Tuning the Electronic Structure of Graphene through Collective Electrostatic Effects

Electrostatically designing materials opens a new avenue for realizing systems with user‐defined electronic properties. Here, an approach is presented for efficiently patterning the electronic structure of layered systems such as graphene by means of collective electrostatic effects. Using density‐functional theory simulations, it is found that lines of polar elements can strongly modify the energy landscape of this prototypical 2D material. This results in a confinement of electronic states in specific regions of the sample and, consequently, in a local energetic shift of the density of states. The latter is also directly reflected in the details of the band structure of the electrostatically patterned sample. Finally, it is shown that the approach can also be successfully applied to other 2D materials such as hexagonal boron nitride, where the effects are predicted to be even more pronounced than in graphene.     

基于改进的YOLOv5网络的异常行为检测算法研究

各行各业安全问题尤为重要,对人员的异常行为须及时检测并采取相应的措施才能有效预防安全事故的发生。因此本文提出基于改进的YOLOv5网络的异常行为识别算法,通过实时处理视频监控中人员的异常行为,从而保证企业的安全运行。首先,对输入数据集进行特征提取处理,本文使用YOLOv5的backbone特征提取网络提取视频特征,能够在不同图像细粒度上聚合并形成图像特征;其次,送入到时间注意块,因为不同时刻特征的贡献值并不相同,因此加入此模块赋予特征不同的贡献值;最后,送入特征预测网络,该网络由LSTM搭建,对历史特征序列进行解码,以预测当前的特征。以玩手机和吸烟为例对所提出的网络进行验证,训练集准确率高达96.42%,测试集准确率高达95.21%。     

焙烧钼精矿块新生产线压制工艺参数优化与研究

焙烧钼精矿块的生产较钼铁具有辅料消耗少、节能、环保以及生产成本低的独特优势，随着焙烧钼精矿块炼钢技术的日趋完善和进步，国内使用钼铁炼钢将随之减少，利用焙烧钼精矿块用于炼钢其前景广阔。本文通过焙烧钼精矿块新生产线对添加剂浓度／用量、干燥时间、物料粒度选择等不同参数试验，从而确定了焙烧钼精矿块新生产线压制最佳工艺参数，同时提高了焙烧钼精矿块成球率和产品质量，深受国内外用户青睐，经济效益明显。     

Finite element method analysis of Fokker–Plank equation in stationary and evolutionary versions

The problems that often arise in stochastic dynamics can be investigated using the Fokker–Planck (FP) equation. The response of a such systems being subjected to additive and/or multiplicative random noise is represented by probability density function (PDF) that gives the full information about a response random character. Various analytic and semi-analytic solution methods have been developed for various systems to obtain results requested. However numerical approaches offer a powerful alternative. In particular the Finite Element Method (FEM) seems to be very effective. A couple of single dynamic linear/non-linear (Duffing and Van Der Pol type) systems under additive and multiplicative random excitations are discussed using FEM as a solution tool of the FP equation. The resulting PDFs are analyzed and if the analytic results exist mutually compared.     

Dewetting and microphase separation in symmetric polystyrene‐block‐polyisoprene diblock copolymer ultrathin films

The kinetics of surface structure evolution in ultrathin films of low‐molecular‐weight polystyrene‐block‐polyisoprene (M_w: 7300 g mol^?1–7300 g mol^?1) diblock copolymer at temperatures below the bulk order‐to‐disorder transition temperature are presented. Films with two different thicknesses were studied as a function of annealing temperature using atomic force microscopy. These film thicknesses enabled the investigation of the competition between microphase separation and dewetting that resulted in two different morphologies: long‐range bicontinuous structures and random holes. Three distinctive stages of structure evolution were observed in bicontinuous structure, with the underlying mechanism compared with spinodal dewetting. Thicker films presented holes on their surfaces upon annealing at elevated temperatures, and kinetics of formation of the holes were discussed. We found that the molecular mobility determined the rates of dewetting, while the microphase separation hardly affected the dewetting process. © 2015 Society of Chemical Industry     

介入医疗用中空纤维成型球囊的结构与性能

球囊导管是用于介入医疗的新型医疗器械之一,其性能决定了整个介入医疗器械的操作性能。研究了原材料、中空纤维和球囊的凝聚态结构和性能,包括元素组成、化学结构、热性能和微观结构形貌。研究表明:中空纤维成型球囊导管的内部微观结构对力学性能影响显著,球囊导管的结构与性能可通过加工工艺来调控。     

Repellency and some biological effects of different ultrasonic waves on Mediterranean flour moth,Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae)

Ephestia kuhniella is one of the most important stored pests in the world. Repellency and biological effects of various ultrasonic signals with different frequencies and wave shapes on adult, larvae and pupae of the pest were studied in laboratory conditions. Choice and non-choice tests was performed by an invented signal generator device. In choice tests, different ultrasonic frequencies, and for each frequency, four different waveforms were emitted by the device and numbers of repelled moths were separately calculated. Dispersion patterns, weight and survival of the pest treated by the ultrasound were compared with control in non-choice tests. The choice tests indicated that shape and frequency of ultrasound significantly affected evasive behavior of the moths by the waves. The highest repellency effects of ultrasound were observed at frequencies of 43–45 kHz and wave shapes of Sin (x) and Cos (x). Male moths significantly were more affected by the ultrasound. In non-choice test, weights of the pest larvae and pupae and the larvae survival were significantly reduced when they treated by ultrasound with frequency 40–45 kHz and Sin (x) wave shape that emitted by specific pattern. Also, our findings showed that the larvae and adults considerably tend to avoid from the ultrasound source. Results of the study can be applied for control of the pest in store locations or silage.     

延川南煤层气污水回收利用工艺技术探讨

延川南区块由于自然条件限制,煤层气排采出的污水无法排放和生产用水供应紧张的矛盾较为突出。为解决此种矛盾,通过查看国内市场中污水储存、回收利用的设备材料,对煤层气排采污水回收、处理、利用技术进行研究和技术储备,拟选取一体化系统设备对延川南煤层气污水进行处理回收。