Thermal properties of hierarchical YSZ and LZO ceramic microspheres with multi-scaled voids investigated by using theoretical,experimental and simulation methods

Heat transfer within ceramic feedstock powders is still unclear, which impedes optimization of the thermal and mechanical properties of the thermal sprayed coatings. The microspheres (yttria-stabilized zirconia YSZ and lanthanum zirconate LZO) were prepared via the electro-spraying assisted phase inversion method (ESP). The thermal properties of the two ESP microspheres and a commercial hollow spherical powder (HOSP) were investigated by using theoretical, experimental, and simulation methods. Thermal conductivity of the single microsphere was estimated via a novel nest model that was derived from the Maxwell-Eucken 1 and the EMT model. Thermal conductivity of a single YSZ/LZO-ESP microsphere prepared at 1100–1200 °C was within 0.36–0.75 W/m K, which was ～ 20 % lower than that of a single YSZ-HOSP microsphere with a similar porosity. Heat flux simulation showed that high tortuosity around the multi-scaled voids of the ESP microsphere led to a more efficient decrease in thermal conductivity compared with total porosity.     

电气化铁路既有线深路堑扩堑石方控制爆破

介绍电气化铁路既有线无隔墙台阶爆破扩堑方法。沿既有线方向设置低台阶 ,边界处布置光爆孔 ,采用“同列同段和列间微差”的起爆网路。采用自制的“炮被”和架设“钢管排架”阻挡飞石、滚石和滑石 ,确保了既有线的安全。文中还概述了“炮被”和“钢管排架”的制做以及作者的认识和体会。     

应用型本科高校生物技术专业课程设置改革的思考

地方应用型本科生物技术专业课程设置的重点应该着重于发挥基础特长和应用型实践。目标定位于合乎自身特点,具有鲜明特色性的品牌专业。     

Type-II AsP/Sc2CO2 van der Waals heterostructure: an excellent photocatalyst for overall water splitting

In this work, we explore the application potential of AsP/M₂CO₂ (M = Sc, Zr) van der Waals heterostructures in photocatalytic water splitting through the first-principles calculations. The calculated results show that AsP/Zr₂CO₂ heterostructure possesses an unfavorable type-Ⅰ band alignment, whereas AsP/Sc₂CO₂ exhibits a desirable type-Ⅱ band alignment, which is beneficial for separating the photogenerated electron-hole pairs. Also, the band edge positions of AsP/Sc₂CO₂ heterostructure stride the redox potential of water, ensuring favorable reaction kinetics. Besides, the strong optical absorption of AsP/Sc₂CO₂ heterostructure in both visible and ultraviolet regions (especially up to 10⁻⁶ cm⁻¹ at about 250 nm) makes it possible to utilize solar energy effectively. Meanwhile, AsP/Sc₂CO₂ heterostructure has an exciton binding energy as low as 0.09 eV, which quantitatively illustrates the high separation efficiency of photogenerated charge carrier. Thus, the type-Ⅱ band alignment, suitable band edge position, strong light absorption, and low exciton binding energy together indicate that AsP/Sc₂CO₂ heterostructure is a potential photocatalytic material. In addition, the obvious redshift phenomenon in the optical spectrum of AsP/Sc₂CO₂ heterostructure shows that biaxial strain can improve its light capture capability. Also, the interconversion between type-Ⅱ and type-Ⅰ can be achieved by applying different strains. All these findings suggest that the novel AsP/Sc₂CO₂ heterostructure has significant application prospects in next-generation photovoltaic and photocatalytic devices.     

Evaluation of adult and offspring thiamine deficiency in salmonine species from Lake Ontario

Thiamine Deficiency Complex (TDC) is an ongoing problem impacting salmonine health in various waterbodies, including Lake Ontario. The prevalence of TDC has been variable and explanations for differences are limited. In the current study, thiamine concentrations were measured in eggs, liver tissue, and muscle tissue sampled from brown trout (Salmo trutta), Chinook salmon (Oncorhynchus tshawytscha), coho salmon (O. kisutch), lake trout (Salvelinus namaycush), and steelhead trout (O. mykiss) that were collected from Lake Ontario and its surrounding tributaries. The occurrence of TDC was measured for each species based on TDC-induced offspring mortality rates under laboratory conditions. TDC-induced offspring mortality was observed for all species except brown trout. For affected species, egg free thiamine (Th) was consistently low compared to lake trout collected from Lake Superior that are considered thiamine replete. In addition, species with the lowest percentages of Th in their eggs were the most susceptible to TDC, suggesting that limited thiamine reserves in the form of Th may cause TDC-induced offspring mortality. Lastly, our results show that egg thiamine concentrations have yearly variation and increased for all species throughout the study. Reasons for such variation are undetermined; but, if egg thiamine concentrations continue to increase, the impacts of TDC on these salmonine species may lessen. Future monitoring is needed for determining if thiamine concentrations are increasing and the potential impacts that may have on the entire Lake Ontario fishery.     

Impact of urban development on residents’ public transportation travel energy consumption in China: An analysis of hydrogen fuel cell vehicles alternatives

Urban development has an important influence on the energy consumption of transportation. To develop public transportation is one of the important ways to decrease the energy consumption of urban transportation. It is very urgent to upgrade technology to reduce the energy consumption and emissions of the vehicles constantly. The popularization of hydrogen fuel cell vehicles is the trend of the future automobile industry, which can effectively reduce traffic energy consumption and alleviate urban pollution. This article analyzes the impact of urban development on public transport and private transportation energy consumption from 2013 to 2015; and uses hydrogen fuel cell vehicles alternatives in urban public transport as a scenario. It shows that urban economic development can effectively reduce public transport. Population growth will increase greatly energy consumption of public transport, while larger cities with reasonable spatial density can reduce traffic energy consumption. Moreover, hydrogen fuel cell vehicles can effectively reduce the energy consumption and pollution emissions of urban transportation during operating. Based on the above conclusions, this article will eventually provide targeted recommendations for the development of Chinese cities, public transport, and hydrogen fuel cell vehicles.     

Unconditional stability and error estimates of the modified characteristics FEMs for the time-dependent incompressible MHD equations

This paper focuses on the unconditional stability and convergence of characteristics type methods for the time-dependent incompressible MHD equations. For this purpose, we introduce a new characteristics time-discrete system. The optimal error estimates in $L^2$ and $H^1$ norms for the typical modified characteristics finite element method unconditionally can be deduced, while the whole previous works require certain time-step restrictions. Some numerical experiments document performance of the characteristics type methods for the time-dependent incompressible MHD equations.     

采用信息增益率的混合入侵检测模型设计

针对现有混合入侵检测模型仅定性选取特征而导致检测精度较低的问题，同时为了充分结合误用检测模型和异常检测模型的优势，提出一种采用信息增益率的混合入侵检测模型.首先，利用信息增益率定量地选择特征子集，最大程度地保留样本信息；其次，采用余弦时变粒子群算法确定支持向量机参数构建误用检测模型，使其更好地平衡粒子在全局和局部的搜索能力，然后，选取灰狼算法确定单类支持向量机参数构建异常检测模型，以此来提高对最优参数的搜索效率和精细程度，综合提高混合入侵检测模型对攻击的检测效果；最后，通过两种数据集进行仿真实验，验证了所提混合入侵检测模型具有较好的检测性能.     

碳源对manA基因突变大肠杆菌代谢的影响

ManA基因编码的甘露糖-6-磷酸异构酶在大肠杆菌中催化D-甘露糖和D-果糖的异构化,促进大肠杆菌对碳源的代谢吸收。本文通过研究manA基因突变大肠杆菌对碳源的利用和编码糖代谢基因情况,探讨甘露糖-6-磷酸异构酶对大肠杆菌糖代谢的影响。采用Ⅱ型内含子逆转录突变方法构建manA基因突变大肠杆菌,分析manA基因突变大肠杆菌对不同碳源的利用情况和manA基因突变对大肠杆菌糖代谢相关基因表达的影响,结果显示,大肠杆菌BL21(DE3)ΔmanA以甘露糖、果糖为碳源时,菌株生长受到显著抑制;以淀粉为碳源时,BL21(DE3)ΔmanA菌株的生长显著优于野生型大肠杆菌;以葡萄糖为碳源时,manA基因突变对大肠杆菌的生长无显著影响。通过基因表达分析,发现大肠杆菌BL21(DE3)ΔmanA中甘露糖代谢相关基因的表达显著性降低;果糖代谢途径中6-磷酸果糖激酶Ⅰ亚基的编码基因(pfkA)显著下调表达;水解淀粉的α-淀粉酶编码基因(malS)显著性上调表达。ManA基因突变影响大肠杆菌甘露糖、果糖和淀粉代谢途径中相关基因的表达,从而影响大肠杆菌对碳源的利用。