Chemical reaction

化学反应
  • 文章类型: Journal Article
    在喷射器喷射期间产生的气穴可以显著影响燃料雾化。激光诱导空化气泡是激光诱导等离子体点火技术中的重要现象。受限于实验测量的困难,数值模拟已成为研究激光空化气泡的重要工具,但是以前用于研究激光诱导空化气泡动力学的大多数数值模型通常都忽略了化学反应的影响。在这项研究中,有限体积法用于通过考虑空化气泡内的传热和传质以及化学反应来求解可压缩的二维雷诺平均Navier-Stokes方程。评估了整体反应和基本反应对空化气泡的影响,分别。发现通过另外考虑数值模型内的化学反应,较低的最大温度和较高的最大压力预测气泡内。并且由化学反应产生的不凝气体增强了空化气泡的后续膨胀过程。此外,将单侧壁边界条件对空化气泡的影响与无限边界条件进行了比较。受墙壁边界的影响,空化气泡在破裂过程中在气泡远离壁的一侧形成局部高压,这导致气泡被压缩成“新月”形状。由于壁引起的局部损失,气泡内部的最大压力和温度较低。
    Cavitation generated during injector jetting can significantly affect fuel atomization. Laser-induced cavitation bubble is an important phenomenon in laser induced plasma ignition technology. Limited by the difficulties in experimental measurements, numerical simulations have become an important tool in the study of laser-induced cavitation bubble, but most previous numerical models used to study the dynamics of laser-induced cavitation bubble usually ignore the effect of chemical reactions. In this study, the finite volume method is used to solve the compressible two-dimensional reynolds averaged Navier-Stokes equation by considering the heat and mass transfer as well as the chemical reactions within the cavitation bubble. The effects of overall reaction and elementary reactions on the cavitation bubble are evaluated, respectively. It is found that by additionally considering chemical reactions within the numerical model, lower maximum temperatures and higher maximum pressures are predicted within the bubble. And the generated non-condensable gases produced by the chemical reactions enhance the subsequent expansion process of the cavitation bubble. Besides, the effect of the one-sided wall boundary condition on cavitation bubble is compared with the infinite boundary condition. Influenced by the wall boundary, the cavitation bubble forms a localized high pressure on the side of the bubble away from the wall during the collapse process, which causes the bubble to be compressed into a \"crescent\" shape. The maximum pressure and temperature inside the bubble are lower due to localized losses caused by the wall.
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  • 文章类型: Journal Article
    本研究旨在评估化学气化和HEPES作为体外成熟过程中pH控制的替代系统对牛卵母细胞能力的影响。将20种牛卵丘卵母细胞复合物(COCs)随机分配并在以下实验组之一中培养24h:(i)化学反应(ChRG)系统:碳酸氢钠和柠檬酸反应产生的CO2(ii)培养基TCM-HEPES(HEPES-G);(iii)常规培养箱中的对照组(CNTG)。体外成熟(IVM)后,COCs进行了体外受精(IVF),并在常规培养箱中进行体外培养(IVC)。我们评估了卵母细胞的核成熟,卵裂和胚泡率,除了BAX的相对mRNA表达,卵母细胞和卵丘细胞中的BMP-15、AREG和EREG基因。CNTG和ChRG中中期II的卵母细胞比例(77.57%和77.06%)高于HEPES-G(65.32%;p=.0408和.0492)。CNTG和ChRG之间的胚泡产生相似(26.20%和28.47%;p=.4232),而HEPES-G(18.71%)更低(p=.001)。与CNTG相比,HEPES-G中卵丘细胞中BAX基因的相对mRNA表达明显更高(p=0.0190)。此外,与CNTG相比,HEPES-G卵母细胞中BMP-15基因的相对mRNA表达较低(p=0.03)。总之,不充分的气氛控制对卵母细胞成熟有不利影响。然而,使用化学气化可以有效替代牛COCs培养。
    This study aimed to evaluate the effect of chemical gasification and HEPES as alternative systems to pH control during in vitro maturation on bovine oocytes competence. Groups of 20 bovine cumulus oocytes complexes (COCs) were randomly distributed and cultured for 24 h in one of the following experimental groups: (i) chemical reaction (ChRG) system: CO2 generated from sodium bicarbonate and citric acid reaction (ii) culture media TCM-HEPES (HEPES-G); and (iii) control group (CNTG) in conventional incubator. After in vitro maturation (IVM), the COCs were in vitro fertilized (IVF), and in vitro cultivated (IVC) in a conventional incubator. We evaluated oocyte nuclear maturation, cleavage and blastocyst rates, in addition to the relative mRNA expression of BAX, BMP-15, AREG and EREG genes in oocytes and cumulus cells. The proportion of oocytes in metaphase II was higher in CNTG and ChRG (77.57% and 77.06%) than in the HEPES-G (65.32%; p = .0408 and .0492, respectively). The blastocyst production was similar between CNTG and ChRG (26.20% and 28.47%; p = .4232) and lower (p = .001) in the HEPES-G (18.71%). The relative mRNA expression of BAX gene in cumulus cells was significantly higher (p = .0190) in the HEPES-G compared to the CNTG. Additionally, the relative mRNA expression of BMP-15 gene was lower (p = .03) in oocytes from HEPES-G compared to the CNTG. In conclusion, inadequate atmosphere control has a detrimental effect on oocyte maturation. Yet, the use of chemical gasification can be an efficient alternative to bovine COCs cultivation.
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  • 文章类型: Journal Article
    化学反应和它的反应环境是有内在联系的,特别是在狭窄的细胞空间内。传统的化学反应模型通常使用以浓度为主要变量的微分方程,忽略了溶液中的密度异质性以及反应与其环境之间的相互作用。我们模拟了在几何空间内化学反应与其环境之间的相互作用,比如在牢房里,通过分子簇的大小来代表环境。在没有波动的情况下,团簇大小变化与分子的激活和失活之间的相互作用会引起振荡。然而,在不稳定的环境中,系统达到波动稳定状态。当一种酶被引入这种稳定状态时,类似于动作电位尖峰序列的振荡出现。我们检查了这些尖峰序列的行为,并证明了它们可用于实现逻辑门。我们讨论了化学反应与其环境之间相互作用产生的振荡和计算,探索他们为化学智能做出贡献的潜力。
    A chemical reaction and its reaction environment are intrinsically linked, especially within the confines of narrow cellular spaces. Traditional models of chemical reactions often use differential equations with concentration as the primary variable, neglecting the density heterogeneity in the solution and the interaction between the reaction and its environment. We model the interaction between a chemical reaction and its environment within a geometrically confined space, such as inside a cell, by representing the environment through the size of molecular clusters. In the absence of fluctuations, the interplay between cluster size changes and the activation and inactivation of molecules induces oscillations. However, in unstable environments, the system reaches a fluctuating steady state. When an enzyme is introduced to this steady state, oscillations akin to action potential spike trains emerge. We examine the behavior of these spike trains and demonstrate that they can be used to implement logic gates. We discuss the oscillations and computations that arise from the interaction between a chemical reaction and its environment, exploring their potential for contributing to chemical intelligence.
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  • 文章类型: Journal Article
    在这篇文章中,已经研究了在Cattaneo-Christov热通量模型上发生化学反应的上对流麦克斯韦流体在指数拉伸薄板上的传热流动的数值解。使用相似性转换,将非线性偏微分方程控制系统转化为常微分方程组。在MATLAB软件的帮助下,通过连续线性化方法对所得转换的方程进行了数值求解。创建了图形表示以分析相关流特性的物理见解。这些发现以速度的形式呈现,温度,和浓度分布。随着弛豫时间参数的变化,当地的努塞尔人数增加了。热弛豫时间与流体温度成反比。此外,随着反应速率参数水平的增加,浓度边界层变得更薄。该模型的结果可适用于生物流体和工业情况。分析的结果与以前的研究结果之间存在极好的一致性。
    In this article, the numerical solutions for the heat transfer flow of an upper-convected Maxwell fluid across an exponentially stretched sheet with a chemical reaction on the Cattaneo-Christov heat flux model have been investigated. Using similarity transformation, the controlling system of nonlinear partial differential equations was transformed into a system of ordinary differential equations. The resulting converted equations were solved numerically by a successive linearization method with the help of MATLAB software. A graphic representation was created to analyze the physical insights of the relevant flow characteristics. The findings were presented in the form of velocity, temperature, and concentration profiles. As the relaxation time parameter varied, the local Nusselt number increased. The thermal relaxation time was shown to have an inverse relationship with fluid temperature. Furthermore, the concentration boundary layer becomes thinner as the levels of the reaction rate parameter increase. The results of this model can be applicable in biological fluids and industrial situations. Excellent agreement exists between the analysis\'s findings and those of the previous studies.
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  • 文章类型: Journal Article
    蓝色钙钛矿发光二极管(PeLED)是实现基于钙钛矿材料的全彩显示和照明的重要途径。然而,相对较低的外部量子效率(EQE)阻碍了它们向商业应用的发展。准二维(准2D)钙钛矿是蓝色PeLED的有希望的候选者,对低维相的优化控制有助于增强激子的辐射特性。在这里,有机分子掺杂剂对准2D钙钛矿薄膜中各种n相结构结晶的影响。结果表明,高反应性双(4-(三氟甲基)苯基)氧化膦(BTF-PPO)分子可以通过化学反应有效抑制有机间隔阳离子有序层状钙钛矿相的形成,同时钝化那些不协调的Pb2+缺陷。因此,制备的PeLED表现出16.6%的最大EQE(@490nm)。该发现为设计准2DPeLED中的相位调制掺杂剂分子提供了新的途径。
    Blue perovskite light-emitting diodes (PeLEDs) are crucial avenues for achieving full-color displays and lighting based on perovskite materials. However, the relatively low external quantum efficiency (EQE) has hindered their progression towards commercial applications. Quasi-two-dimensional (quasi-2D) perovskites stand out as promising candidates for blue PeLEDs, with optimized control over low-dimensional phases contributing to enhanced radiative properties of excitons. Herein, the impact of organic molecular dopants on the crystallization of various n-phase structures in quasi-2D perovskite films. The results reveal that the highly reactive bis(4-(trifluoromethyl)phenyl)phosphine oxide (BTF-PPO) molecule could effectively restrain the formation of organic spacer cation-ordered layered perovskite phases through chemical reactions, simultaneously passivate those uncoordinated Pb2+ defects. Consequently, the prepared PeLEDs exhibited a maximum EQE of 16.6% (@ 490 nm). The finding provides a new route to design dopant molecules for phase modulation in quasi-2D PeLEDs.
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  • 文章类型: Journal Article
    查尔酮是一种简单的天然存在的α,具有生物学重要性的β-不饱和酮,这也可以很容易地合成在实验室通过两个芳香支架之间的反应。在植物中,查耳酮是作为不同骨架的多酚化合物而出现的,它们是传统医学实践多年的生物活性分子。已经开发了基于查尔酮的铅分子,具有不同的潜力,如抗菌,抗病毒,抗炎,抗癌,抗氧化剂,抗糖尿病药,抗高尿酸血症,和抗溃疡作用。Chalcones贡献了相当多的片段,以提供具有靶向各种疾病的治疗用途的重要杂环分子。这些特征使查尔酮成为研究人员感兴趣的话题,并吸引了对这种广泛适用结构的研究。这篇综述强调了对合成进行的广泛探索,生物转化,化学反应,杂交,和查尔酮的药理潜力,并旨在提供广泛的,彻底,并对其重要性进行批判性审查,强调它们的属性,化学,和生物医学应用,以促进对药物化学中这种潜在支架的未来研究。
    Chalcone is a simple naturally occurring α,β-unsaturated ketone with biological importance, which can also be easily synthesized in laboratories by reaction between two aromatic scaffolds. In plants, chalcones occur as polyphenolic compounds of different frameworks which are bioactive molecules that have been in traditional medicinal practice for many years. Chalcone-based lead molecules have been developed, possessing varied potentials such as antimicrobial, antiviral, anti-inflammatory, anticancer, anti-oxidant, antidiabetic, antihyperurecemic, and anti-ulcer effects. Chalcones contribute considerable fragments to give important heterocyclic molecules with therapeutic utilities targeting various diseases. These characteristic features have made chalcone a topic of interest among researchers and have attracted investigations into this widely applicable structure. This review highlights the extensive exploration carried out on the synthesis, biotransformations, chemical reactions, hybridization, and pharmacological potentials of chalcones, and aims to provide an extensive, thorough, and critical review of their importance, with emphasis on their properties, chemistry, and biomedical applications to boost future investigations into this potential scaffold in medicinal chemistry.
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  • 文章类型: Journal Article
    超分子结构广泛存在于生命系统中,通常由复杂的代谢过程时空调节,以实现重要的生物学功能。受到生命系统的启发,通过将化学反应与分子自组装过程耦合,在合成场景中实现对超分子材料自组装的时空控制已经做出了巨大的努力。在这次审查中,我们重点研究了利用化学反应在空间和时间上进行调节的超分子水凝胶的相关工作。首先,我们总结了超分子水凝胶的空间控制自组装是如何通过化学反应指示的自组装来实现的,并讨论了这种自组装方法学在生物治疗中的应用。第二,我们回顾了由化学反应网络决定的动态超分子水凝胶,该网络可以随时间演变其结构和性质。第三,我们讨论了通过反应-扩散耦合自组装方法在空间和时间上控制超分子水凝胶自组装的最新进展。最后,我们为未来利用化学反应进一步发展时空控制的超分子水凝胶提供了一个视角。
    Supramolecular structures are widespread in living system, which are usually spatiotemporally regulated by sophisticated metabolic processes to enable vital biological functions. Inspired by living system, tremendous efforts have been made to realize spatiotemporal control over the self-assembly of supramolecular materials in synthetic scenario by coupling chemical reaction with molecular self-assembly process. In this review, we focused on the works related to supramolecular hydrogels that are regulated in space and time using chemical reaction. Firstly, we summarized how spatially controlled self-assembly of supramolecular hydrogels can be achieved via chemical reaction-instructed self-assembly, and the application of such a self-assembly methodology in biotherapy was discussed as well. Second, we reviewed dynamic supramolecular hydrogels dictated by chemical reaction networks that can evolve their structures and properties against time. Third, we discussed the recent progresses in the control of the self-assembly of supramolecular hydrogels in both space and time though a reaction-diffusion-coupled self-assembly approach. Finally, we provided a perspective on the further development of spatiotemporally controlled supramolecular hydrogels using chemical reaction in the future.
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  • 文章类型: Journal Article
    这项研究反映了Oldroyd-B流体在可渗透表面上的流动受到融化的影响的检查,滑移效应,倾斜磁场和化学反应。使用内置的MATLAB工具bvp4c解析控制方程,动量的算术计算,热和浓度方程执行。结果以图形方式显示。数值结果通过速度图形描绘,浓度,几个模型变量的温度曲线。所取得的结果与公开文献中先前建立的发现具有良好的一致性。获得的结果表明,Deborah数β1减小了动量边界层厚度,而Deborah数β2增强了相邻的动量边界层。此外,熔化参数Me的温度曲线下降。这项研究的应用超越了各种工程学科,在聚合物加工中提供实用的解决方案和优化机会,涂层技术,冷却系统,材料加工,生物医学和环境工程。
    This investigation reflects an examination of Oldroyd-B fluid flow over a permeable surface subjected to the effects of melting, slip effect, inclined magnetic field and chemical reactions. The governing equations are resolved using the bvp4c inbuilt MATLAB tool, the arithmetic computation for the momentum, thermal and concentration equations are executed. The results are exhibited graphically. Numerical outcomes are graphically depicted by aid of velocity, concentration, temperature profiles for several model variables. The achieved results exhibit a promising agreement with the previously established findings available in the open literature. The results obtained indicated that Deborah number β 1 reduces the momentum boundary layer thickness whereas Deborah number β 2 enhances the adjacent momentum boundary layer. Furthermore, temperature profile declined for melting parameter Me . The application of this study transcends various engineering disciplines, offering practical solutions and optimization opportunities in polymer processing, coating technologies, cooling systems, materials processing, biomedical and environmental engineering.
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  • 文章类型: Journal Article
    结构的重构对于实现工程材料的新拓扑和新功能具有重要意义。已经报道了现有的可重构策略,包括基于热量的方法,机械不稳定性,肿胀,折纸/kirigami设计,和电磁驱动。然而,这些方法主要涉及宿主材料和相关刺激之间的物理相互作用。在这里,一本小说,易于操纵,通过在水凝胶反应性微环境中使用主体材料的化学反应,提出了聚合物结构的可控重新配置策略。3D打印聚己内酯(PCL)晶格在聚丙烯酰胺(PAAm)水凝胶前体水溶液中转化,其中紫外线(UV)引发PCL和AAm之间的非均相接枝聚合。原位显微镜表明,PCL梁经历体积膨胀和合作屈曲,导致PCL晶格转换为正弦图案。通过调整PCL光束直径,可以轻松调整和图案化转换过程,单元格宽度,和UV光开关状态。通过使用UV掩模实现控制畴形成。该框架使设计,fabrication,和架构材料的编程,并激发了新颖的4D打印方法的开发。
    Reconfiguration of architected structures has great significance for achieving new topologies and functions of engineering materials. Existing reconfigurable strategies have been reported, including approaches based on heat, mechanical instability, swelling, origami/kirigami designs, and electromagnetic actuation. However, these approaches mainly involve physical interactions between the host materials and the relevant stimuli. Herein, a novel, easy-manipulated, and controllable reconfiguration strategy for polymer architectures is proposed by using a chemical reaction of host material within a hydrogel reactive microenvironment. 3D printed polycaprolactone (PCL) lattices transformed in an aqueous polyacrylamide (PAAm) hydrogel precursor solution, in which ultraviolet (UV) light triggered heterogeneous grafting polymerization between PCL and AAm. In situ microscopy shows that PCL beams go through volumetric expansion and cooperative buckling, resulting in transformation of PCL lattices into sinusoidal patterns. The transformation process can be tuned easily and patterned through the adjustment of the PCL beam diameter, unit cell width, and UV light on-off state. Controlling domain formation is achieved by using UV masks. This framework enables the design, fabrication, and programming of architected materials and inspires the development of novel 4D printing approaches.
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  • 文章类型: Journal Article
    进行了有限差分数值模拟审查,以评估产热的综合影响,浮力,通过考虑斜坡表面浓度和温度,沿着指数加速的可渗透垂直板流动的非稳态水磁混合对流化学反应和辐射卡森流体中的粘性耗散和焦耳加热在多孔介质中。通过采用胜任的隐式Crank-Nicolson有限差分程序,对描述流动模型的无量纲非线性耦合PDE进行了数值处理。速度的方差,温度,由于流动约束参数的不同,浓度分布通过图形表示暴露出来。皮肤摩擦的计算结果,努塞尔和舍伍德数字以表格形式描绘。研究的最终结果揭示了热辐射的影响,粘性耗散,和产热参数扩大了温度和速度分布。流体运动随着Casson参数和磁场强度的增长而收缩。上升的化学反应参数抑制了浓度和速度分布。非常重要的是,流体动量是有区别的,温度,在等温板温度的情况下,浓度比斜坡壁温度更快。这种研究可能会发现特定的工业和医疗用途,例如玻璃制造,原油净化,润滑,造纸,心血管设计中的血液运输研究,等。
    A finite difference numerical simulation scrutiny is executed to evaluate the combined impacts of heat generation, buoyancy forces, viscous dissipation and Joule heating in unsteady hydro-magnetic mixed convective chemically reactive and radiative Casson fluid flowing along an exponentially accelerating permeable vertical plate engrossed in a porous media by considering ramp surface concentration and temperature. The dimensionless non-linear coupled PDEs describing the flow model are dealt numerically by adopting the competent implicit Crank-Nicolson finite difference procedure. The variance of velocity, temperature, and concentration distributions are exposed via graphical representations due to the dissimilarity of the flow restrained parameters. Computational outcomes of the skin-friction, Nusselt and the Sherwood numbers are portrayed in the tabular pattern. The final outcomes of the research exposed that the impacts of thermal radiation, viscous dissipation, and heat production parameters enlarges the temperature and velocity distributions. The fluid motion deflates for growing Casson parameter and magnetic field intensity. The rising chemical reaction parameter suppresses the concentration and velocity distributions. Very importantly it is distinguished that fluid momentum, temperature, and concentration are quicker in the instance of isothermal plate temperature than ramp wall temperature. This kind of research may find specific industrial and medical utilizations such as glass manufacturing, crude oil purification, lubrication, paper production, blood transport study in cardiovascular design, etc.
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