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The histidine behavior plays a crucial role in the structural and aggregation properties of protein folding and misfolding. Understanding the histidine behavior at the edge of the protein structure is critical for finding ways to disrupt fibril elongation and growth, but this impact remains poorly understood. In the current study, we used molecular dynamics simulations to investigate the edge substitution effect of histidine protonation on the structural and aggregation properties. Our data showed that ΔG1contributed the most to binding affinity compared to ΔG2and ΔG3. The different protonation states at the edge chain significantly impacted the secondary structure properties of the edge chain. Specifically, we found that such protonation behavior significantly affected specific regions, particularly the N-terminus (G9-Q15) and C-terminus (K28-A30). Further analysis confirmed that H6, H13, and H14 were directly involved in H-bonding networks with the C1_H14//C2_H13 interchain interactions critical for maintaining the interchain stability. Furthermore, we confirmed that H6, H13, and H14 were directly involved in the loss of the carbon skeleton contact in the N-terminus. Our findings indicate that the edge condition is more susceptible to changes in structural properties than the middle condition. The current study is helpful for understanding the histidine behavior hypothesis in related misfolding diseases.

The main goal of this article is to discuss the expansion of click chemistry. A new catalyst composed of CuO nanoparticles embedded in Zn-MOF with the ligand 2,4,6-tris(4-carboxyphenoxy)-1,3,5-triazine (H3L) is presented. The incorporation of CuO nanoparticles into the Zn-MOF structure led to desirable morphology and catalytic properties. The designed catalyst was evaluated for its catalytic role in the multicomponent reaction and copper-catalyzed azide–alkyne cycloaddition (CuAAC) for preparation of triazole rings with 80–91% yield. The catalyst demonstrated an appealing architecture and exhibited robustness, high efficiency, and environmental friendliness. Characterization of the catalyst was performed using various techniques, including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopes (TEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, and X-ray diffraction (XRD). The results suggest that this novel catalyst has the potential to be a valuable tool in the development of new synthetic approaches for a wide range of applications.

Sonodynamic therapy (SDT) is a promising strategy to treat deep-seated bacterial infections with good tissue penetration and spatiotemporal controllability. However, the low ROS generation efficiency of current sonosensitizers limits the development of SDT. Herein, we report a porphyrin derivative, TAPyPP-2, the sonodynamic activity of which is enhanced with less oxygen dependence by tuning its molecular assembly behavior. TAPyPP-2 can spontaneously form an ultra-small nano-assembly with a diameter of 6 nm in water by conjugation with primary amine salt-decorated pyridinium viaπ–π staking. The ultra-small assembly behavior can lower the energy gap between singlet and triplet states to 0.01 eV and promote the separation of holes and electrons, which facilitates ROS generation under ultrasound irradiation, in particular type I ROS. The unique hydrophilic ratio and positive charges endow TAPyPP-2 with superior abilities to interact with Staphylococcus aureus, resulting in extremely high sonodynamic antibacterial activity. Therefore, TAPyPP-2 successfully kills Staphylococcus aureusbacteria in the enclosed cavity of synovial joint and achieves effective SDT of septic arthritis. This work is anticipated to motivate enormous interest in the development of efficient SDT.

Accurate and fast prediction of tool conditions is fundamental to improve the machining accuracy and consistency in smart machining systems. The current tool condition monitoring methods, i.e., physics-based and data-driven approaches, have either low prediction accuracy or model generalization. To solve the shortcomings and utilize the benefits of both sides, a novel physics-guided deep learning model is developed in this study. The physics of cutting mechanics and tool wear model is applied to guide the model construction and regulate the network learning process. The model first generates large labeled simulation dataset for the pretraining of the deep network, and solves the problem of labeled-data insufficiency for network training in practice. It then fine-tunes the model through the monitored signal to optimize the network weight and alleviate the deviation between the physical model and the actual machining process, which improves the physical consistency and generalization of the model. Additionally, with the introduction of attention mechanism to the deep residual network, discriminant features can be extracted to distinguish wear values and working conditions. The experimental results show that by learning the physics, the physics-guided deep network can accurately predict the tool wear even under limited training sets and varied working conditions, and it outperforms the original data-driven models and the physical models.

ABSTRACT This study presents the influence of coral sand powder (CSP) on the hydration and mechanical behaviours of Portland cement paste at the curing ages from 1 day to 90 [...]

ABSTRACT In order to explore the effects of limestone powder on the long-term performance of calcium sulphoaluminate (CSA) cement, the hydration process and microstructure development of CSA cement incorporated with [...]

Objectives. This article aims to prompt first-line workers to go beyond regular job roles and engage in more discretionary safety behavior–safety participation in the Chinese construction industry. The construction industry is a high-risk industry, and first-line workers are more likely to be exposed to workplace hazards. Once accidents happen, the negative consequences would come out. Therefore, employee voluntary safety behavior is focused on in this research. Methods. The present research framework examines the roles of safety leadership and safety management practices from the group and organizational perspectives in predicting the voluntary safety behavior (safety participation) of first-line workers in the Chinese construction industry through casual-chain mediators (safety climate and job satisfaction). In this study, partial least squares structural equation modeling (PLS-SEM) is adopted for data analysis and hypotheses testing. Results. After data analysis, the results show that safety leadership and safety management practices are significantly and positively associated with safety participation of first-line workers through safety climate and job satisfaction. Moreover, safety management practices have a more statistical effect on safety climate compared to safety leadership. Conclusions. These results provide some practical implications for facilitating the workers to conduct safety participation inthe construction industry.

ABSTRACT This work investigates the influence of synthetic C-S-H/polycarboxylate(PCE) nanocomposites (CPNs) on the hydration and properties of hydrated cement pastes. HPEG-PCE copolymers exhibiting side chain length of 45 ethylene oxide [...]

Calcium sulphoaluminate (CSA) cement is an environmentally friendly material and has its specific characteristics, including good resistance to ingress of external chlorides. To date, performance evolution and relevant mechanism of CSA cement-based materials during its service in chloride environment are still not clear, and needs a thorough study before its widely application in practice. This paper reviews the research progress on the chloride transport, chloride binding and corrosion behavior of steel in CSA cement under chloride environment. The crucial factors influencing the resistance of CSA cement-based materials to chloride attack are emphasized, such as water-to-binder ratio, molar ratio of gypsum to ye’elimite and use of supplementary cementitious materials. Meanwhile, future research directions on chloride related durability issues of CSA are recommended.

Molecular diameter is an essential molecule-size descriptor that is widely used to understand, e.g., the gas separation preference of a permeable membrane. In this contribution, we have proposed two new molecular diameters calculated respectively by the circumscribed-cylinder method (Dn′) and the group-separated method (Dn), and compared them with the already known kinetic diameter (Dk), averaged diameters (Dpa), and maximum diameters (Dpmand Dmm) in correlating with the penetration barriers of small gas molecules on a total of 14 porous carbon-based monolayer membranes (PCMMs). D1′and D2′give the best barrier–diameter correlations with average Pearson’s correlation coefficients of 0.91 and 0.90, which are markedly larger than those (0.77, 0.76, 0.60, 0.48, 0.33, and 0.32) for D1, D2, Dk, Dpa, Dpm, and Dmm. Our results manifest that the choice of vdW radii set does not drastically change the barrier–diameter correlation. Our newly defined D1′, D2′, D1, and D2, especially D1′and D2′, show universal applicability in predicting the relative permeability of small gas molecules on different PCMMs. The circumscribed-cylinder method proposed here is a facile approach that considers the molecule’s directionality and can be applicable to larger molecules. The excellent linear correlation between Dn′and gas penetration barrier implies that the computationally less demanding molecular diameter Dn′can be an alternative to the penetration barrier in diagnosing the gas separation preference of the PCMMs.

With the standardizations of 400GE and 400G completed or near completion, the attention is now refocused to next generation techniques with larger bit rates, i.e., 800G. We can see that current research commonly aims to short-reach or metro transmission for sharing key components with 400G, while ultra-long-haul transmission (typically ≥ 1500 km) based on 800G is still in unknown state. Moreover, all-optical networking with OXC and ROADM is being gradually deployed all around the world, which further increases transmission performance requirement. According to past progress, it is urgent for us to analyze and clarify the requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. This work provides the technological prospection and requirements of 800G transmission systems for ultra-long-haul all-optical backbone networks. Firstly, the field network status and basic technical requirements for 800G are analyzed. Our record real-time 10-λ × 800-Gb/s sub-carrier-multiplexing 95-GBd DP PCS-64QAM transmission over 2018-km G.654.E Fiber with pure backward distributed Raman amplification shows that reusing the components of current 400G technique is not the future direction. By numerically simulating the transmission performances of non-fully-loaded and fully-loaded DWDM scenarios, symbol rate higher than 180GBd, G.654.E, and optical bandwidth ≥12 THz are necessary.

ABSTRACTThe petroleum industry is a high-risk industry and operates under the social technical system. Therefore, the safety behavior of employees needs to be paid high attention. Thus, six dimensions of safety management practices are identified as independent variables to predict a special component of common safety behavior-mindful safety practices in the Chinese petroleum industry. High-reliability organization theory is adopted as the underpinning theory. A total 255 first-line workers from a Chinese petroleum company participated in this survey. The results reveal that safety training and safety communication and feedback are positively related to safety motivation. Moreover, workers’ involvement and safety promotion policy have direct and positive impacts on mindful safety practices. Further, safety motivation is found to play a mediating role in the prediction of mindful safety practices in the Chinese petroleum industry. These findings give new insights for petroleum companies into how to promote mindful safety practices in the workplace.

ABSTRACTPrevious studies have concentrated on the value of managerial leadership for safety behavior conduct by employees in the workplace. However, safety leadership styles concerning mindful safety practices have rarely been examined. The goal of this study is therefore to investigate the relationships between safety-specific leaderships (transformational and active transactional leadership) and the adoption of mindful safety practices among first-line workers mediated by safety climate in the Chinese petroleum industry. Data were obtained from first-line workers in two Chinese petroleum companies. PLS-SEM results show that transformational and active transactional leadership are positively related to safety climate, which in turn affects mindful safety practice adoption in the Chinese petroleum industry. The results of the current study indicate that transformational and active transactional leadership in a safety-specific view offer a comprehensive leadership model for mindful safety practices conduct in the Chinese petroleum industry.

The effects of two-stage aging on the microstructures, tensile properties and intergranular corrosion (IGC) sensitivity of Al-Mg-Si alloys were studied by tensile testing and IGC experiments and transmission electron microscope (TEM). The results show that the two-stage aging (180°C, 2h+160°C, 120h) can reduce the IGC sensitivity without decrease the tensile properties. The grain is distributed with high-density β′′ phases, and the grain boundary phases are spherical and intermittently distributed. The formation of the microstructure characteristic is due to the lower re-aging temperature, which results in a decline differences in the diffusion rate between the matrix and grain boundaries. As a result, the pre-precipitated phase can maintain a better strengthening effects due to the slower growth rate. The pre-precipitated phase of the grain boundary presents a spherical and intermittent distribution due to the fast coarsening speed.

The effects of welding wire composition on microstructure and mechanical properties of welded joint in Al-Mg-Si alloy were studied by electrochemical test, X-ray diffraction (XRD) analysis and metallographic analysis. The results show that the weld zone is composed of coarse columnar dendrites and fine equated grains. Recrystallized grains are observed in the fusion zone, and the microstructure in the heat affected zone is coarsened by welding heat. The hardness curve of welded joint is like W-shaped, the highest hardness point appears near the fusion zone, and the lowest hardness point is in the heat affected zone. The main second phases of welded joints are: matrix α-Al, Mg2Si, AlMnSi, elemental Si and SiO2. The addition of rare earth in welding wire can refine the grain in weld zone obviously, produce fine grain strengthening effect, and improve the electrochemical performance of weld.

Many researchers have contributed to the assembly of zeolitic nanosheets and nanocrystallites into three-dimensional (3D) networks as it can remarkably improve the catalytic and/or adsorptive performances of zeolites. However, the applications of these synthesized materials are seriously limited because of low hydrothermal stability. A highly interesting strategy, but a great challenge, is the alignment of well-crystallized zeolite crystals into desirable architectures. Here, well-crystallized silicalite-1 crystals are assembled like toy Lego bricks into one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) architectures, and the assembly mechanism is investigated by combining elaborate experiments, in situ spectroscopy, and theoretical calculations. A 1D architecture was formed by stacking crystals along the baxis with the assistance of ethanol that is selectively adsorbed on (100) and (001) crystal facets. Such adsorption increases the condensation energy barriers along aand caxes, but facilitates the condensation between (010) facets. The assembly of the crystals into well-arrayed 2D architectures is achieved using both ethanol and benzaldehyde because of their preferable adsorption on the (001) facet. When an amphiphilic copolymer (P123) was further added in the gel along with the substitution of ethanol by 1-propanol, a 3D network was fabricated by the agglomeration and self-pillaring of the 2D Lego bricks possibly with P123 aggregates as the substrate matrix. Excitingly, upon alignment of crystals into 2D architectures, the adsorptive selectivity of 1-butanol (2 wt %) to water of silicalite-1 increases by 45.3 times, while into 3D networks, the catalytic activity for the Beckmann rearrangement of cyclohexanone oxime elevates by 79% along with a great enhancement of catalytic stability.

The intrinsic origin of amyloid aggregation has been pursued as a new pathogenesis for Alzheimer's disease (AD). The aggregation mechanisms influenced by histidine tautomerism were previously investigated in Aβ40 and Aβ42 monomers. In the present study, we focus on the structural properties of Aβ40 heterodimer under the influence of histidine. The results of molecular dynamics simulation detected different aggregation trends were detected in different heterodimers formed by the εεε isomer and other isomers. In the (εεε:δδδ) dimer, the highest β‐sheet content was obtained in the δδδ chain, which is in agreement with our previous studies that δδδ monomer is the most easily formed β‐sheet secondary structure in the monomer. Further analysis confirmed that (εεε:δδδ) dimers more easily aggregate into fibrils in comparison with other heterodimers. This research will help in understanding the tautomeric effect on Aβ heterodimers, thereby helping to figure out the pathogenesis of AD. Histidine tautomerism is considered to be one of the most important factors of Aβ aggregation. In this regard, we performed molecular dynamics simulations to study the dimerization of Aβ under the histidine tautomerism effect. The present study will help to better understand the histidine tautomeric effect on the early stage of Aβ aggregation, so as to find better treatments for Alzheimer's disease.

Enzymatic microarchitectures with spatially controlled reactivity, engineered molecular sieving ability, favorable interior environment, and industrial productivity show great potential in synthetic protocellular systems and practical biotechnology, but their construction remains a significant challenge. Here, we proposed a Pickering emulsion interface-directed synthesis method to fabricate such a microreactor, in which a robust and defect-free MOF layer was grown around silica emulsifier stabilized droplet surfaces. The compartmentalized interior droplets can provide a biomimetic microenvironment to host free enzymes, while the outer MOF layer secludes active species from the surroundings and endows the microreactor with size-selective permeability. Impressively, the thus-designed enzymatic microreactor exhibited excellent size selectivity and long-term stability, as demonstrated by a 1000 h continuous-flow reaction, while affording completely equal enantioselectivities to the free enzyme counterpart. Moreover, the catalytic efficiency of such enzymatic microreactors was conveniently regulated through engineering of the type or thickness of the outer MOF layer or interior environments for the enzymes, highlighting their superior customized specialties. This study provides new opportunities in designing MOF-based artificial cellular microreactors for practical applications.

The identification of the non-noble metal constituted TaO cluster as a potential analogue to the noble metal Au is significant for the development of tailored materials. It leverages the superatom concept to engineer properties with precision. However, the impact of incrementally integrating TaO units on the electronic configurations and properties within larger TaO-based clusters remains to be elucidated. By employing the density functional theory calculations, the global minima and low-lying isomers of the TanOn(n= 2–5) clusters were determined, and their structural evolution was disclosed. In the cluster series, Ta5O5was found to possess the highest electron affinity (EA) with a value of 2.14 eV, based on which a dual external field (DEF) strategy was applied to regulate the electronic property of the cluster. Initially, the electron-withdrawing CO ligand was affixed to Ta5O5, followed by the application of an oriented external electric field (OEEF). The CO ligation was found to be able to enhance the Ta5O5cluster’s electron capture capability by adjusting its electron energy levels, with the EA of Ta5O5(CO)4peaking at 2.58 eV. Subsequently, the introduction of OEEF further elevated the EA of the CO-ligated cluster. Notably, OEEF, when applied along the +xaxis, was observed to sharply increase the EA to 3.26 eV, meeting the criteria for superhalogens. The enhancement of EA in response to OEEF intensity can be quantified as a functional relationship. This finding highlights the advantage of OEEF over conventional methods, demonstrating its capacity for precise and continuous modulation of cluster EAs. Consequently, this research has adeptly transformed tantalum oxide clusters into superhalogen structures, underscoring the effectiveness of the DEF strategy in augmenting cluster EAs and its promise as a viable tool for the creation of superhalogens.

Design and development of flexible and high-performance supercapacitors is deemed necessary for portable and wearable electronic devices. In this study, a flexible and high performance PPy/TiO2/Ti3C2TXnanocomposite film as a negative electrode was prepared by electrochemically deposition of PPy/TiO2on the carbon cloths (CC) as substrate. Then, the prepared PPy/TiO2nanocomposite film was dipped repeatedly into the few-layered Ti3C2TXnanosheet solution to electrode exhibits a high areal capacitance of 472.0 mF cm−2at a current density of 3.0 mA cm−2and outstanding cycling stability of 84 % capacitance retention after 10,000 cycles. Furthermore, an asymmetric supercapacitor was assembled by combining PPy/TiO2/Ti3C2TXas the negative electrode and acid-treatment carbon cloth (TCC) as the positive electrode to increase the potential window of the system. The device exhibited a remarkable specific capacitance of 191.4 mF cm−2at 1.0 mA cm−2an excellent energy density of 1.2 mWh cm−3at a power density of 23.1 mW cm−3, as well as excellent power density of 41.5 mW cm−3at 0.12 mWh cm−3, and the capacitance retention of 87 % after 13,000 cycles, indicating that the PPy/TiO2/Ti3C2TXnanocomposite film has great potential as an electrode for fabrication of asymmetric supercapacitor.

Pseudocapacitive asymmetric supercapacitors are promising candidates for achieving high energy density in flexible energy storage devices. However, seeking suitable positive electrode materials that are compatible with negative electrode materials remains a considerable challenge. In the current study, a pseudocapacitive Ti3C2TxMXene used as negative electrodes is rationally compatible with redox-type V2O5as positive electrodes, resulting in the assembly of an all-pseudocapacitive Ti3C2TxMXene//V2O5asymmetric flexible energy storage device. The solid-state asymmetric device can deliver an energy density of 8.33 mW h cm–3at a current density of 0.5 A g–1. Moreover, it can operate in an expanded voltage window of 1.5 V, with dominant surface-capacitive charge-storage mechanisms. Additionally, the device can power a yellow light-emitting diode for up to 7 s, indicating the potential of the device for use in practical applications. This study demonstrates the possibility of using other two-dimensional transition-metal carbide nanosheets for high-energy density flexible energy storage devices.

Indoleamine 2, 3-dioxygenase 1 (IDO1) is the only rate-limiting enzyme outside the liver that catalyzes the oxidation and cracking of indole rings in the tryptophan along the kynurenine pathway (KP). The overactivation of IDO1 is closely related to the pathogenesis of various human immune and neurological diseases. As an important target for the treatment of many human serious diseases, including malignant tumors, the development of IDO1 inhibitors is of great practical significance. In this work, the structure and function of IDO1 both are summarized from the aspects of the signal pathway, catalytic mechanism, structural biology, and so on. Moreover, the current development status of IDO1 inhibitors is also systematically reviewed, which provides assistance for anti-cancer drug design based on the structure of receptors.

The intrinsic photonic properties of liquid-exfoliated (LE) MoS2struggle extremely for the desired optical applications. Theoretical and experimental results briefly reveal that the broadband photonic absorption in LE MoS2samples is ascribed to a synergistic mechanism, originated from layer-modulated electronic bandgaps and quantum confinement effects of ultra-small nanodots. Size fractionation of LE MoS2is promoted with differential centrifugation, and narrowed size distributions of fractionated samples are identified. Tunable aggregation of LE MoS2alters the distributions of the vertical and lateral dimensions, exhibiting ratiometric changes on photonic performances. With the integration of immunoassays, semiconducting MoS2nano-probes with antibody modifications can linearly respond to specific targets, e.g.carcino-embryonic antigens, ranging from 5.0 to 180.0 ng mL−1, viaratiometric photonic absorption measurements. The nanostructured MoS2optical ratiometric strategy exhibits a high repeatability, simple operation, low cost, and label-free characteristics, offering an alternative platform for practical immunoassays.

ABSTRACTWith the objective to study the effect of viscous property on the mechanical behaviour of structured clays, a series of compression and consolidation-undrained shear tests in different loading rates, using oedometer and triaxial instruments respectively, were carried out on undisturbed samples of clays. The compression curves in different load incremental ratios shows that the load incremental ratio has an effect on structural yield stresses, while it has little influence on compression indices of clays. The stress–strain–pore pressure curves show that shear strength increases, while pore water pressure decreases with increasing shear strain rate, and the critical state stress ratio is constant in reasonable shear strain rate range. When the shear strain rate exceeds the boundary of shear strain rate, the pore water pressure drops sharply and the failure mode changes from plastic failure to brittle failure. The test results illustrate that loading rate has an effect on the structural yield stress and shear strength, while it has little influence on compression index and critical state stress ratio of structured clays.

A thorough interpretation on the mechanisms that control the degradation of the electrical performance of organic thin-film transistors (OTFTs) during exposure to ambient environments is still developing. This is particularly true for n-type OTFTs. By performing density functional theory calculations, we have proposed a different degradation pathway of perylene diimide in ambient air. Compared to the most common ambient oxidant, O3, though seldom considered, can easily react with >C═C< in the π-conjugated charge-transfer center forming stable ozonides, which could be the underlying cause for relevant device failures. It is noteworthy that external electric fields which are ubiquitous while often overlooked in electronic devices can either accelerate or hamper the degradation process depending on the field direction. This finding underlines that in a rigid device configuration where electrodes are largely fixed, the way the molecules align on the substrate is pivotal to their ambient stability. Among the tested substituents, cyanation at the periphery of the perylene core resists O3/O2attack and favors electron transport by lowering the internal reorganization energy. This work constitutes the first step on understanding the interplay of interfacial oxidations and molecular charge-transport properties toward modeling the bulk electrical performance.

Development of detection platforms having portable, easy-to-use, and cost-effective designs is essential for environmental monitoring as well as food safety inspection. Herein, we proposed a smartphone-based handheld sensing strategy integrated with nitrogen-doped carbon dots (NCDs) test strip by employing three-dimensional (3D) printing technology for visual detection of Hg2+. Using this handheld detection platform, the FL color of test strips varied from red to purple with the increase of Hg2+concentration. A great linear response between the R/B value and Hg2+concentration in the range of 0 μM− 125 μM was shown, with a detection limit of 0.024 μM. Further, the constructed platform was applied for quantitative detection of Hg2+in real water samples. Interestingly, as-prepared NCDs allowed the monitoring of Hg2+with the dual-signal ratiometric model. Finally, the NCDs were used to detect Hg2+in biological systems with satisfactory results. This work will contribute to the new strategy to design easy-to-use and user-friendly devices for on-site quantitation of targets.

To improve the simulation accuracy of the thermal characteristic of ball screw feed drive systems, a dynamic thermal-structure coupling model, which considered the effect of the thermal contact conductance (TCC) of the solid joint on the accuracy of simulation results, was proposed to conduct thermal characteristic analysis of ball screw feed drive systems. The predictive model for TCC was proposed based on the micro morphology description of rough surfaces and the contact load distribution of solid joints. Then, the dynamic thermal-structure model of the ball screw feed drive system was established. To validate the effectiveness of the dynamic thermal-structure coupling model, thermal characteristic experiments of the ball screw feed drive system were conducted under different feed rates. The results showed that the simulation accuracy of temperature field and axial thermal elongation can be improved from 65% to 87% and from 70% to 85%, respectively.

To improve the accuracy, generality and convergence of thermal error compensation model based on traditional neural networks, a genetic algorithm was proposed to optimize the number of the nodes in the hidden layer, the weights and the thresholds of the traditional neural network by considering the shortcomings of the traditional neural networks which converged slowly and was easy to fall into local minima. Subsequently, the grey cluster grouping and statistical correlation analysis were proposed to group temperature variables and select thermal sensitive points. Then, the thermal error models of the high-speed spindle system were proposed based on the back propagation and genetic algorithm–back propagation neural networks with practical thermal error sample data. Moreover, thermal error compensation equations of three directions and compensation strategy were presented, considering thermal elongation and radial tilt angles. Finally, the real-time thermal error compensation was implemented on the jig borer’s high-speed spindle system. The results showed that genetic algorithm–back propagation models showed its effectiveness in quickly solving the global minimum searching problem with perfect convergence and robustness under different working conditions. In addition, the spindle thermal error compensation method based on the genetic algorithm–back propagation neural network can improve the jig borer’s machining accuracy effectively. The results of thermal error compensation showed that the axial accuracy was improved by 85% after error compensation, and the axial maximum error decreased from 39 to 3.6 µm. Moreover, the X/Y-direction accuracy can reach up to 82% and 85%, respectively, which demonstrated the effectiveness of the proposed methodology of measuring, modeling and compensating.

High-speed spindles often suffer from degeneration in its machining accuracy caused by the uneven distribution of temperature field. In order to improve the machining accuracy of high-speed spindles, a three-dimensional (3D) finite element analysis (FEA) model, which considered the combined effect of thermal contact resistance (TCR) and the change in heat power and stiffness caused by thermal displacements of bearing components on the accuracy of simulation results, was proposed to conduct transient thermal-structure analysis of high-speed spindles. The predictive model for TCR was proposed based on the fractal theory to characterize the rough surface morphology with disorder, self-affinity and non-stationary random features. And a contact mechanics model was developed to consider the influence of asperities’ deformation on TCR. The thermal-structure model of bearing was proposed to calculate the heat power and stiffness based on the quasi-static mechanics analysis. The FEA model proposed in this paper was used to simulate the temperature field distribution and thermal deformations of the high-speed spindle system. Then thermal characteristic experiments were conducted to validate the effectiveness of this model. The results showed that the FEA model was much more accurate than the traditional model which ignored the above two important factors. The temperature field and thermal errors of the spindle system were analyzed.

The food additives sodium bisulfite, sodium hypochlorite, citric acid, and ammonium persulfate were evaluated for their effectiveness in degrading aflatoxin in samples of distillers wet grains (DWG) and condensed distillers solubles (CDS) obtained from an industrial ethanol plant. Aqueous food additive solutions, 0.5% by weight, were added to DWG or CDS at the level of 0.5 ml/g of sample, and the materials were heated at 90°C for 1 h. Sodium bisulfite was not effective in degrading aflatoxin in either DWG or CDS. Among the four food additives tested, sodium hypochlorite was the most effective. However, it bleached the substrate and left an off-odor. Citric acid and ammonium persulfate reduced aflatoxin levels by 31 to 51%. Citric acid is the most promising additive for degrading aflatoxin because it has been classified as generally recognized as safe by the U.S. Food and Drug Administration. Aflatoxin reduction was enhanced by increasing the citric acid addition level and prolonging the heating time. Reductions of 65 and 80% in DWG and CDS, respectively, were obtained by the addition of 2.5% (by weight) citric acid and heating at 90°C for 1 h. Aflatoxin levels in DWG and CDS were gradually reduced with prolonged heating at 90°C, even without the addition of food additives. Aflatoxin reductions of 53 and 73% were achieved in DWG and CDS as a result of heating at 90°C for 5 h.

Exploration of new methodologies to tune catalytic selectivity is a long-sought goal in catalytic community. In this work, oil–water interfaces of Pickering emulsions are developed to effectively regulate catalytic selectivity of hydrogenation reactions, which was achieved via a precise control of the spatial distribution of metal nanoparticles at the droplet interfaces. It was found that Pd nanoparticles located in the inner interfacial layer of Pickering droplets exhibited a significantly enhanced selectivity for p-chloroaniline (up to 99.6%) in the hydrogenation of p-chloronitrobenzene in comparison to those in the outer interfacial layer (63.6%) in pure water (68.5%) or in pure organic solvents (46.8%). Experimental and theoretical investigations indicated that such a remarkable interfacial microregion-dependent catalytic selectivity was attributed to the microenvironments of the coexistence of water and organic solvent at the droplet interfaces, which could provide unique interfacial hydrogen-bonding interactions and solvation effects so as to alter the adsorption patterns of p-chloronitrobenzene and p-chloroaniline on the Pd nanoparticles, thereby avoiding the unwanted contact of C–Cl bonds with the metal surfaces. Our strategy of precise spatial control of catalysts at liquid–liquid interfaces and the unprecedented interfacial effect reported here not only provide new insights into the liquid–liquid interfacial reactions but also open an avenue to boost catalytic selectivity.

Herein, polyaniline/8-hydroxyquinoline (PAn-HQ) composites with various monomer feed ratios were developed as novel and efficient electrode materials to remove heavy metal ions including Hg(II), Cd(II), Pb(II), Cu(II), Ni(II), and Zn(II) from water resources. Besides detailed structural, morphological, and thermal stability studies, electrochemical properties of fabricated composites were investigated. Compare with PAn with increasing HQ concentration in the initial feed ratio, more resistant, compact, and sticky structures were observed, as well as excellent mechanical and thermal stability of the composites. Due to significant features of the prepared composites, the considerable removal capacity of heavy metal ions has been achieved through electrodeposition technique. Optimum experimental conditions such as HQ concentration, electrodeposition time, ionic strength, pH, and metal ion concentration were considered. Based on our findings, using 0.06 M HQ concentration, remarkable heavy metal ion removal occurs in an aqueous solution with adjusted pH including 1.0 M KNO3and 50 mg L−1initial concentration of metal ion during 24 min electrodeposition. The desorption study by the eluting adsorbent in deionized water at time intervals and adjusted acidic pH values revealed that the initial removal capability of the PAn-HQ composites preserves even after 10 cycles of electrodeposition/desorption. Finally, as-prepared PAn-HQ composites were employed to remove heavy metal ions from a collected real sample from Caspian Sea. The modified PAn-HQ electrodes fabricated via a facile and manageable electrochemical procedure are believed to offer significant adsorption capacity in environmental remediation to remove heavy metal ions.

In this article, a comprehensive geometrical–mechanical–thermal predictive model is developed for thermal contact conductance between two flat metallic rough surfaces. The rough surface was characterized by Weierstrass–Mandelbrot fractal function. The micro-morphology was measured by laser microscope to identify the fractal parameters that were then applied to mechanical and thermal modeling. A new contact mechanics model was then proposed to calculate the contact parameters, and different contact scales between asperities and three modes of deformation, elastic, elastic–plastic and fully plastic, were taken into account. The normal contact pressure, which should be equal to the exterior load, was formulated as a function of the fractal parameters, the maximum contact area and the material physical properties of the given surface. Based on the contact mechanics model, first a single pair of contacting asperities was proposed and then multi-contacting asperities were combined to get total thermal contact conductance. The influences of contact load, surface roughness, asperity top radius and contact area as well as the temperature on the thermal contact conductance were investigated by using the proposed model. The investigation results showed that thermal contact conductance increases with the contact load and contact area. The larger the surface roughness, the smaller is the thermal contact conductance. Finally, the experiments were conducted to validate the effectiveness of the thermal contact conductance modeling. This geometrical–mechanical–thermal predictive model was compared with the two existing predictive models and a series of experimental data. The results showed good agreement, demonstrating the validity of the model and providing certainty for further study on the heat transfer between contact surfaces.

Bone remodeling is balanced by bone formation and bone resorption as well as by alterations in the quantities and functions of seed cells, leading to either the maintenance or deterioration of bone status. The existing evidence indicates that microRNAs (miRNAs), known as a family of short non-coding RNAs, are the key post-transcriptional repressors of gene expression, and growing numbers of novel miRNAs have been verified to play vital roles in the regulation of osteogenesis, osteoclastogenesis, and adipogenesis, revealing how they interact with signaling molecules to control these processes. This review summarizes the current knowledge of the roles of miRNAs in regulating bone remodeling as well as novel applications for miRNAs in biomaterials for therapeutic purposes.International Journal of Oral Science advance online publication, 24 July 2015; doi:10.1038/ijos.2015.22

The present error compensation technology of computer numerical control machine tools ignores radial thermal tilt angle errors of the spindle, while the thermal-induced offset is closely related to the tilt angle and the handle length. To solve this problem, three models of spindle thermal errors are proposed for the thermal yaw, pitch angles and elongation, and error compensation is performed based on the thermal tilt angles and cutting tool length. A five-point method was applied to measure the spindle thermal drifts at different speeds by eddy current sensors, which could effectively analyse the changes in the position-pose of the errors. Fuzzy clustering and correlation analysis were applied to group and optimise the temperature variables and select the variables sensitive to thermal errors in order to depress the multicollinearity of the temperature variables and improve the stability of the model. Finally, the thermal offset compensation was conducted in three directions. The results indicate that back propagation has a better capability for nonlinear fitting, but its generalisation is far less than that of time series. While the structure of multiple linear regression analysis is simple, its prediction accuracy is not satisfied. Time series adequately reflects the dynamic behaviours of the thermal error, and the prediction accuracy can reach 94%, with excellent robustness under different cutting conditions. The thermal error compensation equation that includes thermal tilt angles and cutting tool length is suitable for actual conditions and can accurately describe the space-pose of the thermal deformation and improve the machining accuracy.

A jig-boring machine equipped with a dual-drive servo system can operate with high speed and accuracy. However, different friction behaviours and asymmetrical preloads of the double drive structures as well as asynchronous control over the master-slave motors can make the machine produce tremendous heat, causing uneven temperature distributions in the feed system and eventually leading to thermal deformation that reduces the positional accuracy of machines. To investigate the effects of thermal behaviours on machining accuracy, the thermal–structure finite element method was employed to analyse the transient thermal deformation and temperature field of the machine at different feed rates, considering boundary conditions such as the convective heat transfer coefficient and heat generation by motors, bearings, and screws. Additionally, a synchronous acquisition system was developed to measure the thermal behaviours, and the transient changes in temperature and deformation were compared with simulated values. Consequently, a synthetic thermal model was established to make accurate predictions based on the analysis of relationships between thermal error and equilibrium time, coordinate position and screw temperature. Finally, thermal error compensation was performed using a feedback integration method. The experimental data indicate that the finite element method model can accurately predict temperature distributions and thermal errors. Moreover, thermal errors were compensated at 24.1 °C and 22.6 °C with a feed rate of 18 m/min, and machining accuracy was increased by 73% and 62%, respectively.

The machine tool equipped with the dual-drive servo feed system could realize high feed speed as well as sharp precision. Currently, there is no report about the thermal behaviors of the dual-drive machine, and the current research of the thermal characteristics of machines mainly focuses on steady simulation. To explore the influence of thermal characterizations on the precision of a jib boring machine assembled dual-drive feed system, the thermal equilibrium tests and the research on thermal-mechanical transient behaviors are carried out. A laser interferometer, infrared thermography and a temperature-displacement acquisition system are applied to measure the temperature distribution and thermal deformation at different feed speeds. Subsequently, the finite element method (FEM) is used to analyze the transient thermal behaviors of the boring machine. The complex boundary conditions, such as heat sources and convective heat transfer coefficient, are calculated. Finally, transient variances in temperatures and deformations are compared with the measured values, and the errors between the measurement and the simulation of the temperature and the thermal error are 2 °C and 2.5 μm, respectively. The researching results demonstrate that the FEM model can predict the thermal error and temperature distribution very well under specified operating condition. Moreover, the uneven temperature gradient is due to the asynchronous dual-drive structure that results in thermal deformation. Additionally, the positioning accuracy decreases as the measured point became further away from the motor, and the thermal error and equilibrium period both increase with feed speeds. The research proposes a systematical method to measure and simulate the boring machine transient thermal behaviors.

•A model based balancing system is proposed.•The method owns both low-cost and high-balancing-speed superiorities.•The working principle of the balancing circuits is analyzed.•The model based balancing current estimation has been proposed and analyzed.•The method is experimentally validated in different working scenarios.

In the aid of sinc sum function and matrix equation a new 2D window function is obtained. It is as simple as a 2D cosine window function. Comparison shows that the new 2D window function can provide much better 2D FIR filters than 2D Hamming window function. Maximum passband ripples are about 2.5-3.5 times smaller and maximum stopband ripples are about 1.5 times smaller with equal or very small different passband and stopband edge frequencies.

In order to search the pointing accuracy degradation and the wheel-rail contact of the National astronomical observatory 50m radio telescope, according to the actual wheel-rail structure and design indicators, the wheel rail contact problem with the finite element analysis based on non-Hertz rolling contact theory is analyzed. The results show that the maximum deformation should be less than 1 mm. Then the measurement scheme of rail horizontal error and deformation is formulated. The mean value of the rail horizontal error is 2.89mm, while the maximum rail horizontal error is 1.5mm. The rail maintenance scheme is put forward after the flaw detection which finds large areas of cracks at the rail junction and the welded joint. The measurement is taken after rail maintenance; the experimental data coincide with the simulation results and then verify the correctness of the wheel-rail contact model, also the solution scheme of rail cracks. The reason for the pointing accuracy degradation is verified finally, which also can provide an effective method for the wheel-rail design and maintenance of large radio telescope.

In present Chinese universities, a number of industrial design professionals have set up a mobile device UI design courses, but as other emerging professional development involves unprecedented areas covered by the mobile device UI design knowledge and interdisciplinary knowledge, this emerging curriculum in the door not only for students new field, there are also challenges for the school teacher, to explore ways and means for effective teaching in the course of this article from the point of view of building a learning situation, in order to effectively promote the improvement of teaching effectiveness.

•A novel liquid-immersed battery thermal management system was designed.•The No. 10 transformer oil with insulation and cooling properties is a suitable choice for the immersion cooling liquid.•The liquid-immersed battery thermal management system can significantly decrease the maximum temperature and temperature difference of the battery module.•Increasing the immersion depth and flow rate can effectively guarantee the battery operating under the optimum temperature range of 25 °C∼ 40 °C.•The maximum temperature and temperature difference of the optimal liquid-immersed cooling scheme can be controlled below 40 °C and 1.5 °C, respectively.

One dimensional dynamic performance model of submarine diesel exhaust deballasting system is developed. Cross section of outer shell of ballast tank is described as cylinder, one dimensional flow equations combined with webie combustion model and woschni heat transfer model are employed to describe diesels flow characteristic. Coupled effect between gas pressure in ballast tank and discharging performance of diesel is considered in the presenting model. Deballasting duration for one certain submarine model is calculated using the developed model, and the result agrees well with that obtained by using Chinese state code for submarine low pressure system design. For different cross section tank models as circular section model, parabolic section model and trapezoidal section model, dynamic performance of diesel exhaust deballasting system is studied using the validated model. Gas pressure in tank, dropping speed of tank water surface and draft of submarine are simulated, and the results show that little difference of deballasting duration is caused by changing tank cross section. The most stable deballasting process is achieved by using a circular section tank. Deballsting performance is also studied as tonnage of submarine and volume of ballast tank change and commonsense conclusions are obtained.

As the most significant performance, compliance of hydraulic system is defined as the capacity to accommodate the sudden change of the external load. Due to the different requirements of the compliant tasks, the existing method for mechanical systems cannot be used in the analysis and design of the hydraulic system. In this paper, the definition and expression of compliance of hydraulic system are proposed to evaluate the compliance of the hydraulic system operating under sudden change load. Because the unexpected geological conditions during excavation may exert sudden change load to the shield tunneling machine, the compliance theory has found a right application in the thrust hydraulic system. By analyzing the basic operating principle and the commonly used architectures of the thrust hydraulic system, a compliance based thrust hydraulic system design method is presented. Moreover, a tunneling case is investigated in the paper as an example to expound the validation of design procedure. In conclusion, the compliance of the hydraulic system can be served as an evaluation of the capability in conforming to the load impact, giving supports for the design of the thrust hydraulic system of shield tunneling machines.

SIGSO satellite is a special kind of geosynchronous orbit communications satellites. Its orbit height is the same as geostationary orbit, but its inclination varies periodically and annually, with variation in the range of 0 ° to 15 °. When communication master station uses large-diameter antenna tracking SIGSO satellites, only a fraction of 1 degree of the antenna beam width is relatively small along with its inclination becomes bigger. Then which kind of tracking mode should be selected to keep precisely pointing to the SIGSO satellite becomes a very important issue. This paper takes Apstar-1 satellite as an example to analyze SIGSO satellites motion characteristics. Pros and cons of a 16-meter antenna with Truss-step tracking Apstar-1 satellite were studied and actual measurement was carried out in Beijing. Finally, mono-pulse tracking and turntable antenna mount is recommended which lays a good foundation for the system optimization design.

CO2 solid adsorbent was prepared through impregnating acrylonitrile (AN) modified monoethanolamine (MEA) into structurally disordered mesoporous silica (M) pore channel. Its structure was characterized by X-ray diffraction characterization (XRD), N2 adsorption-desorption tests (BET), Transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR). The capacity of CO2 adsorption and desorption were measured and evaluated by comparison with MEA-impregnated material. The results showed that the capacity of M-MN-50 reached up to 125.8 mg·g-1 and could desorb completely at the temperature of 40 °C by vacuum with 2.6 KPa. The hybrid material exhibited satisfactory performance during 10 turnovers.

One dimensional dynamic model for submarine low pressure screw compressor deballasting system performance analysis is developed. Cross section of outer shell of ballast tank is described as cylinder, one dimensional flow equations combined with screw compressor performance model are employed to describe compressors flow characteristic. Coupled effect between gas pressure in ballast tank and discharging performance of screw compressor is considered in the presenting model as gas leakage during compressing process is taken into account. Deballasting duration for one certain submarine model is calculated using the developed model, and the result agrees well with that obtained by using Chinese state code for submarine low pressure system design. For different cross section tank models as circular section model, parabolic section model and trapezoidal section model, dynamic performance of screw compressor deballasting system is studied using the validated model. Gas pressure in tank, dropping speed of tank water surface and draft of submarine are simulated, and the results show that little difference of deballasting duration is caused by changing tank cross section. The most stable deballasting process is achieved by using a circular section tank. Deballsting performance is also studied as tonnage of submarine and volume of ballast tank change and commonsense conclusions are obtained.

It is a breakthrough exploratory area about sandstone-type uranium deposit of Bayanwula area in Erlian basin, Inner Mongolia, a detailed study of the form of occurrences . Ore-bearing horizon is the down cretaceous Saihan formation in Bayanwula area. Study on uranium occurrences which is significance for Uranium mining smelting.The host rocks are gray silt - fine sandstone, gray medium - fine sandstone, yellow medium - fine sandstone . The EPMA(electron probe microanalysis) results show that the uranium minerals are mainly pitchblende, coffinite, uranyl-carbonate, uranothorite, isomorphous uranium and uranium bearing phosphate. among which, the uranothorite and isomorphous uranium are of no industrial significance, uranium mineralization closely occurs with pyrite, ilmenite, quartz, feldspar, rare earth and organic matter.