Investigations of Phonons in Zinc Blende and Wurtzite by Raman Spectroscopy

The importance of phonons and their interactions in bulk materials is well known to those working in the fields of solid‐state physics, solid‐state electronics, optoelectronics, heat transport, quantum electronic, and superconductivity. Phonons in nanostructures may act as a guide to research on dimensionally confined phonons and lead to phonon effects in nanostructures and phonon engineering. In this chapter, we introduce phonons in zinc blende and wurtzite nanocrystals. First, the basic structure of zinc blende and wurtzite is described. Then, phase transformation between zinc blende and wurtzite is presented. The linear chain model of a one‐dimensional diatomic crystal and macroscopic models are also discussed. Basic properties of phonons in wurtzite structure will be considered as well as Raman mode in zinc blende and wurtzite structure. Finally, phonons in ZnSe, Ge, SnS2, MoS2, and Cu2ZnSnS4 nanocrystals are discussed on the basis of the above theory

Evaluation of performance for malaria diagnosis in health facilities by five provincial reference laboratories of China

IntroductionThe provincial malaria diagnosis reference laboratories review and assess malaria cases diagnosed in health facilities for supporting the malaria elimination efforts and preventing re-transmission of imported malaria. The study aimed to evaluate the detection capability of malaria diagnosis in China from 2014 to 2021.MethodsData on malaria cases reported in the provincial-level administrative divisions (PLADs) of Anhui, Henan, Hubei, Guangxi, and Zhejiang from 2014 to 2021 were collected and analyzed.ResultsIn total, 5,770 malaria cases were reported from 2014 to 2021, and 99.05% (5,715/5,770) were submitted to the provincial malaria diagnosis reference laboratories. The median time between malaria cases being reported and the samples being received by reference laboratories was 6 days (Interquartile range, IQR:3–12 days) from 2017 to 2021. Diagnosis of 5,680 samples in the laboratory were confirmed by provincial reference laboratories, including 3,970 cases of Plasmodium falciparum, 414 of P. vivax, 1,055 of P. ovale, 158 of P. malariae, 1 of P. knowlesi, and 82 of mixed infections. Plasmodium species of 5,141 confirmed cases were consistent with the initial diagnosis, with a species accuracy rate of 90.53% (5,141/5,679). The accuracy of P. falciparum diagnosis in health facilities was higher than that of non-falciparum species. The inconsistency between microscopy and nested polymerase chain reaction (nPCR) results of confirmatory diagnosis was mainly in malaria-positive versus malaria-negative cases, as well as in mixed versus single infection cases.ConclusionThe provincial malaria diagnosis reference laboratories have played an important role in ensuring the accuracy and reliability of Plasmodium diagnosis in health facilities. However, the results of this study imply that capacity training for the identification of Plasmodium species in health facilities is warranted

A new method and application of groundwater prediction along the direction of tunnel excavation in karst strata

Tunnel construction in karst strata with abundant water causes changes in the surrounding groundwater environment, which can easily trigger geological disasters such as mud and water inrush. How to accurately predict the groundwater ahead of tunnel excavation face is a highly challenging problem. In order to improve the detection accuracy of groundwater during the construction of a deep buried tunnel, the transmission and reflection process of seismic waves at the interface and the relationship between the reflection coefficient and seismic wave signal have been analyzed on the basis of a two-phase medium theory in this paper. The expression of seismic wave stress–response relationship associated with the instantaneous amplitude and instantaneous phase and frequency is established. Then the relationship between seismic wave attributes and groundwater seepage potential energy is derived by combining the fluid mechanics theory, which is used as the basis for the determination and identification of groundwater volume and classified, and a new technology of an advanced detection of groundwater by seismic waves is established. This method has been applied to the Zhanghuai Railway in China and quantitatively predicted the karst water and caves in the Tianqiaoshan Tunnel before excavation. The engineering test proves the reliability and advancement of this technology. HIGHLIGHTS The relationship between seismic wave information and surrounding rock stress change is established.; The relationship between groundwater seepage and disturbance stress change variable of surrounding rock under the action of seismic wave is proposed.; The method of fine detection of groundwater by artificial seismic waves is proposed and verified.

Formation of twins in AlON material and its effects on the Vickers hardness and fracture toughness

Aluminum oxynitride (γ-AlON) powders were synchronously synthesized by carbothermal reduction-nitridation (CRN) and high-temperature solid state reaction (SSR) methods. Twin structures existing in γ-AlON powders and transparent AlON ceramics were investigated by systematically employing electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). It was found that the twin structures in synthetic powder and transparent ceramics exhibit quite different microstructural features; binary twin structures were widely observed in powders and ceramics, whereas the sandwich-like twin structure was produced only in transparent ceramics. High-resolution electron backscattered diffraction (HREBSD) was used to determine the residual elastic stress distributions in AlON powders and ceramics. Discrepancies in the magnitude and distribution of the residual stress between binary twins and sandwich-like twins were fully clarified. The formation of two kinds of twins in powders and ceramics was discussed in detail. The Vickers hardness and its corresponding indentation size effect (ISE) were studied in CRN-AlON and SSR-AlON ceramics. The effects of the twin structure on the Vickers hardness and fracture toughness were investigated simultaneously

Imported and indigenous <i>Plasmodium Vivax</i> and <i>Plasmodium Falciparum</i> malaria in the Hubei Province of China, 2005-2019

Background: the Hubei Province in China reported its last indigenous malaria case in September 2012, but imported malaria cases, particularly those related to Plasmodium vivax and Plasmodium falciparum, threaten Hubei's malaria-free status. This study investigated the epidemiological changes in P. vivax and P. falciparum malaria in this province to provide scientific evidence for preventing malaria resurgence.Methods: The prevalence, demographic characteristics, seasonal features, and geographical distribution of malaria were assessed using surveillance data and were compared across three stages: control stage (2005-2009) and elimination stages I (2010-2014) and II (2015-2019).Results: In 2005-2019, 8483 malaria cases were reported, including 5599 indigenous P. vivax cases, 275 imported P. vivax cases, 866 imported P. falciparum cases, and 1743 other cases. Imported P. falciparum cases accounted for 0.07% of all cases reported in 2005, but increased to 78.81% in 2019. Most imported P. vivax and P. falciparum malaria occurred among males, aged 21-60 years, during elimination stages I and II. The number of regions affected by imported P. falciparum and P. vivax increased markedly in Hubei from the control stage to elimination stage II. Overall, 1125 imported P. vivax and P. falciparum cases were detected from 47 other nations. Eight imported cases were detected from other provinces in China. From the control stage to elimination stage II, the number of cases of malaria imported from African countries increased, and that of cases imported from Southeast Asian countries decreased.Conclusions: Although Hubei has achieved malaria elimination, it faces challenges in maintaining this status. Hence, imported malaria surveillance need to be strengthened to reduce the risk of malaria re-introduction.</p

Characterization of micro‐mechanical properties of AlON ceramic by cantilever bending test

The AlON transparent ceramic cantilever beams containing twin and grain boundaries were fabricated by focused ion beam (FIB) technique. The deformation behaviors were investigated by measurement of the load and displacement dependence of cantilever beams from micro bending tests. Young’s modulus of AlON transparent ceramics was calculated from load and displacement curves, the results of which were consistent with results of previous works. Moreover, the bonding strengths of twin lamella boundary, twin boundary and normal grain boundary in AlON transparent ceramics were 5.00 GPa, 5.05 GPa and 4.81 GPa respectively