Molecular Dynamics Method Research Articles

Revealing the Thermal Stability of the Li/Sulfide Solid Electrolyte Interface at Atomic Scale via Cryogenic Electron Microscopy

AbstractUnderstanding the interfacial reaction mechanism between sulfide solid‐state electrolytes (SSEs) and metallic lithium (Li) under thermal runaway is of great significance in improving the safety of all‐solid‐state Li metal batteries (ASLMBs). Herein, multiscale methods including in situ optical microscopy‐thermal infrared imaging combination technique, cryogenic electron microscopy, thermodynamic simulation, and ab initio molecular dynamics methods are utilized to investigate the thermal chemical stability of sulfide SSEs Li10GeP2S12 (LGPS) and Li6PS5Cl (LPSCl) against metallic Li under high temperatures. The results indicate that drastic thermal runaway happened between LGPS and metallic Li at 300 °C due to the continuous Li‐Germanium alloying reaction. In contrast, LPSCl maintains stability against metallic Li up to 400 °C, which is attributed to the formation of Li2S‐LiP‐Li3P‐LiCl stable interphases in the interfacial reaction between LPSCl and metallic Li. The electrical insulation interphase prevents the further reaction between LPSCl and metallic Li via kinetically decreasing the chemical potential of metallic Li to be within the electrochemical window of LPSCl. This work demonstrates the critical role of stable electrically insulated interphases between metallic Li anode and SSEs in improving the safety of ASLMBs.

Mechanism and Structural Defects of Zinc Film Deposited on a Copper Substrate: A Study via Molecular Dynamics Simulations

Epitaxial growth can be used to guide the controllable growth of one metal on the surface of another substrate by matching the interface lattice, thus improving the dendrite tendency of metal growth. The atomic arrangement of the Cu (111) crystal plane of the FCC structure is similar to that of the Zn (0002) crystal plane of the HCP structure, which is theoretically expected to promote the heterogeneous epitaxial nucleation growth of metal zinc under low strain. In this paper, the molecular dynamics method is used to simulate the atomic process of zinc film growth on the Cu (111) surface. It is found that the behavior of zinc-adsorbed atoms on the substrate surface conforms to the epitaxial growth mode. The close-packed structure grown along the (0002) direction of the layered clusters is tiled on the Cu (111) surface, forming a highly ordered low-lattice-mismatch interface. When a large area of layered zinc clusters cover the substrate, the growth mode will change from heteroepitaxial growth to homoepitaxial growth of Zn atoms on the zinc film, forming a lamellar distribution composed of FCC and HCP structure grains. Polycrystalline zinc film with a planar structure with a (0002) surface preferred a crystal plane. The increase in incident energy is helpful in improving the quality of zinc films, while the deposition rate, corresponding to the deposition temperature and electrolyte ion concentration, has no significant effect on the surface morphology and crystal structure of single metal films. In summary, the atomic arrangement of the Cu (111) surface has a strong guiding effect on the atomic ordered arrangement in the zinc film crystal, which is suitable for the epitaxial deposition of the substrate to induce the ordered growth of the Zn (0002) crystal plane.

Mechanisms of Peptide Agonist Dissociation and Deactivation of Adhesion G-Protein-Coupled Receptors.

Adhesion G protein-coupled receptors (ADGRs) belong to Class B2 of GPCRs and are involved in a wide array of important physiological processes. ADGRs contain a GPCR autoproteolysis-inducing domain that is proximal to the receptor N-terminus and undergoes autoproteolysis during the biosynthesis to generate two fragments: the N-terminal fragment (NTF) and the C-terminal fragment (CTF). Dissociation of NTF reveals a tethered agonist to activate the CTF of ADGRs for G protein signaling. Synthetic peptides that mimic the tethered agonist can also activate ADGRs. However, mechanisms of peptide agonist dissociation and the deactivation of ADGRs remain poorly understood. In this study, we have performed all-atom enhanced sampling simulations using a novel protein-protein interaction Gaussian-accelerated molecular dynamics (PPI-GaMD) method on the ADGRG2-IP15 and ADGRG1-P7 complexes. The PPI-GaMD simulations captured the dissociation of the IP15 and P7 peptide agonists from their target receptors. We were able to identify important low-energy conformations of ADGRG2 and ADGRG1 in the active, intermediate, and inactive states, as well as different states of the peptide agonists IP15 and P7 during dissociation. Therefore, our PPI-GaMD simulations have revealed dynamic mechanisms of peptide agonist dissociation and deactivation of ADGRG1 and ADGRG2, which will facilitate the rational design of peptide regulators of the two receptors and other ADGRs.

Multi-phase uniformly distributed γ/γ′ phase interfacial friction mechanism of nickel-based single crystal alloys

Abstract The molecular dynamics method was employed to simulate the friction process at the multiphase uniformly distributed γ/γ′ phase interface of a nickel-based single crystal alloy. The results show that the presence of a coherent interface significantly affects friction force fluctuations, abrasion mark morphology, atomic displacement, and material resilience. The coefficient of friction varies with the number of interfaces and is closely related to the depth of wear. Atomic displacements and strains are affected by the lattice interfaces, which affect the propagation of strains. As the number of interfaces increases, the elasticity of the γ′ phase increases, while the elasticity of the γ phase decreases. The number of interfaces also affects the dislocation density and the dislocations due to mismatch. Adequate control of the coherent interfaces is therefore essential to optimize the friction and wear characteristics.

Modeling the Carbothermal Chlorination Mechanism of Titanium Dioxide in Molten Salt Using a Deep Neural Network Potential

The molten salt chlorination method is one of the two main methods for producing titanium tetrachloride, an important intermediate product in the titanium industry. To effectively improve chlorination efficiency and reduce unnecessary waste salt generation, it is necessary to understand the mechanism of the molten salt chlorination reaction, and consequently this paper conducted studies on the carbon chlorination reaction mechanism in molten salts by combining ab initio molecular dynamics (AIMD) and deep potential molecular dynamics (DeePMD) methods. The use of DeePMD allowed for simulations on a larger spatial and longer time scale, overcoming the limitations of AIMD in fully observing complex reaction processes. The results comprehensively revealed the mechanism of titanium dioxide transforming into titanium tetrachloride. In addition, the presence form and conversion pathways of chlorine in the system were elucidated, and it was observed that chloride ions derived from NaCl can chlorinate titanium dioxide to yield titanium tetrachloride, which was validated through experimental studies. Self-diffusion coefficients of chloride ions in pure NaCl which were acquired by DeePMD showed good agreement with the experimental data.

Molecular dynamics study on the edge effect of single crystal Ni with two indenters nanoindentation

The edge effect and the formation and evolution of dislocations in nanoindentation were studied using molecular dynamics methods. A series of molecular dynamics models of two indenter nanoindentation was constructed, and diamond indenters were used for indentation simulation. This paper analyzes the effects of two indenters distance and indentation depth on the edge side extrusion, surface collapse, indentation force, internal defects, and stress of single crystal Ni workpieces. The results show that the number of particles extruded from the side does not increase linearly with the indentation distance increasing, the magnitude of indentation force changes with the increase of indentation depth and is influenced by the distance between the indenters, and the internal defects of single crystal nickel workpieces change with the change of indentation distance and increase with the increase of indentation depth. This work has a positive impact on understanding the nanoindentation processing of single crystal Ni and can help to understand the mechanism of internal dislocation formation in workpieces under multiple indenters indentation.

A high-performance aptasensing interface based on pseudo-AuNBs@Ti3C2Tx MXene nanocomposite for non-invasive measurement of carbamazepine in human biofluids.

For the first time, a novel aptasensing interface based on smart integration of pseudo-gold nanobons (AuNBs) and Ti3C2Tx MXene isintroduced for high selective detection of carbamazepine (CBZ). The large specific surface area achieved from the proposed nanocomposite increases the targeted immobilization of the Apt sequence on the surface via AuNBs as the linkage. It embeds a high-performance grafting platform for trapping CBZ with high sensitivity and accuracy in human biofluids and pharmaceutical formulations. The molecular dynamic (MD) simulation method that exhibits how the Apt binds to CBZ in a conformation-switching assay format from a molecular view is a valid certification for the interaction of CBZ on the developed aptasensing interface. The aptasensor measured CBZ from 1 fM to 100 nM with a superior detection limit (LOD) value of 330 aM compared withother reported CBZ sensors. Due to using biocompatible and non-toxic compounds, consuming low energy and chemicals the greenness of the proposed strategy has been certified by the international scoring system.

Effect of composition, temperature, and grain size on mechanical behavior and deformation mechanism of lightweight magnesium alloy.

To address the severe fuel crisis and environmental pollution, the use of lightweight metal materials, such as AZ alloy, represents an optimal solution. This study investigates the mechanical behavior and deformation mechanism of AZ alloys under uniaxial compressive using molecular dynamics (MD) simulations. The influence of various compositions, grain sizes (GSs), and temperatures on the compressive stress, the ultimate compressive strength (UCS), compressive yield stress (CYS), Young's modulus (E), shear strain, phase transformation, dislocation distribution, and total deformation length is thoroughly examined. The results show that although AZ91 has the highest Al content, it exhibits the lowest UCS, CYS, and fraction atoms with shear strain larger than 0.2 (FSS0.2) compared to AZ31 and AZ61. At the same time, the total dislocation length of AZ31 is the largest. The effect of GS and temperature on the mechanical response and deformation mechanism of AZ31 alloy indicates that a GS of 7.6nm is the critical value to determine the mechanical properties and deformation intensity of AZ31 alloy. Moreover, the E, UCS, and CYS values decrease gradually as temperature increases. The compressive stress, E, UCS, CYS, and FSS0.2 of single crystalline AZ31 are higher than those of polycrystalline AZ31 with all GSs. The MD simulation results show that the sample experiences the formation of stacking faults at both single crystalline and polycrystalline AZ31 while forming the shear band at the single crystalline, leading to strong oscillations in compressive stress. In contrast, polycrystalline AZ31, across all GSs, exhibits high shear strain zones, causing oscillations in compressive stress. The ATOMSK program is used to create the polycrystalline AZ structures. The MD method is employed to investigate the influence of various compositions, GSs, and temperatures on the mechanical properties and deformation mechanism of AZ alloys. All the simulations are performed by LAMMPS software. The visualization tool (OVITO) is used to inspect, analyze, and illustrate the simulation results. The EAM potential is applied to the interactions between Al-Zn, Al-Mg, and Zn-Mg.

Molecular Dynamics Simulation of Low-Cycle Fatigue Behavior of Single/Polycrystalline Iron

The fatigue plastic mechanism and dislocation characteristics of engineering materials are the key to studying fatigue damage. In this study, the molecular dynamics (MD) method was employed to investigate the microstructural characteristics and fatigue mechanical properties of both single-crystalline and polycrystalline iron under varying strain amplitudes associated with cyclic hardening, cyclic softening, and cyclic saturation. The occurrence, accumulation, and formation process of the local plastic fatigue damage of monocrystalline/polycrystalline iron under fatigue load are discussed. The local plastic initiation and accumulation of single-crystal iron occur at the intersection of slip planes, which is the dislocation source. The 1/2<111> dislocation plays an important role in the fatigue plastic accumulation of single-crystal iron. Polycrystalline iron undergoes grain rotation and coalescence during cyclic loading. The grain size responsible for plastic deformation gradually increases. The initiation and accumulation of local plasticity occurs at the grain boundary, which eventually leads to fatigue damage at the grain boundary.

Molecular Dynamics Study of Fretting Wear Characteristics of Silicon Nitride Bearings

AbstractTo study fretting wear characteristics of silicon nitride bearing. Atomic model of surface fretting wear of silicon nitride bearing is constructed by molecular dynamics method and deep learning self‐fitting potential function. First principles are used to match silicon nitride crystal parameters; Dynamic analysis of fretting wear process of nanoscale silicon nitride bearing is realized. Experiment shows that friction force in the Z direction is a maximum of 3.5 nN. The output potential energy 2.31 × 107 eV is 1.63 times that of the y‐axis, which is main factor causing the fretting wear. The force perpendicular to the direction of roller and the collar of silicon nitride bearings should be avoided in the process of using or transporting the bearings. Silicon nitride bearing fretting wear process is non‐transient elastic stress‐strain, along the rolling plane extension, in the roller rolling direction to form a sharp angle shape high strain linear region. Bearing Z direction damage degree increased; Silicon nitride bearing surface layer has 22.47% of the N─Si bond fracture. The study of the fretting wear characteristics of silicon nitride ceramic bearings has a reference value for reducing the surface friction of silicon nitride bearings and improving the life of silicon nitride bearings.

Analysis of intramolecular modes of liquid water in two-dimensional spectroscopy: A classical hierarchical equations of motion approach.

Two-dimensional (2D) vibrational spectroscopy is a powerful means of investigating the structure and dynamics of complex molecules in condensed phases. However, even in theory, analysis of 2D spectra resulting from complex inter- and intra-molecular motions using only molecular dynamics methods is not easy. This is because molecular motions comprise complex multiple modes and peaks broaden and overlap owing to various relaxation processes and inhomogeneous broadening. On the basis of an anharmonic multimode Brownian oscillator model with nonlinear system-bath coupling, we have developed an approach that simulates 2D spectra, taking into account arbitrary modes of intermolecular and intramolecular vibrations simultaneously. Although only two-mode quantum calculations are feasible with this model, owing to high computational costs, here we restrict ourselves to the classical case and perform three-mode calculations. We demonstrate the applicability of our method by calculating 2D correlation infrared spectra of water for symmetric stretching, antisymmetric stretching, and bending modes. The quantum effects of these results are deduced by comparing 2D quantum spectra previously obtained for two intramolecular modes with those obtained using our classical approach under the same physical conditions. The results show that the 2D spectra calculated by separating the stretching modes into symmetric and asymmetric modes provide better descriptions of peak profiles, such as the splitting of cross-peaks.

Comparative study of the structure effect on the inhibition efficiency of three hydroxybenzylidene isonicotinohydrazide derivatives for corrosion carbon steel in a 1 M HCl solution: experimental and theoretical studies

ABSTRACT The inhibition effects of three newly synthesised hydroxybenzylidene isonicotinohydrazide derivatives, namely, (E)-N′-(2-hydroxybenzylidene) isonicotinohydrazide (ISO 2OH)), (E)-N′-(4-hydroxybenzylidene) isonicotinohydrazide (ISO 4OH)) and (E)-N′-(2,4-dihydroxybenzylidene) isonicotinohydrazide (ISO 2.4OH)) for carbon steel (CS) corrosion in 1 M HCl medium were studied. For this study, potentiodynamic polarisation (PDP), electrochemical impedance spectroscopy (EIS), surface scanning electron microscopy (SEM) analysis coupled with energy dispersive spectroscopy (EDX) analysis and computational density functional theory (DFT) and molecular dynamic (MD) simulations methods were carried out. It is found that the inhibition efficiency increases with increasing inhibitors concentrations, where the best value is about 95% at 10−3 M ISO 2.4OH. The PDP studies indicated that hydroxybenzylidene isonicotinohydrazide derivatives react as mixed-type inhibitors. However, it found that the adsorption of these inhibitor molecules on the CS obeys the Langmuir isotherm. SEM/EDX analysis of the CS specimens demonstrated that the hydroxybenzylidene isonicotinohydrazide derivatives were adsorbed and formed a protective layer on the CS area, where the UV-vis analysis revealed the formation of inhibitor-metallic complexes in the electrolyte. Finally, theoretical calculations using DFT and MDS methods have revealed good correlations between multiple chemical descriptors and the inhibition properties of the studied hydroxybenzylidene isonicotinohydrazide derivatives molecules, as well as their interaction modes with the CS surface.

Mitochondrial oxidative stress related LncRNA predict cervical cancer prognosis and immunotherapy response: Molecular structure and protein interaction of ribosomal protein L34.

The purpose of this study was to investigate the predictive value of mitochondrial oxidative stress-related LncRNA in cancer prognosis and immunotherapy response, and to further analyze the molecular structure of ribosomal protein L34 and its interaction mechanism with the protein. We screened lncrnas associated with mitochondrial oxidative stress, evaluated their expression patterns in different cancer types, and analyzed the three-dimensional structure of ribosomal protein L34 and its interaction network with other proteins. In this study, public databases were used to screen out lncrnas associated with mitochondrial oxidative stress. Bioinformatic analysis, including gene expression profile analysis, survival analysis and functional enrichment analysis, was used to evaluate the expression patterns of these lncrnas in different cancer types and their relationship with prognosis. The interacting proteins of ribosomal protein L34 were identified by proteomic techniques. The three-dimensional structure of ribosomal protein L34 and its binding mode with interacting proteins were studied by molecular docking and dynamic simulation methods. The results showed that the screened lncrnas showed significant expression differences in multiple cancer types and were closely related to the survival rate of patients. The three-dimensional structure of ribosomal protein L34 reveals key amino acid residues and binding sites for its interactions with specific proteins. Functional enrichment analysis showed that these lncrnas may affect the development of cancer through regulating oxidative stress response, cell cycle and apoptosis. The interaction network of ribosomal protein L34 reveals its central role in protein synthesis and cellular stress response.

Study on the diffusion model of two dimensional T type planar network

In this paper, we proposed a memory diffusion model of molecules on T-type planar network. This model regards the diffusion of molecules in zeolite as a jump from one adsorption site to another adjacent adsorption site. The probability of the jump is a composite probability, which includes both the probability provided by the transition state theory and the information from which direction the target molecule comes. This method gives an expression for the influence of the memory effect on the anisotropy of molecular diffusion under different conditions, revealing that the diffusion coefficients along the two crystal axes on the zeolite are related. Taking AWO zeolite as an example, the diffusion anisotropy of five simple molecules, CF4, Xe, CH4, N2, and Ar, in AWO zeolite was studied by molecular dynamics method. The main factors affecting the diffusion in zeolite were proposed, and the importance of memory effect in the molecular diffusion inside zeolite was verified.

Noncatalytic Reduction of Nitrogen Oxide and Soot Inhibition during Cocombustion with Biotar: The Molecular Dynamics Modeling Approach.

Cocombustion with biomass tar is a potential method for NO reduction during fossil fuel combustion. In this work, the molecular dynamic method based on the reactive force field was used to study the NO reduction by phenol, which is a typical tar model compound. Results indicate that phenol undergoes significant decomposition at 3000 K, resulting in the formation of small molecular fragments accompanied by the generation of large molecular, network-structured soot particles. At higher temperatures (3500 K), the morphology of the soot produced from phenol decomposition undergoes a certain degree of change. It evolves from a two-dimensional network structure to a three-dimensional particulate structure. Soot particles are significant products of the thermal decomposition process of phenol. NO acts as an oxidant during the phenol decomposition process, significantly inhibiting the formation of soot particles during this process. Phenol also promotes the reduction of NO. The corresponding NO reduction ratios of NO are 52%, 76%, and 89% for 1500, 2000, and 2500 K respectively. CO, H2O, and N2 were the three most important reaction products during phenol-NO interaction. HNO is an important intermediate during the reduction of NO by phenol. The combination of the H radical and NO is the main route for HNO. It can be seen that HNO is quickly produced at the initial stage. The calculated activated energies for NO reduction and phenol oxidation are 30.47 and 50.85 kJ/mol, respectively.

Glycyrrhetinic acid prohibiting fusion peptides from fusing with cell membrane

The inhibition of the fusion peptide (FP) of the spike protein of coronaviruses, which mediates interactions with the host cell membrane, plays a critical role in the membrane fusion process. In this study, we investigated the interactions between the FP and cell membranes and evaluated the effect of three drug molecules — neferine (Nef), glycyrrhetinic acid (GA), quercetin (Qct) on the membrane fusion process by combining molecular dynamic (MD) simulations and experimental methods. Our findings revealed that glycyrrhetinic acid exhibited strong binding ability towards the FP (residues 815‐828), with particularly interactions observed with key residues L821, L822, F823, and L828. Furthermore, we performed FITC fluorescence staining experiments on cells and assessed the inhibitory effects of glycyrrhetinic acid on FP. The results showed a significant reduction in fluorescence intensity in the FP‐FITC experiment group treated with glycyrrhetinic acid, indicating that glycyrrhetinic acid interferes with the binding ability of FP and disrupts its localization on the cell membrane. Overall, this research will contribute to a deeper understanding of the inhibition mechanism of FP’s membrane fusion process, which widely exists in the intrusion process between viruses and cells.

Thermal Transport through CTAB- and MTAB-Functionalized Gold Interfaces Using Molecular Dynamics Simulations.

Thermal transport coefficients, notably the interfacial thermal conductance, were determined in planar and spherical gold interfaces functionalized with CTAB (cetyltrimethylammonium bromide) or MTAB (16-mercapto-hexadecyl-trimethylammonium bromide) using reverse nonequilibrium molecular dynamics (RNEMD) methods. The systems of interest included (111), (110), and (100) planar facets as well as nanospheres (r = 10 Å). The effect of metal polarizability was investigated through the implementation of the density-readjusted embedded atom model (DR-EAM), a polarizable metal potential. We find that conductance is higher in MTAB-capped interfaces, due in large part to the metal-to-ligand coupling provided by the Au-S bond. Alternatively, CTAB does not couple strongly with either the metal or the solvent, and it is largely a barrier to heat transfer, resulting in a much lower interfacial thermal conductance. Through analysis of physical contact between the ligand and the solvent, we find that there is significantly more overlap in the MTAB systems than the CTAB systems, mirroring the trends we observed in the conductance.

Molecular Dynamics Simulation on the Mechanism of Shale Oil Displacement by Carbon Dioxide in Inorganic Nanopores

Shale oil reservoirs feature a considerable number of nanopores and complex minerals, and the impact of nano-pore confinement and pore types frequently poses challenges to the efficient development of shale oil. For shale oil reservoirs, CO2 flooding can effectively lower crude oil viscosity, enhance reservoir physical properties, and thereby increase recovery. In this paper, the CO2 displacement process in the nanoscale pores of shale oil was simulated through the molecular dynamic simulation method. The performance disparity of quartz and calcite slit nanopores was discussed, and the influences of nanoscale pore types and displacement rates on CO2 displacement behavior were further analyzed. The results demonstrate that the CO2 displacement processes of different inorganic pores vary. In contrast, the displacement efficiency of light oil components is higher and the transportation distance is longer. Intermolecular interaction has a remarkable effect on the displacement behavior of CO2 in nanopores. On the other hand, it is discovered that a lower displacement rate is conducive to the miscible process of alkane and CO2 and the overall displacement process of CO2. The displacement efficiency drops significantly with the increase in displacement velocity. Nevertheless, once the displacement speed is extremely high, a strong driving force can facilitate the forward movement of alkane, and the displacement efficiency will recover slightly.

Transition state theoretical modelling of molecular diffusion within the narrow pores of brewsterite zeolite.

Based on the transition state theory, a molecular diffusion model in the narrow channels of Brewsterite zeolite was established. In this model, the molecular interaction at the potential barrier was simplified to only consider the repulsive potential, so that the analytical relationship between the diffusion coefficient and the temperature and the Lennard-Jones interaction parameter was derived. We used the molecular dynamics method to simulate the diffusion of four molecules, CF4, CH4, Ar, and Ne, in Brewsterite zeolite and evaluated the rationality of the model. The results show that the three molecules CF4, CH4, and Ar meet the predictions of the model, while the Ne molecule does not. At the same time, by analyzing the trend of the diffusion coefficient with the load, we further explain the reason for this difference. In short, this study reveals the diffusion mechanism of molecules in the narrow pores of Brewsterite zeolite. This provides new ideas for optimizing the performance of zeolite materials and applying them to catalysis and separation processes. The simulations were carried out with Refson's MOLDY code in the NVT ensemble. The short-range Lennard-Jones forces were calculated with the link cell method. A Nose-Hoover thermostat was used to realize the thermal equilibrium state of the samples. In the simulation, the time steps were 1fs and the total simulation time was 51ns. The initial temperature was set to 300K.

Dynamical properties of hydrogen fluid at high pressures.

The properties of the hydrogen fluid at high pressures are still of interest to the scientific community. The experimentally unreachable dynamical properties could provide new insights into this field. In 2020 [Cheng et al., Nature 585, 217-220 (2020)], the machine-learned approach allows the calculation of the self-diffusion coefficient in the warm dense hydrogen with higher precision. After that, the work [van de Bund et al., Phys. Rev. Lett. 126(22), 225701 (2021)] reports the abinitio treatment of isotopic effects on diffusion in H2/D2 and a significant increase in its value in the region of the phase transition. Both works indicate the anomalous growth of diffusion, but the reasons for this phenomenon are unclear. In the present work, we reveal the plasma-like behavior of the diffusion growth. We apply the classical molecular dynamics method using a machine learning potential developed on the abinitio modeling for the prediction of diffusion and shear viscosity coefficients. We consider dependencies of the vibrational spectrum, molecule lifetime, diffusion, and shear viscosity coefficients on density along the isotherms in the temperature range from 600 to 1100K.