摘要：采用原位合成的方法设计并制备了SiC-BN复合陶瓷.通过热力学计算,选择了制备SiC-BN复合陶瓷的反应方程式,并通过进一步的计算,选择合适的烧结工艺保证了反应方程式Si3N4+B4C+2C=3SiC+4BN不会受到副反应的影响.通过实验验证此反应在1700℃能够反应完成,生成β-SiC和h-BN.

摘要：Vray课程是环境艺术设计专业、园林景观专业、建筑规划专业、室内设计等专业所运用的一门计算机辅助课程。可以说是连接基础理论、专业设计的桥梁。同时,也是反应效果表现和设计水平的专业技术课程。当前,Vray是室内设计当中最常使用的一种效果图渲染工具,而且功能是非常强大的。本文以Vray在室内设计中教学思路作为导入点,并且以Vray渲染课程项目案例教学法为例,探讨Vray渲染技术在室内设计教学中的运用。

摘要：计算机辅助软件具有多方面的优势,应用于园林工程设计可以有效提升设计的效果,设计效果的表达更加直接快捷。在园林工程设计中,要注重发挥计算机辅助软件的作用,结合园林工程设计解决好存在的制约问题。

摘要：The thermal expansion coefficient(TEC)and thermal conductivity(k)of thermal fillers are key factors for designing thermal management and thermal protection composite *** to its unique advantages,hexagonal boron nitride(h-BN)is one of the most commonly used thermal ***,its TEC and k values are still unclear due to the inconsistency of characterization techniques and sample *** this work,these disputes were addressed using the quasi-harmonic approximation(QHA)method and phonon Boltzmann transport equation(BTE)theory based on the density functional theory(DFT),*** accuracy of our calculated TEC and k values was confirmed by previously reported experimental results,and the underlying physical principles were analyzed from the phonon *** TEC results show that the h-BN has small in-plane negative value and large cross-plane positive value,which are-2.4×10^(-6) and 36.4×10^(-6) K^(-1) at 300 K,*** the anisotropic TEC is mainly determined by the anisotropic isothermal bulk modulus and the low-frequency out-of-plane longitudinal phonon *** found that the convergence of cutoff radius and q-grid size have significant effect on the accuracy of k of *** results show that the in-plane k is much higher than the cross-plane k,and the values at 300 K are 286.6 and 2.7 W m^(-1) K^(-1),*** anisotropic phonon group velocity arising from the vibration behaviors of acoustic phonon modes should be primarily responsible for the anisotropic *** calculated TEC and k values will provide important references for the design of h-BN composite materials.

摘要：Hexagonal boron nitride(h-BN)ceramics have become exceptional materials for heat-resistant components in hypersonic vehicles,owing to their superior thermal stability and excellent dielectric ***,their densification during sintering still poses challenges for researchers,and their mechanical properties are rather *** this study,SrAl_(2)Si_(2)O_(8)(SAS),with low melting point and high strength,was introduced into the h-BN ceramics to facilitate the sintering and reinforce the strength and ***,BN-SAS ceramic composites were fabricated via hot press sintering using h-BN,SrCO_(3),Al_(2)O_(3),and SiO_(2) as raw materials,and effects of sintering pressure on their microstructure,mechanical property,and thermal property were *** thermal shock resistance of BN-SAS ceramic composites was *** show that phases of as-preparedBN-SAS ceramic composites are h-BN and h-SrAl_(2)Si_(2)O_(8).With the increase of sintering pressure,the composites’densities increase,and the mechanical properties shew a rising trend followed by a slight *** a sintering pressure of 20 MPa,their bending strength and fracture toughness are(138±4)MPa and(1.84±0.05)MPa·m^(1/2),*** sintered at 10 MPa exhibit a low coefficient of thermal expansion,with an average of 2.96×10^(-6) K^(-1) in the temperature range from 200 to 1200℃.The BN-SAS ceramic composites prepared at 20 MPa display higher thermal conductivity from 12.42 to 28.42 W·m^(-1)·K^(-1) within the temperature range from room temperature to 1000℃.Notably,BN-SAS composites exhibit remarkable thermal shock resistance,with residual bending strength peaking and subsequently declining sharply under a thermal shock temperature difference ranging from 600 to 1400℃.The maximum residual bending strength is recorded at a temperature difference of 800℃,with a residual strength retention rate of 101%.As the thermal shock temperature difference increase,the degree of oxida

摘要：为优选落羽杉大龄母树插穗的扦插繁殖技术,以期培育大量的落羽杉良种壮苗满足三峡消落带植被修复的需要,采用正交试验设计,探究不同外源激素、浓度以及处理时间对三峡消落带落羽杉大龄母树插穗扦插生根的影响,运用隶属函数法对各处理生根情况进行综合评价。结果表明:(1)落羽杉插穗皮部和愈伤组织处均有不定根伸出,两处不定根数量分别占不定根总数的63.9%和36.1%;(2)4种外源激素中,吲哚丁酸(IBA)+萘乙酸(NAA)(等质量比)和IBA处理的插穗生根效果最好,NAA处理次之,生根粉(ABT)处理效果最差;(3)5种浓度(50 mg/L、100 mg/L、150 mg/L、200 mg/L和250 mg/L)之间的处理效果无显著差异;(4)4种处理时间(2 h、4 h、6 h和8 h)中,4 h处理的插穗生根效果最佳;(5)26个处理组合中,(IBA+NAA)×150 mg/L×4 h处理组合和NAA×250 mg/L×4 h处理组合的平均隶属函数值最高,分别为0.83和0.82,清水对照的平均隶属函数值最低,为0.05。研究初步验证了皮部生根是落羽杉大龄母树插穗的主要生根方式,筛选出三峡消落带原位适生落羽杉大龄母树插穗扦插的两种较佳处理组合为(IBA+NAA)×150 mg/L×4 h和NAA×250 mg/L×4 h。

摘要：采用原位合成的方法设计并制备了SiC BN复合陶瓷。经理论计算及实验证明 ,在相对较低的温度(170 0°C)下即可成功实现预期的原位反应。复合陶瓷中生成了细小均匀的微米级SiC和BN颗粒 ,在添加剂较多的地方发现了纳米级的SiC晶粒。SiC BN系列复合陶瓷的抗弯强度和断裂韧性在含 2 0vol%BN时达到最大 ,分别为 311MPa和 4 .5MPa·m1 2 ,弹性模量和硬度随BN含量的增加而减小 ,B6 0复合陶瓷的弹性模量为 4 0 .8GPa,维氏硬度为 0 .5 5GPa。不含BN的B0复合陶瓷的断裂方式主要为穿晶断裂 ,含有BN的SiC BN复合陶瓷的断裂方式主要为沿晶断裂。

摘要：网络文化作为一种新型的文化形态,扩展了思想教育的平台、充实了教育对象的心理空间。与此同时,网络文化也在语言文化、价值观念、道德人格和人际情感方面对思想道德教育带来了巨大挑战。因此,在网络文化背景下,思想教育者在加强网络阵地建设、营造"绿色"网络文化环境同时,要加强对学生传统文化、民族精神和网络道德等方面的教育,开创学生思想道德教育新局面。

摘要：针刺密度、针刺深度等针刺工艺会对纤维针刺预制体的性能造成显著影响。本文通过有限元分析方法,利用Python语言对ABAQUS软件进行二次开发,建立了玄武岩纤维针刺预制体的代表性体积单元(RVE)。研究了针刺深度和针刺密度对玄武岩纤维针刺预制体层间力学和热导率的影响,并结合实验结果分析了其影响机制。结果表明,不同纤维网胎层间主要依靠针刺纤维进行结合,增加针刺密度和针刺深度均可提高针刺预制体的剪切性能,但提高针刺密度的效果比提高针刺深度的效果更加明显。当沿针刺预制体z轴方向施加温度梯度时,热流矢量主要集中于针刺纤维中,且当增加针刺深度时上述现象更加明显。因此,增加针刺深度不利于针刺预制体的防热性能。

摘要：针对具体顺层岩质边坡,利用极限平衡理论得到了边坡的安全系数K_(S)与软弱夹层距坡肩距离d的关系(K_(S)-d)曲线,再用数值模拟的方法,基于Geo-slope软件对所用解析计算公式及K_(S)-d曲线进行校验,从而确定了在满足安全系数要求下的顺层边坡的关键软弱夹层,也即为锚固的持力段与自由段的界面,进而优化了锚索的长度。而后结合锚索受力机制的研究,运用FLAC^(3D),模拟了不同锚固排距(l)下的边坡安全系数(K_(S)),得到K_(S)-l曲线,从而确定了最佳锚固排距。以此为基础建立优化后的边坡锚固模型,再应用FLAC^(3D)进行边坡稳定性分析,并通过锚索的最大轴力反算以校核锚索的材料参数,通过锚固水泥浆体所受的剪力正负分界面,以判断潜在主滑移面的位置及特征。优化后的方案符合安全规范,比原设计方案节省了较大比例的工程量,对该矿今后大面积的边坡加固有重大的经济价值,对类似边坡工程有一定的参考意义。