Funnel Effect Research Articles

Modeling nanovoid-enhanced water permeance of thin film composite membranes

Nanovoids in polyamide layers shape the roughness structures of thin film composite (TFC) reverse osmosis (RO) and nanofiltration (NF) membranes and have a critical influence on their water permeance. Although there have been numerous experimental works reporting enhanced water permeance by incorporating nanovoids, a systematic modeling for assessing the underlying mechanisms is still lacking. In this work, we perform numerical simulations to investigate water transport behaviors in a polyamide layer with or without a nanovoid. An analytical model, which quantifies the competition among substrate-induced unfavorable funnel effect and nanovoid-induced favorable multi-effects (i.e., surface area effect and gutter effect), is also developed and agrees well with simulation results. The model results suggest that even a tiny nanovoid of a few nanometers in size could provide an excellent self-gutter effect to minimize water transport distance. The available water permeance can be further improved by the increased effective surface area. Our modeling results reveal that the nanovoid-containing membrane can potentially offer 1–2 orders of magnitude enhancement in membrane permeance. The enhancement is greater for larger nanovoids with higher aspect ratios and for less porous substrates. Furthermore, the presence of nanovoids greatly improves the flux distribution uniformity over the membrane surface, which could potentially alleviate membrane fouling. The theoretical framework established in this work provides essential guidance for the future development of TFC membranes.

Oxidative stress as a shared mechanisms for different prenatal stressors: long-term effects on adolescent male and female mouse offspring

IntroductionStressful experiences in utero can produce physiological changes which become embedded biological traces affecting fetal brain development and ultimately leading to increased vulnerability for psychiatric disorders.ObjectivesWe hypothesized that stressors as diverse as maternal obesity and maternal psychophysical stress might disrupt fetal programming resulting in long-lasting effects on offspring brain development by acting through shared oxidative stress (OS)-mediated mechanisms.MethodsWe compared a mouse model (C57Bl/6N) of maternal high-fat diet (HFD) consumption (13 weeks, until delivery) to prenatal restraint stress (PNS) repeatedly administered during the last week of pregnancy. To counteract the negative effects of both stressors, the antioxidant N-acetyl-cysteine (NAC, 1 g/kg) was administered to female breeders for 8 weeks until delivery. Emotionality was assessed in adolescent male and female offspring through the elevated-plus-maze (EPM). Moreover, hippocampal gene expression levels of Brain-Derived-Neurotrophic-Factor (Bdnf ), Nuclear factor erythroid 2–related factor 2 (Nrf-2) and Kelch-like ECH-associated protein 1 (Keap-1) were measured, by qPCR, as markers of brain plasticity and antioxidant capacity.ResultsPrenatal exposure to both HFD and PNS enhanced behavioral disinhibition, increasing time spent in the open arms of the EPM and decreasing the frequency of risk-assessment behaviors, especially in female offspring. Moreover, both prenatal stressors led to decreased Bdnf (in females) and Nrf-2 levels, and disrupted Keap-1 levels. Prenatal NAC was able to counteract these effects on the brain.ConclusionsOur data support the hypothesis of a “funnel effect” model explaining how different prenatal stressors result in long-term negative effects on the adolescent offspring, increasing risk assessment behaviors and affecting brain plasticity and antioxidant defenses. The beneficial preventive effects of NAC suggest that OS may be a common mechanism, playing a pivotal role in fetal programming of mental disorders. ERANET-NEURON-JTC-2018-Mental Disorders-“EMBED” and Bando Ricerca Indipendente ISS 2021-2023; MOMINFLAM. Unique signatures underlying placental-fetal brain crosstalk in maternal obesity to F Cirulli.Disclosure of InterestNone Declared

Does Surface Roughness Necessarily Increase the Fouling Propensity of Polyamide Reverse Osmosis Membranes by Humic Acid?

Surface roughness has crucial influence on the fouling propensity of thin film composite (TFC) polyamide reverse osmosis (RO) membranes. A common wisdom is that rougher membranes tend to experience more severe fouling. In this study, we compared the fouling behaviors of a smooth polyamide membrane (RO-s) and a nanovoid-containing rough polyamide membrane (RO-r). Contrary to the traditional belief, we observed more severe fouling for RO-s, which can be ascribed to its uneven flux distribution caused by the "funnel effect". Additional tracer filtration tests using gold nanoparticles revealed a more patchlike particle deposition pattern, confirming the adverse impact of "funnel effect" on membrane water transport. In contrast, the experimentally observed lower fouling propensity of the nanovoid-containing rough membrane can be explained by: (1) the weakened "funnel effect" thanks to the presence of nanovoids, which can regulate the water transport pathway through the membrane and (2) the decreased average localized flux over the membrane surface due to the increased effective filtration area for the nanovoid-induced roughness features. The current study provides fundamental insights into the critical role of surface roughness in membrane fouling, which may have important implications for the future development of high-performance antifouling membranes.

Oil spill response technology for ice-covered waters in the Arctic

A technology for removing oil spills from under the ice, based on the use of the vortex funnel effect, is proposed. A comparative analysis of methods oil pollution removal from under the ice cover is carried out. Models of the processes of separation of the “ice-oil-water” system occurring in the vortex funnel are presented, as well as, based on the experiment, photo illustrations of the stages of formation of the vortex funnel and removal of oil from under-ice. The schemes of deployment and operation of mobile equipment for removing oil spills from under the ice are proposed. It is shown that the proposed approach to liquidation of emergency oil spills in the Arctic can be used to create means and technologies of liquidation of more large-scale disasters of this kind.

Recoil and charged particle energy spectra from the natSi(n,x) reaction and the Si semiconductor detector response to the 14 MeV neutrons

The energy spectra of light and heavy charged particles generated by the 14 MeV neutrons in silicon nuclei and in the Si semiconductor detector (SSD) were analysed. The existing measurements were used to validate the corresponding energy differential cross sections from major evaluations ENDF/B-VIII.0 and JEFF-3.3. The required data were extracted by the various codes: NJOY21, SPKA and MCNP6. It was shown that both evaluations underestimate the high energy part of the 28Si(n,x)p- and α-particle spectra by ≤50%, whereas at smaller emission energies no experimental data even exist. The calculation of the atom displacement damage in SSD reveals that the secondary protons produce additionally ≈15% of damage, whereas the contribution from secondary alphas is impossible to estimate since the Si(α,x) recoil data are not available.The single experiment, carried out by K. Yageta and co-workers in 1988, reported the energy spectra in the Si semiconductor down to the rather low energy of ≈0.3 MeV, at which the production of reaction recoils dominates over the light ions. The Monte Carlo simulation of this experiment was performed by MCNP6. The generation and transport of all relevant ions were taken in account. The energy depositions from protons or alphas were summed with their associated recoils after correction for non-ionization losses. The neutron reactions in the dead layer of the SSD were shown to increase the counts in active layer by (1–20)% depending on sort of ions. The impact of the field funneling effect was studied. Consideration of all these underlying processes has eventually allowed a reasonable reproduction of this experiment.

Concentrated subradiant modes in a one-dimensional atomic array coupled with chiral waveguides

Non-Hermitian systems have recently attracted broad interest and exhibited intriguing physical phenomena, in which the non-Hermitian skin effect is one of the most remarkable quantum phenomena desiring detailed investigations and has been widely studied in various fermionic and bosonic systems. Here we propose a non-Hermitian atom-waveguide system composed of a tilted one-dimensional atomic array coupled with two identical waveguides with opposite chiralities. Such system creates an effective lattice model including nonreciprocal long-range hoppings through the chiral-waveguide photon-mediated interactions. We find the excitation of the collective atomic states concentrates in the middle interface, pointing towards the non-Hermitian skin effect associated with subradiant modes, while, on the contrary, superradiant modes exhibit extended features. Simulation results present subradiant funneling effect, with robustness against small atomic position disorders. Our work underpins the fundamental comprehension towards the non-Hermitian skin effect in open quantum systems and also provide prospective paths to study non-Hermitian systems in the area of quantum optics.

Effects of the coupling between slope morphology and bottom currents on flow erosion and sedimentation at the Dongsha Continental Margin, South China Sea

Abstract The Dongsha Continental Margin (DCM) projects seaward and is situated in the path of bottom currents coming through the only deep-water exchange passage, the Luzon Strait between the South China Sea (SCS) and the western Pacific Ocean. This provides an opportunity to observe the different interaction between the two wings of the convex margin and the bottom currents, and help understand the corresponding implications for provenance, debris transportation, and sedimentation in such an environment. The convexity of the DCM causes its eastern flank to shrink against upcoming bottom currents and internal solitary waves (ISWs), producing a funneling effect and forming strong erosion grooves or strips, remnant seamounts, and large seafloor coarse debris dunes. The concavity of the western flank induces the expansion of bottom currents that flow around the plateau, resulting in a depositional zone with weak erosion that mainly interacts with bottom currents and gravity flow. The strong erosion on the DCM caused by the bottom current forms the primary provenance of the deep-water environment, while the nepheloid layer that entraps the fine debris of the gravity flow that derives from Taiwan and that is transported by the bottom current is the secondary provenance. The different coupling patterns between the bottom currents and the two flanks determine the different modes of debris transportation and deposition. Debris eroded by the currents is mainly transported by the gravity flow on the eastern flank while sweeping of the outer shelf and upper slope by eddy currents, progradation of the gravity flow, and reworking by the bottom current mainly occur on the western flank. Two types of morphological breaks, namely, continental slope break and bottom-current slope break, have developed on the DCM. They control the evolution of the flow regime of the multi-layer bottom currents and the gravity flow of the DCM as well as the effects of erosion and deposition. These two types of slope breaks are coupled and form an area in front of Dongsha Island with the highest deposition rate in the SCS.

Efficient Light‐Emitting Diodes via Hydrogen Bonding Induced Phase Modulation in Quasi‐2D Perovskites

AbstractQuasi‐2D perovskites have drawn considerable attention in light‐emitting diodes due to their tunable energy landscape, efficient luminescence, and structural diversity. However, the excessive formation of low‐n (n ≤ 2) phases leads to lower carrier injection efficiency arising from the large injection barrier. Meanwhile, inefficient energy transfer caused by undesirable phases distribution results in multipeak emission. In this study, polar anti‐solvent is used that can interact with spacer cations via strong hydrogen bonding, tailoring phases distribution to address the issue. The ethyl acetate treatment induces preferential growth of large‐n phases and enhances energy transfer due to the strong hydrogen bonding energy ≈ −17 kcal mol−1. Leveraging these insights, efficient sky‐blue and green perovskite light‐emitting diodes are developed with improved external quantum efficiency ranging from 4.21% to 8.77%. The anti‐solvent treatment can open up a new avenue to regulate the phase distribution for an efficient energy funnel effect.

MGM-4-FL: Combining federated learning and model gossiping in WSNs

Application of Federated learning (FL) as it is, in Wireless Sensor Networks (WSNs) in impractical. In fact, it requires the transmission of a large number of model parameters. Also, it implies the consumption of a massive amount of energy and communication resources at nodes located closer to the network elements that aggregate the models calculated by the federated learners. This is a well known problem in WSN called funneling effect. Solutions have been recently proposed that decentralize FL operations further by exploiting multihop communications. Nevertheless, the proposed approaches do not focus on the networking operations needed to support such decentralization in an efficient manner. Objective of this paper is to fill this gap by proposing an integrated networking/learning scheme, named Model Gossiping Method for FL, that supports distributed FL efficiently in wireless sensor networks.

Forecasting Technique Bridges Gap Between Material Balance and Reservoir Simulation

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203941, “Bridging the Gap Between Material Balance and Reservoir Simulation for History Matching and Probabilistic Forecasting Using Machine Learning,” by Nigel H. Goodwin, Essence Analytics. The paper has not been peer reviewed. Currently, building and maintaining a reservoir simulation model is the bottleneck for reservoir decision support. In this paper, the authors describe an approach for creating a digital twin that is informed by the data itself based on established physics modeling and uses a fully probabilistic Bayesian approach. Statistical Time-Series Modeling and Physics Models Differences Between Statistical Models and Physics Models. The statistical model includes an error term for each timestep. In practice, this means that the predicted fit to historic data is very good and the error terms are small, but forecasting can have a major funneling effect. Many methods exist for forecasting of statistical models, but the increasing uncertainty of prediction over time, and the large magnitude of uncertainty, is a common feature. The error term implies a future random walk behavior. When forecasting, multiple single-step integrations are being performed in which each step has its own error. Where known values of exogenous variables exist in the future, prediction uncertainty can be greatly ameliorated. In contrast, the differential algebraic equations (DAE) for a physical model have no error term for each timestep. Each time the model is run with the same parameter values, the same results are obtained. The error in reservoir simulation lies in measurement error and model error. Errors exist in individual historical measurements (or maybe systemic errors), and the model and its parameters are known to be wrong. For forecasting, a range of models and model parameter values are used—ideally, based around a robust Monte Carlo approach. An ensemble of forecasts can then be generated that represent uncertainty.

5G Hybrid System Design and Energy Efficient Resource Allocation Deployment

5G communication provide a promising platform for new, innovative and diverse enhanced mobile broadband (eMBB) and massive device connectivity applications, such as streaming media, machine vision and Internet of Things (IoT), real-time and dynamic data processing, intensive computation. However, 5G multimedia devices deployment relies on the coverage of base stations, which is inefficient and costly in wide-area coverage and physical penetration. In this paper, a 5G and wide-area Ad Hoc network fusion architecture is proposed to flexibly provide scalable 5G and extensible low-power devices interconnection liberated from geographical restriction, which consists of a low-power wide-area network and an edge processing gateway. Moreover, the intelligent edge gateway near a specific base station can support real-time ultra-high-definition video streams access and achieve traffic optimization by compressing, intelligent identification and preprocessing of the video streams to alleviate traffic congestion. The coverage capacity efficiency of wide-area Ad Hoc networks is restricted by the "funnel effect" in multihop cascading, and adaptive resource allocation strategies will present a promising approach to realize energy-efficient deployment. A non-convex optimization problem is formulated to maximize the energy-efficient deployment of Ad Hoc network. Then, a coordination and optimization strategy of internal resource allocation in deployed multihop nodes based on Lagrange relaxation algorithm was presented to solve the optimization problem. The actual system deployment and real measurement proved that the system function is running normally and stably. The experimental simulation test results show that the proposed 5G wide-area Ad Hoc network can effectively make up for the adaptive streaming needs of 5G coverage blind spots. Compared with static resource allocation, the proposed resource allocation and deployment scheme reduces energy consumption by 42.31%.

Microporous Cyclodextrin Film with Funnel‐type Channel Polymerized on Electrospun Cellulose Acetate Membrane as Separators for Strong Trapping Polysulfides and Boosting Charging in Lithium–Sulfur Batteries

The “shuttle effect” of polysulfides hampers the commercialization of lithium–sulfur (Li‐S) batteries. Here, a thin molecular sieve film was decorated on the surface of an electrospun cellulose acetate (CA) membrane derived from recycled cigarette filters, where the truncated cone structure β‐cyclodextrin (β‐CD) was selected as the building block to physically block and chemically trap polysulfides while simultaneously dramatically speeding up ion transport. Furthermore, on the β‐CD free side of the separator facing the cathode, graphite carbon (C) was sputtered as an upper current collector, which barely increases the thickness. These benefits result in an initial discharge performance of 1378.24 mAh g−1 and long‐term cycling stability of 863.78 mAh g−1 after 1000 cycles at 0.2 C for the battery with the β‐CD/CA/C separator, which is more than three times that of the PP separator after 500 cycles. Surprisingly, the funnel‐type channel of β‐CD generates a differential ionic fluid pressure on both sides, speeding up ion transport by up to 69%, and a 65.3% faster charging rate of 9484 mA g−1 was achieved. The “funnel effect” of a separator is regarded as a novel and high‐efficiency solution for fast charging of Li‐S and other lithium secondary batteries.

Probing Nanoscale Exciton Funneling at Wrinkles of Twisted Bilayer MoS2 Using Tip-Enhanced Photoluminescence Microscopy.

In twisted bilayer (t2L) two-dimensional (2D) transition metal dichalcogenides, local strain at wrinkles strongly modulates the local exciton density and PL energy resulting in an exciton funneling effect. Probing such exciton behaviors especially at nanometer length scales is beyond the limit of conventional analytical tools due to the limited spatial resolution and low sensitivity. To address this challenge, herein we applied high-resolution tip-enhanced photoluminescence (TEPL) microscopy to investigate exciton funneling at a wrinkle in a t2L MoS2 sample with a small twist angle of 0.5°. Owing to a spatial resolution of <10 nm, excitonic behavior at nanoscale sized wrinkles could be visualized using TEPL imaging. Detailed investigation of nanoscale exciton funneling at the wrinkles revealed a deformation potential of -54 meV/%. The obtained results provide novel insights into the inhomogeneities of excitonic behaviors at nanoscale and would be helpful in facilitating the rational design of 2D material-based twistronic devices.

Experiments on snowdrifts around two adjacent cube models based on a combined snow-wind facility

This study conducted experiments on the wind-induced snow drifting around two adjacent cube models, using artificial snow in an open air snow-wind combined experimental facility constructed at the Harbin Institute of Technology (HIT). In particular, 20 experiments were conducted on two adjacent cubes with three different wind directions, three different wind speeds, and four different spacings. They were compared with contrast experiments with a single cube under the same inflow condition. The cube models were two wooden cubes having dimensions of 0.5 × 0.5 × 0.5 m. The drift process of natural snowfall was simulated by scattering snow particles. After snowfall for 25 min in each experiment, the snowdrifts were measured by surveying approximately 300 points around the cubes. Contour maps of the normalized snow depths were drawn and analyzed. The experiments show that the wind direction and speed have a certain influence on a snowdrift. Based on the wind-snow movement mechanism, the relationship between the snowdrift pattern around two cubes and the snowdrift pattern around a single cube was explored. Under the same condition, the snowdrift pattern around the multiple cubes can be deduced from the snowdrift pattern around the single cube. The snowdrift pattern around the downstream cube depends on its spatial position relative to the upstream cube. Moreover, the snowdrift between two adjacent cubes seems to be dependent on a funneling effect.

Ionic-compound based high performance perovskite light emitting diodes

Metal halide perovskite has attracted much attention due to its adjustable color, high color purity, and excellent photoelectric properties. The quality of the perovskite film is one of the key factors that affect the performance of device. Here, PEA&lt;sub&gt;2&lt;/sub&gt;Cs&lt;sub&gt;&lt;i&gt;n&lt;/i&gt;–1&lt;/sub&gt;Pb&lt;sub&gt;&lt;i&gt;n&lt;/i&gt;&lt;/sub&gt;Br&lt;sub&gt;3&lt;i&gt;n&lt;/i&gt;+1&lt;/sub&gt; thin films are prepared by directly doping the ionic compound additive tetraphenylphosphine chloride (TPPCl) into the perovskite precursor of the light-emitting layer based on additive assisted technology. High-quality perovskite films with uniform, less pinholes and smaller grains are obtained. Not only is the photoluminescence (PL) performance of PeLEDs improved but the electroluminescence (EL) performance of PeLEDs with a double electron transport layer also turns better. The maximum brightness is 25285 cd/m&lt;sup&gt;2&lt;/sup&gt;. The maximum current efficiency is 65.9 cd/A. And the maximum EQE is 17.3%. The method of adding ionic compounds to the perovskite precursor can not only improve the carrier transport behavior, but also make the formed small n crystal phases and large n crystal phase more balance, leading to the energy funnel effect to be enhanced. Further investigation by FTIR proves that the TPPCl can passivate the perovskite film, and thus greatly improving the EQE value of the PeLED. This researchpresents a simple and efficient method of developing high-performance quasi-two-dimensional green PeLEDs.

Multi-decadal changes of mangrove forest and its response to the tidal dynamics of thane creek, Mumbai

Mangroves are one of the world threatened ecosystems, which is protected and categorised under CRZ-I according to the Coastal Regulation Zone (CRZ) notification. The present study marked the decadal (1990–2017, Landsat series) change of mangroves and mapped the species distribution (2017, Sentinel-2) around Thane creek, Mumbai using SMLC with QGIS-SCP software. ADCIRC model was used to simulate the tidal flooding/ebbing towards mangroves, and the model was validated with the in-situ observation of tides and currents. From 1990 to 2017, the mangrove area increased from 79.14 km2 to 154.5 km2 and expanded towards landward and seaward regions. Between 2010 and 2017, there was a fluctuation in the mangrove area with ups and downs in their distribution caused by different climatic conditions and anthropogenic activities. The increase in built-up area was two times than mangrove area increase. The dominance of Avicennia marina species confirms the increased anthropogenic activity along the landward side. To understand the response of mangroves to the tidal dynamics, the model was simulated with two scenarios; with mangroves and without mangroves. In the absence of mangroves (without mangroves), Thane Creek demonstrated a perfect funnelling effect by increased tidal amplification with strong flood currents, resulting in severe coastal inundation and erosion. While with mangroves, tidal currents attenuated 80% of its magnitude and favoured the sediment deposition in mangrove areas, which further enhanced mangrove growth, thereby stabilising the coast. The present study has found that the mangroves in the Thane creek are in the saturation stage and reached the maximum growth towards the landward. The study envisages that the stakeholders should adopt a proper management plan for the restoration of mangroves. The highlight of the present study is the combination of satellite imagery and hydrodynamic modelling. Satellite imagery provides the estimated extent of the mangroves, and this information will be used when simulating the model, which provides maximum inundation and attenuation. The utilisation of LULC classification and ADCIRC model results would be helpful to examine the threatening built-up area due to the tidal inundation. The combination of satellite classification and hydrodynamic model findings will be decisive for management authorities towards the conservation and regeneration activities for a balanced mangrove-creek ecosystem.

Cybernetics Approach Using Agent-Based Modeling in the Process of Evacuating Educational Institutions in Case of Disasters

In the context of an emergency, evacuating people from a location in the shortest possible time is essential, as is the high degree of safety that people should expect when evacuating. Lately, in Romania there have been more and more fire events generated by different causes. This article will use agent-based modeling to simulate an emergency evacuation model in NetLogo. The model has been used to perform and analyze various scenarios. With the help of NetLogo, we managed to perform 400 simulations with the evacuation of 180 people (students, teachers, and non-teaching staff) based on which we developed several recommendations to streamline the evacuation process in order to reduce the possibility of death. The present research will help to identify the evacuation times from a school, but it will also highlight certain aspects that may occur during the evacuation. The model that was used in this research took into account the individual particularities of the people taking part in the evacuation, emphasizing the effects that form in a crowd of people when evacuating; effects such as the funnel effect, which is caused by the formation of bottlenecks around narrow areas. All these things are part of the analysis of the measurement of entropy of the exhaust system, a problem that has captured all of the specialists’ attention. Finally, solutions have been proposed to improve evacuation time in case of disasters.

Cavitation funnel effect: Bio-inspired leading-edge tubercle application on ducted marine propeller blades

Cavitation is an ever-present issue in the maritime industry as it causes damage to the propeller in the form of erosion, reducing hydrodynamic performance and increasing the underwater radiated noise (URN) level generated. Therefore, containing cavitation on marine propellers is an important area to research in order to reduce structural damage, efficiency loss and noise pollution. Recently there has been growing research in the leading-edge (LE) tubercles located on Humpback whale pectoral fins that have been attributed to give the whales superior manoeuvrability through prolonged flow attachment and have shown to improve hydrodynamic performance on marine applications.This paper assesses the sheet cavitation containment capability of the LE tubercles on a benchmark ducted propeller blade in both heavy and light cavitating conditions. The analysis is carried out over a range of operating conditions using commercial code STAR-CCM+ with the implicit unsteady Improved Delayed Detached Eddy Simulation (IDDES) method and the Schnerr-Sauer cavitation model. The investigation encompassed two tubercle designs with varying geometrical configurations of wavelength while maintaining the amplitude.In summary, it was found that LE tubercles as applied to the Kaplan propeller blade has presented a cavitation funnel effect which can successfully reduce the sheet cavitation development by a maximum of 50%, while enhancing the total thrust coefficient in all operating conditions by a maximum of 10%. Comparing at the same thrust loading coefficient, the propulsive efficiency in heavy-cavitating conditions can be improved by a maximum of 6.5%.

Research and method of air burst fracturing

At present, shale gas pressure fracturing volume development technology tends to be mature, shale gas backlog fracturing ends and enters the trial production stage. Due to the improper control of oil nozzle or its causes, the output drops sharply, or the drainage in the production process makes the funnel effect near the wellbore zone, resulting in the closure of the main fracture passage near the wellbore. However, the far-end complex sealing network structure produced by volume fracturing technology is still not fully closed, or secondary fractures occur in the absence of support for the original wellbore fractures or new complex fractures occur in the vicinity of the wellbore. The simple use of high-energy gas fracturing requires low cost, safety and simple and efficient characteristics, and the requirements for surface equipment are not too high. Existing methods mainly include well testing, sand washing by coiled tubing, gas lifting by coiled tubing, wellbore plugging removal, pumping and drainage by supplementary pressure well operator, etc. They can not fundamentally solve the need of closing or reopening new fractures in wellbore, and can not make new complex unclosed fractures near wellbore zone (without secondary fracturing). If the investment of surface equipment for secondary fracturing is similar to that of the first volume fracturing, and the investment is similar, the more complex situation will arise because of filtration and other reasons. At present, low concentration methane in air and wellbore is used to oxidize and exothermic to produce CO2 and H2O, and release energy at the same time. Temperature and pressure are the main means of energy in limited space. High energy gas formed after volume work can help to reopen the original fracture and form a new type of high energy gas fracturing method by means of air ignition and explosion, because the effect of high energy gas fracturing is not affected by stress, new cracks can be produced, and this crack can avoid overlapping with previous cracks. In particular, it can be pointed out that due to the improvement of thermal recovery of heavy oil and other means, the ground operation equipment has the commonality, and reasonable optimization of the construction plan can achieve the established purpose.

Tailoring the Energy Funneling across the Interface in InSe/MoS2 Heterostructures by Electrostatic Gating and Strain Engineering

AbstractAs a representative 2D semiconductor in the III–VI family, indium selenide (InSe) retains both high carrier mobility and direct bandgap even down to few‐layer limit. However, it exhibits relatively weak light absorption of normally incident light due to its unique optical anisotropy different from transition metal dichalcogenides, significantly impeding its optoelectronic applications. Herein, it is demonstrated that the light emission of InSe can be enhanced by a maximum of 2.5 times via energy funneling effect in MoS2/InSe type‐I heterostructures, the band alignment and charge transfer process of which are explored by optical spectroscopic technique, Kelvin probe force microscopy, and optoelectronic measurements. The energy funneling effect in MoS2/InSe heterostructure is not only significantly tuned by electrostatic gating, but also preserves high efficiency upon applying a uniaxial tensile strain up to 0.52%, making it appropriate for both rigid and flexible superior optoelectronic devices. Besides, the charge transfer at the heterointerface in MoS2/InSe changes from funneling to exciton dissociation via layer engineering of MoS2, with a maximum hole transfer rate of 9 × 108 s−1 from InSe to MoS2. This work provides approaches to tune the charge transfer across the van der Waals heterointerface, giving rise to promising applications in quantum optoelectronics.