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The suppression of chain transfer reactions to produce high-molecular-weight polymers is a long-standing issue in catalytic polymerization, especially in nickel-mediated olefin polymerization. Installing sterically hindered ligands into nickel catalysts has become a general principle for producing high-molecular-weight polyolefins, which are globally important plastics. Herein, we report a new concept for preparing ultrahigh-molecular-weight polyethylene (UHMWPE) using an extremely simple nickel catalyst. Bis(o-iminobenzosemiquinonato)nickel precatalysts derived from sterically open and redox-active noninnocent o-iminobenzoquinone ligands are easily prepared from commercially available compounds, which are air-stable and highly soluble. Activation at 20- or 50-fold of Et2AlCl enables the nickel precatalysts to produce UHMWPEs (Mnup to 4,211 kDa) under ambient conditions. In particular, functionalized UHMWPEs are accessible at only 1 bar. Experimental evidence proposes the formation of a six-coordinate octahedral nickel active species and rules out the classical four-coordinate square-planar nickel active species. Density functional theory calculations further indicate the suppression of chain transfer by this unprecedented nickel platform with sterically open ligands.

The new generation of synthetic aperture radar (SAR) satellites is serving our long-standing demand for high-resolution crustal deformation over various scales. However, the reliability of interferometric SAR (InSAR) measurements is still limited by varying tropospheric conditions between acquisitions, especially when mapping slow-deforming interseismic deformation. We propose here a new phase-based approach for mapping interseismic deformation using short-period interferograms. Our method formulates the InSAR phase after topographic correction as the sum of three components: 1) spatiotemporally varied turbulent tropospheric phase; 2) topography-correlated stratified tropospheric phase; and 3) interseismic-related deformation assumed to be accumulated at a constant rate. We simultaneously solve for the parameters in the model to avoid overestimating the tropospheric phases, especially when interseismic deformation and tropospheric delays are both coupled with elevation in space. Synthetic tests and practical applications to the easternmost Altyn Tagh fault demonstrate that the new method can effectively recover the small-amplitude interseismic deformation caused by fault motion even when the interferograms are dominated by strong tropospheric delays.

A resonant cavity based on the TM010mode is an effective tool for noninvasive beam characterization. This technique has the advantages of a high signal-to-noise ratio, compact structure, and is related to multiple parameters compared with other beam monitors. In this study, high-precision measurements of the bunch charge, arrival time, bunch length, and energy parameters based on the TM010mode are discussed. A cavity beam arrival time monitor (BAM) utilizing a phase cavity has been widely used in many facilities. Regarding bunch-length measurements, the influence of the beam energy, beam offset, and longitudinal spectrum on the TM010mode are carefully considered to reduce errors, and the theoretical resolution of two cavities with different frequencies is analyzed. Owing to the dependence of the beam velocity of the beam loss factor, this method can also be used for the detection low beam energy using two cavities with the same frequency but different cavity lengths. A set of three cavities with different lengths and frequencies of 1.902 and 11.424 GHz is presented for measuring the four aforementioned parameters.

A scandium dication active species [(IPr)Sc(μ-CH2SiMe3)(μ-CH2CHMe2)AliBu2]2+[B(C6F5)4]2–(IPr = (2,6-C6H3iPr2NCH)2C) in situgenerated from the reaction of an N-heterocyclic carbene-ligated scandium trialkyl complex (IPr)Sc(CH2SiMe3)3(2) with 1–3 equiv of cocatalyst [Ph3C][B(C6F5)4] and an excess of AliBu3exhibits unprecedentedly high activity (up to 2.2 × 106g·molSc–1·h–1) and syndiotactic selectivity (rrrr> 99%) in the polymerization of o-methoxystyrene (oMOS) and its silyloxy- or fluorine-substituted derivatives, affording syndiotactic poly(oMOS)s and their silyloxy or fluorine-substituted derivatives with ultrahigh molecular weight (Mnup to 4.6 × 106) and moderate molecular weight distributions (Mw/Mn= 1.37–2.21) unavailable by the traditional catalysts. Based on in situNMR spectroscopy, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) spectroscopy, and density functional theory (DFT) calculations, a plausible coordination polymerization mechanism has been proposed for the syndiotactic polymerization of oMOS by such a Sc dication active species.

To investigate how the micro-mechanism of multi-component gas injection affects the process of retrieving methane, a combination of density functional theory and molecular dynamics simulation method has been conducted under different gas injection ratios of CO2and N2. The results of DFT demonstrate that the adsorption energy of the gas molecules over bituminous coal fragment are in order of CO2> CH4> N2. Independent gradient model analyses show that the Van der Waals interactions are the dominant force contributing to these three adsorption behaviors. To gain further insight into the influence of functional groups on CH4adsorption, the radial distribution function analyses have been performed. It was found that oxygen-containing functional groups have a substantial impact on the adsorption of CH4on coal molecules. Among these, CH4preferentially adsorb around the hydroxyl group of coal molecule. Moreover, density profiles of the three gas molecules within nanopores demonstrate that CO2molecules cause CH4molecules to desorb by molecular swapping. In contrast, N2slows down CH4adsorption spontaneity by lowering CH4partial pressure. Furthermore, it should be noted that increasing the proportion of CO2in the gas mixture system can significantly improve the displacement efficiency of CH4. Conversely, the diffusion coefficient becomes small. The microscopic mechanism revealed in the present work helps us gain a better understanding of gas displacement processes, which provides new insights for optimizing gas injection compositions for field applications.

Under acid leaching conditions, studies was discussed that the impacts of reductant type and amount on leaching rate of manganese by using three groups of glucose - hydrogen peroxide, cellulose - hydrogen peroxide and glucose - cellulose as composite reductants. The results indicate that compound reductant is able to improve the leaching rate of manganese easily. With the optimal reductant group, leaching rate of manganese can be more than 97%.

This study discussed the effects on leaching rate of from low-grade manganese ore using three reductants (Hydrogen peroxide, Glucose, Cellulose). The results showed: great increase of extracting rate can be obtained in the process of leaching by adding a small amount of reductant. the leaching rate of two valence manganese can reach a maximum of 90.76%, using hydrogen peroxide as the reductant.

In this paper, the study of leaching mechanism from low-grade manganese ores by using ternary complex reductant of hydrogen peroxide, glucose and cellulose was discussed. Quantitative and qualitative analysis were conducted about original manganese and manganese slag by XRD and FTIR. XRD quantitative analysis showed that manganese content in manganese ore is about 11%; The FTIR spectra qualitatively analyzed that part broken of the C=C bond in the manganese samples leads to divalent manganese be released.

Three major subduction earthquakes occurred on March 20, 2012 (Mw 7.4), February 16, 2018 (Mw 7.2), and June 23, 2020 (Mw 7.4) in the southwestern coast of Mexico, which caused fatalities, casualties, considerable damage, and raised safety concerns about future seismic hazards. We use satellite geodetic observations to invert for the slip distributions of the three events and then investigate their interactions. Coulomb Failure Stress (CFS) induced by their slip both on surrounding thrust and normal faults are calculated. The positive CFS changes, along with the spatial‐temporal seismicity evolution, approximate earthquake recurrence rate and interseismic coupling, collectively indicate an increased possibility of a near‐future rupture around the areas between the 2018 and 2020 events in Oaxaca. Furthermore, there is a lowered chance of shallow coastal or offshore normal earthquakes but an increased chance of inland normal ruptures. Large earthquakes result in stress changes, which can induce or retard regional seismic activity or even trigger other earthquakes. Therefore, understanding historical and recent earthquakes and their associated stress changes are crucial in the evaluation of future seismic hazards. One of the most popular and intuitive ways to relate past and future events is to calculate the Coulomb stress changes during an earthquake and a failure criterion can be established by considering the geometry of nearby faults and the stress changes induced by past events. This requires a detailed knowledge of the amount and direction of slip by which the main fault has slipped during its past ruptures. In this study, we use geodetic surface displacement measurements to invert for the slip distribution and the interactions of three subsequent subduction earthquakes in the southwestern coast of Mexico. We then evaluate the future seismic hazard of the region by considering Coulomb failure stress changes, spatial‐temporal regional seismic activities, historic earthquake records and approximate earthquake recurrence rate. The results show increased chances of a near‐future reverse rupture around Santa Catarina Juquila, Oaxaca and inland normal ruptures, but a lowered chance of shallow coastal or offshore normal ruptures. Slip distribution and interactions of three recent subduction earthquakes in Mexico revealed from radar observationsIncreased probability of a near‐future major earthquake around areas between the 2018 and 2020 events in OaxacaLowered chance of shallow coastal or offshore normal earthquakes but increased chance of inland normal ruptures Slip distribution and interactions of three recent subduction earthquakes in Mexico revealed from radar observations Increased probability of a near‐future major earthquake around areas between the 2018 and 2020 events in Oaxaca Lowered chance of shallow coastal or offshore normal earthquakes but increased chance of inland normal ruptures