An alternative method for the certification of the sulfur mass fraction in coal Standard Reference Materials

The S mass fractions of coal SRMs 2682b, 2684b, and 2685b are certified by direct comparison with coal SRMs 2682a, 2684a, and 2685a, respectively, using high-temperature combustion analysis with infrared (IR) absorption detection. The S mass fractions of the “a” materials used for calibration were previously determined by means of isotope-dilution thermal-ionization mass spectrometry (ID-TIMS). Therefore, the comparisons performed with the combustion–IR absorption method establish direct traceability links to accurate and precise ID-TIMS measurements. The expanded uncertainties associated with the certified S mass fractions are of approximately the same magnitude as would be expected for the ID-TIMS methodology. An important aspect of these certifications is that each “b” material is essentially identical with the corresponding “a” material, because both were produced from the same bulk, homogenized coal. As a test of the efficacy of the new certification approach when calibrant and unknown are not identical, the S mass fraction of coal SRM 2683b has been determined by direct comparison to coal SRM 2683a. These two coals, which have both previously been analyzed with ID-TIMS, are different in terms of S content and other properties. Whereas the S mass fraction for SRM 2683b determined with the new methodology agrees statistically with the ID-TIMS value, there is reason for caution in such cases. In addition to the usefulness of the alternative approach for certification activities within NIST, this approach might also be an excellent way of establishing NIST traceability during the value assignment process for reference materials not issued by NIST. Further research is needed, however, to understand better the scope of applicability.     

电化学储能研究22年回顾

本文回顾了22年来作者的电化学储能研究活动,共分三个部分. 第一部分叙述高比能量、高比功率储能器件研究,包括锂硫电池研究（硫复合正极材料、锂硫电池制作、锂硼合金作为锂硫电池负极、硫-锂离子电池新体系）、超级电容器研究（超级活性炭、以酚醛树脂为原料制备电容炭、碳纳米管阵列中寄生准电容储能材料、氧化镍干凝胶准电容储能材料、归纳出电容炭材料的性能要求、电容器研制、确定“第四类”超级电容器）、锂离子电池研究（锂离子电池与可再生燃料电池的对决、双变价元素正极材料、磷酸钴锂正极材料、高功率锂离子电池的制作）. 第二部分叙述规模储能电池研究,包括液流电池新体系研究（蓄电与电化学合成的双功能液流电池、全金属化合物单液流电池、有机化合物正极的单液流电池）、致力于振兴铅酸电池（推广铅蓄电池新技术、铅炭电池的研究、铅酸电池新型板栅的研究）,储能电池（站）的经济效益计算方法. 第三部分叙述电动汽车发展路线研究,包括氢能燃料电池电动汽车、纯电动汽车与混合动力汽车、对我国电动汽车发展路线的建议、力争电动汽车补贴的合理化、坚守电动汽车“节能减排”宗旨、提出“发电直驱电动车”. 最后的结束语谈了三点感悟.     

Filled Polysilsesquioxanes: A New Approach to Chemical Sensing

Summary : In an attempt to investigate new polymeric materials as constituents of an e-nose we focus our attention on a new emerging class of versatile three-dimensional polyhedral silicon polymers, called polysilsesquioxanes, containing nanosized inorganic cages. Such hybrid amphiphilic materials offer exceptional opportunities to create composites with singular properties. In particular we found that the polyhedral organosilsesquioxane (POSS) cages covalently attached to the polymer backbone as side-chain act as an “internal” filler with a nanometric homogeneous dispersion. We show how it is possible to fabricate sensing devices based on selected POSS matrix and, by a suitable choice of other “external” home-made fillers, (e.g. graphite, copper, silicon, zinc and their alloys) obtained by mechanical milling the response of the resulting composites towards different classes of compounds can be tuned. In particular we fabricated a new high sensitive relative humidity device, exhibiting a fivefold response change for relative humidity changing in the range 0% to 100%. This behaviour can not be modelled on the basis of the matrix swelling operating mechanism. Rather, the combined effect of the matrix and the filler has to be invoked in order to explain the formation of nanopores inside the material that are responsible of the porous behavior of our sensors.     

Rational material design of Li-excess metal oxides with disordered rock salt structure

This review article summarizes recent research development on a new class of electrode materials with a cation-disordered rock salt structure for energy storage applications. Historically, oxide-based electrode materials with the disordered rock salt structure are regarded as “electrochemically inactive.” However, recent experimental and theoretical research reveals that many oxides with the disordered rock salt structure can be utilized as high-capacity electrode materials, which deliver a much larger reversible capacity compared with traditional and cation ordered layered materials used for practical battery applications. For these emerging electrode materials, higher energy density is achieved relying on anionic and/or cationic redox as multi-electron reactions. Moreover, this anionic/cationic redox for Li-excess materials with the rock salt structure is effectively activated for nano-sized materials. These new trends for the material design on high-capacity electrode materials are highlighted and the future direction to design Li/Na insertion materials for energy storage applications is outlooked.     

All‐Nanoporous Hybrid Membranes: Redefining Upper Limits on Molecular Separation Properties

New membrane‐based molecular separation processes are an essential part of the strategy for sustainable chemical production. A large literature on “hybrid” or “mixed‐matrix” membranes exists, in which nanoparticles of a higher‐performance porous material are dispersed in a polymeric matrix to boost performance. We demonstrate that the hybrid membrane concept can be redefined to achieve much higher performance if the membrane matrix and the dispersed phase are both nanoporous crystalline materials, with no polymeric phase. As the first example of such a system, we find that surface‐treated nanoparticles of the zeolite MFI can be incorporated in situ during growth of a polycrystalline membrane of the MOF ZIF‐8. The resulting all‐nanoporous hybrid membrane shows propylene/propane separation characteristics that exceed known upper‐bound performance limits defined for polymers, nanoporous materials, and polymer‐based hybrid membranes. This serves as a starting point for a new generation of chemical separation membranes containing interconnected nanoporous crystalline phases.     

Supramolecular Strategies for the Recycling of Homogeneous Catalysts

Supramolecular approaches are increasingly used in the development of homogeneous catalysts and they also provide interesting new tools for the recycling of metal-based catalysts. Various non-covalent interactions have been utilized for the immobilization homogeneous catalysts on soluble and insoluble support. By non-covalent anchoring the supported catalysts obtained can be recovered via (nano-) filtration or such catalytic materials can be used in continuous flow reactors. Specific benefits from the reversibility of catalyst immobilization by non-covalent interactions include the possibility to re-functionalize the support material and the use as “boomerang” type catalyst systems in which the catalyst is captured after a homogeneous reaction. In addition, new reactor design with implemented recycling strategies becomes possible, such as a reverse-flow adsorption reactor (RFA) that combines a homogeneous reactor with selective catalyst adsorption/desorpion. Next to these non-covalent immobilization strategies, supramolecular chemistry can also be used to generate the support, for example by generation of self-assembled gels with catalytic function. Although the stability is a challenging issue, some self-assembled gel materials have been successfully utilized as reusable heterogeneous catalysts. In addition, catalytically active coordination cages, which are frequently used to achieve specific activity or selectivity, can be bound to support by ionic interactions or can be prepared in structured solid materials. These new heterogenized cage materials also have been used successfully as recyclable catalysts.     

Odds and Trends: Recent Developments in the Chemistry of Odorants

Fragrance chemistry is, together with the closely related area of flavor chemistry, one of the few domains, if not the only one, in which chemists can immediately experience structure–activity relationships. This review presents structure–odor correlations and olfactophore models for the main odor notes of perfumery: “fruity”, “marine”, “green”, “floral”, “spicy”, “woody”, “amber”, and “musky”. New trendsetters and so‐called captive odorants of these notes are introduced, and recent activities and highlights in fragrance chemistry are summarized. The design of odorants, their chemical synthesis, and their use in modern perfumery is discussed. Our selection is guided and illustrated by creative fragrances, and features new odorants which encompassed current trends in perfumery. New odorants for grapefruit and blackcurrant, for galbanum, and leafy top notes are presented. Compounds with fashionable marine, ozonic, and aquatic facets are treated, as well as new odorants for classical lily‐of‐the‐valley, rose, and jasmine accords. Compounds with sweet and spicy tonalities are also discussed, as are the most recent developments for woody notes such as sandalwood and vetiver. We conclude with musky and ambery odorants possessing uncommon or unusual structural features. Some odor trends and effects are illustrated by microencapsulated fragrance samples, and areas where there is need for the development of new synthetic materials and methodologies are pointed out. Thus, chemists are invited to explore fragrance chemistry and participate in the design and synthesis of new odorants. This review gives the latest state of the art of the subject.     

Recycling concepts for polyurethanes and polycarbonate

The opinion is that all thermoplastics are infinitely recyclable, while crosslinked polyurethanes (PUR) and thermosets are not recyclable. The present paper uses comparative data to show that the waste management problem associated with crosslinked PUR materials has been largely overcome on a pilot-plant scale. Direct and indirect material recycling as well as thermal recycling are discussed. A direct recycling method in which granulated PUR-RIM scrap is made to “flow” under heat and pressure to re-mould it, is quoted as evidence that crosslinked polyurethane elastomers can be reclaimed and reused in a similar manner to thermoplastics. This process is called “compression molding”. Recycling methods for thermoplastics under consideration from an early stage, as well as entirely new possibilities that are emerging, are demonstrated, using polycarbonate Makrolon® as an example.     

Density functional theory and pseudopotentials: A panacea for calculating properties of materials

Although our microscopic view of solids is still evolving, for a large class of materials one can construct a useful first principles or “standard model” of solids which is sufficiently robust to explain and predict many physical properties. Both electronic and structural properties can be studied, and the results of the first-principles calculations can be used to predict new materials, formulate empirical theories and simple formulas to compute material parameters, and explain trends. A discussion of the microscopic approach, applications, and empirical theories is given here, and some recent results on nanotubes, hard materials, and fullerenes are presented. © 1997 John Wiley & Sons, Inc.     

Renaissance of Organic Triboluminescent Materials

Solid‐state luminescence of organic dyes is an elusive frontier, and understanding and designing solid‐state stimuli‐responsive materials is not trivial. “Mechanoluminescence” (ML) or “triboluminescence” (TL), which is associated with fracture or force‐initiated luminescence from a material, is currently attracting new interest. Fracturing the surfaces of organic crystals ordered in noncentrosymmetric space groups can electronically excite the surface and neighboring molecules through piezo‐ or pyroelectric effects, and this can result in luminescence when the molecules relax back to their ground states. The combined duration of these two consecutive phenomena leads to force‐generated luminescence or TL. Although TL has been known for a very long time, examples of TL‐active materials are scarce, but are increasing as synthetic and characterization procedures develop. The question is now whether the relatively rare phenomenon of TL needs to be reevaluated to obtain a broader understanding of the subject.     

Radiation processing of natural polymers: The IAEA contribution

Radiation processing offers a clean and additive-free method for preparation of value-added novel materials based on renewable, non-toxic, and biodegradable natural polymers. Crosslinked natural polymers can be used as hydrogel wound dressings, face cleaning cosmetic masks, adsorbents of toxins, and non-bedsore mats; while low molecular weight products show antibiotic, antioxidant, and plant-growth promoting properties. Recognizing the potential benefits that radiation technology can offer for processing of natural polymers into useful products, the IAEA implemented a coordinated research project (CRP) on “Development of Radiation-processed products of Natural Polymers for application in Agriculture, Healthcare, Industry and Environment”. This CRP was launched at the end of 2007 with participation of 16 MS to help connecting radiation technology and end-users to derive enhanced benefits from these new value-added products of radiation-processed natural materials. In this paper the results of activities in participating MS related to this work will be presented.     

Tailor-made polymers through selective modification

Despite being generally regarded as “mass materials” without a high degree of sophistication in public, plastics are revolutionizing our life with new innovations on a day-to-day basis. While stunning developments like self-healing polymers or high-performance nanocomposites are still in a basic phase of their development, recent years have seen “commodity” materials like polyolefins evolving into performance polymers with a variety of technically demanding applications. This has become possible through a selective modification of the material properties on all structural and productional levels: Catalyst and chain structure, copolymerisation and phase morphology, conventional and reactive compounding, processing and crystallinity. A state-of-art review and an outlook on future developments for polyolefins in general, but polypropylene in particular, is given.     

All‐Inorganic Nanocrystals as a Glue for BiSbTe Grains: Design of Interfaces in Mesostructured Thermoelectric Materials

Nano‐ and mesostructuring is widely used in thermoelectric (TE) materials. It introduces numerous interfaces and grain boundaries that scatter phonons and decrease thermal conductivity. A new approach has been developed for the rational design of the interfaces in TE materials by using all‐inorganic nanocrystals (NCs) that serve as a “glue” for mesoscopic grains. For example, circa 10 nm Bi NCs capped with (N₂H₅)₄Sb₂Te₇ chalcogenidometallate ligands can be used as an additive to BiSbTe particles. During heat treatment, NCs fill up the voids between particles and act as a “glue”, joining grains in hot‐pressed pellets or solution‐processed films. The chemical design of NC glue allowed the selective enhancement or decrease of the majority‐carrier concentration near the grain boundaries, and thus resulted in doped or de‐doped interfaces in granular TE material. Chemically engineered interfaces can be used as to optimize power factor and thermal conductivity.     

Localized growth of materials from amorphous hydrogenated carbon by barrier-discharge treatment of benzene vapor-argon mixture

The possibility of a localized growth of materials from amorphous hydrogenated carbon by the barrier-discharge treatment of a benzene vapor mixture with argon has been shown. Two types of material are produced, the “columnar” black entities of ～100 μm in diameter and 2 mm in height and the “polymeric patterns” as “honeycombs” of ～ 4–6 mm diameter with a clearly defined boundary in the form of the “swell” as high as 100 μm. The structure and composition of the materials and their growth kinetics have been investigated.     

Giant Polyoxoniobate-Based Inorganic Molecular Tweezers: Metal Recognitions,Ion-Exchange Interactions and Mechanism Studies

This work reports the interesting and unique cation-exchange behaviors of the first indium-bridged purely inorganic 3D framework based on high-nuclearity polyoxoniobates as building units. Each nanoscale polyoxoniobate features a fascinating near-icosahedral core–shell structure with six pairs of unique inorganic “molecular tweezers” that have changeable openings for binding different metal cations via ion-exchanges and exhibit unusual selective metal-uptake behaviors. Further, the material has high chemical stability so that can undergo single-crystal-to-single-crystal metal-exchange processes to produce a dozen new crystals with high crystallinity. Based on these crystals and time-dependent metal-exchange experiments, we can visually reveal the detailed metal-exchange interactions and mechanisms of the material at the atomic precision level. This work demonstrates a rare systematic and atomic-level study on the ion-exchange properties of nanoclusters, which is of significance for the exploration of cluster-based ion-exchange materials that are still to be developed.     

Layered intercalated functional materials based on efficient utilization of magnesium resources in China

Mg-based layered intercalated functional materials of the layered double hydroxide type are a significant class of magnesium compounds. Based on long-term studies of these materials in the State Key Laboratory of Chemical Resource Engineering in Beijing University of Chemical Technology, two principles of “using the intended application of a material as a guide to its structure design and synthesis process” and “the design of controlled intercalation processes in the light of future production processing requirements” have been developed. To achieve these objectives, the composition of the host layers and guest interlayer anions was tailored at the microlevel, while the mesostructure and macrostructure were controlled to fabricate different kinds of Mg-based layered intercalated functional materials. These materials have diverse applications in key areas such as catalysis, the environment, and construction, and as polymer additives. Therefore, China’s magnesium resources may be utilized more efficiently for the benefit of society.     

Functional Roles of Polymers in Room-Temperature Phosphorescent Materials: Modulation of Intersystem Crossing,Air Sensitivity and Biological Activity

Organic room-temperature phosphorescent (RTP) materials routinely incorporate polymeric components, which usually act as non-functional or “inert” media to protect excited-state phosphors from thermal and collisional quenching, but are lesser explored for other influences. Here, we report some exemplary “active roles” of polymer matrices played in organic RTP materials, including: 1) color modulation of total delayed emissions via balancing the population ratio between thermally-activated delayed fluorescence (TADF) and RTP due to dielectric-dependent intersystem crossing; 2) altered air sensitivity of RTP materials by generating various surface morphologies such as nano-sized granules; 3) enhanced bacterial elimination for enhanced electrostatic interactions with negatively charged bio-membranes. These active roles demonstrated that the vast library of polymeric structures and functionalities can be married to organic phosphors to broaden new application horizons for RTP materials.     

Chemical methods for the determination of the “oxidizing (or reducing) power” of certain materials containing a multivalent element in several oxidation states

General chemical methods for determining the “oxidizing (or reducing) power” of certain materials containing a multivalent clement in several oxidation states have beon considered. These determinations are important as representing the charge carrier concentration.The general methods available are listed and the criteria for selecting the best method for a particular material are considered. Experimental procedures and estimates of the accuracy and precision of eight methods for the determination of the “oxidizing power” and the “reducing power” are given. The application of these methods to thermoelectric materials is also described.     

Off-on/On-off Dual-Mode Hydrochromic Materials：Water-Induced Acidity Changes in the Microenvironment Regulate the Color Switching of Rhodamine Derivatives北大核心CSCD

Based on the phenomenon that rhodamine derivatives（4-N-acrylamide-（3',6'-bis（diethylamino）-spiro［isobenzofuran-1,9'-xanthene］-3-one）（AM-RhB）will open the lactone ring to display color or emit fluorescence under moderate acidic conditions（4. 425%） and fluorescence intensity modulation（>700） before and after stimulating with water,and good reversibility （> 5 times）. This work will provide a promising way for the development of new hydrochromic materials. © 2022, Science Press (China). All rights reserved.     

Hydrogels from Amorphous Calcium Carbonate and Polyacrylic Acid: Bio‐Inspired Materials for “Mineral Plastics”

Given increasing environmental issues due to the large usage of non‐biodegradable plastics based on petroleum, new plastic materials, which are economic, environmentally friendly, and recyclable are in high demand. One feasible strategy is the bio‐inspired synthesis of mineral‐based hybrid materials. Herein we report a facile route for an amorphous CaCO₃ (ACC)‐based hydrogel consisting of very small ACC nanoparticles physically cross‐linked by poly(acrylic acid). The hydrogel is shapeable, stretchable, and self‐healable. Upon drying, the hydrogel forms free‐standing, rigid, and transparent objects with remarkable mechanical performance. By swelling in water, the material can completely recover the initial hydrogel state. As a matrix, thermochromism can also be easily introduced. The present hybrid hydrogel may represent a new class of plastic materials, the “mineral plastics”.