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低m(Cr)/m(Fe)铬铁矿除铁工艺的实验研究 被引量:4
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作者 赵青 张波 +1 位作者 刘承军 姜茂发 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2015年第1期47-51,共5页
以南非铬铁矿为对象,在热力学分析的基础上,采用碳热还原法开展了低m(Cr)/m(Fe)铬铁矿除铁工艺的实验研究.结果表明:实验中铬铁矿选择性除铁的适宜温度为1 100℃左右,符合热力学计算结果.低于此温度时还原出的富铁相与基体分离不彻底,... 以南非铬铁矿为对象,在热力学分析的基础上,采用碳热还原法开展了低m(Cr)/m(Fe)铬铁矿除铁工艺的实验研究.结果表明:实验中铬铁矿选择性除铁的适宜温度为1 100℃左右,符合热力学计算结果.低于此温度时还原出的富铁相与基体分离不彻底,难以结瘤析出;高于此温度时尖晶石相中的铬元素还原严重,影响铬的回收率.在1 100℃还原0.5 h并经酸浸处理后,铬铁矿可由化工级提升至冶金级,在相同温度下还原2 h后,m(Cr)/m(Fe)可由1.7提高至5.8,为实现低m(Cr)/m(Fe)铬铁矿的高效利用提供了新思路. 展开更多
关键词 铬铁矿 Cr与Fe质量比 除铁 碳热还原 尖晶石
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混合办公废纸回用中溶胶物成分及浓度变化 被引量:2
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作者 张春辉 秦梦华 +2 位作者 詹怀宇 Holmbom B 徐春林 《中华纸业》 CAS 北大核心 2006年第4期44-46,共3页
研究了溶解和胶体物质在整个混合办公废纸回用过程中的变化情况。碎浆段的DCS浓度最高,经过浮选以后DCS各参数变化不大,洗涤后各参数值大幅下降,总糖基、RFA的浓度分别约为碎浆段的10%和36%。经过过氧化氢漂白后,总糖基、RFA的浓度分别... 研究了溶解和胶体物质在整个混合办公废纸回用过程中的变化情况。碎浆段的DCS浓度最高,经过浮选以后DCS各参数变化不大,洗涤后各参数值大幅下降,总糖基、RFA的浓度分别约为碎浆段的10%和36%。经过过氧化氢漂白后,总糖基、RFA的浓度分别约为碎浆段的50%、26%。在宏观上表现为,碎浆段DCS的CODCr值、TOC值和浊度值明显高于洗涤段和漂白段,而与浮选段没有明显的差别。 展开更多
关键词 混合办公废纸 溶解与胶体物质 胶粘物
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废新闻纸碎浆后产生的溶解及胶体物质的分析
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作者 董翠华 秦梦华 +2 位作者 徐清华 徐春林 Bjarne Holmbom 《湖南造纸》 2005年第3期16-18,20,共4页
对废新闻纸碎浆过程中产生的溶解及胶体物质(DCS)进行了定性与定量分析,研究结果发现溶解物质(DS)的含量占整个DCS含量的90%左右,而胶体物质(CS)的含量仅占10%左右。另外,DCS中碳水化合物的含量明显高于亲脂性抽出物与合成聚合物,而合... 对废新闻纸碎浆过程中产生的溶解及胶体物质(DCS)进行了定性与定量分析,研究结果发现溶解物质(DS)的含量占整个DCS含量的90%左右,而胶体物质(CS)的含量仅占10%左右。另外,DCS中碳水化合物的含量明显高于亲脂性抽出物与合成聚合物,而合成聚合物的含量相对比较低。碎浆过程中释放出最多的糖类是木聚糖,仅有少量的聚半乳糖醛酸释放到体系中。在总的脂肪酸与树脂酸(RFA)中脱氢枞酸含量占整个RFA含量的一半以上,另外一种含量比较高的便是枞酸. 展开更多
关键词 DCS 碳水化合物 树脂酸 脂肪酸 胶体物质 溶解物质 废新闻纸 碎浆 合成聚合物 酸含量
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A Research-Based Teacher Education in Finland --A Dilemma for the Students 被引量:4
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作者 Gunilla Eklund 《Psychology Research》 2014年第7期567-578,共12页
关键词 教师教育 学生 基础 芬兰 科学论文 数据收集 教育机构 实用工具
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Phenotypic plasticity of labile traits in the wild 被引量:1
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作者 Jon E. BROMMER 《Current Zoology》 SCIE CAS CSCD 2013年第4期485-505,共21页
Individual-based studies allow quantification ofphenotypic plasticity in behavioural, life-history and other labile traits The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives ... Individual-based studies allow quantification ofphenotypic plasticity in behavioural, life-history and other labile traits The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically sig- nificant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individ- ual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild popula- tions, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that 'scale up' to population level proce-sses and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated 展开更多
关键词 Individual-level plasticity Life history Animal personality Linear mixed model Animal model Wild population Longitudinal study
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Characterization of modified mesoporous silica nanoparticles as vectors for siRNA delivery 被引量:2
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作者 Anna Slita Anna Egorova +2 位作者 Eudald Casals Anton Kiselev Jessica M.Rosenholm 《Asian Journal of Pharmaceutical Sciences》 SCIE 2018年第6期592-599,共8页
Gene therapy using siRNA molecules is nowadays considered as a promising approach. For successful therapy, development of a stable and reliable vector for siRNA is crucial. Non-viral and non-organic vectors like mesop... Gene therapy using siRNA molecules is nowadays considered as a promising approach. For successful therapy, development of a stable and reliable vector for siRNA is crucial. Non-viral and non-organic vectors like mesoporous silica nanoparticles(MSN) are associated with lack of most viral vector drawbacks, such as toxicity, immunogenicity, but also generally a low nucleic acid carrying capacity. To overcome this hurdle, we here modified the pore walls of MSNs with surface-hyperbranching polymerized poly(ethyleneimine)(hbPEI), which provides an abundance of amino-groups for loading of a larger amount of siRNA molecules via electrostatic adsorption. After loading, the particles were covered with a second layer of pre-polymerized PEI to provide better protection of siRNA inside the pores, more effective cellular uptake and endosomal escape. To test the transfection efficiency of PEI covered si RNA/MSNs, MDA-MB 231 breast cancer cells stably expressing GFP were used. We demonstrate that PEI-coated si RNA/MSN complexes provide more effective delivery of si RNAs compared to unmodified MSNs. Thus, it can be concluded that appropriately surface-modified MSNs can be considered as prospective vectors for therapeutic siRNA delivery. 展开更多
关键词 Gene therapy NANOCARRIERS siRNA delivery Mesoporous silica nanoparticles
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Comparable Characterization of Nanocellulose Extracted from BleachedSoftwood and Hardwood Pulps 被引量:7
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作者 Bin Li WenYang Xu +4 位作者 Dennis Kronlund Jan-Erik Eriksson Anni Maattanen Stefan Willfor ChunLin Xu 《Paper And Biomaterials》 2018年第4期35-44,共10页
In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microsco... In this study, the characteristics of nanocellulose extracted from bleached softwood and hardwood pulps by formic acid hydrolysis followed by TEMPO-mediated oxidation were compared using transmission electron microscopy(TEM), atomic force microscopy(AFM), Fourier transform infrared analysis(FT-IR), X-ray diffraction(XRD), and thermal gravimetric analysis(TGA). The experimental results showed that the nanocellulose products derived from spruce pulp exhibited a relatively larger particle size, higher crystallinity, and higher thermal stability, compared with the corresponding products obtained from aspen pulp under the same conditions.Furthermore, the study helped establish that the properties of the nanocellulose products were highly dependent on the nature of the starting materials under identical processing conditions. 展开更多
关键词 NANOCELLULOSE cellulose nanocrystal cellulose nanofbril formic acid TEMPO-mediated oxidation COMPARISON
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Size engineering of 2D MOF nanosheets for enhanced photodynamic antimicrobial therapy 被引量:2
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作者 Baoli Xue Xiwen Geng +8 位作者 Haohao Cui Huiying Chen Zhikang Wu Hong Chen Hai Li Zhan Zhou Meiting Zhao Chaoliang Tan Jingguo Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第9期219-224,共6页
Although porphyrin-based metal-organic frameworks(MOFs)have been widely explored as photosensitizers for photodynamic therapy,how the size will affect the light-induced catalytic activity for generation of reactive ox... Although porphyrin-based metal-organic frameworks(MOFs)have been widely explored as photosensitizers for photodynamic therapy,how the size will affect the light-induced catalytic activity for generation of reactive oxygen species(ROS)still remain unclear.Herein,we first report the size-controlled synthesis of two-dimensional(2D)porphyrin-based PCN-134 MOF nanosheets by a two-step solvothermal method to explore the size effect on its PDT performance,thus yielding enhanced photodynamic antimicrobial therapy.By simply controlling the reaction temperature in the synthesis process,the bulk PCN-134 crystal,large PCN-134(L-PCN-134)nanosheets with a lateral size of 2–3μm and thickness of 33.2–37.5 nm and small PCN-134 nanosheets(S-PCN-134)with a lateral size of 160–180 nm and thickness of 9.1–9.7 nm were successfully prepared.Interestingly,the S-PCN-134 nanosheets exhibit much higher photodynamic activity for ROS generation than that of the bulk 3D PCN-134 crystal and L-PCN-134 nanosheets under a660 nm laser irradiation,suggesting that the photodynamic activity of PCN-134 MOF increases when the size reduces.Therefore,the S-PCN-134 nanosheets show much enhanced performance when used as a photosensitizer for photodynamic antimicrobial activity and wound healing. 展开更多
关键词 2D nanosheets PCN-134 MOFs Size effect Photodynamic therapy ANTIBACTERIAL
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铜版纸胶印油墨组分的可视化分析 被引量:1
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作者 H. Koivula J.S. Preston +1 位作者 EJ. Heard M. Toivakka 《中国印刷与包装研究》 CAS 2009年第1期111-112,共2页
近年来,人们在纸张吸墨性与印品密度的关系方面进行了广泛的研究。本文将一系列热固型油墨的各组分分别印刷到铜版纸上,利用聚焦离子束(FIB)观察各组分的分布情况。然后利用同样的方法,观察成品油墨印刷时各组分的分布情况。油墨光油也... 近年来,人们在纸张吸墨性与印品密度的关系方面进行了广泛的研究。本文将一系列热固型油墨的各组分分别印刷到铜版纸上,利用聚焦离子束(FIB)观察各组分的分布情况。然后利用同样的方法,观察成品油墨印刷时各组分的分布情况。油墨光油也适用于改良的薄层色谱(TLC)板,这些薄板与纸张涂有相同的涂层。TLC板上分离的油墨组分可以使用红外光谱来测定。实验结果表明,聚焦离子束可对进入涂料层的油墨组分进行观察,但是矿物油例外。由于其具有挥发性,在干燥后和真空环境内不能留在纸张涂层内,同时注意到当蜡溶解在油里的样品同样要求在涂层的孔隙结构有一个非常清晰的成像时,FIB图像的差异显著增加。这项研究与其他已知研究结果一致,即颜料和硬树脂留在涂层的表面,而矿物油和植物油迅速渗透进入涂层。酯类溶剂和溶解蜡同样渗入涂层。 展开更多
关键词 聚焦离子束 改良薄层色谱法 油墨固化 铜版纸 可视化分析
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Ionic Liquid Assisted Extraction of Nitrogen and Sulphur-Containing Air Pollutants from Model Oil and Regeneration of the Spent Ionic Liquid 被引量:5
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作者 Ikenna Anugwom Paivi Maki-Arvela +1 位作者 Tapio Salmi Jyri-Pekka Mikkola 《Journal of Environmental Protection》 2011年第6期796-802,共7页
Removal of air pollutants, such as nitrogen and sulphur containing compounds from a model oil (dodecane) was studied. An ionic liquid (1-ethyl-3-methylimidazolium chloride [C2mim] [Cl]) was used as an extractant. Liqu... Removal of air pollutants, such as nitrogen and sulphur containing compounds from a model oil (dodecane) was studied. An ionic liquid (1-ethyl-3-methylimidazolium chloride [C2mim] [Cl]) was used as an extractant. Liquid-liquid extraction by using 1-ethyl-3-methylimidazolium chloride [C2mim] [Cl] was found to be a very promising method for the removal of N- and S-compounds. This was evaluated by using a model oil (dodecane) with indole as a neutral nitrogen compound and pyridine as a basic nitrogen compound. Dibenzothiophene (DBT) was used as a sulphur compound. An extraction capacity of up to 90 wt% was achieved for the model oil containing pyridine, while only 76 wt% of indole in the oil was extracted. The extraction capacity of a model sulphur compound DBT was found to be up to 99 wt%. Regeneration of the spent ionic liquid was carried out with toluene back-extraction. A 1:1 toluene-to-IL wt ratio was performed at room temperature. It was observed that, for the spent ionic liquid containing DBT as a model compound more than 85 wt% (corresponding 3852 mg/kg) could be removed from the oil. After the second regeneration cycle, 86 wt% of the DBT was recovered from the ionic liquid to toluene. In the case of indole as the nitrogen containing species, more than 99 wt%, (corresponding to 2993 mg/kg) of the original indole was transferred from the model oil to the ionic liquid. After the first-regeneration cycle of the spent ionic liquid, 54 wt% of the indole–in-IL was transferred to toluene. Thus, both extractions of nitrogen and sulphur model compounds were successfully carried out from model oil and the back-extraction of these compounds from the ionic liquids to toluene demonstrated the proved the concept of the regeneration point of view. 展开更多
关键词 Ionic Liquids Extraction Air Pollutants Nitrogen Compound Sulfur Compounds
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Radiative Cooling in Northern Europe Using a Skylight 被引量:1
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作者 M. Falt R. Zevenhoven 《Journal of Energy and Power Engineering》 2011年第8期692-702,共11页
The purpose of this paper is to present the design and performance of a skylight using a mathematical model. This model uses weather data from the Finnish city Helsinki to assess its performance. This skylight could a... The purpose of this paper is to present the design and performance of a skylight using a mathematical model. This model uses weather data from the Finnish city Helsinki to assess its performance. This skylight could act as a radiative cooler or as a thermal insulator depending on the need. This versatile usage would thus decrease the need for traditional air-conditioning and hence save electricity. The skylight would consist of one normal silica glass window and of two polymer windows with a grcenhousc gas trapped in the spaces between the windows. The skylight would be in its cooling mode when the two spaces would be connected to each other and insulating when disconnected. Thus when cooling, a natural convective flow transports heat from the 1o~ er part of the skylight to the upper part of the skylight where the greenhouse gas is cooled by radiative heat exchange with the sky. 展开更多
关键词 Radiative cooling SKYLIGHT heat radiation in participating media resistance network
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人类活动导致变化的内海:波罗的海与黑海之间的比较 被引量:1
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作者 Erkki Leppkoski Pia Elena Mihnea 张康生 《人类环境杂志》 1996年第6期380-388,407,共10页
本评论首次试图根据环境观点对波罗的海和黑海进行比较。这两个海都受到人类活动导致的变化的影响,并受到日益增加的富营养化和环境退化的严重威胁。这两个海都因物理屏障和生态屏障而与大洋隔绝。在冰期之后,这两个海都曾是淡水湖,如... 本评论首次试图根据环境观点对波罗的海和黑海进行比较。这两个海都受到人类活动导致的变化的影响,并受到日益增加的富营养化和环境退化的严重威胁。这两个海都因物理屏障和生态屏障而与大洋隔绝。在冰期之后,这两个海都曾是淡水湖,如今它们都显示出成层条件。过去几十年内的这些变化可能与下列因素相关:污染、集水区内的大规模变化、生境退化、生物资源的过度开发和生物地理事件(新物种的建立和本地生物的灭绝)。我们提供了对初级生产、浮游植物、浮游动物、大型植物群落、大型底栖动物种群和鱼类群落中多源压力的反应之实例。从局部、地区和整个海盆尺度论述了这两个海的生态系统病理学症状及其应付压力的机制。 展开更多
关键词 海洋学 波罗的海 黑海
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An Overview of Advanced Chalcogenide Thermoelectric Materials and Their Applications 被引量:1
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作者 Fiseha Tesfaye Mykola Moroz 《Journal of Electronic Research and Application》 2018年第2期28-41,共14页
Thermoelectricity is a strong scientific and technological interest due to its wide application ranging from clean energy producing to photon sensing devices.Recent developments in theoretical studies on the thermoele... Thermoelectricity is a strong scientific and technological interest due to its wide application ranging from clean energy producing to photon sensing devices.Recent developments in theoretical studies on the thermoelectric(TE)effects as well as the newly discovered thermoelectric materials provide new opportunities for several applications.Though the scale of production is limited,thermoelectric technology provides an alternative to traditional methods of power generation,heating and cooling systems.TE technologies can be used in power generation,heating and cooling applications.They potentially offer significant energy savings through waste heat recovery and augmented cooling.This article critically discusses the current progress in chalcogenide TE materials and the advantages and limitations associated with the TE technologies.The need for new materials discoveries from the point of view of achieving higher figure-of-merit combined with thermal stabilities in intermediate-and hightemperature Peltier and Seebeck effects applications is also emphasized.Besides,this article aims to evaluate the main features of recently characterized multicomponent chalcogenide ionic compounds with high thermal stabilities as potential TE materials to harvest electric power from high-temperature heat flux via thermoelectricity. 展开更多
关键词 Thermoelectric materials CONDUCTIVITY thermal stability renewable energy
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Developments in Humidity Standards and the Psychrometer Equation
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作者 Ian C.Kemp Carl-Gustav Berg 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第6期792-800,共9页
Determination of the wet-bulb temperature at the surface of a material is the basis of one class ofhumidity measuring instruments, and is important in industrial applications such as dryer modelling and simula-tion. T... Determination of the wet-bulb temperature at the surface of a material is the basis of one class ofhumidity measuring instruments, and is important in industrial applications such as dryer modelling and simula-tion. The psychrometer equation is a frequently used method of estimating wet-bulb temperature, and contains apsychrometer 'constant'. Analysis shows that this is in fact a variable coefficient affected by temperature, pressure,radiation and conduction effects, and the identity of the gas and vapour. Radiation and conduction affect the dif-ference between adiabatic saturation temperature and indicated wet-bulb temperature. Inconsistencies in currentlyrecommended values for the psychrometer coefficient, including published international standards, are identifiedand explained. Particular problems arise when the enhancement factor is applied to vapour pressure to accountfor non-ideality of gases. Special considerations are also needed for wet-bulb temperatures approaching the boilingpoint, where the psychrometer coefficient tends to zero. Self-consistent recommendations recently published in thenew British Standard BS1339 are given, which cover both the air-water system and a general vapour-gas system. 展开更多
关键词 psychrometry humidity STANDARDS CONVECTION DIFFUSION enhancement factor
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ELASTICITY OF MONOLAYER OF LINOLEIC ACID AND ITS POLYMER
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作者 何平笙 PELTONEN J.P.K. ROSENHOLM J.B. 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1998年第2期147-154,共8页
The dynamic elasticity of linoleic acid monolayer on a subphase of 10** minus **4mol/L TbCl//3 at various surface pressure has been measured by means of dynamic oscillation method in measuring the change of surface pr... The dynamic elasticity of linoleic acid monolayer on a subphase of 10** minus **4mol/L TbCl//3 at various surface pressure has been measured by means of dynamic oscillation method in measuring the change of surface pressure caused by periodic compression-expansion cycles of the barrier. The elasticity of monolayer increases with increasing of surface pressure linearly. The linoleic acid polymer monolayer has been obtained under UV-irradiation in situ when keeping a constant surface pressure. But the elasticity of the resulting polymerized monolayer is even smaller than that of its corresponding monomer monolayer. The elasticity of the polymerized linoleic acid monolayer decreases with increasing polymerization time. The explanation based on entropy has been presented. (Author abstract) 10 Refs. 展开更多
关键词 ELASTICITY MONOLAYER linoleic acid
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THE BLOCH SPACE ON THE UNIT BALL OF A HILBERT SPACE: MAXIMALITY AND MULTIPLIERS
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作者 Pablo GALINDO Mikael LINDSTRÖM 《Acta Mathematica Scientia》 SCIE CSCD 2021年第3期899-906,共8页
We prove that, as in the finite dimensional case, the space of Bloch functions on the unit ball of a Hilbert space contains, under very mild conditions, any semi-Banach space of analytic functions invariant under auto... We prove that, as in the finite dimensional case, the space of Bloch functions on the unit ball of a Hilbert space contains, under very mild conditions, any semi-Banach space of analytic functions invariant under automorphisms. The multipliers for such Bloch space are characterized and some of their spectral properties are described. 展开更多
关键词 Analytic functions on Hilbert space invariance under automorphisms multiplier
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在涂布纸上喷墨印刷P3HT及其润湿性和印刷品质的研究
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作者 Anni Mttnen Petri Ihalainen +3 位作者 Roger Bollstrm Martti Toivakka Jouko Peltonen 方一 《中国印刷与包装研究》 CAS 2011年第2期67-70,共4页
近年来,低成本的纸和类纸基材已被广泛应用于各种印刷电子领域。以纸或类纸为基材,采用功能墨水(如导电聚合物、半导电聚合物和碳纳米管)可以制备诸如晶体管、电容和感应器等电子元件。目前的相关报道很多,如在报纸上印制有机光电二极... 近年来,低成本的纸和类纸基材已被广泛应用于各种印刷电子领域。以纸或类纸为基材,采用功能墨水(如导电聚合物、半导电聚合物和碳纳米管)可以制备诸如晶体管、电容和感应器等电子元件。目前的相关报道很多,如在报纸上印制有机光电二极管,在微生物纤维素膜上印制电子纸显示器,在纸基上印制可折叠热致变色显示器及在真空沉积聚对二甲苯涂层纸张上印制高性能有机薄膜晶体管阵列。 展开更多
关键词 涂布纸 印刷品 质的研究 喷墨印刷 导电聚合物 薄膜晶体管 电子元件 聚对二甲苯
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Prins cyclisation of (-)-isopulegol with benzaldehyde over ZSM-5 based micro-mesoporous catalysts for production of pharmaceuticals
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作者 Ekaterina Kholkina Paivi Maki-Arvela +3 位作者 Chloe Lozachmeuer Roman Barakov Nataliya Shcherban Dmitry Yu. Murzin 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第11期1713-1720,共8页
Several ZSM-5 derived micro-mesoporous catalysts were investigated in Prins cyclisation of (-)-isopulegol with benzaldehyde acting as a reactant and a solvent for production of heterocyclic oxygen containing 2H-chrome... Several ZSM-5 derived micro-mesoporous catalysts were investigated in Prins cyclisation of (-)-isopulegol with benzaldehyde acting as a reactant and a solvent for production of heterocyclic oxygen containing 2H-chromene derivatives including the tetrahydropyran structure and exhibiting biological activity. The investigated catalysts were characterized by nitrogen adsorption, ammonia temperature programmed desorption, adsorption-desorption of pyridine and 2,6-di-tert- butylpyridine with Fourier transform infrared spectroscopic control. For the Prins reaction performed at 70℃, the highest yield of the desired product, equal to 67% at complete conversion of (-)-isopulegol, was obtained over a micro-mesoporous catalyst containing an optimum amount of strong acid sites and mesopores, being 12 fold larger than the size of the desired product. 展开更多
关键词 Micro-mesoporous material Prins cyclisation TETRAHYDROPYRAN
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Vineyards,but not cities,are associated with lower presence of a generalist bird,the Common Blackbird(Turdus merula),in Western France
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作者 Bertille Mohring Francois Brischoux Frédéric Angelier 《Avian Research》 CSCD 2021年第1期17-27,共11页
Background:Land-use change is one of the main drivers of the global erosion of biodiversity.In that context,it is crucial to understand how landscape characteristics drive the presence of rare endangered species.Never... Background:Land-use change is one of the main drivers of the global erosion of biodiversity.In that context,it is crucial to understand how landscape characteristics drive the presence of rare endangered species.Nevertheless,it is also important to study common species in multiple habitats,because they represent a large proportion of biodiversity and are essential to maintain ecological functions.Interestingly,some habitats,as farmlands with permanent crops(e.g.vineyards),have been overlooked in the literature.Methods:In this study,we investigated the distribution of a widespread and common bird species,the Common Blackbird(Turdus merula),within and between the three main habitats of our study area(rural Western France).We specifically focused on(1)woodlands,(2)farmlands with a high vineyard coverage,and(3)moderately urbanized areas.Specifically,we aimed to assess the beneficial and detrimental effects of these habitats and their fine-scale composition on the presence of a common bird species,relying on a survey by point counts(nearly 100 locations).We studied the effects of habitats and gradients of fine-scale habitat composition on blackbird presence using logistic regression analyses.Results:Blackbirds were present in all studied habitats.However,their presence varied between habitats,being lower in vineyards than in woodlands and cities.In woodlands and cities,fine-scale analyses did not reveal any component driving the species'presence.However,we found that shrub and tree vegetation cover had a significant positive effect on blackbird presence in vineyards.Conclusions:Our results are in agreement with the definition of a generalist species.Interestingly,species distribution varied between habitats.The high presence of blackbirds in urban areas suggests that medium-sized cities,despite their artificialization,do not constrain the settlement of this former forest specialist and that green spaces may allow blackbirds to thrive in medium-sized cities.On the contrary,we found an impoverished presence of blackbirds in vineyards and a positive effect of vegetation on their presence in these landscapes.This suggests that permanent crops,and more generally farmlands,may impose important constraints to common species.Future studies should examine how to enhance biodiversity through agricultural management policies,especially in vineyards. 展开更多
关键词 Agriculture Biodiversity BIRDS Forest Turdus merula Urbanization VINEYARDS
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Freeze substitution Hi-C,a convenient and cost-effective method for capturing the natural 3D chromatin conformation from frozen samples
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作者 Wu Zheng Zhaoen Yang +11 位作者 Xiaoyang Ge Yijia Feng Ye Wang Chengwei Liu Yanan Luan Kun Cai Serhii Vakal Feng You Wei Guo Wei Wang Zhenhua Feng Fuguang Li 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2021年第3期237-247,共11页
Chromatin interactions functionally affect genome architecture and gene regulation,but to date,only fresh samples must be used in High-through chromosome conformation capture(Hi-C)to keep natural chromatin conformatio... Chromatin interactions functionally affect genome architecture and gene regulation,but to date,only fresh samples must be used in High-through chromosome conformation capture(Hi-C)to keep natural chromatin conformation intact.This requirement has impeded the advancement of 3 D genome research by limiting sample collection and storage options for researchers and severely limiting the number of samples that can be processed in a short time.Here,we develop a freeze substitution Hi-C(FS-Hi-C)technique that overcomes the need for fresh samples.FS-Hi-C can be used with samples stored in liquid nitrogen(LN2):the water in a vitreous form in the sample cells is replaced with ethanol via automated freeze substitution.After confirming that the FS step preserves the natural chromosome conformation during sample thawing,we tested the performance of FS-Hi-C with Drosophila melanogaster and Gossypium hirsutum.Beyond allowing the use of frozen samples and confirming that FS-Hi-C delivers robust data for generating contact heat maps and delineating A/B compartments and topologically associating domains,we found that FS-HiC outperforms the in situ Hi-C in terms of library quality,reproducibility,and valid interactions.Thus,FS-HiC will probably extend the application of 3D genome structure analysis to the vast number of experimental contexts in biological and medical research for which Hi-C methods have been unfeasible to date. 展开更多
关键词 FS-Hi-C Frozen sample Chromosome conformation Drosophila melanogaster Gossypium hirsutum
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