一种快速响应型卫星的遥测方案

随着航天技术的发展和应用，快速空间响应型卫星的发展需求脱颖而出，成为当前世界航天领域的新热点。快速响应型卫星主要有研制周期短、成本投入低、承载载荷不确定等特点，本文提出了一种适应快速响应型卫星的遥测方案。     

快速响应空间小卫星热控系统设计及关键技术

随着空间技术的发展,卫星热控系统面临着巨大的设计挑战。首先,根据快速响应空间小卫星的新特点,分析比较了其热控设计与传统设计方法的区别,从而提出了快速响应空间小卫星热控系统的研制流程。然后针对实现快速响应空间小卫星热控系统设计的关键步骤:多轨道极端工况外热流参数的确定、模块化热构架系统和热控系统快速分析技术进行了详细的阐述和介绍。最后,追踪了实现快速响应空间小卫星热控系统研制的新型热控器件的研究和应用。作者认为,时间驱动的热设计理念,稳健、模块、可扩展的热设计方法,以及新型先进智能热控器件的研制是由快速响应空间小卫星的任务特点所决定的必然要求和实现途径。     

遥感卫星滚动式动态任务规划技术

面对应急任务常态化趋势,通过分析卫星任务管控系统快速响应需求,提出了滚动式动态任务规划技术方法,研究了动态任务规划问题的求解过程,分析了动态任务规划滚动时间窗口选取策略、前瞻式任务与资源处理策略和星上资源连续使用原则等。该方法在遥感卫星任务管控系统中的工程化应用将能够大大提升系统应急任务快速响应时效性,降低任务动态调整复杂度,规避星上任务频繁调整风险。该方法将为面向任务快速响应的新一代任务管控系统建设奠定技术基础。     

快速响应星载SAR载荷技术研究

卫星微波遥感系统正朝着多样化方向发展,高性能的大型卫星必不可少,但近年来低成本航天器发射技术正成为研究的热点之一。与此同时,小卫星微波遥感系统技术发展迅速,一些新的概念被提出并得到运用。研究快速响应星载SAR有效载荷技术,有利于提高突发重大灾害的应急监测能力。讨论了雷达模块化、低成本设计、参数优化方法、轨道高度选择和星上实时处理等对快速响应SAR有效载荷系统设计非常重要的技术途径。结合设计实例,给出一种低成本小型星载SAR有效载荷的解决方案和主要指标参数的优化设计方法。     

美军作战快速响应空间计划推动下的卫星发展概况

＂2010年11月,美国作战快速响应空间（ORS）计划的首颗卫星＂作战快速响应空间＂-1（ORS-1）实现了主要集成里程碑。卫星制造主合同商——古德里奇（Goodrich）公司已成功将其光电/红外传感器有效载荷集成到ORS-1卫星的航天器平台上。这项集成工作为该卫星的环境和验收测试铺平了道路,     

美国战术星发展研究

美国战术星项目是美国国防部作战响应空间试验计划的主要技术验证项目。作为目前唯一在轨运行的卫星,TacSat-4卫星为实现作战响应空间提供了“动中通”通信、数据暗渡和蓝军跟踪等相关先进能力,从而提高了作战响应空间系统的通信与覆盖能力、改进了卫星通信需求的能力和体系结构,并且为未来作战响应空间项目的采办提供了依据。另一方面,美国的战术星项目还需要面对军事效果评估和商业策略的挑战。然而,美国战术星的先进技术及军事效果评估结论也为我国未来卫星通信系统的建设以及卫星通信系统对抗装备的发展带来新的思考。     

卫星光通信系统中PIN探测器的空间辐射特性

对空间辐射环境下PIN光电探测器γ射线辐射特性以及粒子辐射特性进行了深入的研究。结果表明两种辐射机制均会对PIN光电探测器造成一定的影响,表现为暗电流噪声增加、响应率下降以及响应带宽下降。在卫星光通信系统结构设计过程中应该更多地考虑空间辐射对暗电流噪声造成的影响。     

航天快速发射需求研究

首先以空间系统的脆弱性、航天发射的成本和技术发展为切入点,阐述了发展航天快速发射的必要性,剖析了航天快速发射的现实需求;其次以自然灾害、局部战争为例,论证了在突发事件中航天快速发射的重要地位和作用。通过对卫星调集数量和发射准备时间进行统计分析,得出现有航天发射水平无法满足需求的能力缺口。     

先进微小卫星平台技术

微小卫星是军用、民用航天领域的一类重要卫星,随着其空间应用领域的拓展和需求量的骤增,传统卫星的定制方式研制模式已经不能适应微小卫星批量化快速研制的需求。哈尔滨工业大学曹喜滨教授率领其研究团队在国家"973"、"863"及国防预先研究等计划支持下,十余年集智攻关,在微小卫星高性能、低成本、快速研制方面取得重要突破。     

微生物快速检测用生物传感器基本特性研究

针对食品卫生现场检测需求,基于三磷酸腺苷(ATP)生物发光原理设计了一种新型的微生物快速检测用生物传感器,并以ATP标准品为检测对象,结合荧光分光光度计对传感器的响应波长、检测时间及响应范围等基本特性进行了初步研究。研究结果表明,该传感器对标准ATP响应迅速,其光学响应波长为550nm;在1~100nmol/L ATP浓度范围内,传感器响应光强信号与ATP浓度之间呈现出良好的正响应关系。此外,通过如加入一定CoA等方式来优化检测试剂配方,可以进一步来改进传感器的检测灵敏度。该传感器在结构上采用集成化设计,具有无需微生物培养、操作简单及响应快速的优点,在食品工业领域快速检测物体表面微生物污染方面具有广泛应用前景。     

自适应设计在电子医疗的应用研究

自适应网页设计是一种目前国内外最新流行的网页设计技术,通过对网页页面的大小调整、重新布局等来满足用户来自不同大小的手持移动设备,如笔记本电脑、平板电脑、智能手机等对网页直接实时访问的需求。在能给用户提供理想的网页视觉体验前提下,大大减少了针对于小屏幕移动设备的网页重新开发成本。文中通过总结现有的国外自适应网页设计方法,提出了一个网页的基本自适应框架,并且基于该框架设计并实现了一整套具有网页自适应功能的电子医疗系统。系统测试表明,较普通不具有自适应功能的网页,利用该框架的自适应网页在页面读取速度与访问时间上有显著的提高。     

Two-Photon Polymerization of Sugar Responsive 4D Microstructures

Stimuli-responsive hydrogels have attracted much attention owing to the versatility of their programmed response in offering intelligent solutions for biomimicry applications, such as soft robotics, tissue engineering, and drug delivery. To achieve the complexity of biomimetic structures, two photon polymerization (2PP) has provided a means of fabricating intricate 3D structures from stimuli-responsive hydrogels. Rapid swelling hydrogel microstructures are advantageous for osmotically driven stimuli-response, where actuation speed, that is reliant on the diffusion of analytes or bioanalytes, can be optimized. Herein, the flexibility of 2PP is exploited to showcase a novel sugar-responsive, phenylboronic acid-based photoresist. This offers a remarkable solution for achieving fast response hydrogel systems that have been often hindered by the volume-dependent diffusion times of analytes to receptor sites. A phenylboronic acid-based photoresist compatible with 2PP is presented to fabricate stimuli-responsive microstructures with accelerated response times. Moreover, microstructures with programmable actuation (i.e., bending and opening) are fabricated using the same photoresist within a one-step fabrication process. By combining the flexibility of 2PP with an easily adaptable photoresist, an accessible fabrication method is showcased for sophisticated and chemo-responsive 3D hydrogel actuators.     

Modulation of Viscoelasticity and HIV Transport as a Function of pH in a Reversibly Crosslinked Hydrogel

Materials that respond to physiological stimuli are important in developing advanced biomaterials for modern therapies. The reversibility of covalent crosslinks formed by phenylboronate (PBA) and salicylhydroxamate (SHA) has been exploited to provide a pH‐responsive gel for application to the vaginal tract. Dynamic rheology reveals that the gel frequency‐dependent viscoelastic properties are modulated by pH. At pH 4.8 the viscous component dominates throughout most of the frequency range. As the pH increases, the characteristic relaxation time continues to increase while the G′_Plateau levels off above pH 6. At pH 7.5, the elastic component dominates throughout the frequency sweep and is predominately independent of frequency. Particle tracking assesses the transport of both fluorescently labeled HIV‐1 and 100‐nm latex particles in the PBA–SHA crosslinked gel as a function of pH. At pH 4.8 the ensemble‐averaged mean squared displacement at lag times greater than three seconds reveals that transport of the HIV‐1 and 100‐nm particles becomes significantly impeded by the matrix, exhibiting diffusion coefficients less than 0.0002 µm² s^?1. This pH‐responsive gel thus displays properties that have the potential to significantly reduce the transport of HIV‐1 to susceptible tissues and thus prevent the first stage of male‐to‐female transmission of HIV‐1.     

Multi‐Stimuli‐Responsive Microcapsules for Adjustable Controlled‐Release

Novel multi‐stimuli‐responsive microcapsules with adjustable controlled‐release characteristics are prepared by a microfluidic technique. The proposed microcapsules are composed of crosslinked chitosan acting as pH‐responsive capsule membrane, embedded magnetic nanoparticles to realize “site‐specific targeting”, and embedded temperature‐responsive sub‐microspheres serving as “micro‐valves”. By applying an external magnetic field, the prepared smart microcapsules can achieve targeting aggregation at specific sites. Due to acid‐induced swelling of the capsule membranes, the microcapsules exhibit higher release rate at specific acidic sites compared to that at normal sites with physiological pH. More importantly, through controlling the hydrodynamic size of sub‐microsphere “micro‐valves” by regulating the environment temperature, the release rate of drug molecules from the microcapsules can be flexibly adjusted. This kind of multi‐stimuli‐responsive microcapsules with site‐specific targeting and adjustable controlled‐release characteristics provides a new mode for designing “intelligent” controlled‐release systems and is expected to realize more rational drug administration.     

Greatly Enhanced Thermal Contraction at Room Temperature by Carbon Nanotubes

A crosslinked polyarylamide polymer exhibits novel photothermal behavior, that is, reversible giant contraction in response to near infrared irradiation in addition to normal thermal expansion. Such reversibility is seldom found in a polymeric system. Due to the amphiphilic nature of the benzocyclobutene‐containing triblock copolymer precursor with polyarylamide interacting strongly with few‐walled carbon nanotubes (FWCNTs), they are dispersed extremely well in the polymer solution at a loading up to at least 5 wt%. Also, strained carbon double bonds on FWCNTs can directly form covalent linkages with the benzocyclobutene groups on the polymer chains via cyclo‐addition. The incorporation of FWCNTs increases mechanical stiffness two‐fold. Exploiting the ability of FWCNTs to effectively convert photon energy into heat and to provide conductive pathways, the NIR‐induced unexpected contraction stress can be further increased dramatically. The systematic study suggests that there is an optimal CNT concentration. At 3 wt% FWCNTs, the enhancement factor for contraction stress is almost 24: 166 kPa with 3 wt% FWCNTs versus 7 kPa without FWCNTs. The colossal photothermal contraction stress generated by this new composite film at ambient condition upon NIR stimulation can lead to the development of new NIR actuators, for example, for biological applications, and create new material platforms for green energy conversion.     

Understanding the Shape Memory Behavior of Self‐Bending Materials and Their Use as Sensors

By depositing layers composed of poly (N‐isopropylacrylamide)‐based microgels and the polyelectrolyte polydiallyldimethylammonium chloride on a flexible substrate, responsive materials that bend upon drying can be fabricated; the extent of the bending depends on atmospheric humidity. This study shows that the bending conformation/direction can be templated, and exhibits shape memory. Detailed examination of the bilayer system leads to an understanding of the phenomena leading to this behavior. By close examination of microscopy images and diffraction patterns, this study is able to determine that the dried polymer‐based layer is composed of both amorphous and crystalline phases; the amorphous phase can readily absorb water, which results in actuation, while the crystalline phases template the bending characteristics of the device. With an understanding of the bending behavior of the devices, this study is able to generate humidity sensors by interfacing them with stretchable strain sensors, which are also developed specifically for the bendable materials.     

响应式网页设计与实现

响应式网页设计能够让网页的表现效果达到用户的需求,越来越多的响应式网页设计被广泛的应用。论文在阐述响应式网页概念的基础上,分析了响应式网页设计的优势优势,给出了响应式网页设计的关键技术。     

Hydrogels That Actuate Selectively in Response to Organophosphates

Nerve agents and pesticides represent a category of extremely toxic organophosphate compounds (OPs) that irreversibly inhibit the enzyme acetylcholinesterase, disturbing transmission in the synaptic clefts of muscles and nerves. Protection from these compounds necessitates the development of breathable barriers that can selectively block the passage of OPs. Hydrogels prepared from acrylamide, N,N′‐methylenebis(acrylamide), N,N′‐bis(acryloyl)cystamine, and hydrophilic pendant oximes are herein prepared, showing the ability to decontaminate and respond to the presence of OPs through a change in swelling. The oxime‐based hydrogels show selective response only to malaoxon when tested against chemicals that are found in sweat as well as other reactive chemicals that are found in the environment. Pore sealing is demonstrated in perforated equilibrated gels within 3–4 h after the addition of malaoxon, showing actuation of the gel in response to organophosphates. This strategy demonstrates the ability to couple oxime‐based decontamination and disulfide chemistry to produce hydrogels that can decontaminate organophosphate compounds, sense the decontamination product, and transduce this sensing response into actuation of the gel, which can be used to close pores in gel sheets or between fibers in a protective fabric coating.     

Engineering DNA-Grafted Quatsomes as Stable Nucleic Acid-Responsive Fluorescent Nanovesicles

The development of artificial vesicles into responsive architectures capable of sensing the biological environment and simultaneously signaling the presence of a specific target molecule is a key challenge in a range of biomedical applications from drug delivery to diagnostic tools. Herein, the rational design of biomimetic DNA-grafted quatsome (QS) nanovesicles capable of translating the binding of a target molecule to amphiphilic DNA probes into an optical output is presented. QSs are synthetic lipid-based nanovesicles able to confine multiple organic dyes at the nanoscale, resulting in ultra-bright soft materials with attractiveness for sensing applications. Dye-loaded QS nanovesicles of different composition and surface charge are grafted with fluorescent amphiphilic nucleic acid-based probes to produce programmable FRET-active nanovesicles that operate as highly sensitive signal transducers. The photophysical properties of the DNA-grafted nanovesicles are characterized and the highly selective, ratiometric detection of clinically relevant microRNAs with sensitivity in the low nanomolar range are demonstrated. The potential applications of responsive QS nanovesicles for biosensing applications but also as functional nanodevices for targeted biomedical applications is envisaged.