The technique to suppress regenerative chatter is to regulate the spindle speed around the mean speed to disturb the regenerative mechanism. According to the technique, it builds a platform to collect, process the machine working information and output control instruction. On the platform, some advanced algorithms are applied to analyze and finish the control task.
This work mainly describes assessment of a photoelectrocatalytic method to determine chemical oxygen demand (COD) in refractory and low-concentration organics using a highly effective TiO2 nanotube array sensor in a thin-cell reactor. Twenty organic compounds, including recalcitrant organics from six categories, were used as model compounds to evaluate the accuracy of the method. The correlation between theoretical oxygen demand (ThCOD) and response COD was studied. The linear regression equation COD = α × ThCOD was obtained, where α is the slope of the regression equation representing the conformity between the actual COD value and the theoretical value. Results of the photoelectrochemical method used in the present paper show excellent conformity between ThOD and response COD for all model compounds, with α and correlation coefficient r values of 0.9903 and 0.9901, respectively. However, results using the standard dichromate method show poor conformity, with α and r values of only 0.8359 and 0.8213, respectively. Hence, we conclude that this photoelectrocatalytic method is superior to the dichromate method for determination of COD in refractory and low-concentration organics. The photoelectrocatalytic method possesses a detection limit of 0.5 mg L−1, while dichromate COD values lower than 20 mg L−1 could not accurately be detected, with the exception of sugars.
The developer should apply the idea of sustainable development in each stage and consider the cost comprehensively. In the decision-making phase, the developer should consider the social and economic benefits, demonstrate the feasibility of the project. At the design stage the design unit should make full use of the new technology and renewable resources to design the urban complex. In the implementation stage, the construction unit should control costs within budget and reduce the pollution to the environment. In the operational phase, the tenement and the users should utilize resources circularly and protect environment. Research on sustainable development on the city complex can not only play a positive role for building materials saving, energy saving, resources and the environment protection, but also can have a great impact on the economic benefits of the urban complex and can greatly reduce the operation cost of the late.
The transmission electron microscopy (TEM) specimen with thickness in nanometer scale is susceptible to hydrocarbon contamination and oxidation, and the specimen holder is also susceptible to contaminants, which would deteriorate the quality of TEM imaging and degrade the efficiency of TEM experiments. Conventional pretreatment devices often have limited functions and low practicability, which may cause problems for TEM specimens and holders. In this work, a multifunctional apparatus for plasma cleaning and storage of TEM specimens and specimen holders is developed based on the specific design of the vacuum joints. The apparatus includes a plasma cleaning system, holder storage station, and specimen storage station, which share the same vacuum system. The cleaning of hydrocarbon contaminants on the specimen and storage of the specimens and holders can be achieved simultaneously in this apparatus. TEM imaging and energy-dispersive X-ray spectroscopy (EDS) analyses of two treated specimens using the apparatus demonstrated that it could effectively remove hydrocarbon contaminants on the specimen. The holder storage station, used to preserve TEM holders in vacuum conditions, can also be modified as a specimen storage station by an appropriate design of the specimen storage platform, in which specimens are protected from water and contaminations. The designed apparatus not only robustly avoids damage to the ultrathin specimen and holders but also improves the working efficiency and reduces costs. These advantages could make our apparatus more appealing for the complement to the present commercial plasma cleaning and storage devices. HIGHLIGHTS: An apparatus for the pretreatment of transmission electron microscopy (TEM) specimens and specimen holders with three functions-plasma cleaning, holder storage, and specimen storage-was designed and fabricated. Using this single apparatus, the cleaning of hydrocarbon contaminants on the specimen and storage of the specimens and holders can be achieved simultaneously. The designed apparatus can not only robustly avoid damage to the ultrathin specimen and holders but also improve the working efficiency and reduce costs by adopting a single vacuum system. These advantages could make our apparatus more appealing for the complement to the present commercial plasma cleaning and storage devices.
Hydrogen peroxide (H2O2) in situ electrosynthesis by O2 reduction reaction is a promising alternative to the conventional Fenton treatment of refractory wastewater. However, O2 mass transfer limitation, cathodic catalyst selectivity, and electron transfer in O2 reduction remain major engineering obstacles. Here, we have proposed a systematic solution for efficient H2O2 generation and its electro-Fenton (EF) application for refractory organic degradation based on the fabrication of a novel ZrO2/CMK-3/PTFE cathode, in which polytetrafluoroethylene (PTFE) acted as a hydrophobic modifier to strengthen the O2 mass transfer, ZrO2 was adopted as a hydrophilic modifier to enhance the electron transfer of O2 reduction, and mesoporous carbon (CMK-3) was utilized as a catalyst substrate to provide catalytic active sites. Moreover, feasible mass transfer of O2 from the hydrophobic to the hydrophilic layer was designed to increase the contact between O2 and the reaction interface. The H2O2 yield of the ZrO2/CMK-3/PTFE cathode was significantly improved by approximately 7.56 times compared to that of the conventional gas diffusion cathode under the same conditions. The H2O2 generation rate and Faraday efficiency reached 125.98 mg·cm−2·h−1 (normalized to 5674.04 mmol·g−1·h−1 by catalyst loading) and 78.24% at −1.3 V versus standard hydrogen electrode (current density of −252 mA·cm−2), respectively. The high H2O2 yield ensured that sufficient ·OH was produced for excellent EF performance, resulting in a degradation efficiency of over 96% for refractory organics. This study offers a novel engineering solution for the efficient treatment of refractory wastewater using EF technology based on in situ high-yield H2O2 electrosynthesis.
The distribution and availability of microbes in the environment has an important effect on the composition of the gut microbiome of wild vertebrates. However, our current knowledge of gut-environmental interactions is based principally on data from the host bacterial microbiome, rather than on links that establish how and where hosts acquire their gut mycobiome. This complex interaction needs to be clarified. Here, we explored the relationship between the gut fungal communities of Tibetan macaques ( Macaca thibetana ) and the presence of environmental (plant and soil) fungi at two study sites using the fungal internal transcribed spacer (ITS) and next generation sequencing. Our findings demonstrate that the gut, plant and soil fungal communities in their natural habitat were distinct. We found that at both study sites, the core abundant taxa and ASVs (Amplicon Sequence Variants) of Tibetan macaques’ gut mycobiome were present in environmental samples (plant, soil or both). However, the majority of these fungi were characterized by a relatively low abundance in the environment. This pattern implies that the ecology of the gut may select for diverse but rare environmental fungi. Moreover, our data indicates that the gut mycobiome of Tibetan macaques was more similar to the mycobiome of their plant diet than that present in the soil. For example, we found three abundant ASVs ( Didymella rosea , Cercospora , and Cladosporium ) that were present in the gut and on plants, but not in the soil. Our results highlight a relationship between the gut mycobiome of wild primates and environmental fungi, with plants diets possibly contributing more to seeding the macaque’s gut mycobiome than soil fungi.
NC machine monitoring system is built based on the wireless data acquisition. All kinds of the complicated information can be collected, and the test server can process the information. Some important information can transmit by the network, and the client and web can browse them and feedback to the NC machine. The experiment was done on the system platforms, and basic functions were realized. It provides a new method that it can solve the key problem of the NC machine remote monitoring.
Seamounts are undersea mountains rising abruptly from the sea floor and interacting dynamically with underwater currents. They represent unique biological habitats with various microbial community structures. Certain seamount bacteria form conspicuous extracellular iron oxide structures, including encrusted stalks, flattened bifurcating tubes, and filamentous sheaths. To extend our knowledge of seamount ecosystems, we performed an integrated study on population structure and the occurrence of magnetotactic bacteria (MTB) that synthesize intracellular iron oxide nanocrystals in sediments of a seamount in the Mariana volcanic arc. We found Proteobacteria dominant at 13 of 14 stations, but ranked second in abundance to members of the phylum Firmicutes at the deep-water station located on a steep slope facing the Mariana-Yap Trench. Live MTB dwell in biogenic sediments from all 14 stations ranging in depth from 238 to 2,023 m. Some magnetotactic cocci possess the most complex flagellar apparatus yet reported; 19 flagella are arranged in a 3:4:5:4:3 array within a flagellar bundle. Phylogenetic analysis of 16S rRNA gene sequences identified 16 novel species of MTB specific to this seamount. Together the results obtained indicate that geographic properties of the seamount stations are important in shaping the bacterial community structure and the MTB composition.
Cardiovascular disease is the leading cause of human death worldwide. Drug thrombolysis, percutaneous coronary intervention, coronary artery bypass grafting and other methods are used to restore blood perfusion for coronary artery stenosis and blockage. The treatments listed prolong lifespan, however, rate of mortality ultimately remains the same. This is due to the irreversible damage sustained by myocardium, in which millions of heart cells are lost during myocardial infarction. The lack of pragmatic methods of myocardial restoration remains the greatest challenge for effective treatment. Exosomes are small extracellular vesicles (EVs) actively secreted by all cell types that act as effective transmitters of biological signals which contribute to both reparative and pathological processes within the heart. Exosomes have become the focus of many researchers as a novel drug delivery system due to the advantages of low toxicity, little immunogenicity and good permeability. In this review, we discuss the progress and challenges of EVs in myocardial repair, and review the recent development of extracellular vesicle-loading systems based on their unique nanostructures and physiological functions, as well as the application of engineering modifications in the diagnosis and treatment of myocardial repair.
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