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Elucidating the Role of Rh/c on the Pathways and Kinetics of Ketone-to-Secondary Amines Reaction

cHEMcATcHEM 2022年第1期14卷 e202101270-e202101270页

作者： Arteaga-Perez, Luis E. Manrique, Raydel Ortega, Maray castillo-Puchi, Francisca Fraile, Juan E. Jimenez, Romel Univ Bio Bio Wood Engn Dept Lab Thermal & Catalyt Proc LPTC UBB Av Collao 1202 Concepcion 4030000 Chile Univ Concepcion Dept Chem Engn Carbon & Catalysis Lab CarboCat Av Victor Lamas S-NEdificio Gustavo Pizarro Concepcion 4030000 Chile

Biomass-based amines have received a lot of attention due to their sustainability and carbon economy. Herein, the roles of the metal sites (Rh-0 or Pd-0) and operating conditions on the kinetics and reaction pathways of the heterogeneous catalytic amination of cyclohexanone with aniline have been discussed. Rh/c provides secondary amines with remarkable selectivity toward the hydrogenation product (sigma S-i=72 %). The hydrogenation rate over Rh-0 is 1.5-fold higher than that observed over Pd-0, while its dehydrogenation capacity diminished (r(D_Rh )=0.74 h(-1) and r(D_Pd)=1.32 h(-1)). This difference in the hydrogenation/dehydrogenation performance allows control over the selectivity via disproportionation of an imine intermediate. The kinetic observations can be represented using the Langmuir-Hinshelwood model, indicating that the formation of the aminal intermediate is the rate-limiting step. The apparent activation energy for this step on Rh/c (55 kJ/mol) was higher than that previously reported for Pd/c (48 kJ/mol).

关键词： amination ketone Rh c kinetics reaction pathway

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Sensitivity study of c/O logging measurements by Monte carlo method

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APPLIED RADIATION AND ISOTOPES 2022年第0期188卷 110400页

作者： Szucs, Jozsef Gabor Balazs, Laszlo Eotvos Lorand Univ Inst Geog & Earth Sci Dept Geophys & Space Sci Pazmany Peter Setany 1-C H-1117 Budapest Hungary

carbon oxygen ratio (c/O) logging has great importance in the accurate determination of hydrocarbon satura-tion in the reservoir region. This measurement is independent of the salinity of the formation water, unlike alternative logging methods. Analysis of the measurement requires modelling of the time-dependent coupled neutron-gamma field produced by the tool, which is most efficiently done by the Monte carlo (Mc) method. Mc simulation can be used to generate the gamma spectrum at the detectors of the probe for a variety of rock physics conditions and borehole environments and thus the c/O can be determined by the processing of the simulated gamma spectrum. The simulation results are used to derive the interpretation diagrams for the basic petro-physical effects and to investigate the role of the side effects. considering the industrial practice of log evalu-ation, the resolution and limitations of the method is quantified in the measurement space by defining a goodness factor based on the area of the interpretation chart. The focus of this paper is on detector arrangement, but it also covers the effect of porosity, lithology, and the casing.

关键词： c O logging Monte carlo McNP Well log interpretation Oil saturation Oil holdup

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characterisation of chemical damage on tissue structures by multispectral imaging and machine learning procedures: Alkaline hypochlorite effect in c. elegans

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cOMPUTERS IN BIOLOGY AND MEDIcINE 2022年 145卷 105477-105477页

作者： Verdu, Samuel Fuentes, cristina Barat, Jose M. Grau, Raul Univ Politecn Valencia Dept Tecnol Alimentos Valencia Spain

Multispectral imaging represents a powerful technique to maximise data collection and analysis for biological materials. It improves the exploitation and understanding of in vivo/vitro experiments. This work focused on testing the capability of multispectral imaging to characterise the tissue damage produced by alkaline hypochlorite on the body and eggs of the biological model c. elegans. To that end, three synchronisation processes with different final bleach and sodium hydroxide concentrations were performed. The impact of treatments was characterised by measuring egg viability and morphology, besides capturing multispectral images of both nematode bodies and eggs. Multispectral images consisted of seven slices captured from different wavelengths within the visible/infrared spectrum by different light-pass filters. The results showed dependence between increased alkaline hypochlorite concentration and loss of egg viability/morphology. This relation was also observed for the imaging data, which showed alterations to tissue transmittance for all the tested wavelengths for both bodies and eggs. Localised alterations related to alkaline hypochlorite diffusion through anatomical nematode orifices were recognised. Applying multivariate methods to imaging data successfully characterised tissue alterations, from which treatment type was predicted for both nematodes and eggs. Moreover, the alterations recorded by imaging data were also used to predict egg viability regardless of treatment type (0.94). The high correlation between the imaging data from nematodes and eggs with egg viability evidenced multispectral imaging's ability to characterise tissue damage and its possible practical application to study alterations to the tissues of this biological model.

关键词： Multispectral imaging Tissue damage Machine learning c elegans Egg viability Multivariate analytics

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comparative study of microstructure and ablation behaviour of c/c-Hfc-Sic composites prepared under two different conditions

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MATERIALS cHARAcTERIZATION 2022年 194卷

作者： Liu, Zhiqiang Fu, Qiangang Shi, Huilun Zhang, Jiaping Jia, Yujun Northwestern Polytech Univ State Key Lab Solidificat Proc Shaanxi Key Lab Fiber Reinforced Light Weight Com Xian 710072 Shaanxi Peoples R China

c/c-Sic-Hfc composites were prepared using reactive melt infiltration (RMI) under a vacuum (noted as HS-V) and normal pressure (noted as HS-NP), separately. The distribution of the introduced Sic and Hfc ceramics can be regulated by adjusting the RMI pressure. Different pressures of the environment at the high temperature stage led to the difference in volatilization of Si in the melt and the ratios of c and HfSi2 in unit volume on the surface of the sample, resulting in the different composition of the sample surface. A HfSi2-Hfc-Sic mixed layer was formed on the surface of HS-NP, while Hfc coating was formed on the surface of HS-V. HS-NP possessed better ablation performance than HS-V. After ablation for 120 s, its mass ablation rate decreased by 87.81%. The presence of HfSi2 improved the densification of HfO2 film, which made the ablation resistance of HS-NP better than HS-V. This work provides a guide for choosing an idea pressure condition during RMI to obtain c/c-Sic-Hfc composites with high ablation resistance.

关键词： c c composites Reactive melt infiltration Pressure Ablation

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commensurate Assembly of c60 on Black Phosphorus for Mixed-Dimensional van der Waals Transistors

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SMALL 2022年第10期18卷 2105916-2105916页

作者： Yun, Tae Keun Lee, Yangjin Kim, Min Je Park, Jeongwoo Kang, Donghee Kim, Seongchan choi, Young Jin Yi, Yeonjin Shong, Bonggeun cho, Jeong Ho Kim, Kwanpyo Yonsei Univ Dept Phys Seoul 03722 South Korea Inst for Basic Sci Korea Ctr Nanomed Seoul 03722 South Korea Yonsei Univ Dept Chem & Biomol Engn Seoul 03722 South Korea Hongik Univ Dept Chem Engn Seoul 04066 South Korea

2D crystals can serve as templates for the realization of new van der Waals (vdW) heterostructures via controlled assembly of low-dimensional functional components. Among available 2D crystals, black phosphorus (BP) is unique due to its puckered atomic surface topography, which may lead to strong epitaxial phenomena through guided vdW assembly. Here, it is demonstrated that a BP template can induce highly oriented assembly of c-60 molecular crystals. Transmission electron microscopy and theoretical analysis of the c-60/BP vdW heterostructure clearly confirm that the BP template results in oriented c-60 assembly with higher-order commensurism. Lateral and vertical devices with c-60/BP junctions are fabricated via a lithography-free clean process, which allows one to investigate the ideal electrical properties of pristine c-60/BP junctions. Effective tuning of the c-60/BP junction barrier from 0.2 to 0.5 eV and maximum on-current density higher than 10(4) mA cm(-2) are achieved with graphite/c-60/BP vertical vdW transistors. Due to the formation of high-quality c-60 film and the semitransparent graphite top-electrode, the vertical transistors show high photoresponsivities up to approximate to 100 A W-1 as well as a fast response time under visible light illumination.

关键词： black phosphorus c (60) fullerenes mixed-dimensional molecule epitaxy van der Waals heterostructures vertical transistors

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Siloxene-Functionalized Laser-Induced Graphene via c-O-Si Bonding for High-Performance Heavy Metal Sensing Patch Applications

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SMALL 2022年第25期18卷 2201247-2201247页

作者： Hui, Xue Sharma, Sudeep Sharifuzzaman, Md Abu Zahed, Md Shin, Young Do Seonu, Soo Kyeong Song, Hye Su Park, Jae Yeong Kwangwoon Univ Dept Elect Engn Seoul 139701 South Korea

Here, 2D Siloxene nanosheets are newly applied to functionalize porous laser-induced graphene (LIG) on polydimethylsiloxane, modify the surface chemical properties of LIG, and improve the heterogeneous electron transfer rate. Meanwhile, the newly generated c-O-Si crosslink boosts the binding of LIG and Siloxene. Thus, the Siloxene/LIG composite is used as the basic electrode material for the multifunctional detection of copper (cu) ions, pH, and temperature in human perspiration. Moreover, to enhance the sensing performance of cu ions, Siloxene/LIG is further modified by carbon nanotubes (cNTs). The fabricated Siloxene-cNT/LIG-based cu-ion sensor shows linear response within a wide range of 10-500 ppb and a low detection limit of 1.55 ppb. In addition, a pH sensor is integrated to calibrate for determining the accurate concentration of cu ions due to pH dependency of the cu-ion sensor. The polyaniline-deposited pH sensor demonstrates a good sensitivity of -64.81 mV pH(-1) over the pH range of 3-10. Furthermore, a temperature sensor for accurate skin temperature monitoring is also integrated and exhibits a stable linear resistance response with an excellent sensitivity of 9.147 ohm degrees c-1 (correlation coefficient of 0.139% degrees c-1). The flexible hybrid sensor is promising in applications of noninvasive heavy-metal ion detection and prediction of related diseases.

关键词： c -O -Si bonds flexible hybrid perspiration sensors noninvasive cu ions detection pH calibration Siloxene-functionalized laser-induced graphene

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Entanglement of Spatial and Energy Segmentation for c1 Pathways in cO2 Reduction on carbon Skeleton Supported Atomic catalysts

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ADVANcED ENERGY MATERIALS 2022年第14期12卷 2270057-2270057页

作者： Sun, Mingzi Wong, Hon Ho Wu, Tong Dougherty, Alan William Huang, Bolong Hong Kong Polytech Univ Dept Appl Biol & Chem Technol Hung Hom Kowloon Hong Kong 999077 Peoples R China Univ Hong Kong Dept Comp Sci Pokfulam Rd Hong Kong 999077 Peoples R China

Electroreduction of cO2 has become the most attractive approach to generate value-added chemicals and fuels. Products of single atomic catalysts (SAc) in cO2 reduction reaction reactions (cO2RR) are mostly limited to cO since the contributions of spatial and thermodynamic factors are not distinguished. To break through the challenges, comprehensive explorations in graphdiyne(GDY)-based SAc are made, to reveal detailed influences of active sites, elements, and adsorptions on the selectivity and reaction energy of the c-1 pathway. Unique d electrons dominated adsorption behaviors are identified, where the d(6) boundary is able to help screen out promising candidates for achieving complicated c2+ products. Based on spatial and thermodynamic factors, metal sites are still the most promising active sites. The transition metal based GDY-SAcs show element-dependent electroactivity towards different products in cO2RR. Meanwhile, the GDY-Pr and GDY-Pm SAcs are promising candidates for the cO2RR and even c-2 products in the future. This work supplies in-depth insights into the cO2RR to facilitate the design of efficient atomic catalysts in future work.

关键词： atomic catalysts c (1) pathway cO (2) reduction density functional theory graphdiyne

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Multi-scale quantitative study on dielectric properties of c-S-H synthesized by different molar ratio of ca/Si

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cONSTRUcTION AND BUILDING MATERIALS 2022年 360卷

作者： Liu, Jianglin Li, Yue Jin, caiyun Lin, Hui Li, Hongwen Li, Yinuo Liu, Yunze Beijing Univ Technol Beijing Key Lab Earthquake Engn & Struct Retrofit Key Lab Urban Secur & Disaster Engn Minist Educ Beijing 100124 Peoples R China Beijing Univ Technol Coll Appl Sci 100 Pingleyuan Beijing 100124 Peoples R China McGill Univ Mat Engn CO OP Montreal PQ Canada Beijing Univ Technol Coll Architecture & Civil Engn 100 Pingleyuan Beijing 100124 Peoples R China

The main hydration product of cement is c-S-H. c-S-H has a great influence on the electromagnetic properties, but there are few studies on the independent study of the electromagnetic properties of c-S-H. Therefore, nanocrystalline c-S-H was synthesized by caO and nano-SiO2, multi-scale analysis method was adopted, and the electromagnetic properties of its hydration products were analyzed from the mechanism. c-S-H powders with ca to Si molar ratio (c/S) of 0.8, 1.2, 1.6, 2.0 and 2.5 were synthesized and tested by the coaxial method. Four types of materials were defined in this paper: HPB (composed of nanocrystalline c-S-H, ca(OH)2, cacO3 and pore phase);cSH (composed of nanocrystalline c-S-H and pore phase with diameter less than 5 nm);P-cSH (composed of pore phase and cSH phase);c-cSH (composed of ca(OH)2, cacO3 and cSH phase). The complex permittivity and complex permeability of HPB with different c/S at 2-18 GHz were tested. The influence of molecular structure, interlayer physically bound water, phase types and content of HPB on the electromagnetic properties were investigated by XRD, MIP, N2 adsorption, TGA and 29Si NMR spectroscopy. The results showed that with the increase of c/S, the permittivity of cSH, P-cSH, c-cSH and HPB were decreased. Both ca(OH)2 phase and pore phase can reduce the permittivity and loss tangent of HPB. It was worth noting that the reduction degree of pores phase on the permittivity of the HPB were about 4 times than that of ca(OH)2 phase (or cacO3 phase). Meanwhile, the results confirmed that the carbonization of ca(OH)2 phases had no effect on the elec-tromagnetic properties of HPB.

关键词： c-S-H c S Dielectric properties Quantitative study Multi -scale analysis

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A combined Elevation Angle and c/N0 Weighting Method for GNSS PPP on Xiaomi MI8 Smartphones

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SENSORS 2022年第7期22卷 2804页

作者： Li, Yanjie cai, changsheng Xu, Zhenyu Cent South Univ Sch Geosci & Infophys Changsha 410083 Peoples R China

Traditionally, an elevation-angle-dependent weighting method is usually used for Global Navigation Satellite System (GNSS) positioning with a geodetic receiver. As smartphones adopt linearly polarized antenna and low-cost GNSS chips, different GNSS observation properties are exhibited. As a result, a carrier-to-noise ratio (c/N0)-dependent weighting method is mostly used for smartphone-based GNSS positioning. However, the c/N0 is subject to the effects of the observation environment, resulting in an unstable observation weight. In this study, we propose a combined elevation angle and c/N0 weighting method for smartphone-based GNSS precise point positioning (PPP) by normalizing the c/N0-derived variances to the scale of the elevation-angle-derived variances. The proposed weighting method is validated in two kinematic PPP tests with different satellite visibility conditions. compared with the elevation-angle-only and c/N0-only weighting methods, the combined weighting method can effectively enhance the smartphone-based PPP accuracy in a three-dimensional position by 22.7% and 24.2% in an open-sky area, and by 52.0% and 26.0% in a constrained visibility area, respectively.

关键词： GNSS smartphone precise point positioning elevation angle c N0

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coupling between thermal ageing/degradation and creep behavior of PEKK and c/PEKK composites above the glass transition temperature

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cOMPOSITES PART A-APPLIED ScIENcE AND MANUFAcTURING 2022年第0期153卷 106717-106717页

作者： Pedoto, Giuseppe Grandidier, Jean-claude Gigliotti, Marco Vinet, Alain Univ Poitiers Inst Pprime CNRS Dept Phys & Mecan Mat ISAE ENSMA Poitiers France Airbus SAS Bldg D4218 Marius Terce F-31025 Toulouse France

The present work aims at investigating the coupling between thermal ageing/degradation and creep behavior of PEKK and c/PEKK composites at 200 degrees c, above the glass transition temperature (which is close to 160 degrees c). Ageing tests were carried out at 200 degrees c, under 5 bar of oxygen conditioned atmosphere. DSc scans and DMA tests were carried out. Tests results discussion were supported by indentation tests and image analysis of the aged specimen cross-section. coupled oxidation-thermomechanical-creep tests were carried out on c/PEKK samples at 200 degrees c under a 5 bar O2 environment. The resulting strain response was compared to creep tests carried out on c/PEKK samples at 200 degrees c under air at similar creep stress. Such comparison allowed to investigate the presence of degradation phenomena in c/PEKK samples. The analysis of X-rays mu-tomography scans allowed investigating the possible occurrence of degradation, and to discriminate between pure thermal and thermomechanical coupling with degradation phenomena.

关键词： PEKK c PEKK Degradation Ageing Ageing creep coupling

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