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1.
软体家具是室内陈设的重要组成部分,它在人们生活环境中扮演着举足轻重的角色,它是否环保、健康和安全成为消费者在选购家具时的重要考虑因素。本文对软体家具常见的生物危害进行了阐述,并对国内常用的防止及检测方法进行了分析和研究。  相似文献   

2.
流化床(FBC)燃煤固硫灰渣研究综述   总被引:3,自引:0,他引:3  
结合国内外研究成果,系统总结了流化床燃煤灰渣的化学组成、物理特性和水化特性,并探讨了其资源化利用方式。目前的研究结果显示,未经处理的流化床燃煤灰渣很难直接用于水泥混凝土工程。  相似文献   

3.
本文就金属Si对硅线石结合碳化硅材料的基质结构以及对材料性能的影响进行了研究,结果表明,金属Si可显著提高该种材料的强度、密度以及抗热震性能。  相似文献   

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Background: Cardiomyopathies are a heterogeneous group of pathologies characterized by structural and functional alterations of the heart. Aims: The purpose of this narrative review is to focus on the most important cardiomyopathies and their epidemiology, diagnosis, and management. Methods: Clinical trials were identified by Pubmed until 30 March 2021. The search keywords were “cardiomyopathies, sudden cardiac arrest, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy, arrhythmogenic cardiomyopathy (ARCV), takotsubo syndrome”. Results: Hypertrophic cardiomyopathy (HCM) is the most common primary cardiomyopathy, with a prevalence of 1:500 persons. Dilated cardiomyopathy (DCM) has a prevalence of 1:2500 and is the leading indication for heart transplantation. Restrictive cardiomyopathy (RCM) is the least common of the major cardiomyopathies, representing 2% to 5% of cases. Arrhythmogenic cardiomyopathy (ARCV) is a pathology characterized by the substitution of the myocardium by fibrofatty tissue. Takotsubo cardiomyopathy is defined as an abrupt onset of left ventricular dysfunction in response to severe emotional or physiologic stress. Conclusion: In particular, it has been reported that HCM is the most important cause of sudden death on the athletic field in the United States. It is needless to say how important it is to know which changes in the heart due to physical activity are normal, and when they are pathological.  相似文献   

6.
Awoyera  Paul  Adesina  Adeyemi 《SILICON》2020,12(4):987-996
Silicon - Despite the advances in studies utilizing industrial, construction and agricultural wastes as alternative materials for concrete making, there are still gaps to be covered on the...  相似文献   

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Abstract

Rheological behaviour of rubbers (natural (NR), nitrile (NBR) and polychloroprene (CR)) and short silk fiber filled rubber compounds have been studied. The shear viscosity-shear rate relationship of both non-fiber filled and short fiber filled rubber compounds obey power law model for fluids and is similar to that of short fiber filled polymer melts. The effect of fiber concentration on the shear viscosity is more pronounced at lower shear rates. Both extrudate deformation and die swell become less on the addition of fibers to the mixes and the improvement is more significant at higher fiber concentrations. Extent of fiber breakage by the shear force during mixing is severe and is similar for all the rubbers.  相似文献   

10.
Awoyera  Paul  Adesina  Adeyemi 《SILICON》2020,12(6):1511-1511
Silicon - The original version of this paper was unfortunately published as a book review, when it is a review article.  相似文献   

11.
Since the turn of the millennium, giant magnetoelectric (ME) effects have been found in laminated composites of piezoelectric and magnetostrictive layers. Compared with ME single phase and two-phase particulate composites, laminated composites have much higher ME coefficients and are also readily fabricated. Here, we will overview the brief history of ME laminates, discussing some of the important advancements in material couples, laminate configurations, and operational modes that have allowed for dramatic enhancements in the ME voltage and charge coefficients.  相似文献   

12.
The properties of a polymer surface can be decisive for the function of the polymer. Both in the assessment of existing polymer systems and the development of new ones the possiblity of characterizing the chemical composition and structure of the polymer surface becomes important. Various instruments and chemical methods used to characterize polymer surfaces and interfaces are reviewed. The pros and cons of electron spectroscopy for chemical analysis and derivatization schemes to enhance the detectability of functional groups, Fourier transform infrared spectroscopic methods (ATR, RIFT, PAS, micro), Raman spectroscopy, static secondary ion mass spectrometry, high resolution solid state nuclear magnetic resonance, microscopy and contact angle measurements are presented. The importance of the fact that the polymer surface can undergo comparatively rapid reorientations leading to a changed surface chemistry is discussed and exemplified.  相似文献   

13.
《分离科学与技术》2012,47(8):1667-1700
Abstract

This work presents an overview of literature relative to the modelling of cake filtration and expression. Different approaches are compared to the so called conventional one in order to underline particular analogies and differences. In this way the derivation of fundamental equations (continuity equation and momentum balance) and the determination of the constitutive equations are discussed. Application of current models to complex materials such as sludge and pulp, and to simulation and design of industrial devices is also discussed.  相似文献   

14.
Combustion behaviours of melt‐castable explosives from azetidine family, 1,3,3‐trinitroazetidine (TNAZ), 3‐azido‐1‐nitroazetidine (AZNAZ) and 3‐azido‐1,3‐dinitroazetidine (AZDNAZ) have been studied. Burning rate measurements have been performed in a constant‐pressure bomb in the pressure range of 0.1–30 MPa. A pressure interval has been found within which pressed AZNAZ samples were incapable of sustained burning. Temperature profiles in the combustion wave of TNAZ, AZDNAZ and AZNAZ were measured using thin tungsten–rhenium thermocouples. Thermocouple‐aided measurements allowed the determination of the temperature dependence of TNAZ and AZDNAZ vapour pressure in a wide temperature interval, the boiling points at atmospheric pressure and the heat of evaporation. Combustion mechanisms of the energetic materials studied are discussed.  相似文献   

15.
张云  葛骞 《当代化工》2018,(3):600-602,606
注塑制品在工程塑料中占有重要地位,其中薄壁注塑制品则是注塑制品下一项重要分类。薄壁注塑聚丙烯因零件重量低、生产规模小、材料支出少和成型周期短等优点,在近些年备受关注。由于目前我国市场依旧充斥大量低端聚丙烯,高端聚丙烯却主要依赖进口,所以国内各大聚烯烃生产商陆续开发了薄壁注塑聚丙烯的自主牌号。从薄壁注塑聚丙烯的定义、特性和供需现状三个方面进行了综述。  相似文献   

16.
Platelets play a major role in hemostasis as ppwell as in many other physiological and pathological processes. Accordingly, production of about 1011 platelet per day as well as appropriate survival and functions are life essential events. Inherited platelet disorders (IPDs), affecting either platelet count or platelet functions, comprise a heterogenous group of about sixty rare diseases caused by molecular anomalies in many culprit genes. Their clinical relevance is highly variable according to the specific disease and even within the same type, ranging from almost negligible to life-threatening. Mucocutaneous bleeding diathesis (epistaxis, gum bleeding, purpura, menorrhagia), but also multisystemic disorders and/or malignancy comprise the clinical spectrum of IPDs. The early and accurate diagnosis of IPDs and a close patient medical follow-up is of great importance. A genotype–phenotype relationship in many IPDs makes a molecular diagnosis especially relevant to proper clinical management. Genetic diagnosis of IPDs has been greatly facilitated by the introduction of high throughput sequencing (HTS) techniques into mainstream investigation practice in these diseases. However, there are still unsolved ethical concerns on general genetic investigations. Patients should be informed and comprehend the potential implications of their genetic analysis. Unlike the progress in diagnosis, there have been no major advances in the clinical management of IPDs. Educational and preventive measures, few hemostatic drugs, platelet transfusions, thrombopoietin receptor agonists, and in life-threatening IPDs, allogeneic hematopoietic stem cell transplantation are therapeutic possibilities. Gene therapy may be a future option. Regular follow-up by a specialized hematology service with multidisciplinary support especially for syndromic IPDs is mandatory.  相似文献   

17.
Poly(2-hydroxyethyl methacrylate) (pHEMA) as a biomaterial with excellent biocompatibility and cytocompatibility elicits a minimal immunological response from host tissue making it desirable for different biomedical applications. This article seeks to provide an in-depth overview of the properties and biomedical applications of pHEMA for bone tissue regeneration, wound healing, cancer therapy (stimuli and non-stimuli responsive systems), and ophthalmic applications (contact lenses and ocular drug delivery). As this polymer has been widely applied in ophthalmic applications, a specific consideration has been devoted to this field. Pure pHEMA does not possess antimicrobial properties and the site where the biomedical device is employed may be susceptible to microbial infections. Therefore, antimicrobial strategies such as the use of silver nanoparticles, antibiotics, and antimicrobial agents can be utilized to protect against infections. Therefore, the antimicrobial strategies besides the drug delivery applications of pHEMA were covered. With continuous research and advancement in science and technology, the outlook of pHEMA is promising as it will most certainly be utilized in more biomedical applications in the near future. The aim of this review was to bring together state-of-the-art research on pHEMA and their applications.  相似文献   

18.
Marine biofouling of ship hulls has significant cost, performance and environmental implications. Due to environmental concerns associated with traditional antifouling paints that mitigate fouling with the use of biocides, increasing research and development efforts have been made on fouling-release (FR) coatings. FR coatings do not actively deter settlement of marine organisms, but, instead, mitigate biofouling by minimizing the strength of adhesion. Ideally, an FR coating will allow the fouling community to be removed by simply running the vessel at relatively high speed. Traditional methods for characterizing FR properties involve immersion of relatively large samples in the ocean and waiting months for enough fouling to occur to enable reliable measurements to be made. To greatly enhance research and development relative to FR coatings, a combinatorial/high-throughput workflow was developed that includes a suite of FR laboratory assays involving marine bacteria, microalgae, and live, adult barnacles. The novel high-throughput FR measurement systems have been shown to allow for rapid screening of FR characteristics of miniaturized coating samples arranged in an array format.  相似文献   

19.
The fire standard for aircraft interior panels has been compared to the corresponding marine standard with respect to smoke emission and heat release rate. This has been performed by testing an aircraft panel approved by the Federal Aviation Administration according to one of the International Maritime Organization standards for High-Speed Craft, according to the full-scale room fire test, ISO 9705. The test showed that even if the panel met the strict requirements of the Federal Aviation Administration it did not fulfil the apparently even stricter requirements of the International Maritime Organization. The panel failed on several accounts, including smoke production, heat release and structural integrity. © 1997 John Wiley & Sons, Ltd.  相似文献   

20.
The nucleophilic addition of carbon nucleophiles to amides has traditionally been a difficult task, both due to reactivity and selectivity problems. When successful, these processes would represent straightforward routes towards carbonyl‐type or amine compounds, depending on the fate of the generated tetrahedral intermediate. The direct addition of nucleophiles to amides for the preparation of ketones has been studied and applied to the syntheses of several natural products. On the other hand, the addition of nucleophiles to amides to obtain substituted amines represented a major challenge, and only scattered applications on particular substrates have appeared. Initial improvements were based on the activation of amides by introduction of particular substituents, such as in N‐methoxy amides (Weinreb amides) or electron‐withdrawing groups able to increase the carbon nucleophilicity. Although these strategies facilitate the introduction of nucleophiles, chemoselectivity issues arise when additional electrophilic moieties (i.e., carbonyls) are present, thus decreasing the versatility of the methods. In recent years, important advancements towards fully chemoselective methods have been realized. The capture of tetrahedral intermediates with acids generates highly electrophilic iminium species able to undergo chemoselective additions of various nucleophiles, thus accessing substituted amines. Alternatively, the in situ generation of an iminium triflate ion allows highly chemoselective additions of nucleophiles, yielding amines, ketones or ketimines. Also thioamides can be used as precursors of ketones or α‐substituted amines. The success of the above methodologies is further showcased by the application in various syntheses of natural products or biologically active molecules.

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