A Well Productivity Model for Multi-Layered Marine and Continental Transitional Reservoirs with Complex Fracture Networks

Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.

An Integrated Control Strategy Adopting Droop Control with Virtual Inductance in Microgrid

As there exists sorts of distributed generators in microgrid, an integrated control strategy containing different control methods against corresponding generators should be applied. The strategy in this paper involves PQ control and droop control methods. The former aims at letting generators like PV output maximum power. The latter stems from inverter parallel technique and applies to controlling generators which can keep the network voltage steady to make the parallel system reach the minimum circulation point. Due to the unworthiness of droop control applied in low-voltage microgrid of which the impedance ratio is rather high, the paper adopts the droop control introducing virtual generator and virtual impedance. Based on theoretical analysis, simulation in Matlab is also implemented to verify the feasibility of the strategy.

Resilient Event-Triggered Model Predictive Control for Adaptive Cruise Control Under Sensor Attacks

Dear Editor,This letter addresses the resilient model predictive control(MPC)problems for adaptive cruise control(ACC)systems under sensor attacks.In the light of vulnerabilities of ACC systems to sensor attacks,an intrusion detection mechanism is proposed at the controller side to distinguish abnormal data.Then,the robust control gains are derived to design the terminal region constraint for MPC.

Wide-Area Delay-Dependent Adaptive Supervisory Control of Multi-machine Power System Based on Improve Free Weighting Matrix Approach

The paper demonstrates the possibility to enhance the damping of inter-area oscillations using Wide Area Measurement (WAM) based adaptive supervisory controller (ASC) which considers the wide-area signal transmission delays. The paper uses an LMI-based iterative nonlinear optimization algorithm to establish a method of designing state-feedback controllers for power systems with a time-varying delay. This method is based on the delay-dependent stabilization conditions obtained by the improved free weighting matrix (IFWM) approach. In the stabilization conditions, the upper bound of feedback signal’s transmission delays is taken into consideration. Combining theoriesof state feedback control and state observer, the ASC is designed and time-delay output feedback robust controller is realized for power system. The ASC uses the input information from Phase Measurement Units (PMUs) in the system and dispatches supplementary control signals to the available local controllers. The design of the ASC is explained in detail and its performance validated by time domain simulations on a New England test power system (NETPS).

The expression of Bcl-2 and Bax produced by sub-chronic intoxication with the cyanotoxin Microcystin-LR

Objective:We explored the role and molecular mechanism of Microcystin-LR(MC-LR) in hepatocarcinogenesis.Methods:The two-stage-medium-term theory was applied to the establishment of the animal model.The promoting effect of MC-LR on liver tumor was evaluated with the Albert γ-GT methods.During the tumor-promoting course,the effects of MC-LR on the regulation and expression of the Bcl-2 and Bax genes were studied with immunohistochemical technique and RT-PCR.Results:MCLR could enhance the positive reaction of Albert γ-GT(GGT),a preneoplasm marker.The positive reaction rate of GGT in diethylnitrosamine(DEN) + MC group was significantly higher than that in the DEN control group.The protein and RNA expression of Bcl-2 was significantly increased by MC-LR,and that the protein expression of Bax was decreased simultaneously.Conclusion:These results indicate that the MC-LR can inhabit apoptosis through the Bcl-2 and Bax genes.Therefore,we conclude that the expression change of Bcl-2 and Bax genes possibly plays an important role in the promotion of liver tumor by MC-LR.

Simulation on Calculation Accuracy of Three Methods for Live Line Measuring the Parameters of Transmission Lines with Mutual Inductance

Live line measurement methods can reduce the loss of power outages and eliminate interference. There are three live line measurement methods including integral method, differential method and algebraic method. A simulation model of?two coupled parallel transmission lines spanning on the same towers is built in PSCAD and the calculation errors of these three methods are compared with different sampling frequencies by using of Matlab. The effect of harmonic on calculation is also involved. The simulation results indicate that harmonic has the least effect on the algebraic method which provides stable result and small error.

Research on the Three-phase Photovoltaic Grid-connected Control Strategy

This paper mainly studies scheduling type photovoltaic generation system, and establishes a three-phase photovoltaic grid-connected model in Matlab/Simulink, which uses the MPPT control that can make full use of the solar energy. At the same time, energy storage device is added. The inverter of the energy storage device adopts V/f control. In the running state of the islanding because of a certain power failure, it can maintain a constant voltage and frequency. The simulation shows that as the output of the photovoltaic power increases, harmonic rate decreases under the same conditions, and the energy storage device can increase the stability of photovoltaic grid and reduce harmonic contents. So it’s very necessary to add energy storage device in the photovoltaic system.

The expression of p53 and p16 in the course of microcystin-LR inducing of liver tumor

Objective: To deeply explore the molecular mechanism of MCLR in the course of MCLR promoting liver tumor. Methods: We applied the two -stage- medium-term theory to set up the animal model, and biochemistry technique to evalu- ate the model, and then, used RT-PCR technique and image analysis to study the mRNA expression of the p53 and p16 in the course of promoting tumor. Results: (1) MCLR could enhance the positive reaction ratio of γ-Glutamyltransferase(GGT). (2) MCLR could increase the mRNA expression of p53, and had not effect on the mRNA expression of p53. Conclusion: (1) MC can promote liver tumor strongly. (2) The expression change of p53 may play an important role in the course of MCLR promoting liver tumor.

New Method of Measuring the Positive-sequence Capacitance of T-connection Transmission Lines

A novel method of measuring the positive-sequence capacitance of T-connection transmission lines is proposed. The mathematical model of the new method is explained in detail. In order to obtain enough independent equations, three independent operation modes of T-connection transmission lines during the line measurement are introduced. The digital simulation results and field measurement results are shown. The simulation and measurement results have validated that the new method can meet the needs of measuring the positive-sequence capacitance of T-connection transmission lines. This method has been implemented in the newly developed measurement instrument.

Live Line Measuring the Parameters of 220 kV Transmission Lines with Mutual Inductance in Hainan Power Grid

A live line measurement method for the zero sequence parameters of transmission lines with mutual inductance is introduced. The mathematical models of the measurement method are given. Global Positioning System (GPS) is used as the synchronous signal for the measurement carried out at different substations simultaneously. The measurement system and digital simulation results are given. Finally, the live line measurement results of two 220 kV transmission lines with mutual inductance in Hainangrid are given. Results from both simulation and on-site measurement show that the live line measurement method is feasible, and its measurement accuracy can satisfactorily meet the requirements of engineering measurement.

Gold nanorods core/AgPt alloy nanodots shell： A novel potent antibacterial nanostructure

In the light of the current problems of silver nanoparticles （Ag NPs） in terms of antibacterial performance, we have designed a novel trimetallic corelshell nanostructure with AgPt alloy nanodots epitaxially grown on gold nanorods （Au@PtAg NRs） as a potential antibacterial agent. Both Escherichia coli （E. coli） and Staphylococcus aureus （S. aureus） were studied. The antibacterial activity exhibits an obvious composition-dependence. On increasing the Ag fraction in the alloy shell up to 80%, the antibacterial activity gradually increases, demonstrating a flexible way to tune this activity. At 80% Ag, tile antibacterial activity is better than that of a pure Ag shell. The improved antibacterial ability mainly results from the high exposure of silver on the shell surface due to the dot morphology. We thus demonstrate that forming alloys is an effective way to improve antibacterial activity while retaining high chemical stability for Ag-based nanomaterials. Furthermore, due to the tunable localized surface plasmonic response in the near-infrared （NIR） spectral region, additional control over antibacterial activity using light--such as photothermal killing and photo- triggered silver ion release--is expected. As a demonstration, highly enhanced antibacterial activity is shown by utilizing the NIR photothermal effect of the nanostructures. Our results indicate that such tailored nanostructures will find a role in the future fight against bacteria, including the challenge of the increasing severity of multidrug resistance.

Fabrication of chiral plasmonic oligomers using cysteine-modified gold nanorods as monomers

Generation of circular dichroism （CD） beyond the UV region is of great interest in developing chiral sensors and chiroptical devices. Herein, we demonstrate a simple and versatile method for fabrication of plasmonic oligomers with strong CD response in the visible and near IR spectral range. The oligomers were fabricated by triggering the side-by-side assembly of cysteine-modified gold nanorods. The modified nanorods themselves did not exhibit obvious plasmonic CD signals; however, the oligomers show strong CD bands around the plasmon resonance wavelength. The sign of the CD band was dictated by the chirality of the absorbed cysteine molecules. By adjusting the size of the oligomers, the concentration of chiral molecules, and/or the aspect ratio of the nanorods, the CD intensity and spectral range were readily tunable. Theoretical calculations suggested that CD of the oligomers originated from a slight twist of adjacent nanorods within the oligomer. Therefore, we propose that the adsorbed chiral molecules are able to manipulate the twist angles between the nanorods and thus modulate the CD response of the oligomers.

The role of pathological tau in synaptic dysfunction in Alzheimer’s diseases

Alzheimer's disease(AD)is a neurodegenerative disease characterized by progressive cognitive decline,accompanied by amyloid-β(Aβ)overload and hyperphosphorylated tau accumulation in the brain.Synaptic dysfunction,an important pathological hallmark in AD;is recognized as the main cause of the cognitive impairments.Accumulating evidence suggests that synaptic dysfunction could be an early pathological event in AD.Pathological tau,which is detached from axonal microtubules and mislocalized into pre-and postsynaptic neuronal compartments,is suggested to induce synaptic dysfunction in several ways,including reducing mobility and release of presynaptic vesicles,decreasing glutamatergic receptors,impairing the maturation of dendritic spines at postsynaptic terminals,disrupting mitochondrial transport and function in synapses,and promoting the phagocytosis of synapses by microglia.Here,we review the current understanding of how pathological tau mediates synaptic dysfunction and contributes to cognitive decline in AD.We propose that elucidating the mechanism by which pathological tau impairs synaptic function is essential for exploring novel therapeutic strategies for AD.

Minimizing the effect of near-distance dielectric sensitivity on retrieving average aspect ratio of gold nanorod by optical extinction spectroscopy:in the case of CTAB adsorption

The aspect ratio(AR)is one of the most intriguing parameters of gold nanorods(GNRs),which plays an important role in determining localized surface plasmon(LSPR)properties.Instead of conventional imaging techniques,the optical extinction spectroscopy(OES)method has been developed for allowing fast statistically measuring the average AR under static approximation.In this work,combining with the previous achievements in spectroscopic technique,we further analyze the effects of gold dielectric function and near distance dielectric sensitivity.The former may reflect possible dielectric loss of real Au samples from ideal single crystalline.The latter reflects the cetyltrimethylammonium bromide(CTAB)adsorption on the surface of GNR induces different LSPR shifts below and above critical micelle concentration(CMC).However,their effect on the determination of AR has not been evaluated in OES method.The average AR measurements as a function of absorbance of CTAB-GNRs and LSPR maximum below the CMC were studied.Our results indicate that after considering these factors,the mean ARs obtained from spectroscopic techniques are closer to those obtained from imaging techniques.

Ferroxidase-like activity of Au nanorod/Pt nanodot structures and implications for cellular oxidative stress

Platinum nanoparticles （NPs） are reported to mimic various anfioxidant enzymes and thus may produce a positive biological effect by reducing reactive oxygen species （ROS） levels. In this manuscript, we report Pt NPs as an enzyme mimic of ferroxidase by depositing platinum nanodots on gold nanorods （Au@Pt NDRs）. Au@Pt NDRs show pH-dependent ferroxidase-like activity and have higher activity at neutral pH values. Cytotoxicity results with human cell lines （lung adenocarcinoma A549 and normal bronchial epithelial cell line HBE） show that Au@Pt NDRs are taken up into cells via endocytosis and translocate into the endosome/lysosome. Au@Pt NDRs have good biocompatibility at NDR particle concentrations lower than 0.15 nM. However, in the presence of H202, lysosome- located NDRs exhibit peroxidase-like activity and therefore increase cytotoxicity. In the presence of FeE＋, the ferroxidase-like activity of the NDRs protects cells from oxidative stress by consuming H202. Thorough consideration should be given to this behavior when employinK Au@Pt NDRs in biological svstems.

Temperature dependent Raman and photoluminescence of vertical WS2/MoS2 monolayer heterostructures

Heterostructures from two-dimensional transition-metal dichalcogenides MX2 have emerged as a hot topic in recent years due to their various fascinating properties. Here, we investigated the temperature dependent Raman and photoluminescence （PL） spectra in vertical stacked WS2/MoS2 monolayer heterostructures. Our result shows that both E^g and Alg modes of WS2 and MoS2 vary linearly with tem- perature increasing from 300 to 642 K. The PL measurement also reveals strong temperature dependencies of the PL intensity and peak position. The activation energy of the thermal quenching of the PL emission has been found to be equal to 69.6 meV. The temperature dependence of the peak energy well follows the band- gap shrinkage of bulk semiconductor.

Temperature-modulated inversion and switching of chiroptical responses in dynamic side-by-side oligomers of gold nanorods

Herein,a new strategy is proposed for achieving dynamic chiral controls in self-assembly systems of plasmonic nanorods based on temperature-modulation.Via enlarging Au{100}side facets of Au nanorod(AuNR)building block and changing surface ligand from often-used cetyltrimethylammonium bromide(CTAB)to cetylpyridinium chloride(CPC),inversion of chiroptical signal in side-by-side(SS)oligomers is realized.Under the guide of chiral cysteine(Cys),Au{100}side facet-linked SS rods twist in the opposite direction compared with Au{110}side facet-linked counterparts.At high CPC concentration,by controlling the incubation temperature of chiral Cys,the dominant twist mode can be regulated.Finite-difference time-domain(FDTD)simulations indicate the key role of the twisting dihedral angle of the oligomers in driving chiral signal inversion.At low CPC concentration,a temperature-sensitive chiral switching is observed owing to the conformation change of the CPC ligand layer.The temperature-modulated chiral responses are based on the interactions of chiral molecules,achiral surface ligands,and exposed facets of the building block.The rich dynamic tunability of chiroptical responses of plasmonic assemblies may find applications in stimulus-responsive nanodevices.

COVID-19 vaccination intention and vaccine characteristics infuencing vaccination acceptance: a global survey of 17 countries

Background:The availability of various types of COVID-19 vaccines and diverse characteristics of the vaccines pre‑sent a dilemma in vaccination choices,which may result in individuals refusing a particular COVID-19 vaccine ofered,hence presenting a threat to immunisation coverage and reaching herd immunity.The study aimed to assess global COVID-19 vaccination intention,vaccine characteristics infuencing vaccination acceptance and desirable vaccine characteristics infuencing the choice of vaccines.Methods:An anonymous cross-sectional survey was conducted between 4 January and 5 March 2021 in 17 coun‑tries worldwide.Proportions and the corresponding 95%confdence intervals(CI)of COVID-19 vaccine acceptance and vaccine characteristics infuencing vaccination acceptance were generated and compared across countries and regions.Multivariable logistic regression analysis was used to determine the factors associated with COVID-19 vaccine hesitancy.Results:Of the 19,714 responses received,90.4%(95%CI 81.8–95.3)reported likely or extremely likely to receive COVID-19 vaccine.A high proportion of likely or extremely likely to receive the COVID-19 vaccine was reported in Australia(96.4%),China(95.3%)and Norway(95.3%),while a high proportion reported being unlikely or extremely unlikely to receive the vaccine in Japan(34.6%),the U.S.(29.4%)and Iran(27.9%).Males,those with a lower educational level and those of older age expressed a higher level of COVID-19 vaccine hesitancy.Less than two-thirds(59.7%;95%CI 58.4–61.0)reported only being willing to accept a vaccine with an efectiveness of more than 90%,and 74.5%(95%CI 73.4–75.5)said they would accept a COVID-19 vaccine with minor adverse reactions.A total of 21.0%(95%CI 20.0–22.0)reported not accepting an mRNA vaccine and 51.8%(95%CI 50.3–53.1)reported that they would only accept a COVID-19 vaccine from a specifc country‐of‐origin.Countries from the Southeast Asia region reported the highest proportion of not accepting mRNA technology.The highest proportion from Europe and the Americas would only accept a vaccine produced by certain countries.The foremost important vaccine characteristic infuencing vaccine choice is adverse reactions(40.6%;95%CI 39.3–41.9)of a vaccine and efectiveness threshold(35.1%;95%CI 33.9–36.4).Conclusions:The inter-regional and individual country disparities in COVID-19 vaccine hesitancy highlight the importance of designing an efcient plan for the delivery of interventions dynamically tailored to the local population.

Genetic variants in promoter region of TFR2 is associated with the risk of non-alcoholic fatty liver disease in a Chinese Han population:a case–control study

Background Iron overload is frequently observed in non-alcoholic fatty liver disease(NAFLD).Transferrin receptor 2(TFR2)is an important key factor in iron regulation.We aimed to investigate whether TFR2 single nucleotide polymorphisms(SNPs)contribute to susceptibility to NAFLD in a Chinese Han population.Methods Five tag SNPs(rs10247962,rs4434553,rs2075672,rs1052897,and rs3757859)in the TFR2 gene were selected and genotyped in a case–control study on participants who visited two affiliated hospitals of Fujian Medical University between June 2011 and August 2017.Propensity score matching and inverse probability of treatment weighting analyses were used to verify the risk associated with TFR2 SNPs.Results Logistic regression analyses suggested that subjects with the rs4434553 GA or GG genotype had a lower risk of NAFLD than those carrying the AA genotype(odds ratio=0.630,95%confidence interval=0.504–0.788).Moreover,the rs4434553 GA or GG genotype was negatively correlated with body mass index,hepatic steatosis index,and serum ferritin(b=-0.363,P=0.008;b=-1.040,P=0.009;b=-35.258,P=0.015,respectively),and positively associated with serum hepcidin level(b=35.308,P<0.001).Moreover,rs10247962 and rs1052897 had multiplicative interactions with age in relation to the risk of NAFLD(P for interactions,0.041 and 0.034,respectively).The cumulative effects of the rs10247962,rs1052897,and rs4434553 SNPs were positively associated with the risk of NAFLD(adjusted P_(trend)=0.012).Conclusions In this Chinese Han population,the rs4434553 polymorphism in TFR2 may be an independent influencing factor associated with the susceptibility to NAFLD.The ageing effect on the development of NAFLD may be inhibited by SNPs rs10247962 and rs1052897.

The Profound Changes Unseen in a Century: The Perspective of Overlapping Effect of Technological Revolution Cycle and Political & Economic Thought Cycle

The waves of technological revolution can lead to great differences in the economic and social structures of countries and have a destructive impact. The choice of political and economic thoughts can amplify or inhibit such differentiation and impact. Over the past 100 years, humankind has undergone three technological revolutions, and the mainstream political and economic thoughts have experienced a cycle from classical liberalism to various types of anti-liberalism and finally to neoliberalism. In the two liberal periods, the overlap of liberalism and a technological revolution caused sharp contradictions between the rich and the poor, leading to profound economic adjustment and great political and social turmoil worldwide. In the non-liberal period, however, the overlapping effects were relatively mild. Currently, the world is facing similar trends and risks as during 1914-1940. Whether humankind will repeat the same mistakes merits attention and vigilance. This study argues that it is necessary to oppose unilateralism, uphold multilateralism, and advance globalization and free trade under the concept of collaborative development and shared prosperity, as well as explore comprehensive and sustainable development. These are of great significance for human society to prevent risks, obtain advantages and avoid disadvantages, and maintain world peace and development.