Oxygen vacancy-induced short-range ordering as a sole mechanism for enhanced magnetism of spinel ZnFe2O4 prepared via a one-step treatment

Despite being difficult to identify, extremely dilute oxygen vacancies have been widely reported to play an important role in enhancing magnetism in ZnFe₂O₄. The mechanisms underlying this enhanced magnetism have not been well understood for a long time and remain controversial because the formation of oxygen vacancy-rich ZnFe₂O₄ can be accompanied by changes in the chemical/physical characteristics, especially the composition, particle size, surface morphology and cation distribution, which can significantly affect the magnetization. An open and important question is whether and to what extent the enhanced magnetization can be attributed only to oxygen vacancies. In this study, the relationship between the magnetization and oxygen vacancies in ZnFe₂O₄ was definitively determined by using a carefully designed “shake-and-heat” treatment to prepare vacancy-rich samples while keeping the other crystal/surface parameters constant. Compared to the nearly vacancy-free paramagnetism samples, the vacancy-rich samples exhibited a higher magnetization of approximately 5 emu/g at both 300 K and 2 K. The Fe³⁺-O^2--Fe³⁺ superexchange paths broken by oxygen vacancies then resulting in the Fe³⁺-Fe³⁺ ferromagnetism configuration. Meanwhile, the oxygen vacancy is highly diluted then the ferromagnetism configuration is confined in a single super-cell, favoring a short-range magnetic ordering at room temperature. The concentration of oxygen vacancies was calculated to be 0.68% by magnetization measurement. Our results may shed a light on how oxygen vacancies affect magnetism.     

紧耦合式物理人机系统的交互研究综述

紧耦合式物理人机系统用于人体运动功能增强与重建,已广泛应用于助老助残、康复医疗和国防军事等领域.重点对紧耦合式物理人机系统的交互研究展开综述.通过功能划分,将系统分为功能替代型、功能康复型和功能增强型三个方面,并且详细介绍了每类系统的研究情况.接着从植入式传感和外置式传感两个方面阐述了人机交互接口的现状.然后分析了紧耦合式物理人机系统交互的意图识别算法.最后对未来发展进行展望和总结.     

New optical ceramics: High-entropy sesquioxide X2O3 multi-wavelength emission phosphor transparent ceramics

Highly transparent X₂O₃ sesquioxide ceramics were obtained from a solid solution of five different oxides (Lu₂O₃, Y₂O₃, Yb₂O₃, Gd₂O₃, and Dy₂O₃), mixed in an equal molar ratio according to the principle of high-entropy. The fabricated (Lu, Y, Yb, Gd, Dy)₂O₃ ceramics achieved 99.97 % of the relative density and exhibited a high degree of optical transparency with the in-line transmittance of almost 80 % in the visible wavelength range. Emissions of Gd³⁺ (⁶P_J → ⁸S_7/2 at 312 nm), Dy³⁺ (⁴F_9/2 → ⁶H_15/2 at 492 nm and ⁴F_9/2 → ⁶H_13/2 at 572 nm), and Yb³⁺ (²F_5/2 → ²F_7/2 at 1031 nm) suggested a potential application of the high-entropy ceramics as multi-wavelength emission phosphor transparent ceramics. High-entropy ceramics also exhibited lower specific heat and thermal conductivity compared to single-element sesquioxide ceramics. This work demonstrated that highly transparent oxide ceramics, with complex chemical compositions and good optical properties, could be obtained using the high-entropy principle.     

基于魅力工学的传统器物设计评价应用研究

目的 在传统器物的创新设计中,最重要的环节是了解消费者对所使用产品的不同感受与意向并转换为具体的设计要素.研究消费者心理的感性因素与传统器物设计元素之间的联系,确定设计要素,从而对产品进行创新设计,为提升传统器物附加值作出贡献.方法 以中国传统器物茶宠为例,首先对8位相关的茶宠专家进行访谈,通过魅力工学中的评价构造法整理并提取魅力因子,设计出问卷调查表;然后以访谈内容为依据,使用问卷调查法得到大众对茶宠的魅力评价,共回收84份有效问卷;最后应用数量化一类分析茶宠魅力因子影响权重.结果 得到了数量化一类统计表,选取了其中影响因素较大的魅力因子作为茶宠设计前的风格定调考量.结论 通过茶宠的研究案例证明了该理论的可行性,为未来传统器物的设计提供了更多元且新颖的设计依据.     

KSN:一种基于知识图谱和相似度网络的Web服务发现模型

服务发现旨在解决服务信息爆炸的问题,找到定位满足服务请求者需求的服务.由于服务描述信息主要由带有噪声的短文本组成,并且具有语义稀疏的特征,因此很难提取服务描述文档的隐含上下文信息,此外,传统的服务发现方法在获取服务的特征表示后,直接进行相似度计算,其使用的度量函数是不符合人类感知的.针对上述两个问题,文中提出了一种基于知识图谱和神经相似网络的服务发现框架(KSN).它使用知识图谱来连接服务描述和规格中的实体以获得丰富的外部信息,从而增强服务描述的语义信息,使用卷积神经网络(Convolutional Neural Network,CNN)提取服务的特征向量,并将其作为神经相似网络的输入,神经相似网络会学习一个相似度函数,用于计算服务和请求之间的相似度以支持服务发现过程.通过对ProgrammableWeb爬取的真实服务数据集的大量实验结果表明,就多种评估指标而言,KSN优于现有的Web服务发现方法.     

氧化铝纤维束织造过程中摩擦磨损性能研究

运用往复线性摩擦试验方法,搭配自制的摩擦试验夹具,模拟织造过程中氧化铝纤维束-筘齿的摩擦行为,研究加载力、预加张力和摩擦频率对悬空状态下氧化铝纤维束摩擦磨损性能的影响.结果表明:随着加载力的增加,氧化铝纤维束所受摩擦力及长丝断裂根数增加,摩擦系数减小;在预加张力为0.40 N时,氧化铝纤维束所受摩擦力和摩擦系数出现最小值,磨损程度也最小;在摩擦稳定阶段,摩擦频率增加,则氧化铝纤维束所受摩擦力先下降,后略有上升,当摩擦频率增加至5 Hz时,氧化铝纤维束的摩擦系数较1 Hz时增加18.7％,磨损程度也最为严重.     

Leucokinins: Multifunctional Neuropeptides and Hormones in Insects and Other Invertebrates

Leucokinins (LKs) constitute a neuropeptide family first discovered in a cockroach and later identified in numerous insects and several other invertebrates. The LK receptors are only distantly related to other known receptors. Among insects, there are many examples of species where genes encoding LKs and their receptors are absent. Furthermore, genomics has revealed that LK signaling is lacking in several of the invertebrate phyla and in vertebrates. In insects, the number and complexity of LK-expressing neurons vary, from the simple pattern in the Drosophila larva where the entire CNS has 20 neurons of 3 main types, to cockroaches with about 250 neurons of many different types. Common to all studied insects is the presence or 1–3 pairs of LK-expressing neurosecretory cells in each abdominal neuromere of the ventral nerve cord, that, at least in some insects, regulate secretion in Malpighian tubules. This review summarizes the diverse functional roles of LK signaling in insects, as well as other arthropods and mollusks. These functions include regulation of ion and water homeostasis, feeding, sleep–metabolism interactions, state-dependent memory formation, as well as modulation of gustatory sensitivity and nociception. Other functions are implied by the neuronal distribution of LK, but remain to be investigated.     

LaCr0.7Fe0.3O3-NiMn2O4 supported NTC composite ceramics with a sandwich-like structure

A novel sandwich-like structure was first proposed to adjust the electrical properties of NTC thermistors. The LaCr_0.7Fe_0.3O₃-NiMn₂O₄ supported composite ceramics with sandwich-like structure were initially fabricated via traditional solid-state reaction and uniaxial pressing methods, which allowed for the advantages of each component to be integrated into one material. X-Ray diffraction analysis indicates the ceramics mainly consisting of orthorhombic perovskite LaCr_0.7Fe_0.3O₃ and cubic spinel NiMn₂O₄ phases. SEM images manifest that the three layers adhered well to each other and exhibited high density. For electrical properties, the ρ_25°C was expanded to a wide range of 1182–110,233 Ω?cm and could be adjusted to the desired values by tuning the volume ratio of two basic layers, the B value was enhanced from 3358 K to 4167 K by NiMn₂O₄, and the thermal stability was improved by LaCr_0.7Fe_0.3O₃ with a resistance shift less than 0.55 % after annealing at 150 °C for 1500 h.     

绿色环保型微球的合成及性能评价

以改性淀粉、海藻酸钠改性SiO2为单体,采用反相乳液聚合法合成了绿色环保型微球体系.改性淀粉微球目前仅用于钻井液中,易降解,不适合用于驱油.本文介绍了改性淀粉占比、交联剂、引发剂及油水配比对合成产品的影响,对微球的耐温抗盐、热稳定及封堵性能进行了评价,结果表明:在交联剂质量分数为0.3％ ～0.5％、引发剂加量为单体质量的0.5％、油水配比为1:1、改性淀粉占比为3％时,合成的微球体系为乳白色半透明均相液体,初始粒径0.3～3μm.该微球体系在温度90℃、矿化度2.0×105 mg/L条件下膨胀性能较好,膨胀倍数>4,可在渗透率小于0.5μm2的油藏中形成有效封堵.本次合成对其性能进行了提升,增强了其在地层内的稳定性.     

Inorganic Nanoparticles Applied as Functional Therapeutics

Inorganic nanoparticles (NPs) offer significant advantages to the biomedical field owing to their large surface area, controllable structures, diverse surface chemistry, and unique optical and physical properties. Researchers worldwide have shown that inorganic NPs and the released metal ions can act as therapeutic agents in targeted tissues or to cure various diseases without acute toxicity. In this progress report, the recent developments in inorganic NPs with different compositions directly used as therapeutics are discussed. First, the recent convergence of nanotechnology and biotechnology in biomedical applications as well as the unique functions, features, and advantages of inorganic NPs in biomedical applications are summarized. Thereafter, the biological effects of inorganic compositions in NPs which include balancing the intracellular redox environment, regulating the specific cellular signaling and cellular behaviors, and apoptosis are explained. In addition, the emerging therapeutic applications of inorganic NPs in various diseases are exemplified. Finally, the perspectives and challenges for overcoming the weaknesses of inorganic NPs as therapeutics are discussed. By carefully considering and investigating the biological effects of inorganic NPs and metal ions released from NPs, more promising inorganic NPs based therapeutic agents can be developed.