Conformal Surface Research Articles

The α-D-anomer of 2'-deoxycytidine: crystal structure, nucleoside conformation and Hirshfeld surface analysis.

β-2'-Deoxyribonucleosides are the constituents of nucleic acids, whereas their anomeric α-analogues are rarely found in nature. Moreover, not much information is available on the structural and conformational parameters of α-2'-deoxyribonucleosides. This study reports on the single-crystal X-ray structure of α-2'-deoxycytidine, C9H13N3O4 (1), and the conformational parameters characterizing 1 were determined. The conformation at the glycosylic bond is anti, with χ = 173.4 (2)°, and the sugar residue adopts an almost symmetrical C2'-endo-C3'-exo twist (23T; S-type), with P = 179.7°. Both values lie outside the conformational range usually preferred by α-nucleosides. In addition, the amino group at the nucleobase shows partial double-bond character. This is supported by two separated signals for the amino protons in the 1H NMR spectrum, indicating a hindered rotation around the C4-N4 bond and a relatively short C-N bond in the solid state. Crystal packing is controlled by N-H...O and O-H...O contacts between the nucleobase and sugar moieties. Moreover, two weak C-H...N contacts (C1'-H1' and C3'-H3'A) are observed. A Hirshfeld surface analysis was carried out and the results support the intermolecular interactions observed by the X-ray analysis.

Conductive Electrifi and Nonconductive NinjaFlex Filaments based Flexible Microstrip Antenna for Changing Conformal Surface Applications

As the usage of wireless technology grows, it demands more complex architectures and conformal geometries, making the manufacturing of radio frequency (RF) systems challenging and expensive. The incorporation of emerging alternative manufacturing technologies, like additive manufacturing (AM), could consequently be a unique and cost-effective solution for flexible RF and microwave circuits and devices. This work presents manufacturing methodologies of 3D-printed conformal microstrip antennas made of a commercially available conductive filament, Electrifi, as the conductive trace on a commercially available nonconductive filament, NinjaFlex, as the substrate using the fused filament fabrication (FFF) method of AM technology. Additionally, a complete high frequency characterization of the prototyped antenna was studied and presented here through a comparative analysis between full-wave simulation and measurements in a fully calibrated anechoic chamber. The prototyped antenna measures 65.55 × 55.55 × 1.2 mm3 in size and the measured results show that the 3D-printed Electrifi based patch antenna achieved very good impedance matching at a resonant frequency of 2.4 GHz and a maximum antenna gain of −2.78 dBi. Finally, conformality performances of the developed antenna were demonstrated by placing the antenna prototype on five different cylindrical curved surfaces for possible implementation in flexible electronics, smart communications, and radar applications.

In situ small-angle X-ray scattering reveals solution phase discharge of Li–O2 batteries with weakly solvating electrolytes

Electrodepositing insulating lithium peroxide (Li2O2) is the key process during discharge of aprotic Li-O2 batteries and determines rate, capacity, and reversibility. Current understanding states that the partition between surface adsorbed and dissolved lithium superoxide governs whether Li2O2 grows as a conformal surface film or larger particles, leading to low or high capacities, respectively. However, better understanding governing factors for Li2O2 packing density and capacity requires structural sensitive in situ metrologies. Here, we establish in situ small- and wide-angle X-ray scattering (SAXS/WAXS) as a suitable method to record the Li2O2 phase evolution with atomic to submicrometer resolution during cycling a custom-built in situ Li-O2 cell. Combined with sophisticated data analysis, SAXS allows retrieving rich quantitative structural information from complex multiphase systems. Surprisingly, we find that features are absent that would point at a Li2O2 surface film formed via two consecutive electron transfers, even in poorly solvating electrolytes thought to be prototypical for surface growth. All scattering data can be modeled by stacks of thin Li2O2 platelets potentially forming large toroidal particles. Li2O2 solution growth is further justified by rotating ring-disk electrode measurements and electron microscopy. Higher discharge overpotentials lead to smaller Li2O2 particles, but there is no transition to an electronically passivating, conformal Li2O2 coating. Hence, mass transport of reactive species rather than electronic transport through a Li2O2 film limits the discharge capacity. Provided that species mobilities and carbon surface areas are high, this allows for high discharge capacities even in weakly solvating electrolytes. The currently accepted Li-O2 reaction mechanism ought to be reconsidered.

Quasi-continuous linear phase-gradient metamaterial based on conformal spoof surface plasmon polaritons

In this work, we propose a method of achieving quasi-continuous linear phase gradient for transmitted waves based on conformal spoof surface plasmon polariton (SSPP). To this end, a SSPP structure with high transmission is firstly designed as the unit cell of the metamaterial. To obtain the phase gradient, SSPP structures are arranged delicately in a way that they are conformal to the brachistochrone curve. In this way, quasi-continuous linear Pancharatnam-Berry (PB) phase profile can be realized strictly along one of the two transverse directions. To verify this idea, a dual-band transmissive metamaterial operating in X and Ku band was designed, fabricated and measured. Due to the phase gradient imparted by the conformal SSPP structures, high-efficiency anomalous refraction can be realized within the two bands. Different from the general PGM, the phase gradient of the conformal SSPP structure allows us to achieve the desired anomalous refraction angle without reconstructing the PB phase. Both the simulation and measurement results are well consistent with theoretical predictions. This work provides another strategy of achieving anomalous refraction and may find applications in beam steering, digital beam forming, etc.

3D Conformal Surface Engineering of Continuous Fibers with Porous Microstructures for 1D Advanced Functional Materials

AbstractOne‐dimensional (1D) continuous advanced functional materials and devices with inherent flexibility for complex deformations facilitate a broad range of applications in wearable technology. This communication presents a new electrostatic self‐assembly strategy for controllable assembly of nanomaterials to fabricate 1D continuous materials with customizable functions based on a kind of continuous fiber fully surface‐engineered with 3D conformal porous microstructures (F@3CPMs) by a unique self‐assembly approach of breath figure using water microdroplet arrays. Through gently rubbing the modified fibers with suitable triboelectric materials, either positively or negatively charged F@3CPMs can be rationally prepared with adjustable triboelectric charge intensity. Besides showing superiority in incorporating desired components, such kind of F@3CPMs are demonstrated to have general applicability and enhanced performance in controllable self‐assembly of polymeric, metal, and carbon nanomaterials for customizable functionalizations. Moreover, taking advantages of continuous fibers that can deform largely, functional F@3CPMs are further applied for development of 1D flexible motion sensing devices by twisting directly, which can be either used as 1D freestanding devices for straightforward integration with conventional fabrics or woven as a fabric structure integrity for a kind of self‐powered interactive textiles without additional battery as power resources to detect and monitor the body motions of human beings.

Facies Analysis and Depositional Stages of The Albian-Aptian Succession in Balad Oil Field, Central Iraq

Carbonate-clastic succession which includes the Shu'aiba, Nahr Umr and Mauddud formations are representing a part of the Barremian-Aptian Sequence (Wasi'a Group). The present study includes three boreholes (Ba-1, 4 and 8) within the Balad Oil Field. The study area is located in central Iraq. This field represents a subsurface anticline with a northwest to southeast direction axis within the Mesopotamian Zone. Eight types of microfacies were recognized in the succession of the Mauddud and Shu’aiba formations. These microfacies represent shallow open marine, restricted and semi-restricted, reef - back reef, deep open marine and basinal depositional environments. While Nahr Umr Formation includes two successions, the first is the upper unit which is characterized by shale dominated rocks and the second is the lower unit which is characterized by sand-dominated rocks. Four major lithofacies were recognized in these two successions, they represent four depositional environments which are distributary channel, bay fill, delta plain and prodelta. The Albian-Aptian sequence was deposited during three cycles overlying the regional unconformity below the Shu’aiba Formation, the Zubair Formation, and ended with local unconformity with the Ahmadi Formation. The first stage is represented by deposition of Shu’aiba Formation during the sea-level rise after regression stage during the Zubair deposition which deposition in delta association facies. The second stage was showed a regressed of deposit the delta system above the shallow open marine of the Shu’aiba Formation, where the succession became characterized by mud-dominated rock with fissile and organic material. The third depositional stage is represented by the continuation of sea-level rise. This transgression leads to the building of carbonate ramp of the Mauddud Formation above the deltaic system of Nahr Umr Formation with a conformable surface. The Mauddud depositional stage was represented by two cycles of transgression succession, where appeared deepening upward in both cycles. The unconformity between these formations have been determined by observing the glauconite mineral and detected by log response in depth 2880m in well Ba-1.

Testing the relationship between marine transgression and evolving island palaeogeography using 3D GIS: an example from the Late Triassic of SW England

The Rhaetian transgression marked a major change in landscape. The Permian and Triassic had been a time of terrestrial conditions across Europe, including much of mainland UK, as well as the North Sea and Irish Sea, represented by red bed clastic successions. Seas flooded across Europe at 205.7 Ma and the shift from terrestrial to marine environments is marked in the UK by the switch from the red beds of the Mercia Mudstone Group to the black mudstones and shelly limestones and sandstones of the Penarth Group. The area around Bristol was marked by a complex landscape in which an archipelago of islands of Carboniferous limestone was formed in the new shallow seas. The application of new methods in geographical information systems allows a detailed exploration of a number of conformable surfaces, the unconformity between the underlying Paleozoic rocks and the overlying Mesozoic strata, as well as levels within the latest Triassic sediments, marking the advance of the sea and interactions with the coeval tectonics, which caused some islands to rise and some basins to descend. The new geographical information system models show a sequence of palaeogeographical reconstructions of the archipelago and relate this to the island tetrapod faunas, which show strong evidence of the species–area effect. Supplementary material: Supplementary tables S1-S6 and 2D island map GIS files are available at https://doi.org/10.6084/m9.figshare.c.5273256

Optimization of Frequency Selective Surfaces for the Design of Electromagnetic Mantle Cloaks

A full optimization procedure that combines the parallel self-adaptive low-high evaluation-evolutionary algorithm with the finite element method-robin boundary condition iteration numerical method is proposed for the design of electromagnetic mantle cloaks enclosing arbitrary objects. The procedure is efficiently applied to optimize an ultrathin, conformal frequency selective surface (FSS), placed around an inhomogeneous dielectric cylinder to be made invisible. Two very different optimal solutions have been found, and this can be a great advantage for the designer using the proposed optimization strategy.

Effect of surface charge conditions of carriers on the immobilization of β-d-glucosidase

In this study, a series of acidic or alkaline polypeptide chains were designed and grafted onto DEG-AM resin using Fmoc solid-phase synthesis to study the relationship between enzyme conformation and carrier surface charge. β-d-glucosidase (βGase) was then immobilized onto these modified carriers by adsorption. Each form of immobilized βGase showed decreasing specific activity compared to that of the free. It could be attributed to both the changes in the enzyme conformation and the decrease in mass transfer efficiency. The optimum temperature of free βGase, DEG@B3-βGase is 55 °C, which of DEG@A3-βGase is 65 °C and they all have the highest activity at pH 5. The Ea values ​​of free βGase, DEG@A3-βGase, and DEG@B3-βGase are 0.546 kJ/mol, 0.224 kJ/mol, and 0.446 kJ/mol, and the Km values were 1.30 mmol/L, 1.44 mmol/L and 2.63 mmol/L, respectively. It shows that free βGase and DEG@A3-βGase are more similar. Meanwhile, the free βGase (1.0 g/L, pH 5.0) stored at 4 °C has a shorter half-life (t1/2), which is only 9 days. However, the half-life of DEG@B3-βGase and DEG@A3-βGase is 20 days and over 60 days, indicating that the negative charged surface was conducive to maintenance of the structure and catalytic property of βGase.

Ultra-Sensitive and Selective Electrochemical Bio-Fluid Biopsy for Oral Cancer Screening.

The early diagnosis of recurrence and metastasis is critically important for decreasing the morbidity and mortality associated with oral cancers. Although liquid biopsy methods hold great promise that provide a successive "time-slice" profile of primary and metastatic oral cancer, the development of non-invasive, rapid, simple, and cost-effective liquid biopsy techniques remains challenging. In this study, an ultrasensitive and selective electrochemical liquid biopsy is developed for oral cancer screening based on tracking trace amounts of cancer biomarker by functionalized asymmetric nano-channels. Detection via antigen-antibody reactions is assayed by evaluating changes in ionic current. Upon the recognition of cancer biomarker antigens in bio-fluids, the inner wall of nano-channel immobilized with the corresponding antibodies undergoes molecular conformation transformation and surface physicochemical changes, which significantly regulate the ion transport through the nano-channel and help achieve sensitivity with a detection limit of 10-12 g mL-1 . Furthermore, owing to the specificity of the monoclonal antibody for the antigen, the nano-channel exhibits high selectivity for the biomarker than for structurally similar biological molecules present in bio-fluids. The effectiveness of this technique is confirmed through the diagnosis of clinical cases of oral squamous cell carcinoma. This study presents a novel diagnostic tool for oral cancer detection in bio-fluids.

A Novel Loaded Tooth Contact Analysis Procedure With Application to Internal–External Straight Bevel Gear Mesh in a Pericyclic Drive

Abstract A comprehensive numerical loaded tooth contact analysis (LTCA) model is proposed for straight bevel gears that exhibit large number of teeth in contact, well beyond the involute line of action limits. This kind of contact is observed when the meshing gears have conformal surfaces, as in a pericyclic mechanical transmission, and is traditionally analyzed using finite element simulations. The pericyclic drive is kinematically similar to an epicyclic bevel gear train and is characterized by load sharing over large number of teeth in an internal–external bevel gear mesh, large shaft angles (175–178 deg), nutational gear motion, and high reduction ratio. The contact region spreads over a large area on the gear tooth flank due to high contacting surface conformity. Thus, a thick plate finite strip method (FSM) was utilized to accurately calculate the gear tooth bending deflection. Based on the tooth deformation calculation model and accounting for initial surface separation, a variational framework is developed to simultaneously solve for load distribution and gear tooth deformation. This is followed by calculation of contact stress, bending stress, mesh stiffness, and transmission error. The results demonstrate the high-power density capabilities of the pericyclic drive and potential for gear noise reduction. The model developed herein is applied with real gear tooth surfaces, as well.

Conformal Voronoi Metasurface Antenna Embedded in a Composite Structural Laminate

This work presents a comparison between two metasurface antennas operating at 10 GHz utilizing either a conventional hexagonal grid (with a continuous distribution of gap dimensions) or a Voronoi partition (utilizing a constant gap dimension). The Voronoi partition was generated using the point-shifting method (proposed by Lee and Sievenpiper) and is (to the authors' knowledge) the first demonstration of this approach in the design of a radiating metasurface antenna. The traditional hexagonal artificial impedance surface (H-AIS) and Voronoi artificial impedance surface (V-AIS) antennas are shown to exhibit near identical surface impedance profiles, insertion loss, radiation efficiency, and realized gain. However, the Voronoi partition can be adapted to follow an arbitrary conformal surface, whereas the hexagonal grid is restricted to a 2-D plane. To reinforce this advantage, a third metasurface antenna on an arbitrary conformal geometry is designed utilizing numerically generated “reference” and “objective” fields. Lastly, the fabrication of all three antennas utilized a unique process that is compatible with conventional aerospace glass fiber-reinforced composite manufacturing. Hence, this work represents a significant step forward in the deployment of truly conformal multifunctional composite structures.

Coarse-grained conformational surface hopping: Methodology and transferability.

Coarse-grained (CG) conformational surface hopping (SH) adapts the concept of multisurface dynamics, initially developed to describe electronic transitions in chemical reactions, to accurately describe classical molecular dynamics at a reduced level. The SH scheme couples distinct conformational basins (states), each described by its own force field (surface), resulting in a significant improvement of the approximation to the many-body potential of mean force [T. Bereau and J. F. Rudzinski, Phys. Rev. Lett. 121, 256002 (2018)]. The present study first describes CG SH in more detail, through both a toy model and a three-bead model of hexane. We further extend the methodology to non-bonded interactions and report its impact on liquid properties. Finally, we investigate the transferability of the surfaces to distinct systems and thermodynamic state points, through a simple tuning of the state probabilities. In particular, applications to variations in temperature and chemical composition show good agreement with reference atomistic calculations, introducing a promising "weak-transferability regime," where CG force fields can be shared across thermodynamic and chemical neighborhoods.

Solution-Processed Ti3 C2 Tx MXene Antennas for Radio-Frequency Communication.

Highly integrated, flexible, and ultrathin wireless communication components are in significant demand due to the explosive growth of portable and wearable electronic devices in the fifth-generation (5G) network era, but only conventional metals meet the requirements for emerging radio-frequency (RF) devices so far. Here, it is reported on Ti3 C2 Tx MXene microstrip transmission lines with low-energy attenuation and patch antennas with high-power radiation at frequencies from 5.6 to 16.4GHz. The radiation efficiency of a 5.5µm thick MXene patch antenna manufactured by spray-coating from aqueous solution reaches 99% at 16.4GHz, which is about the same as that of a standard 35µm thick copper patch antenna at about 15% of its thickness and 7% of the copper weight. MXene outperforms all other materials evaluated for patch antennas to date. Moreover, it is demonstrated that an MXene patch antenna array with integrated feeding circuits on a conformal surface has comparable performance with that of a copper antenna array at 28GHz, which is a target frequency in practical 5G applications. The versatility of MXene antennas in wide frequency ranges coupled with the flexibility, scalability, and ease of solution processing makes MXene promising for integrated RF components in various flexible electronic devices.

Microfacies Analysis and Basin Development of Hartha Formation in East Baghdad Oil field, Central Iraq

The Hartha Formation is one of the important formations deposited during Late Campanian age.
 The present study deals with four boreholes (EB-53, 54, 55 and 56) within the East Baghdad oil field to diagnoses the microfacies and interpret the depositional environments.
 Six major microfacies were recognized in the succession of the Hartha Formation. Their characteristic grain types and depositional texture enabled the recognition of paleoenvironment. There are Orbitoides wackestone-packstone , Orbitoides - miliolid wackestone, Peloidal and Pellets - echinoderm wackestone to packstone, Peloidal wackestone to packstone, Pelletal wackestone to packstone, and Planktonic foraminifera wackestone-packstone.
 Four associations’ facies were recognized in this succession, which are shallow open marine, deep open marine, semi-resricted, and restricted. The distribution of these associations led to the recognition of three major depositional stages in the studied succession.
 The first stage is represented by the semi-restricted facies within the lower part of the Hartha Formation, which is characterized by Orbitoides - miliolid wackestone to the northwest direction and developed to shallow open marine and deep marine to the southeast direction. In the second stage, the sea level was rising to deposit the deep open marine facies represented by planktonic foraminifera wackestone-packstone microfacies above the semi-restricted facies ,where the succession became characterized by Peloidal and Pellets - echinoderm wackestone to packstone microfacies of restricted association. The third stage is represented by the continuation of sea level rise. This caused the building of carbonate ramp of Shiranish Formation above the shallow open marine of Hartha Formation with conformable surface.

Inkjet-/3D-/4D-Printed Perpetual Electronics and Modules: RF and mm-Wave Devices for 5G+, IoT, Smart Agriculture, and Smart Cities Applications

With the revolutionary developments in the fields of millimeter-wave (mm-wave) and Internet of Things (IoT) technologies and the billion devices promised to be implemented by the end of the decade, the realization of inexpensive, low-power, and intelligent systems is highly desirable. Additive manufacturing (AM) is a technology seeing widespread adoption due to its ability to enable rapid prototyping for iterative design; its reduced setup costs, facilitating economic small-batch production; and its ability to significantly reduce waste by-products, resulting in both environmental benefits as well as lower manufacturing costs. On the other hand, current lithography-based manufacturing technologies-a huge contributor to the growing RF and 5G wireless electronics industry-require extensive design verification, have longer turnaround times, and produce harmful byproducts. Although AM can offer time and cost benefits under the correct conditions, among the more impactful demonstrations of the manufacturing technology are the novel topologies enabled by design rules that allow feature sets, including nonorthogonal planes, conformal surfaces, multimaterial deposition, simultaneous thick- and thin-film deposition [1], complex 3D structures, integrated voids, and gradient index materials.

Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead

Reconfigurable intelligent surfaces (RISs) are an emerging transmission technology for application to wireless communications. RISs can be realized in different ways, which include (i) large arrays of inexpensive antennas that are usually spaced half of the wavelength apart; and (ii) metamaterial-based planar or conformal large surfaces whose scattering elements have sizes and inter-distances much smaller than the wavelength. Compared with other transmission technologies, e.g., phased arrays, multi-antenna transmitters, and relays, RISs require the largest number of scattering elements, but each of them needs to be backed by the fewest and least costly components. Also, no power amplifiers are usually needed. For these reasons, RISs constitute a promising software-defined architecture that can be realized at reduced cost, size, weight, and power (C-SWaP design), and are regarded as an enabling technology for realizing the emerging concept of smart radio environments (SREs). In this paper, we (i) introduce the emerging research field of RIS-empowered SREs; (ii) overview the most suitable applications of RISs in wireless networks; (iii) present an electromagnetic-based communication-theoretic framework for analyzing and optimizing metamaterial-based RISs; (iv) provide a comprehensive overview of the current state of research; and (v) discuss the most important research issues to tackle. Owing to the interdisciplinary essence of RIS-empowered SREs, finally, we put forth the need of reconciling and reuniting C. E. Shannon's mathematical theory of communication with G. Green's and J. C. Maxwell's mathematical theories of electromagnetism for appropriately modeling, analyzing, optimizing, and deploying future wireless networks empowered by RISs.

Continuum representation of nonlinear three-dimensional periodic truss networks by on-the-fly homogenization

Thanks to scale-bridging fabrication techniques, truss-based metamaterials have gained both popularity and complexity, ultimately resulting in structural networks whose description based on classical discrete numerical calculations becomes intractable. We here present a framework for the efficient and accurate simulation of large periodic three-dimensional (3D) truss networks undergoing nonlinear deformation (accounting for linear elastic beams undergoing finite rotations). Although the focus is on elastic beams, the method is sufficiently general to extend to inelastic material behavior. Our approach is based on a continuum representation of the truss (and its numerical implementation via finite elements) whose constitutive behavior is obtained from on-the-fly periodic homogenization at the microstructural unit cell level. We pursue a semi-analytical strategy (previously reported only in two dimensions) which admits the analytical calculation of consistent tangents for convergent implicit solution schemes; the extension to 3D – through the addition of torsional deformation modes and the handling of 3D rotations – results in a powerful tool for the prediction of the complex mechanical response of large structural networks. We validate the small-strain response by comparison to analytical solutions, followed by finite-strain benchmarks that compare simulation results to those of fully-resolved discrete calculations. The homogenization of beam unit cells results in a regularized macroscale model with an intrinsic length scale, which manifests especially when modeling bifurcations or localization. We finally apply our approach to macroscopic boundary value problems involving complex-shaped truss metamaterials (with truss unit cells near the body's boundary mapped onto a conformal surface), which reveal only an insignificant effect of boundary layers on the overall mechanical response, again supporting the applicability of our homogenization approach.

Conformal homogeneous spacelike surfaces in 3-dimensional Lorentz space forms

Let M13(c) be an 3-dimensional Lorentz space form and C(M13(c)) denote the conformal transformation group of M13(c). A spacelike surface x:M2→M13(c) is called a conformal homogeneous spacelike surface. If there exists a subgroup G⊂C(M13(c)) such that the orbit G(p)=x(M2),p∈x(M2). In this paper, we classify completely conformal homogeneous spacelike surfaces up to a conformal transformation of M13(c).

Non-adiabatic Dynamics Mechanism in Excited State of Novel UV Protective Sunscreen in Rice: Conical Intersection Promotes Internal Conversion

Ferulic acid and its derivative γ-oryzanol are common in Rice. They have the same molecular skeleton with some sunscreens that used commonly, but there were no reports on them as rice UV protection. In this work, UV absorption and fluorescence emission spectrum are performed to measure ferulic acid and γ-oryzanol effect of fighting with ultraviolet irradiation. We demonstrated that both ferulic acid and γ-oryzanol have good absorption intensity at UVA, UVB and UVC regions, with superior photostability. Furthermore, the optimized molecular conformation and potential energy surfaces (PES) in ground and excited states are obtained by using the time-dependent density functional theory (TD-DFT) method. From the calculation results, it can conclude that their S1 states decay to the S0 state via internal conversion (IC) process at the S1/S0 conical intersection (CI) point of PES followed by trans–cis photoisomerization. For the first time, we elucidated the mechanism of UV protection for ferulic acid and γ-oryzanol as UV protection in rice from our excited state non-adiabatic dynamics.