Atomically Dispersed Pd on Nanodiamond/Graphene Hybrid for Selective Hydrogenation of Acetylene

An atomically dispersed palladium (Pd) catalyst supported onto a defective nanodiamond-graphene (ND@G) is reported here for selective hydrogenation of acetylene in the presence of abundant ethylene. The catalyst exhibits remarkable performance for the selective conversion of acetylene to ethylene: high conversion (100%), ethylene selectivity (90%), and good stability (i.e., steady for at least 30 hours). The unique struc-ture of the catalyst (i.e., atomically dispersion of Pd atoms on graphene through Pd-C bond anchoring) ensure the facile desorption of ethylene against the over-hydrogenation of ethylene to undesired ethane, which is the key for the outstanding selectivity of the catalyst

Anchoring Cu 1 species over nanodiamond-graphene for semi-hydrogenation of acetylene

The design of cheap, non-toxic, and earth-abundant transition metal catalysts for selective hydrogenation of alkynes remains a challenge in both industry and academia. Here, we report a new atomically dispersed copper (Cu) catalyst supported on a defective nanodiamondgraphene (ND@G), which exhibits excellent catalytic performance for the selective conversion of acetylene to ethylene, i.e., with high conversion (95%), high selectivity (98%), and good stability (for more than 60 h). The unique structural feature of the Cu atoms anchored over graphene through Cu-C bonds ensures the effective activation of acetylene and easy desorption of ethylene, which is the key for the outstanding activity and selectivity of the catalyst

Tin Assisted Fully Exposed Platinum Clusters Stabilized on Defect-Rich Graphene for Dehydrogenation Reaction

Tin assisted fully exposed Pt clusters are fabricated on the core-shell nanodiamond@graphene (ND@G) hybrid support (a-PtSn/ND@G). The obtained atomically dispersed Pt clusters, with an average Pt atom number of 3, were anchored over the ND@Gsupport by the assistance of Sn atoms as a partition agent and through the Pt-C bond between Pt clusters and defect-rich graphene nanoshell. The atomically dispersed Pt clusters guaranteed a full metal availability to the reactants, a high thermal stability, and an optimized adsorption/desorption behavior. It inhibits the side reactions and enhances catalytic performance in direct dehydrogenation of n-butane at a low temperature of 450 °C, leading to \u3e98% selectivity toward olefin products, and the turnover frequency (TOF) of a-PtSn/ND@G is approximately 3.9 times higher than that of the traditional Pt3Sn alloy catalyst supported on Al2O3 (Pt3Sn/Al2O3)

EXPERIMENTAL STUDY ON RHEOLOGICAL BEHAVIOR OF022Cr18Ni14Mo2 STAINLESS STEEL AT HIGH TEMPERATURE AND HIGH STRAIN RATE

To explore the influence of external temperature and loading rate on itsrheological behavior and mechanism, the dynamic impact compression test was conducted on 022 Cr18 Ni14 Mo2 stainless steel by using the split Hopkinson compression bar test platformat at 2 000 s-1～5 000 s-1 and 25℃～400℃.The results show that the flow stress, strain rate sensitivity, strain hardening and temperature sensitivity of the sample are closely related to strain, temperature and strain rate. At a constant temperature, the flow stress, strain hardening effect, and strain rate sensitivity increase with the increase of strain rate.At a constant strain rate, the temperature sensitivity increases with the increase of temperature, and the sample exhibits a significant thermal softening effect. The strain rate sensitivity and strain hardening effect appear to weaken with increasing temperature. In addition, the microstructure observation by scanning electron microscope（SEM） shows that deformation twins are mainly present in the grains, and a deformation zone with positioning or stacking faults is present in the grains. Under high strain rate or low temperature conditions, the number of deformation zone in the grain is more. The deformation twins within the grains help to adjust the degree of deformation between the grains and improve the uniformity of sample deformation at high strain rate

Research Progress of Tie-Generative Mechanism in Network Based on ERGM

The research on the tie-generative mechanism in network is conductive to explore the factors affecting network evolution and provide theoretical supports and decision-making suggestions for promoting (restraining) the formation (disappearance) of network edges. Based on the analysis of the current situation and development trend of ERGM from 2015 to 2020, this paper presents the research progress and limitations of ERGM. It has made good progress in the fields of network dynamic evolution mechanism, capturing network node heterogeneity, multi-layer network formation mechanism and Research on large (small) scale network formation mechanism. However, it must be admitted that the problems such as extending ERGM to obtain connection weighted information, modeling the heterogeneity of nodes in the network, detecting the multicollinearity that may exist in ERGM, studying the dynamic evolution mechanism of multi-layer network and using ERGM to deal with network missing data have not been well solved, waiting for further exploration

Freezing-tolerant and robust gelatin-based supramolecular conductive hydrogels with double-network structure for wearable sensors

It is significant to design stretchable conductive hydrogels with high integrated mechanical and excellent anti-freezing performances for broadening their application fields. Herein, a freezing-tolerant and robust poly(N-hydroxymethyl acrylamide)/gelatin/glycerol supramolecular conductive hydrogel with double networks is synthesized via an one-pot method, where poly(N-hydroxymethyl acrylamide) can self-cross-link, and also interact with gelatin. Glycerol endows the conductive hydrogel with anti-freezing property in mechanics and electricity, and can also interact with poly(N-hydroxymethyl acrylamide) and gelatin to further enhance mechanical properties. Under optimal conditions, the conductive hydrogel exhibits high strength, super extensibility, rapid self-recovery, excellent fatigue resistance and high ionic conductivity. It possesses temperature insensitivity of mechanical properties and weak dependence of electrical behaviors on temperature. Furthermore, it exhibits excellent anti-freezing resistance response to strain, and can as sensor detect human activities. Thus, this work provides a simple and promising strategy for designing stretchable conductive gels with integrated high performances aiming for wearable intelligent electronics

Methods of Conserving and Managing Cultural Heritage in Classical Chinese Royal Gardens Based on 3D Digitalization

In this study, we aimed to implement information obtained and refined from garden elements in heritage conservation, monitoring, and management to precisely construct an information model of classical Chinese gardens, including information on the garden entity, garden space, and garden attributes, etc., and to improve the management efficiency of classical Chinese royal gardens. Three-dimensional laser scanning technology and point cloud information were used to accurately collect and process digital information from classical Chinese royal gardens. After classifying and processing the point cloud data, correlations therein could be further assessed and used to greatly improve the accuracy and management efficiency of spatial information. To provide a more convenient solution for the subsequent conservation and management of landscape heritage, a method for establishing a three-dimensional digital information database and a full life-cycle application management platform for classical Chinese royal gardens is proposed in this research. This method has broad applications for the digital conservation and management of cultural heritage

De novo variants in the PABP domain of PABPC1 lead to developmental delay

Purpose: The study aimed to investigate the role of PABPC1 in developmental delay (DD). Methods: Children were examined by geneticists and pediatricians. Variants were identified using exome sequencing and standard downstream bioinformatics pipelines. We performed in silico molecular modeling and coimmunoprecipitation to test if the variants affect the interaction between PABPC1 and PAIP2. We performed in utero electroporation of mouse embryo brains to enlighten the function of PABPC1. Results: We describe 4 probands with an overlapping phenotype of DD, expressive speech delay, and autistic features and heterozygous de novo variants that cluster in the PABP domain of PABPC1. Further symptoms were seizures and behavioral disorders. Molecular modeling predicted that the variants are pathogenic and would lead to decreased binding affinity to messenger RNA metabolism-related proteins, such as PAIP2. Coimmunoprecipitation confirmed this because it showed a significant weakening of the interaction between mutant PABPC1 and PAIP2. Electroporation of mouse embryo brains showed that Pabpc1 knockdown decreases the proliferation of neural progenitor cells. Wild-type Pabpc1 could rescue this disturbance, whereas 3 of the 4 variants did not. Conclusion: Pathogenic variants in the PABP domain lead to DD, possibly because of interference with the translation initiation and subsequently an impaired neurogenesis in cortical development

De novo variants in the PABP domain of PABPC1 lead to developmental delay

Purpose: The study aimed to investigate the role of PABPC1 in developmental delay (DD). Methods: Children were examined by geneticists and pediatricians. Variants were identified using exome sequencing and standard downstream bioinformatics pipelines. We performed in silico molecular modeling and coimmunoprecipitation to test if the variants affect the interaction between PABPC1 and PAIP2. We performed in utero electroporation of mouse embryo brains to enlighten the function of PABPC1. Results: We describe 4 probands with an overlapping phenotype of DD, expressive speech delay, and autistic features and heterozygous de novo variants that cluster in the PABP domain of PABPC1. Further symptoms were seizures and behavioral disorders. Molecular modeling predicted that the variants are pathogenic and would lead to decreased binding affinity to messenger RNA metabolism-related proteins, such as PAIP2. Coimmunoprecipitation confirmed this because it showed a significant weakening of the interaction between mutant PABPC1 and PAIP2. Electroporation of mouse embryo brains showed that Pabpc1 knockdown decreases the proliferation of neural progenitor cells. Wild-type Pabpc1 could rescue this disturbance, whereas 3 of the 4 variants did not. Conclusion: Pathogenic variants in the PABP domain lead to DD, possibly because of interference with the translation initiation and subsequently an impaired neurogenesis in cortical development