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Pelleting and particle size reduction of corn increase net energy and digestibility of fiber,protein,and fat in corn-soybean meal diets fed to group-housed pigs
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作者 Su A Lee Diego A.Rodriguez +1 位作者 Chad B.Paulk Hans H.Stein 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第4期1751-1760,共10页
Background Reduction of the particle size of corn increases energy digestibility and concentrations of digestible and metabolizable energy.Pelleting may also reduce particle size of grain,but it is not known if there ... Background Reduction of the particle size of corn increases energy digestibility and concentrations of digestible and metabolizable energy.Pelleting may also reduce particle size of grain,but it is not known if there are interactions between particle size reduction and pelleting.The objective of this experiment was to test the hypothesis that particle size reduction and pelleting,separately or in combination,increase N balance,apparent total tract digestibility(ATTD)of fiber and fat,and net energy(NE)in corn-soybean meal diets fed to group-housed pigs.Methods Six corn-soybean meal-based diets were used in a 3×2 factorial design with 3 particle sizes of corn(i.e.,700,500,or 300μm)and 2 diet forms(i.e.,meal or pelleted).Pigs were allowed ad libitum access to feed and water.Twenty-four castrated male pigs(initial weight:29.52 kg;standard diviation:1.40)were allotted to the 6 diets using a 6×6 Latin square design with 6 calorimeter chambers(i.e.,4 pigs/chamber)and 6 periods.Oxygen consumption and CO_(2)and CH_(4)productions were measured during fed and fasting states and fecal and urine samples were collected.Results Regardless of particle size of corn,the ATTD of gross energy(GE),N,and acid-hydrolyzed ether extract(AEE),and the concentration of NE were greater(P<0.05)in pelleted diets than in meal diets.Regardless of diet form,the ATTD of GE,N,and AEE,and the concentration of NE were increased(linear;P<0.05)by reducing the particle size of corn,but the increase was greater in meal diets than in pelleted diets(interaction;P<0.05).Conclusions Both pelleting and reduction of corn particle size increased nutrient digestibility and NE,but increases were greater in meal diets than in pelleted diets. 展开更多
关键词 CORN DIGESTIBILITY Feed technology Net energy Particle size PELLETING
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Effect of Powder Particle Size on the Properties and Microstructure of Ti(C,N)-Based Cermet 被引量:8
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作者 Yong Zheng, Weihao Xiong (Key State Laboratory of Die Technology, Huazhong University of Science and Technology, Wuhan 430074, China) 《Rare Metals》 SCIE EI CAS CSCD 2001年第1期47-51,共5页
The influence of raw powder particle size on the properties and microstructures of Ti (C, N)-based cermets has been studied. The conclusions are as follows: The microstructures of cermets were composed of two kinds of... The influence of raw powder particle size on the properties and microstructures of Ti (C, N)-based cermets has been studied. The conclusions are as follows: The microstructures of cermets were composed of two kinds of grains, the one with black cores surrounded by obvious rim structures, and the other whose cores were white with unconspicuous rim structures and adhesive phase. In the cermet made from fine powders, the amount of grains with white cores was much more than that in cermet made from coarse powders. In addition, their properties were also much better. 展开更多
关键词 Ti(C N)-based cermet powder particle size property MICROSTRUCTURE
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Study on Particle Size and Electrochemical Properties of Rare Earth Based Hydrogen Storage Alloys 被引量:1
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作者 刘向东 黄丽宏 +1 位作者 闫淑芳 陈伟东 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期363-365,共3页
The rare earth based hydrogen storage alloys Ml_ 0.7Mm_ 0.3(Ni_ 3.55Co_ 0.75Mn_ 0.4Al_ 0.3) were chosen as objects of investigation in this paper. The effects of particle size on electrochemical properties of the allo... The rare earth based hydrogen storage alloys Ml_ 0.7Mm_ 0.3(Ni_ 3.55Co_ 0.75Mn_ 0.4Al_ 0.3) were chosen as objects of investigation in this paper. The effects of particle size on electrochemical properties of the alloy were investigated. The results indicate that the alloy with particle size of 100 and 150 mesh shows good activation behavior and high discharge capacity (the first discharge capacity and the maximum discharge capacity), but poor cycling stability, low capacity retention and high discharge capacity rate. The Ml_ 0.7Mm_ 0.3(Ni_ 3.55Co_ 0.75Mn_ 0.4Al_ 0.3) alloy with particle size of 150 mesh shows excellent electrochemical properties. 展开更多
关键词 rare earth based hydrogen storage alloy particle size electrochemical property
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Potential Applications of Nano-Scale Science and Technology in Geosciences and Experimental Studies of Nanometer-Sized Gold Adsorption on Minerals and Rocks 被引量:3
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作者 章振根 朱笑青 《Chinese Journal Of Geochemistry》 EI CAS 1997年第2期133-138,共6页
Potential applications of Nano-scale science and technology are discussed in mineralogy, ore deposits, cosmochemistry and environmental sciences. Adsorption of nanometersized gold was experimentally studied on a varie... Potential applications of Nano-scale science and technology are discussed in mineralogy, ore deposits, cosmochemistry and environmental sciences. Adsorption of nanometersized gold was experimentally studied on a variety of minerals and rocks. 展开更多
关键词 纳米技术 地球科学 地球化学 纳米金 吸收 矿物 岩石
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The role of e-readiness assessment criteria in accepting e-commerce for small and medium size enterprisesmDevelopment of technology acceptance model
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作者 Nour-Mohammad Yaghoubi Roya Shakeri 《Chinese Business Review》 2010年第2期21-26,共6页
This paper develops Davis technology acceptance model by adding two criteria of e-readiness assessment. For small and medium size enterprises, the paper evaluates the credit of developed model in studying the efficien... This paper develops Davis technology acceptance model by adding two criteria of e-readiness assessment. For small and medium size enterprises, the paper evaluates the credit of developed model in studying the efficient factors in internet technology acceptance, which is one of the most applicable communication tools in e-commerce. The added factors, taken from models and means of e-readiness assessment, are "existing information technology infrastructures" as well as "organization's training". The authors study 45 small and medium size enterprises in the city of Tehran, which are active in information technology products and services. Using Lisrel structural equation modelling, it is shown that there is a meaningful relationship between the added factors and the variables indicating internet network usage. Therefore, the better factors of e-readiness assessment lead to the higher acceptance level of electronic communication tools in e-commerce. 展开更多
关键词 information technology E-READINESS E-COMMERCE technology acceptance small and medium size enterprises
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Particle Size Estimation Based on Edge Density 被引量:1
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作者 王卫星 《Journal of Electronic Science and Technology of China》 2005年第4期310-313,共4页
Given image sequences of closely packed particles, the underlying aim is to estimate diameters without explicit segmentation. In a way, this is similar to the task of counting objects without directly counting them. S... Given image sequences of closely packed particles, the underlying aim is to estimate diameters without explicit segmentation. In a way, this is similar to the task of counting objects without directly counting them. Such calculations may, for example, be useful)Cast estimation of particle size in different application areas. The topic is that of estimating average size (=average diameter) of packed particles, from formulas involving edge density, and the edges from moment-based thresholding are used. An average shape factor is involved in the calculations, obtained for some frames from crude partial segmentation. Measurement results from about 80frames have been analyzed. 展开更多
关键词 edge density average size particle images automatic particle inspection edge detection moment-based thresholding
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The Study of Full-Size Objects’ Bistatic Rader Cross Section Measurement Based on Photoelectric Conversion
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作者 Yilong Chen Tao Hong Zhihua Chen 《Optics and Photonics Journal》 2016年第8期24-29,共6页
In the past years, bistatic Radar Cross Section (RCS) characteristic has been caught increasing attention. The paper presents a bistatic RCS measurement system of full-size goals, which uses photoelectric conversion t... In the past years, bistatic Radar Cross Section (RCS) characteristic has been caught increasing attention. The paper presents a bistatic RCS measurement system of full-size goals, which uses photoelectric conversion technology to solve the problem that excessive electrical signal attenuation exits because of the large distance between sending and receiving antenna. The paper analyzes the basic principle of photoelectric conversion and RCS measurement system, applies photoelectric conversion technology to RCS measurement system, and tests whether RCS measurement system works well while using photoelectric conversion technology. The test results show that the system can efficiently obtain the bistatic RCS characteristic of full-size targets. 展开更多
关键词 Full-size Targets Bistatic RCS Characteristic Photoelectric Conversion technology
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Construction and Properties of Structure-and Size-controlled Micro/Nano-energetic Materials 被引量:20
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作者 HUANG Bing CAO Minhua +2 位作者 NIE Fude HUANG Hui HU Changwen 《Defence Technology(防务技术)》 SCIE EI CAS 2013年第2期75-103,共29页
The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development... The recent research progress of structure- and size-controlled micro/nano-energetic materials is reviewed, which properties are fundamentally different from those of their corresponding bulk materials. The development of the construction strategies for achieving zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) micro/nanostructures from energetic molecules is introduced. Also, an overview of the unique properties induced by micro/nanostructures and size effects is provided. Special emphasis is focused on the size-dependent properties that are different from those of the conventional micro-sized energetic materials, such as thermal decomposition, sensitivity, combustion and detonation, and compaction behaviors. A conclusion and our view of the future development of micro/nano-energetic materials and devices are given. 展开更多
关键词 applied chemistry STRUCTURE size micro/nano-energetic materials construction technology PROPERTY
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Effect of nano-particle size on product distribution and kinetic parameters of Fe/Cu/La catalyst in Fischer-Tropsch synthesis 被引量:4
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作者 Ali Nakhaei Pour Mohammad Reza Housaindokht +1 位作者 Sayyed Faramarz Tayyari Jamshid Zarkesh 《Journal of Natural Gas Chemistry》 EI CAS CSCD 2010年第2期107-116,共10页
Effects of nano-particle size on hydrocarbon production rates and distributions for precipitated Fe/Cu/La catalysts in Fischer-Tropsch synthesis were investigated.Nano-structured iron catalyst was prepared by micro-em... Effects of nano-particle size on hydrocarbon production rates and distributions for precipitated Fe/Cu/La catalysts in Fischer-Tropsch synthesis were investigated.Nano-structured iron catalyst was prepared by micro-emulsion method.The concept of two superimposed AndersonSchulz-Flory (ASF) distributions has been applied for the representation of the effects of reaction conditions and nano-particles size on kinetics parameters and product distributions.These results reveal that by reducing the particle size of catalyst,the break in ASF distributions was decreased.Also useful different kinetics equations for synthesis of C3 to C9 and C10 to C22 were determined by using α1 and α2 chain growth probabilities. 展开更多
关键词 chain length distribution Fischer-Tropsch synthesis iron-based catalyst nano-particle size
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Influence of Specimen Size on Compression Behavior of Cement Paste and Mortar under High Strain Rates 被引量:2
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作者 陈徐东 chen chen +1 位作者 qian pingping xu lingyu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第2期300-306,共7页
Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes(Ф68 mm×32 mm,Ф59 mm×29.5 mm and Ф32 mm×16 mm)to study the influence of specimen size on the compre... Static and dynamic compression tests were carried out on mortar and paste specimens of three sizes(Ф68 mm×32 mm,Ф59 mm×29.5 mm and Ф32 mm×16 mm)to study the influence of specimen size on the compression behavior of cement-based materials under high strain rates.The static tests were applied using a universalservo-hydraulic system,and the dynamic tests were applied by a spilt Hopkinson pressure bar(SHPB)system.The experimentalresults show that for mortar and paste specimens,the dynamic compressive strength is greater than the quasi-static one,and the dynamic compressive strength for specimens of large size is lower than those of smallsize.However,the dynamic increase factors(DIF)has an opposite trend.Obviously,both strain rate and size effect exist in mortar and paste.The test results were then analyzed using Weibull,Carpinteriand Ba?ant's size effect laws.A good agreement between these three laws and the test results was reached on the compressive strength.However,for the experimentalresults of paste and cement mortar,the size effect is not evident for the peak strain and elastic modulus of paste and cement mortar. 展开更多
关键词 size effect cement-based materials dynamic loading compressive behavior
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Differences Among Industrial Companies in Their Innovative Efforts and Competitiveness: On How Size, Technological Level and Subcontractor Character Matter
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作者 Ricardo Martinez Santa Maria Jon Charterina Abando Andres Araujo de la Mata 《Chinese Business Review》 2011年第3期187-204,共18页
The aim of this research is to test to what extent do the classifying variables of company size, technological level and subcontractor nature moderate on the causal relationship between a finn's innovative capacities... The aim of this research is to test to what extent do the classifying variables of company size, technological level and subcontractor nature moderate on the causal relationship between a finn's innovative capacities and its competitiveness. To this end, we use a random sample of 861 manufactttring f'Lrms with 10 or more employees from the Basque Autonomous Community (in Spain), accounting for 26.29% of the population. Maximum sampling error is 2.87% for a 95% confidence interval. We start from a competitiveness general model of the firm, and set out under the resource based view of the finn, which had been previously tested and validated by Martinez (2009) for the whole sample. The model is formed with the constructs of management capabilities, innovative capabilities, marketing capabilities, quality capabilities, current competitiveness and future competitiveness. From this point, we test a set of alternative hierarchical models both for the total sample and for different divisions in sub-samples, according to the intervals of size in number of employees, OECD technological levels and firms' subcontractor character. The innovative capabilities construct is reflected in the items of radical product innovation, incremental product innovation, innovation in the production process, innovation in marketing, management innovation and the efforts in company workers' training and development. From all these items, previous descriptive data analysis showed that although product radical innovation was the most representative capability for superior innovativeness, it was at the same time the least evident from all the aforementioned items in the case of the analyzed Basque industrial companies. The analysis of results led us to conclude that the factor of innovative capabilities was the most influential on current competitiveness among the whole sample. In particular, as regards the size factor, this positive effect dilutes in the case of smaller companies. In the same manner, whereas in the case of the companies with higher technological level it is verified that the factor of innovative capabilities reveals crucial, in the group of fhans with lower technological level the most relevant factor is quality. Also, the same effect is evidenced for the case of the subcontractor/non-subcontractor nature of the finns: The first ones show quality as the most relevant construct while for the second ones it is the innovative capabilities. 展开更多
关键词 COMPETITIVENESS innovative capabilities company size technological level subcontractor character
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Relationship between Grain Size and Fatigue-Creep Interaction Behaviour of Superalloy GH698
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作者 杨王玥 张济山 +2 位作者 陈国良 田树森 耿清全 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1989年第1期19-25,共7页
The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain... The deformation and fracture behaviour of nickel-base superalloy GH698 with different grain size have been studied at 700℃ under fatigue-creep interaction conditions. Compared with coarse-grained specimens, the grain refining process shows obvious effect on the mechanical behaviour of the alloy, i. e. in F and C zones, the fraction of pure fatigue and creep fracture on fracture surfaces is greatly reduced, which decreases and increases the fracture life in zones F and C respectively, in FC and C zones, creep deformation is greatly restrained by the alternating stress component, which increases the fracture life remarkably. It is also proved that in spite of the difference in microstru- tures such as grain size, for a constant tem- perature, a unique life equation t_r=A^n can be used to predict rupture life within the stress region controlled by the same fracture mode. 展开更多
关键词 Ni-base superalloy rupture life equation grain size
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Sex Ratio and Sexual Size Dimorphism in a Toad-headed Lizard, Phrynocephalus guinanensis
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作者 Kailong ZHANG Haojie TONG +2 位作者 Yubin WO Naifa LIU Yuanting JIN 《Asian Herpetological Research》 SCIE CSCD 2018年第1期35-42,共8页
Phrynocephalus guinanensis has sexual dimorphism in abdominal coloration, but its ontogenetic development of sexual size dimorphism (SSD) is unknown. Using mark-recapture data during four days each year from August ... Phrynocephalus guinanensis has sexual dimorphism in abdominal coloration, but its ontogenetic development of sexual size dimorphism (SSD) is unknown. Using mark-recapture data during four days each year from August from 2014 to 2016, we investigated the development of sex ratios, SSD, sex-specific survivorship and growth rates in a population of P guinanensis. Our results indicated that the sex ratio of males to females was 1:2.8. Males had a lower survival rate (6%) than females (14%) across the age range from hatchling to adult, which supported the discovered female-biased sex ratio potentially associated with the low survival rate of males between hatchlings and juveniles. Male-biased SSD in tail length and head width existed in adults rather than in hatchling or juvenile lizards. The growth rates in body dimensions were undistinguishable between the sexes during the age from hatchling to juvenile, but the growth rate in head length from juvenile to adult was significantly larger in males than females. Average growth rate of all morphological measurements from hatchling to juvenile were larger compared with corresponding measurements from juvenile to adult, but only being significant in tail length, head width, abdomen length in females and snout-vent length in males. We provided a case study to strengthen our understanding of the important life history traits on how a viviparous lizard population can survive and develop their morphology in cold climates. 展开更多
关键词 toad-headed lizard mark-RECAPTURE sexual size dimorphism growth rate SURVIVORSHIP sex ratio
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Research on the Informatilization of the Small-medium Sized Technological Enterprise in China
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作者 Zhimin Huang Haiyan Guo 《Chinese Business Review》 2003年第3期17-25,共9页
The paper analyses the necessity and importance of enterprise informatilization in Small-medium Sized technological enterprises in China. Considering the problems existing in the informatilization, the authors suggest... The paper analyses the necessity and importance of enterprise informatilization in Small-medium Sized technological enterprises in China. Considering the problems existing in the informatilization, the authors suggest that some problems and countermeasures be paid special attention when the enterprises promote their survival and development by informatilization. 展开更多
关键词 the Small-medium sized technological enterprises informatilization China
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Simulation of Electrical Discharge Initiated by a Nanometer-Sized Probe in Atmospheric Conditions
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作者 陈然 陈池来 +5 位作者 刘友江 王焕钦 马源 Michael CADA Jrgen BRUGGER 孔德义 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第9期845-851,共7页
In this paper, a two-dimensional nanometer scale tip-plate discharge model has been employed to study nanoscale electrical discharge in atmospheric conditions. The field strength dis- tributions in a nanometer scale t... In this paper, a two-dimensional nanometer scale tip-plate discharge model has been employed to study nanoscale electrical discharge in atmospheric conditions. The field strength dis- tributions in a nanometer scale tip-to-plate electrode arrangement were calculated using the finite element analysis (FEA) method, and the influences of applied voltage amplitude and frequency as well as gas gap distance on the variation of effective discharge range (EDR) on the plate were also investigated and discussed. The simulation results show that the probe with a wide tip will cause a larger effective discharge range on the plate; the field strength in the gap is notably higher than that induced by the sharp tip probe; the effective discharge range will increase linearly with the rise of excitation voltage, and decrease nonlinearly with the rise of gap length. In addition, probe dimension, especially the width/height ratio, affects the effective discharge range in different manners. With the width/height ratio rising from 1 : 1 to 1 : 10, the effective discharge range will maintain stable when the excitation voltage is around 50 V. This will increase when the excitation voltage gets higher and decrease as the excitation voltage gets lower. Fhrthermore, when the gap length is 5 nm and the excitation voltage is below 20 V, the diameter of EDR in our simulation is about 150 nm, which is consistent with the experiment results reported by other research groups. Our work provides a preliminary understanding of nanometer scale discharges and establishes a predictive structure-behavior relationship. 展开更多
关键词 nanodischarge nanoscale AFM probe Peek's formula modified Paschencurve effective discharge range probe based data storage nanometer-sized ion source
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With Respect to Academic Achievement, How Important is Class Size? 被引量:1
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作者 刘晓静 《海外英语》 2012年第2X期276-276,共1页
This essay will discuss how important the influence of class size is on academic achievement.
关键词 ACADEMIC ACHIEVEMENT class size Applications of GR
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知识搜寻与重构如何促进专精特新中小企业绿色技术创新——战略柔性与激励型环境规制的调节作用 被引量:1
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作者 李金生 柯雯 《科技进步与对策》 北大核心 2024年第7期111-121,共11页
专精特新中小企业的创新实力和发展韧性较强,如何促进其绿色技术创新对于实现“双碳”目标和企业可持续发展具有重要意义。基于组织搜寻与知识管理理论,引入知识重构作为中介变量,战略柔性与激励型环境规制作为调节变量,探究知识搜寻对... 专精特新中小企业的创新实力和发展韧性较强,如何促进其绿色技术创新对于实现“双碳”目标和企业可持续发展具有重要意义。基于组织搜寻与知识管理理论,引入知识重构作为中介变量,战略柔性与激励型环境规制作为调节变量,探究知识搜寻对专精特新中小企业绿色技术创新的内在作用机制。基于272家专精特新中小企业调查数据,通过层次回归、Bootstrap等方法进行分析。结果表明:市场知识搜寻与技术知识搜寻均对专精特新中小企业绿色技术创新具有显著影响;知识重构在市场知识搜寻、技术知识搜寻与专精特新中小企业绿色技术创新之间起部分中介作用;战略柔性正向调节知识搜寻对知识重构的影响;激励型环境规制正向调节知识重构对专精特新中小企业绿色技术创新的影响。 展开更多
关键词 专精特新中小企业 知识搜寻 知识重构 绿色技术创新 战略柔性
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新型连续流系统中Anammox颗粒粒径控制策略研究
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作者 李冬 李崧岳 +4 位作者 董怡雯 蒋鹏飞 李帅 曾辉平 张杰 《中国环境科学》 EI CAS CSCD 北大核心 2024年第8期4355-4365,共11页
以具有自主专利的新型大/小双室自回流连续流反应器为平台,探究基于粒径回流的Anammox颗粒污泥粒径调控策略及调控机制.粒径回流策略通过改变内循环的位置,将不同粒径的污泥引入高基质浓度和高机械剪切区域进行粒径调控.结果表明,粒径... 以具有自主专利的新型大/小双室自回流连续流反应器为平台,探究基于粒径回流的Anammox颗粒污泥粒径调控策略及调控机制.粒径回流策略通过改变内循环的位置,将不同粒径的污泥引入高基质浓度和高机械剪切区域进行粒径调控.结果表明,粒径回流策略能够提高Anammox颗粒粒径,并将其控制在合适的范围内.这一策略还增强了系统的污泥浓度、颗粒沉降性能和脱氮性能.其中大颗粒回流策略综合提升效果最佳,维持颗粒粒径在0.5~1.6mm范围内,中值粒径为948μm,污泥体积指数(SVI)为35.6mL/g,总无机氮(TIN)去除率为88.59%.胞外聚合物(EPS)分析和分层实验表明,紧密结合EPS(TB-EPS)中的蛋白质(PN)在粒径调控中起着关键作用,高浓度的外层污泥PN主导了颗粒的沉降性能,而内层紧实污泥的TB-EPS中的PN则增强了颗粒的结构强度.高通量测序结果表明,粒径循环策略能够大幅提高系统内厌氧氨氧化菌(AnAOB)Candidatus Kuenenia的丰度,在大颗粒回流时达到60.24%的峰值,并且AnAOB主要分布在颗粒污泥内层. 展开更多
关键词 厌氧氨氧化 颗粒污泥 连续流 粒径控制 粒径回流
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小尺寸压蒸试件的MgO水泥基材料微观结构研究
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作者 李维维 宋子宇 +2 位作者 赵振华 卢炜 徐再贤 《水利水电科技进展》 CSCD 北大核心 2024年第5期60-64,79,共6页
为促进MgO混凝土的推广应用,采用汞孔隙率法和扫描电子显微镜法对小尺寸压蒸试件的MgO水泥基材料(水泥砂浆和一级配混凝土砂浆)的微观结构进行了研究。结果表明:随着试件尺寸的变化,MgO水泥基材料的平均孔径由大到小的排序为微试件、小... 为促进MgO混凝土的推广应用,采用汞孔隙率法和扫描电子显微镜法对小尺寸压蒸试件的MgO水泥基材料(水泥砂浆和一级配混凝土砂浆)的微观结构进行了研究。结果表明:随着试件尺寸的变化,MgO水泥基材料的平均孔径由大到小的排序为微试件、小试件、标准试件;无害孔和少害孔占比由大到小的排序为标准试件、小试件、微试件;MgO掺量相同时,随着粉煤灰掺量的增大,与小试件和微试件相比,标准试件的平均孔径最小,而无害孔和少害孔占比最大。 展开更多
关键词 MgO水泥基材料 微观结构 小尺寸压蒸试件 粉煤灰
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政府支出规模对创新的影响——促进抑或阻碍
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作者 冯海波 陈韵洁 +1 位作者 周明明 刘勇政 《南开经济研究》 北大核心 2024年第1期20-38,共19页
自中国经济步入“新常态”以来,创新已然成为中国未来经济可持续发展的重要动力。本文首先在理论层面上分析了政府支出对创新的正向激励效应和负向挤出效应,然后基于2007—2017年中国269个地级市的面板数据,实证检验了中国政府支出规模... 自中国经济步入“新常态”以来,创新已然成为中国未来经济可持续发展的重要动力。本文首先在理论层面上分析了政府支出对创新的正向激励效应和负向挤出效应,然后基于2007—2017年中国269个地级市的面板数据,实证检验了中国政府支出规模的创新效应,意在探索有利于促进创新的政府支出规模和结构。实证结果表明,从整体上看,中国当前的政府支出规模对创新具有显著的正向促进作用,并且这一作用主要是由政府支出中的科学技术支出和福利性支出对创新活动的正向激励效应所驱动。与此同时,政府支出规模对创新的影响呈现出明显的地区差异和创新质量差异:在人均科学技术支出和人均福利性支出更多的东部与中部地区,政府支出规模的正向激励效应表现得更为显著;科学技术支出会同时促进高质量和低质量的创新活动,而福利性支出只促进低质量的创新活动。 展开更多
关键词 政府支出规模 创新 正向激励效应 科学技术支出 福利性支出
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