2-Bromo-4-chloro-6-(cyclo­hexyl­imino­meth­yl)phenol

The title compound, C13H15BrClNO, was prepared by the condensation of equimolar quanti­ties of 3-bromo-5-chloro­salicyl­aldehyde with cyclo­hexyl­amine in methanol. There is an intra­molecular O—H⋯N hydrogen bond in the mol­ecule. The cyclo­hexyl ring adopts a chair conformation

Review on the development of kelp industry in Shandong province: A comparative perspective

Shandong and Fujian are two important provinces regarding the development of the seaweed industry, which shared three-fourths of the national seaweed yield in the year 2020. The present study has analyzed the overall situation of the seaweed industry in Shandong and Fujian provinces by comparing annual output, farming area, and species structure. The current status of Laminaria japonica cultivation in two provinces is also compared to the production process, industrial organization, progress, and innovation. On this foundation, the following development strategies are proposed for the seaweed industry in Shandong Province: (1) change the mindset based on the present industrial basis, (2) retain and transform innovative achievements, (3) enhance the services of associations and organizations and (4) construct brands based on current market share

Reducing symmetry in topology optimization of two-dimensional porous phononic crystals

In this paper we present a comprehensive study on the multi-objective optimization of two-dimensional porous phononic crystals (PnCs) in both square and triangular lattices with the reduced topology symmetry of the unit-cell. The fast non-dominated sorting-based genetic algorithm II is used to perform the optimization, and the Pareto-optimal solutions are obtained. The results demonstrate that the symmetry reduction significantly influences the optimized structures. The physical mechanism of the optimized structures is analyzed. Topology optimization combined with the symmetry reduction can discover new structures and offer new degrees of freedom to design PnC-based devices. Especially, the rotationally symmetrical structures presented here can be utilized to explore and design new chiral metamaterials.Comment: 24 pages, 11 figures in AIP Advances 201

2,3,4-Trihy­droxy­benzoic acid 0.25-hydrate

The asymmetric unit of the title compound, C7H6O5·0.25H2O, contains two mol­ecules of 2,3,4-trihy­droxy­benzoic acid, with similar conformations, and one water mol­ecule which lies on a twofold rotation axis. Both acid mol­ecules are essentially planar [maximum r.m.s deviations = 0.0324 (2) and 0.0542 (3) Å for the two acid molecules]. The mol­ecular conformations are stabilized by intra­molecular O(phenol)—H⋯O(carbox­yl/phenol) inter­actions. A cyclic inter­molecular association is formed between the two acid and one water mol­ecule [graph set R 3 3(12)] involving O—H⋯O hydrogen bonds. The two acid mol­ecules are further linked through a cyclic R 2 2(8) carb­oxy­lic acid hydrogen-bonding association, which together with inter­molecular O—H⋯O hydrogen-bonding inter­actions involving the phenol groups and the water mol­ecule, and weak π–π inter­actions [minimum ring centroid separation = 3.731 (3) Å], give a three-dimensional network

catena-Poly[[diaqua­manganese(II)]-μ-7-oxabicyclo­[2.2.1]heptane-2,3-dicarboxyl­ato]

In the title polymer, [Mn(C8H8O5)(H2O)2]n, the MnII atom is in a distorted octa­hedral coordination mode, binding to the bridging O atom of the bicyclo­heptane unit, two O atoms from corresponding carboxyl­ate groups, one carboxyl­ate O atom from a symmetry-related bridging ligand and two water O atoms. This arrangement leads to the formation of polymeric chains propagating parallel to [001]. The crystal structure is stabilized by several O—H⋯O hydrogen-bonding inter­actions involving the coordinated water mol­ecules as donors and the carboxyl­ate O atoms as acceptors

Health monitoring device design and application for large synchronously excited multi-shaker vibration test facility

There are different kinds of equipments distributed in different locations for a large complicated multi-shaker vibration test facility, so it is challenging to monitor the real state of test facility thoroughly during its operation. Long-term operation of this test facility will lead to the degradation of reliability and malfunction, and sometimes the emergency stop of the whole test system that threatens the safety of the spacecraft seriously. This paper presents in detail the design and application of a set of health monitoring device for a large multi-shaker vibration test facility which is capable of monitoring the operation state in real time and predicting the potential malfunction of the whole test facility to ensure the reliability of this large test system and safety of the spacecraft during its environmental vibration test

Tunable multiband directional electromagnetic scattering from spoof Mie resonant structure

We demonstrate that directional electromagnetic scattering can be realized from a artificial Mie resonant strcuture which supports electric and magnetic dipole modes simultaneously. The directivity of the far-field radiation pattern can be switched by changing the incident light wavelength as well as tailoring the geometric parameters of the structure. Particularly, the electric quadrupole at higher frequency contribute significantly to the scattered fields, leading to enhancement of the directionality. In addition, we further design a quasiperiodic spoof Mie resonant structure by alternately inserting two materials into the slits. The results show that multi-band directional light scattering are realized by exciting multiple electric and magnetic dipole modes with different frequencies in the quasiperiodic structure. The presented design concept is general from microwave to terahertz region and can be applied for various advanced optical devices, such as antenna, metamaterial and metsurface.Comment: 10pages,6figure