TDDFT calculations of the PETN's ultraviolet absorption spectrum under the electric field loading.

CONTEXT: The UV(ultraviolet) absorption spectrum of PETN under different electric field loading directions(X, Y, and Z) with the value of strength range from 0.001 a.u. to 0.006 a.u. was calculated with the TDDFT(Time-dependent density functional) in this work. With the increase of electric field strength, the absorbance of PETN in the ultraviolet band decreases. To explain the action mechanism of the electric field on PETN UV(ultraviolet) absorption spectrum, we analyzed and counted the contribution rate, oscillator strength, and vertical excitation energy of the main excitation process whose contribution rate to the UV absorption spectrum is greater than 10%. The contribution of PETN to the UV spectrum in all directions without an electric field was also listed to investigate the anisotropy of PETN in the excitation process under an electric field. The hole-electron analysis showed that the electric field will enhance the charge transfer characteristics in the excitation process of PETN. To investigate the anisotropy of the response under different electric field application directions, the contribution of the UV absorption spectrum in different directions was studied. METHODS: Optimization and TDDFT calculation were performed at the level of M06-2X/def2-TZVP and PBE0/def2-TZVP respectively, with Gaussian09 program. The hole-electron analysis and UV absorption spectrum plotting were performed with Multiwfn3.8.

Experimental and theoretical investigation into the response to shock wave for booster explosives JO9C, JH14, JH6, and insensitive RDX.

In order to reduce the vulnerability, the responses to shock waves for booster explosives JO9C, JH14, JH6, and insensitive RDX were evaluated using shock wave partition loading test. To explain the experimental results, molecular dynamics simulation, intermolecular interaction and bond dissociation energy (BDE), and shock initiation pressures were evaluated using the B3LYP, MP2 (full), and M06-2X methods with the 6-311 + + G(2df,2p) basis set. The order of the responsivity is JO9C > JH14 > JH6 > insensitive RDX. The binding energies follow the order of JH14* ≈ JO9C* < insensitive RDX* < JH6*. The interaction energies and BDEs are in RDX∙∙∙(CH3COOCa)+ > RDX∙∙∙CH3COOH > RDX∙∙∙CH2FCH2F. Thus, it can be inferred that for the RDX-based explosives, the stronger the binding energy, intermolecular interaction, and BDE are, the more insensitive the booster is, and thus, the larger energy has to be consumed to overcome the above three kinds of energies during the initiation process, leading to the smaller energy output and weaker response. However, it should be noted that it is mainly the density and the type of explosive that influence the depth of the dent produced on the steel witness block. The essence of the responses to shock waves is revealed by the reduced density gradient, atoms in molecules, and surface electrostatic potentials. HIGHLIGHTS: • Response of booster to shock wave was evaluated by shock wave partition loading test. • Responsivity to shock wave is explained by binding energy, intermolecular interaction, and BDE. • Shock initiation pressures were evaluated. • Essence of responses to shock wave is revealed by RDG, AIM and ESP.

Durability and corrosion behaviors of superhydrophobic amorphous coatings: a contrastive investigation.

Superhydrophobic surfaces can be derived from roughening hydrophobic materials. However, the superhydrophobic surfaces with various micro/nano morphologies present variations of chemical and mechanical durability, which limits their practical applications. Very little actually is known about comparing durability and corrosion resistance of concave and convex superhydrophobic surface structures systematically. In this paper, two kinds of superhydrophobic AlNiTi amorphous coatings with concave and convex surfaces were obtained by chemical etching and hydrothermal methods, respectively. Benefiting from nanoscale sheet structure, the convex superhydrophobic coating displays higher water-repellence (contact angle = 157.6°), better self-cleaning performance and corrosion resistance. The corrosion current density of the convex superhydrophobic surface is approximately one order of magnitude smaller than the concave superhydrophobic surface. Besides, the long-term chemical stability and mechanical durability of both superhydrophobic surfaces were also investigated. The formation and damage mechanisms of these two kinds of superhydrophobic surfaces were proposed. It is hoped that these investigations could provide clear guidance for the real-world applications of superhydrophobic amorphous coatings.

Zwitterionic Ferrocenes: An Approach for Redox Flow Battery (RFB) Catholytes.

Herein we present two new ferrocene compounds Fc3 and Fc4 with, respectively, propyl and butyl zwitterionic side chains. These compounds are highly soluble in water (0.66 M for Fc3 and 2.01 M for Fc4). When paired with anthraquinone-2,7-disulfonate as the anolyte, these zwitterionic ferrocenes exhibit excellent performance under neutral aqueous conditions. Voltage and energy efficiencies were ca. 88%, and the Coulombic efficiency was over 99% for both high-concentration redox flow batteries. We observed a difference in stability between the lengths of the zwitterionic chains, with Fc4 showing higher stability than Fc3, and the capacity decreased by ∼5% at the end of 20 cycles (∼1% per day). Density functional theory calculations revealed striking differences in the conformational properties between Fc3 and Fc4, with Fc4 retaining a linear structure of the side chain in solution, while Fc3 favored both linear and curved geometries.

Nondestructive Dimension Sorting by Soft Robotic Grippers Integrated with Triboelectric Sensor.

In smart logistics, traditional manual sorting and sorting systems based on rigid manipulators limit the warehousing development and damage the goods. Here, a nondestructive sorting method based on bionic soft fingers is proposed. This method is implemented by the soft robotic gripper (SRG) for grasping of the breakable objects, the triboelectric sensor (TES) for size sorting of the objects, and the signal processing module. In the fabrication of SRG, the silicon rubber is prepared by controlling the material synthesis process, and its Young's modulus is 600.91 kPa, which is comparable to the Young's modulus of skin tissue. Also, the maximum input pressure of SRG is 71.4 kPa. The TES has a linear relationship between pulse number and sliding displacement, and its resolution is 3 mm. It induces pulse signal sequences to quantify the SRG bending state and thus realize the size sorting of objects. Additionally, a nondestructive sorting system based on TES and SRG has been developed for fruit sorting (e.g., apples, oranges), enabling nondestructive grasping and accurate sorting. Its sorting range is 70-120 mm, and the sorting accuracy rate is up to 95%. This work also provides a way for the application of SRG and triboelectric sensors in the sorting field.

Self-Powered Sensing for Smart Agriculture by Electromagnetic-Triboelectric Hybrid Generator.

The lack of efficient, low-cost, distributed energy collection methods is a vital factor restricting the application of the Internet of Things (IoT) in smart agriculture. This paper proposes a method based on triboelectric nanogenerator and electromagnetic generator to realize self-powered IoT nodes and self-powered sensors at the same time. An energy harvesting and sensing device based on electromagnetic-triboelectric hybrid generator (ES-ETHG) is designed. The peak power of ES-ETHG is 32.4 mW, which can supply power to IoT nodes for a long time with power management circuits. In addition, ES-ETHG can critically measure wind speed and wind level within the range of 3-15 m/s, and accurately detect wind direction within 2 s. Furthermore, the self-powered distributed weather sensing system based on ES-ETHG is developed to realize the remote collection of wind speed, wind direction, temperature, and humidity. This work proposes a solution for developing self-powered IoT and sensor in the field of smart agriculture.

Highly Soluble Imidazolium Ferrocene Bis(sulfonate) Salts for Redox Flow Battery Applications.

Redox flow batteries (RFBs) are scalable devices that employ solution-based redox active components for scalable energy storage. To maximize energy density, new highly soluble catholytes and anolytes need to be synthesized and evaluated for their electrochemical performance. To that end, we synthesized a series of imidazolium ferrocene bis(sulfonate) salts as highly soluble catholytes for RFB applications. Six salts with differing alkyl chain lengths on the imidazolium cation were synthesized, characterized, and electrochemically analyzed. While aqueous solubility was significantly improved, the reactivity of the imidazolium cation and the increased viscosities of the salt solutions in water (which increase with increasing imidazolium chain length) limit the applicability of these materials to RFB design.

Formation and Properties of Superhydrophobic Al Coatings on Steel.

Thermal sprayed aluminum coatings are widely scalable to corrosion protection of the offshore steel structure. However, the corrosion rate of the Al coating increases considerably due to the severe marine environment. It has remained a challenge to improve the corrosion resistance and protective ability of Al coatings. The superhydrophobic surface provides a potential way to improve the corrosion resistance of metal materials. Hence, the development of superhydrophobic Al coatings with superior corrosion resistance is of great interest. In this work, the feasibility of the preparation of superhydrophobic Al coatings on a steel substrate was explored. First, Al coatings were prepared onto the steel substrate by the arc-spraying process, followed by ultrasonic etching with 0.1 M NaOH solution, and afterward passivated using 1% fluorosilanes. The effects of the etching time on morphology, contact angle, and corrosion resistance of the Al coatings were evaluated. The schematic model of the fluorosilane passivation process on the Al coating surface was provided. The micro/nanoscale surface structure of the low-surface-energy fluorosilanes promotes the wetting angle of 153.4° and a rolling angle to 6.6°, denoting the superhydrophobic properties. The superhydrophobic Al coating surface displays excellent self-cleaning performance due to its weak adhesion to water droplets. The corrosion current density of the superhydrophobic Al coating (1.36 × 10-8 A cm-2) is 2 orders of magnitude lower than that of the as-sprayed Al coating (1.18 × 10-6 A cm-2). Similarly, the charge-transfer resistance is found to be 12 times larger for the superhydrophobic Al coating and the corresponding corrosion inhibition efficiency reaches 98.9%. The superhydrophobic Al coating displays superior corrosion resistance and promising applications in a marine corrosion environment.

The Corrosion Resistance and Mechanism of AT13/Fe-Based Amorphous Composite Coatings.

Due to high strength, high wear resistance and high corrosion resistance, the amorphous metallic glasses were investigated widely. In the present study, the corrosion resistance of amorphous coating and composite coatings with various proportions of AT13 (Al2O3-13 wt.% TiO2) ceramic as additions in 3.5 wt.% NaCl solution were studied. The corrosion resistance was improved obviously as the addition of AT13, and when the content of AT13 was 15 wt.%, the composite coating had the lowest corrosion current density (1.75 × 10-6 A cm-2) and the highest corrosion potential (-411 mV), which was 5.14 × 10-5 A cm-2 and -580 mV for Fe-based metallic glassy coating, respectively. The corrosion mechanism was proposed according to the long-time immersion corrosion test.

Dynamic and Full-Time Acquisition Technology and Method of Ice Data of Yellow River.

Regarding the ice periods of the Yellow River, it is difficult to obtain ice data information. To effectively grasp the ice evolution process in the ice periods of the typical reach of the Yellow River, a fixed-point air-coupled radar remote monitoring device is proposed in this paper. The device is mainly composed of an air-coupled radar ice thickness measurement sensor, radar water level measurement sensor, temperature measurement sensor, high-definition infrared night vision instrument, remote switch control, telemetry communication machine, solar and wind power supply, lightning protection, and slewing arm steel tower. The integrated monitoring device can monitor ice thickness, water level, air temperature, ice surface temperature, and other related parameters in real time. At present, devices have obtained the ice change process of fixed points in ice periods from 2020 to 2021. Through a comparison with manual data, the mean error of the monitoring results of the water level and ice thickness was approximately 1 cm. The device realizes the real-time monitoring of ice thickness and water level change in the whole cycle at the fixed position. Through video monitoring, it can take pictures and videos regularly and realize the connection between the visual river and monitoring data. The research results provide a new model and new technology for hydrological monitoring in the ice periods of the Yellow River, which has broad application prospects.

Air-Flow-Driven Triboelectric Nanogenerators for Self-Powered Real-Time Respiratory Monitoring.

Respiration is one of the most important vital signs of humans, and respiratory monitoring plays an important role in physical health management. A low-cost and convenient real-time respiratory monitoring system is extremely desirable. In this work, we demonstrated an air-flow-driven triboelectric nanogenerator (TENG) for self-powered real-time respiratory monitoring by converting mechanical energy of human respiration into electric output signals. The operation of the TENG was based on the air-flow-driven vibration of a flexible nanostructured polytetrafluoroethylene (n-PTFE) thin film in an acrylic tube. This TENG can generate distinct real-time electric signals when exposed to the air flow from different breath behaviors. It was also found that the accumulative charge transferred in breath sensing corresponds well to the total volume of air exchanged during the respiration process. Based on this TENG device, an intelligent wireless respiratory monitoring and alert system was further developed, which used the TENG signal to directly trigger a wireless alarm or dial a cell phone to provide timely alerts in response to breath behavior changes. This research offers a promising solution for developing self-powered real-time respiratory monitoring devices.

[Analysis of follow-up and administration of HIV-infected Burmese in Dehong prefecture of Yunnan province].

OBJECTIVE: To compare follow-up and administration of HIV-infected local Chinese and Burmese in Dehong prefecture of Yunnan province, for scientific development of prevention and control measures. METHODS: 14 270 HIV-infected local Chinese and 5 436 HIV-infected Burmese reported from 1989 to December 31, 2013 in Dehong prefecture were recruited as the subjects of study, comparing the differences of follow-up and management, CD4⁺ T lymphocyte count tests and antiretroviral therapy (ART) between the two groups. RESULTS: The proportion of HIV-infected Burmese identified in Dehong prefecture was 27.6% (5 436/19 706) during 1989-2013. The number had been growing rapidly from 17.1% in 1989-2003, 12.4% in 2004 and 14.7% in 2005 to over 51.4% in 2012, hitting 59.4% in 2013 (trends χ² = 1 732.84, P < 0.000 1). The proportion of HIV-infected Burmese among case reports of various characteristics kept rising over the years. By the end of 2013, 8 095 HIV-infected local Dehong residents and 5 326 HIV-infected Burmese were still alive. 95.8% of them were under follow-up, 88.5% having CD4⁺ T lymphocyte count tests, and 78.3% under ART. Among the HIV-infected B urmese, only 19.2% of them were under follow-up, 13.0% having CD4⁺ T lymphocyte count tests, and 6.1% under ART, significantly lower than the local Dehong residents (P < 0.000 1). CONCLUSION: The proportion of follow-up and administration, CD4⁺ T lymphocyte count tests, and ART of HIV-infected Burmese was low in Dehong prefecture, Yunnan province, which called for more effective follow-up and administration measures.

[Investigation on mosquitoes and mosquito-borne viruses in Dehong prefecture, Yunnan province, 2007 and 2010].

OBJECTIVE: To investigate the distribution patterns of mosquito and mosquito-borne viruses in Dehong prefecture, Yunnan province, China. METHODS: Mosquito samples were collected using the mosquito traps from five counties of Dehong prefecture on July, 2007 and 2010. Mosquito were cell cultured for viral isolation, and positive isolates were identified using RT-PCR and sequence analysis. RESULTS: A total of 43 634 mosquito comprised of 29 species representing six genera were collected. Culex tritaeniorhynchus and Anopheles sinensis comprised 78.69% and 14.77% of the total. Six strains of viruses were isolated from the mosquito pools. RT-PCR and phylogenetic analysis revealed three strains from Cx. tritaeniorhynchus, identified as genotype I Japanese encephalitis virus (JEV). One strain was identified from Cx. tritaeniorhynchus, as Getah virus (GETV). Two strains isolated from Cx. tritaeniorhynchus and Anopheles vagus were identified as Culex pipiens pallens Densovirus (CppDNV). CONCLUSION: Cx. tritaeniorhynchus had been the major species of mosquito and mainly transmitting vector of mosquito-borne viruses in Dehong prefecture. Genotype I JEV, GETV and CppDNV were the vectors causing transmission of mosquito-borne diseases in this area. Data from phylogenetic analysis showed that these newly discovered isolates seemed to have had close relationship with those viruses previously circulating in Yunnan and other provinces of China.

Mosquitoes of Western Yunnan Province, China: seasonal abundance, diversity, and arbovirus associations.

OBJECTIVE: The western borderland between Yunnan Province, China, and Myanmar is characterized by a climate that facilitates year-round production of mosquitoes. Numerous mosquito-transmitted viruses, including Japanese encephalitis virus circulate in this area. This project was to describe seasonal patterns in mosquito species abundance and arbovirus activity in the mosquito populations. METHODS: Mosquitoes were collected in Mangshi and Ruili cities of Dehong Prefecture near the border of China and Burma in Yunnan Province, the Peoples Republic of China in 2010. We monitored mosquito species abundance for a 12-month period using ultraviolet light, carbon dioxide baited CDC light and gravid traps; and tested the captured mosquitoes for the presence of virus to evaluate mosquito-virus associations in rural/agricultural settings in the area. RESULTS: A total of 43 species of mosquitoes from seven genera were collected, including 15 Culex species, 15 Anopheles spp., four Aedes spp., three Armigeres spp., one Mimomyia spp., two Uranotaenia spp. and three Mansonia spp.. Species richness and diversity varied between Mangshi and Ruili. Culex tritaeniorhynchus, Culex quinquefasciatus, Anopheles sinensis and Anopheles peditaeniatus were the most abundant species in both sampling sites. Ultraviolet light traps collected more specimens than CDC light traps baited with dry ice, though both collected the same variety of mosquito species. The CDC gravid trap was the most effective trap for capture of Culex quinquefasciatus, a species underrepresented in light trap collections. A total of 26 virus strains were isolated, which included 13 strains of Japanese encephalitis virus, four strains of Getah virus, one strain of Oya virus, one strain from the orbivirus genus, and seven strains of Culex pipien pallens densovirus. CONCLUSIONS: The present study illustrates the value of monitoring mosquito populations and mosquito-transmitted viruses year-round in areas where the climate supports year-round adult mosquito activity.

[Epidemiological survey of suspected natural foci of schistosomiasis in Luxi City].

Three schistosomiasis patients pathologically diagnosed were detected in Luxi City, Yunnan Province, a non-endemic area of schistosomiasis. All the cases were hospitalized for serious intestinal diseases, and Schistosoma japonicum eggs were detected under their colonic mucosa. The 3 patients all denied they had contacted with infested water outside their resident place, and it was suggested that they might be infected in the local area.