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Inhibiting particles aggregation plays a crucial role in maintaining the stability of nanofluids. In this work, applying a rod electrode was developed to reduce particles aggregation and sedimentat...

The ambient air with the excessive moisture needs to be dehumidified for a comfortable environment using air conditioning. The planar membrane-based dehumidifier (PMD) is a potential technology to ...

Using the Stroh formalism, Green’s functions are obtained for phonon and phason dislocations and opening displacements on the interface of a one-dimensional hexagonal quasicrystal bi-material. The integro-differential equations governing the interfacial crack are then established, and the singularities of the phonon and phason displacements at the crack tip on the interface are analyzed. To eliminate the oscillating singularities, we represent the delta function in terms of the Gaussian distribution function in the Green’s functions and the integro-differential equations, which helps reduce these equations to the standard integral equations. Finally, a boundary element numerical approach is also proposed to solve the integral equation for the crack opening displacements, the asymptotic expressions of the extended intensity factors, and the energy release rate in terms of the crack opening displacements near the crack tip. In numerical examples, the effect of the Gaussian parameter on the numerical results is discussed, COMSOL software is used to validate the analytical solution, and the influence of the different phonon and phason loadings on the interfacial crack behaviors is further investigated.

Some surface coatings can protect metal surfaces and reduce scale deposition. Based on that, the biomimetic material polydopamine (PDA) can form a stable coating on many material surfaces; therefore, we propose an efficient one-step electroplating method for preparing anti-scale PDA coatings with high stability. The scale deposition test showed that the deposition weight of calcium carbonate on the coating is less than that of carbon steel after immersing in a supersaturated solution of calcium carbonate for 12 h at 70 °C and 90 °C, with a coating scale-inhibition efficiency of 55.02% and 66.96%, respectively. By using molecular dynamics simulation, it was found that water adsorption layers exist near the metal’s surface, and the existence of water adsorption layers on the hydrophilic surface is the main reason for the initial deposition of calcium carbonate. The interaction energy between the PDA molecular layer and water is weaker (−5.69 eV) for the surface with the PDA coating, and there is no dense water adsorption layer on the coating, which leads to the low probability of calcium carbonate adsorption on the PDA coating surface. Therefore, PDA coating can inhibit the deposition of calcium carbonate on the surface.

DNA recombination repair systems are essential for organisms to maintain genomic stability. In recent years, we have improved our understanding of the mechanisms of RecBCD/AddAB family-mediated DNA double-strand break repair. In E. coli, it is RecBCD that plays a central role, and in Firmicute Bacillus subtilis it is the AddAB complex that functions. However, there are open questions about the mechanism of DNA repair in bacteria. For example, how bacteria containing crossover hotspot instigator (Chi) sites regulate the activity of proteins. In addition, we still do not know the exact process by which the RecB nuclease or AddA nuclease structural domains load RecA onto DNA. We also know little about the mechanism of DNA repair in the industrially important production bacterium Corynebacterium glutamicum (C. glutamicum). Therefore, exploring DNA repair mechanisms in bacteria may not only deepen our understanding of the DNA repair process in this species but also guide us in the targeted treatment of diseases associated with recombination defects, such as cancer. In this paper, we firstly review the classical proteins RecBCD and AddAB involved in DNA recombination repair, secondly focus on the novel helical nuclease AdnAB found in the genus Mycobacterium.

Sodium carboxymethyl cellulose (SCMC) is one of the most promising scale inhibitors. In this study, the performance of SCMC in inhibiting the deposition of calcium carbonate on heat transfer surface at the temperatures ranging from 293 to 343 K was investigated by experiments, and the interaction between SCMC and calcite in the solution was explored by molecular dynamics simulation. The experimental results showed that the fouling resistance substantially decreases by adding the SCMC. The scale inhibition efficiency increases with the solution temperature, and the highest scale inhibition efficiency at 99.8% at 343 K. The simulated results showed that with the increase of the solution temperature, both the binding energy between SCMC and calcite plane and the probability of SCMC binding with calcium ions increase, which can effectively prevent the growth of calcium carbonate fouling on the heat transfer surface. Therefore, our computational results agree with the anti-scaling experimental phenomena.

In this work, molecular dynamics simulation has been applied to investigate the influence of external electric field on the evaporation of the aqueous nano-film. The evaporation of the aqueous nano-film with 2240 water molecules and 50 NaCl on a gold (1 0 0) surface is analyzed at the electric fields with various intensities (0, 0.05, 0.1, 0.2 and 0.3 V nm−1) and directions. The predictions show that the evaporation of aqueous film is remarkably enhanced when the electric field Ex = 0.2 or 0.3 V nm−1 is parallel to the aqueous film surface. It is also noted that free ions in the aqueous film are accelerated under the action of the higher Ex and water molecules in the hydration shell move together with the ions due to the hydration effect. As a result, the interaction between water molecules decreases, which is responsible for increasing the evaporation of the aqueous film under the action of the higher Ex. While applying the electric field Ey = ±0.3 V nm−1 perpendicular to the aqueous film, ions cannot be in accelerated motion due to the existence of a solid-liquid interface and a liquid-gas surface in y-direction. Therefore, the evaporation enhancement is much lower than that of the aqueous film under the action of the Ex.

Objective: Neuropilin-1 has been reported to be a valuable diagnostic biomarker in patients with cervical intraepithelial neoplasia (CIN) and early cervical cancer. The aim of this study was to investigate the association between Neuropilin-1 and the prognosis of cervical cancer in Henan Chinese population. Methods: Tissues were collected in The Third Affiliated Hospital of Zhengzhou University between 2010 and 2012, determining the level and expression of Neuropilin-1 in different cervical lesions by immunohistochemistry. The cell proliferation assay, wound-healing assays and Transwell assay were performed to explore the ability of proliferation, migration and invasion for Hela and Caski cells after NRP-1 was knocked down by shRNA transfection. Western blotting was performed to investigate the role of NRP-1 in endothelial-to-mesenchymal transition (EndMT). Tumor xenografts model was used to evaluate the effect of NRP-1 on the tumor growth. Results: The expression of NRP-1 was upregulated in the tumor tissues compared with the CIN and normal tissues (P

Numerous studies have speculated calcium carbonate (CaCO3) nucleation induced by pre-nucleation clusters (PNCs) aggregation. However, it is challenging for experiments to directly obtain the relationship between PNCs aggregation and nucleation. Herein, we employ molecular dynamics simulations to explore the variation during PNCs aggregation, which can describe the beginning stage of CaCO3 nucleation induced by PNCs aggregation in supersaturated solutions. The results reveal that the formation of CaCO3 nucleus consists of PNCs spontaneous growth, PNCs solubility equilibrium, and aggregation of PNCs inducing nucleation. The PNCs aggregation, accompanied by the variation in the configuration and stability of CaCO3 aggregate, breaks the solubility equilibrium of PNCs and creates conditions for the formation of the more stable nucleus. Besides, the CaCO3 nucleus with the higher coordination number and the lower hydration number form when decreasing the CaCO3 concentration or increasing the temperature. This work not only sheds light on the formation of the CaCO3 nucleus but also contributes to the explanation for CaCO3 polymorphism.

We investigate the solar modulation effect with the long time cosmic ray proton and helium spectrum measured by AMS-02 on the time scale of a Bartels rotation (27 days) between May 2011 and May 2017. The time-span covers the negative heliospheric magnetic field polarity cycle, the polarity reversal period and the positive polarity cycle. The unprecedented accuracy of AMS-02 observation data provide a good opportunity to improve the understanding of the time dependent solar modulation effect. In this work, a two-dimensional solar modulation model is used to compute the propagation of cosmic rays in the heliosphere. Some important ingredients of the model which reflect the global heliospherical environment are taken from the observations. The propagation equation is numerically solved with the pubic Solarprop code. We find that the drift effect is suppressed during the high solar activity period but nearly recovered in the first half of 2017. The time-dependent rigidity dependence of the mean free path is critical to reproduce the observations between August 2012 and October 2015., 23 pages, 3 tables, 8 figures

Interfacial nanolayer acting as a bridge linking a bulk solid phase and a bulk liquid phase has a crucial impact on the heat transfer from the solid to the liquid. In this work, we proposed a promising method to enhance the heat transfer between a Cu surface and liquid water by applying surface charges to the surface, which was expected to change the structure of the interfacial nanolayer. We employed molecular dynamics simulations to verify the effectiveness of the method. Our simulations showed that applying surface charges led to an orientational alignment of water molecules, reducing the spacing between the solid surface and the interfacial nanolayer and increasing the number of water molecules located at the interface nanolayer. Meanwhile, the presence of surface charges also improves the mismatch of vibrational density of states between solid atoms and water molecules. As a results, the heat transfer was enhanced as compared with that without surface charges and the enhancement becomes more remarkeble when applying more surface charges to the Cu surface.

BACKGROUND The aim of this study was to investigate the efficacy and safety of chemotherapy (CT) combined with stereotactic radiotherapy (SRT) in the treatment of nasopharyngeal carcinoma (NPC). MATERIAL AND METHODS A total of 329 NPC patients without any previous treatment were included in this study between January 2009 and November 2013. These patients were divided into three groups: CT group (n=114), SRT group (n=109), and CT + SRT group (n=106). Contrast-enhanced nasopharyngeal computed tomography (CT)/magnetic resonance (MR) scan was performed on the third month after treatment. Short-term efficacy was evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST). Toxicity was graded according to the Acute Radiation Morbidity Scoring Criteria (RTOG) and the World Health Organization (WHO) toxicity grading scale. Overall survival (OS), progression free survival (PFS), and incidence rate of acute toxicity (grade ≥3) were calculated after a 24 month follow-up. RESULTS Total response rate of all patients was 85.41%. Compared with the CT group and the SRT group, the CT + SRT group showed a substantially improved efficacy in NPC treatment. The incidence rate of the acute toxicity in the CT + SRT group was slightly higher than in the CT group and the SRT group, but the difference was not statistically significant. No treatment-related deaths were observed. The CT + SRT group had the highest two-year OS and PFS, followed by the CT group and the SRT group. CONCLUSIONS It was shown that NPC patients treated with CT + SRT had better short- and long-term efficacy than those treated with CT or SRT alone.

Rapid boiling of liquid film appears on solid surfaces with ultrahigh temperatures or heat fluxes, where a vapor layer is rapidly formed between the liquid film and the surface, leading to the film detachment from the surface and hence significantly reducing the heat transfer rate. In this work, a new idea, solid surface is charged with surface charges, is proposed to suppress the formation of vapor layer and prevent the liquid film detachment. To examine the effectiveness of the idea, the boiling behaviors of water films on gold (1 0 0) surfaces with various wettability conditions as well as with or without surface charges are investigated by molecular dynamics simulations. The results show that the electric field induced by the surface charges leads to an increased attractive interaction between the water film and the gold surface. Meanwhile, it is very interesting that a cone-shaped liquid column moves upward from the free surface of the water film due to the directional arrangement of water molecules along the electric field direction, which helps the nucleation bubble to break through the water film. Thus, the formation of vapor layer is suppressed and the water film detachment is never observed during the whole phase-change process of water film. The results also reveal that the electric field significantly increases the collision rate between water molecules and gold atoms, and hence enhances heat transfer from the gold surface to the water film.

In electric dehydration of crude oil, electrocoalescence of water droplets can be remarkably enhanced by increasing electric field strength, which promotes the settling separation of water droplets. However, non-coalescence of droplets occurs when the electric strength is higher than a critical value (Ec). Smaller daughter droplets will be ejected from the coalescing droplet in the process of the non-coalescence, which is undesirable for separation of droplets from crude oil. This work simulates the electrocoalescence of two identical droplets with dissolved KCl via molecular dynamics method. The results show that the value of Ec decreases with the increase of the droplet radius, this is because daughter droplets can be ejected more easily from the coalescing droplet with a larger radius due to stronger electric field force and smaller interfacial force. With the same initial centroid distances, the attractive energy between two larger droplets is stronger when an electric field is applied, and hence the two droplets migrate towards one another faster. However, the merging rate of the coalescing droplet is higher after two smaller droplets come into contact. In addition, it is also found that the daughter droplet with dissolved K+ is more easily ejected from the coalescing droplet during the non-coalescence, as compared to the daughter droplet with dissolved Cl−.

Fouling via the deposition of calcium carbonate (CaCO3) on heat transfer surface reduces the heat transfer efficiency and compromises the stable operation of the heat exchanger. Sodium carboxymethyl cellulose (SCMC) as a fouling inhibitor effectively prevents the growth of CaCO3. In this work, the fouling characteristics of a heat transfer surface by CaCO3 with the SCMC inhibitor were studied experimentally; the effects of the SCMC concentration, inlet temperature of the solution, mass flow, SCMC degree of substitution, and SCMC viscosity on fouling inhibition were investigated. Moreover, the asymptotic fouling thermal resistance and fouling inhibition efficiency were analyzed by varying the operation conditions and the physical properties of SCMC. The results show that the fouling thermal resistance decreases with increasing SCMC concentration, degree of substitution, and solution temperature, and increases with increasing mass flow of the solution. However, the effects of the SCMC viscosity varying from 600 mpa⋅s to 15000 mpa⋅s on fouling thermal resistance were observed to be negligible. Additionally, there was significant variation of the CaCO3 fouling morphology with a change from calcite particle to an irregular sphere after the addition of inhibitor.

In the presence of electric field induced by either constant or pulsed direct current (DC), a critical electric strength (Ec) exists for the transition from full coalescence to partial coalescence of adjacent charged droplets. In this study, the electro-coalescence behaviors of two charged droplets under constant and pulsed DC electric fields are studied via molecular dynamics simulations. The results show that the two droplets experience an attractive force when the constant DC electric field is applied, which causes an accelerated approach from one another before contact. However, under the pulsed DC electric field, the approach velocities of the two droplets accelerate within the pulse duration, while remain approximately constant during the pulse interval. Thus, the value of Ec for full coalescence and partial coalescence of the two droplets under the pulsed DC electric field becomes larger as compared with the constant DC electric field, which significantly reduces the time required for bringing the two droplets into contact. Hence, higher electro-coalescence efficiency is achieved. Furthermore, for a given pulse period, Ec is inversely proportional to the pulse duration; for a given duty ratio, Ec reduces with the increase in the pulse period.

In this study, we report a simple and facile method to fabricate an antibacterial composite coating by combining polydopamine (PDA), chitosan (CS) and silver nanoparticles (AgNPs) on urinary catheter and titanium (Ti) surfaces. The preparation consists of a co-deposition of PDA and CS in acid solution and subsequently immersion into silver nitrate (AgNO3) solution. This approach allows the antibacterial PDA/CS/AgNPs coating to be prepared for several hours by the simple immersion process under friendly conditions, and the surface morphology for coated catheters illustrated that CS plays a key role in improvement of the coating smoothness. The antibacterial tests against S. aureus were performed on the measurements of the inhibition halo and adhered bacterial numbers. The results showed that the PDA/CS/AgNPs-coated catheter has long-lasting stability for more than 30 days and antibacterial activity against S. aureus, and the antiadhesion rates of PDA/CS/AgNPs-coated Ti surface are 91 % and 85 % for live and dead bacteria, respectively. The PDA/CS/AgNPs coating based on the simple immersion has great potential in practical application for antibacterial urinary catheters and other biomedical devices.

When an electric field with various strengths is applied to two adjacent conducting droplets, the droplets may completely coalesce, partially coalesce, or bounce off one another. To reveal an atom-scale mechanism of coalescence or non-coalescence, dynamic behaviors of two conducting nanodroplets at a homogeneous electric field are studied via molecular dynamics simulations in this work. The results show that there is a critical field strength and a critical cone angle above which the two droplets partially coalesce or bounce off. Charge transfer between the two droplets is observed when the droplets are brought into contact. The partial coalescence and the bounce-off of the two droplets at strong field strengths are found to be due to the high charge transfer rate, which leads to the breakup of the coalescing droplet at different locations.

The present work employed a molecular dynamics method to investigate the effect of NaCl concentration on the deformation, breakup, and evaporation characteristics of bio-nanodroplets under a strong electric field. It aims to reveal the size control mechanism for a nanoparticle produced by electrospray deposition. The results show that when the droplet dissolves NaCl, it is elongated to be a longer “spindle” by the electric field force, compared to the droplet without NaCl, and several small clusters are ejected from two tips of the spindle due to the hydration effect of Na+ and Cl−. In addition, the formation of ion pairs is observed when the droplet dissolves NaCl. The NaCl concentration affects the hydration degree and the formation of ion pairs significantly, which leads to different spindle lengths and number of clusters. The longer spindle and the larger cluster number could enlarge the free surface area and remarkably accelerate evaporation. Fabrication of smaller bio-nanoparticle requires both a fa...

The study investigated the ability of ataxia-telangiectasia mutated (ATM)/Rad3-related (ATR) signaling pathway to influence the proliferation, apoptosis, and radiosensitivity of nasopharyngeal carcinoma (NPC) cells.NPC tissues and corresponding adjacent normal tissues were collected from 143 NPC patients. The NPC CNE2 cells were assigned into a control group, X-ray group, CGK-733 group, and X-ray+CGK-733 group. The mRNA levels of ATM and ATR were evaluated using quantitative real-time polymerase chain reaction (qRT-PCR) and the protein levels of ATM and ATR using western blotting. The positive expression of ATM and ATR in tissues and nude mouse tumor tissues was determined by immunohistochemistry. Cell proliferation, migration, invasion, and apoptosis rates were analyzed by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay, scratch test, transwell assay, and flow cytometry, respectively. A nude mouse model of NPC was established to observe tumor volume and growth.The mRNA levels of ATR and ATM and the expression of ATR and ATM protein in NPC tissues were significantly higher than those in adjacent normal tissues. The colony formation assay showed that the colony-forming rate decreased, showing radiation dose-dependent and CGK-733 concentration-dependent manners. Expression of ATM, ATR, Chk1, and Chk2 was evidently increased in the X-ray, CGK-733, and X-ray+CGK-733groups compared with the control group, and the aforementioned expression was highest in the X-ray+CGK-733 group among the four groups. The cell proliferation, invasion, and migration were decreased, tumor volume decreased and cell apoptosis increased in the X-ray, CGK-733, and X-ray+CGK-733 groups compared with the control group; the X-ray+CGK-733 group exhibited lowest cell proliferation, invasion and migration, smallest tumor volume, and highest cell apoptosis among the four groups.Inhibition of ATM/ATR signaling pathway reduces proliferation and enhances apoptosis and radiosensitivity of NPC cells.

An innovative process step-feed Anaerobic-multiple Anoxic/Oxic-Membrane Bioreactor [An-M(A/O)-MBR] was developed for biological phosphorus and nitrogen removal from synthetic domestic wastewater. This process was composed of an anaerobic reactor, a multiple phases of aerobic and anoxic zones (multiple A/O zone) in sequence followed by a continuous aerated MBR. Performance of the laboratory-scale system was investigated at different organic compounds in the influent. The results showed that, under the conditions imposed, although the Chemical Oxygen Demand (COD) concentration fluctuated in the range of 120–1,200 mg/L, high performance on COD removal was achieved in the system and more than 95% removal efficiency was obtained throughout the operation, the COD concentrations in the effluent were lower than 50 mg/L throughout the operation. However, COD levels in the influent had great influence on nitrogen and phosphorus removal. When COD level was low (120–200 mg/L), poor performance of nitrogen and...

The novel Schiff bases chelating resin loaded quaternary ammonium salt (CPS-QA-SBGL) had been synthesized with the cross-linked Polystyrene-Dimethylamine porous beads (CPS-DMA) as raw materials, which were bonded with glycine on the surface via a quaternary ammonium unit as a linker. CPS-QA-SBGL had been characterized by elemental analysis, infrared spectra and thermo-gravimetric analysis (TGA)-differential scanning calorimetry (DSC) analysis. Factors influencing the uptake of heavy metal ions such as pH, initial metal ion concentrations, shaking time and temperature were investigated systematically by batch experiments. The adsorption equilibrium study exhibited that heavy metal ions adsorption of CPS-QA-SBGL followed a Langmuir isotherm model better than a Freundlich model. The optimum adsorption conditions at 298 K were obtained: the initial concentrations of Pb2+, Cd2+, Cu2+ and Cr3+ were 600 mg/L, pH 5, the equilibrium adsorption uptake time was in 30 min. The kinetic data of adsorption of he...

The study on evaporation of water droplet with dissolved salt is important for the understanding of electrospinning and electrospray mass spectrometry experiments. In this work the dynamics of evaporation of water droplet and aqueous droplet with dissolved either LiCl, NaCl or KCl salt in the absence and presence of a homogeneous electric field are comparatively studied by molecular dynamics simulations. The results show that (1) the evaporations of water and aqueous droplets are all accelerated by applying an electric field; (2) the aqueous droplet evaporates slower than the water droplet at low electric field of 0.4 V nm−1, however, its evaporation rate is enhanced significantly and exceeds the water droplet at high electric fields of 0.6 and 0.8 V nm−1; (3) aqueous droplet with dissolved KCl molecules evaporates the fastest, and then followed by dissolved NaCl and LiCl molecules; (4) an optimal salt concentration is observed for the aqueous droplet, above which the evaporation rate is reduced significantly and may cause a electrospinning failure. The present results are qualitatively agree with the observations in the electrospinning experiment and are attributed to the fact that the electric field applied causes the droplet deformation, directional arrangement of water molecules along the electric field direction, acceleration of water molecules due to ions acceleration, as well as hydration effect.

The poly(ethyleneimine) (PEI)-functionalized organic–inorganic hybrid silica was prepared by a hydrothermal-assisted surface grafting technique. Static adsorption experiment results showed that PEI-functionalized hybrid silica had high static adsorption capacity of 68.1 mg g−1, which was 1.3 times as much as that of the sorbents by conventional heating method. PEI-functionalized hybrid silica displayed stable adsorption ability for Pb(II) ions in the range of pH 4–8. An equilibrium state was reached within 30 min. Freundlich and Langmuir adsorption isotherm models were used to fit the equilibrium data, and it was found that the Langmuir adsorption model provided good fit. Kinetic studies indicated that the adsorption followed a pseudo-second-order model. Various thermodynamic parameters, such as ΔGo, ΔHo and ΔSo, were evaluated with results indicating that this system was a spontaneous and endothermic process. The results indicated that PEI-functionalized hybrid silica could be employed as an effective material for the adsorption of Pb(II) ions from aqueous solutions. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.

Four new coordination compounds, namely mononuclear [Zn(pyrtza)2(H2O)2] (1), binuclear [Ni(pyrtza)(H2O)2Cl]2 (2), 1D [Cd(pyrtza)2] (3), and 2D [Mn(pyrtza)Cl] (4), were synthesized by the reactions of Hpyrtza (Hpyrtza = 5-(2-pyrimidyl) tetrazole-2-acetic acid) with MCl2 (M = Zn(II), Ni(II), Cd(II), Mn(II)) in the presence of KOH under solvothermal conditions. The compounds were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. The luminescence properties of the complexes were investigated at room temperature in the solid state. Four new coordination compounds, namely mononuclear [Zn(pyrtza)2(H2O)2] (1), binuclear [Ni(pyrtza) (H2O)2Cl]2 (2), 1D [Cd(pyrtza)2] (3), and 2D [Mn(pyrtza)Cl] (4), were synthesized [Hpyrtza = 5-(2-pyrimidyl) tetrazole-2-acetic acid]. The luminescence properties of the complexes were investigated at room temperature in the solid state.

In this project, coal fly ash was transformed into ceramic materials by adding a certain amount of fusing agent. Ash samples were compacted and sintered with the addition of potassium carbonate (K2CO3·1/2H2O) under a suitable sintering temperature range. Mineralogy and microstructure of the obtained products were characterized by means of X-ray diffraction and field emission scanning electronic microscope techniques respectively. The results indicate that K2CO3·1/2H2O facilitates the transformation of mullite and quartz phases above 800°C, and the mineralogy phases of the product is leucite (KAlSi2O6) and potassium aluminum silicate (KAlSiO4). In the process, K+interacts with oxygen atom and destroys the original lattice. The regular morphology of the sintered samples was confirmed by the observation under SEM, which reveals a uniform dense ceramic is formed at 900°C with the 40wt% addition of K2CO3·1/2H2O.

Poly(ethyleneimine)-functionalized organic-inorganic hybrid silica adsorbent was synthesized by hydrothermal-assisted surface grafting technique for the removal of Ni(II) ions from aqueous solution, and was characterized by FT-IR, nitrogen adsorption and the static adsorption-desorption experiment method. The results indicated that the maximum static adsorption capacity of Ni(II) on poly(ethyleneimine)-functionalized hybrid silica adsorbent by hydrothermal heating method was 1.6 times as much as the conventional heating method. The poly(ethyleneimine)-functionalized hybrid silica adsorbent offered a fast kinetics for the adsorption of Ni(II), had a substantial binding capacity in the range of pH 4-8 and could be used repeatedly. The Langmuir adsorption model was more favorable than the Freundlich and Dubinin-Radushkevich adsorption models. The adsorption followed a pseudo-second-order model compared with pseudo-first-order model. Various thermodynamic parameters such as ΔG°, ΔH° and ΔS° indicated that the adsorption process was spontaneous and endothermic. The results showed that poly(ethyleneimine)-functionalized hybrid silica adsorbent could be employed as an effective material for the removal of Ni(II) ions from aqueous solution.

In this work, molecular dynamics simulation has been adopted to investigate the influence of square-wave alternating electric field on the evaporation of pure water and aqueous nano-films. The evaporation of the films with 3360 water molecules and 0, 1.11 and 2.18 mol L−1 NaCl on a hot gold (1 0 0) surface was analyzed. The results showed that both the evaporation of water and aqueous films were enhanced by applying the alternating electric field. Compared with the liquid films at the absence of the electric field, the maximum evaporation rates increased 1.71, 1.70 and 1.66 times for water film and aqueous films with 1.11 and 2.18 mol L−1 NaCl for the frequency of 500 GHz, respectively. The reasons were inferred that the water film subjected to the time-varying electrical force resulted in increasing of the rotational and translational kinetic energy of water molecules. Thus applying the alternating electric field accelerated the temperature rise of the water film and enhanced thermal volume expansion of the water film. In addition, the interaction between water molecules became weaker and the water molecules escaped from the water film more easily. The MD simulation also showed that the evaporation enhancement was more significant for the alternating electric field parallel to the films surface than in the perpendicular direction.

Quantum chemical calculation is an important method to investigate the molecular structures for multi-atom molecules. The determination of electronic configurations and the accurate description of the symmetry of molecular orbitals are critical for understanding molecular structures. For the molecules belonging to high symmetry group, in the quantum chemical calculation the sub-group is always adopted. Thus the symmetries of some electric states or some molecular orbitals, which belong to different types of representations of high symmetry group, may coincide in the sub-group presentations. Therefore, they cannot be distinguished directly from the sub-group results. In this paper, we provide a method to identify the symmetry of molecular orbitals from the theoretical sub-group results and use this method to determine the symmetry of the highest occupied molecular orbitals (HOMO) of the sulfur hexafluoride SF6 molecule as an example. Especially, as a good insulating material, an important greenhouse gas and a hyper-valent molecule with the high octahedral \begin{document}$ O_h $\end{document} symmetry, SF6 has received wide attention for both the fundamental scientific interest and practical industrial applications. Theoretical work shows that the electronic configuration of ground electronic state \begin{document}$ ^1{\rm A_{1g}} $\end{document} of SF6 is \begin{document}${({\rm {core}})^{22}}{(4{\rm a_{1\rm g}})^2}{(3{{\rm t}_{1\rm u}})^6}{(2{{\rm e}_{\rm g}})^4}{(5{{\rm a}_{1\rm g}})^2}{(4{{\rm t}_{1\rm u}})^6}{(1{{\rm t}_{2\rm g}})^6}{(3{{\rm e}_{\rm g}})^4}{(1{{\rm t}_{2\rm u}})^6}{(5{{\rm t}_{1\rm u}})^6}{(1{{\rm t}_{1\rm g}})^6} $\end{document} and the symmetry of the HOMOs is \begin{document}$ T_{1g} $\end{document}. However, in some literature, the symmetry of HOMOs of SF6 has been written as \begin{document}$ T_{2g} $\end{document} instead of \begin{document}$ T_{1g} $\end{document}. The reason for this mistake lies in the fact that in the ab initial quantum chemical calculation used is the Abelian group \begin{document}$ D_{2h} $\end{document}, which is the sub-group of \begin{document}$ O_h $\end{document}, to describe the symmetries of molecular orbitals of SF6. However, there does not exist the one-to-one matching relationship between the representations of \begin{document}$ D_{2h} $\end{document} group and those of \begin{document}$ O_h $\end{document} group. For example, both irreducible representations \begin{document}$ T_{1g} $\end{document} and \begin{document}$ T_{2g} $\end{document} of \begin{document}$ O_h $\end{document} group are reduced to the sum of \begin{document}$ B_{1g} $\end{document}, \begin{document}$ B_{2g} $\end{document} and \begin{document}$ B_{3g} $\end{document} of \begin{document}$ D_{2h} $\end{document}. So the symmetry of the orbitals needs to be investigated further to identify whether it is \begin{document}$ T_{1g} $\end{document} or \begin{document}$ T_{2g} $\end{document}. In this work, we calculate the orbital functions in the equilibrium structure of ground state of SF6 by using HF/6-311G* method, which is implemented by using the Molpro software. The expressions of the HOMO functions which are triplet degenerate in energy are obtained. Then by exerting the symmetric operations of \begin{document}$ O_h $\end{document} group on three HOMO functions, we obtain their matrix representations and thus their characters. Finally, the symmetry of the HOMOs is verified to be \begin{document}$ T_{1g} $\end{document}. By using this process, we may determine the molecular orbital symmetry of any other molecules with high symmetry group.

In this study, the equilibrium isotherms, kinetics, and thermodynamics of Cu(II), Ni(II), Cd(II), and Pb(II) ions adsorption onto on the surface of poly(ethyleneimine)-functionalized silica from aqueous solution were investigated. The effects of various parameters on the adsorption process, such as contact time, solution pH, initial concentrations of metal ions, and temperature, were studied to optimize the conditions for maximum adsorption. Constant adsorption capacities were seen in the range of pH 4–8. An equilibrium state was reached within 30 min. The experimental values of maximum adsorption capacities for Cu(II), Ni(II), Cd(II), and Pb(II) ions onto poly(ethyleneimine)-functionalized silica gel were 32.7, 28.5, 40.3, and 54.3 mg g−1, respectively. The batch adsorption kinetics was studied for pseudo-first-order model, pseudo-second-order model, Elovich model, and intra-particle diffusion model, and it was found that the pseudo-second-order model was observed to be the best. Freundlich and Langmuir adsorption isotherm models were used to fit the equilibrium data, and it was found that the Langmuir adsorption model provided a good fit. Various thermodynamic parameters such as ΔG°, ΔH°, and ΔS° indicated that the adsorption process was a spontaneous and endothermic process.

Describe an advanced design and manufacturing technology Concurrent Engineering (CE) and give the automobile covering parts mould development flow basing on concurrent engineering. It tries to consider initially all factors of the mould development life cycle. Take an automobile covering part for example. Basing on the finite element analysis software AUTOFORM, do die design and forming simulation. According to the result of simulation, designer can predict the defect of forming and timely modify the forming process. So in stage of process design taking into account the blank forming, this kind of concurrent design of the mould surface can be directly used to mould design, also won't return after the mold design to modify the die-face design process. So on account of concurrent engineering, it can reduce the changes of automobile covering parts mould design and the number of repeated test, improve quality, reduce cost, and shorten the cycle of mould development.

An effective adsorbent for the removal of arsenate from aqueous system was synthesized by loading ferrihydrite on attapulgite (ATP). The effects of various parameters such as heat modified temperature and particle size of ATP, Fe (III) concentrations, adsorbent dosage, solution pH on the removal rate of arsenate were assessed. The results showed that 600 °C modified ATP loaded with Fe (III) sorbent had better arsenate removal efficiency than 200 °C and 400 °C modified ATP. The removal efficiency of As (V) increased significantly with decreasing the particle size of ATP. Arsenate was effectively adsorbed by ATP loaded with Fe (III) sorbent in the pH range of 57. Equilibrium data of arsenic adsorption fitted perfect with Langmuir isotherm model. The removal rate of As (V) by ATP loaded with Fe (III) sorbent was 95.8% at the optimal conditions from drinking water. The results showed that ATP loaded with Fe (III) sorbent can be used for the arsenate removal from aqueous system.

A new chelating resin (CPS-DMA-SABA) was synthesized with the chloromethylated cross-linked polystyrene porous beads (CPS) as raw materials, which were bonded with salicylidene-o-aminobenzoic acid (SABA) on the surface via a quaternary ammonium unit as a linker. The results showed that CPS-DMA-SABA would easily change into a zwitterionic chelating resin (CPS-DMA-SABZ) when washed with distilled water. CPS-DMA-SABA was characterized by elemental analysis, infrared spectra and thermo-gravimetric analysis. The ion sorption capacities of CPS-DMA-SABA were found to be 1916 μg/g for Zn2+ with pH at 4.5, 1620 μg/g for Cu2+ with pH at 6.2, 1291 μg/g for Ni2+ with pH at 6.6 and 780 μg/g for Cr3+ with pH at 5.5, respectively. The experiments showed CPS-DMA-SABA also changed its color when meeting with the metal ion in the aqueous solution. As a consequence, CPS-DMA-SABA can not only be used as a solid phase extractant but also an indicator for confirming the heavy metal ion in solutions.