Experimental evidence of structural evolution for TiB2 microcrystal under externally high stresses

The morphology evolution and defect structure of TiB₂ microcrystals treated under high stresses were analyzed using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results show that hexagonal TiB₂ with large particle size gradually evolved to flowerlike TiB₂ with small particle size under high stresses. The evolution process is mainly determined by the preferential cleavage of TiB₂ microcrystal, and the presence of multiple lamellar nanotwin and edge dislocation directly provides some evidence of plastic deformation and structural evolution. For clarity, a possible model is suggested based on the HTREM observation and the natural properties of TiB₂ materials to explain the process mechanism.     

远程视频监控系统中DS/FH混合扩频技术研究

远程视频监控系统中提高系统的可靠性和稳定性很重要。针对这一问题提出在系统中采用DS/FH混合扩频技术。详细讨论了采用DS/FH混合扩频通信技术系统的抗宽带阻塞干扰、多径干扰性能,并通过SYSTEMVIEW仿真软件进行仿真分析,分析和仿真结果表明了采用此技术的可行性。给出了该通信模式下的系统模型,为实际系统的设计与实现奠定了基础。     

各向异性软黏土地基上浅基础破坏包络面研究

 根据已有的关于土体强度各向异性的表达式,针对基于Tresca屈服准则的理想弹塑性模型进行改进,使之可以考虑不排水条件下软黏土强度的各向异性,并在大型通用有限元软件ABAQUS中予以数值实施。联合应用swipe加载模式和固定位移比加载模式,对于条形浅埋基础在竖向荷载V、水平荷载H与力矩荷载M的复合加载条件下的承载性能进行比较系统的数值模拟,主要探讨地基土不排水强度的各向异性、竖向荷载水平对于浅基础在H-M荷载空间内的破坏包络面的影响。首先进行浅基础分别在竖向、水平与力矩荷载单独作用下极限承载力的计算,并与已有结果进行对比。进而对于不同竖向荷载水平下浅基础在H-M荷载空间内的破坏包络面特性进行分析。计算结果表明：当浅基础埋深与宽度之比较大或基础承受三维自由度加载时,swipe加载模式得到的加载路径比真实的破坏包络面明显偏小;对于给定埋深的浅基础,其包络面的大小与地基土强度的各向异性与竖向荷载水平都有关系,而在归一化荷载平面内,包络面形状主要受到竖向荷载水平的影响,而与地基土强度的各向异性无关。     

基于遗传算法的建设工程风险决策多目标优化研究

在建设工程风险决策过程中,只考虑单个目标因素的决策并不能满足实际工程的要求。为了使决策更加科学、合理,在风险识别和风险评价的基础上,综合考虑包括风险管理成本在内的多个目标因素对决策结果的影响,建立了工程风险多目标决策优化模型,通过多目标遗传算法NSGA-Ⅱ,实现了工程风险决策方案的优化。最后,对优化结果的分析和评价,证明了所建立的模型在解决工程风险决策问题上的有效性和实用性。     

一种抗辐射危害和缓解视疲劳保健食品的研制

目的研制既能防止辐射危害又能缓解视疲劳的保健食品。方法以枸杞、菊花和葡萄籽为原料，经科学配伍加工制作，并进行毒理实验和功能评价。结果制成保健食品片剂。结论此产品具有抗辐射危害和缓解视疲劳的作用，安全无毒，可长期服用。     

Single atom iron carbons supported Pd–Ni–P nanoalloy as a multifunctional electrocatalyst for alcohol oxidation

Exploring high-performance and multifunctional electrocatalysts for alcohols oxidation is the key to develop alkaline fuel cells. Herein, we prepared a novel palladium-nickel-phosphorus catalyst supported on single atom iron carbons (SAICs) with different diameter sizes (1000 nm, 200 nm, 100 nm, 50 nm, and 20 nm), which were synthesized by direct carbonization of Fe-doped Zeolitic Imidazolate Framework-8 (ZIF-8). Electrochemical tests reveal that the as-prepared PdNiP/50nmSAIC exhibited excellent electrooxidation activity and stability to the various alcohols (methanol, glycerol, and especially ethylene glycol) electrooxidation in the alkaline solution, which is much higher than that of commercial Pd/C and other advanced Pd-based catalysts. Meanwhile, the rotating disk electrode (RDE) and CO-stripping results proves that PdNiP/50nmSAIC possesses a faster kinetic process of ethylene glycol oxidation and enhanced anti-CO poisoning ability. Our efforts provide a new strategy for the development of MOFs-derived multielement electrocatalyst with excellent activity and stability, and a bright future for alcohol oxidation.     

超临界二氧化碳再压缩布雷顿循环多目标优化

建立超临界二氧化碳再压缩布雷顿循环多目标优化模型,研究分流系数、循环压比、主压缩机吸气压力和膨胀机入口温度对系统性能的影响规律,并进行综合评价.结果表明:随着分流系数的增大,多目标函数先增大后减小,同时分流系数具有最优值;随着主压缩机吸气压力的增加,多目标函数和系统热效率均降低;膨胀机入口温度越高,多目标函数越小;4个...     

研究生创新能力平台的构建与实施

通过建立研究生联合培养基地,整合企业与高校的教育资源,构建研究生创新能力平台,可提高研究生的实践与创新能力。本文详细探讨了构建研究生创新能力平台的具体实施方案。     

An information-theoretic evaluation of narrative complexity for interactive writing support

Narrative complexity should be managed systematically during the creation process because it heavily influences the levels of understanding and the interest of recipients. Existing research has tended to depend on impressionist criticism or to deal with narrative complexity at general and superficial levels. In this paper, we consider the creation and acceptance of narrative as information processing mediated by a narrative text. Under this assumption, we propose a method to quantitatively evaluate narrative complexity at the recipient's cognitive level, and to effectively utilize the evaluation to aid in the author's narrative creation process. Within our knowledge distribution model, a narrative is represented as a knowledge structure, and the knowledge state and knowledge flow of narrative agents are evaluated using a probabilistic reasoning model. From the knowledge flows, the amount of information processed and required by the recipient is calculated as a measure of the narrative complexity using entropy theory. As a case study, we conduct a comparative analysis of an actual cinematic narrative and a structurally manipulated version of that narrative to show how the method captures characteristics and changes of the narrative; we also discuss the improvements presented in this paper as compared to our previous research.     

基于VF信息管理系统的研究

随着科学技术的不断进步以及高等教育的普及,学校规模的不断扩大导致学生信息量也是很复杂繁多,而如果仍然采用传统式的学生信息管理方法就不可避免的浪费大量人力、物力和财力资源,而且不能满足当代中国教育的发展需求,现在这一问题已经成为势必要解决的问题。信息管理系统是一种融合管理科学、信息科学、系统科学、现代通信技术和电子计算机技术为一体的综合性先进管理手段。随着科学技术和管理系统无论在理论还是技术上的不断改进与完善,其所展现出的优势和进步空间充分说明了存在的必要性,有效地提高管理效率。