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Wet chemical etching is essential not only for processing silicon (Si) wafers but also for forming diverse structures, significantly promoting the development of the semiconductor industry. However, tight control of etched topography at the nanoscale and even atom-scale in a controllable and reproducible fashion can be hardly achieved in either laboratory research or industrial production, seriously hindering further enhancement of high-performance Si-based electronic devices. Herein, the roles of mechanically driven defects in wet etching were systematically investigated toward promoting controllable wet etching of monocrystalline Si. The role of antietching of mechanically driven amorphous Si (a-Si) and the role of promoting etching of distorted Si (including dislocations and stacking faults) were revealed in anisotropic or isotropic etchants. It was also found that the nucleation of nanocrystals in the a-Si area with increasing contact pressure can lead to deactivation of the antietching mask, and the required contact pressure for deactivation in KOH and tetramethyl ammonium hydroxide solutions was much higher than that in HF/HNO3 mixtures. The selective etching mechanisms for every defect including a-Si, distorted Si, and nanocrystals were further addressed down to the atom-scale based on the proposed dissolution model. This study provides insights into deeply understanding the role of defects in wet etching and pushes forward the idea of controllable wet chemical etching in the Si-based semiconductor industry.

Nanoparticle-based therapeutic and detectable modalities can augment anticancer efficiency holding potential in capable target and suppressive metastases post administration. However, individual discrepancies of current “one-size-fits-all” strategies for anticancer nanotherapeutics have...

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Base-isolated buildings subjected to extreme earthquakes or near-fault pulse-like earthquakes can exceed their design gap distance and impact against the surrounding moat wall. Based on equating energy dissipation and maximum collision compression deformation of isolated structure with the Hertz-damp model and Kevin-Voigt model in the process of collision, an equivalent linear impact model (ELIM) is proposed to better predict impact response of seismic isolated structure. The formula of the equivalent linear stiffness of ELIM is theoretically derived. The effectiveness of ELIM is verified by comparing the results of numerical analyses with the results of pounding experiments. Four near-fault earthquakes are selected to validate rationality and accuracy of the proposed model using numerical analysis. The results indicate that the proposed linear model can nearly capture impact behavior of isolated structure in simulating the pounding-involved structural response.

Cold-formed steels have been commonly applied in construction. However, there is a lack of understanding on its post-fire mechanical properties. This paper presents an experimental investigation into the post-fire mechanical properties of cold-formed steels. The test specimens were cut from the flat portion and corners of cold-formed channel sections, which were exposed to temperatures ranging from ambient temperature to 800°C, and then cooled with water and air. The specimens are of grade Q235, and of thickness 1mm and 2mm. The stress-strain curves and mechanical properties of all specimens were obtained from tensile coupon tests. A comparison of mechanical properties between coupon samples cut from flat portion and corners is presented. Moreover, the evolution of microstructure and fracture morphology of specimens after being cooled by air and water were examined. Finally, predictive equations are proposed for evaluating the post-fire mechanical properties of Q235 cold-formed steel channel sections.

such as poor water solubility, [2] low bioavailability, rapid blood clearance, and multidrug resistance. [3] In order to solve these problems, drug delivery systems based on nanocarriers have been extensively developed, which not only increase the drug loading capacity and blood time of the target drug, but also reduce the potential systemic toxicity of the loaded drug. [4] So far, traditional nanocarriers are generally composed of inorganic materials such as carbon-based nanomaterials (CBNs), [5] magnetic particles, [6] silica, [7] gold-based nanomaterials, [8] and organic molecules such as polymer NPs, [9] liposomes, [10] micelles, [11] etc. Among them, CBNs have the characteristics of biocompatibility, low toxicity, high water-solubility, and potential to conjugate various molecules, they have been widely used in drug delivery, cancer diagnosis and therapy, and other fields, and are considered as an excellent nanocarrier. [12] It has been reported that CBNs loaded with DOX can be used to target tumor cell nucleus, but in order to improve the drug targeting rate, it is usually necessary to modify active targeting ligands, such as antibodies, folic acid, and peptides (RGD and nuclear targeting peptides), etc. However, these active targeting ligands have potential drawbacks while improving drug targeting, such as the high cost of antibodies and low tumor penetration due to their large size, the low stability of aptamers due to the nucleases in blood plasma, and the low circulating half-life of The emergence of nanocarriers solves the problems of antitumor drugs such as non-targeting, huge side effects, etc., and has been widely used in tumor therapy. Some kinds of antitumor drugs such as doxorubicin (DOX) mainly act on the nucleic acid causing DNA damage, interfering with transcription, and thereby disrupting or blocking the process of cancer cell replication. Herein, a new nanodrug delivery system, the carbon-based nanomaterials (CBNs)-Pluronic F127-DOX (CPD), is designed by using CBNs as a nanocarrier for DOX. As a result, the tumor growth inhibition rate of CPD group is as high as 79.42 ± 2.83%, and greatly reduces the side effects. The targeting rate of the CPD group of DOX in the tumor nucleus is 36.78%, and the %ID/g in tumor tissue is 30.09%. The CPD regulates the expression levels of Caspase-3, p53, and Bcl-2 genes by increasing intracellular reactive oxygen species (ROS) levels and reducing mitochondrial membrane potential, which indicates that mitochondrial-mediated pathways are involved in apoptosis. The CPD nanodrug delivery system increases the effective accumulation of DOX in tumor cell nuclei and tumor tissues, and generates massive ROS, thereby inhibiting tumor growth in vivo, representing a promising agent for anticancer applications.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smtd.202100539.

Owing to special functional requirements of museum, such as great space and story height for exhibitions, large floor slab openings in plan and long span truss in elevation are becoming increasingly considered in museum design, which leads to challenges to structural safety. The aseismic performance of an isolated museum structure in high earthquake intensity regions was thus studied because of its complexity and irregularity. In order to observe the seismic characteristics and verify isolation effect, shaking table tests of a 1/30-scale structural model with and without base isolation bearings have been carried out under minor, moderate, and major earthquakes. The experimental results show that isolated structure dynamic characteristics and isolation effect are stable and storey peak acceleration responses of superstructure are less than that of fixed structure. Storey drifts of isolated structure meet required limits stipulated in Chinese design code and torsion responses of the bearings are not remarkable. It is suggested that seismic performances of complex museum structures have been effectively improved with isolation in use.