Optical Design of an LCoS-based 1×10 WSS with High Coupling Efficiency and Compact Light Paths

In the field of communication, liquid crystal on silicon (LCoS) wavelength selection switches (WSS) systems are of great significance but the lack of research on its optical path design makes it challenging to realize high-port-count and perfect performance with a compact structure. In this paper, the optical path design method of a compact LCoS-based 1×10 WSS system working in C-band (1529nm~1568nm) is proposed, where there exists 1 input port and 10 output ports in the same array. The distribution of optical power in the two directions is taken into account independently, boosting system compactness, lowering assembly and manufacturing costs. Finally, a high fiber-to-fiber coupling efficiency ranging from 95.07% to 99.18% is achieved, corresponding to ultra-low simulation loss of less than 0.22dB. Furthermore, a brief tolerance analysis to demonstrate the instrumentation feasibility is also conducted. Our work is pioneering in providing a more straightforward evaluation method and a more workable solution for the optical design of WSS systems

Table_11_Complete genome sequence, metabolic model construction, and huangjiu application of Saccharopolyspora rosea A22, a thermophilic, high amylase and glucoamylase actinomycetes.xlsx

Saccharopolyspora is an important microorganism in the fermentation process of wheat qu and huangjiu, yet the mechanisms by which it performs specific functions in huangjiu remain unclear. A strain with high amylase and glucoamylase activities was isolated from wheat qu and identified as Saccharopolyspora rosea (S. rosea) A22. We initially reported the whole genome sequence of S. rosea A22, which comprised a circular chromosome 6,562,638 bp in size with a GC content of 71.71%, and 6,118 protein-coding genes. A functional genomic analysis highlighted regulatory genes involved in adaptive mechanisms to harsh conditions, and in vitro experiments revealed that the growth of S. rosea A22 could be regulated in response to the stress condition. Based on whole-genome sequencing, the first genome-scale metabolic model of S. rosea A22 named iSR1310 was constructed to predict the growth ability on different media with 91% accuracy. Finally, S. rosea A22 was applied to huangjiu fermentation by inoculating raw wheat qu, and the results showed that the total higher alcohol content was reduced by 12.64% compared with the control group. This study has elucidated the tolerance mechanisms and enzyme-producing properties of S. rosea A22 at the genetic level, providing new insights into its application to huangjiu.</p

Data_Sheet_1_Complete genome sequence, metabolic model construction, and huangjiu application of Saccharopolyspora rosea A22, a thermophilic, high amylase and glucoamylase actinomycetes.docx

Saccharopolyspora is an important microorganism in the fermentation process of wheat qu and huangjiu, yet the mechanisms by which it performs specific functions in huangjiu remain unclear. A strain with high amylase and glucoamylase activities was isolated from wheat qu and identified as Saccharopolyspora rosea (S. rosea) A22. We initially reported the whole genome sequence of S. rosea A22, which comprised a circular chromosome 6,562,638 bp in size with a GC content of 71.71%, and 6,118 protein-coding genes. A functional genomic analysis highlighted regulatory genes involved in adaptive mechanisms to harsh conditions, and in vitro experiments revealed that the growth of S. rosea A22 could be regulated in response to the stress condition. Based on whole-genome sequencing, the first genome-scale metabolic model of S. rosea A22 named iSR1310 was constructed to predict the growth ability on different media with 91% accuracy. Finally, S. rosea A22 was applied to huangjiu fermentation by inoculating raw wheat qu, and the results showed that the total higher alcohol content was reduced by 12.64% compared with the control group. This study has elucidated the tolerance mechanisms and enzyme-producing properties of S. rosea A22 at the genetic level, providing new insights into its application to huangjiu.</p

Thinning Segregated Graphene Layers on High Carbon Solubility Substrates of Rhodium Foils by Tuning the Quenching Process

We report the synthesis of large-scale uniform graphene films on high carbon solubility substrates of Rh foils for the first time using an ambient-pressure chemical vapor deposition method. We find that, by increasing the cooling rate in the growth process, the thickness of graphene can be tuned from multilayer to monolayer, resulting from the different segregation amount of carbon atoms from bulk to surface. The growth feature was characterized with scanning electron microscopy, Raman spectra, transmission electron microscopy, and scanning tunneling microscopy. We also find that bilayer or few-layer graphene prefers to stack deviating from the Bernal stacking geometry, with the formation of versatile moiré patterns. On the basis of these results, we put forward a segregation growth mechanism for graphene growth on Rh foils. Of particular importance, we propose that this randomly stacked few-layer graphene can be a model system for exploring some fantastic physical properties such as van Hove singularities

Unravelling Orientation Distribution and Merging Behavior of Monolayer MoS₂ Domains on Sapphire

Monolayer MoS₂ prepared by chemical vapor deposition (CVD) has a highly polycrystalline nature largely because of the coalescence of misoriented domains, which severely hinders its future applications. Identifying and even controlling the orientations of individual domains and understanding their merging behavior therefore hold fundamental significance. In this work, by using single-crystalline sapphire (0001) substrates, we designed the CVD growth of monolayer MoS₂ triangles and their polycrystalline aggregates for such purposes. The obtained triangular MoS₂ domains on sapphire were found to distributively align in two directions, which, as supported by density functional theory calculations, should be attributed to the relatively small fluctuations of the interface binding energy around the two primary orientations. Using dark-field transmission electron microscopy, we further imaged the grain boundaries of the aggregating domains and determined their prevalent armchair crystallographic orientations with respect to the adjacent MoS₂ lattice. The coalescence of individual triangular flakes governed by unique kinetic processes is proposed for the polycrystal formation. These findings are expected to shed light on the controlled MoS₂ growth toward predefined domain orientation and large domain size, thus enabling its versatile applications in next-generation nanoelectronics and optoelectronics

Periodic Modulation of the Doping Level in Striped MoS₂ Superstructures

Although the recently discovered monolayer transition metal dichalcogenides exhibit novel electronic and optical properties, fundamental physical issues such as the quasiparticle bandgap tunability and the substrate effects remain undefined. Herein, we present the report of a quasi-one-dimensional periodically striped superstructure for monolayer MoS₂ on Au(100). The formation of the unique striped superstructure is found to be mainly modulated by the symmetry difference between MoS₂ and Au(100) and their lattice mismatch. More intriguingly, we find that the monolayer MoS₂ is heavily n-doped on the Au(100) facet with a bandgap of 1.3 eV, and the Fermi level is upshifted by ∼0.10 eV on the ridge (∼0.2 eV below the conduction band) in contrast to the valley regions (∼0.3 eV below the conduction band) of the striped patterns after high-temperature sample annealing process. This tunable doping effect is considered to be caused by the different defect densities over the ridge/valley regions of the superstructure. Additionally, an obvious bandgap reduction is observed in the vicinity of the domain boundary for monolayer MoS₂ on Au(100). This work should therefore inspire intensive explorations of adlayer–substrate interactions, the defects, and their effects on band-structure engineering of monolayer MoS₂

Direct Growth of High-Quality Graphene on High‑κ Dielectric SrTiO₃ Substrates

High-quality monolayer graphene was synthesized on high-κ dielectric single crystal SrTiO₃ (STO) substrates by a facile metal-catalyst-free chemical vapor deposition process. The as-grown graphene sample was suitable for fabricating a high performance field-effect transistor (FET), followed by a far lower operation voltage compared to that of a SiO₂-gated FET and carrier motilities of approximately 870–1050 cm²·V^–1·s^–1 in air at rt. The directly grown high-quality graphene on STO makes it a perfect candidate for designing transfer-free, energy-saving, and batch production of FET arrays

Toward Single-Layer Uniform Hexagonal Boron Nitride–Graphene Patchworks with Zigzag Linking Edges

The atomic layer of hybridized hexagonal boron nitride (h-BN) and graphene has attracted a great deal of attention after the pioneering work of P. M. Ajayan et al. on Cu foils because of their unusual electronic properties (Ci, L. J.; et al. Nat. Mater. 2010, 9, 430−435). However, many fundamental issues are still not clear, including the in-plane atomic continuity as well as the edge type at the boundary of hybridized h-BN and graphene domains. To clarify these issues, we have successfully grown a perfect single-layer h-BN-graphene (BNC) patchwork on a selected Rh(111) substrate, via a two-step patching growth approach. With the ideal sample, we convinced that at the in-plane linking interface, graphene and h-BN can be linked perfectly at an atomic scale. More importantly, we found that zigzag linking edges were preferably formed, as demonstrated by atomic-scale scanning tunneling microscopy images, which was also theoretically verified using density functional theory calculations. We believe the experimental and theoretical works are of particular importance to obtain a fundamental understanding of the BNC hybrid and to establish a deliberate structural control targeting high-performance electronic and spintronic devices

Dendritic, Transferable, Strictly Monolayer MoS₂ Flakes Synthesized on SrTiO₃ Single Crystals for Efficient Electrocatalytic Applications

Controllable synthesis of macroscopically uniform, high-quality monolayer MoS₂ is crucial for harnessing its great potential in optoelectronics, electrocatalysis, and energy storage. To date, triangular MoS₂ single crystals or their polycrystalline aggregates have been synthesized on insulating substrates of SiO₂/Si, mica, sapphire, <i>etc.</i>, <i>via</i> portable chemical vapor deposition methods. Herein, we report a controllable synthesis of dendritic, strictly monolayer MoS₂ flakes possessing tunable degrees of fractal shape on a specific insulator, SrTiO₃. Interestingly, the dendritic monolayer MoS₂, characterized by abundant edges, can be transferred intact onto Au foil electrodes and serve as ideal electrocatalysts for hydrogen evolution reaction, reflected by a rather low Tafel slope of ∼73 mV/decade among CVD-grown two-dimensional MoS₂ flakes. In addition, we reveal that centimeter-scale uniform, strictly monolayer MoS₂ films consisting of relatively compact domains can also be obtained, offering insights into promising applications such as flexible energy conversion/harvesting and optoelectronics

Controllable Growth and Transfer of Monolayer MoS₂ on Au Foils and Its Potential Application in Hydrogen Evolution Reaction

Controllable synthesis of monolayer MoS₂ is essential for fulfilling the application potentials of MoS₂ in optoelectronics and valleytronics, <i>etc.</i> Herein, we report the scalable growth of high quality, domain size tunable (edge length from ∼200 nm to 50 μm), strictly monolayer MoS₂ flakes or even complete films on commercially available Au foils, <i>via</i> low pressure chemical vapor deposition method. The as-grown MoS₂ samples can be transferred onto arbitrary substrates like SiO₂/Si and quartz with a perfect preservation of the crystal quality, thus probably facilitating its versatile applications. Of particular interest, the nanosized triangular MoS₂ flakes on Au foils are proven to be excellent electrocatalysts for hydrogen evolution reaction, featured by a rather low Tafel slope (61 mV/decade) and a relative high exchange current density (38.1 μA/cm²). The excellent electron coupling between MoS₂ and Au foils is considered to account for the extraordinary hydrogen evolution reaction activity. Our work reports the synthesis of monolayer MoS₂ when introducing metal foils as substrates, and presents sound proof that monolayer MoS₂ assembled on a well selected electrode can manifest a hydrogen evolution reaction property comparable with that of nanoparticles or few-layer MoS₂ electrocatalysts