Double Chains Research Articles

Progress in research of sulfobetaine surfactants used in tertiary oil recovery

AbstractThe synthesis of sulfobetaine surfactants and their application in tertiary oil recovery (TOR) are summarized in this paper. The synthesis of sulfobetaine surfactants was classified into three categories of single hydrophobic chain sulfobetaine surfactants, double hydrophobic chain sulfobetaine surfactants and Gemini sulfobetaine surfactants for review. Their application in TOR was classified into surfactant flooding, microemulsion flooding, surfactant/polymer (SP) flooding and foam flooding for review. The sulfonated betaine surfactants have good temperature resistance and salt tolerance, low critical micelle concentration (cmc) and surface tension corresponding to critical micelle concentration (γcmc), good foaming properties and wettability, low absorption, ultralow interfacial tension of oil/water, and excellent compatibility with other surfactants and polymers. Sulfobetaine surfactants with ethoxyl structures, hydroxyl and unsaturated bonds, and Gemini sulfobetaine surfactants will become an important direction for tertiary oil recovery because they have better interfacial activity in high‐temperature (≥90°C) and high‐salinity (≥104 mg/L) reservoirs. Some problems existing in the synthesis and practical application were also reviewed.

A Modified Quantum-Inspired Genetic Algorithm for Continuum Structural Topology Optimization

Topology optimization and quantum computing have evolved rapidly over the past three decades. Previous topological optimum design methods suffered from financial burden and mathematical complexity. To overcome these shortcomings, a modified quantum-inspired evolutionary algorithm-based topology optimization method is proposed. This nested approach combines the classic solid isotropic microstructure with the penalization method and the double chains quantum genetic algorithm to establish an integral topology optimization framework. The former is utilized to determine the search direction of design variable updating. Meanwhile, the latter ensures abundant search diversity. The validity and feasibility of the developed methodology are eventually demonstrated by several application examples. The results indicate that the proposed optimization framework is independent of initial values and can lead to optimized structures. In addition, it will be more appropriate and effective if this strategy is deployed on a quantum computer in the future.

Differentiating between the sequence of structural events on alternative pathways of folding of a heterodimeric protein.

Distinguishing between competing pathways of folding of a protein, on the basis of how they differ in their progress of structure acquisition, remains an important challenge in protein folding studies. A previous study had shown that the heterodimeric protein, double chain monellin (dcMN) switches between alternative folding pathways upon a change in guanidine hydrochloride (GdnHCl) concentration. In the current study, the folding of dcMN has been characterized by the pulsed hydrogen exchange (HX) labeling methodology used in conjunction with mass spectrometry. Quantification of the extent to which folding intermediates accumulate and then disappear with time of folding at both low and high GdnHCl concentrations, where the folding pathways are known to be different, shows that the folding mechanism is describable by a triangular three-state mechanism. Structural characterization of the productive folding intermediates populated on the alternative pathways has enabled the pathways to be differentiated on the basis of the progress of structure acquisition that occurs on them. The intermediates on the two pathways differ in the extent to which the α-helix and the rest of the β-sheet have acquired structure that is protective against HX. The major difference is, however, that β2 has not acquired any protective structure in the intermediate formed on one pathway, but it has acquired significant protective structure in the intermediate formed on the alternative pathway. Hence, the sequence of structural events is different on the two alternative pathways.

Effect of Chitosan Nanoparticles (CS-NPs) on In Vitro Regeneration Response and Production of Potato virus Y (PVY)-Free Plants of Potato

Potato virus Y (PVY) causes serious loss in the yield and quality of potatoes. The effect of chitosan nanoparticles (CS-NPs) on the regeneration response and production of PVY-free plants under in vitro conditions was studied. Murashige and Skoog (MS) medium supplemented with 0.1 mg L−1 Gibberellic acid (GA3), 0.1 mg L−1 Naphthalene acetic acid (NAA) and 500 mg L−1 malt extract was used for regeneration of plantlets from sprouts. Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA) and Reverse Transcript Polymerase Chain Reaction (RT-PCR) was used for virus indexing of the mother plant and in vitro-regenerated plantlets. Explants of PVY positive potato plants were cultured on same medium amended with 100, 200, 250, and 300 mg L−1 of (CS-NPs). Shoot regeneration decreased from 100 to 200 mg L−1 as the concentrations of antiviral (CS-NPs) up to 250 mg L−1. It was decreased with the increase in the concentration of the antiviral (CS-NPs) up to 300 mg L−1. Antiviral (CS-NPs) at the concentration of 250 mg L−1 showed a positive effect on shoot regeneration. In vitro-regenerated plantlets were virus free and tested negative in both ELISA and RT-PCR. The level of 100 mg L−1 of (CS_NPs) produced 38.8% PVY-free plants and 30.50% of cultures showed shoot regeneration. The level of 200 mg L−1 of (CS-NPs) produced 49.6% PVY-free plants while 46.8% of cultures showed shoot regeneration. The level of 250 mg L−1 of (CS-NPs) was the most effective and produced 100.0% PVY-free plants and 100.0% of cultures showed shoot regeneration. Histopathological changes simultaneously with elucidation of resistance and growth enhancement were evident in the treated plants with (CS-NPs) than those untreated control. In conclusion, (CS-NPs) treatment is an effective tool to produce PVY-free sprouts explants and has potential for producing virus-free planting material for the potato industry.

Salinity and hydraulic retention time induce membrane phospholipid acyl chain remodeling in Halanaerobium congolense WG10 and mixed cultures from hydraulically fractured shale wells.

Bacteria remodel their plasma membrane lipidome to maintain key biophysical attributes in response to ecological disturbances. For Halanaerobium and other anaerobic halotolerant taxa that persist in hydraulically fractured deep subsurface shale reservoirs, salinity, and hydraulic retention time (HRT) are important perturbants of cell membrane structure, yet their effects remain poorly understood. Membrane-linked activities underlie in situ microbial growth kinetics and physiologies which drive biogeochemical reactions in engineered subsurface systems. Hence, we used gas chromatography-mass spectrometry (GC-MS) to investigate the effects of salinity and HRT on the phospholipid fatty acid composition of H. congolense WG10 and mixed enrichment cultures from hydraulically fractured shale wells. We also coupled acyl chain remodeling to membrane mechanics by measuring bilayer elasticity using atomic force microscopy (AFM). For these experiments, cultures were grown in a chemostat vessel operated in continuous flow mode under strict anoxia and constant stirring. Our findings show that salinity and HRT induce significant changes in membrane fatty acid chemistry of H. congolense WG10 in distinct and complementary ways. Notably, under nonoptimal salt concentrations (7% and 20% NaCl), H. congolense WG10 elevates the portion of polyunsaturated fatty acids (PUFAs) in its membrane, and this results in an apparent increase in fluidity (homeoviscous adaptation principle) and thickness. Double bond index (DBI) and mean chain length (MCL) were used as proxies for membrane fluidity and thickness, respectively. These results provide new insight into our understanding of how environmental and engineered factors might disrupt the physical and biogeochemical equilibria of fractured shale by inducing physiologically relevant changes in the membrane fatty acid chemistry of persistent microbial taxa. GRAPHICAL ABSTRACTSalinity significantly alters membrane bilayer fluidity and thickness in Halanaerobium congolense WG10.

Moisture‐Resistant Chiral Perovskites for White‐Light Circularly Polarized Photoluminescence

AbstractCircularly polarized luminescence (CPL) has recently caught increasing attention owing to its widespread applications from 3D display to quantum‐based optical computation. Among various CPL‐active materials, low‐dimensional hybrid perovskites have risen to prominence, benefiting from their excellent structural flexibility and optoelectronic properties. However, the exploration of hybrid perovskites with white‐CPL remains a challenge and most of them suffer from moisture instability. Here, a pair of moisture‐resistant 1D hybrid perovskites, (R‐C5H14N2)PbBr4·H2O (1R) and (S‐C5H14N2)PbBr4·H2O (2S), are reported in which [PbBr42−]∞ double chains are surrounded by chiral cations and water molecules forming the bulk assembled quantum‐helix structures. The strong quantum confinement in these unique structures facilitates exciton self‐trapping, which further synergizes the effect of chiral cations, endowing 1R and 2S with opposite broadband yellowish white‐CPL with a luminescence dissymmetry factor (glum) of 1.8 × 10−3 and a color rendering index up to 81. Notably, the dehydrated 1R can be recovered in humid air (60% relative humidity) within a few minutes via reabsorption of water molecules, exhibiting excellent moisture resistance, which is much better than most reported hybrid perovskites. A new path is paved here to further exploration of moisture‐resistant CPL‐active materials for multifunctional applications.

Effect of Radon and Lung Cancer Risk: A Narrative Literature Review

Exposure to cigarette smoke has been known to be a major risk factor for lung cancer. Although smoking has long been considered the main cause of lung cancer, about 5 to 25% of lung cancer cases occur in non-smokers. Radon is said to be the second most important cause of lung cancer after smoking. Radon-222 is a chemical element in the form of a highly radioactive gas that comes from the decay of the parent radioactive element, uranium, which is found in the earth's crust. Inhaled radon gas can adhere to the mucosal lining of the airways and damage the airway epithelium. The process of ionizing radiation by alpha particles due to the decay of radioactive substances can cause mutations and chromosomal aberrations, severance of DNA double chains, and formation of reactive oxygen species. (ROS) that cause cell cycle changes, up-and down-regulation of cytokines, and increased production of proteins associated with cell cycle regulation and carcinogenesis. Research on radon and lung cancer has not been widely conducted in Indonesia. This literature review aims to describe radon and its effects on lung health.

Fine structure of the charge density wave in bulk VTe2

Vanadium ditelluride (VTe2) has been intensively explored to understand the charge density wave (CDW) phase and its connection to magnetic properties. Here, we conduct a systematic study to understand the fine structure of CDW via scanning tunneling microscopy (STM) combined with density functional theory (DFT) calculations. STM topograph at 79 K shows that a CDW phase in VTe2 has a stripe modulation with 3 × 1 periodicity, following the double zigzag chain of distorted Te lattices. Interestingly, the 3 × 1 CDW modulation undergoes contrast inversion between filled and empty state topographs. Atomistic features and contrast changes of CDW observed in STM are clearly reproduced in our DFT simulation images. Charge distribution calculation indicates that the spatial extension and density of Te 5p orbitals have strong variations with filled and empty states, explaining the fine structure of 3 × 1 CDW in VTe2. Our finding provides an inspiring insight to further research on the less explored electronic structure of VTe2.

Orientation simulation and image experiment for flexible biomass particle in wedge fluidization channel

Flexible biomass particles have a large proportion in food production and processing, and particle orientation is related to the quality and efficiency of food production. Thus far, the particle orientation control mechanism has rarely been revealed. In this work, Computational Fluid Dynamics–Discrete Element Method (CFD–DEM) model is presented to study the flow characteristics of tea in a wedge channel. The biomass particles are represented by a double chain bonded-sphere model. The CFD–DEM model for flexible particles is verified by image experiments. The effects of gas velocity, particle length, feeding rate, and wedge outlet diameter on particle orientation distribution are investigated and discussed. Results show that the particle orientation is slightly affected by gas superficial velocity. The proportion of particles oriented at 0–30° increases as the particle length and feeding rate increase and decreases as channel outlet diameter increases. The particles with the orientation angles of 0–10° and 0–30° are about 25% and 80%, respectively, when the channel outlet diameter is 40 mm. These findings provide great significance for the processing, storage, and transportation of tea and other biomass. • A double-chain bonded-sphere model of flexible particles is proposed. • Image experiment is designed to verify the established numerical model. • An orientation control method of flexible biomass particles is proposed. • Particle orientation is influenced by gas velocity gradient and particle length.

X-ray diffraction and Mössbauer spectroscopy study of oxoborate azoproite (Mg,Fe2+)2(Fe3+,Ti,Mg,Al)O2(BO3): an in situ temperature-dependent investigation (5 ≤ T ≤ 1650 K)

This work is devoted to an investigation of elemental composition, crystal structure and thermal expansion of natural oxoborate azoproite from the Tazheran massif (Siberia, Russia) in the temperature range 5–1650 K. Elemental composition was determined by energy-dispersive X-ray spectroscopy (EDX). Its empirical formula based on five oxygen atoms is (Mg1.81Fe2+ 0.19)∑2.00(Fe3+ 0.36Ti0.26Mg0.26Al0.12)∑1.00O2(BO3). Local environment, oxidation states and ratio of Fe atoms are determined using Mössbauer spectroscopy and compared with EDX and single-crystal X-ray diffraction (SCXRD) data. A refinement of the crystal structure from SCXRD data collected at 293 K was provided for the first time. The structure could be described both in terms of cation- and anion-centered polyhedra. It is composed of vertex- and edge-sharing metal–oxygen [MO6] n − octahedra that form extended zigzag chains along the a axis building up a framework with the [BO3]3− triangles located in its distorted trigonal channels. From the other point of view, there are double chains consisting of oxocentred [OM 4] n + tetrahedra and [OM 5] n + tetragonal pyramids forming six-membered rings with the triangles in its cavities. Four non-equivalent Mn + sites are occupied by cations as follows: M(1) (2a) and M(2) (2d) – Mg, M(3) (4g) – Mg and Fe2+, M(4) (4h) – Fe3+, Ti4+, Mg and Al3+. According to differential scanning calorimetry, low- and high-temperature powder X-ray diffraction (LT- and HT-XRD) data, Mössbauer spectroscopy and magnetometry data (5 ≤ T ≤ 1650 K), there are no phase transitions obtained in the temperature range investigated. However, some anomalies in temperature dependencies of unit-cell parameters caused by a partial Fe2+ → Fe3+ oxidation are found in the range 873–1173 K. Azoproite melts at a temperature higher than 1600 K. Eigenvalues of the thermal expansion tensor are calculated for the oxoborate and thermal expansion is described in comparison with its crystal structure.

Finite-Time Stability of a Second-Order Bang–Bang Sliding Control Type

This paper presents the double chain–integrator finite-time convergence in a closed loop with a second-order bang–bang sliding control. The direct Lyapunov method carried out the stability analysis and the reaching time estimation using a suitable non-smooth strong Lyapunov function. That is, the proposed energy function is strictly positive definite, with a strictly definite negative time derivative. Additionally, the proposed function estimates the reaching time in the presence of matching bounded perturbations. Numerical comparisons with well-known approaches were performed to assess the proposed strategy’s effectiveness.

‘On and Off’ intercalative binding behaviour of double chain surfactant cobalt(III) complex containing 2, 2′-bipyridyl ligand in β-Cyclodextrin: A detail approach on Host-guest inclusion of surfactant cobalt(III) complex and CT-DNA binding in micro-heterogeneous medium

The binding interaction of surfactant cobalt(III) complex, cis-[Co(bpy)2(HA)2](ClO4)3, in which bpy is 2,2-bipyridine and HA is hexadecylamine or cetylamnine with DNA was through intercalative mode via the long aliphatic chains present in the ligands. The binding was investigated by various techniques, electronic absorption, fluorescence spectroscopy, circular dichroism (CD), cyclic voltametry (CV) and viscosimetry measurements. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that the surfactant cobalt(III) complex binds to calf thymus DNA by intercalation through the aliphatic chain present in the complex into the base pairs of DNA. The presence of bipyridine ligand with larger π-frame work may also enhance intercalation. UV–vis., spectrum showed 4 nm bathochromic shift of the absorption band at 352 nm along with significant hypochromicity for the absorption band of the complex. The intrinsic binding constants(at below and above CMC are Kb = 2.41 × 105M−1, Kb = 3.12 × 106M−1 respectively) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the surfactant cobalt(III) complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. Competitive binding study with ethidium bromide (EB) shows that the surfactant complex exhibits the ability to displace the DNA-bound EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed. Besides the effect of binding of surfactant cobalt(III) complex to DNA in presence of β-cyclodextrin has also studied. This binding of the surfactant cobalt(III) complex in presence of β-cyclodextrin medium has been prevented (at below and above CMC are Kb = 5.45 × 104M−1, Kb = 6.92 × 105M−1 respectively) due to the incorporation of the aliphatic chains into the cavity of β-cyclodextrin. In presence of β-cyclodextrin the binding occur through surface and (or) groove binding can be attributed to the inclusion of the long aliphatic chain that is present in one of the ligands into cyclodextrin.

Double chain system for online and offline medical data sharing via private and consortium blockchain: A system design study.

With the informatization development and digital construction in the healthcare industry, electronic medical records and Internet medicine facilitate people's medical treatment. However, the current data storage method has the risk of data loss, leakage, and tampering, and can't support extensive and secure sharing of medical data. To realize effective and secure medical data storage and sharing among offline medical institutions and Internet medicine platforms, this study used a combined private blockchain and consortium blockchain to design a medical blockchain double-chain system (MBDS). This system can store encrypted medical data in distributed storage mode and systematically integrate the medical data of patients in offline medical institutions and Internet medicine platforms, to achieve equality, credibility, and data sharing among participating nodes. The MBDS system constructed in this study incorporated Internet medicine care services into the current healthcare system and provided new solutions and practical guidance for the future development of collaborative medical care. This study helped to solve the problems of medical data interconnection and resource sharing, improve the efficiency and effect of disease diagnosis, alleviate the contradiction between doctors and patients, and facilitate personal health management. This study has substantial theoretical and practical implications for the research and application of medical data storage and sharing.

Investigation of Four-Port Characteristic Dependence on Gate Length for MOSFETs in the Breakdown Region

In this article, gate length-dependent RF four-port characteristics of MOSFETs are investigated in the avalanche regime by using the double feedback and chain rule methods for the first time. The obvious decline of the imaginary part of source input impedance at high drain voltage for short-channel MOSFETs is investigated through the double feedback instead of only the series feedback for the origin of the inductive source impedance. The dominant terms causing the reduction of inductive source impedance due to parallel feedback are determined by this chain rule method. When compared with the conventional analysis due to short-channel effects on the direct-current (DC) characteristics of threshold voltage and substrate current, short-channel MOSFETs resulting in the aspect of RF characteristics are further analyzed by using different gate length MOSFETs. Besides, as gate length reduces, drain-to-source transmission raises significantly in the avalanche regime due to the RF avalanche network according to this analysis. This mechanism results in lower isolation at the breakdown for the shorter gate length MOSFETs. Good agreement of the four-port scattering parameter (S-parameter) between simulation and measurement is obtained for the MOSFETs operating in the both breakdown and saturation regions. The methods can be utilized for other advanced technology nodes and are helpful for the design of RF CMOS amplifiers in the impact ionization region.

Fault Diagnosis of Double Pitch Time-Sharing Meshing Toothed Conveyor Chain Transmission System Based on Neural Network

With the rapid development of industry, the production and demand of automobiles have increased significantly. The generation of cars often requires tens of thousands of processes, consisting of hundreds of assembly lines to complete. Chain conveyors are widely used in the transportation of automobile assembly lines. The existing conveyor chains are roller chains. With the improvement of the requirements for conveyor reliability, synchronization, and environmental friendliness, the characteristics of roller conveyor chains restrict the further development of chain conveyors. It is urgent to study a new conveyor chain system to improve the synchronization, reliability, and environmental friendliness of chain conveyors on hundreds of assembly lines. In this paper, the mathematical modeling, meshing analysis, reliability, and environmental friendliness of the parameters of the components of the double pitch time-sharing meshing toothed conveyor chain system are studied. In addition, a novel fault diagnosis method of double pitch time-sharing meshing toothed conveyor chain transmission system based on neural network model is proposed in this paper.

Enhanced Flotation Separation of Low-Rank Coal with a Mixed Collector: Experimental and Molecular Dynamics Simulation Study.

The efficient flotation separation of low-rank coal is still a difficult problem. The development of a collector is the key to solve the problem. In this study, a kind of mixed collector scheme with a practical value is proposed. The effects of the single collector dodecane (D) and methyl oleate (MO) and mixed collector D–didodecyl dimethyl ammonium bromide (DDAB) and MO–DDAB on flotation separation of low-rank coal were investigated. The flotation test results show that when the molar ratios of the mixed collector D–DDAB and MO–DDAB are 9:1 and the flotation time is 4 min, the cumulative combustible recovery of low-rank coal flotation is 71.49 and 76.73%, respectively, and the cleaned coal ash is 15.26 and 13.03%, respectively. The mixed collector significantly improves the flotation effect of low-rank coal compared with the single collector. According to the analysis results of the contact angle, wetting heat, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, the hydrophobicity of the low-rank coal surface is enhanced under the action of the mixed collector, and the adsorption between the mixed collector and coal surface is stronger. In addition, molecular dynamics (MD) simulation results show that compared with D or MO, DDAB tends to adsorb on the surface of low-rank coal, and the diffusion coefficients of water molecules on the surface of coal increase. The mixed collector first repels water molecules through its double hydrophobic carbon chain to weaken the binding of the coal surface to water molecules and then uses D or MO to further repel water molecules, thus effectively enhancing the surface hydrophobicity of low-rank coal.

Isopropyl 4-amino-benzoate.

The title compound, C10H13NO2, crystallizes with two mol-ecules (A and B) in the asymmetric unit. For A, the dihedral angle between the plane of the phenyl ring and the i-propyl substituent is 65.4 (3)° while for B this angle is 67.8 (3)°. In the crystal, the mol-ecules are linked by N-H⋯O and N-H⋯N hydrogen bonds to generate double chains propagating in the [100] direction.

FC-groups with Few Subnormal Non-normal Subgroups

A group G is said to be an FC-group if every conjugacy class of G has finite order and is said to be a T-group if every subnormal subgroup is normal in G. In this paper we give a characterization of groups that are both FC-groups and T-groups and go further in the study of FC-groups with few subnormal non-normal subgroups in the sense of the chain conditions. The structure of FC-groups satisfying the maximal, the minimal and the double chain condition on subnormal non-normal subgroups will be described.

Diverse structures and multi-step dielectric relaxation of three lead bromide hybrid crystals based on 1-aminopyridinium and its cyano-substituted Schiff bases

Oriented design of crystal structures to obtain specific properties is one of the hot topics in the field of chemistry and materials. In this paper, three organic–inorganic hybrid crystals were synthesized by the reaction of 1-aminopyridinium salts with o-, m-, and p-cyanobenzaldehyde and PbBr2. The asymmetric unit of 1 ([1- aminopyridinium][Pb2Br5], P21/m) contains half of the 1-aminopyridinium cation and the anion forms a zig-zag shaped puckered sheet of [Pb2Br5]∞; while 2 ([m-cyanobenzaldehyde-1-aminopyridinium][PbBr3], Pna21) includes a m-cyanobenzaldehyde-1-aminopyridinium Schiff base cation, and the anion forms a [PbBr3]∞ single chain. On the other hand, 3 ([p-cyanobenzaldehyde-1- aminopyridinium][PbBr3], P21/c) consists of a p-cyanobenzaldehyde-1- aminopyridinium Schiff base cation, with the anion forming a [Pb2Br6]∞ double chain. Structural analysis and energy framework calculations show that 2 possesses stronger π-π stacking and hydrogen bonding interactions, and its lattice energy and thermal stability are higher than those of 1 and 3. The combined use of CE and dielectric modulus analysis reveals a good correlation between multi-step dielectric relaxation and intermolecular forces. This strategy of modulating the crystal structure and dielectric properties by altering the position of the substituents provides useful assistance in the design of new relaxation dielectric materials.

Analysis of double-chain deoxyribonucleic acid dynamical system in pandemic confrontation

Every cell contains deoxyribonucleic acid (DNA), which serves as the fundamental information storage medium, preserving the genetic information required by organisms in order to survive and reproduce themselves. The analytical solution of the (3+1) double chain Deoxyribonucleic acid dynamical model is achieved using the Lie transformation approach. The equation is transformed into an ordinary differential equation (ODE) using three sequential symmetry reductions. Two examples are investigated, the results of which include some solitary wave solutions. The solutions found may be classified into three types: one-soliton, multi-soliton, and periodic wave solutions. Some of the answers that were discovered have been visually explored. The nonlinear dynamics of the system manifests itself in the solitary and anti-solitary waves of the DNA strands, which are both seen. The collected results may be beneficial to evaluate different applications for further scientific conclusions.