First principles study of electronic structure, chemical bonding and elastic properties of BiOCuS

The electronic structures, chemical bonding and elastic properties of the tetragonal phase BiOCuS were investigated by using density-functional theory （DFT） within generalized gradient approximation （GGA）. The calculated energy band structures show that the tetragonal phase BiOCuS is an indirect semiconductor with the calculated band gap of about 0.503 eV. The density of states （DOS） and the partial density of states （PDOS） calculations show that the DOS near the Fermi level is mainly from the Cu-3d state. Population analysis suggests that the chemical bonding in BiOCuS has predominantly ionic character with mixed covalent-ionic character. Basic physical properties, such as lattice constant, bulk modulus, shear modulus, elastic constants, were calculated. The elastic modulus and Poisson ratio were also predicted. The results show that tetragonal phase BiOCuS is mechanically stable and behaves in a ductile manner.

First principles calculation of electronic structure, chemical bonding and elastic properties of ultra-incompressible Re_2P

The electronic structures, chemical bonding and elastic properties of the Co2P-type structure phase ultra-incompressible Re2P （orthorhombic phase） were investigated by density-functional theory （DFT） within generalized gradient approximation （GGA）. The calculated energy band structures show that the orthorhombic structure phase Re2P is metallic material. The density of state （DOS） and the partial density of state （PDOS） calculations show that the DOS near the Fermi level is mainly from the Re-5d state. Population analysis suggests that the chemical bonding in Re2P has predominantly covalent character with mixed covalent-ionic character. Basic physical properties, such as lattice constant, bulk modulus, shear modulus, and elastic constants Cij, were calculated. The elastic modulus and Poisson ratio were also predicted. The results show that the Co2P-type structure phase Re2P is mechanically stable and behaves in a brittle manner.

First principles calculation on electronic structure,chemical bonding,elastic and optical properties of novel tungsten triboride

The electronic structures,chemical bonding,elastic and optical properties of the novel hP24 phase WB3 were investigated by using density-functional theory(DFT) within generalized gradient approximation(GGA).The calculated energy band structures show that the hP24 phase WB3 is metallic material.The density of state(DOS) and the partial density of state(PDOS) calculations show that the DOS near the Fermi level is mainly from the W 5d and B 2p states.Population analysis suggests that the chemical bonding in hP24-WB3 has predominantly covalent characteristics with mixed covalent-ionic characteristics.Basic physical properties,such as lattice constant,bulk modulus,shear modulus and elastic constants Cij were calculated.The elastic modulus E and Poisson ratio υ were also predicted.The results show that hP24-WB3 phase is mechanically stable and behaves in a brittle manner.Detailed analysis of all optical functions reveals that WB3 is a better dielectric material,and reflectivity spectra show that WB3 can be promised as good coating material in the energy regions of 8.5-11.4 eV and 14.5-15.5 eV.

The Chemical Principle of Green Coal Power

Coal is still a major source of energy, also a major source of SO_2, NOx and CO_2 emission though. Removal of SO_2 and NOx doubled the cost of power generation, and capture of CO_2 is equivalent to double the market price of power coal. The GCP （green coal power） is the power generated in coal-combustion with zero emission. The author indicates that it is possible to make coal-fired power plants emission free based on thermodynamic analysis and purposely designed experiments using SFG （simulated flue gases）. It is concluded in the study that all SO_2 and NOx in the post-combustion flue gas are reduced to inoffensive substances at temperature lower than 750 ℃ when contacting carbon and elemental sulfur is separated in succeeded cooling of flue gas at temperatures 200-400 ℃, and the ultrafine dusts are trapped in condensed water at temperature blow 100 ℃. Based on chemical engineering expertise the author is sure that the cost for removing acid gases is much lower than any clean coal technologies known to today. Instead of capture, the remained CO_2 is converted to CO in the second time contact with carbon at 900-950 ℃. CO is the raw material of chemical synthesis and, thus, CO_2 is stored in chemical products such as methanol, fertilizer, plastics, etc. The simple and low-cost processing allows GCP utilized in practice easily.

First principles calculation on ternary stannide phase narrow band gap semiconductor Na_2MgSn

The electronic structures,chemical bonding,elastic and optical properties of the ternary stannide phase Na2MgSn were investigated by using density-fimctional theory（DFT） within generalized gradient approximation（GGA）.The calculated energy band structures show that Na2MgSn is an indirect semiconductor material with a narrow band gap 0.126 eV.The density of state（DOS）and the partial density of state（PDOS） calculations show that the DOS near the Fermi level is mainly from the Na 2p,Mg 3p and Sn5 p states.Population analysis suggests that there are strongly bonded Mg-Sn honeycomb layers in Na2MgSn.Basic physical properties,such as lattice constant,bulk modulus,shear modulus,elastic constants c（ij） were calculated.The elastic modulus E and Poisson ratio v were also predicted.The results show that Na2MgSn is mechanically stable soft material and behaves in a brittle manner.Detailed analysis of all optical functions reveals that Na2MgSn is a better dielectric material,and reflectivity spectra show that Na2MgSn promise as good coating materials in the energy regions 6.24-10.49 eV.

First-principles Study on the Electronic Structure of Novel Titanium Yttrium Mixed-metal Nitride Clusterfullerene

We present a first-principles study on the geometric, vibrational and electronic properties of a novel Y-based non-scandium mixed-metal nitride clusterfullerene （TiY2N@C80）. Theoretical results indicate that the fundamental electronic properties of TiY2N@C80 are similar to that of TiSc2N@C80, but dramatically different from that of ScaN@C800 and YaN@C80 molecules. We find that the magnetism of TiY2N@C80 is quenched by carrier doping. The rotation energy barrier of the TiY2N cluster in C80 cage was obviously increased by exohedral chemical modification with pyrrolidine monoadduct.

First Principles Calculation of Magnetic Resonance Properties of Cu_2-<i>δ</i>X (X = Se, S, Te)

In order to have a better understanding of the electronic structures and physical properties of Cu2-δX (X = Se, S, Te) copper chalcogenides. First principles were performed to calculate the chemical shift, band structure, and electron density of states of Cu2-δX (X = Se, S, Te). By comparing our calculation results with previous experimental works, we found that the predicted electronic structures of Cu2Se, Cu2Te and Cu2S transform from semimetal to semiconductor after adding on-site Coulomb U, which reflects the real properties of the materials. By using (Density Functional Theory) DFT + U method, the calculation result is close to the real electronic structure. The calculation result of chemical shift of adding U does not reach the ideal expectation, and the reason is not clear at present. In this paper, the theoretical electronic structures of Cu2Se, Cu2Te and Cu2S are better calculated by DFT + U method and compared with the actual properties. The effect of Cu-s electron on the chemical shift is understood, and a theoretical result of the chemical shift is calculated, which provides a powerful reference for the subsequent research and understanding of the electronic structure and physical properties of the compounds with S groups of Cu.

化工原理课程教学方法改进与优化措施探讨

化工原理课程是化工相关专业的核心课程,由于化工原理讲授的是复杂的工程理论基础,在教学过程中存在课程难度大、理论与实践脱轨、学生学习动力不足等问题。本文针对这些问题结合多样化教学、生活/工程实际和多维度评价等手段,探讨化工原理课程教学改进与优化的方法,培养学生学习积极性,提高教学效果。

O2O混合教学在食品工程专业“化工原理”课程的应用探索

结合“化工原理”课程特点,构建一个基于学堂在线为云平台的O2O精准教学实施策略。将网络教学与课堂教学相结合,改变传统课堂教学的结构,重构课堂教学的过程和学生评价方式。O2O混合教学具有学习资源丰富性和交流上的即时性和方便性,更好地促进学生自主学习课程的积极性,提高课程的教学效果。

C-H-F氛围下金刚石薄膜的低温CVD生长过程分析

基于第一性原理的密度泛函理论对C-H-F氛围下低温CVD金刚石薄膜的生长过程进行仿真分析,计算H、F原子在氢终止金刚石表面发生萃取反应的吸附能、反应热与反应能垒,并分析CF_(3)、CF_(2)、CF 3种生长基团在带有活性位点基底上的吸附。结果表明:与H原子相比,F原子更容易在氢终止金刚石表面萃出H,并以HF形式脱附,且在C-H-F氛围下有利于在低温时产生更多的活性位点;CF_(3)、CF_(2)、CF基团在吸附后的结构和吸附能绝对值都更有利于金刚石相的生成,适当提高CF_(3)、CF_(2)、CF基团的浓度有助于实现金刚石相的更高速率生长。

工程教育认证背景下基于BOPPPS模型的化工原理课程教学设计

在工程教育认证的大背景下,化工及相关专业对化工原理课程进行教学改革显得尤为重要。本文以现阶段化工原理课程教学中存在的问题为切入点,以“静力学方程及应用”的教学设计为实例,探讨了BOPPPS教学模式在化工原理课堂教学设计中的应用效果。研究结果证实,BOPPPS教学模式能够显著提升学生的课堂参与度,有效激发学生的主观能动性,从而显著增强化工原理课堂的教学效果。

工程教育视角下化工原理实验课程建设的思考

根据化工原理实验课程综合性、设计性和实践性强的特点,提出层次化实验教学方式,不断培养学生学习兴趣,提高创新思维和能力水平。同时,结合教学经验,在课程预习及实验操作等方面对实验课程的教学过程和考核方式进行改进,充分调动了学生实验学习的积极性,使学生掌握实验技能,有助于培养学生的工程意识、实践能力,不断提升教学效果,全面提高化工原理实验课程教学质量。

成果导向教育背景下化工原理教学改革与实践

化工原理是化工类及相关专业的核心专业基础课,对于夯实化工创新人才的专业基础知识,培养学生工程能力和激发科技强国意识至关重要。然而,该课程长期以来的教育理念和教学方法滞后于行业发展变化和社会对高素质工程技术人才的需求。为此,该课程改革紧扣专业人才培养方案,以成果导向教育理念进行教学设计,构建基于“雨课堂+BOPPPS”的有效教学模型。通过重组教学内容、构建思维导图,拓展教学资源和教学平台,改革课程评价机制,全方位融入课程思政,教学效果得到极大提升,实现从教学到教育的转变路径。

课程思政背景下化工原理教学的思考与实践

化工原理课程是高校化工及其相关专业开设的一门专业基础课程。本文在课程思政背景下,将思政元素融入到化工原理课程的教学中,在爱国敬业、理想信念、使命感的培养,强化环保、健康和安全理念及法律规范等意识的培养,在践行绿色发展观,科学方法论等哲学思维的运用等几方面入手,将课程内容与课程思政元素有机结合,不仅使学生对课程内容能够理解通透,而且对树立科学的人生观、价值观起到积极作用。

化工原理课程教学中课程思政的探索

化工类专业是中国高等院校培养化工类专业应用型人才的主渠道,同时也是推进中国新质生产力发展的重要内容。当前,化工原理课程作为中国高等院校化工类专业的专业必修课,不仅是教师们培养应用性技术人才、实现立德树人根本目标的主阵地,更是培养新时代中国特色社会主义事业的建设者和接班人的主阵地,必须做好“思政课程”到“课程思政”的重要转变,必须做好专业课“课程思政”的历史性转变。

化工原理实验与前沿科研成果相融合的探索

基于化工原理实验教学实践经验,将前沿科研成果融入其中,设定专业特色实验、探究研讨实验、设计原创实验,以期形成丰富的实验资源、特色课程和教材及支撑创新人才的培养。在学生接触到科研实验的同时,能够深化所学的化工原理理论知识,开拓前沿科研学术视野,激励其自主学习,产生浓厚的科研兴趣,提高创新能力。

头发曲折变形记

烫发是人类追求美好的一种方式,也是现代流行的一种美发技术。本文通过虚拟参观美发展览介绍了烫发简史,头发的化学组成,以及化学烫发的原理,旨在展示化学对人类的重要性,帮助人们辩证理解烫发的利弊,并以正确的态度对待烫发。

恒压过滤实验中测定值偏离理论值的原因探讨

恒压过滤实验是化工原理实验的重要组成部分,很长时间以来,河北科技大学学生在化工原理恒压过滤实验中测得的洗涤速率和最终过滤速率的比值,与理论值相差悬殊。通过对该实验过程的观察和数据处理结果的分析,指出了三个产生此问题的可能原因,并通过实验进行了验证,最终确定了主要的原因为搅拌速度、螺杆压紧程度和过滤终点,最后提出了该实验操作过程中的注意事项和实验设备改进方案。

一流课程建设背景下化工原理教学改革与实践

化工原理是面向化学工程与工艺等专业开设的专业基础课。在一流课程建设背景下,化工原理课程建设有了新的要求。针对传统教学中存在的问题,课程通过线上资源建设、重构教学内容、融入课程思政、线上线下混合式教学模式、改革评价体系等举措,激发了学生学习化工原理的兴趣,提升了学生工程实践能力和创新能力,为培养高素质应用型工程人才奠定基础。

工程教育认证背景下“化工原理实验”课程体系优化的思考与探索

工程教育认证是衡量高校工程教育质量的重要标准,也对“化工原理实验”课程体系提出了新的要求和更大的挑战。为促进“化工原理实验”课程教学质量的提升、推动工程教育认证工作的开展,探讨在工程教育认证背景下“化工原理实验”课程的实验内容、教学方法、课程设置和评价机制等方面的优化策略与建议。多项优化策略在某高等院校化学工程与工艺专业实施后,实现了课程体系的不断优化,建立起了完善的实验教学管理机制和质量控制体系,从学生成绩和大赛表现来看取得了良好的成效。