深度神经网络模型后门植入与检测技术研究综述

作为当前人工智能快速发展的代表性技术之一,深度神经网络的应用范围越来越广,由此带来的安全性问题也逐渐受到关注。现有研究主要聚焦于如何高效构造多样化的对抗样本,以实现对深度神经网络模型的欺骗,以及如何检测对抗样本并加固深度神经网络模型。但是,随着深度神经网络模型的开发越来越依赖开源数据集、预训练模型和计算框架等第三方资源,模型被植入后门的风险越来越高。从深度神经网络模型生命周期的各个环节出发,对深度神经网络模型后门植入与检测相关技术进行了归纳总结,对比分析了不同技术的主要特征与适用场景,对相关技术未来的发展方向进行了展望。     

新型芳香二胺的合成及其聚酰亚胺的应用研究

首先通过双酚A和碳酸钾反应得到酚钾盐,与间-二硝基苯反应合成2,2-双[4-(3-硝基苯氧基)苯基]丙烷(3-BNPP),再用水合肼还原得到新型芳香二胺单体2,2-双[4-(3-氨基苯氧基)苯基]丙烷(3-BAPP)。用3-BAPP与多种二酐合成出多种聚酰亚胺,并在二层法挠性覆铜板(2L-FCCL)的应用方面做了一些研究。研究表明其相应的2L-FCCL具有良好的耐锡焊性能和较低的吸水率。     

向量测量技术在安规测量中的应用

本文根据交流耐压测试的实际需求提出了向量测量的概念,其中介绍的测量真实电流的基本原理和电路对当前提高耐压测量仪器的设计水平具有非常实际的意义。     

双导柱大吨位升降机设计及应用

介绍了双导柱大吨位升降机主要优点和参数,并对其结构进行分析,详细说明了双导柱大吨位升降机工作原理、对重系统、驱动机构、安全装置、电气控制系统,并给出了工程应用实例。     

塔式起重机基础在深基坑中的设置

介绍深基坑工程内塔式起重机基础的设置,通过钢格柱逆作法施工的应用,将塔式起重机安装在深基坑内,并提出了施工要点和注意事项,有效地控制了塔式起重机设置施工的成本,并确保了工程的施工进度。     

Characterization of a Thermostable and Surfactant-Tolerant Chondroitinase B from a Marine Bacterium Microbulbifer sp. ALW1

Chondroitinase plays an important role in structural and functional studies of chondroitin sulfate (CS). In this study, a new member of chondroitinase B of PL6 family, namely ChSase B6, was cloned from marine bacterium Microbulbifer sp. ALW1 and subjected to enzymatic and structural characterization. The recombinant ChSase B6 showed optimum activity at 40 °C and pH 8.0, with enzyme kinetic parameters of K_m and V_max against chondroitin sulfate B (CSB) to be 7.85 µg/mL and 1.21 U/mg, respectively. ChSase B6 demonstrated thermostability under 60 °C for 2 h with about 50% residual activity and good pH stability under 4.0–10.0 for 1 h with above 60% residual activity. In addition, ChSase B6 displayed excellent stability against the surfactants including Tween-20, Tween-80, Trion X-100, and CTAB. The degradation products of ChSase B6-treated CSB exhibited improved antioxidant ability as a hydroxyl radical scavenger. Structural analysis and site-directed mutagenesis suggested that the conserved residues Lys248 and Arg269 were important for the activity of ChSase B6. Characterization, structure, and molecular dynamics simulation of ChSase B6 provided a guide for further tailoring for its industrial application for chondroitin sulfate bioresource development.     

TaNBR1, a Novel Wheat NBR1-like Domain Gene Negatively Regulates Drought Stress Tolerance in Transgenic Arabidopsis

Drought stress is an important factor that severely affects crop yield and quality. Autophagy has a crucial role in the responses to abiotic stresses. In this study, we explore TaNBR1 in response to drought stress. Expression of the TaNBR1 gene was strongly induced by NaCl, PEG, and abscisic acid treatments. The TaNBR1 protein is localized in the Golgi apparatus and autophagosome. Transgenic Arabidopsis plants overexpressing TaNBR1 exhibited reduced drought tolerance. When subjected to drought stress, compared to the wild-type (WT) lines, the transgenic overexpressing TaNBR1 plants had a lower seed germination rate, relative water content, proline content, and reduced accumulation of antioxidant enzymes, i.e., superoxide dismutase, peroxidase, and catalase, as well as higher chlorophyll losses, malondialdehyde contents, and water loss. The transgenic plants overexpressing TaNBR1 produced much shorter roots in response to mannitol stress, in comparison to the WT plants, and they exhibited greater sensitivity to abscisic acid treatment. The expression levels of the genes related to stress in the transgenic plants were affected in response to drought stress. Our results indicate that TaNBR1 negatively regulates drought stress responses by affecting the expression of stress-related genes in Arabidopsis.     

网络外部性下E-商务平台IT投资决策仿真研究

在Netlogo仿真软件基础上,基于双寡头电子商务平台序贯投资决策博弈模型,设计包含电子商务平台市场环境、事件和主体的仿真系统,调整相关环境变量和各类主体属性参数,观察竞争平台的价格、收益等变化。仿真研究结果发现,先后进入市场的双寡头平台竞争优势由技术进步水平和转移成本的相对大小所决定,当技术进步水平较高时后进入平台具有后动质量优势,反之,先进入平台能够通过构建进入壁垒锁定用户而获得先动优势,网络外部性的存在会扩大竞争差距。但后进入平台和先进入平台完全兼容时,则可以通过更高质量的服务扩大市场份额,在竞争中的优势地位。     

记忆合金在弹箭引信安全系统中的应用研究

研究利用Ti—Ni记忆合金的记忆效应，设计制作了引信安保机构原理样机，并对样机进行了解除保险可靠性试验、勤务处理安全性试验和气体炮试验。经一系列试验研究证明，记忆合金在弹箭引信安全系统中做保险件，具有保险、延期解除保险和驱动负载的综合能力。为引信多样化的安全设计提供了一种新的途径。     

行波杆在混凝土应力波参数测量中的应用

根据一维弹性波理论,提出了一种应用行波杆对混凝土内应力波参数进行测量的方法,介绍了该方法的测量原理,设计了该方法中行波杆的长度、外径和材质等关键参数,并构建了在爆炸载荷驱动下的混凝土实验模型,配置了测试系统。实验结果表明,行波杆设计方法正确,各项参数符合测试需求,实验数据真实可靠。