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1.
《Ceramics International》2021,47(19):27487-27495
ZnO nanorod arrays (NRs) with a large number of sharp tips and uniform shapes were grown on the carbon cloth (CC) by a simple hydrothermal method. Titanium nitride (TiN) nanoparticles with various thicknesses were deposited on the ZnO NRs by magnetron sputtering to obtain ZnO/TiN core-shell arrays. Field emission (FE) performance of ZnO NRs show close dependence on TiN coating thickness. The turn-on field first decreases and then increases with increasing TiN coating thickness from 60 nm to 300 nm. The arrays with a design architecture can strike a balance between increased emission sites and limited field shielding effects. ZnO/TiN240 core-shell NRs have the lower turn-on electric field at 0.79 V/μm and the higher current densities at 9.39 mA/cm2. The field enhancement factor (β) of ZnO/TiN240 is about 3.2 times that of the bare ZnO NRs. On the other hand, the electrochemical properties were improved due to the formation of core-shell heterojunction on the ZnO/TiN interface and porous structure, which makes the ion and charge transport more convenient. Hence, this work not only revealed that the ZnO/TiN core-shell structure exhibited excellent improvement in both FE and supercapacitors applications, but also that growing arrays on CC was expected to achieve flexible display.  相似文献   
2.
结合杭州市低影响开发区对雨水控制的要求,运用SWMM模型模拟常规开发模式、组合LID设施、组合LID+蓄水池对雨洪控制的效果。研究结果表明,组合LID设施可以有效降低场地内洪峰流量、径流系数,并使场地在50 a重现期以下的降雨情况无溢流节点;组合LID+蓄水池可以控制杭州市100 a重现期2 h短历时降雨量的94.3%,削减洪峰径流量84.5%,但对杭州市100 a重现期24 h长历时降雨量控制径流为70%,略小于74.5%的设计目标。  相似文献   
3.
李琛 《江苏建材》2021,(2):54-55
概述了水泥行业碳排放的主要来源,分析了目前水泥工业碳减排的主要渠道,指出错峰生产和产能减量置换政策已成为压减水泥过剩产能的两大政策抓手。  相似文献   
4.
针对不满足忠实分布的高维数据分类问题,一种新的基于粒子群算法的马尔科夫毯特征选择方法被提出。它通过有效地提取相关特征和剔除冗余特征,能够产生更好的分类结果。在特征预处理阶段,该算法通过最大信息系数衡量标准对特征的相关度和冗余性进行分析得到类属性的马尔科夫毯代表集和次最优特征子集;在搜索评价阶段,采用新的适应度函数通过粒子群算法选出最优特征子集;用此模型对测试集进行预测。实验结果表明,该算法在12个数据集上具有一定的优势。  相似文献   
5.
The trivalent rare-earth (RE3+) doped phosphors show tremendous achievement in narrow band multicolor line emission for various applications. However, the 4f–4f absorption transition of these ions is forbidden in UV and blue light excitation. Usually, a sensitizer having spin allowed transition was used as a co-dopant to excite these ions via the energy transfer phenomenon. Another approach promisingly using to excite these ions by efficient energy transfer from the intrinsic emission of the Ca2LuTaO6 double perovskite phosphors host lattice. Phosphors of Ca2LuTaO6 with double perovskite structure were synthesized by using a high-temperature solid-state reaction method. The produced Ca2LuTaO6 double perovskite phosphors show an intrinsic broad band emission centered at 424 nm under the excitation of 313 nm UV light. The origin of this broad band blue emission was deeply investigated by using computation and experimental approaches. The trivalent activator Dy3+ and Eu3+ were doped is a single and co-dopant in the produced Ca2LuTaO6 phosphors to check their excitation in UV and near-UV spectral region. X-ray diffraction and scanning electron microscopy were used to investigate the structure and phase analysis. Various characterizations such as photoluminescence excitation, emission, and CIE chromaticity coordinates were measured which illustrate the potential of Dy3+ and Eu3+ activated Ca2LuTaO6 double perovskite phosphors for narrow band multicolor line emission for various applications.  相似文献   
6.
为了实现车辆制动模拟试验中附着系数的准确模拟和实时可调,设计了一种汽车制动模拟试验台,通过控制磁粉离合器励磁电流,实时模拟不同路面附着系数;搭建了基于路面识别的单轮车辆制动系统仿真模型,进行了单一路面和跃变路面下的制动仿真;研制了车辆制动模拟实验系统,开展了单一路面下汽车制动模拟实验和跃变路面下附着系数跟踪控制实验。研究结果表明,在湿沥青路面上以120 km/h初速度制动时,相比于基于固定目标滑移率,基于路面识别的最佳滑移率下的制动距离缩短了3.1%,且在低附着路面下更为明显;单一路面下制动时车速和轮速的实验值与仿真值基本吻合;跃变路面下附着系数最大跟踪误差仅为6.2%,跟踪控制效果良好。  相似文献   
7.
An acoustic emission (AE) experiment was carried out to explore the AE location accuracy influenced by temperature. A hollow hemispherical specimen was used to simulate common underground structures. In the process of heating with the flame, the pulse signal of constant frequency was stimulated as an AE source. Then AE signals received by each sensor were collected and used for comparing localization accuracy at different temperatures. Results show that location errors of AE keep the same phenomenon in the early and middle heating stages. In the later stage of heating, location errors of AE increase sharply due to the appearance of cracks. This provides some beneficial suggestions on decreasing location errors of structural cracks caused by temperature and improves the ability of underground structure disaster prevention and control.  相似文献   
8.
ABSTRACT

Preparation of poly(thiophene-alt-pyrrole bearing mesogen) was carried out with Migita–Kosugi–Stille coupling type polycondensation with an aid of Pd(0) complex catalyst. The resultant polymer shows lyotropic liquid crystallinity with good film-forming property. The smectic fan-shaped texture is maintained after completion of evaporation of solvent from the polymer solution. The cast film having liquid crystal (LC) order shows light emission function upon irradiation of excitation light at 460 nm. The polymer shows LC domain emission. Mechanical orientation allows to yield LC domain aligned film with band structure. Chiral mesogenic side chain induces π-conjugated main chain helicity from distance in molecular level.  相似文献   
9.
Yb3+/Er3+codoped La10W22O81 (LWO) nanophosphor rods have been successfully synthesized by a facile hydrothermal assisted solid state reaction method, and their upconversion photoluminescence properties were systematically studied. X-ray diffraction patterns revealed that the nanophosphors have an orthorhombic structure with space group Pbcn (60). A microflowers-like morphology with irregular hexagonal nanorods was observed using field emission scanning electron microscopy for the Yb3+(2 mol%)/Er3+(2 mol%):LWO nanophosphor. The shape and size of the nanophosphor and the elements along with their ionic states in the material were confirmed by TEM and XPS studies, respectively. A green upconversion emission was observed in the Er3+: LWO nanophosphors under 980 nm laser excitation. A significant improvement in upconversion emission has been observed in the Er3+: LWO nanophosphors by increasing the Er3+ ion concentration. A decrease in the upconversion emission occurred due to concentration quenching when the doping concentration of Er3+ ions was greater than 2 mol%. An optimized Er3+(2 mol%): LWO nanophosphor exhibited a strong near infrared emission at 1.53 μm by 980 nm excitation. The green upconversion emission of Er3+(2 mol%): LWO was remarkably enhanced by co-doping with Yb3+ ions under 980 nm excitation because of energy transfer from Yb3+ to Er3+. The naked eye observed this upconversion emission when co-doping with 2 mol% Yb3+. In order to obtain the high upconversion green emission, the optimized sensitizer concentration of Yb3+ ions was found to be 2 mol%. The upconversion emission trends were studied as a function of stimulating laser power for an optimized sample. Moreover, the NIR emission intensity has also been enhanced by co-doping with Yb3+ ions due to energy transfer from Yb3+ to Er3+. The energy transfer dynamics were systematically elucidated by energy level scheme. Colorimetric coordinates were determined for Er3+ and Yb3+/Er3+: LWO nanophosphors. The energy transfer mechanism was well explained and substantiated by several fluorescence dynamics of upconversion emission spectra and CIE coordinates. The results demonstrated that the co-doped Yb3+(2 mol%)/Er3+(2 mol%): LWO nanophosphor material is found to be a suitable candidate for the novel upconversion photonic devices.  相似文献   
10.
均三甲苯是一种重要的化工原料,通常存在于重整重芳烃中,其中均三甲苯与偏三甲苯、邻甲乙苯的分离较为困难。测定了2 kPa下均三甲苯(1)-偏三甲苯(2)、均三甲苯(1)-邻甲乙苯(3)两个体系的汽液相平衡数据,并分别采用NRTL和UNIQUAC活度系数模型对相平衡数据进行关联,回归获得二元交互参数,并进行了热力学一致性检验。结果表明,在2 kPa下,均三甲苯与邻甲乙苯无法通过普通精馏实现分离。通过对均三甲苯-偏三甲苯-邻甲乙苯体系进行烷基化反应,而后分别采用单塔减压精馏和双塔减压精馏对反应产物的分离进行精馏模拟,得出较优工艺为双塔连续减压精馏,两塔塔板数分别为50,回流比分别为7和8,此时均三甲苯纯度可达98%(质量)。该研究不仅补充了汽液相平衡数据库,也为低压下C9体系的分离工艺设计提供参考。  相似文献   
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