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Soil c and N dynamics and maize (Zea may L.) yield as affected by croping systems and residue management in North-western Pakistan

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SOIL & TILLAGE RESEARcH 2007年第2期94卷 520-529页

作者： Shafi, Mohammad Bakht, Jehan Jan, Mohammad Tariq Shah, Zahir Agr Univ NWFP Dept Agron Peshawar Pakistan Agr Univ NWFP Dept Soil Sci & Environm Sci Peshawar Pakistan

This paper presents the results of irrigated rotation experiment, conducted in the North West Frontier Province (NWFP), Pakistan, during 1999-2002 to evaluate effects of residues retention, fertilizer N and legumes in crop rotation on yield of maize (Zea mays L.) and soil organic fertility. chickpea (cicer arietinum Q and wheat (Triticum aestivum Q were grown in the winters and mungbean (Vigna radiata) and maize in the summers. Immediately after grain harvest, above-ground residues of all crops were either completely removed (-residue), or spread across the plots and incorporated by chisel plough by disc harrow and rotavator (+residue). Fertlizer N rates were nil or 120 kg ha(-1) for wheat and nil or 160 kg ha(-1) for maize. Our results indicated that post-harvest incorporation of crop residues significantly (p < 0.05) increased the grain and stover yields of maize during both 2000 and 2001. On average, grain yield was increased by 23.7% and stover yield by 26.7% due to residue incorporation. Residue retention also enhanced N uptake by 28.3% in grain and 45.1% in stover of maize. The soil N fertility was improved by 29.2% due to residue retention. The maize grain and stover yields also responded significantly to the previous legume (chickpea) compared with the previous cereal (wheat) treatment. The legume treatment boosted grain yield of maize by 112% and stover yield by 133% with 64.4% increase in soil N fertility. Similarly, fertilizer N applied to previous wheat showed considerable carry over effect on grain (8.9%) and stover (40.7%) yields of the following maize. Application of fertilizer N to current maize substantially increased grain yield of maize by 110%, stover yield by 167% and soil N fertility by 9.8% over the nil N fertilizer treatment. We concluded from these experiments that returning of crop residues, application of fertilizer N and involvement of legumes in crop rotation greatly improves the N economy of the cropping systems and enhances crop produc

关键词： maize N c crop residues cropping systems

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RMI- c/c-Sic-ZrSi2 composite serving in inert atmosphere up to 2100 °c: Thermal shock resistance, microstructure and damage mechanism

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cERAMIcS INTERNATIONAL 2021年第14期47卷 20371-20378页

作者： Tong, Yonggang Zhang, Hao Hu, Yongle Zhang, Peng Hua, Manyu Liang, Xiubing chen, Yongxiong Zhang, Zhibing Changsha Univ Sci & Technol Coll Automobile & Mech Engn Changsha Peoples R China Acad Mil Sci PLA China Natl Inst Def Technol Innovat Beijing Peoples R China

Thermal shock resistance (TSR) and related damage mechanism of c/c-Sic-ZrSi2 composites produced via Si-Zr alloy melt infiltration was investigated using a newly-developed equipment at superior high temperatures up to 2100 degrees c in an inert atmosphere. TSR was characterized by the residual strength and mass variation of the composites subjecting to thermal shock tests with different cycles and temperatures. Results indicated that TSR and damage of the composites were closely dependent on the testing cycles and especially temperatures. Strength of the composites was generally decreased with the increasing tested cycles. Slight strength reduction subjected to the low testing temperatures (< 1300 degrees c) were detected because almost no crack propagation occurred in the c-Sic-ZrSi2 matrix. At relatively higher temperatures (1300-1700 degrees c), thermal stress caused by temperature gradient and thermal expansion coefficient mismatch was greatly increased. consequently, matrix crack propagating into the intra fiber bundles and interfacial layers with much longer propagation paths were generated. Repeated thermal stress during cycled thermal shock tests weakened the interface bonding in the composites, and resulted in the delamination and interfacial debonding with obvious strength degradation. At ultrahigh temperatures (>= 1700 degrees c), matrix pores were produced due to ZrSi2 evaporation. combining effect by thermal stress and ZrSi2 evaporation caused severe damage to the composites with sharp strength reduction.

关键词： Thermal shock resistance Microstructure Damage Reactive melt infiltration c c-Sic-ZrSi 2 composites

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HYDRATION MEcHANISM OF THE c3S WITH THE APPLIcATION OF THE SLOW EVAPORATION TEcHNIQUE IN ITS LIQUID-PHASE

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cEMENT AND cONcRETE RESEARcH 1986年第4期16卷 472-480页

作者： GOLDScHMIDT, A Laboratorio de Microanálisis Departamento de Geología Facultad de Ciencias Físicas y Matemáticas Universidad de Chile Casilla 13518 Correo 21 Santiago Chile

The morphology and chemical composition of the evaporation products of the liquid phase and the c 3 S paste were studied by Microprobe (EPMA) and Scanning Flectron Microscope (SEM). Results that support those of previous research were obtained, increasing these, since it was proved — by means of my research in a direct way, that morphologically and chemically speaking, products of c 3 S hydration and the ones obtained through slow evaporation of the liquid phase of the c 3 S water are different. chemically, in these products of evaporation, no correlation was found between the Si and ca, which appears to be an argument in favor of the topochemical hydration theory.

关键词： S SiO 2 c caO H H 2 O A A1 2 O 3

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Designed formation of c/Fe3O4@Ni(OH)2 cathode with enhanced pseudocapacitance for asymmetric supercapacitors

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JOURNAL OF cOLLOID AND INTERFAcE ScIENcE 2023年第1期635卷 176-185页

作者： Lv, Hui Xiao, Zuoyi Zhai, Shangru Wang, Xuting Hao, Jingai An, Qingda Dalian Polytech Univ Coll Light Ind & Chem Engn Liaoning Collaborat Innovat Ctr Lignocellulos Bior Liaoning Key Lab Lignocellulose Chem & Biomat Dalian 116034 Peoples R China

The rational design and synthesis of advanced electrode materials are significant for the applications of supercapacitors. Ferroferric oxide (Fe3O4), with its high theoretical capacitance is a renowned cathode material. Nevertheless, its low electronic conductivity and poor cycling stability during a long-term charge/discharge process limit its large-scale applications. In this work, the precise modulation of multiple components was reported to enhance electrochemical performance. The ternary heterostructures were fabricated by wrapping ultrathin nickel hydroxide (Ni(OH)2) nanosheets on the surfaces of Fe3O4 nanoparticles-loaded on sodium carboxymethyl cellulose (cMc)-derived porous carbon, named as c/ Fe3O4@Ni(OH)2. Due to the large specific surface area and excellent conductivity of cMc-derived porous carbon and the abundant reaction sites of Ni(OH)2 nanosheets, the optimized c/Fe3O4@Ni(OH)2-1.0 sample exhibited the highest specific capacitance of 3072F g-1 at a current density of 0.5 A g-1. Furthermore, the assembled asymmetric supercapacitor (ASc) with activated carbon and c/Fe3O4@Ni(OH)2-1.0 as the negative and positive electrodes, respectively, showed an energy density of 123 W h kg-1 at 381 W kg-1, and a long-life stability with an excellent capacitance retention of 90.04 % after 10,000 cycles. The route for preparing composite electrode materials proposed in this work provides a reference for realizing highperformance energy storage devices.(c) 2022 Elsevier Inc. All rights reserved.

关键词： cMc Supercapacitor c Ni(OH)2 nanosheet

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Acinetobacter sp. mediated synthesis of AgNPs, its optimization, characterization and synergistic antifungal activity against c. albicans

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JOURNAL OF APPLIED MIcROBIOLOGY 2019年第2期127卷 445-458页

作者： Nadhe, S. B. Singh, R. Wadhwani, S. A. chopade, B. A. Savitribai Phule Pune Univ Dept Microbiol Pune Maharashtra India SIES Coll Arts Sci & Commerce Dept Biotechnol Mumbai Maharashtra India Dr Babasaheb Ambedkar Marathwada Univ Aurangabad 431004 Maharashtra India

Aims To synthesize silver nanoparticles (AgNPs) with cell free extract of Acinetobacter sp. and evaluate antifungal activity against planktonic and biofilm of candida. Also, to study mechanism of antifungal action of AgNPs. Methods and Result Acinetobacter spp were screened for synthesis of AgNPs. Physio-chemical parameters were optimized to obtained monodispersed nanoparticles. Optimized nanoparticles were characterized using spectroscopic, microscopic and diffraction techniques. Antifungal and biofilm disruption activity of AgNPs (10 +/- 5 nm) were investigated against c. albicans. Mechanism of antifungal activity of nanosilver was deduced by growth curve, reactive oxygen species generation, thiol interaction and microscopic analysis. Acinetobacter sp. GWRFH 45 gave maximum synthesis of AgNPs. At optimized condition monodispersed, spherical nanoparticles were obtained which were crystalline with negative surface charge. AgNPs exhibited antifungal activity against planktonic cells and biofilm of candida. AgNPs showed synergistic effect with amphotericin B as well as fluconazole against biofilm disruption. AgNPs were found to affect growth of candida, generate reactive oxygen species and disrupt cellular morphology. conclusions cell free extract of A. calcoaceticus GWRFH 45 has ability to synthesize AgNPs. AgNPs alone and in combination with drugs have potential to inhibit c. albicans. Significance and Impact of the Study This is the first report of bacteriogenic AgNPs used in combination with antifungal drugs against candida.

关键词： Acinetobacter sp AgNPs antifungal biofilm c albicans disrupt morphology reactive oxygen species

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The effect of Ru/c and Mgcl2 on the cleavage of inter- and intra-molecular linkages during cornstalk hydrolysis residue valorization

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cELLULOSE 2020年第2期27卷 799-823页

作者： Lv, Wei Liao, Yuhe Zhu, Yuting Liu, Jing Zhu, changhui Wang, chenguang Xu, Ying Zhang, Qi chen, Guanyi Ma, Longlong Chinese Acad Sci Guangzhou Inst Energy Convers CAS Key Lab Renewable Energy Guangdong Prov Key Lab New & Renewable Energy Res 2 Nengyuan Rd Guangzhou 510640 Peoples R China Tianjin Univ Sch Environm Sci & Engn 92 Weijin Rd Tianjin 300000 Peoples R China Katholieke Univ Leuven Ctr Surface Chem & Catalysis Celestijnenlaan 200F B-3001 Heverlee Belgium Key Lab Biomass Energy & Mat 16 5th Suojin Village Nanjing 210018 Jiangsu Peoples R China

The cleavage of linkages of lignocellulose is important for its valorization. The linkage cleavage of cornstalk hydrolysis residue was investigated over catalysts (Ru/c + Mgcl2) in EtOAc/H2O solvents. The results show that almost hydrogen bonds, c-c bonds, ether and ester bonds in the matrix of lignin and cellulose were broken, accompanying 80.6% of lignin and 98.5% of cellulose conversion, and obtaining 37.5% of aromatic monomers and 28.8% of lignin oligomers. In the reaction system, biphasic EtOAc/H2O solvents exhibited an effect on cleaving the intermolecular linkages between lignin and cellulose. Mgcl2 showed limited abilities of breaking the alpha-O-4 and beta-O-4 linkages in lignin and limited beta-1, 4-glycosidic and hydrogen bonds in cellulose were cleaved over Ru/c catalyst. The cleavage of c-O linkages (alpha-O-4, beta-O-4, 4-O-5) and c-c bonds (alpha-beta, beta-5) in lignin were mainly dependent on Ru/c catalyst. Much c-O and the stubborn c-c linkages of beta-5, beta-1 and 5-5 were significantly disrupted by the synergistic effect between Mgcl2 and Ru/c. However, Mgcl2 exhibited great contribution to breakage of beta-1, 4-glycosidic linkage, hydrogen bonds and sugar ring of cellulose. The linkage of beta-1, 4-glycosidic, hydrogen bonds and c-c in c5/c6 sugars were significantly broken. The increased yield of products was evidently due to the synergistic effect of Ru/c combined with Mgcl2.

关键词： cleavage of linkage Biphasic EtOAc H2O solvents Ru c Mgcl2 cornstalk hydrolysis residue (cHR) Valorization

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Parameters Optimization of Laser-Grinding chain for Processing Groove of 2.5-Dimensional c/Sic composites

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MATERIALS 2023年第13期16卷 4761-4761页

作者： Liu, Guoyue Wang, Jian chen, Bing Guo, Bing Zhang, Hua Wang, Zhaohui Hunan Univ Sci & Technol Sch Mech Engn Hunan Prov Key Lab High Efficiency & Precis Machin Xiangtan 411201 Peoples R China Hunan Taijia New Mat Technol Co Ltd Changsha 410203 Peoples R China Harbin Inst Technol Ctr Precis Engn Sch Mechatron Engn Harbin 150001 Peoples R China Wuhan Univ Sci & Technol Coll Mech Automat Wuhan 430081 Peoples R China

Aiming at problems such as poor precision of laser processing c/Sic composites, low efficiency of grinding c/Sic composites, and serious wear of grinding wheel, a method of laser-grinding chain processing c/Sic composite groove was proposed in this paper. The method combined the high efficiency characteristic of laser ablating and the high precision characteristic of grinding. The relationship between laser processing parameters and the characteristics of ablative grooves was investigated, and the appropriate laser processing parameters were optimized, and then, to further improve the processing quality of the grooves, the grinding parameters optimization experiments of the grooves of c/Sic composites were carried out. The results showed that the c/Sic composites could be quickly removed by laser processing, and the grooves with relatively good size and shape accuracy could be obtained by laser parameters optimization experiments, but the side wall of the groove still had a certain inclination and the surface quality of the groove was yet poor;meanwhile, the size accuracy, shape accuracy, and surface quality of the grooves were greatly improved by further grinding. In addition, then, through the laser and grinding optimization experiments, the optimized parameters were obtained, where the laser power was 80 W, the scanning speed was 300 mm/s, the scanning frequency was 50 kHz, the scanning spacing was 25 & mu;m, the depth of cut was 30 & mu;m, the liner speed of wheel was 62.832 m/min, and the feed speed was 10 mm/min. With these parameters, the time used to process the groove with the laser-grinding chain was about 23/40 of the grinding process, and the quality of grooves could be guaranteed. Therefore, combined with the optimized process parameters, the laser-grinding chain processing scheme could be used to achieve high efficiency and precision grinding of c/Sic composite grooves.

关键词： c Sic composite laser-grinding chain processing groove feature parameter optimization

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Regenerated LiFePO4/c for scrapped lithium iron phosphate powder batteries by pre-oxidation and reduction method

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IONIcS 2022年第5期28卷 2125-2133页

作者： Zhang, Hao Wang, Lihua chen, Yongzhi Wen, Xu Changsha Univ Coll Mech & Elect Engn Changsha 410022 Peoples R China Hunan Inst Sci & Technol Coll Mech Engn Yueyang 414006 Peoples R China

The cathode materials of scrapped lithium-iron phosphate battery are mainly composed of LiFePO4/c, conductive agent and PVDF, etc. Unreasonable disposal will cause serious environmental pollution and waste of scarce resources. In this paper, cathode materials were regenerated by pre-oxidation and reduction method. Impurities such as carbon coating, conductive agent, and PVDF were removed and LiFePO4/c was converted to Fe2O3 and Li3Fe2(PO4)(3) by pre-oxidation. After the addition of sucrose, regeneratedLiFePO(4)/c was synthesized under reduction process. The effects of calcination temperature and sucrose addition on the microstructure and electrochemical properties of regenerated LiFePO4/c were studied. The regenerated LiFePO4/c had excellent cycling stability when the sucrose addition was 12% and calcined at 700 celcius. The initial discharge specific capacity of regenerated LiFePO4/c was 145.51 mAh g(-1) at 0.5 c. After 200 cycles, the discharge specific capacity was 145.25 mAh g(-1) (capacity retention rate: 99.82%). It provides a new inspiration for the high-value recycling and regeneration of the other scrapped lithium-ion batteries.

关键词： Scrapped lithium-ion batteries Regenerated LiFePO4 c Pre-oxidation and reduction

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Thermal performance and ablation characteristics of c/c-Sic for thermal protection of hypersonic vehicle

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JOURNAL OF THE EUROPEAN cERAMIc SOcIETY 2021年第11期41卷 5427-5436页

作者： Shi, Yi-ang Zha, Bai-lin Su, Qing-dong Wang, Jin-jin Li, Si-ye Rocket Force Univ Engn Xian 710025 Peoples R China Project Management Ctr Beijing 100085 Peoples R China

A small-scale plasma ablation facility was employed to test the c/c-Sic composite material for investigating the thermal performance and ablation characteristics under two heat flux conditions, 3593.54 kW.m- 2 and 5644.86 kW.m-2. The morphology of post-test specimens was analyzed with the ablation rates calculated. The average mass ablation rates of two group specimens were 0.01735 and 0.10620 g.s-1 respectively with average linear ablation rate of 0.00680 and 0.09407 mm.s-s1. Specimen surface could be divided into three regions with typical layered structure characteristics. For the stagnation point ablation test, the structural deformation in the ablation surface area featured in vertical layering and lateral regionality, forming an ablation pit near the stagnation point. In the center region, sublimation occured primarily, accompanied by a serious jet scouring of the molten liquid phase, as well as a small amount of oxidation reaction;Jet erosion with thermal sublimation was the main factor for the mass loss in the transitional region;Thermochemical reactions were mainly carried out in the marginal region. The SiO2 generated from the thermochemical reaction of the material filled the interspace well and prevented the thermochemical reaction from penetrating deeper through the crack. The protective layer in the molten state with high viscosity reduced the damage of the high-speed jet impact material.

关键词： c c-Sic composite material Ablation rates Ablation characteristics Thermal protection performance

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A sound polymorphic type system for a dialect of c

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ScIENcE OF cOMPUTER PROGRAMMING 1998年第1-3期32卷 49-72页

作者： Smith, G Volpano, D Florida Int Univ Sch Comp Sci Miami FL 33199 USA USN Postgrad Sch Dept Comp Sci Monterey CA 93943 USA

Advanced polymorphic type systems have come to play an important role in the world of functional programming. But, so far, these type systems have had little impact upon widely used imperative programming languages like c and c++. We show that ML-style polymorphism can be integrated smoothly into a dialect of c, which we call Polymorphic c. It has the same pointer operations as c, including the address-of operator &, the dereferencing operator *, and pointer arithmetic. We give a natural semantics for Polymorphic c, and prove a type soundness theorem that gives a rigorous and useful characterization of what can go wrong when a well-typed Polymorphic c program is executed. For example, a well-typed Polymorphic c program may fail to terminate, or it may abort due to a dangling pointer error. Proving such a type soundness theorem requires a notion of an attempted program execution;we show that a natural semantics gives rise quite naturally to a transition semantics, which we call a natural transition semantics, that models program execution in terms of transformations of partial derivation trees. This technique should be generally useful in proving type soundness theorems for languages defined using natural semantics. (c) 1998 Elsevier Science B.V. All rights reserved.

关键词： c type systems polymorphism variables pointers type soundness natural semantics transition semantics

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