Key issues in water sealing performance of underground oil storage caverns: Advances and perspectives

Water sealing performance is important for underground water-sealed oil storage(UWSOS).The key issues concerning water sealing performance mainly include the permeability of fractured rock mass(FRM),water-sealed safety(WSS),water curtain performance,and prediction and control of water inflow.This paper reviews the progress of above four key issues on water sealing performances.First,the permeability of an FRM is the basis of water sealing performance,and several commonly used permeability test methods and spatial variation characteristics of permeability are outlined.Second,the current water sealing criteria are compared,and the evaluation methods of WSS are summarized.Third,the design parameters and efficiency evaluation of water curtain systems(WCSs)are introduced.The water inflow of oil storage caverns(OSCs)can reflect the water sealing effect,and the prediction methods and control measures of water inflow are also summarized.Finally,the advantages and disadvantages of the current research are discussed,and the potential research directions are pointed out,such as optimization of water sealing criteria and FRM model,quantitative evaluation of WCS efficiency,accurate prediction of water inflow,and improvement of grouting technology.

High-performance liquid-phase catalytic purification of phosphine in tail gas using Pd(Ⅱ)/Cu(Ⅱ)composite

Pd/Cu liquid-phase composite was utilized as the catalyst in this study to remove PH_(3) at low temperatures.The anti-heterotoxicity of catalysts in the PH_(3) catalytic oxidation purification process was carefully explored and pioneered.The catalytic performance,thermodynamics,kinetics,and catalytic oxidation mechanism of Pd/Cu liquid-phase catalyst catalytic oxidation of PH_(3) were thoroughly investigated.The results showed that Pd/Cu has a superior catalytic effect on the removal of PH_(3) in the gas mixture under low temperature.With CO as the carrier gas,the removal efficiency of PH_(3) could be maintained at 100%for nearly 450 min,indicating that the Pd/Cu liquid phase catalyst has good resistance to heterotoxicity.According to the thermodynamic,kinetic,and related characterization results of the PH_(3) purification process,the kinetic region of the gas–liquid reaction of PH_(3) absorption by Pd/Cu solution was an interfacial reaction.Pd was the primary catalyst and Cu was the secondary catalyst,and the adsorption of PH_(3)was a primary reaction.PH_(3) was spontaneously oxidized to H_(3)PO_(4) in the Pd/Cu catalytic system during the removal process.Pd was regenerated by O_(2) and Cu,increasing the activity and stability of the Pd/Cu catalyst in the sustain and efficient purification of PH_(3) in tail gas.

Etching-courtesy NH_(4)^(+) pre-intercalation enables highly-efficient Li^(+) storage of MXenes via the renaissance of interlayer redox

Inspired by a well-known architecture notion that load-bearing walls enable maintaining a highly-stable multiple-floored building,superior advantages are afforded via fabricating the NH_(4)+ions pre-intercalated Mo_(2)CT_(x) MXene(Mo_(2)CT_(x)-N)in a mixed solution of NH_(4)F and HCl via a simple one-step hydrothermal method.As a result of the synergistic effects of pillared structure,immobilizing-F groups and unlocking Mo-based redox,the Mo_(2)CT_(x)-N remarkably delivered a reversible capacity of 384.6 mAh ^(g-1) at 200 mA g^(-1) after 100 cycles.Our work lays a foundation for fully packaging its optimal performance via carding and architecting the chemistry of the MXene layers and between them.

Evolution of edge turbulent transport induced by L-mode detachment in the HL-2A tokamak

This paper presents the characteristics of L-mode detachment,together with the behavior of edge turbulent transport and plasma confinement on the HL-2A tokamak.Partially detached and pronounced detached states have been achieved in L-mode plasma.Stored energy was maintained before and after detachment.Edge turbulence and its transport have increased obviously in the partially detached state.In the pronounced detached state,redistribution of the density and temperature profiles due to detachment leads to low amplitude of electron temperature and pressure,as well as very weak edge turbulence and transport.Despite strong plasma radiation in the pronounced detached state,reduced edge turbulent transport contributes to maintaining stored energy in detached L-mode plasma in HL-2A.Different detachment states play an important role in the redistribution of density and temperature profiles,which requires further study.

Advances of nanoparticles in transmucosal drug delivery

Transmucosal drug administration represents a potential strategy for enhancing treatment efficacy and reducing side effects by avoiding the first-pass effect into the systemic circulation and delivering therapeutics directly to the target disease site.However,many challenges still remain in its clinical application,including low drug availability and limited retention time in the mucosa.The burgeoning advancement of nanotechnologies offers great potential to overcome the above limitations,leveraging their distinct advantages of high drug-loading capacity and strong permeability.In this review,the latest developments of nanoparticles(NPs)in transmucosal drug delivery as well as their clinical applications are discussed.

Enhancing the capabilities of biosafety laboratories through the established accreditation system:Development of the biosafety laboratory accreditation system in China

Accreditation is now widely used to attest for laboratory competence.Although accreditation was originally used to assess products in testing laboratories and still plays an increasingly important role in international trade,it has been expanded to include laboratories in many social fields,including forensic science,medicine,and animal quarantine reference.The accreditation process provides basic requirements for achieving global recognition for laboratory reports.This paper introduces the concept of accreditation and discusses the origins and development of the accreditation system in Chinese biosafety laboratories.This study also reveals the important role of this system in national biosafety management through an examination of the 14-year development of the Chinese biosafety laboratory accreditation system.

La ions-enhanced NH_(3)-SCR performance over Cu-SSZ-13 catalysts

Lanthanum(La)ions are generally recognized to cause a decline of the catalytic performance for Cu-SSZ-13 zeolite in the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).Herein,we demonstrate that the NH_(3)-SCR performance and hydrothermal stability of Cu-La-SSZ-13 zeolites can be enhanced with the incorporation of a small amount of La ions.The incorporation of La ions into SSZ-13 favors more Z_(2)Cu^(2+)ions at six-membered rings(6MRs),which results in higher hydrothermal stability of Cu-La-SSZ-13 than that of Cu-SSZ-13.The NO conversion of Cu-La-SSZ-13 achieves 5%–10%higher than that of Cu-SSZ-13 at the temperature range of 400–550℃ after hydrothermal ageing.While introducing excess amount of La ions in SSZ-13 may cause the formation of inactive CuO_(x),leading to the decrease of catalytic activity and hydrothermal stability.Notably,the low-temperature activity of Cu-SSZ-13 with a low Cu content(≤2 wt.%)can be boosted by the introduction of La ions,which is largely due to the improved redox ability of Cu active sites modified by La ions.Density functional theory(DFT)calculations indicate that La ions prefer to locate at eight-membered rings(8MRs)and thus promoting the formation of more Z_(2)Cu^(2+)ions.Meanwhile,the existence of La ions in SSZ-13 inhibits the dealumination process and the transformation from Z_(2)Cu^(2+)to CuO_(x),resulting in its enhanced hydrothermal stability.The present work sheds a new insight into the regulation of secondary metal cations for promoting high NH_(3)-SCR performance over Cu-SSZ-13 zeolite catalysts.

不饱和聚酯树脂水解回收制备可循环利用的水溶性薄膜

废弃塑料的回收利用引起了全球的广泛关注,其中热固性塑料由于树脂稳定致密的三维网络结构,回收难度极大.现有的化学回收方法存在降解条件苛刻,反应选择性低,以及未能兼顾再生产品的可回收性等不足.基于此,本文报道了一种简单温和的不饱和聚酯树脂(UPR)降解及产物高值循环利用的方法.采用二乙烯三胺和氢氧化钠二元碱体系,通过选择性地完全断裂UPR结构中的酯键,得到苯乙烯–马来酸共聚物钠盐(SMA-Na).并进一步以之为原料制备得到具有较好耐溶剂性和力学性能的水溶性薄膜.利用SMA对pH的敏感性,通过简单的水溶解–酸化提取–再成膜过程即可实现薄膜的循环再生.该工作为热固性树脂的温和高效回收与循环利用提供了新的思路.

Absolute Structure Determination of Chiral Organic Nanocrystals Using Zone-Axis Electron Diffraction

Enantiomorphic identification of chiral molecules is essential in organic chemistry and the pharmaceutical industry,as two enantiomorphic structures can show distinctively different properties.Here,we illustrate the absolute structural determination of organic nanocrystals using zone-axis electron diffraction by taking advantage of electron multiple scattering.Two enantiomorphs are distinguished by comparing the reflection intensities of Friedel pairs in the zone-axis electron diffraction pattern,after confirming the absolute indices of reflections by locating relative positions of diffraction spots from two patterns that deviate from a certain angle.We demonstrate the protocol with successful applications in two chiral drug nanocrystals.

Optimization of optical signal-to-distortion ratio in a channel-interleaved photonic ADC via a coherent multi-frequency RF driver

A microwave-chip-based coherent multi-frequency RF driver is developed for a channel-interleaved photonic analog-todigital converter(PADC) system, which comprises a multi-class optical demultiplexer and supports a sampling speed of 40 GSa/s. The generated signals from the RF driver are adjustable in both amplitude and phase. We analyze the relationship between the characteristics of the generated RF driver signals and the demultiplexing performance in theory based on the optical signal-to-distortion ratio(OSDR). It is the most effective parameter to evaluate the performance of the demultiplexer in a PADC system without an electronic analog-to-digital converter. By precisely adjusting the amplitude and phase of signals, the OSDR is optimized. The results verify the compatibility between the RF driver and the PADC system.

CMM-based method for assessing the volume change of retrieved polyethylene cups in MoP total hip replacements

Wear occurring at the bearing surface and the consequent generation of wear debris has been identified as the primary cause of aseptic loosening in metal-on-polyethylene(MoP)hip joint replacements.The accurate estimation of volume change in polyethylene cups due to creep and wear is,therefore,an important step for identifying the cause of failure and improving the longevity of MoP prosthesis.The purposes of this study were to present and apply a co-ordinate measuring machine(CMM)-based method for assessing the volume change of retrieved components due to wear and creep by using a combination of CMM data and a bespoke computer programme.The method was firstly validated against the standard gravimetric technique,and then applied to four retrieved polyethylene cups for wear assessment and analysis.The results show that the volume changes calculated using the present method match well with those assessed through the gravimetric technique.The CMM-based method presented in the study is capable of effectively and reliably determining the volume change and characterising the wear patch of retrieved components from MoP hip joint replacements.