基于非外部场的感应式电导率传感器优化设计

针对目前感应式电导率传感器存在邻近效应影响导致测量不准确的问题,分析了感应式传感器产生邻近效应的机理。优化设计了一种基于非外部场的感应式电导率传感器探头及信号处理电路,进行了标定与稳定性实验。实验结果表明,非外部场传感器电导率测量准确度小于±0.05 mS/cm。在外界物质邻近电导率测量对比实验中,相较于OST36D型感应式传感器测量偏移达到-0.1 mS/cm~0.7 mS/cm,非外部场传感器的测量偏移小于±0.015 mS/cm,为海水电导率高精度测量提供了一个解决方案。

外部能场辅助搅拌摩擦焊接技术综述

外部能场辅助搅拌摩擦焊接是一种改进型固相焊接方法,在航空航天、汽车制造、能源领域等方面得到了广泛应用,通过引入外部能场,可以改善焊接接头的组织和性能,提高焊接质量和效率。本文对外部能场辅助搅拌摩擦焊接技术进行了分类,综述了能场的选择和控制、工艺参数的优化等,阐述了外部能场对焊接温度、轴向载荷、接头组织性能的影响,最后总结了外部能场辅助搅拌摩擦焊接技术未来的发展趋势。

波导缝隙外部半空间场矩阵元素的计算方法

本文证明了用Galerkin法对波导缝隙特性分析时 ,Fourier变换法导出的缝隙外部半空间场的矩阵元素公式与一般积分法导出的公式是等同的 .同时把这两种方法中含有二重积分的公式简化为一重积分形式 .

手臂屈伸运动中上位最优控制对外部速度力场的补偿适应

描述人体手臂适应外部力场的计算模型通常使用下位的前馈模块加以补偿,本研究提出当环境可以在内部模型中准确表达时,上位最优控制模块可以直接起到前馈补偿的作用。将与速度有关的力场(VF)施加到神经肌肉骨骼模型,并用最优控制方法进行仿真。仿真结果不仅与实验中手臂运动轨迹演化趋势相一致,同时与手臂末端阻抗椭圆也能很好的匹配。数值论证表明,人体可能仅通过调节上位最优控制模块中很少的参数就可以适应与补偿外部新环境。

外部环境场对超强台风“苏迪罗”(2015)快速发展的影响

文章利用NCEP提供的FNL全球格点资料等,对台风“苏迪罗”(2015)快速发展阶段的外部环境场进行分析,并运用天气学诊断的方法讨论外部环境场对“苏迪罗”快速发展的影响。结果表明:(1) 在“苏迪罗”快速发展的过程中,其附近的海表温度均在29℃以上,为“苏迪罗”提供了足够的能量。(2)在“苏迪罗”快速发展的过程中,持续时间长、强度强、范围广的西南季风为“苏迪罗”提供了充沛的水汽,强烈的水汽输送配合辐合上升对“苏迪罗”强度的增强十分有利。(3) 在“苏迪罗”快速发展的过程中,环境风垂直切变值逐渐减小,说明弱的环境风垂直切变有利于“苏迪罗”的强度增强。(4) 强烈的高空辐散与低层辐合的配置有利于加强台风的抽气作用,使“苏迪罗”的低层进一步减压,强度增强。

河北省主要城市吸引范围

依据空间相互作用理论 ,利用断裂点方法 ,根据河北省各城市的综合实力 ,确定了 1 1个省辖市各自的吸引范围 .并分析了京津对河北省城市吸引范围的影响 .

关于露天采煤技术发展问题的探讨

在大力发展我国的煤炭工业中,加强露天开采是一项重要的决策。因此,认真总结国内外的基本经验,积极地研究我国露天采煤技术的发展方向、技术特点和技术政策是非常必要的。 (一) 美国在六十年代以前,主要是开发阿伯拉契山区及中西部地区的露天煤田。这些煤田的特点是:气候条件较好,煤层埋藏浅,多数煤层构造简单,呈水平、近水平或缓倾斜,厚度一般不大,多位于山地或丘陵地,煤层往往在山坡上直接出露。这一时期开发了上千个规模不大(几万吨至几十万吨)的露天煤矿,大力发展向采空区直接捣排剥离物的无运输捣堆工艺和单斗——汽车(推土机、拖拉铲运机组)向采空区回填或沿山坡就近排弃剥离物的工艺方法,以及螺旋钻——汽车(或胶带输送机)回采薄煤层的采煤工艺。这一时期开发的露天煤田的煤层及剥离物厚度都不大,捣堆设备主要为“大勺斗、短脖子”的机械铲。

金属挡板对平行线栅有界波模拟器的影响仿真研究

利用基于有限积分法的电磁场仿真软件CST仿真和分析了金属挡板对大型平行线栅有界波模拟器内部可用测试区和外部辐射电场分布的影响。首先建立了平行线栅有界波模拟器仿真模型,并依据GJB8848证明了其合理性;而后重点分析了金属板对模拟器内部可用测试区电场分布的影响,并通过详实的数据列出了金属板位置、厚度、高度和长度等参数的具体作用效果;然后讨论了金属板对模拟器外部辐射电场的屏蔽效果;最后结合仿真结果提出金属挡板的设置应尽可能地远离模拟器,且有效反射面积越小越好,而对厚度无特别要求。

Linear and Nonlinear Optical Absorptions of a Hydrogenic Donor in a Quantum Dot Under a Magnetic Field

The linear and nonlinear optical properties of a hydrogenic donor in a disc-like parabolic quantum dot in the presence of an external magnetic field are studied. The calculations were performed within the effective mass approximation, using the matrix diagonalization method and the compact density-matrix approach. The linear and nonlinear optical absorption coefficients between the ground （L =0） and the first excited state （L = 1） have been examined based on the computed energies and wave functions. We find that the linear, nonlinear third-order, and total optical absorption coefficients are strongly affected by the confinement strength of QDs, the external magnetic field, and the incident optical intensity.

Improvement of Magnetic Field on Tribological Properties of Lubricating Oils with Zinc Butyloctyldithiophosphate

Tribological properties of 150 SN mineral oil and the oils doped with different contents of zinc butyloctyldithiophosphate(T202) under magnetic field or non-magnetic field were evaluated on a four-ball tribotester by applying an external magnetic field around the friction region. Moreover, the morphology and the tribochemical characteristics of worn surfaces were examined by a scanning electron microscope(SEM) and an X-ray photoelectron spectrometer(XPS). Then the lubrication mechanisms were discussed. The tribological test results indicated that the wear scar diameters(WSDs) of steel balls lubricated by the T202-containing lubricating oils and the friction coefficients of the corresponding oil under magnetic field were smaller than those without magnetic affection. The worn surface lubricated with the T202-formulated oils in a magnetic field was smoother than that obtained under the normal condition. Furthermore, the results of XPS analysis indicated that tribochemical films on the surfaces lubricated with T202-doped oils were mainly composed of compounds such as FeSO_4, FeS and ZnS. The atomic concentrations of oxygen, sulfur, iron, zinc and phosphorus species identified in T202 under magnetic field were higher than those without magnetic impact. It can be inferred that the improved anti-wear and friction-reducing ability of T202-doped oils was attributed to the promoted tribochemical reactions and the modification of the worn surfaces induced by magnetic field.

Controllable Amplification of Entanglement for Two Qutrits under Decoherence

Entanglement dynamics of a two-qutrit Heisenberg spin chain with the external magnetic fields and DM interaction under the intrinsic deeoherence is investigated. Depending on whether there is inhomogeneous magnetic field, the entanglement amplification, i.e. the phenomenon that the finally stable entanglement is bigger than that of the initial one, is found for one kind of initial states. The reasons for the controllable entanglement amplification are discussed.

Four-Electron Quantum Ring in a Magnetic Field

We study a quantum ring （QR） with four electrons in a perpendicular external magnetic field B by exact diagonalization. The low-lying spectra of the QR as a function orb are obtained. A phase diagram is presented indicating that the angular momentum and the spin of the ground state of the QR may jump when B and/or the radius of the QR vary, and a corresponding analysis is performed. By plotting the density functions of the QR, the ground-state configuration is found to be a regular quadrangle. Furthermore, the features of the ground-state persistent current are revealed.

Entanglement Resonance of End Spins in Different Spin Chains

The entanglement resonance in anisotropic spin-1/2 Heisenberg chains of different couplings is investigated when the nearest neighbor coupling is periodically modulated with external magnetic field. When the modulation frequency equals twice of the magnetic field, the entanglement resonance is larger than that at other modulation frequencies and decreases as the number of spins in the chain increases. When the modulation frequency equals the magnetic field, the entanglement resonance can be reduced to a quite low value by varying the coupling along z axis.

External Electric Field Dependence of Optical Absorbance in SnO_2 Nanoclusters

The optical absorbance in near UV wavelength region in SnO 2 nanoclusters in an external electric field is determined at room temperature. The absorbance spectra as applied field and the absorbance variations with the applied field are obtained.The relation between absorbance change and applied field is non-linear, and is saturated at high field region.

Non-Abelian Geometric Manipulation of a Crystal of Molecular Nanomagnet Mn_(12)

Based on the strong magnetic anisotropy along the symmetry of the crystal, we construct a U（2） non-Abelian gauge potential for the molecular nanomagnet Mn12 by varying the external magnetic field adiabatically. Moreover, the non-Abelian geometric phase and the unitary matrix operation, which are tile key steps to realize the universal holonomic quantum computing in the degenerate subspace, are also obtained by means of choosing an evolution path properly.

Entanglement of a Five-Qubit Heisenberg XX Chain in a Magnetic Field

We calculate the eigenvalues and eigenvectors of a five-qubit isotropic Heisenberg model in an external magnetic field, and give analytical results for the concurrence of two nearest-neighbor qubits. A magnetic field can eliminate degeneration and change the ground state of the system. Therefore increasing the value of the magnetic field can induce entanglement in a certain range both for the antiferromagnetic and ferromagnetic case.

Model for Influences of Magnetic Fields on Intracellular Calcium Oscillations

Based on the model of the two calcium stores developed by Goldbeter, the influence of external magnetic field on the calcium concentration has been discussed. We believe that the cell membrane is a major site of interaction for extremely-low-frequency （ELF） electromagnetic fields, and the permeability of ions can be changed with the changing electromagnetic fields. It is shown that magnetic field initiates intraeellular calcium oscillation with a threshold in flux density, and that the calcium oscillations do not occur if the density of magnetic field is below the threshold. The results of theoretical calculation are consistent with that of the experiment. The intracellular free calcium concentrations of different cells exposed to the same magnetic fields are different from each other. It is indicated that the different behaviors such as oscillation, rise and invariability of calcium concentration are associated with the sort of cells.

Investor Relations （IR） in Business Communication on the Example of Poland

This paper focuses on investor relations （IR） as an element of companies＇ communication with the external environment. It shows the place and role of IR in communication with the general market, and the stock exchange market in particular. The study is illustrated with an example of IR in Poland, a relatively new European Union （EU） member state and an emerging market. As can be seen, IR goes beyond the traditionally understood maintenance of communication with the capital market. It is also shown that the main role of IR ought to be the reduction of investment risk and enhancement of the companies＇ value, which is of particular significance in light of the current globalization of capital markets. It has been found that Polish companies, especially those listed on the Warsaw Securities Exchange （WSE）, commonly rely on IR as a means of communication with the environment. And yet, as the results of the analysis show, the quality of that communication is still far from satisfactory, despite efforts undertaken by various external entities to encourage more focus on the development of IR, or understanding of the company＇s relevant staff of its important role.