做小孩儿，挺好！29款令人心动的儿童节礼物

dUGLY DOLL，Mood Duck收音机，浪漫星星吊灯,PERK PIONEER硬壳玩偶     

光谱技术在核桃检测领域的研究进展

近年来,光谱技术发展极为迅速,可利用物质对光的吸收、反射和透射等特性对物质进行定性和定量分析,是一种快速无损检测技术,被广泛应用于农产品的检测研究.核桃,作为我国栽培历史悠久的一种营养价值丰富的重要农产品,众多学者对其进行了长期而深入的研究.从品种鉴别、长势监测、品质鉴定、分选加工4个方面总结了高光谱和红外光谱技术在核桃检测领域的研究进展,并对比分析了各种光谱检测技术的优劣,提出了核桃相关检测中尚存的问题,并对核桃无损检测研究的发展前景进行了展望.     

一种深度学习的通货核桃品种分选方法

针对市场上通货核桃多品种掺杂、各类核桃相似度高而难以有效区分的问题，文中提出一种深度学习的通货核桃品种分选方法。建立包含四种主栽核桃品种外部种类信息图像数据库，并结合专业知识进行人工标签；构建嵌入BN的Inception多尺度特征融合结构，加速实现多尺度视觉信息的聚合；加入捷径连接，增强模型对特征的复用，缓解过拟合问题；加入SE注意力机制，增强模型的抗干扰能力；使用余弦退火加速模型收敛，在此基础上，构建深度学习网络模型（BSNet），以实现核桃品种的动态分选。将BSNet模型与ResNet18、ResNet50、ResNet101、DenseNet121、GoogleNet等经典模型进行对比实验，实验结果表明，BSNet模型在自建数据集上的分选平均准确率达到96.13%，优于经典模型，证明所提方法能够有效应用于核桃品种分选。     

火炮多目标测速雷达

本文以测量脱壳弹多目标为例,对火炮多目标测速雷达的测量体制、设备方案,精度等有关技术问题进行了探讨和分析。     

浅谈电力企业日常技术工作的要点——以变压器运行安全与继电保护为例

安全可靠地供电是电力企业的目标,也是电力工作的方向,在日常的工作中要做好电力工作的细节和重点,这样才能在容量越来越、电压越来越高、技术越来越复杂的电力工作中有效提高技术能力和管理水平,达到与电力工作的适应和发展。本研究根据电力企业变压器和继电保护的相关工作,提供了做好日常技术工作的要点,希望共同仁借鉴。     

浅析基于信息控制的防护工程反无人机攻击技术

无人机影响了未来战争形态，被广泛应用于打击重要军事设施。随着弹药的发展，防护工程传统“硬壳式”防护手段越来越力不从心。为突破传统防护思想观念的桎梏，立足信息化战争的特点，基于信息控制的防护工程反无人机攻击技术由此被提出。该技术通过进行非物理破坏式的诱骗、致盲、拦截、消灭等处置方式对无人机目标实施反制，从而使防护工程战时生存能力获得提升，满足使用功能要求。     

旺仁镇第一中学音乐教育现状的调查与研究

本调查研究旨在以旺仁镇第一中学为例,通过问卷调查的方式获取第一手资料,来透视、了解我国农村中学音乐教育的现状和存在的问题,并针对问题做简单的分析,找出问题的原因。     

连发弹丸初速数据处理方法

一种对连发弹丸初速进行测量的小型雷达,通过对弹径小于20mm,连发射速约2200发/分的脱壳穿甲弹的实际测量,验证其测量方法是有效的,而且测量随机误差较小。从而也验证了其数据处理方法是可行的、有效的。     

夏收时我被孤立

暴雨的下午，南方城市的花园小区，我坐在客厅沙发上，捏核桃吃，一个一个在手心挤碎，摊开手掌在碎屑里挑核桃仁，核桃是爸妈从陕西捎来的。     

移动电话的进化历程就是带宽增加的历史

随着移动电话通信方式的更新换代,为了提高每个信道的传输速度,信道的带宽在日益增大.为了满足这种高带宽化的要求,对调制方式和多址接入方式进行了修改(见图A-1).     

Core–Shell Zeolite Microcomposites

Core–shell zeolite composites possessing a core and a shell of different zeolite structure types have been synthesized. A characteristic feature of the obtained composites is the relatively large single‐crystal core and the very thin polycrystalline shell. The incompatibility between the core crystals and the zeolite precursor mixture yielding the shell layer has been circumvented by the adsorption of nanoseeds on the core surface, which induced the crystallization of the shell. The pretreated core crystals are subsequently subjected to a continuous growth in a zeolite precursor mixture. The feasibility of this synthetic approach has been exemplified by the preparation of core–shell β‐zeolite–silicalite‐1 composites. The synthesized composites have been characterized using X‐ray diffraction, high‐resolution transmission electron microscopy, and scanning electron microscopy. The integrity of the shell layer has been tested via N₂‐adsorption measurements on materials comprising a calcined core (β‐zeolite) and a non‐calcined tetrapropylammonium (TPA)‐containing shell, the latter being non‐permeable for the N₂ molecules. These measurements have shown that 86 % of the β‐zeolite crystals are covered with a defect‐free TPA–silicalite‐1 shell after a single hydrothermal treatment, while after three consecutive crystallization steps this value reaches 99 %. The shell integrity of the calcined composite has been studied by the adsorption of butane, toluene, and 1,3,5‐trimethylbenzene, which confirmed the superior performance of the triple‐shell composites.     

Diffraction of a cylindrical wave by a perfectly conducting cylinder enclosed in a metamaterial shell with a negative refractive index

The problem of diffraction of a plane (cylindrical) wave by a perfectly conducting cylinder enclosed in a metamaterial shell is rigorously solved. The influence of the geometric dimensions of the shell, the value of the negative refractive index of the metamaterial medium, and the position of a cylindrical wave source on the field structure in the near zone of the scatterer is investigated. It is found that, in the quasi-optical range of the problem parameters, this structure does not exhibit ideal focusing. It is shown that, there are two types of caustics inside the shell. The first type is related with rays reflected by the surface of the interior cylinder and has one cusp point, and the second type is formed by the geometric-optics rays that are refracted by the outer boundary of the shell and do not fall on the surface of the interior perfectly conducting cylinder. The spatial distribution of the total field amplitude and of the equal-amplitude lines in the near zone of the scatterer is reported. The obtained numerical results are correctly interpreted from the physical viewpoint.     

车内线缆的高空核电磁脉冲响应分析

复杂电磁环境中的车载电子设备受制于高空核电磁脉冲的威胁,其内置线缆的电磁效应与防护决定了特种车辆的生存能力及性能发挥。文中采用基于FTDT算法的电磁仿真软件CST,建立了车辆壳体的电磁模型以及车辆内置线缆布局模型,并仿真分析了车内线缆的高空核电磁脉冲电流电压响应。仿真结果表明,双绞线上响应电压较大而响应电流较小;同轴线的响应电压较小响应电流较大。有屏蔽体的线缆在HEMP照射时的响应电压电流和无屏蔽体时相比显著减小。但是,实际车辆壳体存在孔缝,响应电压电流的在部分频点产生谐振,导致电压电流出现较大值。文中的仿真分析结果对车载电子设备的电磁脉冲防护具有一定的实际工程意义。     

Gas Pickering Emulsion Templated Hollow Carbon for High Rate Performance Lithium Sulfur Batteries

A CO₂ in water nanoparticle stabilized Pickering emulsion is used to template micrometer sized hollow porous nitrogen doped carbon particles for high rate performance lithium sulfur battery. For the first time, nanoparticles serve the dual role of an emulsion stabilizer and a pore template for the shell, directly utilizing in situ generated CO₂ bubbles as template for the core. The minimalistic nature of this method does not require expensive surfactants or additional core templates. Upon polymerization of melamine formaldehyde onto CO₂, a robust polymer/silica composite shell is formed and transformed into a porous shell upon washing. The micrometer‐sized hollow morphology in combination with its nitrogen rich porous shell demonstrates impressive rate capabilities of 670 and 500 mAh g^?1 even at a high rate of 7C and 9C, respectively. This material also possesses excellent cycle durability, exhibiting a low capacity decay of 0.088%/cycle over 300 cycles. Measurement of the shuttle current and impedance provides interesting insight into the polysulfide mass transfer mechanism of hollow structured sulfur hosts.     

Study on the Characteristic of IR Radiation from the Target of a Shell Containing the Cone

In this paper, based on the analysis of the thermal environment where the space target embeds and the study of thermal exchanges between the environment and the space target, the mathematics model of the temperature field for the shell containing the cone is built by using the thermal network method, the temperature and the illuminance value in the detector of the target is calculated, the characteristic of the distribution of temperature and IR radiation from the shell containing the cone is discussed in detail.     

Novel Type‐II InAs/AlSb Core–Shell Nanowires and Their Enhanced Negative Photocurrent for Efficient Photodetection

The control of optical and transport properties of semiconductor heterostructures is crucial for engineering new nanoscale photonic and electrical devices with diverse functions. Core–shell nanowires are evident examples of how tailoring the structure, i.e., the shell layer, plays a key role in the device performance. However, III–V semiconductors bandgap tuning has not yet been fully explored in nanowires. Here, a novel InAs/AlSb core–shell nanowire heterostructure is reported grown by molecular beam epitaxy and its application for room temperature infrared photodetection. The core–shell nanowires are dislocation‐free with small chemical intermixing at the interfaces. They also exhibit remarkable radiative emission efficiency, which is attributed to efficient surface passivation and quantum confinement induced by the shell. A high‐performance core–shell nanowire phototransistor is also demonstrated with negative photoresponse. In comparison with simple InAs nanowire phototransistor, the core–shell nanowire phototransistor has a dark current two orders of magnitude smaller and a sixfold improvement in photocurrent signal‐to‐noise ratio. The main factors for the improved photodetector performance are the surface passivation, the oxide in the AlSb shell and the type‐II bandgap alignment. The study demonstrates the potential of type‐II core–shell nanowires for the next generation of photodetectors on silicon.     

High‐Efficient Deep‐Blue Light‐Emitting Diodes by Using High Quality ZnxCd1‐xS/ZnS Core/Shell Quantum Dots

High‐quality violet‐blue emitting Zn_xCd_1‐xS/ZnS core/shell quantum dots (QDs) are synthesized by a new method, called “nucleation at low temperature/shell growth at high temperature”. The resulting nearly monodisperse Zn_xCd_1‐xS/ZnS core/shell QDs have high PL quantum yield (near to 100%), high color purity (FWHM) <25 nm), good color tunability in the violet‐blue optical window from 400 to 470 nm, and good chemical/photochemical stability. More importantly, the new well‐established protocols are easy to apply to large‐scale synthesis; around 37 g Zn_xCd_1‐xS/ZnS core/shell QDs can be easily synthesized in one batch reaction. Highly efficient deep‐blue quantum dot‐based light‐emitting diodes (QD‐LEDs) are demonstrated by employing the Zn_xCd_1‐xS/ZnS core/shell QDs as emitters. The bright and efficient QD‐LEDs show a maximum luminance up to 4100 cd m^?2, and peak external quantum efficiency (EQE) of 3.8%, corresponding to 1.13 cd A^?1 in luminous efficiency. Such high value of the peak EQE can be comparable with OLED technology. These results signify a remarkable progress, not only in the synthesis of high‐quality QDs but also in QD‐LEDs that offer a practicle platform for the realization of QD‐based violet‐blue display and lighting.     

Diffraction of plane and cylindrical waves by a cylindrical metamaterial shell with a negative refractive index

The problems of scattering of plane and cylindrical waves by a cylindrical metamaterial shell are solved rigorously. The influence of the geometric dimension of the shell, the value of the negative refractive index of the metamaterial medium, and the location of the cylindrical wave source on the near (far) field structure is investigated. It is shown that, in the quasi-opticl region, a caustic with one cusp is formed inside an electrically thick shell and whispering-gallery waves or standing waves are formed in between the facets of an electrically thin shell. It is found that, in the resonance region, reactive (surface) fields with substantial amplitudes are observed near the boundaries of a thin shell.     

Osmotic Pressure Triggered Rapid Release of Encapsulated Enzymes with Enhanced Activity

In this study, a single‐step microfluidic approach is reported for encapsulation of enzymes within microcapsules with ultrathin polymeric shell for controlled release triggered by an osmotic shock. Using a glass capillary microfluidic device, monodisperse water‐in‐oil‐in‐water double emulsion droplets are fabricated with enzymes in the core and an ultrathin middle oil layer that solidifies to produce a consolidated inert polymeric shell with a thickness of a few tens to hundreds of nanometers. Through careful design of microcapsule membranes, a high percentage of cargo release, over 90%, is achieved, which is triggered by osmotic shock when using poly(methyl methacrylate) as the shell material. Moreover, it is demonstrated that compared to free enzymes, the encapsulated enzyme activity is maintained well for as long as 47 days at room temperature. This study not only extends industrial applications of enzymes, but also offers new opportunities for encapsulation of a wide range of sensitive molecules and biomolecules that can be controllably released upon applying osmotic shock.     

Porphyrinic Metal–Organic Frameworks Coated Gold Nanorods as a Versatile Nanoplatform for Combined Photodynamic/Photothermal/Chemotherapy of Tumor

In this paper, a simple, but effective method is reported to construct the core?shell gold nanorod@metal–organic frameworks (AuNR@MOFs) as a multifunctional theranostic platform by using functionalized AuNRs as seed crystal for the growth of porphyrinic MOFs on the surface of AuNR. Such a delicate tunable core?shell composite not only possesses the improved drug loading efficiency, near‐infrared light‐trigger drug release, and fluorescence imaging, but also can produce reactive oxygen species as well as photothermal activity to achieve combined cancer therapy. It is further demonstrated that the camptothecin loaded AuNR@MOFs show distinctively synergistic efficiency for damaging the cancer cell in vitro and inhibiting the tumor growth and metastasis in vivo. The development of this high‐performance incorporated nanostructure will provide more perspectives in the design of versatile nanomaterials for biomedical applications.