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Background Delayed gastric emptying (DGE) after distal gastrectomy impacts patients’ nutritional status and quality of life. The current treatments of DGE seem unsatisfactory or need invasive interventions. It is unknown whether transcutaneous electroacupuncture (TEA) is effective in treating DGE. Methods A total of 90 eligible participants who underwent distal gastrectomy will be randomly allocated to either the TEA group (n = 60) or the sham transcutaneous electroacupuncture (sham-TEA) group (n = 30). Each participant will receive TEA on the bilateral acupoints of Zusanli (ST36) and Neiguan (PC6) for 4 weeks. The primary outcomes will be the residual rates of radioactivity in the stomach by gastric scintigraphy and total response rates. The secondary outcomes will be endoscopic features, autonomic function, nutritional and psychological status, serum examination, and quality of life (QoL). The adverse events will also be reported. The patients will be followed up 1 year after the treatment. Discussion The findings of this randomized trial will provide high-quality evidence regarding the efficacy and safety of long-term TEA for treating DGE after distal gastrectomy. Trial registration Chinese Clinical Trial Registry ChiCTR2000033965. Registered on 20 June 2020

In this work, we developed a continuous preparation strategy for the production of high-solidscontent waterborne polyurethane (WPU) emulsions via high-gravity-assisted emulsification in a rotating packed bed (RPB) reactor. By adjusting the experimental parameters and formula, WPU emulsions with a high solids content of 55% and a low viscosity were prepared. Preliminary applications of the high-solids-content WPU as a thermally insulating material were demonstrated. RPB emulsification is an economical and environmentally friendly production strategy because of the low energy consumption, short emulsification time, and effective devolatilization. This study demonstrated an effective method for preparation of high-solids-content WPU, moving toward commercialization and industrialization.

Molybdenum disulfide/graphene (MoS2/rGO) nanocomposites are a promising candidate for energy storage materials. However, it is still a challenge to uniformly disperse MoS2 on rGO nanosheets, which the performance mainly depends on. In this work, we demonstrate a novel method to synthesize the three-dimensional (3D) MoS2/rGO nanocomposites by the high-gravity reactive precipitation in a rotating packed bed (RPB) reactor combined with the hydrothermal method. The prepared nanocomposites have higher purity and larger specific surface area than that prepared in the traditional stirred tank reactor (STR). More importantly, MoS2 is uniformly and densely dispersed on rGO nanosheets, resulting in the formation of an even 3D network structure and contributing to the achievement of excellent energy storage performance. The specific capacitance of the nanocomposites reaches 294 F g−1 at a scan rate of 20 mV s−1, which is obviously higher than that of pure MoS2 (122 F g−1) and rGO (23 F g−1). The calculated energy density and power density are 57 Wh kg−1 and 50 W kg−1, respectively. Moreover, the preparation process is environmentally friendly, controllable and suitable for a large-scale production, which is significantly important for the development of the electrode materials applied in the supercapacitors.

Transparent ZnO/polymer nanocomposites with good UV shielding performance have shown great potential applications. Due to the photocatalytic activity of ZnO, core–shell structure nanoparticles (NPs) have been used to fabricate the transparent polymer-based nanocomposites. However, it is still a challenge to synthesize core–shell structure NPs with small particle size and good dispersity, and difficult to maintain the transparency of the nanocomposites because of Rayleigh scattering caused by the big size or the aggregation of NPs. This article reports a novel reverse microemulsion combined with surface modification method for the synthesis of monodispersed silica-coated ZnO (ZnO@SiO2) NPs, which are introduced into ethocel (EC) matrix to fabricate the transparent nanocomposites by the solution-mixing method. The ZnO@SiO2 NPs with an average size of 12 nm have an obvious core–shell structure and show excellent monodispersity in toluene. The as-prepared EC/ZnO@SiO2 nanocomposites shield all the UV light completely under 350 nm and maintain the transparency of pure EC even the solid content reaches 60 parts per hundred of EC resin by weight (phr). Importantly, the photocatalytic activity of ZnO NPs is eliminated thoroughly by the silica shell, which apparently improves the UV aging resistance of polymer (EC), enabling the applications of ZnO as durable and environmental friendly UV blocker in transparent plastics and coatings to extend the lifetime of the products.

Video-assisted thoracoscopic lobectomy with lymphadenectomy is considered one of the most effective treatments for early non-small cell lung cancer. We developed a novel approach for lobectomy in patients with right upper lung cancer through simplified synchronous disconnection of pulmonary arteries and veins. This study aimed to evaluate the feasibility, efficacy, safety, and cost-effectiveness of this minimally invasive technique in managing right upper lobectomy. From March 2016 to September 2017, 62 patients with right upper lung cancer underwent lobectomy via simplified synchronous disconnection of pulmonary arteriovenous by video-assisted thoracoscopic surgery. All patients were followed up for 6–12 months after the procedure through clinic visits or telephone/e-mail interviews. Of the 62 patients (mean age, 57.2 ± 8.7 years), 28 were men (45.2%) and 34 (54.8%) were women. All procedures were successfully performed by thoracoscopy, with a mean operating time of 66.2 ± 9.0 min. The mean blood loss was 40.3 ± 19.5 mL. Only 1 (1.61%) patient required blood transfusion. The mean number of endoscopic linear stapling devices used was 2.6 ± 0.7. The mean number of lymph nodes harvested was 16.0 ± 1.6. Postoperative pneumonia was encountered in 4 (6.45%) patients. There was no postoperative mortality. The mean length of hospital stay was 5.3 ± 1.3 days. Six-month follow-up revealed an excellent clinical result and degree of satisfaction. Simplified synchronous disconnection of pulmonary arteries and veins is a feasible, economical, safe, and effective therapeutic procedure for right upper lung carcinoma. This novel procedure shows promise as a viable surgical approach for right upper lobectomy.

Dental resin-based composites have been used for more than 50 years. The size and the structure of inorganic filler have a great effect on the mechanical properties of the composite resin. In this study, novel micro-sized clusters of hydroxyapatite nanorods (MCHN) were designed and conveniently fabricated by spray drying combined with heat treatment. The effects of the aspect ratio of primary hydroxyapatite nanorods (HN), suspension concentration for spray drying and heat treatment temperature were explored. The results indicated that HN with a lower aspect ratio of 2 (HN-2) and a heat treatment temperature of 500 °C were beneficial to the construction of high-performance MCHN (MCHN-2). As compared to HN-2, MCHN-2 had a further increased filling amount by 10%. More importantly, the flexural strength, flexural modulus and compressive strength of the composite resin were greatly improved by 36.3%, 11.4% and 56.6%, respectively. Therefore, it could be envisioned that MCHN could have a great potential in dental restorative application.

Polyhedral oligomeric silsesquioxane (POSS)-coated nanodiamonds (NDs@POSS) were prepared via the amide formation between amine-functionalized POSS and oxygen-containing groups of NDs. The POSS structures grafted on the surface of NDs enable the NDs@POSS nanocomposites to be well-dispersed in organic solvents and polymers for multifunctional applications. The surface coating of NDs with POSS also bring other incidental advantages such as enhanced thermal stability and superhydrophobic of the NDs. NDs@POSS nanocomposites-embedded hybrid films based on polycarbonate and polyvinyl butyral were fabricated by solution blending methods, showing tunable refractive indexes in the range of 1.49–1.61. Furthermore, the powders of NDs@POSS were superhydrophobic with contact angle of water/air of 154°. Liquid marbles formed by coating the water droplet with NDs@POSS were prepared, and the process intensification effects of the NDs@POSS-based miniature reactors for degradation of methylene and fabrication of Ag nanoparticles were also demonstrated, respectively.

With the development of carbon catalysts, graphene-based metal-free catalysts have drawn increasing attention in both scientific research and in industrial chemical production processes. In recent years, the catalytic activities of metal-free catalysts have significantly improved and they have become promising alternatives to traditional metal-based catalysts. The use of metal-free catalysts greatly improves the sustainability of chemical processes. In view of this, the recent progress in the preparation of graphene-based metal-free catalysts along with their applications in catalytic oxidation, reduction and coupling reactions are summarized in this review. The future trends and challenges for the design of graphenebased materials for industrial organic catalytic reactions with good stabilities and high catalytic performance are also discussed.

Hybrid density functional calculations was used to comprehensively study the electronic structure of S-, Sn- and Pb-monodoped and (Sn, S)- and (Pb, S)-codoped hexagonal WO3 (h-WO3) in order to improve their visible light photocatalytic activity. Results indicate that the (Sn, S)- and (Pb, S)-codoped h-WO3 can realize a significant band gap reduction and prevent the formation of empty states in the valence band of h-WO3, while Sn/Pb-monodoped h-WO3 cannot, because in (Sn, S)- and (Pb, S)-codoping, the S-doping introduces the fully occupied S 3p states in the forbidden band gap of h-WO3 and the acceptor metals (Sn and Pb) would assist the coupling of the introduced S with its nearest O. In particular, the (Sn, S)-codoped h-WO3 has the narrowest band gap of 1.85 eV and highest reducing ability among the doped case. Moreover, the calculated optical absorption spectra show that (Sn, S)-codoping can improve the visible light absorption. In short, these results indicate that the (Sn, S)-codoped h-WO3 is a promising material in solar-driven water splitting.

A facile high-gravity strategy is proposed for preparation of Mg(OH)2/graphene oxide (MGO) composite using a rotating packed bed reactor at room temperature for 1 min. Lamellar Mg(OH)2 nanocrystals of about 60 nm in diameter with a narrow size distribution are distributed homogeneously on the graphene oxide sheets without aggregation. The specific surface area of MGO with mesoporous structure reaches 590 m2 g−1, which is the highest among those reported in the literatures. The as-prepared MGO nanocomposite exhibits excellent adsorption capacity for methylene blue (MB). The removal rate of MB reaches 98% in 1 min. The preparation process of MGO nanocomposite is rapid, simple, and suitable for a large-scale production, and the product has great potential in the field of environmental protection as a promising absorbent.

Here, we demonstrate a facile method to prepare dispersible few-layer graphene sheets (GSs) by NaCl and oxalic acid–assisted solvothermal exfoliation of edge-oxidized graphite (EOG) in presence of polyvinylpyrrolidone under the synergetic effect of short-time ultrasonication. During solvothermal heating process, NaCl, oxalic acid, and PVP adsorbed on the edge/surface of EOG, and oxalic acid decomposed into CO2, CO, and H2O steam weakening the Van der Waals force between sheet layers of EOG. The solvothermal process results in the exfoliation and reduction of EOG to GSs which can be dispersed in various organic solvents with high concentrations (0.10–2.68 mg/mL) and remained stable for 6 months except dimethyl sulfoxide and acetonitrile. The GS film prepared by vacuum filtration method using EtOH phase GS dispersion had a sheet resistance of 28.0 kΩ/□ at a transparency of 81.2%. This method shows great promise for mass synthesis of few-layer graphene dispersions for thin film applications.

Functional organic-inorganic nanocomposites with high transparency show significant potential application in many fields. However, it is still a great challenge to prepare flexible transparent nanocomposites due to the intrinsic stiffness of the nanoparticles and the poor interaction between nanoparticles and organic matrices. In this work, a transparent ternary nanocomposite film with enhanced mechanical performance is fabricated by two-steps. First, the transparent ternary ZnO/MWCNTs/ n -butyl methacrylate (BMA) nanodispersion is prepared by mixing the ZnO/BMA and MWCNTs/BMA dispersions directly. Then, the ternary nanocoposites film is fabricated via in-situ bulk polymerization of the above nanodispersions. As a result, the tensile strength of the ZnO/MWCNTs/poly- n -butyl methacrylate (PBMA) ternary film is enhanced by 42% and the elongation at break is three times that of ZnO/PBMA nanocomposite. The hardness of the film increases from 5B to 1H with 40 wt% ZnO. These results indicate that ZnO and MWCNTs can improve the mechanical properties of the composite significantly. Importantly, the ternary nanocomposite film still remains high transparency and exhibit excellent UV-shielding performance. The as-prepared transparent multifunctional nanocomposite films have promising applications in optical materials and devices, such as optical filters, contact lenses and protection packing.

A new type of transparent sand composed of a fused quartz sand (i.e., glass sand) and the mixture of two white mineral oils is introduced as a material for geotechnical visualized model tests in this paper. The glass sand has the refractive index identical to that of the mixture of two white mineral oils as pore fluid. The transparent sand possesses significant advantages in transparency. In interior natural lighting environment, the transparent sand has a clear visible depth of 14 cm and a maximum visible depth of 20 cm. It also has advantages in non-toxicity and stable nature. Laboratory tests including direct shear, one-dimensional compression, compaction, consolidation-drained triaxial and permeability tests were conducted to demonstrate physical, mechanical, and permeability properties of the transparent sand agree with those of natural sands. As a comparison and reference for the further study, the main properties of available water-saturated fused quartz and transparent sands by other researchers were also summarized in this paper. The transparent sand described here can be broadly applied in visualized model tests in geotechnical and geological engineering fields.

The factor of safety of mechanically stabilized earth (MSE) structures can be analyzed either using limit equilibrium method (LEM) or strength reduction method (SRM) in finite element/difference method. In LEM, the strengths of the reinforcement members and soils are reduced with the same factor. While using the SRM, only soil strength is reduced during the calculation of the factor of safety. This causes inconsistence in calculating the factor of safety of the MSE structures. To overcome this, an iteration method is proposed to consider the strength reduction of the reinforcements in SRM. The method is demonstrated by using PLAXIS, a finite element software. The results show that the factor of safety converges after a few iterations. The reduction of strength has different effects on the factor of safety depending on the properties of the reinforcements and the soil, and failure modes.

The effects of ethylene glycol modified co-precipitation were applied to develop a catalyst with higher activity and selectivity of light olefins in the Fischer–Tropsch synthesis. The catalysts prepared by an ethylene glycol (EG) modified co-precipitation realized smaller and homogeneously distributed catalyst particles as 15–25 nm, which was two times smaller than that of the catalyst prepared from conventional co-precipitation. The Fe/Mn-EG catalyst has higher activity and enhanced selectivity to light olefins, as well as the doubled olefin to paraffin ratio (C2=–C4=/C20–C40), comparing to un-pretreated catalyst. Furthermore, the addition of magnesium promoter to the Fe/Mn-EG catalyst inhibits the chain growth ability, and enhances the formation of light olefins (C2=–C4=), realizing the high selectivity of light olefins as 50.1 %. The properties of catalyst structure, active phase, reduction and carburization of obtained catalysts were characterized by N2 physisorption, XRD, SEM, XPS, TPR and DRIFTS measurements.

A 7.6 m high reinforced embankment-wall system was constructed in stages on very thick soft clay. The reinforced structure incurred a deep-seated global failure at the end of backfill loading. The Strength Reduction Method (SRM) and the Limit Equilibrium Method (LEM) were employed to analyze the stability of the structure. It was found that the SRM captured the deep-seated global failure of the structure through a coupled mechanical and hydraulic Finite Element (FE) modeling. The stability of the reinforced structure was much underestimated or overestimated by the LEM using unconsolidated-undrained or consolidated-undrained shear strength values. However, the stability of the structure could be still captured by the LEM with the increased shear strength values assigned to the consolidated zone directly beneath the reinforced structure and with the unconsolidated-undrained shear strength values assigned to the unconsolidated zone beyond the structure. In practice, both the SRM and the LEM are recommended for stability analyses of geosynthetic-reinforced structures on soft ground considering hardening of the soil so that the results from the two methods can be cross-examined.

Tension measurement of geogrid is essential in reinforcement mechanisms studies. Geogrid is a nonlinear flexible material with large apertures, it is difficult to measure the tensions mobilized in geogrid, especially in scaled-down geogrid in centrifuge modeling. In this study, strain gauges were glued onto the surface of model geogrid with epoxy resin and were calibrated through multi-stage and continuous tensile tests. Generalized Kelvin model was used to fit the constitutive curves from the tensile tests. The model is capable to describe time-dependent and nonlinear behavior of the composite material of epoxy resin and model geogrid. Based on generalized Kelvin model, tensions in the model geogrid were measured in a centrifugal modeling of a reinforced embankment on soft clay. A finite element model was developed to simulate the centrifuge modeling and a comparison was carried out between the computed and measured tensions. The numerical results basically captured the measured reinforcements, indicating that the method of reinforcement measurement proposed in this study is appropriate and reasonable.

Several different proteins expressed in embryogenic and nonembryogenic Eruca sativa calli were identified by combining one-dimensional SDS-PAGE protein mapping with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. By querying the widely recognized MASCOT search engine, it was found that three of the proteins that were particularly strongly expressed in the embryogenic callus represented sucrose synthase, phospholipase D, and enolase, respectively. RT-PCR analysis also confirmed that the gene coding for enolase was transcribed especially strongly in the embryogenic callus but not in nonembyogenic callus. Finally, the relationship between the three proteins and somatic embryogenesis is discussed.

Docking simulation between chlorogenic acid and H5N1 influenza virus neuraminidase (NA) was performed and the binding free energies of the best pose and average for the best three different poses of H5N1 NA–chlorogenic acid complex are −9.71 and −9.27 kcal/mol, respectively, which is lower than those of H5N1 NA–oseltamivir complex (−7.13 and −6.39 kcal/mol) by using ArgusLab docking method. The hydrogen bonds could be formed between chlorogenic acid and the H5N1 NA amino acid residues Arg156 and Thr439. Arg152 from the 150-cavity makes polar contact with the –COOH group in chlorogenic acid. Chlorogenic acid could be a potential H5N1 influenza A virus NA inhibitor.

We investigate the classical and quantum aspects of non-commutative topological (Chern–Simons) mechanics. We introduce the magnetic field by the minimal substitution in a way which preserves the original symplectic structures. We find that the classical aspect, say, the solutions to the equations of motion, converges to the reduced theory which is obtained by turning off the mass term smoothly. However, the quantum aspect, i.e., the spectra and the angular momenta, does not have such continuous limits. The spectra will become divergent when the mass term is turned off. A scheme is proposed to regularize the spectra so as to get a finite result. In order to verify our regularization scheme, we resort to Dirac theory. We find that there are two constraints during the reduction from the full theory to the reduced one which alter the symplectic structures. The eigenvalues of angular momenta also have no continuous limits, and this situation is similar to the one which has been studied some years ago. The possibility of taking an additional limit is also discussed.

A centrifugal model test was performed to investigate the behavior of a geogrid-reinforced embankment on a 20 m thick soft silty clay subsoil. The lime-stabilized soil embankment was 4 m high, 26 m wide with slopes of 1:1.5 and included sand wick drains. Displacements, earth pressures and pore water pressures were measured during the test. Test results showed settlement on the front face of the foundation was approximately 90% of that measured by displacement sensors; the elastic displacement was approximately 11% of the total displacement; and the reinforced embankment remained serviceable despite a 300 mm wide crack on the embankment surface and up to 1.73 m settlement at the centerline of the embankment.

The spectra of a charged harmonic oscillator minimally coupled to a perpendicular magnetic field in the non-commutative plane are studied by using the path integral formulation. We get the spectra in a mapping-independent way. Interestingly, we find that the spectra have no continuous limit when the dimensionless parameter tends to zero. In order to get a finite result, a truncation is inevitable. Finally, we give a reasonable explanation of truncation from the constrained theory point of view.

We propose a mapping-independent method to analyze the spectra of the non-commutative two-dimensional harmonic oscillator. The path integral formulation is applied and an effective Lagrangian is obtained. The spectra are read off directly and the question of uniqueness is answered.

Drug particle physical properties are critical for the efficiency of a drug delivered to the lung. The purpose of this study was to produce ultrafine sumatriptan succinate particles for inhalation.Sumatriptan succinate particles were produced via reactive precipitation without any surfactants. Several low toxic organic solvents such as acetone, isopropanol, and tetrahydrofuran were investigated as the reaction medium. And the dry powder was obtained via spray drying. FT-IR, HPLC, SEM and XRD were exploited to characterize the physicochemical properties of the ultrafine sumatriptan succinate dry powder. The aerosol performance of the powder was evaluated using an Aeroliser connected to a multi stage liquid impinger operating at 60 l/min.The mean particle size of the ultrafine sumatriptan succinate particles obtained under optimum conditions was in the range of 630-679 nm and consequently they were in the respirable range. The spray-dried powder whose fine particle fraction was increased up to 50.6 +/- 8.2% showed good aerosol performance whereas the vacuum-dried powder was approximate 18.2 +/- 3.0%.Good aerosol performance ultrafine sumatriptan succinate particles could be produced by reactive precipitation without any additives followed by spray drying at the optimum parameters.

The spectra and wave functions of the 2-dimensional harmonic oscillator in a noncommutative plane are revised by using the path integral formulation in coordinate space and momentum space, respectively. We perform the path integral formulation in coordinate space first. Then we study this problem in momentum space. The propagator is computed both in coordinate space and in momentum space. The modification due to noncommutativity of eigenvalues and eigenfunctions is studied. Both the small and large noncommutative parameter limits are discussed.

A gas-microemulsion reaction precipitation method was employed to prepare nano-Ce0.5Zr0.5O2 by absorption of NH3 into water-in-oil (W/O) microemulsion in a rotor–stator reactor . The effects of different operating conditions including final pH of the microemulsion, reaction temperature, initial Ce3+ and Zr4+ concentration, rotation speed, and gas–liquid volumetric ratio were investigated. Nano-Ce0.5Zr0.5O2 with an average diameter of about 5.5 nm, a specific surface area of 215.6 m2/g and a size distribution of 4–8 nm was obtained under the optimum operating conditions. The as-prepared nano-Ce0.5Zr0.5O2 was loaded with Au to prepare nano-Au/Ce0.5Zr0.5O2 catalyst which was subsequently used for CO oxidation test. CO conversion rate reached 100 % at room temperature, indicating high catalytic activity of the nano-Au/Ce0.5Zr0.5O2 catalyst.

In this paper, composite particles of nano zinc oxide coated with titanium dioxide were prepared and characterized by TEM, XRD, XPS and FT-IR, and the properties of the composite particles for photo catalysis and light absorption were studied. Tetrabutyl titanate (TBT) was hydrolyzed in an alcoholic suspension of nano zinc oxide with diethanolamine (DEA) as an additive, resulting in a film with a thickness of 20–30 nm being coated on the surface of nano zinc oxide, and the composite particles contained ZnTiO3 after drying and calcination. Photocatalysis capabilities of the composite particles for the degradation of phenol in an aqueous solution were greatly improved as compared with nano zinc oxide particles before coating, with pure nano ZnO and nano TiO2 with similar average sizes, or with the mixture of nano ZnO and TiO2 with the similar composition as the composite particles. The light absorption scope of the composite particles was enlarged when compared to nano titanium dioxide with same average size.

Ag-SiO2 composite hollow nanospheres were synthesized by impregnation of hollow silica nanospheres (HSNSs), which were prepared by templating CaCO3 nanoparticles, in [Ag(NH3)2]NO3 aqueous solution followed by heat treatment. The straightforward process generates composite materials containing Ag nanoparticles, with the average size of 6–10 nm in diameter, uniformly dispersed and mainly distributed on the shells or between the spaces of the HSNSs. The Ag-supported HSNSs were characterized through TEM, EDS, and XPS. Furthermore, ASS, XRD and UV-Vis analyses demonstrated that higher loading efficiency could be achieved under the optimum loading conditions of a silver precursor solution of 0.08 M, pH = 9.0 and HSNSs with a BET surface area of 830.4 m2/g.

A geochemical model describing the solubility of actinides in underground water at the Waste Isolation Pilot Plant (WIPP) Project is under development. The database for this model consists of standard chemical potentials and Pitzer model parameters for hundreds of species that may be present in the WIPP disposal room. Organic ligands used in separation and decontamination processes may be present in the nuclear wastes placed in the WIPP site and could have a significant impact on mobile actinide concentrations. In this work the β1 and β2 stability constants of NpO2 +, UO2 2+, Am3+ and Th4+ with the oxalate anion have been measured in 0.3–5.0M NaCl media at 25 °C by a solvent extraction technique. For the 1:1 complexation, the values of the stability constants increased in the order: NpO2 +

Two novel engineered bacteria, BL21(DE3)/pETCA1S and TG1/pSuperCA1S, were obtained which can secretory express the gene encoding glutaryl 7-amino-cephalosporanic acid acylase (GL-7ACA acylase) from Pseudomonas sp. 130 with high activity. The growth conditions of transformants for overproduction of GL-7ACA acylase were optimized: in intact cells of BL21(DE3)/pETCA1S and TG1/pSuperCA1S the activity of GL-7ACA acylase was 415 and 600 units g−1 dry cells, respectively. The highest specific activity of GL-7-ACA acylase is in the intact cell as compared with that of transformants constructed in our laboratory. In fiftieth generation of mutants transferred on agar plates the specific activity of GL-7ACA acylase remained constant.

The stability constants of NpO 2 + , UO 2 2+ Am3+, and Th4+ with acetate and lactate anions has been measured in 0.3–5.0m NaCl media at 25°C by the solvent extraction technique. For the 1:1 complexation, the values of the stability constants increased in the order: NpO 2 + < Am3+ < 2 2+ < Th4+, in accordance with the actinide charge density and reflecting the strongly ionic bonding of the complexes. The Pitzer ionic interaction parameters were calculated and used to estimate the thermodynamic stability constants at I = 0. Because our data were collected mainly in the high ionic strength region values of β(1) were estimated from values reported in the literature. For all stability constants the Pitzer model gives an excellent representation of the data using three interaction parameters β(0), β(1), and Cφ

Epoxy resin (EP) is used widely nowadays as a structural, adhesive and electronic material due to exhibiting high strength, high elastic modulus, high insulation etc. [1]. However, EP may show limitations, especially over-fragility in application, so other constituents have to be added to improve its performance. Methods of toughening EP has long been sought, and one of the most common methods is the incorporation into EP of a dispersed rubbery elastomer, which can enhance impact strenght of EP at the expense of weakening rigidity and heat-resistance of the matrix as well as raising cost [2]. Calcium carbonate is considered as a suitable substitute for rubbery elastomer in EP matrix because it demonstrates high rigidity and may overcome the shortcomings of rubbery elastomer if incorporated well into the EP matrix. Traditionally, micron-sized calcium carbonate is added into polymers for the purpose of reducing formulation cost of the polymer-based composites. Nevertheless, micron-sized calcium carbonate may have negative impact on the mechnical performance of polymers. It was reported that mechanical properties of polymers could be otherwise improved by adding nano-sized fillers. Generally, mechanical behaviors of particulate-filled polymers, which have a very complex dependence on the interfacial bonding between the filler and the matrix, are influenced strongly by factors such as size, content and shape of the filler. Of these fillers, nano-sized calcium carbonate (nano-CaCO3) particles have attracted considerable attention and play effective role in many composite systems [3]. This work reports an investigation of the influence of nano-CaCO3 on the mechanical properties fo EP composite. Nano-CaCO3 employed in this experiment, with a cubic shape and an average diameter of 40 nm (Fig. 1), was synthesized by the reactive precipitation reaction method under high gravity environment. Detailed methodology and basic theory about the preparation of nano-CaCO3 by this method can be found in the reference [4]. The dispersion degree of the filler in the matrix will significantly influence the properties of composite. However, it is very difficult to disperse nano-sized particles in a high viscous polymer matrix. Generl method is to introduce a high shearing force to the mixture in order to intermix the fillers with the matrix [5].

TiO2 is extensively used in materials-coloring field as an excellent white pigment. An increasing interest focuses on the surface coating modification of TiO2 in order to improve the application performance in polymer matrix [1–3]. Martin Arellano et al. studied the surface modification of TiO2 powder and presented an evaluation method [1]. Noman S. Allen et al. investigated the photochemical and thermochemical behavior of TiO2 pigments [2]. Nano-CaCO3 is an important inorganic material whose toughening and strengthening functions in plastics have been verified [4–6]. In this paper, nano-CaCO3 synthesized by a high gravity reactive precipitation method was employed as a new pigment dispersant, blending with TiO2 and other additives to prepare complex master batches for use in the coloring of polypropylene (PP). The influence of the synergism of CaCO3 and TiO2 on the performance of colored PP products is discussed. Nano-CaCO3, TiO2 and other additives were stirred uniformly in a high speed mixer followed by blending in a double roll plasticator. The blended sample was crushed and extruded in a single screw extruder to prepare nanosized complex color masterbatch, which was subsequently blended with PP resin in a plastic jetting-molding machine to yield colored products. Whiteness measurements were performed by a TC– P II G Auto Color Difference Meter (Beijing Optical Instrument Factory, China, Hunter’s L, a, b color space, 0/d geometrical conditions, 10 ◦ field of view, TW whiteness formula). Ultraviolet (UV) absorption characteristics of the samples were determined by a UV2501-PC Spectrometry (Shimadzu, Japan). The dispersion extent of TiO2 in PP was observed by a H-800 transmission electron microscope (TEM) (Hitachi, Japan). The rheology of the samples was examined by a PLV-151 Brabender torque rheometer (Brabender, Germany, temperature = 210 ◦C, rotating speed = 30 rpm). Fig. 1 shows the TW whiteness index of the composites with a fixed total amount of nano-CaCO3 and TiO2 added, while TiO2 is partially replaced by nanoCaCO3 at different doses. It can be seen from Fig. 1 that a partial substitution of nano-CaCO3 for TiO2 can raise the whiteness of colored PP. The whiteness index of the materials reaches a maximum when 10% of TiO2 is replaced by nano-CaCO3, which is 4.3% higher than those without any replacements of TiO2 by nanoCaCO3. This is because nano-CaCO3 can prompt the dispersion of TiO2 particles in the matrix and boost the coloring effects of the materials. The doses of TiO2 also reduce accordingly. Fig. 2 shows the UV absorbency (Abs.) curves of TiO2 and nano-CaCO3 powders. It can be seen from Fig. 2 that TiO2 exhibits a very strong absorbency for the UV light in the wavelength of 290–400 nm, while the absorbency of nano-CaCO3 is notably lower than that of TiO2 in this wavelength range. Fig. 3 shows that UV absorbency curves of colored PP. The UV absorbency of colored PP changes little when TiO2 is partially replaced by nano-CaCO3. Because nano-CaCO3 can improve the dispersion of TiO2 in PP matrix, the UV absorptance of TiO2 remains unchanged even if its concentration is lowered. This result is favorable for the reduction of the product cost while maintaining a good aging resistance performance. Fig. 4 shows the TEM pictures of PP/TiO2/CaCO3 composites. Fig. 4a is the TEM picture of PP/TiO2, without any addition of nano-CaCO3. It is obvious that large aggregates form in this system. Fig. 4b is the TEM picture of PP/TiO2/CaCO3, while the concentration of TiO2 keeps unchanged and the dose of nano-CaCO3 accounts for 10% of the dose of TiO2. Fig. 4c is the TEM picture of PP/TiO2/CaCO3, while the total concentration of TiO2 and nano-CaCO3 combined remains

This paper describes a new model to calculate the mean activity coefficients of dissociated electrolytes in concentrated solutions. It is based on three assumptions: (i) a quasi-lattice arrangements of ions in solution; (ii) a contribution from ion-water interactions to the mean activity coefficients; (iii) a concentration dependence of the dielectric constant. The mean activity coefficients of thirteen strong electrolytes from moderately dilute solutions to saturated solutions are found to correlate well by this model. For dilute solutions, a limiting equation in which only ion-specific parameters are required is proposed. It is suggested that specific ionwater interactions might be the major source of the nonideality of strong electrolyte solutions at high concentrations.

This paper studies the joint estimation problem of ranges, DOAs, and frequencies of near-field narrowband sources and proposes a new computationally efficient algorithm, which employs a symmetric uniform linear array, uses eigenvalues together with the corresponding eigenvectors of two properly designed matrices to estimate signal parameters, and does not require searching for spectral peak or pairing among parameters. In addition, the proposed algorithm can be applied in arbitrary Gaussian noise environment since it is based on the fourth-order cumulants, which is verified by extensive computer simulations.

Inorganic and organic double templates were used to fabricate silica nanospheres and nanotubes with nanochannels perpendicular to the shells. Sphere and needle like CaCO3 nanoparticles, synthesized by a high gravity reactive precipitation method, were used as inorganic templates and C16H33N(CH3)3Br (C16-CTAB) was used as an organic surfactant template. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) were employed to characterize the nanoporous structure. The nanochannels were found perpendicular to the surface of nanospheres and nanotubes. The size of nanochannels is about 3~5 nm. The size of hollow nanosphers and nanotubes can be controlled by the inorganic CaCO3 nanoparticle templates and the nanochannels in the shells can be tuned by different surfactant micelles. The nanospheres and nanotubes with nanochannels perpendicular to the shells have a potential application in chemical bio-catalyst, bio-separation, and drug delivery.

Oxotitanium phthalocyanine (TiOPc) is an ideal photoconductive material and electrophotographic photoreceptor since it exhibits remarkable absorption and photosensitivity properties in the visible and near-infrared wavelength region, which lead to the generation of free carriers with a high quantum yield [1]. It was reported that Y-type TiOPc had the most excellent photosensitive properties among five typical crystal forms of TiOPc [2–7]. In conventional routes, TiOPc of other crystal forms are usually synthesized and then transformed to Y-type TiOPc by processes such as thermomechanical, solvent, acid treatment and mechanical grinding. Solvent treatment is preferred among these processes due to its convenience and high efficiency where TiOPc is subjected to crystal transformation in the presence of water, aromatic compounds, alcohol, ketone, ether and their derivatives. Since Chen et al. [8] reported that photoconductivity of TiOPc depended on particle size, many works have been directed to obtaining nanosized Y-type TiOPc by different methods. In this paper, Y-type TiOPc is synthesized under high gravity environment created by a rotating packed bed (RPB) reactor, which can greatly intensify micromixing and mass transfer between fluids. Advantages of the high gravity method in synthesizing nanosized inorganic materials have been reported in our previous works [9, 10].