mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Study on durability of Pt supported on graphitized carbon under simulated start-up/shut-down conditions for polymer electrolyte membrane fuel cells

The primary issue for the commercialization of proton exchange membrane fuel cell (PEMFC) is the carbon corrosion of support under start-up/shut-down conditions. In this study, we employ the nanostructured graphitized carbon induced by heat-treatment. The degree of graphitization starts to increase between 900 and 1300 °C as evidenced by the change of specific surface area, interlayer spacing, and I_D / I_G value. Pt nanoparticles are deposited on fresh carbon black (Pt/CB) and carbon heat-treated at 1700 °C (Pt/HCB17) with similar particle size and distribution. Electrochemical characterization demonstrates that the Pt/HCB17 shows higher activity than the Pt/CB due to the inefficient microporous structure of amorphous carbon for the oxygen reduction reaction. An accelerating potential cycle between 1.0 and 1.5 V for the carbon corrosion is applied to examine durability at a single cell under the practical start-up/shutdown conditions. The Pt/HCB17 catalyst shows remarkable durability after 30 0 0 potential cycles. The Pt/HCB17 catalyst exhibits a peak power density gain of 3%, while the Pt/CB catalyst shows 65% loss of the initial peak power density. As well, electrochemical surface area and mass activity of Pt/HCB17 catalyst are even more stable than those of the Pt/CB catalyst. Consequently, the high degree of graphitization is essential for the durability of fuel cells in practical start-up/shut-down conditions due to enhancing the strong interaction of Pt and π -bonds in graphitized carbon.
A new approach for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid without using transition metal catalysts

The organic compound 2,5-furandicarboxylic acid (FDCA) has been identified by the US Department of Energy (DOE) as a valuable platform chemical for a wide range of industrial applications. Currently, the most popular route for FDCA synthesis is reported to be the oxidation of 5-hydroxymethylfurfural (HMF) by O 2 over the catalysis of noble metals (e.g., Au, Pt, Ru, and Pd). However, the high costs of noble metal catalysts remain a major barrier for producing FDCA at an industrial scale. Herein, we report a transition metal-free synthesis strategy for the oxidation of HMF to FDCA under O_2 or ambient air. A simple but unprecedented process for the aerobic oxidation of HMF was carried out in organic solvents using only bases as the promoters. According to the high performance liquid chromatography (HPLC) analysis, excellent product yield (91%) was obtained in the presence of NaOH in dimethylformamide (DMF) at room temperature (25 °C). A plausible mechanism for the NaOH-promoted aerobic oxidation of HMF in DMF is also outlined in this paper. After the reaction, the sodium salt of FDCA particles were dispersed in the reaction mixture, making it possible for product separation and solvent reuse. The new HMF oxidation approach is expected to be a practical alternative to current ones, which depend on the use of noble metal catalysts.
Graphene fiber based supercapacitors: Strategies and perspective toward high performances

Modern wearable electronics are thirsty for flexible, lightweight energy storage and supply devices. Flexible fiber-shaped supercapacitors, possess good flexibility, high power density, fast charging capability and long cycle life, becoming a promising option for wearable devices. The past decade has witnessed the emergence of graphene fiber based supercapacitors (GFSCs) as one of the most active vicinity in fiber-supercapactiors, for their excellent properties including high surface area, chemical stability, excellent electrical conductivity, lightweight and mechanical properties. In this perspective, we introduced the basic energy storage mechanisms of GFSCs, followed by the analysis in improving their overall performances, recent advances, and a conclusive discussion on the challenges and opportunities.
Two-dimensional nanosheets as building blocks to construct three-dimensional structures for lithium storage

2D nanosheets such as graphene, silicene, phosphorene, metal dichalcogenides and MXenes are emerging and promising for lithium storage due to their ultrathin nature and corresponding chemical/physical properties. However, the serious restacking and aggregation of the 2D nanosheets are still hampering their applications. To circumvent the issues of 2D nanosheets, one efficient strategy is to construct 3D structures with hierarchical porous structures, good chemical/mechanical stabilities and tunable electrical conductivities. In this review, we firstly focus on the available synthetic approaches of 3D structures from 2D nanosheets, and then summarize the relationships between the microstructures of 3D structures built from 2D nanosheets and their electrochemical behaviors for lithium storage. On the basis of above results, some challenges are briefly discussed in the perspective of the development of various functional 3D structures.
Engineering graphene for high-performance supercapacitors: Enabling role of colloidal chemistry

The high electrical conductivity and high specific surface area of graphene are traditionally regarded as the most intriguing features for its promise as the electrode material for supercapacitors. In this perspective, we highlight that from the engineering point of view, the unique colloidal chemistry of chemically functionalized graphene is the key property that has made graphene stand out as a promising nanoscale building block for constructing unique nanoporous electrodes for capacitive energy storage. We present several examples to demonstrate how the non-covalent colloidal forces between graphene sheets can be harnessed to engineer the nanostructure of graphene-based bulk electrodes for supercapacitors based on both the electrical double layer storage and the redox reaction or pseudo-capacitance mechanisms. The colloidal engineering strategy can be extended to enable other nanomaterials to achieve high energy storage performance.
Two-dimensional organic cathode materials for alkali-metal-ion batteries

With the increasing demand for large-scale battery systems in electric vehicles (EVs) and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional (2D) organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery (LIB), lithium sulfur battery (LSB), lithium air battery (LAB) and sodium ion battery (SIB) are summarized systematically, and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.
NLO QCD corrections to B_c(B_c~*) production around the Z pole at an e~+e~- collider

The production of B_c and B_c~* mesons at a Z-factory (an e~+e~- collider operating at energies around the Z pole) is calculated up to the next-to-leading order (NLO) QCD accuracy. The results show that the dependence of the total cross sections on the renormalization scale μ is suppressed by the corrections, and the NLO corrections enhance the total cross sections of B_c by 52% and of B_c~* by 33% when the renormalization scale is taken at μ = 2m_b. To observe the various behaviors of the production of the mesons B_c and B_c~*, such as the differential cross section vs. the out-going angle, the forward-backward asymmetry, and the distribution vs. the energy fraction z up to NLO QCD accuracy as well as the relevant K-factor (NLO to LO) for the production, are calculated, and it is pointed out that some of the observables obtained in the present work may be used as a specific precision test of the standard model.
Hypersonic I-shaped aerodynamic configurations

Hypersonic vehicles, which flight at Mach numbers greater than 5, will serve as a more convenient and efficient transport tool than present subsonic airplanes for long-distance journeys in future. Typically, it only takes a couple of hours from Beijing to New York at hypersonic speed. Recent interest in these vehicles has grown intensively, and various types of innovative designs have been proposed and studied. Despite entering the age of hypersonic flight, there still exist many problems to resolve [1-4]. How to design an advanced aerodynamic configuration is one of them [5].
A study on flow fields and performance of water wheel turbine using experimental and numerical analyses

In this paper, an analysis of the performance and flow fields of water wheel turbines for tidal energy extraction is carried out using experimental and numerical methods. The purpose of this work is to develop a water turbine suitable for sites, where fast and shallow surface flows are available, such as rivers or tidal currents. For both methods, the water wheel turbine is tested over a range of tip speed ratios with a differing number of rotor blades, ranging between three and twelve. The results indicate that the numerical simulation shows agreement with the experiment in most cases. Also, the water wheel turbine operates effectively at a range of small tip-speed ratios, where the highest turbine efficiency is produced. Under the same working conditions, the turbines using between six and nine blades generate a greater efficiency and cause lesser reverse flows than others when submerged in water. In contrast, the 3-bladed turbine is the least efficient design as it produces the lowest amount of energy and causes intense vibrations and noises. These noises are a result of a collision between the incoming flow of the channel and the wheel blades during the experimentation, especially at high load conditions. By adding more blades, the torque generated is improved considerably; however, the upstream and downstream depths of the turbine, in this case, are also elevated significantly. Furthermore, in the inlet region, the 3-bladed and 6-bladed turbines have a smaller shock loss and a lower resistance to the main flow from the inlet than the others. Meanwhile, it is found that the flow in the outlet region on the turbines with between nine and twelve blades is in the opposite direction to the wheel's rotation, significantly obstructing the main flow from the inlet.
Microstructure and mechanical properties of FeCoNiCr high-entropy alloy strengthened by nano-Y_2O_3 dispersion

In this manuscript, the FeCrCoNi high entropy alloy strengthened by nano-Y_2O_3 particles was synthesized via mechanical alloying and spark plasma sintering. Effects of Y_2O_3 additions on the microstructure and mechanical properties were investigated. The oxide-dispersion-strengthened (ODS) high-entropy alloy bearing 5wt% Y_2O_3 was found to have a finer grain with respect to the single-phase face-centered cubic (FCC) alloy without oxides. Consequently, the yield strength increased from 654 to 1754 MPa, and the fracture strength reached up to 2325 MPa while the plasticity decreased appreciably for the ODS high-entropy alloy. The synergic effects of grain size hardening and particle strengthening on mechanical properties of the ODS HEA were discussed. This finding indicates that the addition of nano-scaled oxides is an effective and feasible approach to designing HEAs with superior mechanical properties.
The 5.5 cal ka BP climate event, population growth, circumscription and the emergence of the earliest complex societies in China

The emergence of complex society is a milestone in the history of human society evolution. China is one of the few regions in the world where the earliest complex society appeared; however, its driving mechanisms remain unresolved. On the base of available evidence from both archaeology and Holocene climate, in combination with agency theory, this study attempts to address the driving mechanisms for the simultaneous emergence of complex societies in multiple areas of China around 5.5 cal ka BP. It is hypothesized that three factors, including climate change, population growth, and circumscription, jointly act and cause regional population-resource imbalance and trigger inter-group conflicts and wars. Such competitions provide the opportunity for some power-pursuing agents to break the restriction of social leveling mechanism and to become the centralized decision-making leaders, which further lead to the emergence of incipient large-scale complex societies. Increase in extreme climate events during 6.0-5.0 cal ka BP cooling period causes frequent occurrence of resource stress and increase in the frequency of inter-group competitions, which creates conditions for the legitimation, institutionalization, and persistence of centralized leadership, and finally leads to the formation of persistent institutionalized inequity. Our research result can explain not only the process and mechanism of complex society formation, but also two phenomena which cannot be reasonably explained by previous theories, that are, why the earliest complex societies in China emerge around 5.5 cal ka BP, and why they appear simultaneously in multiple regions.
A brief introduction of cryo-EM revolution-the Nobel Prize in Chemistry 2017

Seeing is believing! Cryo-electron microscopy (cryo-EM) has greatly expanded the limit of human vision. The Nobel Prize in Chemistry 2017 was awarded to Jacques Dubochet, Joachim Frank and Richard Henderson for their development of cryo-EM. This method has revolutionized the structural study of biomolecules in the past few years. Now, scientists can routinely visualize many different kinds of biological machineries with unprecedented details.
Statistical characteristics of forest litterfall in China

Litterfall represents a major pathway of carbon and mineral transfer from vegetation to soils, and thus is an important ecological process in carbon and nutrient cycling. Annual litterfall production also influences the amount of fuel accumulated in the forests, which serves as a part of an indicator for risk from forest fire. China covers a broad climatic gradient and contains almost all major forest types of the northern hemisphere from boreal to tropical forests. However, few synthesis studies on the production of litterfall at a national scale in Chinese forests have been reported so far. This study attempted to characterize the integrated forest litterfall dataset ofChina (N=904, 1970-2014, Jia et al., 2016) to provide essential information required by regional biogeochemical cycle and fire risk models.
Preliminary analysis on the source properties and seismogenic structure of the 2017 M_s7.0 Jiuzhaigou earthquake

At GMT time 13:19, August 8, 2017, an M_s7.0 earthquake struck the Jiuzhaigou region in Sichuan Province, China, causing severe damages and casualties. To investigate the source properties, seismogenic structures, and seismic hazards, we systematically analyzed the tectonic environment, crustal velocity structure in the source region, source parameters and rupture process, Coulomb failure stress changes, and 3-D features of the rupture plane of the Jiuzhaigou earthquake. Our results indicate the following: (1) The Jiuzhaigou earthquake occurred on an unmarked fault belonging to the transition zone of the east Kunlun fault system and is located northwest of the Huya fault. (2) Both the mainshock and aftershock rupture zones are located in a region where crustal seismic velocity changes dramatically. Southeast to the source region, shear wave velocity at the middle to lower crust is significantly low, but it rapidly increases northeastward and lies close to the background velocity across the rupture fault. (3) The aftershock zone is narrow and distributes along the northwest-southeast trend, and most aftershocks occur within a depth range of 5-20 km. (4) The focal mechanism of the Jiuzhaigou earthquake indicates a left-lateral strike-slip fault, with strike, dip, and rake angles of 152°, 74° and 8°, respectively. The hypocenter depth measures 20 km, whereas the centroid depth is about 6 km. The co-seismic rupture mainly concentrates at depths of 3-13 km, with a moment magnitude (M_w) of 6.5. (5) The co-seismic rupture also strengthens the Coulomb failure stress at the two ends of the rupture fault and the east segment of the Tazang fault. Aftershocks relocation results together with geological surveys indicate that the causative fault is a near vertical fault with notable spatial variations: dip angle varies within 66°-89° from northwest to southeast and the average dip angle measures ~84°. The results of this work are of fundamental importance for further studies on the source characteristics, tectonic environment, and seismic hazard evaluation of the Jiuzhaigou earthquake.
Celastrol specifically inhibits the activation of NLRP3 inflammasome

Inflammasomes are vital components of the innate immune system that survey microbial infections or sterile challenges in the cytosol (de Zoete et al.,2014). A typical inflammasome is composed of a sensor protein such as NOD like receptor (NLR) or AIM2 like receptor (ALR), the adaptor protein apoptosis associated speck-forming complex containing CARD (ASC),and the effector protein pro-caspase-1 (Vanaja et al., 2015). Assembly of inflammasome leads to the maturation of caspase-1, which cleaves pro-IL-lβ and pro-IL-18 to their mature forms, and results in pyroptosis (Shi et al., 2017). A number of inflammasomes have been identified so far, and the NLRP3 inflammasome is the most extensively studied one due to its connection to many different diseases (Guo et al., 2015). As such, more and more chemical inhibitors have been developed to control the function of NLRP3 inflammasome (Shao et al., 2015). Natural compounds derived from food or traditional anti-inflammatory medicine have been implied targeting inflammasomes (Chuang et al., 2014). The Chinese herb Thunder God Vine (Tripterygium wilfordii Hook F.) has been recognized to be suppressive for inflammation and is effective in treating various autoimmune diseases (Kannaiyan et al., 2011; Salminen et al., 2010; Yu et al., 2010). However, whether Thunder God Vine inhibits inflammasomes has not been investigated.
POSS-embedded supramolecular hyperbranched polymers constructed from a 1→7 branching monomer with controllable morphology transitions

The research on the supramolecular hyperbranched polymers (SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers (POSS-SHPs) with varied morphology and size by controlling monomer concentration and mixed solvents. The SHPs formations can further transfer into the core-shell structured micelles by addition of competitive guests based on the double supramolecular driving forces.
Total chemical and semisynthetic approaches for the preparation of ubiquitinated proteins and their applications

Protein ubiquitination is an important post-translational modification (PTM) in eukaryotic organisms that regulates a variety of cellular processes, such as protein degradation, signal transduction, apoptosis, and DNA damage tolerance. To decipher mechanistically the diverse biological functions of ubiquitination, homogeneous ubiquitinated proteins are greatly needed. Although direct isolation from cell source and in vitro enzymatic methods can be used to produce such proteins, these methods often suffer from problems of low yield or heterogeneous products. Comparably, total chemical and semisynthetic approaches offer good alternatives to produce the ubiquitinated proteins with high purity and selectivity. This review summarizes the recent developments of protein ubiquitination strategies and the use of the synthesized proteins to help garner structural and functional insight into the inner workings of the ubiquitin system.
A reversible acid-base fluorescent switch based on molecular cocrystal of 4-[2-4-quinolinyl)vinyl]phenol and tetrafluoroterephthalic acid

Photoactive cocrystal materials have received growing research interest in construction of photofunctional systems owing to the crucial roles in modifying the photo-related properties of molecular solids, based on the non-bonding interactions between self-assembly units. Herein, we report tunable luminescence and acid-base stimuli-responsive properties of a cocrystal assembled by 4-[2-(4-quinolinyl)vinyl]phenol (qv) and tetrafluoroterephthalic acid (a). The luminescent properties (such as wavelength, quantum yield and fluorescence lifetime) of qv.a changed obviously relative to the pristine qv, due to the proton transfer and the alternation of molecular arrangement within two-component crystalline material. The photoemission intensity of qv.a underwent from weak to strong upon HCl gas fuming, and the corresponding wavelength changed from 517 nm to 597 nm, which can be reversibly transferred after exposed in NH_3. Such luminescent switching behavior may provide an effective way to develop new types of photoactive stimuli-responsive materials and optical sensors.
Generalized Markov interacting branching processes

We consider a very general interacting branching process which includes most of the important interacting branching models considered so far. After obtaining some key preliminary results, we first obtain some elegant conditions regarding regularity and uniqueness. Then the extinction vector is obtained which is very easy to be calculated. The mean extinction time and the conditional mean extinction time are revealed. The mean explosion time and the total mean life time of the processes are also investigated and resolved.
Glass transition: from interaction potential changes to the corresponding structural and relaxation responses along the path of reaching the final equilibrium

Glass transition involves a many-body interaction and relaxation process. The split of relaxation spectrum and the extremely slow dynamics bring into considerations of non-linearity and non-equilibrium. Some of our recent findings in two measurable colloidal systems are reviewed, one with a simple attractive interparticle potential and the other with a competitive (repulsive vs. attractive) inter-particle interaction. With an approach from interaction potential changes to the corresponding structural and relaxation responses, along the path of reaching the final equilibrium, we illustrate some interesting physics in glass formation process. Also, some reviews on the popular glass transition theories are made to remind readers to avoid artifacts and misinterpretations.