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β-Cyclodextrin modified magnetic microspheres were synthesized and used as an effective adsorbent for the solid-phase extraction of three phenols from water samples. Scanning electron microscopy an...

This study evaluated the application of the bipolar electrocoagulation catheter via a peripheral-to-central (3 + 1) technique, relative to directly pressing only at the center of the bleeding site (direct-stroke), to effect endoscopic hemostasis of acute non-varicose gastrointestinal bleeding (ANVUGIB). Patients (n = 148) with endoscopically diagnosed ANVUGIB were randomly apportioned to receive treatment by 3 + 1 (n = 78) or direct-stroke (n = 70) application of the bipolar electrocoagulation catheter. The 3 + 1 strategy required pressing at3 narrowly restricted sites equidistant peripheral and center to the site of bleeding. The rates of initial success, hemostasis time, and number of compressions were compared according to intention-to-treat (ITT) or per protocol (PP). The ITT (PP) rate of initial hemostatic success in patients receiving the 3 + 1 catheter was 91.02% (95.9%); and for the direct-stroke group was 71.42% (76.9%). For Forrest IIa lesions specifically, these rates were respectively 91.70% (97.1%) and 63.9% (67.6%). The ITT (PP) hemostasis times of the 3 + 1 and direct-stroke groups were 10.96 ± 3.28 (10.65 ± 2.90) and 14.27 ± 6.58 (14.12 ± 6.67) min; and the number of compressions numbered 5.73 ± 1.98 (5.42 ± 1.46) and 6.47 ± 2.82 (6.16 ± 2.47). During thermocoagulation treatment of ANVUGIB via bipolar electrocoagulation catheter, the 3 + 1 strategy showed a significantly higher rate of successful initial hemostasis relative to the direct-stroke technique, and shorter hemostasis time, with no increase in total procedural steps.

Generating surface-functional microstructures is an effective way to enhance the bonding strength of metal and carbon fiber-reinforced polymer (CFRP). In this study, different microstructural morphologies consisting of two different patterns were generated on the aluminum alloy (A7075) surface via laser processing. The experimental results indicated that different microstructural morphologies contribute to the enhancement of the shear strength of lap joints. The maximum shear strength of these joints was almost four times stronger than that of lap joints without the microstructures. In addition, the investigation indicated that the shear strength was not only determined by surface roughness and contact area but also by the arrangement of different microstructures. These results are mainly due to the combination of mechanical interlocking and physical adhesion. Finally, the corresponding mechanical models of Al-CFRP lap joints were proposed according to the bonding mechanisms and fracture behaviors.

Polymethoxyflavones (PMFs) are widely found in Citri Reticulatae Pericarpium (CRP) and have been investigated with a broad spectrum of biological activities as well as health promoting properties. However, separation of the PMFs from a complex sample, especially preparative separation of these PMFs with high purity, remains challenging. In the present study, an efficient method based on supercritical fluid extraction (SFE) and continuous high-speed counter-current chromatography (HSCCC) has been developed for extracting and preparative purification PMFs from CRP. Various experimental conditions were investigated to optimize the SFE and HSCCC processes. Under these optimized conditions, crude extract of CRP (extract I) was obtained with a maximum contents of nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone and tangeretin. Further extraction of crude extract I was carried out to obtain crude extract II, which was further isolated and purified by HSCCC. It was worth mentioned that continuous injection HSCCC process were realized without lost of separation efficiency, which allowed for multiple purification cycles and therefore saved a lot of labor and time. Furthermore, high-performance liquid chromatography (HPLC) was employed to analyze the fractions separated by HSCCC, which revealed that the purities of the three PMFs were all above 98%. The structures of the three PMFs were identified by LC-MS and 1H NMR spectroscopy.

For researching the influence of high-speed grinding on the surface integrity of cycloid gear, in this paper, the surface of cycloid gear was grinded by high speed grinding process, applied X-ray diffraction to measure the surface residual stress, and the surface roughness and surface hardness were studied. In the experiment, the influence of grinding process parameters (e.g. wheel speed, worktable speed and grinding depth) on material surface integrity (mainly residual stress, surface roughness and surface hardness) was studied by single factor test method. The results show that the linear velocity of grinding wheel has the greatest influence on the residual stress, followed by the speed of worktable, the absolute value of residual stress perpendicular to grinding direction is bigger than that along grinding direction. The surface roughness is improved with the increase of grinding speed and the decrease of grinding depth and table speed. After high-speed grinding, the depth of hardened layer is about 55um, and the hardness of hardened layer is 60-70HV higher than that of base metal.

A freestanding SiO2–TiO2 monolith with bicontinuous structure was prepared via a one pot sol-gel reaction. This monolith was fully characterized by using field emission scanning electron microscopy...

A facile one pot method has been applied to fabricate large-sized freestanding titania-silica monolithic aerogels (TSMA). The obtained TSMA was characterized by scanning electron micrograph (SEM), Energy dispersive spectrometer (EDS), X-ray powder diffraction (XRD) and nitrogen adsorption measurements. SEM results show the TSMA has bicontinuous inner structure and large macropores (through-pores), which are favorable for the liquid infiltration. XRD results demonstrate the TSMA is anatase and nitrogen adsorption results reveal its high specific surface area of 445.9 m2/g. To maximize the catalytic activity of the as-prepared TSMA, an annular photocatalytic reactor has been specially designed and fabricated. With the apparatus, the as-prepared TSMA exhibited outstanding catalytic performance, which degraded glyphosate completely within 180 min of photocatalytic reaction. The kinetic rate (k value) of the photocatalytic reaction reaches 0.0242 min−1. Ion chromatography results indicate that glyphosate was mainly mineralized to inorganic ions such as PO43− and NO3−, etc. Keywords: Facile, Self-supporting, Photocatalytic reactor, Monolithic aerogels, Glyphosate

As a key factor for making decisions for production scheduling, manufacturing capability has been attracted great attention by academia and industries. With the increasing customized and personalized needs, modern manufacturing enterprises need to fabricate products at low cost, at right time, and at high effectiveness. Therefore, it is necessary to optimize the manufacturing system in order to improve productivity and the competitiveness of enterprises. The analysis and evaluation of manufacturing capabilities play an extremely important role in the optimal scheduling of production. In this paper, the manufacturing capability of a job shop is investigated. The indicator system is built for evaluating the manufacturing capability of a job shop and an evaluation method is proposed based on the combination of the entropy weight method and the grey relational analysis. Finally, a case study is used to validate the method.

In this study, an electrical heat-assisted method was adopted to drill a small hole (diameter of 1–3 mm) in hard-to-cut materials, namely, 1Cr18Ni9Ti stainless steel and ZGMn13 high-manganese steel. The flank wear of the twist bit and the surface quality of the small hole were investigated. The relationships among the flank wear, feeding, heating current, and cutting speed were analyzed quantitatively. Flank wear of twist drill directly affected the service life of the drill used in electric hot drilling. The dynamic effects of heating current, cutting speed, and feed rate on the surface roughness and machining hardening of the hole-wall are also discussed. Experimental data indicated that the surface roughness after electric hot drilling can also be obtained by coarse grinding and the surface hardness of the hole-wall had no obvious change. These findings showed that electric hot drilling has irreplaceable advantages in improving the service life of the drill bit and surface quality of the hole-wall.

To solve blood adhesion problems on the surface of medical devices, such as scalpel blades and implants, a hydrophobic and serum-repellent surface was prepared and investigated. First, porous ablated surface on stainless steel (SS) was fabricated via laser processing. Then, the laser-ablated SS (LA-SS) surface was covered by thin tetrahedral amorphous carbon (ta-C) films using a filtered cathodic vacuum arc deposition (FCVAD) technique. As such, a complex surface, i.e., a porous LA-SS surface coated with ta-C films (named as LAC-SS surface), was obtained. The morphologies of the LA-SS surface were tailored by adjusting the scanning rate and laser fluence during laser processing. By decreasing scanning rate, an ablated layer with high-aspect-ratio cavities and large roughness can be fabricated. The wetting tests of water and serum droplets indicated that the LAC-SS surface exhibited excellent hydrophobicity and serum-repellency. Under optimal processing parameters, the wetting behaviors of droplets obey the Cassie-Baxter wetting model. An optimal LAC-SS surface was obtained with a water contact angle of 151.4 ± 1.4° and a serum contact angle of 143.0 ± 1.3°. The optimal surface also demonstrates great anti-adhesive properties with a water sliding angle of 14.1 ± 2.2° and a serum sliding angle of 21.7 ± 2.8°. This optimized complex surface can be used in medical devices to address blood adhesion problems.

A mixed-mode chromatographic stationary phase, C18-DTT (dithiothreitol) silica (SiO2) was prepared through "thiol-ene" click chemistry. The obtained material was characterized by fourier transform infrared spectroscope, nitrogen adsorption analysis and contact angle analysis. Chromatographic performance of the C18-DTT was systemically evaluated by studying the effect of acetonitrile content, pH, buffer concentration of the mobile phase and column temperature. It was demonstrated that the novel stationary phase possessed reversed phase liquid chromatography (RPLC)/hydrophilic interaction liquid chromatography (HILIC) mixed-mode property. The stop-flow test revealed that C18-DTT exhibited excellent compatibility with 100% aqueous mobile phase. Additionally, the stability and column-to-column reproducibility of the C18-DTT material were satisfactory, with relative standard deviations of retention factor of the tested analytes (verapamil, fenbufen, guanine, tetrandrine and nicotinic acid) in the range of 1.82-3.72% and 0.85-1.93%, respectively. Finally, the application of C18-DTT column was demonstrated in the separation of non-steroidal anti-inflammatory drugs, aromatic carboxylic acids, alkaloids, nucleo-analytes and polycyclic aromatic hydrocarbons. It had great resolving power in the analysis of various compounds in HILIC and RPLC chromatographic conditions and was a promising RPLC/HILIC mixed-mode stationary phase.

A method of dispersive liquid-liquid microextraction (DLLME) combined with online derivatization-gas chromatography-mass spectrometry (GC-MS) was developed for the determination of benzophenone-type ultraviolet (UV) filers (BPs) in environmental aqueous samples. It is found that the online derivatization was superior to the off-line derivatization with its simplicity, high reaction efficiency and less consumption of potential poisonous reagents. The influential factors for online derivatization, including the temperature of the injection port, the splitless time, the proportion of derivatization reagent and sample solution, were initially optimized. In addition, the influential factors for DLLME, including the type of the extractant and dispersing solvent, the proportion of the extractant and the dispersing solvent, the volume of sample solution, the pH and the salt concentration of the sample solution were individually optimized in detail. Under the optimized derivatization and DLLME conditions, the limits of detection for the six BPs, benzophenone, 2,4-dihydroxybenzophenone, oxybenzone, 4- hydroxybenzophenone, octabenzone and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, ranged from 0.011 to 0.15 μg/L. The intra-day and inter-day relative standard deviations varied from 0.7% to 16.6%. The method was applied to the analysis of lake and river water with good recoveries. It is cost effective, reliable, easy to operate, environment-friendly and promising in the real applications.