Post-synthetic functionalization or modification has been regarded as a promising strategy to treat surfaces of adsorbents for their applications in targeted adsorption and separation processes.In this work,a novel mi...Post-synthetic functionalization or modification has been regarded as a promising strategy to treat surfaces of adsorbents for their applications in targeted adsorption and separation processes.In this work,a novel microporous adsorbent for carbon capturing was developed via functionalization of zeolitic imidazolate framework-91(ZIF-91)to generate a hard/hard(metal-oxygen)structure named as lithium-modified ZIF-91(ZIF-91-OLi compound).To this purpose,the ZIF-91 compound as an intermediate product was achieved by reduction of ZIF-90 in the presence of NaBH4 as a good reducing agent.Afterwards,acidic hydrogen atoms in the hydroxyl groups of ZIF-91 were exchanged with lithium cations via reaction of n-BuLi compound as an organo lithium agent through an appropriate procedure.In particular,the as-synthesized ZIF-91-OLi operated as an excellent electron-rich center for CO2 adsorption through trapping the positive carbon centers in the CO2 molecule.DFT calculations revealed that the presence of lithium over the surface of ZIF-91-OLi adsorbent plays an effective role in double enhancement of CO2 storage via creating a strong negative charge center at the oxygen atoms of the imidazolate linker as a result of the lithium/hydrogen exchange system.Finally,the selectivity of CO2/N2 was investigated at different temperatures,revealing the ZIF-91-OLi as a selective adsorbent for industrial application.展开更多
The final fractural forms and variation status of hard inclusion samples under biaxial compression have been primarily studied in this paper. The lateral fractural forms of samples are mainly compressive shear fractu...The final fractural forms and variation status of hard inclusion samples under biaxial compression have been primarily studied in this paper. The lateral fractural forms of samples are mainly compressive shear fracture, two kinds appear on surface: one is strike slip fault with reversed thrust, and another is thrust. Some hard inclusions rupture and some do not while hard contact serves between hard inclusions and sample; main fracture bypasses hard inclusion while soft contact serves. Finally, process of stress concentration, yield, softening until failure for hard inclusions have been analysed under a certain condition.展开更多
This paper discusses experimental results of turnin g experiments on GCr15 bearing steel hardened to 60～64 HRC. The objective was to d etermine the effect of the cutting parameters on cutting force, chip morphology a...This paper discusses experimental results of turnin g experiments on GCr15 bearing steel hardened to 60～64 HRC. The objective was to d etermine the effect of the cutting parameters on cutting force, chip morphology and resultant workpiece surface quality, more specifically surface texture, micr ostructure alterations, changes in microhardness and residual stresses distribut ion. The changing rules of the main cutting force was shown in this paper which feature a increasing tendency with the improvement of the workpiece hardness wit hin the cutting parameter scope. The rule of cutting force changing with the wor kpiece hardness is accord to the traditional metal cutting theory. Stress value decrease with increasing cutting speed and workpiece hardness. The comparison of the machined surface roughness and harden layer depth of machined surface for d ifferent hardness is shown in Fig.1. The machined surface roughness is the worst when the workpiece hardness is around 50HRC. When the workpiece hardness is ove r 50HRC, the surface roughness value shows a descending tendency with the additi on hardness. The machined superficial harden layer depth shows an increasing ten dency with the improvement of the workpiece hardness. When the workpiece hardnes s is 50HRC the machined superficial harden layer depth is tiptop. When the workp iece hardness is over 50HRC the depth changes little with the addition of workpi ece hardness. The remnant stress status of the machined surface is shown in Fig. 2, which is press stress status both in surface and in base for less cutting par ameters under two kinds of cutting condition. But experiment results show that t ensile stress can be produced under uncomfortable cutting conditions. The deform ation created by the chip formation is reduced whereduce with [TPP126A,+35mm77mm,Z,PY#]Depth from surface (μm) ■ v=200m/min,f=0.24mm/r,ap=0.8mm,60HRC ● v=200m/min,f=0.15mm/r,ap=0.5mm,60HRC Fig.1 The subsurface residual stress between the two experimentsHardness (HRC) Fig.2 The surface finish vs. workpiece hardness the workpiece hardness is improved.展开更多
The paper contains description of a new quantitative method of evaluation of material hardness. First the essence of cognition subject, concerned with the hardness notion, has been discussed. Next some characteristics...The paper contains description of a new quantitative method of evaluation of material hardness. First the essence of cognition subject, concerned with the hardness notion, has been discussed. Next some characteristics of exemplary existing evaluation methods have been presented. Then the attention was paid to the mistakes present in understanding//reasoning of the discussed problem. The revolutionary new method is given in the next part of the paper by presenting functional and parametric characteristics of the process of local deformation of a material. At the end, the justification – with the essential meaning for investigations of present and newer materials – to introduce one unified quantitative method of hardness evaluation, has been delivered.展开更多
TiN/CrN multilayered hard coatings with TiCrN interlayer were deposited onhigh speed steel substrates by using a filtered cathodic vacuum arc technique. The structure andcomposition of the coatings were characterized ...TiN/CrN multilayered hard coatings with TiCrN interlayer were deposited onhigh speed steel substrates by using a filtered cathodic vacuum arc technique. The structure andcomposition of the coatings were characterized by scanning electron microscopy (SEM) and Augerelectron spectroscopy (AES). A high adhesion of up to 80 N was demonstrated by scratching tests forthe multi-layered coatings. Nanoindentation tests were performed to determine the hardness andelastic modulus of the coatings as a function of the multiplayer modulation period. It was observedthat the hardness of the multilayered coatings is higher than those of either TiN or CrN singlecoatings, and it increases with decreasing modulation periods, which is consistent with predictionsfrom the Hall-Petch type strengthening mechanism, though at small modulation periods, deviation fromthe Hall-Petch relation has been observed for the multilayered coatings. The life-span of drillscoated with TiN/CrN multilayered is triple as long as that coated with TiN layer.展开更多
Objective To determine the effects of water hardness on the toxicities of cobalt （Co） and nickel （Ni） to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to ...Objective To determine the effects of water hardness on the toxicities of cobalt （Co） and nickel （Ni） to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to cobalt （as COCI2） and nickel （as NiCI2） for 96 h in waters with two levels of hardness （＂hard＂ and ＂very hard＂, nominally 130 mg/L and 350 mg/L as CaCO3, respectively）. Results Water hardness had a significant effect on the acute toxicity of both elements. The 96 h LC50 values for Co were 91.7 mg/L and 204.8 mg/L in hard and very hard waters, respectively, and for Ni the 96 h LC50 values were 78.0 mg/L and 127.2 mg/L, respectively. Conclusion The fish were more sensitive to Co and Ni toxicity in hard water than in very hard water; very hard water protects C. fusca against the toxicity of Co and Ni.展开更多
在长江河口两翼广泛分布第一硬土层(FHSL),研究其形成机制及工程地质特性对工程建设具有很好的指导意义。根据调查资料(钻孔935个,累计进尺42128 m)和试验资料,首次精确确认了长江河口北翼第一硬土层分布界线,研究了第一硬土层的形成年...在长江河口两翼广泛分布第一硬土层(FHSL),研究其形成机制及工程地质特性对工程建设具有很好的指导意义。根据调查资料(钻孔935个,累计进尺42128 m)和试验资料,首次精确确认了长江河口北翼第一硬土层分布界线,研究了第一硬土层的形成年代、粒度特征、地球化学特征、工程地质特性等。研究表明:第一硬土层形成年龄为20~11 ka B.P.(多个光释光和14C测年资料);硬土层含水率随深度的增加有增大的趋势,表明气候自下向上逐渐变凉和变干;第一硬土层的颗粒级配、粒度分布频率曲线、C-M沉积图等特征显示,第一硬土层主要由粉砂、极细砂和粘土粒级组成,样品的粒度频率曲线主要呈单峰分布,反映出物质沉积前所受搬运营力性质单一,土体颗粒沉积以均匀悬浮占绝对优势,沉积环境是一种相对稳定的低能环境。第一硬土层的发育受气候控制,大致可以分为3个阶段:第1阶段(20~15 ka B.P.)为沉积与成土交替作用时期,且以沉积作用为主,硬土层剖面厚度主要受该阶段控制,至末次盛冰期结束;第2阶段(15~11 ka B.P.)为暴露成土期,这时洪水不能形成越岸沉积,加积作用基本停止,硬土层厚度不再明显增加,已形成的第一硬土区域受到频繁变迁的分合河网的侵蚀切割,形成多条不规则古河道和台地,硬土层逐渐脱水成陆,经历了风化成壤的过程;第3阶段(11 ka B.P.至今)为淹埋期,随着全新世的到来,气候变暖,海平面不断上升,硬土层被其上覆的海相沉积层掩埋,成岩作用开始直到现今。土体易溶盐含量较高,为典型氯盐渍土类型,自下而上具有从低变高的趋势,为海相层覆盖硬土层以后成岩过程造成的。展开更多
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文摘Post-synthetic functionalization or modification has been regarded as a promising strategy to treat surfaces of adsorbents for their applications in targeted adsorption and separation processes.In this work,a novel microporous adsorbent for carbon capturing was developed via functionalization of zeolitic imidazolate framework-91(ZIF-91)to generate a hard/hard(metal-oxygen)structure named as lithium-modified ZIF-91(ZIF-91-OLi compound).To this purpose,the ZIF-91 compound as an intermediate product was achieved by reduction of ZIF-90 in the presence of NaBH4 as a good reducing agent.Afterwards,acidic hydrogen atoms in the hydroxyl groups of ZIF-91 were exchanged with lithium cations via reaction of n-BuLi compound as an organo lithium agent through an appropriate procedure.In particular,the as-synthesized ZIF-91-OLi operated as an excellent electron-rich center for CO2 adsorption through trapping the positive carbon centers in the CO2 molecule.DFT calculations revealed that the presence of lithium over the surface of ZIF-91-OLi adsorbent plays an effective role in double enhancement of CO2 storage via creating a strong negative charge center at the oxygen atoms of the imidazolate linker as a result of the lithium/hydrogen exchange system.Finally,the selectivity of CO2/N2 was investigated at different temperatures,revealing the ZIF-91-OLi as a selective adsorbent for industrial application.
文摘The final fractural forms and variation status of hard inclusion samples under biaxial compression have been primarily studied in this paper. The lateral fractural forms of samples are mainly compressive shear fracture, two kinds appear on surface: one is strike slip fault with reversed thrust, and another is thrust. Some hard inclusions rupture and some do not while hard contact serves between hard inclusions and sample; main fracture bypasses hard inclusion while soft contact serves. Finally, process of stress concentration, yield, softening until failure for hard inclusions have been analysed under a certain condition.
文摘This paper discusses experimental results of turnin g experiments on GCr15 bearing steel hardened to 60～64 HRC. The objective was to d etermine the effect of the cutting parameters on cutting force, chip morphology and resultant workpiece surface quality, more specifically surface texture, micr ostructure alterations, changes in microhardness and residual stresses distribut ion. The changing rules of the main cutting force was shown in this paper which feature a increasing tendency with the improvement of the workpiece hardness wit hin the cutting parameter scope. The rule of cutting force changing with the wor kpiece hardness is accord to the traditional metal cutting theory. Stress value decrease with increasing cutting speed and workpiece hardness. The comparison of the machined surface roughness and harden layer depth of machined surface for d ifferent hardness is shown in Fig.1. The machined surface roughness is the worst when the workpiece hardness is around 50HRC. When the workpiece hardness is ove r 50HRC, the surface roughness value shows a descending tendency with the additi on hardness. The machined superficial harden layer depth shows an increasing ten dency with the improvement of the workpiece hardness. When the workpiece hardnes s is 50HRC the machined superficial harden layer depth is tiptop. When the workp iece hardness is over 50HRC the depth changes little with the addition of workpi ece hardness. The remnant stress status of the machined surface is shown in Fig. 2, which is press stress status both in surface and in base for less cutting par ameters under two kinds of cutting condition. But experiment results show that t ensile stress can be produced under uncomfortable cutting conditions. The deform ation created by the chip formation is reduced whereduce with [TPP126A,+35mm77mm,Z,PY#]Depth from surface (μm) ■ v=200m/min,f=0.24mm/r,ap=0.8mm,60HRC ● v=200m/min,f=0.15mm/r,ap=0.5mm,60HRC Fig.1 The subsurface residual stress between the two experimentsHardness (HRC) Fig.2 The surface finish vs. workpiece hardness the workpiece hardness is improved.
文摘The paper contains description of a new quantitative method of evaluation of material hardness. First the essence of cognition subject, concerned with the hardness notion, has been discussed. Next some characteristics of exemplary existing evaluation methods have been presented. Then the attention was paid to the mistakes present in understanding//reasoning of the discussed problem. The revolutionary new method is given in the next part of the paper by presenting functional and parametric characteristics of the process of local deformation of a material. At the end, the justification – with the essential meaning for investigations of present and newer materials – to introduce one unified quantitative method of hardness evaluation, has been delivered.
基金This work was financially supported by the Science Foundation of Lanzhou Institute Chemistry and Physics, Chinese Academy of Science (No.01-03).
文摘TiN/CrN multilayered hard coatings with TiCrN interlayer were deposited onhigh speed steel substrates by using a filtered cathodic vacuum arc technique. The structure andcomposition of the coatings were characterized by scanning electron microscopy (SEM) and Augerelectron spectroscopy (AES). A high adhesion of up to 80 N was demonstrated by scratching tests forthe multi-layered coatings. Nanoindentation tests were performed to determine the hardness andelastic modulus of the coatings as a function of the multiplayer modulation period. It was observedthat the hardness of the multilayered coatings is higher than those of either TiN or CrN singlecoatings, and it increases with decreasing modulation periods, which is consistent with predictionsfrom the Hall-Petch type strengthening mechanism, though at small modulation periods, deviation fromthe Hall-Petch relation has been observed for the multilayered coatings. The life-span of drillscoated with TiN/CrN multilayered is triple as long as that coated with TiN layer.
文摘Objective To determine the effects of water hardness on the toxicities of cobalt （Co） and nickel （Ni） to a freshwater fish, Capoetafusca. Methods Toxicity was investigated by static bioassay. Fish were exposed to cobalt （as COCI2） and nickel （as NiCI2） for 96 h in waters with two levels of hardness （＂hard＂ and ＂very hard＂, nominally 130 mg/L and 350 mg/L as CaCO3, respectively）. Results Water hardness had a significant effect on the acute toxicity of both elements. The 96 h LC50 values for Co were 91.7 mg/L and 204.8 mg/L in hard and very hard waters, respectively, and for Ni the 96 h LC50 values were 78.0 mg/L and 127.2 mg/L, respectively. Conclusion The fish were more sensitive to Co and Ni toxicity in hard water than in very hard water; very hard water protects C. fusca against the toxicity of Co and Ni.
文摘在长江河口两翼广泛分布第一硬土层(FHSL),研究其形成机制及工程地质特性对工程建设具有很好的指导意义。根据调查资料(钻孔935个,累计进尺42128 m)和试验资料,首次精确确认了长江河口北翼第一硬土层分布界线,研究了第一硬土层的形成年代、粒度特征、地球化学特征、工程地质特性等。研究表明:第一硬土层形成年龄为20~11 ka B.P.(多个光释光和14C测年资料);硬土层含水率随深度的增加有增大的趋势,表明气候自下向上逐渐变凉和变干;第一硬土层的颗粒级配、粒度分布频率曲线、C-M沉积图等特征显示,第一硬土层主要由粉砂、极细砂和粘土粒级组成,样品的粒度频率曲线主要呈单峰分布,反映出物质沉积前所受搬运营力性质单一,土体颗粒沉积以均匀悬浮占绝对优势,沉积环境是一种相对稳定的低能环境。第一硬土层的发育受气候控制,大致可以分为3个阶段:第1阶段(20~15 ka B.P.)为沉积与成土交替作用时期,且以沉积作用为主,硬土层剖面厚度主要受该阶段控制,至末次盛冰期结束;第2阶段(15~11 ka B.P.)为暴露成土期,这时洪水不能形成越岸沉积,加积作用基本停止,硬土层厚度不再明显增加,已形成的第一硬土区域受到频繁变迁的分合河网的侵蚀切割,形成多条不规则古河道和台地,硬土层逐渐脱水成陆,经历了风化成壤的过程;第3阶段(11 ka B.P.至今)为淹埋期,随着全新世的到来,气候变暖,海平面不断上升,硬土层被其上覆的海相沉积层掩埋,成岩作用开始直到现今。土体易溶盐含量较高,为典型氯盐渍土类型,自下而上具有从低变高的趋势,为海相层覆盖硬土层以后成岩过程造成的。
