Compact Lattice Research Articles

VFT and AHP Approach to Selecting the Best Option in Decision-Making at PLN: A Case Study in the Cawang-Gandul Project

PLN EIC is one of PLN’s business units and is responsible for the development of electrical infrastructure in the working area of DKI Jakarta, Banten Province, and its surroundings. One of the national strategic projects included in the PLN is the 500 kV Cawang Baru II/Cililitan-Gandul transmission line project, with a COD target of 2026. The delay in the completion of this project and the non-fulfillment of stakeholders’ expectations will certainly have a broad impact on the operation of the electricity system, the impact on PLN’s financial performance, the social impact, the environmental impact, as well as the direct impact on the performance and image of PLN EIC. This research aims to assist management in making decisions related to the best transmission line design for the Cawang-Gandul project so that project completion can be on time and in accordance with stakeholder expectations. In this research, several methodological approaches were used to gain a broader and more complete understanding. The Problem Tree Analysis approach, combined with brainstorming and structured interview techniques, was used to explore business issues. Two complementary approaches, namely Value-Focused Thinking (VFT) and the Stakeholder Analysis method, are used to formulate stakeholder expectations and will become guidelines for formulating alternative strategies. Using a structured interview technique, 4 alternative strategies were formulated in the form of the transmission line design, namely (1) Compact Lattice Tower, (2) Underground Cable, (3) Combine Design (Compact Lattice Tower + Underground Cable), and (4) Steel Pole Tower. The next methodological approach uses the Analytic Hierarchy Process (AHP) to determine the best transmission line design, which is then analyzed using AHP Super Decision software. The results of this research show that the Underground Cable design is the best design alternative that can be implemented in the Cawang-Gandul project with several advantages, namely minimal social conflict, easy implementation, and a relatively faster work process. The final stage of research is to make an implementation plan.

Deconfinement transitions in three-dimensional compact lattice Abelian Higgs models with multiple-charge scalar fields.

We investigate the nature of the deconfinement transitions in three-dimensional lattice Abelian Higgs models, in which a complex scalar field of integer charge Q≥2 is minimally coupled with a compact U(1) gauge field. Their phase diagram presents two phases separated by a transition line where static charges q, with q<Q, deconfine. We argue that these deconfinement transitions belong to the same universality class as transitions in generic three-dimensional Z_{Q} gauge models. In particular, they are Ising-like for Q=2, of first order for Q=3, and belong to the three-dimensional gauge XY universality class for Q≥4. This general scenario is supported by numerical finite-size scaling analyses of the energy cumulants for Q=2,Q=4, and Q=6.

Cofinitely weak f-supplemented lattices

In this paper, weakly [Formula: see text]-supplemented and cofinitely weak [Formula: see text]-supplemented lattices are introduced and studied. Let [Formula: see text] be an element of [Formula: see text] such that [Formula: see text]. If [Formula: see text] is weakly [Formula: see text]-supplemented and [Formula: see text] is weakly [Formula: see text]-supplemented, then [Formula: see text] is weakly [Formula: see text]-supplemented. A [Formula: see text]-complemented lattice with [Formula: see text]-small [Formula: see text]-radical is weakly [Formula: see text]-supplemented if and only if [Formula: see text] is [Formula: see text]-semilocal. A lattice [Formula: see text] is cofinitely weak [Formula: see text]-supplemented if and only if every maximal element of [Formula: see text] has a weak [Formula: see text]-supplement in [Formula: see text]. If [Formula: see text] is a cofinitely weak [Formula: see text]-supplemented sublattice of a lattice [Formula: see text] and [Formula: see text] has no maximal element, then [Formula: see text] is cofinitely weak [Formula: see text]-supplemented. Let [Formula: see text] be a compactly generated lattice such that for every compact element [Formula: see text] of [Formula: see text], [Formula: see text]. Then [Formula: see text] is cofinitely weak [Formula: see text]-supplemented if and only if [Formula: see text] is cofinitely [Formula: see text]-supplemented. Let [Formula: see text] be a compact lattice such that for every compact element [Formula: see text] of [Formula: see text], [Formula: see text]. Then [Formula: see text] is weakly [Formula: see text]-supplemented if and only if [Formula: see text] is [Formula: see text]-supplemented.

Planar triangular lattice of the LuMgGaO4: Clustered site-occupancy and the upconversion luminescence of the co-doped Er,Yb ions

The ordered and stable structure of inorganic lattice is the basis of constructing high-efficiency rare earth activated fluorescence, solid-state laser or other optical materials. The mixed sensitized and activated rare earth ions usually keeps a uniform space-occupying and the energy transfer depends much on the doping concentration, while the aggregation of rare earth dopants in order is rare. In this work, a series of LuMgGaO4 phosphors were synthesized and the detail lattice parameters are analyzed through Vietveld refinement and the new CIF file is provided. The site-occupancy of Er3+, Yb3+ shows clustered features and the Er–Yb sublattice structure with various Yb/Er ratios were constructed on the basis of planar triangular lattice. The long-distance excitation energy migration to lattice or defects can be effectively inhibited in case of the hexagonal circle Er-6Yb sublattice, in which the most intense green/red UCL was obtained. All the results demonstrate the novelty of regulating ordered site-occupancy of rare earth ions on a compact planar triangular lattice with higher efficiency of energy migration, which will pave a way for developing phosphor-converted materials or laser materials with better performance.

Elettra 2.0: The Vacuum System Design for a New Generation Storage Ring

Next-generation synchrotron facilities currently under development and construction are promising and delivering great advances in terms of machine design and research physics. At the same time, they are pushing the limits of technological solutions for various subsystems: to achieve the desired ultra-low electron beam emittance required in the next generation machines, the magnetic lattice has to adopt a compact design with reduced magnet apertures and other constraints like high heat load from synchrotron radiation, dynamic pressure inside vacuum chambers and chamber wall impedance are presenting unique challenges for the vacuum and engineering teams. At Elettra-Sincrotrone Trieste (Italy), the Elettra 2.0 project aims to develop a new-generation storage ring. Taking into consideration the above-mentioned constraints, we decided to adopt a new design of a vacuum chamber, while utilizing novel pumping solutions to overcome hugely reduced conductance compared to the current machine. Large sputter ion pumps (SIP) will be in the majority replaced by distributed non-evaporable getter (NEG) coatings and small NEG cartridges and SIP pumps. For the synchrotron radiation handling, due to the tight space constraints imposed by the compact lattice, the photon absorption will be managed jointly with discrete and distributed solutions: photon absorbers have been carefully studied for combining compact form and high power density loads, while key sections of the new storage ring will be water-cooled. Throughout the whole development phase, we were using Monte-Carlo simulation codes like SynRad and MolFlow+ as effective tools supporting the design of new vacuum chambers and photon absorbers. The current state of development for the Elettra 2.0 vacuum system, the challenges we faced and the solutions we adopted are presented here.

Design and experimental research of UHV flanges for the Hefei Advanced Light Facility

The Hefei Advanced Light Facility (HALF) is a diffrac-tion-limited storage ring (DLSR) light source based on the compact multi-bend achromat (MBA) lattice. There-fore, the gaps between those focusing magnets are small. The commonly used ConFlat® flange, with a large axis dimension, is not suitable for the compact lattice in HALF. In this work, a stainless steel tapered flange fas-tened by a chain clamp has been designed for its smaller axis dimension. Two types of sealing structures are used, which are knife-edge and spring-energized metal C-ring structures, respectively. The copper gaskets with and without silver coating are used for knife-edge flange, respectively. Besides, the spring-energized metal C-ring is manufactured by SUS 304 with a tin layer of 50 μm. These flanges and chain clamps were made of SUS 304, and their vacuum properties were tested. The results indi-cate that these UHV flanges can meet the demands for the vacuum system of HALF.

A Broadband Biosensor Using Graphene-Metasurface Based Cross-Polarization Converter

We present the design and analysis of a graphene metasurface-based cross polarization converter operating within the terahertz gap for detecting biomolecules over a broad spectral range, taking the SARS-CoV-2 virus as a specific example. To the best of our knowledge, our design reports the widest band of operation in the THz region of a graphene-based metasensor. Each meta-atom comprises a graphene pattern on silicon dioxide atop a continuous gold layer and exhibits near-unity cross polarization conversion ratio (PCR) and a 90% PCR bandwidth of 0.926 THz within the desired band (1.88 THz-2.81 THz). The proposed device demonstrates additional benefits which include a thin configuration ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /7.84) and compact lattice size ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /10.66), which are significantly better than other recently reported graphene metasurface biosensors. The device provides a sensitivity up to 490 GHz/RIU and a figure of merit (FoM) of 0.377 over a wide span of 0.926 THz within the terahertz gap. The electromagnetic response of this device has been validated via rigorous numerical analyses of simulated outputs as well as by developing a detailed circuit model representation of the same. The device demonstrates angular stability of nearly 40° under oblique incidence of the incident wave.

Soot Morphology and Nanostructure Differences between Chinese Aviation Kerosene and Algae-Based Aviation Biofuel in Free Jet Laminar Diffusion Flames.

Aircraft soot has a significant effect on the air quality and human health. The aim of this study is to investigate the evolution of soot morphology in free jet laminar diffusion flames between Chinese traditional aviation kerosene RP-3 and algae-based aviation biofuels. The differences in height, profile, and structural properties of soot between the RP-3 flame and biofuel flame are determined. A laboratory-made probe sampling method was applied for soot sample collection. Transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and elemental analyzers were used to analyze the collected soot particles. The average particle size of soot increases first and then decreases in both flames, and the size of biofuel primary particles is smaller than that of jet fuel RP-3 particles along the same flame height. At the flame tip, the primary particle sizes of RP-3 soot and biofuel soot are 22.7 and 15.6 mm, respectively. In comparison with the RP-3 soot, the nanostructure of biofuel soot particles along the same flame height exhibits a shorter fringe lattice, a larger fringe tortuosity, and a larger interlayer spacing, which indicate a higher degree of oxidation reactivity. Meanwhile, RP-3 soot particles have a lower H/C atom ratio and have greater intensity in X-ray diffraction, which indicates a more orderly and compact lattice structure. This study provides some references in studying the algae-based biofuel with regard to soot formation.

A proof-of-concept model of compact and high-performance 87Sr optical lattice clock for space

A compact and robust design of an optical lattice clock with high stability and accuracy is needed for the implementation of optical clocks operating on the space station. Here, we present the proof-of-concept model of a 87Sr optical lattice clock for space constructed at the National Time Service Center. The design is different from that of a laboratorial optical clock in that it focuses on the aspects of compactness and robustness, such as the modular design, compact components, low power consumption, and all-fiber links. The physics package is placed on an aluminum alloy rack with dimensions of 40 × 55 × 28 cm3. As far as we know, this is the most compact physics package of the Sr optical clock reported. The time interleaved self-comparison frequency instability is determined to be 2.6 × 10−15/τ.

Impact of Cation Stoichiometry on the Crystalline Structure and Superconductivity in Nickelates

The recent discovery of superconductivity in infinite-layer nickelate films has aroused great interest since it provides a new platform to explore the mechanism of high-temperature superconductivity. However, superconductivity only appears in the thin film form and synthesizing superconducting nickelate films is extremely challenging, limiting the in-depth studies on this compound. Here, we explore the critical parameters in the growth of high-quality nickelate films using molecular beam epitaxy. We found that stoichiometry is crucial in optimizing the crystalline structure and realizing superconductivity in nickelate films. In precursor NdNiO3 films, optimal stoichiometry of cations yields the most compact lattice while off-stoichiometry of cations causes obvious lattice expansion, influencing the subsequent topotactic reduction and the emergence of superconductivity in infinite-layer nickelates. Surprisingly, in-situ reflection high energy electron diffraction indicates that some impurity phases always appear once Sr ions are doped into NdNiO3 although the X-ray diffraction data are of high quality. While these impurity phases do not seem to suppress the superconductivity, their impacts on the electronic and magnetic structure deserve further studies. Our work demonstrates and highlights the significance of cation stoichiometry in the superconducting nickelate family.

Transition in the spectral gap of the massless overlap Dirac operator coupled to Abelian fields in three dimensions

The low lying spectrum of the massless overlap Dirac operator coupled to abelian fields in three dimensions with three different measures are shown to exhibit two phases: a strong coupling gapped phase and a weak coupling gapless phase. The vanishing of the gap from the strong coupling side with a Maxwell and a conformal measure is governed by a Gaussian exponent. Contrary to this result, the vanishing of the gap from the strong coupling side with a compact Thirring measure is not consistent with a Gaussian exponent. The low lying spectrum with a non-compact Thirring measure does not exhibit a simple non-monotonic behavior as a function of the lattice size on the weak coupling side. Our combined analysis suggests exploring the possibility of a strongly coupled continuum theory starting from a compact lattice Thirring model where a compact U(1) gauge field with a single link action is coupled to even number of flavors of massless overlap Dirac fermions.

Structural Evolution of Boron Clusters on Ag(111) Surfaces - From Atomic Chains to Triangular Sheets with Hexagonal Holes.

Unlike graphene and other 2D materials, borophene is 2D polymorphic with diverse hexagonal holes (HHs)-triangles ratios and the concentrations of HHs are highly substrate dependent. Here, we systematically explored the evolution of boron cluster on Ag(111) surface, BN @Ag(111) (N=1∼36), to understand the nucleation of 2D boron sheet on metal surface. Our calculation showed that, with the size increasing, the structures of most stable BN clusters undergo an evolution from compact triangular lattice, such as double-chains or triple-chains, to the ones with mixed triangular-hexagonal lattices. The first single-HH appears at N=12 and the first double-HH appears at N=27. The stability of large BN clusters with mixed structures is derived from the charge transfer between triangular lattice and the HHs, as well as between the substrates and the BN clusters. Our results provide a deep understanding on the formation of small boron clusters in the initial nucleation stage of borophene growth.

DNA-assisted assembly of cationic gold nanoparticles: Monte Carlo simulation.

DNA-assisted assembly of ligand-stabilized gold nanoparticles is studied using Monte Carlo simulations with coarse-grained models for DNA and AuNP. Their interaction in a periodic simulation box is described by a combination of electrostatic and pairwise hard core potentials. We first probe the self-assembly of AuNPs resulting in an ordered distribution on a single fixed DNA strand. Subsequently, the effective force calculated between a pair of parallel DNA in the presence of AuNPs shows the attraction between them at short distance associated to a stable equilibrium position. Finally, the osmotic pressure calculated in a compact DNA-AuNP lattice with various amounts of monovalent salt ions shows that an increasing amount of salt prevents aggregate formation.

Higher-charge three-dimensional compact lattice Abelian-Higgs models.

We consider three-dimensional higher-charge multicomponent lattice Abelian-Higgs (AH) models, in which a compact U(1) gauge field is coupled to an N-component complex scalar field with integer charge q, so that they have local U(1) and global SU(N) symmetries. We discuss the dependence of the phase diagram, and the nature of the phase transitions, on the charge q of the scalar field and the number N≥2 of components. We argue that the phase diagram of higher-charge models presents three different phases, related to the condensation of gauge-invariant bilinear scalar fields breaking the global SU(N) symmetry, and to the confinement and deconfinement of external charge-one particles. The transition lines separating the different phases show different features, which also depend on the number N of components. Therefore, the phase diagram of higher-charge models substantially differs from that of unit-charge models, which undergo only transitions driven by the breaking of the global SU(N) symmetry, while the gauge correlations do not play any relevant role. We support the conjectured scenario with numerical results, based on finite-size scaling analyses of Monte Carlo simuations for doubly charged unit-length scalar fields with small and large number of components, i.e., N=2 and N=25.

Effects of CO/H2/N2 addition on the soot morphology and nanostructure in laminar co-flow ethylene diffusion flame

This study investigated the effect of CO/H2/N2 addition on the morphological evolutions and nanostructures of soot generated from a laminar co-flow ethylene diffusion flame through utilizing the method of thermophoretic sampling and transmission electron microscopy (TEM). The additions were introduced into the inner tube along with the fuel stream, and the volume fractions of the additions are 10%, 20% and 30%. Specifically, the parameters of soot production, primary particle diameter (Dp), fractal dimension (Df), fractal pre-factor (kg) and the nanostructures were determined and analyzed. A reduction in soot production was observed with increasing proportion of the additives, demonstrating the addition of these diluent gases could inhibit the soot formation. Among the three additives, N2 is the most effective in reducing soot yield. The size analysis of soot particles and aggregates indicated the addition of CO or N2 could diminish the primary particle diameter and fractal parameters. The addition of H2 could reduce the primary particle diameter at the bottom flame while yields greater primary particles at 40 mm HAB. This result demonstrated that H2 addition may weaken the oxidation occurring on soot particles. High resolution transmission electron microscopy (HRTEM) analysis was also developed and the results showed that the addition of CO or H2 results in greater fringe length, smaller fringe tortuosity and inter-fringe spacing for soot particles, demonstrating the more orderly and compact lattice structure. In particular, the nanostructure parameters of soot particles in H2 enriched flame vary more significantly than those in CO enriched flame, demonstrating the soot nanostructure is more graphitized in H2 enriched flame. Different from the case of CO or H2 addition, the lattice characteristics for soot in the flames with N2 addition present inverse variation tendency.

Crystals of Topological Vortices in Compact Electrodynamics

This study concerns the changes in the topological properties of four-dimensional compact lattice electrodynamics. The requirement of model compactness leads to the appearance of topological defects (monopoles) creating magnetic currents. Available calculations demonstrate the occurrence of a phase transition for the birth of monopoles. In this work, a phase transition between various states has been revealed inside this phase along with some indications to the possibility of a single “monopole” phase to separate into smaller ones, which differ in the order of the arrangement of magnetic currents and their intensity. The regularity of this consideration and the consequences confirming the presence of a second phase transition in the model are substantiated. The dependence of the correlation properties of magnetic currents on the direction is demonstrated. A new method that comprehensively illustrates the changes in currents in different states with the use of geometric construction is proposed for the analysis of phase transitions.

Morphing lattice boom for space applications

Structures used in space applications demand the highest levels of stiffness for their mass whilst also performing in a hostile environment. To partly address these requirements and so as to also pack efficiently for stowage during launch we propose a new type of compact telescopic morphing lattice space boom. This boom stows within a 1U CubeSat volume and is lightweight being only 0.4 kg. The boom has a total length of 2 m in its deployed state which is 20 times its stowed height. The device comprises two multi-stable cylindrical composite lattices that are joined telescopically. These lattices nest inside one another in the stowed configuration, with the objective of improving packaging efficiency. Notably, prestress and lamina orientation are used to smoothly change shape from being compact when stowed to being extended when deployed. The lattices in the boom have been designed to maximise deployment force and to be self-deploying by tuning manufacturing parameters. As a result, only a small, lightweight mechanism is required to regulate deployment speed of the lattice boom. By reversing its direction, this mechanism can be used to retract the lattice boom to its stowed configuration, thereby enabling two-way reconfigurability.

Polarization insensitive penta‐bandstop frequency selective surface for closely placed bands

AbstractThis article reports on a single layer penta‐bandstop frequency selective surface (FSS) for multiband shielding applications. The proposed unit cell incorporates five independent resonant elements that are realized on a single‐sided FR4 substrate to suppress GSM ‐ 0.9 GHz, GPS ‐ 1.5 GHz, GSM ‐ 1.8 GHz, Wi‐Max ‐ 3.5 GHz, and Wireless Local Area Network (WLAN) ‐ 5.7 GHz frequency bands. The proposed single layer unit cell has compact lattice periodicity of order 0.11 λo × 0.11 λo. The design is not only polarization‐insensitive, but it also offers high angular stability up to 45°. A detailed parametric analysis is conducted to establish a relationship between geometrical parameters and FSS spectral response. Additionally, an equivalent lumped circuit model is also derived to further elaborate on the underlying resonance mechanism. A prototype is fabricated and tested to validate the performance of the proposed FSS. The measured results are in good agreement with simulated ones. The proposed FSS has the uniqueness of suppressing 0.9 GHz GSM band that has never been reported in a pentaband design. The proposed FSS is a potential candidate for radio frequency (RF) shielding, electromagnetic wave suppression, and data security applications in secure installations.

Highly efficient and thermally stable narrow-band cyan-emitting aluminum oxynitride phosphor for WLEDs and FEDs

For the extension of the color gamut of filed-emission displays (FEDs) and realizing the narrow-band emission with the broad excitation band, Eu2+ activated aluminum Oxy-nitride, Al9O3N7:Eu2+, was successfully synthesized through the gas pressure sintering. Based on the host lattice of AlN, the new phase of Al9O3N7 can be produced with the introduction of oxygen. Under the high temperature and pressure, O2− ions partially replace the N3− ions and face-/edge- shared Al(O, N)4 tetrahedron are observed in Al9O3N7 through the Rietveld refinement, which builds the compact host lattice. The TEM and SEM image further shows the change of crystal structure and morphology induced by the introduction of the oxygen. Compared with the blue light emission of AlN: Eu2+, Al9O3N7: Eu2+ emits a bright cyan light peaked at 482 nm with FWHM = 67 nm. The broad excitation band ranges from 300 nm to 415 nm with the maximum at 370 nm, which implies that the Al9O3N7: Eu2+ phosphor is well matched with the NUV - LED chips. Moreover, Al9O3N7: Eu2+ exhibits high quantum efficiency (65%) and excellent thermal stability. The bright cathodoluminescence (CL) emission of Al9O3N7: Eu2+ with excellent stability was detected. The results indicate that this kind of aluminum oxy-nitride with the tight crystal structure enriches WLEDs and FEDs used phosphors.

In Situ Proteolysis Condition-Induced Crystallization of the XcpVWX Complex in Different Lattices.

Although prevalent in the determination of protein structures; crystallography always has the bottleneck of obtaining high-quality protein crystals for characterizing a wide range of proteins; especially large protein complexes. Stable fragments or domains of proteins are more readily to crystallize; which prompts the use of in situ proteolysis to remove flexible or unstable structures for improving crystallization and crystal quality. In this work; we investigated the effects of in situ proteolysis by chymotrypsin on the crystallization of the XcpVWX complex from the Type II secretion system of Pseudomonas aeruginosa. Different proteolysis conditions were found to result in two distinct lattices in the same crystallization solution. With a shorter chymotrypsin digestion at a lower concentration; the crystals exhibited a P3 hexagonal lattice that accommodates three complex molecules in one asymmetric unit. By contrast; a longer digestion with chymotrypsin of a 10-fold higher concentration facilitated the formation of a compact P212121 orthorhombic lattice with only one complex molecule in each asymmetric unit. The molecules in the hexagonal lattice have shown high atomic displacement parameter values compared with the ones in the orthorhombic lattice. Taken together; our results clearly demonstrate that different proteolysis conditions can result in the generation of distinct lattices in the same crystallization solution; which can be exploited in order to obtain different crystal forms of a better quality