Search

The material compositions, preparation strategies and growth techniques of metal halide perovskite single crystals for photodetection application are systematically summarized.

Key villages of rural tourism have become an important carrier for the high-quality development of rural tourism. The precise identification of the spatial distribution characteristics and influencing factors of rural tourism key villages is of great value in promoting the quality upgrading of rural tourism in China and realizing the goal of rural revitalization strategy. The aim is to realize the complementary coordination and integration of urban and rural areas, promote rural transformation and increase farmers’ incomes. Taking three batches of 1199 key rural tourism villages in China as research samples, the nearest neighbor index, disequilibrium index and kernel density methods were used to reveal the spatial differentiation characteristics of key rural tourism villages and the influencing factors were further analyzed using the geographical connection rate and buffer analysis. The results showed that (1) the key villages of rural tourism demonstrated a typical agglomeration in the spatial distribution, with the Hu Huanyong line as the obvious boundary. (2) The very high-density agglomeration centers were mainly located in the Beijing–Tianjin–Hebei region and the Yangtze River Delta region, while the high-density agglomeration zones were mainly located in the North China Plain on the east side of the Taihang Mountains and the middle and lower reaches of the Yangtze River Basin. (3) The spatial distribution characteristics of hot regions were in the central and eastern regions; however, the cold regions were in the northwest and northeast regions. (4) The spatial distribution characteristics of key rural tourism villages were the result of the interaction and coupling of multiple factors. The key villages of rural tourism were mainly distributed in plain and hilly areas with dense river networks, dense populations, high levels of economic development, developed transportation and suburban areas.

It is well-known that the absorbing property of materials is related to the microstructure and can be enhanced by magnetic nanoparticles coating. However, the mechanism is still unclear that the magnetic coating structure plays an important role in the microwave absorption behavior. Hence, a novel kind of absorber with efficient performance and relatively clear enhancement mechanism is very necessary. To solve these problems, polyaniline@MoS2 nanowires (PANI@MoS2 NWS) and a series of polyaniline@MoS2@Fe3O4 nanowires (PANI@MoS2@Fe3O4 NWS) with hierarchical structure were successfully prepared by in situ polymerization and versatile hydrothermal reactions and investigated in microwave absorption. The results reveal that compared with the articles related to MoS2-based composites, the as-prepared PANI@MoS2@Fe3O4 NWS (e2) displays the widest absorption frequency range (6.48 GHz) and strong absorption (−49.7 dB at a thickness of 1.3 mm), and the excellent MAP can be interpreted by optimizing impedance matching...

The development of electronic makes increasing attentions focus on the high thermally conductive polymer composites. In this work, outstanding epoxy nanocomposites embedded with 3D structure fillers of silver nanowires@SiO2 and graphite nanoplatelets are prepared successfully. Insulative SiO2 layers coating on the surface of silver nanowires can not only provide abundant silicon hydroxyl groups to react and form strong covalent bonding with epoxy matrix and graphite nanoplatelets, minimizing the scattering of phonon and contributing to construction of thermally conductive network, but also effectively protect electrical insulation from the forming of electrical conductive pathways. An ultrahigh thermal conductivity of nanocomposites 1.092 W/m K, an enhancement of 474% to pristine epoxy, is achieved only with low filler volume fraction of 0.8 vol% silver nanowires@SiO2 and 2.7 vol% graphite nanoplatelets, at the same time, an ultralow volume conductivity less than 1 × 10−5 S/cm is available at the frequency range 1 × 102Hz to 1 × 106Hz, which indicates strong potential in the field of electronic packaging.

An excellent PPy/NiFe2O4/CS microwave absorbing materials with a three-layer core–shell structure, was synthesized successfully by two reaction steps of solvothermal reaction and in situ polymerization. The surface morphology, phase structure and chemical components of the composite have been characterized by a scanning electron microscope, X-ray diffraction and X-ray photoelectron spectroscope. The results suggest that the surface of CS is covered by NiFe2O4 completely and PPy wraps the obtained NiFe2O4/CS successfully. The conductivity and the saturation magnetization (Ms) of the resulting PPy/NiFe2O4/CS composites are 0.38 S/cm and 46 emu/g, respectively. The vector network analysis shows the composite performs better microwave absorbing ability than that of CS and NiFe2O4/CS. The maximum reflection loss of the composite with 1.97 mm coating thickness is −53 dB at 10.5 GHz and the bandwidth of reflection loss less than −10 dB is 3.4 GHz (8.9–12.3 GHz). This ternary composite with light weight, thin thickness and strong absorbing capacity can be an attractive candidate in the field of microwave absorption.

Co-contamination of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in soil is very common worldwide. In this study, free (FE) and immobilized (IE) Escherichia sp. on biochar solidified with alginate were used to reveal the effect of cadmium (Cd) on pyrene biodegradation in solution, spiked soil, and field co-contaminated soils. The results showed that when there was no coexisting Cd, the average removal rates of pyrene in the FE and IE treatments were 99.3% and 92.9%, respectively, in solution within 28 days, and 90.2% and 77.4%, respectively, in spiked soil incubated for 90 days. When the concentration of coexisting Cd was 1 mg L−1 and 50 mg L−1 in solution, negligible biodegradation of pyrene was observed for both FE and IE treatments. In spiked soils, the removal rate of pyrene for FE (88.7%) was significantly higher than that for IE (52.9%) when the content of coexisting Cd was 1 mg kg−1. However, there was negligible biodegradation of pyrene in both FE and IE treatments when the content of coexisting Cd was 50 mg kg−1. In field co-contaminated soil, the biodegradation of PAHs was negligible for all treatments. In comparison to FE, IE did not show superiority in bioremediating co-contaminated soil in terms of PAH removal in this study.

OBJECTIVE Our goal is to determine the prognostic value of serum N-terminal prohormone of brain natriuretic peptide (NT-proBNP), leukocytosis, and hyperglycemia in patients with severe hand, foot, and mouth disease (HFMD). DESIGN This is a prospective cohort study conducted from March 2011 through October 2012 at Hunan Children's Hospital. SETTING Hunan Children's Hospital, a large children's teaching hospital with 1,500-beds located in the Changsha region of Hunan Province in China. PATIENTS 295 children who were presented with clinical manifestation of severe HFMD, and required hospitalization. INTERVENTIONS Standard supportive treatment for HFMD as recommended by the national guidelines. MEASUREMENTS Admission blood samples were analyzed for NT-proBNP, leukocyte count, and serum glucose. Independent prognostic value of NT-proBNP for predicting mortality was evaluated using the Cox proportional hazard model adjusting for various covariates. MAIN RESULTS Area under the curve of receiver operating characteristic (AUROC) analysis suggested that a serum concentration of NT-proBNP concentration more than 1,500 pg/mL is an optimal cutoff point. Twenty-four patients (8.1%) had an NT-proBNP more than 1,500 pg/mL, and a 3-day mortality of 46% (11/24). Adjusted for tachycardia, tachypnea, hypertension, hyperglycemia, leukocytosis, and conscious disturbance on presentation, elevated NT-proBNP was associated with a 22.5-fold (95% confidence interval, 3.56-142.66) increased risk of 3-day mortality. We have further improved the specificity and AUROC values by the HFMD laboratory score, which combines NT-proBNP, leukocytosis, and hyperglycemia. CONCLUSIONS Routine admission surveillance for NT-proBNP is useful for identifying patients with HFMD at risk for mortality. Further studies are needed to determine whether early intervention in patients with highly elevated NT-proBNP can improve outcome.