自适应开环测量氡析出率的方法研究

利用开环方式测量氡析出率,不需要考虑泄漏和反扩散的影响,计算简单.但是开环方式测量氡析出率测量中有一个很重要的参数是泵的流率,对于高析出率介质,采用较高的流率,可以减小集氡罩内氡浓度达到恒定的时间,提高测量效率;对于低析出率介质,采用较高的流率,会导致集氡罩内的氡浓度值偏低,统计涨落较大,甚至会使得集氡罩内的氡浓度值难...     

基于小波包变换与自适应阈值的SMT焊点图像去噪

为提高表面组装技术焊点图像去噪效果,提出一种基于小波包变换和自适应阈值的焊点图像噪声去除新方法.利用小波包变换对图像进行多层分解,通过对图像小波包树系数的分析,对小波包树系数高频部分和低频部分进行Wiener滤波;为提高去噪性能,通过计算小波包系数对应的中值绝对方差估计,提出一种改进的自适应小波包阀值算法,并对图像进行...     

基于MSP430控制的智能声光控灯头电路设计

针对传统设计存在的缺陷,以MSP430单片机为核心。设计了一种智能声光控灯头。可通过人为设置来控制灯泡持续发亮的时间;通过调节光敏电阻和控制传声器灵敏度的滑动变阻器,能方便调节对光和声音的响应条件,从而使声光控技术更加人性化、智能化。     

Generation of four-photon GHZ states based on interaction between a four-level atom and two bimodal cavities

A simple scheme is presented for generating four-photon Greenberger-Horne-Zeilinger (GHZ) states with interaction between a four-level atom and two bimodal cavities. In the proposed protocol, the quantum information is encoded on Fock states of the cavity fields. The detection of the atom can collapse the cavity to the desired state. The experimental feasibility of our proposal is also discussed.     

合成碳羟基磷灰石对水中苯酚的吸附

利用废弃蛋壳为原料、尿素为添加剂,合成了碳羟基磷灰石(CHAP),用于吸附水中苯酚. 利用红外光谱、扫描电镜、X射线能谱测试技术对CHAP样品表面化学进行了表征,同时考察了环境pH值、吸附时间、苯酚初始浓度及温度对苯酚吸附的影响. 结果表明,在酸性(pH=3~5)和碱性(pH=9~10)条件下,CHAP对苯酚的吸附效果较好,吸附过程符合Langmuir和Freundlich等温式,同时也符合准二级动力学模型.     

A Visual Programming Language for Expressing Rhythmic Visuals

Sonnet+Imager is an object-based toolkit for creating instruments that produce abstract graphics in real-time. It is implemented as a visual programming language of the component-circuit variety. It was designed by identifying and addressing some of the principle limitations in the Max-based graphics engine, Imager. Beyond that, we wanted to address rhythm directly. This required us to make time a first-class element of the language. The model of time relies for its power on the notion of functors, an encapsulation of mathematical functions that can be related to the dimensions of rhythm. All the elements of time manifest themselves directly in the visual language, as components and data packets, thereby creating natural flows that describe rhythmic structures. The resulting design is modular, intuitive, interactive and extensible.     

橡胶硫化促进剂NS的合成研究

本研究采用促进剂M、叔丁胺为原料,以过氧化氢为氧化剂,用水做溶剂在酸性条件下合成橡胶硫化促进剂NS。并通过实验得到优化工艺条件:n(叔丁胺)/n(促进剂M)为2.0、n(过氧化氢)/n(促进剂M)为1.5、反应温度为60℃和反应时间为90min,在此工艺条件下合成橡胶硫化促进剂NS的收率可达90.0%。     

小波核支持向量机的网络入侵检测

将小波理论和统计学习运用到网络入侵检测中,使用小波核支持向量机(WSVM)对网络连接信息进行攻击检测和异常发现。仿真试验结果表明,与RBF核相比,小波核支持向量机在泛化能力和检测能力方面都有所提高。     

Ketjen black carbon supported CoO@Co−N−C nanochains as an efficient electrocatalyst for oxygen evolution

We demonstrate an extremely facile in-situ pyrolysis followed by the reduction of partial Co²⁺ route to synthesize novel Ketjen black carbon (KB) supported CoO@Co?N?C (denoted as CoO@Co?NC/KB) nanochains using KB, urea and cobalt (Ⅱ) acetate as co-precursors. The as-prepared CoO@Co-NC/KB displays higher electrocatalytic activity, smaller Tafel slope and better durability for the oxygen evolution reaction than those of the benchmark commercial RuO₂ catalyst in 1.0 M KOH solution, far outperforming the control groups (i.e. CoO@Co?g-C₃N₄/KB, Co?NC/KB, CoO?NC/KB, CoO@Co/KB, CoO@Co?NC and Co₃O₄?NC/KB). The remarkable electrocatalytic performance of CoO@Co?NC/KB is primarily credited to the synergistic effect between Co and CoO species with a core-shell structure, increased active sites and considerably enhanced electronic conductivity.     

Facile synthesis of cobalt modified 2D titanium carbide with enhanced hydrogen evolution performance in alkaline media

2D transition metal carbides, nitrides and carbonitrides, namely the MXenes, attract more and more attentions due to their unique properties. Here, we report a simple one-step molten salt etching method to prepare Co modified MXene hybrid (Ti₃C₂T_x:Co) by the reaction of Ti₃AlC₂ with Lewis acid CoCl₂ at 750 °C. Most of Co atoms aggregates in the interlayered space of Ti₃C₂T_x. Benefitting from the improved electron charge transfer efficiency and increased active sites, the sulfuric acid treated Ti₃C₂T_x:Co-12h hybrid exhibits excellent electrocatalytical activity for hydrogen evolution reaction in alkaline media, delivering a current density of 10 mA cm⁻² at an overpotential of 103.6 mV, which is lower than most noble metal free MXene based electrocatalysts. The results illustrate that the proposed method is very facile and useful to incorporate mid-to-late transition metals into the MXene phase to prepare MXene based HER electrocatalysts.