透平膨胀机及发展动态

比较了国内外常规透平膨胀机的主要技术参数 ;重点介绍了国外带液透平膨胀机、全液体透平膨胀机、能量回收用透平膨胀机和磁悬浮轴承透平膨胀机的发展动态     

青成色剂的进展

介绍了彩色相纸及负片用青成色剂的演变，包括各种类型青成色剂的优缺点、现行负片中青成色剂的作用机理、应用条件。并且对新型结构的青成色剂作了简要展望。     

Operational experience with a 10 MW diesel driven heat pump at Frederikshavn, Denmark

Test results from a 10 month running-in and operation period are presented for a 10 MW diesel driven compression type heat pump. The heat pump was delivered by Burmeister and Wain, Scandinavian Contractor A/S to the Municipality of Frederikhavn in Denmark. The COP is between 1.81 and 1.87 with an evaporation temperature at 2°C and a temperature of 85°C on the outgoing water at full load.     

Palaeoenvironmental reconstruction in the Southern Levant: synthesis, challenges, recent developments and perspectives

Palaeoenvironmental research in the Southern Levant presents a series of challenges, partly due to the unequal distribution of palaeoenvironmental records and potential archives throughout the region. Our knowledge of climatic evolution, during the last approximately 25,000 years, is of crucial importance to understand cultural developments. More local, well-dated, multi-proxy studies are much needed to obtain an accurate picture of environmental change in respect of the Late Pleistocene and the Holocene. This contribution reviews the current state of knowledge regarding Late Quaternary palaeoenvironmental changes in the Southern Levant, including some examples of more recent developments in palaeoenvironmental reconstruction in Israel and the Dead Sea area, and introduces the major challenges researchers face in the region. It also presents the first results of a new case study in Jordan, based on an analysis of peaty deposits located in the mountain slopes east of the Dead Sea. Such new studies help refine our knowledge of local environmental changes in the Southern Levant and especially the more arid areas, for which little information is presently available. More material suitable for palaeoenvironmental research, for example extensive tufa and travertine series, still awaits consideration in Jordan, opening up exciting perspectives for future research in the area.     

Electron paramagnetic resonance: recent developments and trends

Major recent advances:High-field multi-frequency EPR improves our knowledge of magnetic materials, conductive polymers, and spin systems with large zero-field splittings. High-field electron nuclear double resonance provides better access to subtle details of the electronic structure of materials. Materials structure on length scales between 1.5 and 8 nm can now be characterized more precisely.     

Heavy fermions: Typical phenomena and recent developments

A survey is given of typical phenomena, new materials and recent developments in heavy-fermion physics. In particular, the following topics are addressed: (i) YbNiAl, a new heavy-fermion local-moment antiferromagnet (LMM) with Néel temperature T_n = 3 K, (ii) non-Fermi-liquid behavior at the magnetic instability in two heavy-fermion systems with intact f-ion sublattice, i.e. orthorhombic CePt(Si_1–xGe_x) and tetragonal U(Cu_4+xAl_8–x), (iii) the low-temperature properties of the anisotropic Rondo insulator CeNiSn, and (iv) some of the most unusual observations made on low-carrier-density rare-earth systems like Sm₃Te₄ and Sm₃Se₄. While the exotic symmetry-broken (superconducting and magnetic) ground states of heavy-fermion metals are discussed in several other contributions to this volume, we focus in the remainder of this paper on the relationship between LMM ordering and heavy-fermion superconductivity: Firstly, the LMM ordered compound CeCu₂Ge₂ (T_n = 4.1K) is addressed which was recently found to become a non-magnetic heavy-fermion superconductor under high hydrostatic pressure, p 70 kbar (D. Jaccard et al., Phys. Lett. A163,475 (1992)). Point-contact spectroscopy is used to investigate in more detail the high-pressure superconducting phase of CeCu₂Ge₂. Secondly, we summarize high-pressure results on UPd₂Al₃, the first compound to show homogeneous coexistence between LMM ordering and heavy-fermion superconductivity.     

可降解聚氨酯材料发展现状与趋势

介绍了可降解聚氨酯材料的概念与意义,并按时间顺序和技术发展程度,对近年来可降解聚氨酯材料经历的与天然物质共混、改性后共混、与天然物质共聚、分子链设计等几个合成阶段的发展历程作了详细介绍,综述了降解机理及表征方法方面的研究进展,并对可降解聚氨酯材料的发展前景作了评述.     

Cyclotron 99mTc Production and Quality Control for Medical Applications

Radiochemistry - A new production method of 99mTc using a high-current solid target was tested. The separation and purification setup was developed to produce high quantity and high specific...     

Review of the recent developments in cellulose nanocomposite processing

This review addresses the recent developments of the processing of cellulose nanocomposites, focusing on the most used techniques, including solution casting, melt-processing of thermoplastic cellulose nanocomposites and resin impregnation of cellulose nanopapers using thermoset resins. Important techniques, such as partially dissolved cellulose nanocomposites, nanocomposite foams reinforced with nanocellulose, as well as long continuous fibers or filaments, are also addressed. It is shown how the research on cellulose nanocomposites has rapidly increased during the last 10 years, and manufacturing techniques have been developed from simple casting to these more sophisticated methods. To produce cellulose nanocomposites for commercial use, the processing of these materials must be developed from laboratory to industrially viable methods.     

Theory of defects in Si and Ge: Past, present and recent developments

Over the past few decades, considerable progress has been achieved in the theoretical predictions of a wide range of properties of defects in semiconductors. In addition to structures, energetics, spin and charge densities, theory now routinely predicts accurate vibrational properties of defects, and thus connects to the optical characterization of light impurities. However, the positions of gap levels have yet to be predicted with systemically reliable accuracy. Today, supercells much larger than in the past are being used to describe defect centers from first principles. Systems large enough to study the dynamics of extended defects can be handled near the first-principles level. This paper contains a brief review of the key developments that have rendered theory quantitatively useful to experimentalists and an overview of the current ‘state-of-the-art’ and ongoing developments. Some of the remaining challenges are discussed, with examples in Si and Ge.     

Introduction: recent developments in the study of gamma-ray bursts

Gamma-ray bursts (GRBs) are immensely powerful explosions, originating at cosmological distances, whose outbursts persist for durations ranging from milliseconds to tens of seconds or more. In these brief moments, the explosions radiate more energy than the Sun will release in its entire 10Gyr lifetime. Current theories attribute these phenomena to the final collapse of a massive star, or the coalescence of a binary system induced by gravity wave emission. New results from Swift and related programmes offer fresh understanding of the physics of GRBs, and of the local environments and host galaxies of burst progenitors. Bursts found at very high red shifts are new tools for exploring the intergalactic medium, the first stars and the earliest stages of galaxy formation. This Royal Society Discussion Meeting has brought together leading figures in the field, together with young researchers and students, to discuss and review the latest results from NASA's Swift Gamma-ray Burst Observatory and elsewhere, and to examine their impact on current understanding of the observed phenomena.     

Some recent developments in the theory of boundary layer instability

The online version of the original article can be found at     

Some recent developments in the theory of boundary layer instability

The stability of boundary-layer flow over a flat-plate is investigated after taking into account the effects of boundary-layer growth. A critical review and analysis of earlier work is presented, mainly for those works that use an inhomogeneous Orr-Sommerfeld equation and a solvability condition to obtain corrections for the growth-rate based on the quasi-parallel (qp) approximation. During the course of this review and analysis an important result is proven; viz., for a ray, the basic spatial periodicity of the disturbance wave is indimensional space. Thereafter the energy integral equation is invoked, and an optimal monitorable property is found that has the same growth-rate as given by the eigensolution of the associated homogeneous problem. This also leads to the optimal normalisation of the eigenfunction at different downstream stations along the plate. A surprising result found is that the past non-parallel results can be virtually totally reproduced based on theqp-approximation and using the present methodology. And, by using the present methodology for the full non-parallel problem, the results obtained are in very much better agreement with past experimental results, and with the results of Smith based on the triple-deck theory. The students and co-workers who have worked on this problem are Dr T K Vashist and Ms R Verma.     

Otic drug delivery systems: formulation principles and recent developments

Disorders of the ear severely impact the quality of life of millions of people, but the treatment of these disorders is an ongoing, but often overlooked challenge particularly in terms of formulation design and product development. The prevalence of ear disorders has spurred significant efforts to develop new therapeutic agents, but perhaps less innovation has been applied to new drug delivery systems to improve the efficacy of ear disease treatments. This review provides a brief overview of physiology, major diseases, and current therapies used via the otic route of administration. The primary focuses are on the various administration routes and their formulation principles. The article also presents recent advances in otic drug deliveries as well as potential limitations. Otic drug delivery technology will likely evolve in the next decade and more efficient or specific treatments for ear disease will arise from the development of less invasive drug delivery methods, safe and highly controlled drug delivery systems, and biotechnology targeting therapies.     

Moisture losses from perishable commodities: recent research and developments

Moisture loss from stored perishable commodities has been a subject considerable research interest in recent years, both from the standpoint of improved design of refrigerated storages and measurement of transpiration coefficients. This Paper presents a review of recent literature on the subject.     

Operational storm surge forecasting in the Netherlands: developments in the last decade

The accurate forecasting of storm surges is an important issue in the Netherlands. With the emergence of the first numerical hydrodynamic models for surge forecasting at the beginning of the 1980s, new demands and possibilities were raised. This article describes the main phases of the development and the present operational set-up of the Dutch continental shelf model, which is the main hydrodynamic model for storm surges in the Netherlands. It includes a brief discussion of applied data-assimilation techniques, such as Kalman filtering, the model calibration process and some thoughts on quality assurance in an operational environment. After further describing some select recent investigations, the paper concludes with some remarks on future developments in a European context.     

Sedimentation and suspension flows: Historical perspective and some recent developments

Sedimentation and suspension flows play an important role in modern technology. This special issue joins nine recent contributions to the mathematics of these processes. The Guest Editors provide a concise account of the contributions to research in sedimentation and thickening that were made during the 20th century with a focus on the different steps of progress that were made in understanding batch sedimentation and continuous thickening processes in mineral processing. A major breakthrough was Kynch's kinematic sedimentation theory published in 1952. Mathematically, this theory gives rise to a nonlinear first-order scalar conservation law for the local solids concentration. Extensions of this theory to continuous sedimentation, flocculent and polydisperse suspensions, vessels with varying cross-section, centrifuges and several space dimensions, as well as its current applications are reviewed.     

Selenium nanomaterials: An overview of recent developments in synthesis,properties and potential applications

Advances in science and nanotechnology have facilitated the development of new methods for the preparation of pure selenium as selenium nanomaterials. They offer remarkable potential for technological applications in the fields of medicine, diagnostics, therapeutics, toxicology, electronics, catalysis and so on. Moreover, selenium nanomaterials also find applications in photographic exposure metres, rectifiers, signal emitting devices and transmitting devices, because of their unique structural, optical and electronic properties. This study describes a detailed advanced report on the synthesis, assembly, characterization and various applications of selenium nanomaterials. In addition, relevant synthesis methods, properties, challenges and opportunities associated with selenium nanomaterials are also presented.