Analysis and optimization of high-power pulse transformer for SXFEL

Longitudinal injection is a promising on-axis injection scheme for diffraction-limited storage rings. In the latest version of the Hefei advanced light source(HALS), both the dynamic aperture and momentum aperture have been optimized. A longitudinal injection scheme was investigated on the HALS using a doublefrequency radio frequency system. To evaluate the injection performance, various errors were considered. A series of tracking simulations were conducted, and the injection efficiency was obtained under different error levels.     

Studies of Conformational Changes of Tubulin Induced by Interaction with Kinesin Using Atomistic Molecular Dynamics Simulations

The transition between strong and weak interactions of the kinesin head with the microtubule, which is regulated by the change of the nucleotide state of the head, is indispensable for the processive motion of the kinesin molecular motor on the microtubule. Here, using all-atom molecular dynamics simulations, the interactions between the kinesin head and tubulin are studied on the basis of the available high-resolution structural data. We found that the strong interaction can induce rapid large conformational changes of the tubulin, whereas the weak interaction cannot. Furthermore, we found that the large conformational changes of the tubulin have a significant effect on the interaction of the tubulin with the head in the weak-microtubule-binding ADP state. The calculated binding energy of the ADP-bound head to the tubulin with the large conformational changes is only about half that of the tubulin without the conformational changes.     

液态羊乳的加工研究进展

进入营养健康时代,消费需求不断升级,功能、营养、个性化的产品越来越受到重视.羊乳一直是人类营养的重要组成部分,与牛乳相比,羊乳的营养价值相对较高,凝乳的形成更柔软,乳脂肪小球的比例更高,致敏性低,与人乳更接近,是许多重要营养素的良好膳食来源.除了羊乳的许多有益作用外,饲养山羊和绵羊的优势,如动物成本较低、对饲料和水的需...     

提高深度剖析拉曼光谱的纵向分辨能力

使用适当似从理论上给出了共焦显微拉曼光谱仪的纵向仪器响应函数，针对相对薄（几个μm)的样品（诸如半导体薄膜材料）给出了一个简化的卷积模型，利用共焦显微拉曼光谱的深度剖析方法，研究了激光晶化后的非晶硅薄膜，并利用反卷积算法，提高了对薄膜纵向结构的分辨能力，发现了激光晶化产生的纳米微晶硅仅位于薄膜中间。     

稀释器采用流量比标定方法的不确定度分析

分析了稀释器的不同标定方法和由其产生的稀释比偏差,得出采用流量比标定稀释器的方法较好,同时建议采用粒子计数器计算稀释器上下游的粒子浓度比,以评估标定稀释器时两种稀释比测量结果的允许误差。     

基于洛伦兹变换和PageRank算法的数据资产估值

数据资源是组成数字社会的重要生产资料, 数据资源价值的评估是数据交易、数据流通和数据升值变现的重要基础. 以洛伦兹变换和PageRank算法为理论基础依据, 首先利用PageRank算法计算其在数据资产参价体系中的权重系数, 进而得到数据资产初始估值. 然后再利用质速关系映射的数据资产估值模型对给定的数据资产进行估值. 实验结果表明, 提出的数据资产估值方法, 具有一定的高效性和市场参照效用.     

目标检测数据集半自动生成技术研究

目标检测广泛使用于计算机视觉领域.在不同的场景中,我们需要使用不同的数据集训练模型.但是,人工生成数据集标签非常耗时.本文提出一种半自动的方法生成数据集标签,然后按照图像相似度设置的阈值自动筛选,最后保留符合要求的图像和对应的标签作为最终的数据集.实验表明,该方法可以提高数据集生成标签的速度,同时确保了准确率.     

基于田口方法的微波组件金丝键合工艺优化

为了提高微波组件金丝键合的可靠性,采用楔形金丝键合工艺进行了金丝互连,通过田口试验方法设计 和试验验证,确定了金丝键合最优化的工艺参数组合。研究结果表明：键合金丝质量的影响因素依次是超声功率、键 合压力和键合时间,优化的工艺参数组合依次为超声功率、键合压力、键合时间,优化的工艺参数组合为超声功率 15、键合压力16、键合时间50;采用优化后的工艺参数进行金丝键合操作,获得了稳定性良好的互连金丝,完全满 足混合集成微波电路金丝键合互连应用的需求。     

Experimental investigation of propagation mechanisms and fracture morphology for coalbed methane reservoirs

Fracture propagation mechanisms in coalbed methane (CBM) reservoirs are very complex due to the development of the internal cleat system. In this paper, the characteristics of initiation and propagation of hydraulic fractures in coal specimens at different angles between the face cleat and the maximum horizontal principal stress were investigated with hydraulic fracturing tests. The results indicate that the interactions between the hydraulic fractures and the cleat system have a major effect on fracture networks. “Step-like” fractures were formed in most experiments due to the existence of discontinuous butt cleats. The hydraulic fractures were more likely to divert or propagate along the butt cleat with an increase in the angles and a decrease in the horizontal principal stress difference. An increase in the injection rate and a decrease in the fracturing fluid viscosity were more conducive to fracture networks. In addition, the influence on fracture propagation of the residual coal fines in the wellbore was also studied. The existence of coal fines was an obstacle in fracturing, and no effective connection can be formed between fractures. The experimental investigation revealed the fracture propagation mechanisms and can provide guidance for hydraulic fracturing design of CBM reservoirs.     

k-近邻关系下的空间高效用核模式挖掘

空间数据挖掘旨在从空间数据库中发现和提取有价值的潜在知识.空间co-location(共存)模式挖掘一直以来都是空间数据挖掘领域的重要研究方向之一,其目的 是发现一组频繁邻近出现的空间特征子集,而空间高效用co-location模式挖掘则考虑了特征的效用属性.二者在度量空间实例的邻近关系时一般都需要预先给定一个距离阈值...