Minimum Energy State Research Articles

Valuable Biodiesel Catalyst from Solvay Wastewater

Biodiesel is considered a renewable, green fuel as it is derived from renewable living resources like animal fats or vegetable oils. This research is utilized to investigate the possibility of using Solvay wastewater as a source of biodiesel catalyst, which is CaO. CaCl2 from Solvay wastewater reacts with CO2 to produce CaCO3. CaCO3 is then heated to produce pure CaO. Waste cooking oil, wastewater, and CO2, which are considered dangerous materials to the environment, are used to produce valuable products. This research has environmental and economic benefit benefits of using waste materials as a replacement for raw materials. The selected experimental parameters for the CaCO3 production step are stirring rate (500–1300) rpm, CO2 gas flow rate (900–2000) mL/min, amount of ammonia (15–35) mL, and glycerol volume (0–25) mL. The selected experimental parameters for the biodiesel production step are reaction time (2–6) h, methanol to oil ratio (9–15), catalyst loading (1–5) %, and reaction temperature (50–70) °C. The impact of reaction parameters on reaction responses was assessed using the response surface methodology technique. A formula that represents the reaction response as a function of all the independent factors has been created. The optimization of the process is done in two steps: the first one is for the CaCO3 process while the second one is biodiesel production optimization. The first optimization was done to get the CaCO3 with minimum particle size and yield. The second optimization was done to get the maximum amount of biodiesel using minimum energy and low reaction conditions. Process optimization resulted in another economic benefit for this research. The resulted biodiesel yield equals 95.8% biodiesel yield at 2 h reaction time, 15:1 molar ratio of methanol to oil, 56 °C reaction temperature, and 1% catalyst loading.

Marlics: A finite difference liquid crystal simulation package

In this paper we present Marlics (Maringá Liquid Crystal Simulator), a software written in C++ to obtain either the system dynamics, by using the Runge-Kutta method, or the minimum energy states with the Fast Inertial Relaxation Engine (FIRE) for both achiral and chiral nematic liquid crystals. The system solved by Marlics consists in the dynamical evolution for the Q-tensor in the Landau-de Gennes formalism for different geometries, including confined slab cells and spherical, liquid crystal droplets. Furthermore, the code accepts custom geometries, so the user may provide a particular geometry of interest to run simulations. The program takes as input a descriptive file giving the simulations parameters and initial conditions, generating a series of different snapshots distributed in time according to the users' needs. Several initial conditions are provided to help the user starting simulations direct to different goals. The code is organized in class modules, which can be modified by the user base to attend their further needs. Program summaryProgram Title: MarLicSCPC Library link to program files:https://doi.org/10.17632/xb728xftgv.1Code Ocean capsule:https://codeocean.com/capsule/5639788Licensing provisions: GNU General Public License v3.0Programming language: C++Supplementary material: In the S.I the user will find an input file example and the complete list of setup parameters.External routines: The code needs the GSL (Gnu scientific library), an implementation of the CBLas library and an implementation of the OpenMp library (optional).Nature of problem: Marlics was developed to simulate liquid crystal devices via solution of the Landau-de Gennes Equation.Solution method: The system of equations is solved using finite differences in both time and space. The time integration is performed using an explicit integrator with or without variable time-step. We also provide a relaxation engine (FIRE), which is specialized in finding equilibrium states of the same system of dynamical equations.Additional comments including restrictions and unusual features: The code is parallelized using OpenMp, consequently it can only be run in parallel with shared memory processors.The source code comes with the input files and scripts used to generate the results and figures showed in this work.

Optimal Biomechanical Performance in Upper-Limb Gestures Depends on Velocity and Carried Load.

Simple SummaryIn the last few years, the physical health and mental health of workers in an industrial context while interacting with collaborative robots have become of primary interest in the research field. The characterization of the mental and psychophysical health of workers and subjects can be investigated with biomechanical analysis. In this work, a biomechanical model was used to perform simulations of the biomechanics of reaching against gravity movements as a paradigmatic motion primitive underlying several functional tasks. Motion tracking data were acquired with motion capture, and, in a simulation environment, multiple movement speeds and carried loads were changed in order to analyze the effects on upper-limb kinematics and dynamics. An optimal range of velocities for human motion was found in which the expended energy was lower. The deviation from energy optimum for the upper limb was evaluated when testing nonoptimal movement conditions. These results can be useful in a human–robot collaboration scenario to tune setup parameters to preserve the physical and mental health of the workers, to assess biomechanics, and to define fatigue and effort indices.In the last few years, there has been increased interest in the preservation of physical and mental health of workers that cooperate with robots in industrial contexts, such as in the framework of the European H2020 Mindbot Project. Since biomechanical analysis contributes to the characterization of the subject interacting with a robotic setup and platform, we tested different speed and loading conditions in a simulated environment to determine upper-limb optimal performance. The simulations were performed starting from laboratory data of people executing upper-limb frontal reaching movements, by scaling the motion law and imposing various carried loads at the hand. The simulated velocity ranged from 20% to 200% of the original natural speed, with step increments of 10%, while the hand loads were 0, 0.5, 1, and 2 kg, simulating carried objects. A 3D inverse kinematic and dynamic model was used to compute upper-limb kinematics and dynamics, including shoulder flexion, shoulder abduction, and elbow flexion. An optimal range of velocities was found in which the expended energy was lower. Interestingly, the optimal speed corresponding to lower exerted torque and energy decreased when the load applied increased. Lastly, we introduced a preliminary movement inefficiency index to evaluate the deviation of the power and expended energy for the shoulder flexion degree of freedom when not coinciding with the minimum energy condition. These results can be useful in human–robot collaboration to design minimum-fatigue collaborative tasks, tune setup parameters and robot behavior, and support physical and mental health for workers.

X-Ray Emission from the Jets and Lobes of the Spiderweb

Abstract Deep Chandra and Very Large Array imaging reveals a clear correlation between X-ray and radio emission on scales ∼100 kpc in the Spiderweb radio galaxy at z = 2.16. The X-ray emission associated with the extended radio source is likely dominated by inverse Compton upscattering of cosmic microwave background photons by the radio-emitting relativistic electrons. For regions dominated by high surface brightness emission, such as hot spots and jet knots, the implied magnetic fields are ∼50–70 μG. The nonthermal pressure in these brighter regions is then ∼9 × 10−10 dynes cm−2, or three times larger than the nonthermal pressure derived assuming minimum energy conditions, and an order of magnitude larger than the thermal pressure in the ambient cluster medium. Assuming ram pressure confinement implies an average advance speed for the radio source of ∼2400 km s−1 and a source age of ∼3 × 107 yr. Considering the lower surface brightness, diffuse radio-emitting regions, we identify an evacuated cavity in the Lyα emission coincident with the tail of the eastern radio lobe. Making reasonable assumptions for the radio spectrum, we find that the relativistic electrons and fields in the lobe are plausibly in pressure equilibrium with the thermal gas and close to a minimum energy configuration. The radio morphology suggests that the Spiderweb is a high-z example of the rare class of hybrid morphology radio sources (or HyMoRS), which we attribute to interaction with the asymmetric gaseous environment indicated by the Lyα emission.

Annealing synchronizes the 70S ribosome into a minimum-energy conformation

Researchers commonly anneal metals, alloys, and semiconductors to repair defects and improve microstructures via recrystallization. Theoretical studies indicate that simulated annealing on biological macromolecules helps predict the final structures with minimum free energy. Experimental validation of this homogenizing effect and further exploration of its applications are fascinating scientific questions that remain elusive. Here, we chose the apo-state 70S ribosome from Escherichia coli as a model, wherein the 30S subunit undergoes a thermally driven intersubunit rotation and exhibits substantial structural flexibility as well as distinct free energy. We experimentally demonstrate that annealing at a fast cooling rate enhances the 70S ribosome homogeneity and improves local resolution on the 30S subunit. After annealing, the 70S ribosome is in a nonrotated state with respect to corresponding intermediate structures in unannealed or heated ribosomes. Manifold-based analysis further indicates that the annealed 70S ribosome takes a narrow conformational distribution and exhibits a minimum-energy state in the free-energy landscape. Our experimental results offer a facile yet robust approach to enhance protein stability, which is ideal for high-resolution cryogenic electron microscopy. Beyond structure determination, annealing shows great potential for synchronizing proteins on a single-molecule level and can be extended to study protein folding and explore conformational and energy landscapes.

Energy Counterbalance to Harness Photoinduced Structural Planarization of Dibenzo[b,f]azepines toward Thermal Reversibility.

In sharp contrast to most photoinduced structural planarization (PISP) phenomena, which are highly exergonic and irreversible processes, we report here a series of a new class of PISP molecules, 9-phenyl-9H-tribenzo[b,d,f]azepine (PTBA) and its derivatives, where PISP is within the thermally reversible regime. The underlying foundation is the energy counterbalance along PISP, where upon electronic excitation the azepine core chromophore undergoes planarization to gain stabilization from a cyclic 4n π conjugation (n is an integer; Baird's rule). Concurrently, the C7═C8 fused benzene ring is prone to gain aromaticity, which conversely decreases the 4n π-electron resonance stabilization of the 9H-tribenzo[b,d,f]azepine, hindering a full planarization. The offset results in a minimum energy state (P*) along PISP that is in thermal equilibrium with the initially prepared state (R*). The relaxed structure of R* deviates greatly from the planar configuration commonly seen in PISP. PISP of PTBAs is thus sensitive to the solvent polarity, temperature, and substituents, causing prominent stimuli-dependent ratiometric fluorescence for R* versus P*. Exploitation of the energy counterbalance effect proves to be a practical strategy for harnessing excited-state structural relaxation.

Success versus failure: Efficient heat devices in thermodynamics.

Classical equilibrium thermodynamics provides, in a general way, upper Carnot bounds for the performance of energy converters. Nevertheless, to suggest lower bounds is a much more subtle issue, especially when they are related to a definition of convenience. Here, this issue is investigated in a unified way for heat engines, refrigerators, and heat pumps. First, irreversibilities are weighted in the context of heat reservoir stability for irreversible engines by using the thermodynamic distance between minimum energy and maximum entropy steady states. Some stability coefficients can be related to a majorization process and the obtention of Pareto fronts, linking stability and optimization by means of efficiency and entropy due to correlations between system and reservoirs. Second, these findings are interpreted in a very simple context. A region where the heat device is efficient is defined in a general scheme and, below this zone, the heat device is inefficient in the sense that irreversibilities somehow dominate its behavior. These findings allow for a clearer understanding of the role played by some well-known figures of merit in the scope of finite-time and -size optimization. Comparison with experimental results is provided.

Assembly mechanism of surface-functionalized nanocubes.

Faceted nanoparticles can be used as building blocks to assemble nanomaterials with exceptional optical and catalytic properties. Recent studies have shown that surface functionalization of such nanoparticles with organic molecules, polymer chains, or DNA can be used to control the separation distance and orientation of particles within their assemblies. In this study, we computationally investigate the mechanism of assembly of nanocubes grafted with short-chain molecules. Our approach involves computing the interaction free energy landscape of a pair of such nanocubes via Monte Carlo simulations and using the Dijkstra algorithm to determine the minimum free energy pathway connecting key states in the landscape. We find that the assembly pathway of nanocubes is very rugged involving multiple energy barriers and metastable states. Analysis of nanocube configurations along the pathway reveals that the assembly mechanism is dominated by sliding motion of nanocubes relative to each other punctuated by their local dissociation at grafting points involving lineal separation and rolling motions. The height of energy barriers between metastable states depends on factors such as the interaction strength and surface roughness of the nanocubes and the steric repulsion from the grafts. These results imply that the observed assembly configuration of nanocubes depends not only on their globally stable minimum free energy state but also on the assembly pathway leading to this state. The free energy landscapes and assembly pathways presented in this study along with the proposed guidelines for engineering such pathways should be useful to researchers aiming to achieve uniform nanostructures from self-assembly of faceted nanoparticles.

ORBITAL INTERACTIONS AND STABILIZATION ENERGIES OF METHYL 5-6 DIHYDRO BENZO(H) QUINOLINE-4-CARBOXYLATE

Quinolines are aromatic compounds consisting of benzene rings with a pyridine heterocyclic system. In this study, the structure and orbital interactions of the methyl 5-6 dihydro benzo(h) quinolone-4-carboxylate (MDQC) molecule, which is a quinoline derivative, were analyzed. In the calculation using the B3LYP/6-311++g(d,p) level, three conformers were found in the minimum energy state according to the O=C-O-C dihedral angle scan. The energy difference (E+ZPV) between the conformers was calculated ca. 1.9 and 34.8 kJ mol-1, respectively. The relative stability of the conformers was explained using the natural bond orbital (NBO) method and performed. The Fock matrix equation calculated donor and acceptor pairs and orbital energies for NBO pairs for the most stable conformer (MDQC-1). Dominant orbital interactions of selected NBOs for MDQC-1 were calculated at the theory level B3LYP/6-311++g(d,p) and plotted. The molecular electrostatic potential (MEP) surfaces were calculated by the DFT/B3LYP/6-311++g(d,p) method and drawn. NBO charges were calculated for MDQC-1 and MDQC-2 and analyzed.

Grain boundary plane rotation analysis for FCC bicrystal structures using MD simulation

Grain boundary (GB) plane rotation, one of the GB engineering mechanisms, was investigated using the activation–relaxation technique by molecular dynamics simulation. The simulation systems considered in this work are bicrystals with Lennard-Jones-type interatomic potential. The systems of four GB types established are symmetric (SYM), asymmetric (ASYM), symmetric zigzag (SZ), and high-angle zigzag (HZ) models. Of the first two models, [Formula: see text]5 (310) for SYM and [Formula: see text] tilted for ASYM particularly provided reference atomic potential energy distributions and structures at minimum energy state at 0 K. The characteristic of SYM is the discrete atomistic potential distributions which are distinct from ASYM. The other two models based on zigzag-like GBs were created by rotating GB planes about [001] at the center of a [Formula: see text]5 (310)[Formula: see text]GB system for the SZ case and a high-angle GB system for the HZ case. Simulation results show that the initially tilted GBs kinetically transferred to relaxed states for shorter-length GBs through a series of curved GBs. The GBs consist of different combinations of order defect segments, amorphous regions, and defect-free regions. A mechanism proposed is the GB plane rotation, the rate of which is structure-dependent. A low-[Formula: see text] coincidence site lattice boundary section can stabilize the systems at a specified metastable state.

Investigation of microscopic mechanisms for water-ice phase change propagation control

The influence of thermodynamic and structural conditions on water-ice phase change process was investigated with consideration of graphene-water surface interactions for fundamental understanding and effective control of freezing propagation. The phase change propagation as well as structural and energetic properties during the phase change were examined by analyzing atomic data from molecular dynamics simulations. The freezing propagation speed is affected by the competition between atomic mobility and thermodynamic driving force for phase change, which causes an optimal temperature for fast ice growth to appear at 252 K. In addition, the water-ice interfacial energy, which depends on the orientation of the water-contacting ice surface, changes interfacial structural stability and thus freezing propagation, i.e., a higher interfacial energy leads to a faster ice propagation. Therefore, we suggest that the water-ice phase change propagation can be controlled by adjusting the orientation of ice crystal. The surface interactions, or graphene-water interactions in this research, affect the energetics near the water-surface interface. The energetic change rearranges the ice crystal or surface structures to reach the most stable ice-surface configuration or minimum energy state, in which the basal plane of the ice crystal is parallel with the graphene surface. As ice propagation is the slowest perpendicular to the basal plane, ice can grow faster parallel to graphene surface. The findings from this study provides insights to ice propagation control mechanisms for versatile freeze casting and its broader applications.

Microstructure and Time-Dependent Behavior of STx-1b Calcium Montmorillonite Suspensions

CaMnt is much less important than NaMnt due to its limited commercial applications. The time-dependent property of NaMnt gel has been studied extensively as it is exploited in many applications such as drilling mud and viscosity-modifier applications. In contrast, the time-dependent property of CaMnt suspension and the factors affecting it are largely unknown. The speciation of Ca2+ ions is one such factor to be evaluated. In the current study, pH and solids concentration were examined and then used to validate a recent theory on clay gel time dependency. The results supported the theory that a strong electrostatic double layer (EDL) repulsion in the 3-D network is needed to reorganize the structure and drive it toward the state of minimum free energy. The 12 wt.% CaMnt (STx-1b) gel displayed time-dependent behavior at pH 5 but not at its natural pH of 8.4. At pH 5, the interlayer Ca2+ ions became fully hydrated and desorbed from the platelet surface. This enhanced the EDL repulsion between the platelets. At pH >6.5, the positively charged hydrolysis product Ca(OH)+ began to form and was adsorbed, partially neutralizing the permanent layer charge and weakening the repulsion. However, at 19.4 wt.% solids, the gel displayed pronounced time-dependent behavior despite the high natural pH of 8. The platelets were much closer together, allowing the EDL force to operate and effect structural reorganization. The microstructure of these CaMnt gels showed high platelet concentrations interacting to form a relatively open structure. The microstructure of a kaolin (KGa-2) suspension which showed no time-dependent behavior even after 1 day of ageing revealed the importance of particle morphology and layer charge on time dependency. Its 3-D structure was formed by relatively thick, layered platelets with a low layer charge.

Ageing behaviour spanning months of NaMt, hectorite and Laponite gels: Surface forces and microstructure – A comprehensive analysis

Recent “artifact-free” microstructure information enabled the development of a more credible model for explaining the ageing time-dependent rheological behavior of NaMt, hectorite and Laponite gels. These gels displayed pronounced ageing behavior lasting months. The platelet morphology and the localised nature of the negative and positive charges produced the essential forces and interaction configurations to form the time-dependent structure. This structure is composed of nano-sized flexible platelets interacting both attractively to form the network junctions and repulsively to open up the structure. These junctions were formed by heterogeneous charge and van der Waals attractions between the jagged and curled edges, and the face of the interacting platelets. The force that is responsible for the time-dependent behaviour is the EDL repulsive force. This force governs the development of the 3-D network structure and drives it towards a minimum free energy state. This process takes a long time to complete. The resultant microstructure is completely interpenetrated with interconnected nanopores trapping as much as 99% of water in volume. At high ionic strength or 0.3 M KCl, the NaMt or bentonite gels became time independent as the van der Waals force formed the structure. The Leong model described the initial ageing behavior well. For the nanodiscotic Laponite gels, the 3-D structure is formed from sheets instead of primarily disks contradicting prevailing model. With the latest microstructure information, new mechanisms were proposed to account for the high yield stress at low solids, low permeability, intercalation behavior, layer stacking and enlarged dried platelets.

Fabrication of freeform optical components by fluidic shaping

Freeform optical components enable advanced manipulation of light that is not possible with traditional optical systems. However, their fabrication relies on machining processes that are complex, time-consuming, and require significant infrastructure. Here we present the ability to shape liquid volumes and solidify them into desired freeform components, enabling rapid prototyping of freeform components with high surface quality. The method is based on controlling the minimum energy state of the interface between a curable optical liquid and an immersion liquid, by dictating a geometrical boundary constraint. We provide an analytical solution for the resulting topography given a predefined boundary and demonstrate the fabrication of freeform components with sub-nanometer surface roughness within minutes. Such a fabrication capability, that allows for rapid prototyping of high-quality components, has the potential to answer an unmet need in the optical design industry—allowing researchers and engineers to rapidly test freeform design concepts. It can be further envisioned to be expanded to an industrial scale, allowing for mold-less fabrication of freeform optics.

On the non-existence of stepped-pressure equilibria far from symmetry

The Stepped Pressure Equilibrium Code (SPEC) (Hudson et al 2012 Phys. Plasmas 19 112502) has been successful in the construction of equilibria in 3D configurations that contain a mixture of flux surfaces, islands and chaotic magnetic field lines. In this model, the plasma is sliced into sub-volumes separated by ideal interfaces, and in each volume the magnetic field is a Beltrami field. In the cases where the system is far from possessing a continuous symmetry, such as in stellarators, the existence of solutions to a stepped-pressure equilibrium with given constraints, such as a multi-region relaxed MHD minimum energy state, is not guaranteed but is often taken for granted. Using SPEC, we have studied two different scenarios in which a solution fails to exist in a slab with analytic boundary perturbations. We found that with a large boundary perturbation, a certain interface becomes fractal, corresponding to the break up of a Kolmogorov–Arnold–Moser (KAM) surface. Moreover, an interface can only support a maximum pressure jump while a solution of the magnetic field consistent with the force balance condition can be found. An interface closer to break-up can support a smaller pressure jump. We discovered that the pressure jump can push the interface closer to being non-smooth through force balance, thus significantly decreasing the maximum pressure it can support. Our work shows that a convergence study must be performed on a SPEC equilibrium with interfaces close to break-up. These results may also provide insights into the choice of interfaces and have applications in finding out the maximum pressure a machine can support.

Asymmetric Propellant Positioning in Symmetric Tanks and Propellant Management Devices

Dangers of assuming symmetric liquid and gas positioning in symmetric tanks with symmetric propellant management device vanes are identified. Examples from spaceflight history plus modeling of proposed designs illustrate the issue in numerous geometries. Spaceflight hardware and research geometries present the same behavior: that the minimum-energy state for static positioning of liquid and gas in a partially filled vessel with axial symmetry or with, for example, fourfold symmetry of propellant management device vanes need not be symmetric. Because it is simple to assume a symmetric solution, the reality of the nonsymmetric solution may surface as a potentially crippling anomaly in spaceflight or in 0 research operations. Altered mass properties and thermal response of tanks to heaters are two important changes that nonsymmetric liquid positioning can produce. The surprises are avoidable by ground-based analysis and modeling that consider the possibility of such solutions.

Inverse chemical equilibrium problems: General formulation and algorithm

In a forward chemical equilibrium problem (FCEP), the state of minimum Gibbs energy for a chemical system is sought, in which temperature, pressure, elemental amounts, and thermodynamic model parameters are prescribed. We herein present a mathematical framework for characterizing and solving inverse chemical equilibrium problems (ICEP), a class of problems for which one or more of those prescribed conditions in a FCEP are unknown in advance. In an ICEP, complementary conditions must be imposed, which are referred to here as equilibrium constraints. Examples of ICEPs include those in which a certain property is known at equilibrium (e.g., volume is specified instead of pressure; enthalpy is specified instead of temperature; pH is specified instead of the amount of element H). The equilibrium constraints may also be specified by equations that govern the relationship between several equilibrium properties (e.g., the equations relating temperature, pressure, density, energy, and velocity of the gases produced during the detonation of an explosive).

Enhancing magnetorheology through the directed self-assembly under toggled magnetic fields in saturation

The yield stress in magnetorheological (MR) fluids is enhanced through their directed self-assembly under toggled (unsteady) magnetic fields. Experimental yield stress data are compared to previous experiments from the literature involving continuous (DC) fields in a wide range of particle concentrations at magnetic saturation using a double-gap magnetorheometer. Data generated with toggled fields are closer to theoretical predictions than conventional DC fields suggesting that generated structures under toggled fields are gap-spanning and closer to minimum energy state configurations. Experiments are in good agreement with particle level simulations.

Guide field effects on the distribution of plasmoids in multiple scale reconnection

The effects of a finite guide field on the distribution of plasmoids in high-Lundquist-number current sheets undergoing magnetic reconnection in large plasmas are investigated with statistical models. Merging of plasmoids is taken into account either assuming that guide field flux is conserved resulting in nonforce-free profiles in general, or that magnetic helicity is conserved and Taylor relaxation occurs to convert part of the summed guide field flux into reconnecting field flux toward minimum energy states resulting in force-free profiles. It is found that the plasmoid distribution in terms of reconnecting field flux follows a power law with index 7/4 or 1 depending on whether merger frequencies are independent of or dependent on their relative velocity to the outflow speed, respectively. This result is approximately the same for the force-free and nonforce-free models, with nonforce-free models exhibiting indices of 2 and 1 for the same velocity dependencies. Distributions in terms of guide field flux yield indices of 3/2 for the nonforce-free model regardless of velocity dependence. This is notably distinct from the indices of 11/8 and 1 for the force-free models independent of and dependent on velocity, respectively. At low guide field fluxes, the force-free models exhibit a second power law index of 1/2 due to nonconstant flux growth rates. The velocity-dependent force-free model predicts the production of slightly more rapidly moving large guide field flux plasmoids which are supported by observational evidence of flux ropes with strong core fields. Implications are discussed on particle acceleration via Fermi processes.

Atomic Stripe Formation in Infinite-Layer Cuprates.

High-temperature superconductivity appears in cuprate materials that have been tuned in a way where the copper–oxygen bond configuration and coordination is in a state of minimal energy. In competition with the Jahn–Teller effect, which impedes the formation of infinitely connected CuO2 planes, the state of minimal energy persists for planar copper–oxygen bond length variations of up to 10%. We have synthesized the infinite-layer phases of CaCuO2 and SrCuO2 as single-crystalline films using molecular beam epitaxy and performed in-plane scanning transmission electron microscopy mapping. For the infinite-layer phase of CaCuO2 with a short Cu–O bond length, the CuO2 planes maintain their minimal energy by forming distinguished atomic stripes. In contrast, atomic stripe formation does not occur in the infinite-layer phase of SrCuO2, which has a larger Cu–O bond length. The polar field provided by the charge reservoir layer in cuprates with infinitely connected CuO2 planes holds the key over the emergence of superconductivity and is vital to maintain infinitely connected CuO2 planes themselves.