Based on the tunable conductivity of silicon as a function of incident pump power, a photoexcited switchable dual-function metamaterial absorber for sensing and wideband absorption at the THz band is designed in this paper. The absorber has an absorption peak at 2.08 THz with the absorption up to 99.6% when the conductivity of silicon is 150 Sm⁻¹, which can be used for sensing. The refractive index sensitivity of the absorption peak is up to 456 GHz/RIU. A wideband absorption is generated from 3.4 THz to 4.5 THz with the bandwidth of 1.1 THz as the conductivity σ_si = 12,000 Sm⁻¹. The generation mechanism of the sensing absorption peak and wideband absorption is explained by monitoring the surface current, electric, and magnetic field distribution at some absorption frequencies. It has the advantages of being simple and having a high sensitivity, and wideband absorption with wide application prospects on terahertz communication, electromagnetic stealth, and biochemical detection.

We demonstrate a thermally controlled ultra-wideband wide incident angle metamaterial absorber with switchable transmission at the THz band in this paper. The underlying hybrid structure of FSS-VO₂ thin films make them switchable between absorption mode and transmission mode by controlling the temperature. It can achieve ultra-wideband absorption with above 90% absorption from 1 THz to 10 THz and exhibits excellent absorption performance under a wide range of incident and polarization angles at a high temperature (80 °C). At room temperature (27 °C), it acts in transmission mode with a transmission coefficient of up to 60% at 3.1278 THz. The transmission region is inside the absorption band, which is very important for practical applications. The metamaterial absorber has the advantage of easy fabrication, an ultra-wideband, a wide incident angle, switchable multi-functions, and passivity with wide application prospects on terahertz communication and radar devices.

A mechanically controlled switchable wideband frequency–selective rasorber/absorber, with the transmission window inside the absorption band, based on a frequency–selective surface and a rotatable metal plate, is presented in this paper. The absorption of the switchable rasorber/absorber is over 90%, from 3.9 GHz to 11.77 GHz, when the rotatable metal plate is parallel to the rest of the layers, and its transmission coefficient can reach up to 0.62 at 11.6 GHz, with the rotatable metal plate perpendicular to the rest of the layers. The mechanism of wideband absorption and transmission are explained by monitoring and analyzing the surface current distribution at the absorption and transmission frequencies. The control method is simple, reliable and accurate. It has application value in communication and radar stations.

The paper takes two manufacturing enterprises, Huawei and Sany Heavy Industry, as the research objects, takes the financial reports and relevant data of companies from 2017 to 2021 as the data sources, and studies the impact of digital transformation on the performance of the company's. The research found that digital transformation improves the innovation ability of the company. To some extent, it improves the operation efficiency of the enterprise, expands the income source channel of the enterprise, and improves the business performance of the enterprise. However, it is also found that leading enterprises do not perform in some financial indicators, especially when the external operating environment deteriorated, and the benefits brought by digital transformation cannot completely offset the losses caused by these uncertain factors.