Thermal imaging of microwave fields inside the surfatron and the microwave plasma torch

A new method is introduced for imaging microwave fields, such as those found in microwave-plasma support structures. The method relies upon the darkening that such fields cause in heat-sensitive paper, such as that used in some telefax printers. With this new method, the microwave-frequency electric fields inside two microwave-plasma support structures, the surfatron and the microwave plasma torch, have been measured and subsequently imaged in three dimensions. The images reveal that the surfatron and microwave plasma torch have different operational behavior. As expected, the electric field strength inside the surfatron exponentially falls off down the length of the quartz plasma tube. The field inside the microwave plasma torch initially diminishes, but then increases in strength towards the end of the tube. An aerosol was introduced into the surfatron to observe the effect of water vapor on the electric field strength and distribution. The exponential axial decay of the electric field in the ‘dry’ surfatron plasma, characteristic of a surface wave propagating down a quartz plasma tube, is extended further down the quartz tube in the ‘wet’ plasma. A drop in plasma conductivity is likely the origin of the elongated propagation of the surface wave.     

微波在高分子中的应用

作为一种新型高效的加热方式，微波技术为高分子合成及应用提供了一种新思路，它的应用可大大降低反应的时间与能耗，提高各种反应的速率、收率和选择性，正日渐成为人们关注的热点。本文综述了近年来微波技术在高分子材料，特别是功能高分子材料合成中的应用，以及微波固化与传统热固化的同异，指出微波固化高效均匀，可使固化反应加速，降低固化时间，产品的物理和机械性能优异，可在更广的范围内替代热固法。     

Atomic-scale rectification at microwave frequency

Microwave of known amplitude and frequency, irradiating the junction of a low temperature scanning tunneling microscope, was found to induce a dc signal. This rectification current is spatially localized and exhibits chemical sensitivity at the atomic scale. Dependence of the rectification current on the sample bias voltage reveals spin splitting in the electronic state of a single Mn atom and vibrations of single MnCO molecule. These results demonstrate the feasibility of atomic scale nonlinear spectroscopy and the potential for the detection of resonance phenomena excited with a spatially extended electromagnetic wave.     

The microwave spectrum of tellurophene

The microwave spectrum of tellurophene, C₄H₄Te, has been recorded between 8 and 27 GHz. The rotational constants obtained from least-squares fitting of low-J lines are:

Figures in parentheses are uncertainties in last place of decimal (95% confidence limit). Corresponding inertial defects are 0.094 (7), 0.095 (6) and 0.097 (10) amu A² respectively, indicating the essential planarity of the molecule.Stark shift measurements correspond to a dipole moment of μ_a = 0.619 x 10^?30 C m (0.186 D).An approximate structure, based on bond lengths of CC and CH bonds adopted from related molecules, implies that r (Te - C) = 205.5 pm and ? C (5) TeC (2) = 82.53°.     

Development and Optimization of Methylcellulose-Based Nanoemulgel Loaded with Nigella sativa Oil for Oral Health Management: Quadratic Model Approach

The present study aimed to develop a local dental nanoemulgel formulation of Nigella sativa oil (NSO) for the treatment of periodontal diseases. NSO purchased from a local market was characterized using a GC–MS technique. A nanoemulsion containing NSO was prepared and incorporated into a methylcellulose gel base to develop the nanoemulgel formulation. The developed formulation was optimized using a Box–Behnken statistical design (quadratic model) with 17 runs. The effects of independent factors, such as water, oil, and polymer concentrations, were studied on two dependent responses, pH and viscosity. The optimized formulation was further evaluated for droplet size, drug release, stability, and antimicrobial efficacy. The developed formulation had a pH of 7.37, viscosity of 2343 cp, and droplet size of 342 ± 36.6 nm. Sustained release of the drug from the gel for up to 8 h was observed, which followed Higuchi release kinetics with non-Fickian diffusion. The developed nanoemulgel formulation showed improved antimicrobial activity compared to the plain NSO. Given the increasing emergence of periodontal diseases and antimicrobial resistance, an effective formulation based on a natural antibacterial agent is warranted as a dental therapeutic agent.     

Time-dependent density functional theory based on a noncollinear formulation of the exchange-correlation potential

In this study we have introduced a formulation of time-dependent density functional theory (TDDFT) based on a noncollinear exchange-correlation potential. This formulation is a generalization of conventional TDDFT. The form of this formulation is exactly the same as that of the conventional TDDFT for the excitation energies of transitions that do not involve spin flips. In addition, this noncollinear TDDFT formulation allows for spin-flip transitions. This feature makes it possible to resolve more fully excited state spin multiplets, while for closed-shell systems, the spin-flip transitions will result in singlet-triplet excitations and this excitation energy calculated from this formulation of TDDFT is exactly the same as that from ordinary TDDFT. This formulation is applied to the dissociation of H(2) in its (1)Sigma(g) (+) ground state and (1)Sigma(u) (+) and (3)Sigma(u) (-) excited states with (3)Sigma(u) (-) (M(s)=+1) as the reference state and the multiplets splitting of some atoms.     

The microwave spectrum of selenoformaldehyde

The microwave spectra of the four major isotopic species of the unstable molecule selenoformaldehyde have been assigned. The limited number of isotopic variants yields the following structure: r(CSe) = 175.9 pm, ∠(HCH) = 120.4° and r(CH) assumed to be 109 pm. The dipole moment is 1.41 ± 0.01 D.     

Fluids in porous media. III. Scaled particle theory

Based on a new and consistent formulation of scaled particle theory for a fluid confined in random porous media, a series of new approximations are proposed and one of them gives equations of state with excellent accuracy for a hard sphere fluid adsorbed in a hard sphere or an overlapping hard sphere matrix. Although the initial motivation was to remedy a flaw in a previous formulation of the scaled particle theory for a confined fluid, the new formulation is not a trivial and straightforward correction of the previous one. A few conceptual and significant modifications have to be introduced for developing the present formulation.     

Cross-metathesis assisted by microwave irradiation

Microwave irradiation effectively accelerates cross-coupling metathesis reactions between deactivated olefins. Reactions have been carried out with the phosphine-free Hoveyda-Grubbs catalyst and the "second generation Grubbs' catalyst." While there have been reports that a "microwave effect" is observed in various transformations, the accelerations we observe are due to the efficient and rapid heating and increased pressure in the microwave apparatus.     

Study of the physicochemical properties of tulobuterol dry syrups using taste and smell sensors

The purpose of the present study was to evaluate the taste and smell of Tulobuterol Dry Syrup (TB-DS) in its original form (formulation A) and generic form (formulations B and C) by means of gustatory sensation tests and taste and smell sensors. In addition, the physicochemical properties of the syrups in a solid state were compared. Evaluation of sweetness with a powdered sample revealed significant differences between formulation A and formulation B and between formulation B and formulation C. In contrast, the results of principal component analysis (PCA) with a taste sensor revealed differences in principal component 1 (PC 1) among formulations A, B, and C. Smell sensor measurement of powdered samples revealed differences in products in terms of only PC 1, but these results were not related to the results of gustatory sensation testing with a smell sensor. Measurement of particle size distribution and scanning electron microscopy revealed differences in the particle diameter and particle surface shape for each product. Formulation B had the strongest absorption in the near-infrared spectrum, followed by formulation A and then formulation C. Accordingly, differences in preparations were presumably caused by variations in manufacturing specifications, such as types of additives and their content and coating methods used. In other words, the characteristics of each product were revealed by evaluation of their physical properties, sensing of taste and smell, and human gustatory sensation tests.     

Study of the Effect of the Interaction Between Kaolin and Surfactant Blend (AOS: APG C12) on the Solubility,Dispersibility, and Wetting Property of the Pesticide Granule

The extensive use of pesticides in agriculture in particular herbicides is a serious environmental threat. There is an urgent need to develop pesticide formulation that combines optimum bioactivity and minimum dosage. In the present article an attempt has been made to design granular formulation of one of the most commonly used herbicide, atrazine (AT). This potent herbicide along with kaolin as the carrier and suitable clay modifiers can be thought as one of the potential way of formulation keeping in view the desired dosage and bioavailability of the same. The process of granule formulation was carried out using the principle of rapid mix granulation. These granule formulations were then compared with the other formulation where the clay was not modified with the help of parameters such as dissolution rate, dispersion stability and wetting time. The study reveals a very positive effect of clay modifications on granules in terms of above mentioned quality parameters.     

HPLC analysis of juzen-taiho-to and its variant formulations and their antimetastatic efficacies.

Our previous study demonstrated that the oral administration of Juzen-taiho-to resulted in a significant inhibition of the liver metastasis of colon 26-L5 cells as compared with the untreated control, without side effects. We attempted to investigate the relationship between the HPLC pattern (referred to as the fingerprint) of the formulation and its component crude drugs and the inhibition of tumor metastasis in order to obtain the optimal efficacy and constant quality of the formulation. Two Juzen-taiho-to formulations (batches #1 and #2), which were individually prepared using the same 10 crude drugs and the same preparation procedure, showed similar anti-metastatic effects and absorbance patterns by HPLC analysis. Some variant formulations of Juzen-taiho-to, in which one crude drug was substituted with other crude drugs from different sources or places of origin, exhibited reduced efficacy as compared with the original formulation, as well as differences in the fingerprint pattern compared with the original formulation. Juzen (Naimo-Ogi-->Kibana-Ogi), a variant formulation with the substitution of Astragali radix of a different origin and place of harvest, showed significant inhibition of the liver metastasis of tumor cells and a HPLC fingerprint pattern similar to that of the original formulation. Thus, HPLC fingerprint analysis of Kampo medicines may provide a useful basis for obtaining their optimal efficacy as well as constant quality of the formulation, although it has some problems and limitations, such as detectability by and sensitivity to UV absorbance.     

Dielectric spectroscopy at microwave frequencies

A method is described which is capable of measuring the dielectric properties of liquids as a continuous function of frequency over the range 10 MHz to 18 GHz; an evaluation is made of its performance over the frequency range up to 4.2 GHz. The method described has substantial advantages in ease of operation and evaluation of results over the conventional “spot” frequency and time-domain spectrometer techniques.     

Methane dimerization via microwave plasmas

Methane can be converted to ethane and ethylene in a microwave plasma reactor at pressures from 10 to 100 mm Hg. The total methane conversion has a linear correlation with power ? (45 + pressure)/flow and can be as high as 90%. The conversion of methane to ethylene varies from 0 to 11%. It reaches a maximum at a value of Power ? (45 + Pressure)/Flow of 2200 W?mm Hg?s/mL. The energy efficiency of driving this thermodynamically unfavourable reaction is 2%.     

The Effects of Formulation on Imidacloprid Dissipation in Grapes and Vine Leaves and on Required Pre-Harvest Intervals under Lebanese Climatic Conditions

In this study, imidacloprid, a systemic insecticide, currently having a specified European Commission MRL value for vine leaves (2 mg kg⁻¹), was applied on a Lebanese vineyard under different commercial formulations: as a soluble liquid (SL) and water dispersible granules (WDG). In Lebanon, many commercial formulations of imidacloprid are subject to the same critical good agricultural practice (cGAP). It was, therefore, important to verify the variability in dissipation patterns according to matrix nature and formulation type. Random samplings of grapes and vine leaves were performed starting at 2 days until 18 days after treatment. Residue extractions were performed according to the QuEChERS method and the analytical determination using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS). The SL formulation yielded significantly higher initial deposit than the WDG formulation on grapes and vine leaves. The formulation type did not significantly affect the dissipation rates; the estimated half-lives in grapes and vine leaves were 0.5 days for all imidacloprid formulations. No pre-harvest intervals were necessary on grapes. PHIs of 3.7 days for the SL formulation and 2.8 days for the WDG formulation were estimated on vine leaves. The results showed that the type of formulation and the morphological and physiological characteristics of the matrix had an effect on the initial deposits, and thus residue levels, but not on the dissipation patterns.     

Random sequential adsorption of line segments with a finite jamming limit

The traditional formulation for random sequential adsorption (RSA) of line segments onto a plane does not possess a jamming limit; there is always space for a 1D object on a 2D plane. We propose a qualitatively different RSA formulation for line segments which does lead to a finite jamming limit, 1.5707+/-0.0001 segments per square one segment on the side. To our knowledge, this is the first appearance of the number pi in the jamming limit of an RSA problem. This RSA formulation can be applied to adsorption of rigid, very high aspect ratio rods on a flat surface. These rods are not well modeled by the traditional RSA formulation. As an example of such a problem we describe the deposition of carbon nanotube-DNA hybrids on a surface and show that our theoretical formulation is consistent with experimental results.     

Microencapsulation Preservation of the Stability and Efficacy of Citrus Grandis Oil-Based Repellent Formulation against Aedes aegypti during Storage

Essential oils have been widely used as an active ingredient in mosquito repellent products. However, essential oils are highly unstable and prone to degradation when exposed to the environment during storage. Microencapsulation techniques help to maintain the stability of molecules in essential oils that are sensitive to environmental stress, and therefore improve shelf life. In this study, the physical stability and efficacy of a repellent formulation consisting of encapsulated Citrus grandis essential oil (CGEO) were evaluated under different storage conditions over a 12-month period by comparing the formulation with a non-encapsulated formulation. The formulations were both stored under two different storage conditions, i.e., 25 ± 2 °C/60% ± 5% relative humidity (RH) and 40 ± 2 °C/75% RH ± 5%, for 12 months. Droplet size, zeta potential, and pH value were measured after 1, 6, and 12 months of storage to determine their stability. For the study of efficacy, each formulation was tested against Aedes aegypti under laboratory conditions. We found that the microencapsulated formulation’s physical characteristics showed insignificant changes as compared with the non-encapsulated formulation during storage. The microencapsulated formulation demonstrated better repellent effects, sustaining high protection (>80%) for 4 more hours of exposure after 12 months of storage as compared with the non-encapsulated formulation that demonstrated high protection for only an hour post application. Microencapsulation helped to preserve the stability of the formulation, which resulted in high protection being maintained for over 12 months of storage.