Maze-like Pattern Research Articles

Microstructure, microchemistry, and micro-magnetism of Dy grain boundary diffused (Nd, Ce)–Fe–B magnets

The microstructure of (Nd, Ce)–Fe–B sintered magnets with different diffusion depths was characterized by a magnetic force microscope, and the relationship between the magnetic properties and the local structure of grain boundary diffused magnets is discussed. The domains perpendicular to the c-axis (easy magnetization direction) show a typical maze-like pattern, while those parallel to the c-axis show the characteristics of plate domains. The significant gradient change is shown in the concentration of Dy with the direction of diffusion from the surface to the interior. Dy diffuses along grain boundaries and (Dy, Nd)2Fe14B layer with a high anisotropy field formed around the grains. Through in-situ electron probe micro-analysis/magnetic force microscopy (EPMA/MFM), it is found that the average domain width decreases, and the proportion of single domain grains increases as diffusion depth increases. This is caused by both the change of concentration and distribution of Dy. The grain boundary diffusion process changes the microstructure and microchemistry inside the magnet, and these local magnetism differences can be reflected by the configuration of the magnetic domain structure.

Magnetic properties, crystalline and magnetic microstructures of dual-main-phase (Nd, Ce)-Fe-B sintered magnets

The (Nd, Ce)-Fe-B sintered magnets were prepared by a dual-main-phase (DMP) process under the same conditions using different combinations of Nd-Fe-B with Ce-Fe-B and (Nd, Ce)-Fe-B strips. The crystalline and magnetic microstructures of DMP (Nd, Ce)-Fe-B magnets with the remanence of 11.92–12.68 kGs, the intrinsic coercivity of 3.97–5.31 kOe, and the maximum energy product of 23.08–32.99 MGOe have been investigated. Magnetic force microscope (MFM) investigations reveal that the DMP (Nd, Ce)-Fe-B magnets show maze-like patterns, which are like that of standard anisotropy Nd-Fe-B sintered magnets by and large. However, much finer domain structures mixing with coarse ones can be observed obviously in DMP (Nd, Ce)-Fe-B sintered magnets. The size distribution of the domain width of the DMP (Nd, Ce)-Fe-B magnet is not uniform obviously. The average domain width is W = 0.912 μm, and the fine domain width has only 0.216 μm. The smaller domain width and more branch domain patterns exist in poorer coercivity DMP magnets. This is caused by the non-uniform Ce composition of poorer property DMP magnets and the grain boundary microstructure that is not conducive to improving the coercivity. Furthermore, it is found that some domains of rare-earth-rich grain boundary phases exhibit the characteristics of plate-like patterns rather than no-contrast by using MFM, indicating their ferromagnetism. Obvious correlations between the crystalline microstructure, chemical composition of phases, and magnetic structure were demonstrated for the DMP magnets.

Hybrid space filling curve metamaterials for transmissive flow in Jet Engine inlets

Acoustic metamaterials research has grown exponentially in the past 10 years driven by the advances in manufacturing and an increased understanding of damaging environment noise. 2050 was the first noise reduction target as set by Advisory Council for Aircraft Research and Innovation in Europe with a relative 65% decrease. This ambitions target will not be met by current engine noise control technology; however, metamaterials offer an encouraging alternative. Space Filling Curves (SFC) have the potential to provide a lightweight, thin, high performance acoustic liner. SFC have a history in mathematical geometry dating back to the 1890's but are a comparatively new addition to acoustics. They are designed with a sub-wavelength curled cross-section creating a maze-like pattern which slows acoustic wave propagation through the liner, enabling characteristics such as negative refraction and low frequency attenuation. This paper contains unique hybrid designs combining some of the most promising SFC metamaterial acoustic liner designs, in terms of the fundamental theory of the design category and a discussion of the reflection, absorption and transmission characteristics in terms of a grazing flow conditions. Experimental impedance tube testing compares 3D printed designs to the traditional Helmholtz resonator. The paper concludes with future application for aeroacoustics with particular focus on the engine inlet.

Assessment of Choroidal Vasculature and Innate Immune Cells in the Eyes of Albino and Pigmented Mice.

The visualization of choroidal vasculature and innate immune cells in the eyes of pigmented mice has been challenging due to the presence of a retinal pigment epithelium (RPE) layer separating the choroid and retina. Here, we established methods for visualizing the choroidal macrophages, mast cells, and vasculature in eyes of albino and pigmented mice using cell type-specific staining. We were able to visualize the choroidal arterial and venous systems. An arterial circle around the optic nerve was found in mice similar to the Zinn–Haller arterial circle that exists in humans and primates. Three different structural patterns of choriocapillaris were observed throughout the whole choroid: honeycomb-like, maze-like, and finger-like patterns. Choroidal mast cells were relatively few but dense around the optic nerve. Mast cell distribution in the middle and periphery was different among strains. Macrophages were found in all layers of the choroid. Thus, utilizing the simple and reliable methods described herein will allow the evaluation of transgenic and preclinical mouse models of ocular diseases that affect the choroid, including age-related macular degeneration (AMD), diabetic choroidopathy, and retinopathy of prematurity. These studies will advance our understanding of the pathophysiology, and molecular and cellular mechanisms that can be targeted therapeutically, in these diseases.

Magnetic Domain Structure of Galfenol at Elevated Temperatures

Galfenol (iron–gallium) has a great potential in MEMS applications owing to its high magnetostriction constant, low saturation field, and resilience to bending, compressive, and tensile loading. Here, we report on the expansion/shift of the topography and the expansion/shift of the magnetic domain structure of galfenol observed at high temperatures via atomic force microscopy (AFM) and magnetic force microscopy (MFM). The maze-like domain pattern and stripe-like domain pattern are observed in the perpendicular and parallel surfaces. The spike and reverse domains are observed in 3-D view via XEI imaging software. A MATLAB-based stereological method was used to obtain the domain width and domain wall energy density. An increase in domain width and decrease in domain wall energy density was identified when temperature increased from room temperature to 150 °C.

Acoustic space filling curve metamaterials for grazing flow in Jet engine inlets

Acoustic metamaterials research has grown exponentially in the past 10 years driven by the advances in manufacturing and an increased understanding of damaging environment noise. 2020 was the first noise reduction target as set by Advisory Council for Aircraft Research and Innovation in Europe with a relative 50% decrease. This was missed by current Jet engine noise control technology; however, metamaterials offer an encouraging alternative. Space Filling Curves (SFC) have the potential to provide a lightweight, thin, high performance acoustic liner. SFC have a history in mathematical geometry dating back to the 1890's but are a comparatively new addition to acoustics. They are designed with a sub-wavelength curled cross-section creating a maze-like pattern which slows acoustic wave propagation through the liner enabling characteristics such as negative refraction and low frequency attenuation. This paper contains a comparison of some of the most promising SFC metamaterial acoustic liner designs, in terms of the fundamental theory of the design category and a discussion of the reflection, absorption and transmission characteristics in terms of a grazing flow conditions. Computer simulation and impedance tube based experimental testing compares the designs. The paper concludes with future application for aeroacoustics with particular focus on the engine inlet.

Stochastic contraction of myosin minifilaments drives evolution of microridge protrusion patterns in epithelial cells.

Actin-based protrusions vary in morphology, stability, and arrangement on cell surfaces. Microridges are laterally elongated protrusions on mucosal epithelial cells, where they form evenly spaced, mazelike patterns that dynamically remodel by fission and fusion. To characterize how microridges form their highly ordered, subcellular patterns and investigate the mechanisms driving fission and fusion, we imaged microridges in the maturing skin of zebrafish larvae. After their initial development, microridge spacing and alignment became increasingly well ordered. Imaging F-actin and non-muscle myosin II (NMII) revealed that microridge fission and fusion were associated with local NMII activity in the apical cortex. Inhibiting NMII blocked fission and fusion rearrangements, reduced microridge density, and altered microridge spacing. High-resolution imaging allowed us to image individual NMII minifilaments in the apical cortex of cells in live animals, revealing that minifilaments are tethered to protrusions and often connect adjacent microridges. NMII minifilaments connecting the ends of two microridges fused them together, whereas minifilaments oriented perpendicular to microridges severed them or pulled them closer together. These findings demonstrate that as cells mature, cortical NMII activity orchestrates a remodeling process that creates an increasingly orderly microridge arrangement.

Comprehensive Phase Field Study on Directionally-Solidified MoSi<sub>2</sub>/Mo<sub>5</sub>Si<sub>3</sub> Eutectic Alloy

MoSi2/Mo5Si3 eutectic composites have been considered as one of the promising candidates for ultra-high temperature structural applications owing to their high melting point, good oxidation resistance, and low mass density. Their mechanical properties can be improved by controlling the eutectic structure (i.e. script lamellar structure) in directional solidification. It is important to elucidate the dominant factors underlining the unique pattern formation. We conducted a comprehensive phase field study to examine the influence of various factors on the MoSi2/Mo5Si3 eutectic microstructure with complicated morphology. First, the inclined lamellae have been attributed to the minimization of elastic strain energy due to the lattice mismatch between MoSi2 and Mo5Si3, which are partially relaxed by forming semi-coherent phase boundaries. Second, the maze-like pattern on the horizontal cross-section appeared when a two-fold anisotropy of interfacial energy is superimposed on the MoSi2/Mo5Si3 boundary. Third, the random and intersected lamellae have been obtained by assuming the instability of the solid-liquid interface and introducing successive nucleation of Mo5Si3 phase. These findings provide guidance for manipulating the eutectic structure and act as footsteps for further theoretical investigation.

Surface and electronic structure of antiferromagnetic axion insulator candidate EuIn<sub>2</sub>As<sub>2</sub>

The interplay between non-trivial band topology and magnetic order can induce exotic quantum phenomena, such as the quantum anomalous Hall effect and axion insulator state. A prevalent approach to realizing such topological states is either by magnetic doping or through heterostructure engineering, while the former will bring in inhomogeneity and the latter requires complex procedures. Intrinsic magnetic topological insulators are expected to avoid the aforementioned disadvantages, which is of great significance in both studying and practically using these exotic quantum phenomena. Recently, a Zintl compound EuIn<sub>2</sub>As<sub>2</sub> is predicted to be an intrinsic antiferromagnetic axion insulator. The bulk magnetic order of EuIn<sub>2</sub>As<sub>2</sub> has been reported in a lot of experiments, while the topological nature has not yet been confirmed. The surface properties of intrinsic magnetic topological insulators play an important role in the interplay between magnetic order and non-trivial surface state. Here in this work, we study the surface structure and electronic property of EuIn<sub>2</sub>As<sub>2</sub> single crystal by using scanning tunneling microscopy/spectroscopy (STM/S) and non-contact atomic force microscopy (NC-AFM). Considering the strength of bonds, the easy cleavage plane of the crystals possibly lies between In-In layers or between Eu-As layers. The STM topographies show that the cleaved surface is dominated by a striped pattern. And the dominated step height is an integer multiple of <i>c</i>/2, which implies that only one kind of cleavage plane is preferred. Atomic-resolved surface topographies show that the striped pattern is the <inline-formula><tex-math id="M2">\begin{document}$ 1\times 2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20210783_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20210783_M2.png"/></alternatives></inline-formula> surface reconstruction with 50% coverage. Hence an In-terminated surface which will be 100% coverage is ruled out. The spatial evolution of STS near vacancies on the striped pattern shows a hole-doping feature. All of these results reveal that the striped pattern is the <inline-formula><tex-math id="M3">\begin{document}$ 1\times 2 $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20210783_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="18-20210783_M3.png"/></alternatives></inline-formula> surface reconstruction of the Eu terminated surface with 50% coverage. Using the STS, we measure the local densities of states on the striped surface at various temperatures. We find that there is an asymmetric valley-peak feature in the density of states near the Fermi energy at 4 K, which is gradually weakened with increasing temperature, and disappears above the antiferromagnetic Néel temperature, indicating that the asymmetric valley-peak feature is closely related to the antiferromagnetic order. Besides, a maze-like pattern is observed occasionally near some step edges. The STM topographies show atoms both on bright and dark stripes of the maze-like pattern, which form a whole hexagonal lattice. And the NC-AFM images show that the maze-like pattern is about 1 Å higher than the Eu terminated striped pattern. Based on these results, the maze-like pattern can be explained as the buckled Eu surface with 100% coverage. These results provide important information for understanding the surface electronic band structure and topological nature of EuIn<sub>2</sub>As<sub>2</sub>.

Keratins and the plakin family cytolinker proteins control the length of epithelial microridge protrusions.

Actin filaments and microtubules create diverse cellular protrusions, but intermediate filaments, the strongest and most stable cytoskeletal elements, are not known to directly participate in the formation of protrusions. Here we show that keratin intermediate filaments directly regulate the morphogenesis of microridges, elongated protrusions arranged in elaborate maze-like patterns on the surface of mucosal epithelial cells. We found that microridges on zebrafish skin cells contained both actin and keratin filaments. Keratin filaments stabilized microridges, and overexpressing keratins lengthened them. Envoplakin and periplakin, plakin family cytolinkers that bind F-actin and keratins, localized to microridges, and were required for their morphogenesis. Strikingly, plakin protein levels directly dictate microridge length. An actin-binding domain of periplakin was required to initiate microridge morphogenesis, whereas periplakin-keratin binding was required to elongate microridges. These findings separate microridge morphogenesis into distinct steps, expand our understanding of intermediate filament functions, and identify microridges as protrusions that integrate actin and intermediate filaments.

Cortical contraction drives the 3D patterning of epithelial cell surfaces.

Cellular protrusions create complex cell surface topographies, but biomechanical mechanisms regulating their formation and arrangement are largely unknown. To study how protrusions form, we focused on the morphogenesis of microridges, elongated actin-based structures that are arranged in maze-like patterns on the apical surfaces of zebrafish skin cells. Microridges form by accreting simple finger-like precursors. Live imaging demonstrated that microridge morphogenesis is linked to apical constriction. A nonmuscle myosin II (NMII) reporter revealed pulsatile contractions of the actomyosin cortex, and inhibiting NMII blocked apical constriction and microridge formation. A biomechanical model suggested that contraction reduces surface tension to permit the fusion of precursors into microridges. Indeed, reducing surface tension with hyperosmolar media promoted microridge formation. In anisotropically stretched cells, microridges formed by precursor fusion along the stretch axis, which computational modeling explained as a consequence of stretch-induced cortical flow. Collectively, our results demonstrate how contraction within the 2D plane of the cortex can pattern 3D cell surfaces.

A maze-like path generation scheme for fused deposition modeling

Additive manufacturing has the potential to provide novel solutions for fabricating complex structures. However, one of the main obstacles for such methods is the anisotropic mechanical properties of the manufactured product, which hinder the popularization of additive manufacturing in modern industries. Here, a simple yet versatile algorithm is introduced to produce isotropic products via optimizing the printing path. In this method, the workpiece is first separated into distinct areas in terms of the printing sequence, which increases the efficiency of the fabrication process. Subsequently, the printing path is schemed in each sub-region to allow a short extrusion length and low number of start-stop processes. Finally, this maze-like printing path is revised through a series of tensile tests and fracture surface analyses to validate the isotropy. Bending and indentation tests demonstrate that the samples present distinguished properties in terms of strength and isotropy in mechanical properties. Moreover, numerical and physical tests are implemented for validating the advantage of this maze-like pattern in preventing warping caused by residual stress. This work may play a significant role in printing molds that require isotropic properties.

Ultrastructural changes in fin epithelium of Channa punctatus (Bloch) exposed to mercuric chloride: sem study

ABSTRACTFish skin is in direct contact with water and forms the first line of defense against pathogens and toxicants present in the surrounding water. The effect of mercuric chloride (HgCl2) on surface architecture of the epidermis of caudal fin of an air breathing fish, Channa punctatus was examined by scanning electron microscopy (SEM) and revealed the presence of microridges that formed intricate, maze-like patterns. The exposed fish showed significant alterations including disorganization of microridge pattern and increase in number as well as enlargement of mucus cell openings. These findings exhibited concentration- and time- dependent alterations in fin epithelium. Data demonstrated that fin epithelium of fish may be successfully employed as a bioindicator of water pollution.

Preparation and electro-catalytic activity of nanoporous palladium by dealloying rapidly-quenched Al70Pd17Fe13 quasicrystalline alloy

Abstract The formation of nanoporous Pd was studied by electro-chemical dealloying a rapidly-quenched Al70Pd17Fe13 quasicrystal alloy in dilute NaCl aqueous solution, and the electro-catalytic activity of the nanoporous Pd towards methanol electro-oxidation was evaluated by cyclic voltammetry in 1 mol/L KOH solution. XRD and TEM analyses revealed that nano-decomposition of quasicrystal grains occurred in the initial stage of dealloying, and the fully dealloyed sample was composed of FCC-Pd phase. Scanning electron microscopy observation indicated that a maze-like nanoporous pattern was formed in the dealloyed sample, consisting of percolated pores of 5−20 nm in diameter in a skeleton of randomly-orientated Pd nano-ligaments with a uniform thickness of ~5 nm. A retention of ~12 at.% Al in the Pd nano-ligments was determined by energy dispersive X-ray spectroscopy (EDS). The nanoporous Pd demonstrated obvious electro-catalytic activity towards methanol electro-oxidation in alkaline environment.

Control of domain structure and magnetization reversal in thick Co/Pt multilayers

We present a study of the magnetic properties of ${[\mathrm{Co}(3.0\phantom{\rule{0.16em}{0ex}}\mathrm{nm})/\mathrm{Pt}(0.6\phantom{\rule{0.16em}{0ex}}\mathrm{nm})]}_{N}$ multilayers as a function of Co/Pt bilayer repetitions N. Magnetometry investigation reveals that samples with $N\ensuremath{\ge}15$ exhibit two characteristic magnetization reversal mechanisms, giving rise to two different morphologies of the remanent domain pattern. For applied magnetic field angles near the in-plane field orientation, the magnetization reversal proceeds via a spontaneous instability of the uniform magnetic state resulting in perpendicular stripe domains. Conversely, for field angles close to the out-of-plane orientation, the reversal occurs via domain nucleation and propagation leading to a mazelike domain pattern at remanence. Our measurements further enable the characterization of the N-dependent energy balance between the magnetic anisotropy and magnetostatic energy contributions, revealing a gradual disappearance of the domain nucleation process during magnetization reversal for N 14. This leads to the exclusive occurrence of an instability reversal mechanism for all field orientations as well as alignedlike stripe domains at remanence. Furthermore, a detailed study of the influence of the magnetic history allows the determination of a range of material properties and magnetic field strengths, where a lattice of bubble domains with remarkably high density is stabilized. These modulations of the ferromagnetic order parameter are found to strongly depend on N, in terms of center-to-center bubble distance as well as of bubble diameter. Moreover, such Co/Pt multilayers could be utilized to engineer field reconfigurable bubble domain lattices, which resemble magnonic crystals.

Maximum a posteriori-based depth sensing with a single-shot maze pattern.

This study addressed the general problem of correspondence retrieval for single-shot depth sensing where the coded features cannot be detected perfectly. The traditional correspondence retrieval technique can be regarded as maximum likelihood estimation with a uniform distribution prior assumption, which may lead to mismatches for two types of insignificant features: 1) incomplete features that cannot be detected completely because of edges, tiny objects, and many depth variations, etc.; and 2) distorted features disturbed by environmental noise. To overcome the drawback of the uniform distribution assumption, we propose a maximum a posteriori estimation-based correspondence retrieval method that uses the significant features as priors to estimate the weak or missing features. We also propose a novel monochromatic maze-like pattern, which is more robust to ambient illumination and the colors in scenes than the traditional patterns. Our experimental results demonstrate that the proposed system performs better than the popular RGB-D cameras and traditional single-shot techniques in terms of accuracy and robustness, especially with challenging scenes.

Study on the domain structure and tunable spin orientation in L11-CoPt/NiFe exchange springs with Ta-spacer

In this study, we investigate the domain structure and tunable spin orientation in L11-CoPt(10nm)/NiFe(tNiFe) with insertion of 2-nm thick Ta-spacer and by varying NiFe-layer thickness, tNiFe=1.0, 2.5, 5.5, 7.0, 8.5 and 10nm. The L11-CoPt layer exhibits a strong perpendicular magnetic anisotropy and NiFe holds in-plane magnetic anisotropy and both were separated by the non-magnetic Ta-spacer. Upon increasing tNiFe, the magnetic hysteresis loops become more and more tilted along with moderate decrease in both Hc⊥, and SQR⊥ values; while the estimated tilt angle magnetization (θM) values tend to increase from 0 to 60°. Interestingly, with the insertion of Ta-spacer, significant enhancement in θM (=45°) is achieved with tNiFe of ∼3nm in the CoPt/NiFe layers – indicating that increase in tNiFe induces tilting of CoPt spins even in the presence of Ta-spacer. Magnetic force microscopy studies on the the L11-CoPt/Ta/NiFe films revealed maze-like domain patterns and their magnetic phase contrasts tend to decrease with dominant topographic features upon increasing tNiFe. The results obtained with the micro-magnetic simulation on the tilt in anisotropy axis are found to be consistent with the experimental values of θM.

Surface modification of F82H steel exposed to low energy, high flux He plasmas

Polished F82H steel samples were exposed to He plasmas with an ion incident energy of ~80 eV at 773–873 K to three central exposure fluences: 6 × 1024, 1 × 1025 and 4 × 1025 He m−2. Pinholes with diameters less than 70 nm are densely distributed on all exposed samples, resulting from the formation and bursting of blisters. Further, tendril-like features in maze-like patterns on the top of terrace-like ridges are visible for the sample exposed to 4 × 1025 He m−2 in the beam center. EDS indicates that the tendrils are tungsten enriched. Voids with different sizes and shapes with a depth up to 3.5 µm are observed across the sample exposed to 1 × 1025 He m−2. Over the area exposed to a fluence of up to 2 × 1024 He m−2, variations of wavy morphology and blisters are also observed, which could correlate with the crystallographic orientation at the surface. These He pre-exposed F82H steel samples were subsequently subjected to the conditions near the plasma edge in the EAST tokamak for 367 D plasma pulses of varied durations. It is found that the tendril-like features are partially destroyed by these plasma exposures. These results suggest that the properties of the material likely undergo substantial changes due to expected plasma exposure in a tokamak environment. The bursting of blisters and erosion of W-enriched tendrils would introduce additional impurities that could negatively influence the operation of a fusion device.

Role of Ta-spacer layer on tuning the tilt angle magnetic anisotropy of L11-CoPt/Ta/NiFe exchange springs

L11-CoPt/Ta/NiFe trilayers are chosen as model films for probing the role of spacer layer on tuning the tilt angle magnetization (θM) in such exchange springs. For this purpose, a non-magnetic layer (Ta) with varying thickness (tTa) from 0 to 2.5nm was inserted between 10-nm thick CoPt film exhibiting strong perpendicular magnetic anisotropy (PMA) and 4-nm thick NiFe film having in-plane magnetic anisotropy (IMA). With the insertion of Ta-spacer, the magnetic hysteresis loops become more and more tilted as tTa increases. Upon increasing the tTa from 0 to 2.5nm, the estimated SQR⊥ (=Mr⊥/Ms⊥) from the M–H loops is found to decrease moderately; while the θM increases significantly from 43° to 77°. MFM images revealed maze-like domain patterns and the domain size tends to increase at the expense of magnetic phase contrast with increasing tTa. Micro-magnetic simulation of tilt in the anisotropy axis with respect to the bare CoPt-layer showed a trend similar to that of those observed with the M–H loops obtained by VSM measurements. The results of present study suggest that the insertion of Ta-spacer is not only beneficial in terms of preserving the competing anisotropies such as PMA and IMA of CoPt and NiFe-layers respectively through weakened exchange coupling; but also, act as an appropriate means for realizing tunable tilted magnetic anisotropy in the L11-CoPt/NiFe exchange springs.

Inherited structure of amorphous matter

The inherent atomic packing mode of glassy solid is still one of the most interesting and fundamental problems in condensed-matter physics and material science. Although significant progress has been made and provided insights into the atomic-level structure and short-to-medium-range order in glass, the way of leading to the medium-range order is still unclear. Does a universal rule exist in nature to construct a glass structure as what has been discovered for crystals? Is there any connection between glassy and crystalline structures? If so, what does the connection look like and how is the connection related to the properties of the glassy solids? A glassy state is usually obtained through supercooling a liquid fast enough to avoid crystallization. The amorphous nature of glassy solid is experimentally ascertained by X-ray diffraction (XRD), transmission electron microscopy or selected area electron diffraction (SAED). Almost all kinds of glassy solids exhibit similar maze-like SAED patterns without any local lattice fringes and broad diffraction maximum characteristics in XRD data. However, the glassy solids are inherently different in atomic-level structure, demonstrated by their different response behaviors under certain conditions, for example, the diverse annealing-precipitated crystallinephases, the distinct mechanical strengths and ductilities, and the different thermal stabilities against crystallization. Unfortunately, such a difference in inherent structure among glassy solids cannot be easily differentiated from a trivial analysis of the experimental diffraction data. However, the diffraction data such as structure factors or pair correlation functions (PCFs) are not as trivial as they look like. On the contrary, some studies have demonstrated that plenty of structural information is hidden behind the data of structure factors or PCFs, for example, global packing containing both spherical-periodic order and local translational symmetry has been revealed by analyzing PCFs of many metallic glasses. A fractal nature of medium-range order in metallic glassis also found by examining the relationships between the first peak positions in structure factors and atomic molar volumes in many metallic glasses. In fact, the oscillation in the structure factor or PCF is an indication that a certain order does exist in amorphous solid. Therefore, a more careful scrutiny of the diffraction data is desired to gain a more in-depth insight into the glassy structure features and find a clue to unveil the natures of the inherent structures in different glasses. In this paper, we briefly review the recent molecular dynamics simulation results that the distinct hidden orders of atomic packing formula in medium range in these pure glassy solids are unveiled to be inherited from bcc order in glassy Fe and fcc order in glassy Ni, respectively, reflecting nontrivial structural homology between glassy and crystalline solids. By analyzing the partial PCFs of three two-component metallic glasses of CuZr, NiAl, and NiCu which are similar but have distinct glass-forming ability via MD simulations, very different hidden orders are observed in each individual system, indicating that the hidden orders are more complex in multicomponent metallic glasses. The different hidden orders in a multicomponent metallic glass may be entangled topologically. More different hidden orders lead to more complex topological entanglement. Further analysis indicates that the formation of the hidden orders during cooling and their topological entanglement produces the geometrical frustration against crystallization and is closely correlated with the glass-forming ability of metallic alloys. A “genetic map” of hidden orders in metallic glass is finally constructed, which provides new insights into the structural properties and structure-property relationships in metallic glass-forming liquids and glasses.