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Wear behavior of a single-phase laser-clad Cu-9Ni-6Sn coating was investigated against high-carbon steel ball in a ball-on-disc linear wear tester in air and in a 3.5 wt.% NaCl solution, compared with the commercial wear-resistant Cu-10Ni alloy. The wear resistance of a single-phase laser-clad Cu-9Ni-6Sn coating was higher than that of Cu-10Ni alloy in both air and NaCl solution. For the sliding process in air, a continuous, compacted and adherent oxide layer was formed on the sliding surface of Cu-9Ni-6Sn coating due to the combined effects of spinodal decomposition, Sn-rich precipitates and grain refinement. In contrast, such a layer was not seen on the sliding surface of Cu-10Ni alloy. For the sliding process in NaCl solution, Cu-9Ni-6Sn coating exhibited the high hardness and excellent corrosion resistance compared to Cu-10Ni alloy, which was responsible for the better wear resistance of Cu-9Ni-6Sn coating. Clearly, a single-phase laser-clad Cu-9Ni-6Sn coating exhibited the high wear resistance in both air and NaCl solution, resulting in the excellent application prospect in many industries.

Two Cu-9Ni-6Sn coatings with and without Sn-rich precipitates were obtained by laser-cladding. For two cross-section of coatings, the corrosion resistance can be graded in the order as equiaxed dendrite zone > dendrite zone > planar zone > Fe substrate due to the difference in composition and microstructure of the four zones. The coating with Sn-rich precipitates suffered severe localized corrosion, whereas general corrosion morphology was presented for the coating without Sn-rich precipitates. Clearly, a single-phase coating with large equiaxed dendrite zone should be developed by optimizing laser parameters for prolong the service life.

Aim. To examine whether the baseline 25-hydroxyvitamin D [25(OH)D] level was predictive of the onset of prediabetes or type 2 diabetes (T2DM) in the Chinese population. Methods. This was a 4-year follow-up study that was conducted in the Chengdu region of China as part of the China National Diabetes and Metabolic Disorders Study. The study included 490 participants that were free of prediabetes and type 2 diabetes mellitus (T2DM) at baseline and had complete data by follow-up examinations. Glucose, insulin, and 25(OH)D levels were measured at baseline and at 4 years later. Prediabetes and T2DM were defined by results obtained from an oral glucose tolerance test. Results. Over a 4-year follow-up, 95 (48.5‰) developed prediabetes and 31 (15.8‰) individuals developed diabetes. Low 25(OH)D status was significantly associated with the risk of developing prediabetes [OR 3.01 (95% CI: 1.50–6.06), P=0.002] and T2DM [OR 5.61 (95% CI: 1.73–18.27), P=0.004] after adjustment for multiple potential confounders. In a multiple linear regression analysis, low baseline levels of 25(OH)D were an independent predictor of increased insulin resistance over a 4-year period (P<0.05). Conclusions. The current prospective study suggests that low 25(OH)D levels might have contributed to the incidence of prediabetes or T2DM in Chinese individuals. This trial is registered with TR-CCH-ChiCTR-OCS-09000361.

(Ti, W)C reinforced stainless steel coatings were fabricated by plasma cladding for investigating the role of (Ti, W)C particles on microstructure, cyclic oxidation and high-temperature wear resistance of the coatings. (Ti, W)C particles were uniformly dispersed in the coatings and exhibited a diffusion-metallurgical bond with the (Fe, Ni) matrix. Although adding (Ti, W)C to the coating reduced the oxidation resistance due to the low thermal stability of these carbides, the rapid formation and thickening of oxide scale could alleviate the sticking problem in actual rolling condition. Moreover, (Ti, W)C addition resulted in the rapid formation and excellent maintenance of the tribo-oxide glaze during the sliding process, which remarkably improved the wear resistance and reduced the coefficient of friction.

The effect of solution pH, Cl− concentration and temperature on the electrochemical corrosion behavior of PH13-8Mo steel in acidic solution was investigated by using the electrochemical tests, scanning electron microscopy and X-ray photoelectron spectroscopy. The PH13-8Mo martensitic precipitation hardened stainless steel is in the passivity state when the pH value is above 3.0, below which the anodic polarization curves of the steel are actively dissolved. The corrosion current density gradually decreases with increasing the solution pH and decreasing Cl− concentration and solution temperature. Pits are initiated on the sample surface in the presence of the Cl− and gradually developed into uniform corrosion with increasing the Cl− concentrations. Moreover, the corrosion is more serious with an increase in solution temperature.

Fe-9Cr, Fe-9Cr-1Mo and Fe-9Cr-0.5Mo-0.5Ni (wt%) alloys have been prepared for studying the effect of (Mo, Mo/Ni) on carbide precipitation, oxidation behavior and high-temperature tensile property of Fe-9Cr alloy. Rod-shaped Cr23C6 precipitates in Fe-9Cr alloy were refined and spheroidized by Mo addition, while Mo/Ni addition had no impact on Cr23C6 precipitates. Adding (Mo, Mo/Ni) to Fe-9Cr alloy reduced inward oxygen diffusion and the growth rate of an inner Cr-rich layer, thereby accelerating chromia formation and improving the oxidation resistance. High-temperature strength of Fe-9Cr alloy was also enhanced by alloying elements (Mo, Mo/Ni).

BIER (Bit Index Explicit Replication) is a novel solution for multicast. Although it has not been applied to real network, without establishing a multicast tree and maintaining per-flow state, BIER has obvious advantages over existing multicast tree-based routing solution. However, we found data redundancy in large-scale network when BIER domain has more than one SDs (Sub Domains) or SIs (Set Ids). In fact, some of them can be decreased. This paper proposed HF-BIER (Hierarchical Forwarding Bit Index Explicit Replication) model which is able to decrease the data redundancy. In order to add multicast control information, we set up Transfer BFR and LL (Logical Level) in HF-BIER model. This paper describes the forwarding mechanism of HF-BIER, and figures out the workflow of control plane and data plane of HF-BIER. Finally, simulation has been made to prove HF-BIER can effectively reduce the forwarding redundancy in the core network and critical links.

In the transmission process of crude oil gathering system, water-assisted heat transfer is often used to avoid wax formation, and pipeline temperature and pressure control are often controlled manually. In order to improve control efficiency and save labor cost. In this paper, we propose a DQN-based algorithm. The intensive learning model completes the temperature and pressure control in the pipeline. At the same time, because these two parameters have strong coupling, which affects the global control, this paper focuses on the joint optimization of valve opening and heating furnace and pressure pump. Finally, in order to verify the effectiveness of the system, the simulation control experiment is adopted. The test results show that the system control effect is excellent and the robustness is good.

The effect of strain aging on the microstructure, including copper precipitation, and mechanical properties of an industrially produced Cu-containing microalloyed low carbon pipeline steel has been investigated. The precipitation of round bcc-Cu particles with diameters of ∼7 nm has been clearly observed in the microstructure after strain aging. The strength of pipeline steel significantly increased while the elongation and impact toughness did not apparently decrease. Unlike welded pipe, few carbon atoms in supersaturated solid solution diffuse to the mobile dislocations, forming Cottrell atmospheres and producing strain aging phenomenon in seamless pipe. This difference is attributed to the different pipe making technique: thermo mechanically controlled processed for welded pipe and traditional heat-treatment for seamless pipe.

TiC–Cr7C3–CNTs cermet coating on 304 stainless steel substrate was prepared using a newly developed in situ technology consisting of self-propagation high-temperature synthesis reaction, laser cladding and metal dusting techniques. The samples were subjected to various microstructure examinations and their corrosion behaviour was compared with that of 304SS in 1 mol L− 1 HCl solution. The results showed that high quality of the coating was obtained. Many reinforcements were more or less uniformly distributed within the grain and grain boundary in the microstructure. Carbon nanotubes (CNTs) were obviously observed, but the length of CNTs was shorter after laser cladding. Compared with the 304SS substrate, the coating has no pitting and maintained a low corrosion rate in 1 mol L− 1 HCl solution.

A novel method is developed for low temperature synthesis of carbon encapsulated spherical Fe7S8 nanocrystals with core–shell structure (Fe7S8@C) by the reaction of ferrocene with ammonium persulphate. The phase structure, morphology, specific surface area and composition of the nanocomposite are systematically characterized. It is found that the Fe7S8 nanocrystals with a weight percent of 33.5% have a median size of 25.2 nm. The Fe7S8@C electrodes retain a reversible capacity of 815 and 539 mAh g−1 after 50 cycles at a current density of 200 and 2284 mA g−1, respectively. The high capacity, good cycling behavior and rate capability of Fe7S8@C electrodes are attributed to the good protection and electrical conductivity of carbon shell.

A Mo2NiB2 cermet coating on steel substrate was fabricated by laser cladding technique. The laser cladding samples were subjected to various microstructure examinations, hardness, and wear and corrosion tests. The results showed that a continuous, dense and adherent laser-clad coating was formed on the steel substrate. The coating consisted of γ-(Fe, Ni) as a metallic matrix binder and Mo2NiB2 particles as a reinforced phase distributed uniformly in the microstructure. Average hardness of the coating up to 700 HV was significantly higher than that of the matrix 150 HV. The coating exhibited a dry-sliding wear resistance that was increased by about 6 times relative to the steel substrate. Extensive pits formation on the surface and through the inner part had taken place for 304 stainless steel, while it disappeared in the coating.

The recently developed “quenching and partitioning” and “quenching-partitioning-tempering” heat treatment are both novel processing technologies, which are aim to achieve advanced high strength steels with good combination of high strength and ductility. Containing certain amount of ductile austenite phase is a key characteristic of the quenching and partitioning steel, and austenite phase is being enriched with carbon during the partitioning treatment. However, the microstructural evolution of the quenching and partitioning steel during the heat treatment is rather complicated. In present work, evolution of microstructure in medium carbon steel containing Cr, Mo and Nb has been studied in detail during the quenching and partitioning process. The microstructural evolution of the steel was investigated in terms of X-ray diffraction, scanning electron microscope and transmission electron microscope.

Corrosion behavior of low-alloy steel containing 1% Cr (1Cr) with normalized (ferritic–pearlitic) and quenched-and-tempered (tempered martensitic) microstructures was investigated in CO 2 environments at 60 °C. The severe localized corrosion which was observed in N80 carbon steel, did not exist for 1Cr steel due to the formation of a compact and self-repairable Cr-rich scale. For 1Cr steel, the corrosion resistance with ferritic–pearlitic microstructure was better than that with tempered martensitic microstructure. An apparent corrosion scale spallation was observed on the surface of quenched-and-tempered 1Cr steel, while only slight scale spallation was seen for normalized 1Cr steel.

To enhance the wear resistance of mechanical components, laser cladding has been applied to deposit in situ VC–Cr7C3 ceramic coating on steel substrate using a pre-placed powder consisting of vanadium, carbon and high-carbon ferrochrome. The laser cladding samples were subjected to various microstructure examinations, microhardness and wear tests. The results showed that defect-free coating with metallurgical joint to the steel substrate was obtained. The quantity of VC–Cr7C3 particles gradually increased from the bottom to the top of the coating. The VC particles in nanometer were observed within the coating. Average hardness of the coating up to 1050 HV was significantly higher than that of the substrate 150 HV. Wear tests indicated the wear resistance of the clad coating was 4 times that of the steel substrate.

Aims/Introduction The goal of this study was to evaluate the effect of Roux-en-Y gastric bypass (RYGB) on hyperglycemia and gastrointestinal hormones in Chinese obese type 2 diabetic patients with body mass index (BMI) between 28 and 35 kg/m2. Materials and Methods A total of eight obese type 2 diabetes patients with BMI 28–35 kg/m2 who underwent RYGB and 10 obese normal glucose tolerance (NGT) patients with no surgery were identified. BMI and blood glucose on baseline, and 2–4 months postoperative, changes of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide YY (PYY), and oxyntomodulin (OXM) were recorded. Efficacy of RYGB was defined by the percentage of excess weight loss (%EWL) and amelioration of type 2 diabetes. Results The %EWL was 53.00 ± 26.25% in 2 month and 63.65 ± 33.71% in 4 month. Glycated hemoglobin changed from 7.2 ± 1.0% preoperative to 6.2 ± 0.9% in 2 month and 6.3 ± 1.2% in 4 month postoperative. The improvement rate of type 2 diabetes 4 months after RYGB was 83.3%. After surgery, area under the curve (AUC) GLP-1 120 increased with no significance. AUC PYY 120 changed from 10.37 ± 5.45 pmol/L/min preoperative to 22.19 ± 10.61 pmol/L/min in 2 month and 22.04 ± 7.73 pmol/L/min in 4 month postoperative. Postoperative AUC OXM 120 was also higher than that of the preoperative level. AUC GIP 120 decreased from 13.06 ± 8.45 pg/mL/min preoperative to 8.71 ± 3.28 pg/ml/min in 2 month and 6.88 ± 2.33 pg/mL/min in 4 month postoperative. Conclusions Roux-en-Y gastric bypass has a beneficial effect on weight loss and glucose metabolism in obese type 2 diabetes patients with lower BMI. Postoperative concentrations of GLP-1, PYY and OXM increased, whereas GIP decreased.

In this work, Mo was investigated as an additive for in situ preparation of TiC/Al composite using a casting route assisted by self-propagating high-temperature synthesis (SHS). Experimental results show Mo improves the wettability between TiC phase and aluminium melt due to the formation of a Mo-rich shell around the formed TiC particles, which is a kind of good modificator. Compared with the composite without added Mo, 1.0 wt.% Mo addition developed finer matrix structure, significant refinement of TiC particles and more uniform distribution of TiC particles in the matrix. Meanwhile, both wear and tensile properties of TiC/Al composite were improved with 1.0 wt.% Mo addition and then deteriorated with the further increase of Mo content due to the formation of fragile phase Al 5 Mo.

TiC particle-reinforced 304 stainless steels were prepared using a new developed in situ technology and their corrosion behavior was compared with that of 304SS in 5 wt.% HCl solution. As compared to 304SS, Ecorr, Epit and Erp values had shifted to a more negative region in 304SS containing TiC, indicating faster corrosion rate by TiC addition. The addition of TiC particles to 304SS resulted in no rapid pit propagation but maintained a high corrosion rate in the whole immersion time investigated.

The corrosion behavior of TiC particle-reinforced 2Cr13 stainless steels prepared by in situ reaction and electroslag remelting (ESR) was investigated using potentiodynamic polarisation measurements and immersion tests. The addition of TiC particles to 2Cr13 stainless steel impeded rapid pit propagation but maintained a high corrosion rate in the whole immersion time investigated. The TiC addition developed finer matrix structure, the formation of Cr-rich carbides and high dislocation density around the TiC particles before corrosion, which results in an increasing corrosion rate and preferential pitting attack at the steel matrix/TiC interface. Although the corrosion resistance of 2Cr13 stainless steel is sharply decreased due to TiC addition, it is significantly improved after the ESR process. This is attributed to the more uniform distribution and smaller size of TiC particles, the increase of value of χ in TiCχ and the elimination of the porosity in TiC particle-reinforced 2Cr13 stainless steel after the ESR process.

WC-Cr3C2 cermet coating on carbon steel was fabricated by laser controlled reactive synthesis and exhibited the metallurgical bonding at the interface between coating and substrate. The microstructure and wear properties of laser-clad WC-Cr3C2 Cermet Coating on steel substrate have been investaged by means of scaning eletron microscopy (SEM), X-ray diffraction (XRD), microhardness testing and wear testing. Experimental results show that the coating has a very good thermal resistance and high bonding strength due to Ni addition, which decreases stress concentration at the interface and increases the bonding strength due to better wettability. The coating shows superior hardness and wear resistance. In the same wear conditions, the wear resistance of the coating is 4 times than that of steel substrate.

TiC particle-reinforced 304 stainless steels were prepared using a new developed in situ technology and exhibited the uniform distribution of TiC particles in the matrix. The oxidation behavior of 304SS–2TiC and 304SS–6TiC (all in weight percentage) was compared with that of 304SS at 850 °C in air for 96 h using thermogravimetry analysis. For 304SS, the rate of weight gain was very slow initially, but accelerated suddenly to a very high level, forming breakaway oxidation. The addition of TiC particles to 304SS resulted in no breakaway oxidation and maintained a low oxidation rate in the whole reaction time investigated. Examination of oxide scale morphology and cross-section analysis by scanning electron microscopy and optical microscopy showed a significant scale spallation and a deep oxide penetration in the case of 304SS, but a rather continuous, dense and adherent oxide layer formed on the surface of TiC particle-reinforced alloys. XRD analysis revealed the presence of Cr 2 O 3 together with spinel-type oxides in the oxide scale. For TiC-containing alloys, fine TiO 2 was also found on the surface and the amount of this oxide increased with TiC addition. The TiC addition developed finer matrix structure before oxidation, which accelerates chromium diffusion. As a result, scale adherence was improved and oxidation resistance was increased.

The electroslag remelting (ESR) layer reinforced by TiC particles was obtained by electroslag remelting. The microstructure and wear properties of the ESR layer were studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and wear test. The results indicate that TiC particles are synthesized by self-propagating high-temperature synthesis (SHS) reaction during the electroslag remelting process. The size of TiC particles is in the range of 1–10 μm, and the distribution of TiC particles is uniform, from outside to inside of the ESR layer, and the volume fraction and the size of TiC particles decrease gradually. Molten iron and slag flow into porosity due to the SHS process leading to rapid densification and the elimination of porosity in the ESR layer during the ESR process. TiC particles enhance the wear resistance of the ESR layer, whereas CaF2 can improve the high temperature lubricating property of the ESR layer.

TiC particles have been synthesized in common straight steels with three different carbon contents by in situ reaction during melting process. Experimental results show that the distribution of TiC particles in the steels containing 0.55 mass%C and 0.8 mass%C is uniform, however, slight segregation of TiC particles has been observed in the steel containing 1.4 mass%C. With the formation of TiC more ferrite precipitates from the steel with 0.55 mass%C, while the TiC formation inhibits the precipitation of secondary cementite in the steel containing 1.4 wt%C. In the present investigation a proper technique of heat treatment has been designed, after which good mechanical properties as well as high wear resistance have been obtained from the steel with TiC additions. However the effect of TiC addition on wear resistance is weakened with the increase of carbon concentration. [doi:10.2320/matertrans.47.2393]