数据与知识驱动的零件特征工艺决策方法

在零件的工艺设计阶段, 加工工艺方案的生成强依赖于设计人员选择和应用的工艺知识. 而由于实际的生产环境与设计人员选择工艺知识存在着诸多偏差, 加工方案与实际的工艺过程不匹配成为当前零件制造领域关注的难题. 为解决上述问题, 本文提出了一种数据与知识双驱动的零件特征工艺决策方法. 本方法使用基于注意力机制的MLP深度学习算法, 从结构化工艺数据中挖掘工艺知识, 关联零件特征与特征工艺标签. 将其经过数据加工后, 用于训练神经网络模型. 经过验证, 该方法能够以零件特征的工艺数据为输入, 输出其对应的特征工艺标签的概率分布, 为零件工艺方案的选择提供决策支持.     

求解弱非比例阻尼系统实模态解的阻尼矩阵摄动法

提出了一种求解弱非比例阻尼振动系统实模态解的摄动方法和将非比拟阻尼矩阵分解为比例阻尼矩阵和余项阻尼矩阵的方法.对于弱非比例阻尼振动系统,通过同时对阻尼矩阵和响应矢量进行小参数摄动,将原非比例阻尼系统分解为一系列的比例阻尼振动系统,在此基础上用正则模态变换将各阶比例阻尼的摄动方程解耦,从而求得原非比例阻尼振动系统的近似解析解.计算实例表明,此方法的结果与数值计算结果十分吻合.     

Glioblastoma Extracellular Vesicle-Specific Peptides Inhibit EV-Induced Neuronal Cytotoxicity

WHO Grade 4 IDH-wild type astrocytoma (GBM) is the deadliest brain tumor with a poor prognosis. Meningioma (MMA) is a more common “benign” central nervous system tumor but with significant recurrence rates. There is an urgent need for brain tumor biomarkers for early diagnosis and effective treatment options. Extracellular vesicles (EVs) are tiny membrane-enclosed vesicles that play essential functions in cell-to-cell communications among tumor cells. We aimed to identify epitopes of brain tumor EVs by phage peptide libraries. EVs from GBM plasma, MMA plasma, or brain tumor cell lines were used to screen phage-displayed random peptide libraries to identify high-affinity peptides. We purified EVs from three GBM plasma pools (23 patients), one MMA pool (10 patients), and four brain tumor cell lines. We identified a total of 21 high-affinity phage peptides (12 unique) specific to brain tumor EVs. The peptides shared high sequence homologies among those selected by the same EVs. Dose–response ELISA demonstrated that phage peptides were specific to brain tumor EVs compared to controls. Peptide affinity purification identified unique brain tumor EV subpopulations. Significantly, GBM EV peptides inhibit brain tumor EV-induced complement-dependent cytotoxicity (necrosis) in neurons. We conclude that phage display technology could identify specific peptides to isolate and characterize tumor EVs.     

低临界胶束浓度PEGMA-b-PCL的制备及其 药物缓释性能

以ε-己内酯（ε-CL）为疏水链段,聚乙二醇甲醚甲基丙烯酸酯（PEGMA）为亲水链段,4-氰基-4-[(十二烷基硫基硫羰基)硫基]戊酸（CDPA）为可逆加成-断裂链转移（RAFT）试剂,在以甲苯为溶剂、N2氛围、80 ℃、反应24 h的条件下,通过RAFT聚合法制备了两嵌段聚合物PEGMA-b-PCL。将其自组装为胶束用作纳米药物载体,并以姜黄素（Cur）为胶束负载药物。考察了两嵌段聚合物结构、分子量及分布,表征了胶束载体粒径、形貌,测试了胶束载体的载药和释药性能。结果表明,不同嵌段聚合物相对分子质量范围为478~7318,此类聚合物具有较低的临界胶束浓度（CMC）,在常规条件下（pH=7.4）其范围为0.920~1.600 μg/mL。胶束载体粒径范围为:68.34~186.30 nm。当n(CDPA)∶n(ε-CL)=1∶200时,胶束载药量和包封率最高,可达12.05%和75.26%。在不同pH值环境下,药物缓释性能可达15 d,其中pH=5.0时释药量可达35.38%。     

Pivotal Role of Phytohormones and Their Responsive Genes in Plant Growth and Their Signaling and Transduction Pathway under Salt Stress in Cotton

The presence of phyto-hormones in plants at relatively low concentrations plays an indispensable role in regulating crop growth and yield. Salt stress is one of the major abiotic stresses limiting cotton production. It has been reported that exogenous phyto-hormones are involved in various plant defense systems against salt stress. Recently, different studies revealed the pivotal performance of hormones in regulating cotton growth and yield. However, a comprehensive understanding of these exogenous hormones, which regulate cotton growth and yield under salt stress, is lacking. In this review, we focused on new advances in elucidating the roles of exogenous hormones (gibberellin (GA) and salicylic acid (SA)) and their signaling and transduction pathways and the cross-talk between GA and SA in regulating crop growth and development under salt stress. In this review, we not only focused on the role of phyto-hormones but also identified the roles of GA and SA responsive genes to salt stress. Our aim is to provide a comprehensive review of the performance of GA and SA and their responsive genes under salt stress, assisting in the further elucidation of the mechanism that plant hormones use to regulate growth and yield under salt stress.     

Biomimetic Modification of Water-Borne Polymer Coating with Carnauba Wax for Controlled Release of Urea

Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.     

基于模糊异质扩散的图像去噪方法

将模糊思想与Perona-Malik方法相结合,提出一种新的基于模糊理论的图像异质扩散滤波方法。把异质扩散方程中的边界停止函数看作像素梯度对于图像连续平滑区域的模糊隶属度函数,利用模糊熵的概念来确定图像中分片连续区域间的边界阈值σ。本文的模糊方法和其他经典方法的异质扩散比较实验说明,该方法在保持图像的细节方面更具有优越性。     

一种基于参考扫描的MRI相位伪影校正方法

基于参考扫描原理提出了一种MRI（Magnetic resonance imaging）相位伪影]1影的软件校正方法,首先进行一次不加频率编码梯度和相位编码梯度的参考扫描,将获得的回波链数据沿频率编码方向做傅里叶变换后求出各回波间的相位误差,由此建立相位误差补偿矩阵,对K空间数据进行校正,最后重建得到伪影校正后的图像。实验结果证明,该方法能有效消除MRI图像中的相位伪影,明显提高图像质量。     

基于冲激雷达的运动体目标检测算法

针对冲激雷达脱靶量测量中的检测问题,提出了一种新的时域多门限信号检测算法。根据冲激雷达的特点,首先采用距离门等效采样方法对运动体目标回波采样,并在此基础上,利用多门限对各距离门采样信号进行散射点回波的检测,进而通过各散射点回波平均功率的求取实现对各散射点回波的识别,从而解决了后续数据处理中信号检测精度过低和散射点无法识别的问题。仿真结果表明该算法可得到满意的检测结果。