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The stray current corrosion brings negative effects on the machining quality and accuracy in electrochemical micromachining (EMM) of micro hole, limiting the industrial application of EMM. This paper proposes the electrochemical micromachining of micro hole using micro drill with non-conductive mask on the machined surface. In this method, non-conductive mask was coated on the workpiece surface first. Then, the mask was drilled precisely by micro drill to expose the workpiece surface, which was a mask through-hole. Thirdly, on the location of this mask through-hole, the same micro drill was used as a cathode electrode to fabricate micro hole through EMM. Lastly, the redundant mask was removed through a chemical method without damaging the original surface of workpiece. The simulation results show that the mask coated on the workpiece surface can reduce the stray current significantly, thereby decreasing the stray corrosion effectively. The cyanoacrylate was chosen as an ideal mask material because of its excellent properties, such as low cost, easy operation, etc. Through the above method, micro hole with high quality and accuracy was fabricated successfully, demonstrating that using micro drill with non-conductive mask coated on the workpiece surface can not only effectively protect the workpiece surface from corrosion, but also improve the machining quality and accuracy of micro hole in EMM.

As the inner tube is excited from a rotation frequency at a separation distance, the inner tube will generate a reciprocating screwing motion. In this work, this coupling effect is investigated theoretically. The van der Waals force between two carbon nanotubes is expressed in a simple form of Fourier series so that the coupled nonlinear differential equations can be quickly solved. The proposed approach is thousands of times faster than the traditional method, which makes it possible to fit the coupling coefficients. As a result, expressions for the coefficients of the coupled equations are given. It is observed that a larger initial rotation frequency excitation will result in a higher dissipation rate of the axial oscillation, and vice versa.

E74 is a key transcription factor induced by 20E, which plays a broad role in many physiological events during insect growth and development, including vitellogenesis, organ remodeling and new tissue formation, programmed cell death and metamorphosis. However, whether it is involved in regulating insect chitin biosynthesis remains largely unclear. Here, the E74 gene was identified for the first time from Hyphantria cunea, a notorious defoliator of forestry. Thereafter, the role of HcE74 in regulating growth, development and chitin synthesis in H. cunea larvae was evaluated. Bioinformatics analysis showed that HcE74 shared the highest identity (95.53%) with E74A of Spodoptera litura, which belonged to Ets superfamily. The results of RNAi bioassay showed that the larval mortality on 6 d after HcE74 knockdown was up to 51.11 ± 6.94%. Meanwhile, a distinct developmental deformity phenotype was found when HcE74 was silenced. These results indicated that HcE74 plays an important role in the development and molting of H. cunea larvae. Moreover, HcE74 knockdown also significantly decreased the expression of four key genes related to chitin synthesis, including glucose-6-phosphate isomerase (HcG6PI), UDP-N-acetylglucosamine pyrophosphorylase (HcUAP), chitin synthetase A (HcCHSA), and chitin synthetase B (HcCHSB). As a result, the content of chitin in midgut and epidermis decreased by 0.54- and 0.08-fold, respectively. Taken together, these results demonstrated that HcE74 not only plays a critical role in the growth and molting of H. cunea larvae, but also probably participates in the transcriptional regulation of genes involved in chitin biosynthesis.

The isothermal constant strain rate compression test of Ti-10.2Mo-4.9Zr-5.5Sn alloy was carried out by Gleeble-3500 thermomechanical simulator. The hot deformation behavior at temperature of 670–820 °C and strain rate of 0.001–10s−1 was studied, and the activation energy of hot deformation was calculated. The results show that the flow stress of the alloy is more sensitive to the deformation temperature and strain rate, and is reduced by the increase of the deformation temperature and the decrease of the strain rate; the activation energy of the hot deformation of the alloy is higher than the self-diffusion activation energy of pure α titanium and pure β titanium alloy. According to the error calculation, the correlation coefficient and the average relative error of the constitutive model of Ti-10.2Mo-4.9Zr-5.5Sn alloy established by strain compensation are 0.9716 and 6.24%, and they own good precision. Based on the hot processing map of the Ti-10.2Mo-4.9Zr-5.5Sn alloy set up by the dynamic material model, instability zone's unstable form is mainly local flow and stable zone's deformation mechanism is mainly dynamic recovery and dynamic recrystallization through analyzing stable and unstable zones' microstructure; and it is found that the suitable deformation parameters of Ti-10.2Mo-4.9Zr-5.5Sn alloy are as follows: deformation temperature 670–700 °C, strain rate 0.001–0.003s−1, deformation temperature 790–820 °C, and strain rate 0.001–0.1s−1 through the processing map and microstructure observation.

Solar heating system has raised much attention due to the global energy shortage and environment pollution. The dynamic heat release performance of water tank (WT) with phase change materials (PCM) plays an important role in the operation of solar heating system, while seldom available literatures focused on this research topic. In this paper, an experimental system for heat release of the WT-PCM was established. The temperature variations of the water and the PCM during heat release of the WT-PCM and the traditional water tank were measured respectively, and their dynamic heat release performance were also analyzed based on the measured data. The results are as follows: the heat release of the WT-PCM can be divided into three phases: sensible heat before phase change, latent heat during phase change and sensible heat after phase change, and the water temperature will be temporarily heated after the sudden drop; the water supply temperature decline rate of both tanks will increase dramatically at the initial stage of heat release, when the PCM temperature is reduced to 50℃, the water supply decline rate of the WT-PCM is less than that of the traditional water tank, while when PCM is completely solidified, the water supply temperature decline rate of the WT-PCM is more than that of the traditional water tank. The heat release performance of the WT-PCM is much better than that of the traditional water tank. The research results can provide useful reference for engineering application of the WT-PCM.

Our previous studies had identified that both crude extracts and total alkaloid from Chelidonium majus exerted a significant antifeeding and larval lethality on Lymantria dispar. Moreover, sanguinarine, chelidonine, berberine hydrochloride and coptisine were the main alkaloid in C. majus exerting toxicity to L. dispar. In this paper, we evaluated the insecticidal and antifeeding activities of each alkaloid on the 3rd instar L. dispar larvae by bioassay. Meanwhile, the effects of alkaloids from C. majus on the activities and mRNA levels of three main digestive enzymes in L. dispar larvae were investigated. The results indicated that sanguinarine possessed the strongest insecticidal activity with a LD50 value of 4.963 μg/larva, and the coptisine showed little lethality to 3 rd instar L. dispar larvae among four alkaloids from C. majus. The insecticidal capacity of four alkaloids on 3rd instar L. dispar larvae was in the following decreasing order of sanguinarine > chelidonine > berberine hydrochloride > coptisine. Similarly, except coptisine, the other three alkaloids significantly reduced food intakes of third instar L. dispar larvae and suppressed activities of three digestive enzymes (α-amylase, lipase and total protease) simultaneously. Finally, qRT-PCR analysis revealed that the transcriptions of α-amylase, lipase and serine protease were affected by sanguinarine. Especially, at 48 h after treatment, the mRNA expressions of those digestive enzymes were significantly suppressed by sanguinarine. In conclusion, we suggested that alkaloids from C. majus induced antifeeding and larval lethality on L. dispar larvae by suppressing food intake and digestive enzymes in L. dispar. Our findings provide a novel insight into evaluating the antifeeding and insecticidal properties of C. majus, which afford a new strategy for integrated pest management programs as well.

The utilization of renewable biomass cellulose in treating pollution of heavy metal ions (HMIs) is one of overarching and appealing strategies, because it simultaneously satisfies sustainable development and resolves ever-increasing environmental issue. In this regard, the composite cellulose@Mg(OH)2 was prepared via a facile method and explored for its use as water treatment agent. It is demonstrated that the smaller and thinner hexagonal Mg(OH)2 flakes are constructed onto the cellulose substrate by self-assembling; two components are chemically coupled via hydrogen bonds and Mg-Oc (cellulose oxygen) dative bonds; what’s more, the coupling of cellulose with Mg(OH)2 (1 0 1) facet is much more preferential than with (0 0 1) facet. The resultant composite material shows remarkable HMI removal performance: large capacities of 734.9, 595.8 and 1473.1 mg g−1 for Cd2+, Cu2+ and Pb2+, respectively. Further assisted by good shaping property of the cellulose substrate, the composite is capable of being made into filter, which practically separates HMIs and purifies wastewater with high removal efficiency (99.99%) for Cd2+ even after operating for 110 days and potable water can be obtained. The mechanism is delineated with removal models and characterizations of HMI-recovered products.

The coupling between constructed wetlands and reservoir (CWs-R) afforded a novel ecosystem to improve the water quality and increase the emergency storage capacity of micro-polluted river drinking water source. In this study, spectroscopic characteristics of DOM in YL CWs-R ecosystem were first systematic studied based on a three-year field monitoring to investigate the chemical composition, sources and track the involved biogeochemical processes in the ecosystem. Three humic-like components (C1, C2, and C4, em >380 nm) and one protein-like component (C3, em 0.05), which implies that the biodegradation and production of protein-like component may balance each other in the CWs-R ecosystem. The ecological pond unit plays a major role in the removal and transformation of DOM, especially in summer, while wetland purification unit contributes little to DOM reduction. In addition, the decay of aquatic macrophytes in wetland purification unit and the risk of algal bloom in the ecological pond unit might become important autochthonous sources of DOM, especially in summer and autumn. These findings are critical for further understanding the transformation processes of DOM in large-scale CWs-R ecosystems, and could provide important implications to improve sustainable safety of drinking water sources.

The high-temperature deformation behavior of Zr-4 alloy was investigated by using isothermal compression tests performed on the Gleeble-3500 thermomechanical simulator in the range of temperatures 750–1000 °C with strain rates of 0.001–10s−1. Based on the above hot deformation conditions, the flow stresses are predicted efficiently and accurately by the PSO-BP artificial neural network model. The architecture of the network includes two hidden layers; the first hidden layer includes 15 neurons and the second 10 neurons. And the established model was further evaluated in terms of the correlation coefficient, absolute error, and average absolute relative error. The results show the measured and predicted flow stresses have a good agreement, which indicates that the PSO-BP neural network model can be widely used to analyze and predict the hot deformation behaviors at different experimental conditions. As revealed by micrographs, the phenomenon of spheroidization appears at a strain rate of 0.001s−1 below the transformation temperature of the β phase, while the lath-shaped microstructure is transformed into a microstructure that the grain is nearly equiaxed at the same condition mentioned above. However, the microstructure becomes uneven at a high strain rate above the transformation temperature of the β phase.

Background Malignant tracheoesophageal fistula (MTEF) is a devastating complication of esophageal cancer, lung cancer or other carcinoma with a shorter life-span and poor life quality. The aim of this study was to assess the effect of airway stent insertion on MTEF patients. Methods A total of 63 MTEF patients were included, 12 patients with lung cancer and 46 patients with esophageal cancers. Eight zones were proposed to classify various fistula locations. Airway stents were selected based on the various zones and fistula size. Results Airway stents were successfully inserted in all patients, and both airway and esophageal stents in 8 patients. Most fistula were located in locations II (18/63, 28.6%), III (22/63, 34.9%), then VII (9/63, 14.3%). The stents included 10 (15.9%) I shaped, 8 (12.7%) L shaped and 45 (71.4%) Y shaped. Different stents were placed based on different locations and sizes of fistulas. Overall, mean survival time was 163 days (2–270 days). Most symptoms relieved after stent insertion. Mean Karnofsky score jumped from 43.0 ± before stent placement to 66.7 ± after stent insertion ( P = 0.000). Complete closure was achieved in 45 patients (71.4%), and incomplete closure and leakage were found in 18 patients. Conclusions Airway stent insertion provides an effective approach to improve symptoms and quality of life. The choice of stent based on different fistula location and size may be a reasonable way in clinical practice.

Microalloy steels are generally Nb, V, or Nb, V, Ti composite microalloyed. Because of the high price of niobium and vanadium, the development of titanium microalloyed steels is a very interesting subject. In this study, steels with different Ti contents were refined and forged. Tensile tests were conducted and microstructures of samples were analyzed. Fine precipitates were observed using a transmission electron microscope. The results show that nanoscale Ti precipitates is the main factor enhancing strength of steels. The strength of steels increases with the Ti content. The optimum content range of titanium is between 0.04 and 0.10 wt.% while below 0.04 wt.% and higher than 0.10 wt.%, Ti has little effect on the strength of steels.