Far-Field Tunable Nano-focusing Based on Metallic Slits Surrounded with Nonlinear-Variant Widths and Linear-Variant Depths of Circular Dielectric Grating

In this work, we design a new tunable nanofocusing lens by the linear-variant depths and nonlinear-variant widths of circular grating for far field practical applications. The constructively interference of cylindrical surface plasmon launched by the subwavelength metallic structure can form a subdiffraction-limited focus, and the focal length of the this structures can be adjusted if the each groove depth and width of circular grating are arranged in traced profile. According to the numerical calculation, the range of focusing points shift is much more than other plasmonic lens, and the relative phase of emitting light scattered by surface plasmon coupling circular grating can be modulated by the nonlinear-variant width and linear-variant depth. The simulation result indicates that the different relative phase of emitting light lead to variant focal length. We firstly show a unique phenomenon for the linear-variant depths and nonlinear-variant widths of circular grating that the positive change and negative change of the depths and widths of grooves can result in different of variation trend between relative phases and focal lengths. These results paved the road for utilizing the plasmonic lens in high-density optical storage, nanolithography, superresolution optical microscopic imaging, optical trapping, and sensing.Comment: 14pages,9figure

Intervention study of finger-movement exercises and finger weight-lift training for improvement of handgrip strength among the very elderly

AbstractObjectivesTo examine the effects of finger-movement exercises and finger weight-lift training on handgrip strength and Activities of Daily Living Scale (ADLS) values.MethodsA total of 80 very elderly adults (aged ≥80 years) were assigned to either an intervention group (n = 40) or a control group (n = 40). Subjects in the intervention group performed finger-movement exercises and weight-lift training for a period of 3 months, while subjects in the control group received no intervention, and were unaware of the interventions received in the other group.ResultsAfter completing 3 months of finger-movement exercises and weight-lift training, the average handgrip strength of the 40 participants in the intervention group had increased by 2.1 kg, whereas that in the control group decreased by 0.27 kg (P < 0.05). After receiving intervention, the number of subjects in the intervention group with an ADLS score >22 points decreased by 7.5% (P < 0.05, vs. pre-intervention).ConclusionsThe combined use intervention with finger-movement exercises and proper finger weight-lift training improved the handgrip strength and ADLS values of very elderly individuals. These rehabilitation exercises may be used to help the elderly maintain their self-care abilities

Radiative thermal switch via metamaterials made of vanadium dioxide-coated nanoparticles

In this work, a thermal switch is proposed based on the phase-change material vanadium dioxide (VO2) within the framework of near-field radiative heat transfer (NFRHT). The radiative thermal switch consists of two metamaterials filled with core-shell nanoparticles, with the shell made of VO2. Compared to traditional VO2 slabs, the proposed switch exhibits a more than 2-times increase in the switching ratio, reaching as high as 90.29% with a 100 nm vacuum gap. The improved switching effect is attributed to the capability of the VO2 shell to couple with the core, greatly enhancing heat transfer with the insulating VO2, while blocking the motivation of the core in the metallic state of VO2. As a result, this efficiently enlarges the difference in photonic characteristics between the insulating and metallic states of the structure, thereby improving the ability to rectify the NFRHT. The proposed switch opens pathways for active control of NFRHT and holds practical significance for developing thermal photon-based logic circuits

Observation of forbidden phonons and dark excitons by resonance Raman scattering in few-layer WS2_2

The optical properties of the two-dimensional (2D) crystals are dominated by tightly bound electron-hole pairs (excitons) and lattice vibration modes (phonons). The exciton-phonon interaction is fundamentally important to understand the optical properties of 2D materials and thus help develop emerging 2D crystal based optoelectronic devices. Here, we presented the excitonic resonant Raman scattering (RRS) spectra of few-layer WS$_2$ excited by 11 lasers lines covered all of A, B and C exciton transition energies at different sample temperatures from 4 to 300 K. As a result, we are not only able to probe the forbidden phonon modes unobserved in ordinary Raman scattering, but also can determine the bright and dark state fine structures of 1s A exciton. In particular, we also observed the quantum interference between low-energy discrete phonon and exciton continuum under resonant excitation. Our works pave a way to understand the exciton-phonon coupling and many-body effects in 2D materials.Comment: 14 pages, 11 figure

(E)-Methyl N′-[1-(4-methoxy­phen­yl)ethyl­idene]hydrazinecarboxyl­ate

The mol­ecule of the title compound, C11H14N2O3, adopts a trans configuration with respect to the C=N bond. The dihedral angle between the benzene ring and the hydrazinecarboxyl­ate plane is 12.06 (9)°. Mol­ecules are linked into a one-dimensional network by N—H⋯O hydrogen bonds and C—H⋯π inter­actions. The benzene rings of inversion-related mol­ecules are stacked with their centroids separated by 3.777 (1) Å, indicating π–π inter­actions

Overview of Contraindicated Chinese Medicines for Pregnancy

Chinese medicines should be classified into drugs, which have both beneficial and harmful effects. For centuries, Chinese medicines have been widely used to relieve many symptoms and to treat complications during pregnancy. It is not clear how safe the Chinese medicines are being used during pregnancy and if there is any adverse effects to embryo-fetal development and prenatal and postnatal growth. Some Chinese medicines are indicated that they cannot be used in pregnancy. In this chapter, we will conduct a systematic review to summarize and characterize in details the Chinese medicines classified as contraindicated, not recommended and cautiously used for pregnancy in most updated version of Pharmacopeia of the People’s Republic of China. Clinical reports including clinical trials, case reports, case series and animal studies including short-term and long-term toxicity, specific organ toxicity and different species of the Chinese medicines will be studied. Unlike those pharmaceutical drugs not recommend for use during pregnancy because of known or suspected adverse or teratogenic effects evident by animal studies and/or clinical trials, most of the Chinese medicines were utilized for long history in culture which, however, has very limited scientific data regarding the adverse pregnant outcomes