Channel Intersections Research Articles

Flood simulation and impact analysis of Xun River under backwater condition

Abstract The intersection of river channels is easy to cause the backside of the main flow, which greatly influences the change of hydrological conditions of river channels. To study the changing characteristics of river flood under the condition of uplift, a one-dimensional hydrodynamic model was established to simulate the evolution process of river flood under the condition of seeking river uplift. Factors such as distance, height, flood speed, inundation area, inundation depth, and flood speed were selected to analyze the changing rules of the influence of river bullying. The results show that the influence degree of the river following is closely related to the size of the flood. Under the same earthquake magnitude, the backwater distance, backwater height, inundation area, inundation depth, and inundation speed of sub-river flood increase with the increase of flood magnitude, while the flood speed decreases. When the magnitude of the flood is once in 200 years, the flood elements reach the maximum, the reflux distance is 8, 368 m, the reflux height is 3.2 m, and the velocity is reduced by 43.2%. This study can provide relevant data for the flood control work in the Sun River basin and provide a reference for the scheme design of tributary interchanges.

Sedimentary Reservoir Characteristics of Fuyu Oil Formation in the Middle of Fuxin Uplift, Southern Songliao Basin

Currently, the Fuyu reservoir in the middle of the Fuxin uplift, located in the southern Songliao Basin, is in a high water cut development stage. The understanding of this reservoir is limited, and the distribution of favorable reservoirs remains unclear, necessitating detailed reservoir characterization. This study employs a combination of well and seismic technologies to accurately depict the sedimentary and reservoir characteristics of the Fuyu oil reservoir. By conducting detailed correlations of oil zones, a regional high-resolution isochronous stratigraphic framework is established. The division of sedimentary microfacies enables fine characterization of single sand bodies, identifying channel boundaries, clarifying lateral connectivity, and detailing the vertical contact relationships of sand bodies across different deposition periods. The results demonstrate that root-mean-square amplitude and total energy metrics effectively correspond to sand bodies in the study area and can be used to analyze sand body distribution. Provenance is primarily from the southwest to the northeast, with shallow deltas predominantly developed. Delta plain subfacies are found in zones 4-12, while delta front subfacies are in zones 1-3. Microfacies types mainly include the main distributary channel, distributary channel sides, crevasse splay, overbank sand, and underwater distributary channels. The main distributary channel reservoirs exhibit the best physical properties, with porosity ranging from 20-25%, while sand bodies at the sides of distributary channels reach 15-20%. Predicted favorable areas are mainly located at the intersections of distributary channels and structural highs, where drilling is likely to yield high oil flow.

Deformation mechanisms of additively manufactured Hf10Nb12Ti40V38 refractory high-entropy alloy: Dislocation channels and kink bands

To date, the reported refractory high-entropy alloys (RHEAs) with strength and ductility synergy all have up to 1 GPa strain hardening rate (SHR). Keeping the SHR of more than 1 GPa in the RHEAs can postpone the point of plastic instability, thus prolonging the uniform tensile ductility (UTD). In this paper, Hf10Nb12Ti40V38 RHEA with high strength and ductility is successfully manufactured by laser-directed energy deposition (L-DED). The yield strength of the alloy is about 1011 MPa with the tensile ductility of ∼12.6 %. Interestingly, the SHR of the alloy is very low, far below 1 GPa. The stress-strain curve of the alloy does not only show no premature dropout, but also exhibits a flat plateau-type curve. For this interesting phenomenon, the deformation mechanisms of Hf10Nb12Ti40V38 alloy are systematically investigated by investigating the deformation microstructures. The results indicate that the dislocation modes are diversifying, but the limited number of tangles generated by the intersection of dislocation channels are the main source of SHR. Various dislocation configurations such as single dislocation channel and cross-slip are stimulated sequentially, and although they have no positive effect on the SHR of the alloy, they allow alloy to accommodate plastic deformation. Combined with the kink bands as a strain softening mechanism, it improves the ductility while decreasing the SHR. Multiple dislocation channels interactions and kink bands are clearly identified as the two deformation mechanisms governing strain hardening and strain softening. The competition between two mechanisms generates the phenomenon mentioned above. This study does not only shed new insights on the unique deformation behavior of Hf10Nb12Ti40V38 RHEA but also complement the current general perception about the relationship between SHR and ductility of RHEAs.

Using Nanoscale Passports To Understand and Unlock Ion Channels as Gatekeepers of the Cell.

Natural ion channels are proteins embedded in the cell membrane that control many aspects of cell and human physiology by acting as gatekeepers, regulating the flow of ions in and out of cells. Advances in nanotechnology have influenced the methods for studying ion channels in vitro, as well as ways to unlock the delivery of therapeutics by modulating them in vivo. This review provides an overview of nanotechnology-enabled approaches for ion channel research with a focus on the synthesis and applications of synthetic ion channels. Further, the uses of nanotechnology for therapeutic applications are critically analyzed. Finally, we provide an outlook on the opportunities and challenges at the intersection of nanotechnology and ion channels. This work highlights the key role of nanoscale interactions in the operation and modulation of ion channels, which may prompt insights into nanotechnology-enabled mechanisms to study and exploit these systems in the near future.

Ultrabroadband valley transmission and corner states in valley photonic crystals with dendritic structure

In photonic crystal systems, topologically protected edge states and corner states can be achieved by breaking spatial inversion symmetry, which is expected to be applied to topologically protected lasers, optical communication and integrated photonics. However, designing ultrabroadband topological photonic crystals is still a challenge. In this work, we propose a valley photonic crystal composed of dendritic structures, which can realize valley transmission with a relative bandwidth up to 59.65%. Compared with the previously reported two-dimensional broadband photonic crystals with 32.02% bandwidth, the relative bandwidth of the proposed valley transmission is increased by almost 100%. Theoretical analysis, numerical simulation and experimental measurement all confirm flexible manipulation of electromagnetic wave propagation paths. Ultrabroadband topological waveguides with the zigzag and armchair interface are demonstrated, which can achieve experimentally 58.71% and 36.78% relative bandwidth, respectively. In addition, several topological channel intersections are designed. Finally, two types of corner states with valley switchability and selectivity are demonstrated.

Large‐scale computational screening of highly effective zeolites for trace PH3 capture from hydrogen

AbstractDeveloping highly efficient adsorbents to remove trace PH3 from circulating H2 is essential for electronic‐grade silica production. Here, the pure PH3 adsorption and PH3/H2 separation performances of 103 all‐silica zeolites under various operating conditions were simulated using grand canonical Monte Carlo simulation. Based on our well‐validated force field, the optimal ranges of zeolites and the most decisive factors for pure PH3 adsorption and separation were identified by the combination of quantitative structure–activity relationship, Pearson coefficient, and adsorption density profile. Finally, the top 17 zeolites were identified through TSA, PSA, and VSA processes, which typically feature 10‐membered rings as limiting pores. Structures with 1D channels show the best performance. Some 2D and 3D zeolites (i.e., IMF, ITH, ITR, MEL, TUN), which are characterized by interconnected straight channels with cavities at channel intersections, also exhibit high selective adsorption capacities for PH3. This work provides direction for the design of novel zeolites.

Tailoring the product distribution of CO2 hydrogenation via engineering of Al location in zeolite

Even though tremendous progress has been made on modified Fischer-Tropsch synthesis (FTS) multifunctional catalyst that composed of Fe-based component and acidic zeolite H-ZSM-5 for CO2 hydrogenation into value-added chemicals, the structure-function relationship between the acidic zeolite H-ZSM-5 and product distribution is still under debate. Herein, a series of H-ZSM-5 zeolites with different Al locations and acidic properties are fabricated by varying the synthesis raw agents and conditions. After combining with the carbon-encapsulated Fe-based catalyst for alkenes synthesis from CO2 hydrogenation, aromatics are directionally produced from the ellipsoidal H-ZSM-5 with Al species mainly located at the intersection of straight and sinusoidal channels, while the main products shift to iso-paraffins for the H-ZSM-5 with pillared nanosheet morphology owing to its Brønsted acid site-rich property. The Al location in H-ZSM-5 and the corresponding acidic property are systematically investigated, and the theoretical simulations illustrate that the Al species at the intersection channels could lower the energy barrier of key aromatization step. The Al richly located at straight/sinusoidal would boost the isomerization reaction. Our work not only clarifies the structure-function relationship of acidic zeolite H-ZSM-5 in valuable chemicals synthesis from CO2 hydrogenation but also provides a novel protocol for controlled synthesis.

Regulating framework aluminum location towards boosted light olefins generation in ex-situ catalytic pyrolysis of low-density polyethylene

Amidst the global focus on recycling and treatment of waste plastics for resource sustainability, it remains an enormous challenge to convert waste plastics into light olefin. Herein, the impact of framework Al (AlF) location in ZSM-5 catalyst, controlled by regulating Al sources, on the ex-situ catalytic pyrolysis of low-density polyethylene (LDPE) has been investigated. Based on multi-techniques, such as 27Al MAS NMR, ICP-AES, Co-UV–vis-DRS, XRD, SEM, N2 adsorption-desorption, NH3-TPD, Py-IR and FTIR. It is found that the AlF located at the channel intersections show more Al pairs, and this location offers ample space for secondary reactions, which include Diels-Alder reaction, cyclization reaction and dehydrogenation reaction, resulting in the low yield of light olefins (10.6 wt%) and the generation of light alkanes and aromatics from light olefins. In contrast, AlF located in the straight and sinusoidal channels exists mainly in the form of single Al. The substantial steric hindrance for this location facilitates the cracking reaction, mainly referring to the cracking reactions of LDPE that produce light olefins and generate enhanced yield of light olefins (52.8 wt%). These results provide new perspectives towarding boosted light olefins generation in ex-situ catalytic pyrolysis of LDPE.

Three-Stage Rapid Physical Design Algorithm for Continuous-Flow Microfluidic Biochips Considering Actual Fluid Manipulations

With the continuous development of microfluidic technology, continuous-flow microfluidic biochips (CFMBs) are being increasingly used in the Internet of Things. The automation design of CFMBs has also received widespread attention. The architecture design of CFMBs is divided into a high-level synthesis stage and a physical design stage. Among them, the problem of the physical design stage is very complex. At this stage, the chip architecture is generated based on the device library and a set of flow paths, taking into account the actual fluid manipulations, while minimizing the cost of the chip, such as the number of ports, total length of flow channels, number of flow channel intersections. As fabrication technology advances, the number of devices integrated into CFMBs is increasing. The existing physical design algorithms can no longer meet the design requirements of CFMBs in terms of time. Therefore, we propose a three-stage rapid physical design algorithm for CFMBs considering the actual fluid manipulations. The proposed algorithm includes a port-driven preprocessing stage, a force-directed quadratic placement stage, and a negotiation-based routing stage. In the port-driven preprocessing stage, a port-driven preprocessing algorithm is proposed to generate connection matrices between ports and devices to reduce the number of ports introduced. In the force-directed quadratic placement stage, we model the placement problem as an extremum problem of a quadratic cost function, which mathematically reduces the search space significantly and shortens the running time of the algorithm significantly. In the negotiation-based routing stage, a heuristic negotiation-based routing algorithm and a flow channel strategy that prioritizes the construction of parallel execution are proposed to reduce the running time of the algorithm while ensuring that the number of crossings in the routing solution is close to the optimal solution. Experimental results confirm that our proposed method is able to generate the high-quality solutions quickly. Under general scale problems, compared to the existing method based on ILP, our proposed method achieves a speedup ratio of 23,171 in terms of CPU time and optimizations in terms of number of ports and port reuse of 3.18% and 6.52%, respectively. These optimizations come at the cost of only a slight increase in the number of intersections, the flow length, and the number of flow valves. In addition, our proposed method can effectively solve large-scale problems that cannot be solved by existing method based on ILP.

Architectural Synthesis of Continuous-Flow Microfluidic Biochips with Connection Pair Optimization

Continuous-flow microfluidic biochips are a type of biochip technology based on microfluidic channels that enable various biological experiments and analyses to be performed on a tiny chip. They have the advantages of a high throughput, high sensitivity, high precision, low cost, and quick response. In the architectural synthesis of continuous-flow microfluidic biochips (CFMBs), prior work has not considered reducing component interconnection requirements, which led to an increase in the number of connection pairs. In this paper, we propose an architectural synthesis flow for continuous-flow microfluidic biochips with connection pair optimization, which includes high-level synthesis, placement, and routing. In the high-level synthesis stage, our method reduces the need for component interconnections, which reduces the number of connection pairs. Our method performs fine-grained binding, ultimately obtaining high-quality binding and scheduling results for flow paths. Based on the high-quality binding results, we propose a port placement strategy based on port correlation and subsequently use a quadratic placer to place the components. During the routing stage, we employ a conflict-aware routing algorithm to generate flow channels to reduce conflicts between liquid transportation tasks. Experimental results on multiple benchmarks demonstrate the effectiveness of our method. Compared with the existing work, the proposed algorithm obtains average reductions of 35.34% in connection pairs, 24.30% in flow channel intersections, 21.71% in total flow channel length, and 18.39% in the execution time of bioassays.

The role of Ni-containing species on methanol-toluene methylation to p-xylene over ZSM-5 zeolite

The methylation of toluene with methanol is an important process for the preparation of p-xylene (PX). The modification of Ni-containing species in HZSM-5 can improve the yield of PX. However, the active site existence form of Ni is unclear. The intrinsic reaction mechanisms for methylation of toluene with methanol over HZSM-5 with NiOH+ and Ni2+ as Lewis acid have been investigated. The results indicate that the introduction of Ni2+ decreases the activity for the methanol dissociation, whereas NiOH+ enhances the activity with a reduction in activation energy of 100.7 kJ/mol. Furthermore, the generation of three xylenes, as well as the conversion of PX to 1,2,4-Trimethylbenzene (1,2,4-TMB) have also been studied over NiOH+/HZSM-5. It is shown that PX is most easily formed with the lowest energy barrier of 84.8 kJ/mol in four products, implying the introduction of NiOH+ in HZSM-5 favors the formation of PX. In addition, molecular dynamics simulations show that toluene reacts with methanol to form xylenes mainly at the intersection of channels. PX exhibits a much higher self-diffusion coefficient than MX and OX when the temperature rises from 498 to 698 K. It can be concluded that NiOH+ is the active Ni-containing species and NiOH+/HZSM-5 is an excellent catalyst for the production of PX via the methylation of toluene with methanol.

Oxidative carbonylation of methane into acetic acid: Effect of metal (Zn, Cu, La, and Mg) doping on Rh/ZSM-5 activity

It was shown that the nature and method of the second element-modifier (Zn, Si, La, and Mg) introduction have a significant effect on the acidic properties of the zeolite catalysts and the active component (Rh) localization, which leads to a change in their catalytic properties in the oxidative methane carbonylation into acetic acid. The most active second components were Cu and Zn, introduced by impregnation (acetic acid yield was 919 and 819 μmol·gcat−1, respectively). Using temperature-programmed desorption of NH3, Fourier-transform infrared spectroscopy of pyridine adsorption and X-ray photoelectron spectroscopy it was found that an improvement of catalyst efficiency was associated with an increased acidity and a greater content of Brѳnsted acid sites together with an increase in the proportion of Rh atoms inside microporous channels and/or channel intersection voids, that are active in the acetic acid formation.

Structure and Properties of TiNi Shape Memory Alloy after Quasi-Continuous Equal-Channel Angular Pressing in Various Aged States

The effect of quasi-continuous (QC) equal-channel angular pressing (ECAP) in various pre-aged states on the structure formation and mechanical and functional properties of a hyper-equiatomic titanium nickelide (TiNi) shape memory alloy is studied. QC ECAP with a channel intersection angle of 110° is carried out at a temperature of 450 °C after aging for 1 and 5 h for three passes. To investigate the obtained structure and properties, the following research methods are applied: transmission electron microscopy, XRD analysis, calorimetric study, tension and hardness tests, and a special technique for the determination of functional properties. QC ECAP allows for the considerable refinement of structural elements and results in obtaining a mixed fine-grade structure, with structural elements of average sizes of 92 nm after pre-aging for 1 h and 115 nm after pre-aging for 5 h. Pre-aging for 5 h before QC ECAP, in combination with QC ECAP and post-deformation aging at 430 °C for 1 h, provides the best combination of mechanical and functional properties: a dislocation yield stress of 1410 MPa, ultimate tensile strength of 1562 MPa, and total recoverable strain of 11.6%. These values are comparable with the best results obtained for titanium nickelide and expand opportunities for the application of smart shape memory devices.

Mixture Adsorption in Nanoporous Zeolite and at Its External Surface: In-Pore and Surface Selectivity.

Using toluene, ethylene, and water as gas compounds with different representative molecular interactions, we perform atom-scale simulations for their mixtures to investigate the selectivity of the core nanoporosity and external surface in a prototypical zeolite. As expected, the overall behavior suggests that increasing the pressure of a given component promotes the desorption of the coadsorbing species. However, for water-toluene mixtures, we identify that the pseudohydrogen bonding between water and toluene leads to beneficial coadsorption as toluene adsorption in the low-pressure range promotes water adsorption. Moreover, when the zeolite is completely filled with water, toluene adsorption does not occur due to steric repulsion, and ethylene shows oversolubility as the amount of ethylene per water molecule is significantly larger than in bulk water. The underlying oversolubility mechanism is found to be due to localized ethylene adsorption in the density minima arising from the layering of water in nanoconfinement. Despite these specific effects, the relatively weak coadsorption effects in the zeolite nanoporosity, which are found to be reasonably captured using the ideal adsorbed solution theory, arise from the fact that adsorption of these gases having different molecular sizes occurs in distinct pore regions (channel type, channel intersection). Finally, in contrast to confinement in the nanoporosity, mixture adsorption at the external surface does not show coadsorption effects as it mostly follows the Henry regime. These results show that selectivity is mostly governed by the confinement effects as the external surface leads to a selectivity loss.

Effect of structure parameters on internal mass transfer and performance of PEMFC with spider-web flow field using multi-physical simulation

Optimizing the flow field structure is an important means to enhance gas transport and improve the proton exchange membrane fuel cell (PEMFC) performance. Based on the structural features of the spider-web, a three-dimensional multiphase flow model of the PEMFC with a spider-web biomimetic flow field (SWFF) was established firstly, and the influence of inlet and outlet positions on the performance of the PEMFC was investigated, then the cathode side catalytic layer (CL) oxygen utilization as an evaluation index based on the cluster model was proposed, which is used to investigate the effect of inlet and outlet positions on internal mass transfer and performance of PEMFC. Finally, the influence of different structural parameters on the performance of PEMFC with SWFF was investigated based on the orthogonal experimental design method. The results show that a reasonable arrangement of inlet and outlet positions can effectively increase the peak current density by 2.31% and reduce the pressure drop by 96.07% compared to a serpentine flow field. The placement of baffles at the intersection of the main channel and divergent channels can significantly improve the PEMFC performance. The results of the research provide a new evaluation index and a theoretical basis for the optimal design of flow field structures.

Аналитическая модель равноканального углового прессования титановой губки

Introduction. The use of equal-channel angular pressing (ECAP) of metal powder makes it possible to obtain practically non-porous blanks with high hardness, with a high level of accumulated deformation and with the formation of an ultra-fine-grained structure. A relevant issue for the study of the semi-continuous ECAP process remains a reliable assessment of the energy-power parameters of the process and the prediction of the porosity of compressed materials. This, in turn, is due to the need to develop sufficiently accurate, reliable and simple mathematical models for practical application. The purpose of the work is to develop an analytical model of the process of equal-channel angular pressing of porous material. Powdered screening of spongy titanium of the TG-100 brand was selected as a model of the material for the study. The object of the study is the process of semi-continuous equal-channel angular pressing of axisymmetric porous briquette of titanium sponge in the channel of the mold. It is assumed that the ECAP uses a punch to create back pressure. For the solution, a process scheme, a statically permissible load scheme on a layer of intense deformation and a kinematically permissible flow scheme of a plastically compressible medium in a layer are determined. A system of equations is constructed in accordance with the accepted schemes. The equation power balance is applied. The analytical equation is solved by the method of successive approximations. Finite element simulation of the porous titanium ECAP process was carried out at the angles of intersection of the mold channels at 45°, 50°, 55° and 60°. Results and Discussion. The porosity of the blank is determined at different stages of the ECAP process. A diagram of the change in pressure on the punch using the analytical solution and finite element simulation is obtained. It is revealed that the results of the analytical solution are consistent with the data of the finite element simulation. The highest stress level occurs in the process of equal-channel angular pressing at α = 45°, however, the distribution of relative density over the cross section is most uniform. The maximum value of the pressure on the working punch decreases with an increase in the angle α. Rational technological parameters of pressing porous blanks should provide the maximum permissible pressure on the deforming tool. From this condition, in each specific ECAP process, it is possible to determine the optimal angle value from the analytical solution.

Boosting Methanol-Mediated CO2 Hydrogenation into Aromatics by Synergistically Tailoring Oxygen Vacancy and Acid Site Properties of Multifunctional Catalyst.

Even though the direct hydrogenation of CO2 into aromatics has been realized via a methanol-mediated pathway and multifunctional catalyst, few works have been focused on the simultaneously rational design of each component in multifunctional catalyst to improve the performance. Also, the structure-function relationship between aromatics synthesis performance and the different catalytic components (reducible metal oxide and acidic zeolite) has been rarely investigated. Herein, we increase the oxygen vacancy (Ov ) density in reducible Cr2 O3 by sequential carbonization and oxidation (SCO) treatments of Cr-based metal-organic frameworks. Thanks to the enriched Ov , Cr2 O3 -based catalyst affords high methanol selectivity of 98.1 % (without CO) at a CO2 conversion of 16.8 % under high reaction temperature (350 °C). Furthermore, after combining with the acidic zeolite H-ZSM-5, the multifunctional catalyst realizes the direct conversion of CO2 into aromatics with conversion and selectivity as high as 25.4 % and 80.1 % (without CO), respectively. The property of acid site in H-ZSM-5, especially the Al species that located at the intersection of straight and sinusoidal channels, plays a vital role in enhancing the aromatics selectivity, which can be precisely controlled by varying the hydrothermal synthesis conditions. Our work provides a synergistic strategy to boost the aromatics synthesis performance from CO2 hydrogenation.

A multi-fusion integrated end-to-end deep kernel CNN based channel estimation for hybrid range UM-MIMO 6G communication systems

In today’s world, Terahertz Communication (THzCom) is envisioned as a highly promising technology to characterize 6G wireless communication within the range from 0.1 to 10 THz. This will configure emerging wireless applications due to the demand for their unique potential to support terabit-per-second transmission and effectively support ultra-high quality of service requirements. Aiming at massive dual beamforming problem in THzCom, the Ultra-Massive-Multiple Input and Multiple Output (UM-MIMO) with less array based hybrid channel modelling is adopted as the promising solutions. Further, in the case of an ultra-massive number of antennas, the beamforming matrix element is quite high-dimensional. This enlarged dimension of channel contributes to the high complexity of Channel Estimation (CE). To focus on these challenges, we presented a Hybrid Short and Long range Channel Model (HSLCM) based Multi-Fusion based Deep Kernel Convolutional Neural Network (MF-DKCNN) for THz UM-MIMO CE method. HSLCM channel modelling is used to determine the channel parameters of THz propagation paths, such as path loss, azimuth and elevation angles, distance, and the steering vector of the lens array. The MF integrated with the DKCNN model is used to estimate the noise-free received signal from accurate channel parameters and handles high-dimensional matrices with low complexity. MF employs the Channel Intersection Fusion Rule (CI-FR) to combine the received signal and channel matrix for a consistent fusion estimate of the known channel parameters from the system model. The DKCNN network structure has fifteen layers in which the MF estimates the noise-free channel matrices to be processed as training labels. Then, the kernel evaluation is used between layers to solve high dimensions and feature complexity. The proposed model is analysed in an outdoor THz channel scenario, which was simulated on the MATLAB (R2018A) platform. Hence, the evaluation results demonstrate that the proposed method outperforms high CE results with low complexity than other methods in terms of training data and Normalized Mean Square Error (NMSE).

Structure and properties of TiNi shape memory alloy after low-temperature ECAP in shells

The effect of low-temperature equal-channel angular pressing (ECAP) in shells on the structure formation and mechanical and functional properties of a near-equiatomic titanium nickelide (TiNi) shape memory alloy is studied. ECAP with channel intersection angles of 120° and 110° is carried out at temperatures in the 20 °С to 330 °С range after 1 pass. The optimum material for shells is pure iron, which is not destroyed after ECAP down to room temperature. The optimum deformation temperature of ECAP in a shell is determined to be 200 °С. Deformation at low temperatures leads to the premature destruction of TiNi samples. ECAP of the TiNi core in a shell at 200 °С after 1 pass leads to the formation of an elongated, banded martensite structure with a bandwidth of approximately 100 nm. The best combination of mechanical and functional properties is found after ECAP of a TiNi sample with a diameter of 12 mm in core-shell mode at 200 °С followed by the addition of post-deformation annealing at 400 °С for 1 h.

Basic thermodynamic characteristics and isotherm of ammonia adsorption in NaZSM-5 and LiZSM-5 zeolites

This paper presents the results of isotherm and basic (ΔH, ΔF, and ΔS) thermodynamic characteristics of ammonia adsorption in Na zeolites2,87 ZSM-5 and Li3,37 ZSM-5; also the adsorption isotherm is described by the bulk micro-pore filling theory (BFM) equations. The correlation between adsorption-energy characteristics is found, and the molecular mechanism of ammonia adsorption in Na2,87ZSM-5 and Li3,37ZSM-5 zeolites in the whole filling region is revealed. The ammonia adsorbed in NaZSM-5 and LiZSM-5 zeolites is located in the first coordination sphere with Na+ and Li+ cations, forming octa- and hexaammonia complexes. From the adsorption thermokinetics, it was determined that Li+ cations are located in the screened positions of the ZSM-5 zeolite crystal lattice. The adsorption of ammonia molecule results in Li+ cations migration from the zeolite lattice into junctions formed by the intersection of straight and zigzag channels and the formation of ion/molecular complexes of various multiplicity in them. It was determined that the average molar entropy of ammonia adsorption on NaZSM-5 and LiZSM-5 zeolites indicates that the mobility of ammonia molecules in the zeolite is below the liquid phase and close to the mobility of the solid phase, indicating a strong limitation of mobility of ammonia adsorbed on the cations.