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1.
聚氯乙烯是由氯乙烯单体经过聚合形成的一种树脂,加以辅料通过挤塑或压延的方式产生的。它作为一种包装材料,具有较好的硬度和刚性等优点,广泛用于固体药品(片剂、胶囊剂等)的泡罩包装中。为保证药包材质量,确保药品使用的安全有效,对其理化指标进行质量控制。其中易氧化物就是一个常见而又比较重要的化学性能指标,它测定样品中可提取的还原性物质。  相似文献   

2.
Hentschel K 《NTM》2011,19(1):5-40
The manipulation of materials, and to some extent also their systematic classification, form an integral part of the skills and culture of all societies. Yet it took long for proper sciences (e.g., metallurgy, glass technology, polymer chemistry or solid-state physics) to develop out of many processing procedures, tapping the accumulated knowledge about specific material characteristics. In the late 20th century an overarching science of workable materials emerged: materials science. This concept and term originated from major boosts in materials research during WWII and the Cold War, first financed by the U.S. Department of Defense and the Advanced Research Project Agency (ARPA). The COSMAT-Report from 1974, written by the American Presidential Science Advisory Committee??s ?Committee on the Survey of Materials Science and Engineering" four years after its inception, and subsequent reports heralded in the second institutionalization phase of materials science in the USA and with some delay also elsewhere. As the field continued to expand, the demand grew from within in the late 1990s for disciplinary status. This article sorts these claims from the various camps (by solid state physicists vs. chemists vs. engineers) and sets them in the context of unfolding institutional change. The developments within the German-speaking realm, thus far unduly neglected in these debates, are added. I close with a systematic discussion of eight indicator arguments for or against a convergence of this complex field of research into a single coherent discipline. Against Bensaude-Vincent??s (2001: 242) thesis that materials science still is an ??aggregation of fragments of knowledge", I argue that by 2010 materials science did indeed achieve disciplinary status in a historically rare and enduring process of discipline formation through ??emergence by integration" rather than by differentiation.  相似文献   

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Artificial molecular machines are able to produce and exploit precise nanoscale actuations in response to chemical or physical triggers. Recent scientific efforts have been devoted to the integration, orientation, and interfacing of large assemblies of molecular machines in order to harness their collective actuations at larger length scale and up to the generation of macroscopic motions. Making use of such “hierarchical mechanics” represents a fundamentally new approach for the conception of stimuli-responsive materials. Furthermore, because some molecular machines can function as molecular motors—which are capable of cycling a unidirectional motion out of thermodynamic equilibrium and progressively increasing the work delivered to their environment—one can expect unique opportunities to design new kinds of mechanically active materials and devices capable of autonomous behavior when supplied by an external source of energy. Recently reported achievements are summarized, including the integration of molecular machines at surfaces and interfaces, in 3D self-assembled materials, as well as in liquid crystals and polymer materials. Their detailed functioning principles as well as their functional properties are discussed along with their potential applications in various domains such as sensing, drug delivery, electronics, optics, plasmonics, and mechanics.  相似文献   

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Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency (PCE) along with very low material costs. Since the first report on a long‐term durable solid‐state perovskite solar cell with a PCE of 9.7% in 2012, a PCE as high as 19.3% was demonstrated in 2014, and a certified PCE of 17.9% was shown in 2014. Such a high photovoltaic performance is attributed to optically high absorption characteristics and balanced charge transport properties with long diffusion lengths. Nevertheless, there are lots of puzzles to unravel the basis for such high photovoltaic performances. The working principle of perovskite solar cells has not been well established by far, which is the most important thing for understanding perovksite solar cells. In this review, basic fundamentals of perovskite materials including opto‐electronic and dielectric properties are described to give a better understanding and insight into high‐performing perovskite solar cells. In addition, various fabrication techniques and device structures are described toward the further improvement of perovskite solar cells.  相似文献   

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Simultaneously improving the energy density and power density of electrochemical energy storage systems is the ultimate goal of electrochemical energy storage technology. An effective strategy to achieve this goal is to take advantage of the high capacity and rapid kinetics of electrochemical proton storage to break through the power limit of batteries and the energy limit of capacitors. This article aims to review the research progress on the physicochemical properties, electrochemical performa...  相似文献   

9.
The development, characterization, and exploitation of novel materials based on the assembly of molecular components is an exceptionally active and rapidly expanding field. For this reason, the topic of molecule-based materials (MBMs) was chosen as the subject of a workshop sponsored by the Chemical Sciences Division of the United States Department of Energy. The purpose of the workshop was to review and discuss the diverse research trajectories in the field from a chemical perspective, and to focus on the critical elements that are likely to be essential for rapid progress. The MBMs discussed encompass a diverse set of compositions and structures, including clusters, supramolecular assemblies, and assemblies incorporating biomolecule-based components. A full range of potentially interesting materials properties, including electronic, magnetic, optical, structural, mechanical, and chemical characteristics were considered. Key themes of the workshop included synthesis of novel components, structural control, characterization of structure and properties, and the development of underlying principles and models. MBMs, defined as “useful substances prepared from molecules or molecular ions that maintain aspects of the parent molecular framework” are of special significance because of the capacity for diversity in composition, structure, and properties, both chemical and physical. Key attributes are the ability in MBMs to access the additional dimension of multiple length scales and available structural complexity via organic chemistry synthetic methodologies and the innovative assembly of such diverse components. The interaction among the assembled components can thus lead to unique behavior. A consequence of the complexity is the need for a multiplicity of both existing and new tools for materials synthesis, assembly, characterization, and theoretical analysis. For some technologically useful properties, e.g., ferro- or ferrimagnetism and superconductivity, the property is not a property of a molecule or ion; it is a cooperative solid-state (bulk) property—a property of the entire solid. Hence, the desired properties are a consequence of the interactions between the molecules or ions, and understanding the solid-state structure as well as methods to predict, control, and modulate the structure are essential to understanding and manipulating such behaviors. As challenging as this is, molecules enable a substantially greater ability of control than atoms as building blocks for new materials and thus are well positioned to contribute significantly to new materials. The diversity of components and processes leads to the recognition of the critical role of cross-disciplinary research, including not only that between traditionally different areas within chemistry, but also between chemistry and biochemistry, physics, and a number of engineering disciplines. Enhancing communication and active collaboration between these groups was seen as a critical goal for the research area.  相似文献   

10.
Biomolecular piezoelectric materials are considered a strong candidate material for biomedical applications due to their robust piezoelectricity, biocompatibility, and low dielectric property. The electric field has been found to affect tissue development and regeneration, and the piezoelectric properties of biological materials in the human body are known to provide electric fields by pressure. Therefore, great attention has been paid to the understanding of piezoelectricity in biological tissues and its building blocks. The aim herein is to describe the principle of piezoelectricity in biological materials from the very basic building blocks (i.e., amino acids, peptides, proteins, etc.) to highly organized tissues (i.e., bones, skin, etc.). Research progress on the piezoelectricity within various biological materials is summarized, including amino acids, peptides, proteins, and tissues. The mechanisms and origin of piezoelectricity within various biological materials are also covered.  相似文献   

11.
Soft matter systems and materials are moving toward adaptive and interactive behavior, which holds outstanding promise to make the next generation of intelligent soft materials systems inspired from the dynamics and behavior of living systems. But what is an adaptive material? What is an interactive material? How should classical responsiveness or smart materials be delineated? At present, the literature lacks a comprehensive discussion on these topics, which is however of profound importance in order to identify landmark advances, keep a correct and noninflating terminology, and most importantly educate young scientists going into this direction. By comparing different levels of complex behavior in biological systems, this Viewpoint strives to give some definition of the various different materials systems characteristics. In particular, the importance of thinking in the direction of training and learning materials, and metabolic or behavioral materials is highlighted, as well as communication and information-processing systems. This Viewpoint aims to also serve as a switchboard to further connect the important fields of systems chemistry, synthetic biology, supramolecular chemistry and nano- and microfabrication/3D printing with advanced soft materials research. A convergence of these disciplines will be at the heart of empowering future adaptive and interactive materials systems with increasingly complex and emergent life-like behavior.  相似文献   

12.
The term “engineered zeolitic materials” refers to a class of materials with a rationally designed pore system and active‐sites distribution. They are primarily made of crystalline microporous zeolites as the main building blocks, which can be accompanied by other secondary components to form composite materials. These materials are of potential importance in many industrial fields like catalysis or selective adsorption. Herein, critical aspects related to the synthesis and modification of such materials are discussed. The first section provides a short introduction on classical zeolite structures and properties, and their conventional synthesis methods. Then, the motivating rationale behind the growing demand for structural alteration of these zeolitic materials is discussed, with an emphasis on the ongoing struggles regarding mass‐transfer issues. The state‐of‐the‐art techniques that are currently available for overcoming these hurdles are reviewed. Following this, the focus is set on core–shell composites as one of the promising pathways toward the creation of a new generation of highly versatile and efficient engineered zeolitic substances. The synthesis approaches developed thus far to make zeolitic core–shell materials and their analogues, yolk–shell, and hollow materials, are also examined and summarized. Finally, the last section concisely reviews the performance of novel core–shell, yolk–shell, and hollow zeolitic materials for some important industrial applications.  相似文献   

13.
Semitransparent solar cells (ST-SCs) have received great attention due to their promising application in many areas, such as building integrated photovoltaics (BIPVs), tandem devices, and wearable electronics. In the past decade, perovskite solar cells (PSCs) have revolutionized the field of photovoltaics (PVs) with their high efficiencies and facile preparation processes. Due to their large absorption coefficient and bandgap tunability, perovskites offer new opportunities to ST-SCs. Here, a general overview is provided on the recent advances in ST-PSCs from materials and devices to applications and some personal perspectives on the future development of ST-PSCs.  相似文献   

14.
The exploration of the utilization of sustainable, green energy represents one way in which it is possible to ameliorate the growing threat of the global environmental issues and the crisis in energy. Moisture, which is ubiquitous on Earth, contains a vast reservoir of low-grade energy in the form of gaseous water molecules and water droplets. It has now been found that a number of functionalized materials can generate electricity directly from their interaction with moisture. This suggests that electrical energy can be harvested from atmospheric moisture and enables the creation of a new range of self-powered devices. Herein, the basic mechanisms of moisture-induced electricity generation are discussed, the recent advances in materials (including carbon nanoparticles, graphene materials, metal oxide nanomaterials, biofibers, and polymers) for harvesting electrical energy from moisture are summarized, and some strategies for improving energy conversion efficiency and output power in these devices are provided. The potential applications of moisture electrical generators in self-powered electronics, healthcare, security, information storage, artificial intelligence, and Internet-of-things are also discussed. Some remaining challenges are also considered, together with a number of suggestions for potential new developments of this emerging technology.  相似文献   

15.
Achieving nanostructured or hierarchical hybrid architectures involves cross‐cutting synthetic strategies where all facettes of chemistry (organic, polymers, solid‐state, physical, materials chemistries, biochemistry, etc…?), soft matter and ingenious processing are synergistically coupled. These cross‐cutting approaches are in the vein of bio‐inspired synthesis strategies where the integration of different areas of expertise allows the development of complex systems of various shapes with perfect mastery at different size scales, composition, porosity, functionality, and morphology. These strategies coined “Integrative Chemistry” open a land of opportunities to create advanced hybrid materials with organic‐inorganic or bio‐inorganic character. These hybrid materials represent not only a new field of basic research where creative chemists can express themselves, but also, via their remarkable new properties and multifunctional nature, hybrids are allowing the emergence of innovative industrial applications in extremely diverse fields.  相似文献   

16.
中间相沥青制备高密度高强度炭/石墨材料   总被引:2,自引:0,他引:2  
以在不同氧化温度下制备的氧化中间相沥青为原料制备了具有不同密度的炭/石墨材料, 根据对样品物理性能和微观结构的研究得出最佳的工艺条件. 以150MPa压制的坯体经过2200℃石墨化后得到具有高密度(2.02g/cm3)、低孔率(2.03%)、大体积收缩(44.86%)、高的弯曲强度和压缩强度(70.3和123.3MPa)的样品. 该样品具有均匀致密的结构. 实验证明, 氧化中间相沥青是制备高性能炭石墨材料良好的前驱体.  相似文献   

17.
Conjugated polymers (CPs) possess a unique set of features setting them apart from other materials. These properties make them ideal when interfacing the biological world electronically. Their mixed electronic and ionic conductivity can be used to detect weak biological signals, deliver charged bioactive molecules, and mechanically or electrically stimulate tissues. CPs can be functionalized with various (bio)chemical moieties and blend with other functional materials, with the aim of modulating biological responses or endow specificity toward analytes of interest. They can absorb photons and generate electronic charges that are then used to stimulate cells or produce fuels. These polymers also have catalytic properties allowing them to harvest ambient energy and, along with their high capacitances, are promising materials for next-generation power sources integrated with bioelectronic devices. In this perspective, an overview of the key properties of CPs and examination of operational mechanism of electronic devices that leverage these properties for specific applications in bioelectronics is provided. In addition to discussing the chemical structure–functionality relationships of CPs applied at the biological interface, the development of new chemistries and form factors that would bring forth next-generation sensors, actuators, and their power sources, and, hence, advances in the field of organic bioelectronics is described.  相似文献   

18.
分别采用直接沉淀法和快速沉淀法成功地制备了易于微孔道填充的纳米Cu O粉末。直接沉淀法的铜源是无水Cu SO4,沉淀剂是Na2CO3;快速沉淀法的铜源是Cu(CH3COO)2·H2O,沉淀剂是Na OH。通过XRD、SEM、TEM和SAED等分析手段表征产物的晶体结构、微观形貌及晶粒尺寸。结果表明,直接沉淀法的陈化时间对制备样品形貌和结构有影响。当前躯体陈化时间为3 h时,直接沉淀法制备的Cu O纳米颗粒平均粒径约为25 nm;快速沉淀法制备的Cu O纳米颗粒平均粒径约为6 nm。与直接沉淀法相比,快速沉淀法制备的纳米Cu O粒径更小、颗粒分散更均匀。  相似文献   

19.
Following the ever‐expanding technological demands, printed electronics has shown palpable potential to create new and commercially viable technologies that will benefit from its unique characteristics, such as, large‐area and wide range of substrate compatibility, conformability and low‐cost. Through the last few decades, printed/solution‐processed field‐effect transistors (FETs) and circuits have witnessed immense research efforts, technological growth and increased commercial interests. Although printing of functional inks comprising organic semiconductors has already been initiated in early 1990s, gradually the attention, at least partially, has been shifted to various forms of inorganic semiconductors, starting from metal chalcogenides, oxides, carbon nanotubes and very recently to graphene and other 2D semiconductors. In this review, the entire domain of printable inorganic semiconductors is considered. In fact, thanks to the continuous development of materials/functional inks and novel design/printing strategies, the inorganic printed semiconductor‐based circuits today have reached an operation frequency up to several hundreds of kilohertz with only a few nanosecond time delays at the individual FET/inverter levels; in this regard, often circuits based on hybrid material systems have been found to be advantageous. At the end, a comparison of relative successes of various printable inorganic semiconductor materials, the remaining challenges and the available future opportunities are summarized.  相似文献   

20.
Room‐temperature operating means a profound reduction of volume, power consumption, and cost for infrared (IR) photodetectors, which promise a wide range of applications in both military and civilian areas, including individual soldier equipment, automatic driving, etc. Inspired by this fact, since the beginning of 1990s, great efforts have been made in the development of uncooled thermal detectors. During the last two decades, similar efforts have been devoted using IR photon detectors, especially based on photovoltaic effects. Herein, the proven technologies, which have been commercialized with a large format, like InGaAs/InP pin diodes, InAsSb barrier detectors, and high‐operating‐temperature HgCdTe devices, are reviewed. The newly developed technology is emphasized, which has shown unique superiority in detecting mid‐wavelength and long‐wavelength IR signals, such as quantum cascade photodetectors. Finally, brand‐new concept devices based on 2D materials are introduced, which are demonstrated to provide additional degrees of freedom in designing and fabricating room‐temperature IR devices, for example, the construction of multi‐heterojunctions without introducing lattice strain, the convenient integration of optical waveguides and electronic gratings. All information provided here aims to supply a full view of the progress and challenges of room‐temperature IR detectors.  相似文献   

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