Effect of Y concentration and film thickness on microstructure and electrical properties of HfO2 based thin films

In this work, we introduced a simple solution processing method to prepare yttrium (Y) doped hafnium oxide (HfO₂) based dielectric films. The films had high densities, low surface roughness, maximum permittivity of about 32, leakage current < 1.0 × 10^?7 A/cm² at 2 MV/cm, and breakdown field >5.0 MV/cm. In addition to dielectric performance, we investigated the influence of YO_1.5 fraction on the electronic structure between Y doped HfO₂ thin films and silicon (Si) substrates. The valence band electronic structure, energy gap and conduction band structure changed linearly with YO_1.5 fraction. Given this cost-effective deposition technique and excellent dielectric performance, solution-processed Y doped HfO₂ based thin films have the potential for insulator applications.     

Chicken nuggets-like core/shell nanosheet arrays as high performance flexible all-solid-state supercapacitor cathode and buckwheat shell as anode

The energy density of a flexible all-solid-state supercapacitor (ASC) requires new electrode material with special structure and morphology as a prerequisite for its secured improvement. In this paper, a new morphological exploration of chicken nuggets-like core/shell NiCo₂O₄/MnO₂ (NCM) nanosheet arrays on Ni foam was employed. The application of this special morphology aims to greatly improve the electrochemical performance of the cathode electrode. Additionally, Buckwheat Biochar (BBC) is utilized as the anode while the PVA/KOH thin film is prepared as the separator. The chicken nuggets-like core/shell NCM nanosheet arrays were obtained by a two-step hydrothermal method. A series of characterization methods were carried out to further support the core/shell's well-designed structure and precise composition. The tests exhibited excellent specific capacitance of 593.3 F g^?1 at 5 mA cm^?2 and outstanding cycling stability with a retention of 90% after 10000 cycles. Furthermore, the assembled NCM//BBC ASC device indicated a high specific capacitance (239 F g^?1 at the current density of 5 mA cm^?2), this is in due part of the unique architecture of NCM nanosheet arrays and interconnected special porous structure of the BBC and the thin film PVA/KOH. Hence, the assembled ASC device exhibited high energy density (an energy density of 58 Wh·kg^?1 at 3263 W kg^?1) and remarkable cycling stability.     

智能混凝土施工及其应用

随着时代的发展,相关从业者对智能混凝土的研究越来越深入.在实际工程推进中,智能混凝土施工的优势非常明显,可以很好地提高混凝土的性能,并根据施工的需求做好混凝土的优化控制工作,让施工单位可以结合项目的实际应用需求,有针对性地选择对应的智能混凝土施工工艺.     

Advances in statistical mechanics of rock masses and its engineering applications

To efficiently link the continuum mechanics for rocks with the structural statistics of rock masses,a theoretical and methodological system called the statistical mechanics of rock masses(SMRM)was developed in the past three decades.In SMRM,equivalent continuum models of stressestrain relationship,strength and failure probability for jointed rock masses were established,which were based on the geometric probability models characterising the rock mass structure.This follows the statistical physics,the continuum mechanics,the fracture mechanics and the weakest link hypothesis.A general constitutive model and complete stressestrain models under compressive and shear conditions were also developed as the derivatives of the SMRM theory.An SMRM calculation system was then developed to provide fast and precise solutions for parameter estimations of rock masses,such as full-direction rock quality designation(RQD),elastic modulus,Coulomb compressive strength,rock mass quality rating,and Poisson’s ratio and shear strength.The constitutive equations involved in SMRM were integrated into a FLAC3D based numerical module to apply for engineering rock masses.It is also capable of analysing the complete deformation of rock masses and active reinforcement of engineering rock masses.Examples of engineering applications of SMRM were presented,including a rock mass at QBT hydropower station in northwestern China,a dam slope of Zongo II hydropower station in D.R.Congo,an open-pit mine in Dexing,China,an underground powerhouse of Jinping I hydropower station in southwestern China,and a typical circular tunnel in Lanzhou-Chongqing railway,China.These applications verified the reliability of the SMRM and demonstrated its applicability to broad engineering issues associated with jointed rock masses.     

In situ Raman spectroscopic study towards the growth and excellent HER catalysis of Ni/Ni(OH)2 heterostructure

The electrochemical water splitting to produce H₂ in high efficiency with earth-abundant-metal catalysts remains a challenge. Here, we describe a simple “cyclic voltammetry + ageing” protocol at room temperature to activate Ni electrode (AC-Ni/NF) for hydrogen evolution reaction (HER), by which Ni/Ni(OH)₂ heterostructure is formed at the surface. In situ Raman spectroscopy reveals the gradual growth of Ni/Ni(OH)₂ heterostructure during the first 30 min of the aging treatment and combined with polarization measurements, it suggests a positive relation between the Ni/Ni(OH)₂ amount and HER performance of the electrode. The obtained AC-Ni/NF catalyst, with plentiful Ni–Ni(OH)₂ interfaces, exhibits remarkable performance towards HER, with the low overpotential of only 30 mV at a H₂-evolving current density of 10 mA/cm² and 153 mV at 100 mA/cm², as well as a small Tafel slope of 46.8 mV/dec in 1 M KOH electrolyte at ambient temperature. The excellent HER performance of the AC-Ni/NF could be maintained for at least 24 h without obvious decay. Ex situ experiments and in situ electrochemical-Raman spectroscopy along with density functional theory (DFT) calculations reveal that Ni/Ni(OH)₂ heterostructure, although partially reduced, can still persist during HER catalysis and it is the Ni–Ni(OH)₂ interface reducing the energy barrier of H1 adsorption thus promoting the HER performance.     

耦合双涵道风机的双擎换热系统设计优化

基于航空领域双涵道设计的风机系统,应用于房间空调器,解决单一类型风机存在的风感问题,能有效提升人体舒适性.但耦合双涵道风机的双擎换热系统设计,国内外尚无相关研究.为了研究双擎换热系统匹配设计方法,总结设计规律,通过对耦合双涵道风机的换热系统进行数值仿真和实验研究,获取不同负载条件下,双涵道风机系统上下风机最佳转速配比参数,同时匹配全新换热器结构参数,规划管内侧制冷剂分布,强化双擎换热系统换热效率,提升空调器的能效等级,以满足高能效的用户需求.     

基于蛋白质组学技术研究秦川牛肉宰后贮藏过程中肌红蛋白含量及其衍生物转化

本实验采用4D-非标记蛋白质组学技术研究秦川牛肉贮藏过程中（0～8 d）肌红蛋白含量及其衍生物的转化情况，阐释冷却秦川牛肉中肌红蛋白含量及其衍生物转化的分子机制。结果表明：贮藏过程中，肌红蛋白表达量在宰后0～4 d上升、4～8 d下降，利用非标记蛋白质组学技术鉴定出与肌红蛋白及其衍生物相关的差异蛋白14 种，具体包括代谢酶、氧化还原酶、过氧化物酶、伴侣蛋白4 类，这4 类蛋白的表达共同调控贮藏过程中肌红蛋白含量的变化及其3 种衍生物之间的转化，具体表现为贮藏过程中肌红蛋白表达量整体呈下降趋势，氧合肌红蛋白相对含量持续下降，脱氧肌红蛋白、高铁肌红蛋白相对含量逐渐增加，导致肉色发生褐变。本研究结果有利于理解秦川牛肉贮藏过程肉类变色的复杂生化变化机制。     

Comparison of γ-aminobutyric acid accumulation capability in different mung bean (Vigna radiata L.) varieties under heat and relative humidity treatment,and its correlation with endogenous amino acids and polyamines

In this study, the accumulation of GABA and its inherent factors across different varieties of mung bean (Vigna radiata L.) in response to heat and relative humidity (HRH) were investigated. Results showed the average GABA content in mung bean varieties was increased 7.52 times following HRH treatment, and the black mung bean variety (A8) exhibited the highest GABA accumulation capability (1.76–84.57 mg per 100 g DW). From the perspective of GABA shunt metabolites, the free glutamic acid content of mung beans significantly decreased (P < 0.05) after HRH treatment and presented a significant correlation (P < 0.05) with GABA content. In polyamine degradation pathway, although the average levels of spermine and spermidine of mung bean varieties significantly decreased (P < 0.05) after HRH treatment, no significant correlation with GABA content was identified. Hence, the GABA accumulation was predominantly attributed to GABA shunt. Besides, free amino acids including glutamic acid, serine, ornithine, arginine and glycine in mung beans showed a significant positive correlation (P < 0.05) with GABA content and increment following HRH treatment, which suggested that mung beans enriched in these free amino acids might accumulate higher amounts of GABA after HRH treatment and be useful for industrial applications.     

Fluoride-mediately solvothermal synthesis and tunable photocatalytic selectivity of urchin-like ZrO2 hollow microspheres

Photocatalysts often show excellent performances on the basis of their surface state of exposed faces with high reactivity, but unfortunately surfaces of this type are usually concealed into the interior of crystals for their high surface energy. We report here a possibility that for fluorine-terminated surfaces of monoclinic ZrO₂, these higher-energy surfaces could be retained and exposed. Urchin-like ZrO₂ hollow microspheres (UZHS) composed of nanoribbons with exposed (010) facets are obtained through a fluoride mediately solvothermal method. We prove the stabilization effect of fluorine adsorption on (010) facets by density functional theory calculations. More interestingly, UZHS exhibit tunable photocatalytic selectivity in dye degradation. The fluorinated UZHS exhibit good performances both on decomposing Congo red (CR) and methylene blue, while the surface-modified UZHS by calcination only favor decomposition of CR.