基于形态特征提取的急性下壁心肌梗死BiLSTM网络辅助诊断算法

急性下壁心肌梗死是一种病发急、进展快、致死率高的心脏疾病,该文提出一种新颖的基于形态特征提取的BiLSTM神经网络分类的急性下壁心肌梗死辅助诊断算法,可大幅度提高医生对急性下壁心肌梗死疾病的诊断效率并有助于及时确诊.算法包括:对胸痛中心数据库心拍信号进行降噪及心拍分割;根据临床心内科医学诊断指南提取了12导联波形距离特征和分导联波形幅值特征;依据提取的特征搭建LSTM与BiLSTM神经网络进行心拍的分类识别;使用PTB公开数据库和胸痛中心数据库多临床中心进行交叉验证.实验结果表明,加入胸痛中心真实临床数据后,基于形态特征提取BiLSTM神经网络的急性下壁心肌梗死辅助诊断算法准确率达到99.72％,精度达到99.53％,灵敏度达到100.00％,同时F1-Score达到99.76.该算法比其他现有算法准确率提高至少1％,该项研究具有非常重要的临床应用价值.     

Microstructure and coloring mechanism of iron spots on bluish white porcelain from Jingdezhen of the Song Dynasty

Jingdezhen is famous for its bluish white (Qingbai) porcelains of the Song Dynasty, and those decorated with iron spots are distinctive among them. Herein, iron spots on a bluish white porcelain were investigated using a series of microscopic and spectroscopic characterizations. We found the decreasing iron content from more than 8 wt% to about 2 wt% during the glaze color transition from rusty to brown and finally into green, which built a connection on the coloring mechanism of iron-rich crystallized glaze and celadon glaze. We identified the rare ε-Fe₂O₃, a promising magnetic material, in both the dark brown crystals and the triangular crystals in the rusty area, which is its first discovery among bluish white porcelains. Based on these findings, we discussed the coloring mechanism of iron-spot decoration along with the physical form of the iron oxide crystals, indicating the partially reducing atmosphere during firing process.     

Fabrication of hierarchical PANI@W-type barium hexaferrite composites for highly efficient microwave absorption

Hexagonal barium ferries is a promising and efficient microwave (MW) absorbing material, but the low dielectric loss and poor conductivity have limited their extensive applications. In this work, a simple tactic of coating conductive polymer PANI on hexaferrite BaCo₂Fe₁₆O₂₇ is presented, wherein the dielectric properties are customized, and more significantly, the electromagnetic loss is greatly enhanced. As displayed from structural characterizations, PANI were coated equably on the surface of hexaferrite grains by an in-situ polymerization process. The outcomes exhibit the as-prepared PANI@hexaferrite composite has remarkable electromagnetic wave absorption capacity. When the thickness is 6.0 mm, the minimal RL of ?40.4 dB was achieved at 2.9 GHz. The effective absorption bandwidth (RL < ?20 dB) of 0.65 GHz, 0.53 GHz, 0.65 GHz, 0.52 GHz, 0.46 GHz and 0.39 GHz was achieved separately when the thickness ranges from 4 to 9 mm. The highly efficient MW absorbing performance of PANI@hexaferrite composite were the consequence of multiple loss mechanisms and perfect impedance matching. It is demonstrated that the PANI@hexaferrite composite with excellent MW absorption performance is expected to be potential MW absorbers for extensive applications.     

一种基于Spark的不确定数据集频繁模式挖掘算法

如何在海量不确定数据集中提高频繁模式挖掘性能是目前研究的热点.传统算法大多是以期望、概率或者权重等单一指标为数据项集支持度，在大数据背景下，同时考虑概率和权重支持度的算法难以兼顾其执行效率.为此，本文提出一种基于Spark的不确定数据集频繁模式挖掘算法（UWEFP），首先，为了同时兼顾数据项的概率和权重，计算一项集的最大概率权重值并进行剪枝；然后，为了减少对数据集的多次扫描，结合Spark框架的优点，设计了一种具有FP-tree特征的新颖的UWEFP-tree结构进行模式树的构建及挖掘；最后在Spark环境下，以UCI数据集进行实验验证.实验结果表明本文的方法在保证挖掘结果的同时，提高了效率.     

切削液的正确设计及其质量评估

随着机械加工向高速、强力、精密等方向迅速发展，对切削液也提出了越来越高的要求。正确设计切削液，并采用恰当的方法对其质量进行有效的评估，可以使切削速度提高，减小切削力，以达到提高生产率、加工质量、减少切削时间、延长刀具的使用寿命和降低生产成本之目的。     

A Special Structure in Al-Mg-Li Alloy (01420) Weld Metal

A large quantity of laminated fine grain zones were observed in the Al-Mg-Li alloy weld metal by manual TIG, which was not found in ordinary Al alloy welds. The fine grain zone is formed because of the Al3(Zr,Ti) particles in the filler metal and the manual filling of filler metal in welding process     

半固态ZnAl 27合金及其二次加热组织

研究了半固态ZnAl27合金及其二次加热组织。结果表明，半固态ZnAl27合金基本无宏观偏析，其组织为细小均匀的近球形非枝晶，综合力学性能远远高于常规铸造合金；二次加热后，α相进一步球化，边缘变得光滑圆整，可以满足半固态触变成形的需要。     

Merging Functional Form Feature into GT Codes to Enhance the CAD/CAM Integration

The TangShan Research Institute of Group Technology has been engaged in the develop-ment of GT for the light industry machinery building factories since 1980.Under its overall supervisionmore than 8 factories have applied GT to drawing control and process planning,while 4 of them reorga-nized their machine shops into GT cells and the throughput capabilities were raisd immediately by 15 toeven 49%.Since the existing GT coding systems predict only the global characteristics of machine parts,theirapplication alone is unable to transfer all the information needed for the CAD/CAM integration in aCIM environment.From the very beginning of 1989,we started to study the feasibility of introducingconcepts of Functional Form Features into GT codes.Based on the exhaustive study of nearly 100,000part drawings from machineries for making pottery and porcelain appliances,cigarette,paper pulp,glass bottles,plastics moulding,beer and beverage filling etc.,a new GT/FFF coding system wasworked out and a corresponding set of standard drawings assembled from FFF primitives Was formulat-ed which can cover up to 65—75% of existing parts from light industry machineries.FFF based GTcodes greatly facilitate the standardization control of released drawings,accelerate the engineering de-sign and process planning,and certainly will play an important role in the future CIM organization.     

我国未来移动通信研究开发展望

本文简述了国内移动通信的发展现状与趋势，重点论述了国际上有关Beyond 3G移动通信发展动向，提出了我国发展未来移动通信的基本技术需求，概述了我国有关Beyond 3G研究计划-FuTURE计划的安排与步骤。     

储层敏感性快速预测软件在大港油田的研究与应用

在储层特征分析，室内实验，机理研究的基础上，利用人工神经BP网络建立预测模型，并编制了预测储层5种敏感性的软件，该软件受人为因素干扰小，所需参数少，准确度高，综合符合率大于80％现场应用结果表明，该技术能为制定保护油气层技术措施提供较可靠的依据，能提高油田滚动开发效益，改善老油田的开发效果，该软件对BP算法进行了改进，（1）从两方面入手使网络摆脱平坦区，一是对输入数据进行归一化处理，使O1的取值在[0,1]之间，二是一旦网络陷入平坦区域，局部极小，使连接权值Wkj,Wji和阈值Qk,Qj同时缩小一个因子，λ＞1，可使Ok(1-Ok)脱离零值，离开平坦区；（2）加速收敛，方法有自动调整学习因子，添加动量项以及对权值进行批处理，用BP算法预测储层潜在敏感性，首先应确定影响储层敏感性的主要因素，然后根据这些因素有针对性地收集有关资料并进行处理，再根据敏感性预测的要求，设计相应的网络结构进行训练，最后对训练好的网络进行.检验。