矿业金属探测器的设计

针对金属探测器容易产生误报和漏报的问题,对金属探测器进行改进和研究。根据金属和矿石导磁性的不同,以感应电动势作为金属探测器研究的基础;以DSP作为控制核心,并设有多重滤波器、放大器、速度传感器、人机界面和输出继电器。实验表明,检测精度最小为直径1.5 cm长为4 cm的铁棍。     

Recent advances in the solution self‐assembly of amphiphilic “rod‐coil” copolymers

Solution self‐assembly of amphiphilic “rod‐coil” copolymers, especially linear block copolymers and graft copolymers (also referred to as polymer brushes), has attracted considerable interest, as replacing one of the blocks of a coil‐coil copolymer with a rigid segment results in distinct self‐assembly features compared with those of the coil‐coil copolymer. The unique interplay between microphase separation of the rod and coil blocks with great geometric disparities can lead to the formation of unusual morphologies that are distinctly different from those known for coil‐coil copolymers. This review presents the recent achievements in the controlled self‐assembly of rod‐coil linear block copolymers and graft copolymers in solution, focusing on copolymer systems containing conjugated polymers, liquid crystalline polymers, polypeptides, and polyisocyanates as the rod segments. The discussions concentrate on the principle of controlling over the morphology of rod‐coil copolymer assemblies, as well as their distinctive optical and optoelectronic properties or biocompatibility and stimuli‐responsiveness, which afford the assemblies great potential as functional materials particularly for optical, optoelectronic and biological applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1459–1477     

高精度太阳辐照度仪的光谱扫描测量

为了实现对太阳辐射的绝对测量和大气特性的精确反演,研制了光谱覆盖范围在0.4~1.0μm的高精度太阳光谱辐照度仪。太阳辐照度仪采用Fèry棱镜实现入射太阳光的色散,闭环控制光谱扫描机构的方法实现光谱扫描。论文详细介绍了太阳辐照度仪光谱扫描测量部分的设计。给出了Fèry棱镜的设计要求,实现单一元件完成光谱色散;利用陷阱探测器进行光谱采集,保证了测量精度;结合探测器的性能参数,说明了温控的需求和方法;介绍了光谱扫描结构的设计方法,实现了精确的波长定位;给出了音圈电机的参数、稳定性和供电要求,实现了0.025%的波长定位误差。开展室外观测实验,实现了0.4~1.0μm波段的太阳细分光谱扫描测量,并分别与可见-短波红外光谱仪和自动太阳光度计(CE318)进行了对比。结果表明,辐照度仪的光谱扫描测量结果的吸收峰波长值吻合,与CE318全天测量数据的相对偏差小于0.13%,可见波段的光学厚度的相对偏差小于2%,近红外波段的相对偏差小于4%。     

Insights into poly(3‐hexylthiophene)‐b‐poly(ethylene oxide) block copolymer: Synthesis and solvent‐induced structure formation in thin films

We report the synthesis, characterization, and solvent‐induced structure formation in thin films of an amphiphilic rod‐coil conjugated block copolymer, poly(3‐hexylthiophene)‐b‐poly(ethylene oxide). The diblock copolymers were prepared by a facile click reaction and their characterizations as well as thermal, crystalline, optical properties, and self‐assembly behavior have been investigated in detail. A series of morphologies including two‐phase separated nanostructure, nanofibrils, and their mixed morphology could be obtained depending on the selectivity of solvents to different blocks. Structural analyses demonstrate there is a subtle balance between microphase separation of copolymer and the π‐π stacking of the conjugated P3HT and such balance can be controlled by changing the solvents of different selectivity in solution and the length of P3HT block. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Experimental and Numerical Investigation of Coil Heating in Hydrogen Annealing Furnace for Optimum Arrangement of Charge

Annealing furnace heat transfer mechanisms were investigated both experimentally and numerically to determine optimum stacking arrangements of coils in one charge. Heating order of the coils in one charge was first determined from experimental conditions in order to interpret temperature differences between coils. A mathematical model and annealing furnace heat transfer relations were used to predict the thermal behavior of coils during the heating process. When the accuracy of the model had been ensured, the heating of the coils was simulated with different stacking arrangements and the best arrangement with the shortest heating time possible was determined. A saving of 1 to 5% was observed in the burning time of furnaces for certain stack arrangements.     

A Novel Nanocage from the Cooperative Self‐Assembly of Coil–Rod–Coil Triblock Copolymers and Nanopartilces

A Dissipative particle dynamics (DPD) simulations are performed to study the cooperative self‐assembly of coil–rod–coil triblock copolymers and nanoparticles in solution. The results show that, when the nanoparticle concentration exceeds a given value, the ternary systems can form a novel nanocage composed of two‐end coil‐caps and middle rod‐linkers. The novel nanocage is very similar to the real bird cage and the captured nanoparticles like the bird. It is the first nanocage from the self‐assembly of coil–rod–coil triblock copolymers. This may be used for the release of drugs and fertilizers, or as nanoreactors.

     

音圈电机推力迟滞特性研究

为实现音圈电机推力的精确控制,基于Preisach模型对音圈电机的推力迟滞特性进行了建模,构建了音圈电机的推力迟滞逆模型,并设计了开环逆补偿器,对有逆补偿器和无逆补偿器的音圈电机进行了推力特性试验.结果表明,有逆补偿器的音圈电机推力迟滞环明显小于无逆补偿器的音圈电机.且有逆补偿器的音圈电机推力最大绝对误差为0.2 N,相对误差基本维持在3%以内.无逆补偿器的音圈电机推力最大绝对误差达到了0.75 N,相对误差变化较大,补偿后推力绝对误差最大降低了73%.      

气垫导轨上的电磁感应实验

利用滑块带动金属杆切割亥姆霍兹线圈中心区域匀强磁场的磁感应线,可以产生感应电动势.通过实验可以验证感应电动势大小与金属杆运动速度、长度以及磁感应强度之间的关系,也可以验证感应电动势大小和磁通量变化率成正比.     

Energy non-collapsing and refined blowup for a semilinear heat equation

Refined structures of blowup for non-collapsing maximal solution to a semilinear parabolic equation

$u_t?△u=|u{|}^{p?1}u$

with $p>1$ are studied. We will prove that the blowup set is empty for non-collapsing blowing-up in subcritical case, and all finite time non-collapsing blowing-up must be refined type II in critical case. When $p>p_S\equiv \frac{N+2}{N?2}$ for $N\ge 3$, the Hausdorff dimension of the blowup set for maximal solution whose energy is non-collapsing is shown to be no greater than $N?2?\frac{4}{p?1}$, which answers a question proposed in [7] positively. At the end of this paper, we also present some new examples of collapsing and non-collapsing blowups.     

均匀带电正方形线圈的空间电场分布

利用教材中一个常见例题的结论,将带电正方形线圈视为四段带电直棒,采取分段计算然后利用场的叠加原理,导出带电正方形线圈空间电场分布的普遍表达式,并讨论线圈平面上的电场分布情况。