Evolution of microstructure,optical, and magnetic properties in multiferroic CuFe1-xSnxO2 (x = 0–0.05)

Evolution of the microstructure, optical, and magnetic properties have been investigated systematically in multiferroic CuFe_1-xSn_xO₂ (x?=?0–0.05) ceramics. Substitution of Sn⁴⁺ for Fe³⁺ results in expansion of CuFeO₂ lattice, and reduces the density of the material, but the metal oxidation states are unchanged. Observation of the optical properties shows that the value of the direct optical band gap (E_g) decreases with increasing Sn doping level, and that the CuFe_1-xSn_xO₂ (x?=?0–0.04) series with values >?3.1?eV. Magnetic susceptibility measurements show that Sn⁴⁺ doping decreases the Curie-Weiss temperature, i.e. weakens the strength of the antiferromagnetic interaction between high-spin Fe³⁺ ions, but does not affect the stability of the antiferromagnetic phase, and all samples undergo successive magnetic transitions at about T_N1 =?15?K and T_N2 =?11?K. However, magnetization curves show that changes occur in the magnetic interactions and both ferromagnetism and antiferromagnetism co-exist in the Sn⁴⁺-doped samples. The maximum value of the saturation magnetization of 1.8?emu·g^?1 was observed for the x?=?0.03 sample in a 2.5?kOe field. The changes in the magnetic behavior are closely related to the lattice distortion and charge compensation, which are discussed in detail in this work.     

Influence of physical and biological variability and solution methods in fruit and vegetable quality nondestructive inspection by using imaging and near-infrared spectroscopy techniques: A review

Over the past decades, imaging and spectroscopy techniques have been rapidly developing and widely applied in nondestructive fruit and vegetable quality assessment. The physical properties (including size, shape, color, position, and temperature) and biological properties (including cultivar, season, maturity level and geographical origin) of fruits and vegetables vary from one to another. A great variety of physical and biological properties of agricultural products influence the optical propagation properties and interaction behaviors with incident light, thus decreasing the quality inspection accuracy. Many attempts have been made in image correction and spectral compensation methods to improve the inspection accuracy. This paper gives a detailed summary about influence of physical and biological variability, as well as the correction and compensation methods for eliminating or reducing the effects in fruit and vegetable quality nondestructive inspection by using imaging and spectroscopy techniques. The advantages and disadvantages of the solution methods are discussed and summarized. Additionally, the future challenges and potential trends are also reported.     

Temperature Compensation Algorithm for Hydraulic System Pressure Control

In this paper the control mechanism of solenoid valve is analyzed, which shows the solenoid valve control is actually the control of coil current. The response characteristic of coil current is related to coil inductance and resistance. The coil resistance is influenced greatly by the ambient temperature and the self-heating of coil, which affects the control precision of coil current. First, considering the heat dissipation mode of coil, the coil temperature model is established from the perspective of heat conduction, and a temperature compensation algorithm for hydraulic system pressure control is put forward. Then the hardware-in-the-loop testbed is set up by using the dSPACE platform, carrying out wheel cylinder pressurization tests with inlet valve fully opened at -40℃ and 20℃, and testing the actual pressure of wheel cylinder with the target pressures at -40℃ and 6.000 kPa/s (pressurization rate). The results show that the pressure control temperature compensation algorithm proposed in this paper accurately corrects the influence of resistance temperature drift on the response accuracy of wheel cylinder pressure. After the correction, the pressure difference is less than 500 kPa, which can meet the control accuracy requirements of solenoid valve, enriching the linear control characteristic of solenoid valve.     

强风化砂岩边坡锚筋桩布置方式及支护作用研究

强风化顺层砂岩边坡具有节理裂隙发育、强度低的特征,导致开挖过程中出现边坡稳定问题。单纯的锚杆锚索支护无法满足边坡稳定性需求,在现场抗滑桩施工困难的情况下,选用经济、高效、施工便利的锚筋桩结合锚杆锚索对强风化顺层砂岩边坡进行支护。针对强风化砂岩破碎且强度低的特性,考虑高压注浆的劈裂作用,通过FLAC 3D数值模拟进行方案比选,得到适用于强风化砂岩边坡的锚筋桩多角度交叉布置方案。根据试验段边坡锚筋桩监测数据,分析强风化顺层砂岩边坡锚筋桩作用机理,验证了多角度交叉布置锚筋桩对强风化顺层砂岩边坡的加固效果。     

高边坡开挖卸荷过程强度折减法分析

针对露天矿开采过程中边坡变形破坏严重影响露天矿安全生产的问题，采用数值模拟的方法，应用MidasGTS NX软件建立重钢太和露天铁矿黄家山高边坡三维模型，进行开挖卸荷过程中的应力应变、位移及安全系数变化的数值模拟分析。结果表明：边坡岩体开挖卸荷过程中，随着采场的延深，边坡角的增大,塑性应力带的逐渐向边坡岩体内部扩大，风化破碎层及上部冰碛土层之间产生塑性应变贯通区，破坏面形成。开挖完成后整体边坡坡脚处发生剪切破坏，坡顶后缘形成张拉破坏区，边坡上部冰碛土层形成 “坐落—滑移”式滑动。边坡安全系数随向下开挖过程逐级降低，最终达到1.15稍显偏低。后期开采过程中，需对边坡中上部风化破碎岩层及冰碛土进行加固措施。     

杂填土边坡稳定性分析及其抗滑桩优化设计

以某建筑场地边坡的实际地质条件为基础,建立了边坡稳定性的FLAC 3D数值模拟模型,分别分析了有无支护3种工况下的边坡稳定性,研究了边坡安全稳定系数随抗滑桩加固位置、长度和桩间距的变化规律,给出了合理的抗滑桩设计方法。结果表明:(1)边坡的最大水平位移和竖向位移出现在素填土层的坡顶和坡中位置,无支护条件下难以满足安全储备要求;(2)合理的抗滑桩加固位置可以将边坡安全稳定系数提高到满足安全储备要求,抗滑桩的最佳加固位置为边坡中部距底坡水平距离为34m处;(3)边坡的安全稳定系数随抗滑桩长度的增大和桩间距的减小而增大,抗滑桩的最佳长度和间距分别为20m和8m。     

Sizing of multi-stage Op Amps by combining design equations with the gm/ID method

Analog integrated circuit design has as integral parts both analytical reasoning and numerical validation in the process from topology construction to sizing. Given a circuit topology, different circuit sizing results can be obtained from different processes of sizing inference. Sizing methods by simulation-based numerical searching have been a continuously studied subject. However, almost all approaches in this category require an overwhelming number of circuit simulations to arrive at an optimized sizing result. On the other hand, many published manual sizing methods by using the conventional device equations also require repeated SPICE simulations to correct the equation-based sizing results. This paper proposes a systematic gm/ID-based initial sizing method specifically customized for designing multiple-stage operational amplifiers (Op Amps). A main feature of the proposal is to use circuit-level design equations as constraints on the gm/ID table lookup method to substantially reduce the uncertainty in the sizing calculations. As a result, a significant amount of SPICE based correction work can be reduced to complete an initial sizing. The proposed sizing procedure includes a few regular sizing rules customized to the configuration of multi-stage Op Amps. We validate the proposed sizing method by application to several multi-stage Op Amp examples with a capacitive load or Miller compensation. Simulations have justified that the produced initial sizing results can achieve most of the prespecified design targets.     

Modelling multiphasic starch digestograms: an objective procedure for slope discontinuities†

Digestograms of 101 published in vitro starch digestion were used to investigate slope discontinuities. Polynomial equations (1 to 3 orders) adequately described the first derivative of the digestograms. The derivative(s) of the equations revealed critical point(s). The third-order equation described (P ≤ 0.05) 17% of the digestograms as triphasic, the second- and third-order equations identified (P ≤ 0.05) 32% as biphasic, while 51% exhibited (P ≤ 0.05) monophasic digestograms. Using nonlinear regression with practical constraints, a modified first-order kinetic model (D_t = D₀ + D_∞−0 {1 − exp [−K t]}) described (r² > 0.56, P ≤ 0.05) segments 1–3 of the digestograms. Rapid-slow and slow-rapid digestion rates were obtained, and maximum digestible starches, D_∞, ≤100g/100g (dry) starch for an in-depth understanding of starch digestion. This is the first comprehensive objective approach for slope discontinuities in starch digestograms for consistency in modelling digestograms that advances starch digestion studies.     

云南富宁良子老寨钛铁矿成矿规律和矿床成因

云南富宁地区钛铁矿是我国重要的钛铁矿矿床,成矿条件优越。本文对良子老寨矿区残坡积风化壳型钛铁砂矿床的地质特征、矿体、矿石特征进行了总结和研究,探讨了矿床的矿床成因和成矿规律。海西—印支期偏碱性基性钛辉辉长辉绿岩体为该区钛铁矿的形成提供了物质来源。富宁地区温热潮湿多雨气候有利于风化作用形成,岩体出露地表后,岩体中的钛矿物经风化剥离、水解作用、次生富集、原地残留或近距离搬运沉积,形成了残坡积风化壳型钛铁砂矿床。陡坡、临近河流区域矿体厚度薄,风化作用弱部位品位低;山脊缓坡、河谷阶地、地形低凹地段矿体厚度较大、品位高。本文研究成果能够指导滇东南地区残坡积物风化壳内钛矿的找矿工作。