain length as MPA but with a side methyl group as TLA. 3MBA-modified CdTe QDs exhibited an excellent optical property with a quantum yield of 71%, much higher than that of MPA and TGA. Preliminary results of CdSe QDs confirmed the versatility of 3MBA. Our results uncovered the possible origin of the advantages of mercapto acids with a methyl side chain and a suitable chain length.