The Chang 7 oil group in the Ordos Basin has the characteristics of a tight lithology, a low formation pressure coefficient and strong reservoir heterogeneity. To better determine reasonable ...developmental technical countermeasures, oiliness, seepage capacity, and compressibility evaluations are combined. Using a combination of field practice and laboratory experiments, six types of sweetness classification evaluation parameters are screened: oil saturation, longitudinal oil layer structure coefficient, average pore throat radius, gas-oil ratio, brittleness index, and minimum horizontal principal stress. By combining the relationships among variables with the initial production from directional wells, the gray correlation method is used to quantify the weights of the contributions of evaluation parameters to production. On this basis, using the difference method for the curve slope, a sweetness evaluation and classification method for the Chang 7 oil group is constructed, and it solves the difficult problem of quality difference classification for the Chang 7 oil group and provides a reference basis for the optimal design of well patterns and fracturing reconstruction parameters.
Complexes 1 and 2 are water-soluble and are pretty stable in dark. However, they exhibit good CO release ability upon exposure to UV and visible light. The CO releasing rate can be adjusted by the ...wavelength of irradiation light. Furthermore, they can inhibit the secretion of NO and TNF-α in LPS-stimulated RAW264.7 macrophages.
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•Complexes 1 and 2 exhibit good CO release ability upon exposure to UV/visible light.•The CO releasing rate depends on the wavelength of irradiation light.•Complexes 1 and 2 possess high water-solubility.•Complexes 1 and 2 can inhibit the secretion of NO and TNF-α.
By reactions of MnBr(CO)5 with 2,2′-bipyridyl-4,4′-dicarboxylic acid and 2,5-pyridinedicarboxylic acid, respectively, we obtained two new Mn-CORMs, Mn(CO)3(H2O)(HBPDC) (1) and Mn(CO)3(CH3CN)(HPYDC)·CH3CN (2). Complexes 1 and 2 are stable in the absence of light, but they exhibit good CO release ability upon exposure to UV and visible light (blue and green). The CO releasing rate depends on the wavelength of irradiation light, i.e., UV > blue > green, which may make them act as visible light regulated CORMs. It is noteworthy that complexes 1 and 2 possess high water-solubility. TD-DFT studies of complexes 1 and 2 reveal that the metal-to-ligand charge-transfer (MLCT) may be responsible for their CO releasing behaviors triggered by UV and visible light. The cellular viability and anti-inflammatory activities evaluation show that complexes 1 and 2 can inhibit the secretion of NO and TNF-α in LPS-stimulated RAW264.7 macrophages with fine biological compatibility and without apparent cytotoxicity. Furthermore, during the synthesis of complexes 1 and 2, when the pH of solution is hinger than 7, complexes {Mn(BPDC)}n (1A) and Mn(H2O)2(HPYDC)2 (2A) are obtained. Complex 1A is a new 3D Mn-MOF and complex 2A is a zero-dimensional mononuclear compound, which are all without CO ligand.
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•Influence of storage temperature and duration on pristine Li-rich layered cathode is investigated.•Room temperature storage has little influence on cycling stability of pristine ...Li-rich layered oxide.•Cycling stability is highly dependent on duration when stored at high temperature in pristine state.•Deteriorated cycling stability is attributed to surface reaction.•An approach for predicting electrochemical performance is indicated.
Lithium-ion batteries always suffer from serious capability decay, especially when stored at high temperature and/or for prolonged duration. In this work, electrochemical performance for Li-rich layered oxides Li1.20Mn0.54Co0.13Ni0.13O2 was systematically investigated as a function of temperature and duration. Plenty of techniques like SEM, EDS, EIS, ARC, Raman, XRD, and XPS were utilized to characterize the structures, valence states, compositions, particle sizes, and morphologies of the layered oxides with varying temperature and duration. The results reveal that room temperature storage may alter surface kinetics, but hardly influence the electrochemical performance. While in the case of high temperature storage in pristine state, cycling stability is highly dependent on the storage duration. The degradation mechanism at high temperature storage with prolonged duration is demonstrated to be the accumulation of surface species like LiF/LixPFyOz initiated by the strong reactions between LiPF6 electrolyte and electrode. The results reported here may shed light on predicting electrochemical performance by surface analysis and also provide vital hints on enhancing the high-temperature storage stability of Li-rich layered oxides.
An ESBL, carbapenemase- and MCR-1-producing
ST648 strain was isolated from the urine sample of a patient in a Chinese tertiary hospital in 2016.
The strain was fully sequenced by GridION X5 platform ...of Oxford Nanopore Technology.
The sequence analysis showed that the extended-spectrum β-lactamases CTX-M-65 and OXA-1, the carbapenemase NDM-5, the MCR-1 were encoded, respectively, by three different resistance plasmids. The pE648CTX-M-65-carrying
was a novel conjugative plasmid belonging to IncHI2 type; except for the
, it also carried resistance genes
,
and
. Besides, an IncX4 plasmid pE648MCR-1-carrying
and an IncX3 plasmid pE648NDM-5-carrying
were also identified.
The three transferable resistance plasmids coexisting in the
ST648 isolate indicated the high risk to disseminate the extensively-drug-resistance among Enterobacteriaceae.
In order to meet the requirements of the ideal kinematics characteristics of the driven gear, a new kind of uniform-variable non-circular gear is proposed. According to the ideal speed curve and ...acceleration curve, the concept of the uniform-variable non-circular gear is analyzed. The pitch curve equations are derived and the formulas for calculating the gear’s section length and center distance are established. A design procedure is developed and a simplified derivation of the mathematical model is presented. A few characteristics, such as pressure angles, the undercut and the contact ratio, of this new drive are analyzed. The results confirm that the proposed design method is more flexible to control the shape of the pitch curves by changing the parameters of the given speed curve and acceleration curve.
Understanding the nature of pristine surface associated with lithium- and manganese-rich cathodes is the key to optimizing the electrochemical performance for Li-ion batteries. In this work, ...Li1.2Mn0.54Ni0.13Co0.13O2 cathodes with phase and element homogeneity were synthesized by a facile hydroxide co-precipitation strategy. Two routes of adjusting lithium content and post-treatment were applied to tune the surface structure of pristine samples. It is found that the sample with 5 wt%-excess lithium and after post-treatment exhibits excellent capacity and rate-capability: delivering initial discharge capacities of 254 mAh/g at current densities of 100mA/g, 200 mAh/g at 1000mA/g, and 142 mAh/g at 4000mA/g. The capacity of this cathode at 4A/g thereby remains 55 percentage of the discharge capacity at 100mA/g. The reason for the better performance of this cathode was attributed to the removal of surficial amorphous Li2CO3 layer, as revealed by the detailed analyses of transition electron micrograph and X-ray photoelectron spectrum. The amorphous layer was demonstrated by electrochemical impedance to show a block effect on increasing the interfacial resistance. This work may shed light on the importance of pristine surface and provide a hint for searching cathodes of high-energy Li-ions batteries with excellent capacity and rate properties.
Developing energy storage equipments that can work at very high charge–discharge rate is crucial, but highly challenging for more efficient use of energy. From the perspective of chemistry, high-rate ...property of Li-ion batteries can only be achieved by significantly improving the kinetics of lithium ions and electrons in electrode. Here, we for the first time report on a simple method to resolve kinetics problems of ultrafast charging–discharging Li-ion batteries by fabrication of layered LiMO2 (M = Mn, Co, Ni) hexagonal sheet exposing with facets {101}. The synthetic procedure of hexagonal sheets is proceeded via a simple PVP-assisted co-precipitation, which is followed by a heat treatment. All hexagonal sheets LiMnxCoyNizO2 were demonstrated to deliver a superior excellent rate capability and outstanding cycle stability at high current density of 3000 mA g−1 and under a high cutoff voltage of 4.4 V. The discharge capacity for the composition LiMn0.075Co0.775Ni0.15O2 at an ultrahigh charge–discharge rate of 10,000 mA g−1 is almost as large as that for LiMn2O4 and commercial LiFePO4 at low rate of 1C. The methodology reported here to resolve the kinetic problems of lithium ions and electrons in electrodes may have many implications that would help scientists to find more high-rate lithium-ion batteries for powering electric vehicles and other applications.
LiMO2 (M = Mn, Co, Ni) hexagonal sheets exposed with facets {101} were first fabricated for ultrafast charging–discharging Li-ion batteries. Display omitted
•Layered LiMO2 hexagonal sheets exposed with (101) facets were successfully synthesized.•The transport distance of lithium ions in hexagonal sheets is greatly shortened.•Layered LiMO2 hexagonal sheets can work at ultra-high charge–discharge rates.
Developing new methods to synthesize intermetallics is one of the most critical issues for the discovery and application of multifunctional metal materials; however, the synthesis of Sn‐containing ...intermetallics is challenging. In this work, we demonstrated for the first time that a self‐disproportionation‐induced in situ process produces cavernous Sn−Cu intermetallics (Cu3Sn and Cu6Sn5). The successful synthesis is realized by introducing inorganic metal salts (SnCl2⋅2 H2O) to NaOH aqueous solution to form an intermediate product of reductant (Na2SnO2) and by employing steam pressures that enhance the reduction ability. Distinct from the traditional in situ reduction, the current reduction process avoided the uncontrolled phase composition and excessive use of organic regents. An insight into the mechanism was revealed for the Sn−Cu case. Moreover, this method could be extended to other Sn‐containing materials (Sn−Co, Sn−Ni). All these intermetallics were attempted in the catalytic effect on thermal decompositions of ammonium perchlorate. It is demonstrated that Cu3Sn showed an outstanding catalytic performance. The superior property might be primarily originated from the intrinsic chemical compositions and cavernous morphology as well. We supposed that this smart solution reduction methodology reported here would provide a new recognition for the reduction reaction, and its modified strategy may be applied to the synthesis of other metals, intermetallics as well as some unknown materials.
Smart solution: A new self‐disproportionation‐induced in situ reduction strategy for the synthesis of Sn‐containing intermetallic compounds was proposed for the first time. Using this strategy, polyhedron Sn−Co, popcorn‐like Sn−Ni and cavernous Cu−Sn intermetallic compounds were synthesized (see figure).
Background: An ESBL, carbapenemase- and MCR-1-producing Escherichia coli ST648 strain was isolated from the urine sample of a patient in a Chinese tertiary hospital in 2016. Methods: The strain was ...fully sequenced by GridION X5 platform of Oxford Nanopore Technology. Results: The sequence analysis showed that the extended-spectrum β-lactamases CTX-M-65 and OXA-1, the carbapenemase NDM-5, the MCR-1 were encoded, respectively, by three different resistance plasmids. The pE648CTX-M-65-carrying blaCTX-M-65 was a novel conjugative plasmid belonging to IncHI2 type; except for the blaCTX-M-65, it also carried resistance genes ble, floR, sul1, aph(4)-Ia, aac(3)-VI, aac(6ʹ)-II, blaOXA-1, catB, arr3 and tetA. Besides, an IncX4 plasmid pE648MCR-1-carrying mcr-1 and an IncX3 plasmid pE648NDM-5-carrying blaNDM-5 were also identified. Conclusion: The three transferable resistance plasmids coexisting in the E. coli ST648 isolate indicated the high risk to disseminate the extensively-drug-resistance among Enterobacteriaceae.
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