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A novel Fe-Cr-B-C-Al-Si-Mn composite coating was designed and synthesized on 2Cr13 steel substrate using laser cladding technique in this study. The microstructure evolution, microhardness and wear resistance of the composite coating were investigated. The results showed that the microstructure of the coating was mainly composed of α-(Fe,Cr,Al) martensite, retained γ-Fe, and the eutectic comprised of CrFeB, M3(C,B)2, M2(B,C) and M23(C,B)6. The average microhardness of the coating (742.1 HV0.5) was 3.95 times compared with the 2Cr13 steel substrate, and the wear resistance was enhanced by 12.5 times compared with the 2Cr13 steel substrate. The wear mechanisms were dominated by abrasive wear and oxidative wear.

An automatic well test interpretation method for radial composite reservoirs based on convolutional neural network (CNN) is proposed, and its effectiveness and accuracy are verified by actual field data. In this paper, based on the data transformed by logarithm function and the loss function of mean square error (MSE), the optimal CNN is obtained by reducing the loss function to optimize the network with “dropout” method to avoid over fitting. The trained optimal network can be directly used to interpret the buildup or drawdown pressure data of the well in the radial composite reservoir, that is, the log-log plot of the given measured pressure variation and its derivative data are input into the network, the outputs are corresponding reservoir parameters (mobility ratio, storativity ratio, dimensionless composite radius, and dimensionless group characterizing well storage and skin effects), which realizes the automatic initial fitting of well test interpretation parameters. The method is verified with field measured data of Daqing Oilfield. The research shows that the method has high interpretation accuracy, and it is superior to the analytical method and the least square method.

Well test analysis is a crucial technique to monitor reservoir performance, which is based on the theory of seepage mechanics, through the study of well test data, to identify reservoir models and estimate reservoir parameters. Reservoir model recognition is the first and essential step of well test analysis. It is usually judged by professionals’ experience, which results in low efficiency and accuracy. This paper is devoted to applying convolutional neural network (CNN) to well test analysis and proposes a new intelligent reservoir model identification method. Eight reservoir models studied in this paper include homogenous reservoirs with different outer boundaries such as infinite acting boundary, circular, single, angular, channel, U-shaped and rectangular sealing fault boundaries, and a radial composite reservoir with infinite acting boundary. Well testing data used in this paper, including actual field data and theoretical data, are generated by analytical solutions. To improve the classification accuracy of actual field data, noise processing was carried out on the data before training. The CNN that is most suitable for model recognition has been obtained through trial-and-error procedures. The availability of proposed CNN is proved with actual field cases of Daqing oil field, China. The method realizes the automatic identification of reservoir model with the total classification accuracy (TCA) of test data set of 98.68% and 95.18% for original data and noisy data, respectively.

Traditional anti-vibration hammer heads are mainly manufactured by gravity casting technology, which has many internal defects and limited mechanical properties, which cannot meet the technical requirements for higher-strength anti-vibration hammers in the construction of UHV transmission lines. Die forging is an advanced material forming process for producing low defect and high strength anti-vibration hammer. However, the process parameters should be strictly controlled to realize the complete filling of forgings and reduce the damage of forgings and dies.In this paper, the die forging process of the FDN type anti-vibration hammer head was simulated by using Deform-3D software platform, and the optimal forging process parameters were proposed as follows: the diameter of the blank is 65mm, the length of the blank is 184mm, the pressing speed of the upper die is 200mm/s, and the preheating temperature range of the blank is 800?∼1000?. The mechanical properties of the anti-vibration hammer after process optimization met the requirements of the corresponding strength grade products.

Knowledge of the mechanical properties of human skin has essential applications in cosmetic, dermatology and surgical fields. In this study, a hybrid experimental–numerical method was developed to characterize the human skin mechanical properties in vivo. An indentation experiment was physically conducted and simulated by finite element (FE) analysis. In the physical experiment, an indenter made of transparent glass was adopted so that the elliptical eccentricity in the contact area between skin and indenter could be monitored in real-time. In FE simulation, the dermis and subcutaneous tissue were modeled as anisotropic hyperelastic material and isotropic elastic material, respectively. By fitting the FE results to the experimental data, the three-dimensional (3D) mechanical properties of skin, including the dermis and subcutaneous tissue were determined. Furthermore, to demonstrate the ineffectiveness of the hybrid experimental–numerical method, a sensitivity analysis was conducted. In this sensitivity analysis, it is shown that the different mechanical parameters have a different contribution to the final FE result. Finally, the effect of subcutaneous tissue for in vivo skin indentation measurement was also evaluated.

In vivo characterization of facial soft tissue is of great significance for facial plastic surgery, animation and dermatology. This paper presents an in vivo experimental method to characterize the macroscopic mechanical properties of facial soft tissue. In this method, a bi-layer material (BLM) model is established with the skeleton as the substrate under the facial soft tissue and the relationship between the mechanical properties of soft tissue and force–displacement curve is obtained. A novel indentation apparatus is also developed to experimentally measure the force-displacement curve of the facial soft tissue in vivo. Using the apparatus, experiments were conducted on artificial skins to verify the theoretical model. Experiments on facial soft tissue were finally conducted on four volunteers to obtain Young’s moduli at five facial locations using an optimal indenter whose radius is determined by the verification experiment. Our experiment results indicate that a slight difference is observed in Young’s moduli of facial soft tissue among different volunteers and indentation location. At locations of the left-hand cheek near the lips (NE) and center of the left-hand jaw (CJ), Young’s moduli [Formula: see text] are relatively large ranging from 2.653[Formula: see text]kPa to 4.437[Formula: see text]kPa. Nevertheless, at other locations of the center of the cheek (CC), left-hand zygomatic region (ZYG) and left-hand cheek near the lips (NL), the contact forces are smaller, and Young’s moduli [Formula: see text] are between 1.649[Formula: see text]kPa and 3.395[Formula: see text]kPa.

The well testing technique is an important tool in estimating well and reservoir characteristics, such as permeability, skin factor and so on. For a long time, researchers have been searching for automatic well testing interpretation tools, but the results are disappointing. This paper proposes using convolutional neural network (CNN) as an automatic well test interpretation approach for infinite acting reservoirs. The CNN takes pressure change and pressure derivative data of the log-log plot for inputs. The wellbore storage coefficient, skin factor and reservoir permeability are redefined into a dimensionless group C D e 2 S as the output of the CNN. In this method, the best trained CNN structure is obtained by minimizing mean square error (MSE) and mean relative error (MRE). This new method is tested for its effectiveness and accuracy in Daqing oil field, China. It demonstrates that, for wells in infinite reservoir, CNN could be an effective automatic well test interpretation technique. CNN also shows the potential for more complicated scenarios.

This paper is concerned with the development of high-order weighted compact schemes based on linear central compact schemes (Liu et al., 2013). For the purpose of capturing strong discontinuities, the high-order upwind weighted nonlinear interpolations are combined with the central compact schemes and cell-centered compact schemes to achieve two different weighted compact schemes, called the CCSSR-W and CCCSSR-W schemes respectively. The CCSSR-W schemes are developed up to ninth order, and four different nonlinear weights of CCSSR-W schemes are investigated in detail. As an improvement of the CCSSR-HW scheme (Liu et al., 2015), the hybrid weighted nonlinear interpolation is substituted into the cell-centered compact scheme to obtain the CCCSSR-HW scheme. For all the proposed schemes, the flux vector splitting method is carried out by coupling with characteristic projections on the conservative fluxes. Through the systematic accuracy tests, spectral analysis and numerical experiments, the results demonstrate that the higher order CCSSR-W scheme is more accurate and effective than the lower order ones. The CCCSSR-W scheme has better accuracy and resolution than the original WENO scheme. The CCCSSR-HW scheme has higher resolution and lower dissipation than the CCSSR-HW scheme, and even better than the higher order CCSSR-W schemes.

Seepage characteristics of reservoir rocks are important factors affecting the effect of tight oil and gas production. Therefore the pore structure of tight sandstone from Dong 6 well in 4 block of the central Dzungaria Basin were studied by mercury injection experiment, and the seepage characteristics of tight sandstone were comprehensively studied by stress sensitivity experiment. The results show that: the pore throat distribution of the tight sandstone in the study area is not uniform, but the sorting property is good. The pore throat which promotes the permeability is mainly distributed near the threshold pressure of mercury injection experiment. The stress sensitivity of tight sandstone is affected by stress state and pore structure. Stress sensitivity is negatively correlated with confining pressure, and permeability loss is negatively correlated with pore throat radius.

This paper describes an efficient method for the synthesis of alpha-methylidene-gamma-amino acid esters from readily available aldehydes by using aminative umpolung strategy. Electrophilic aromatic aldehydes were converted to alpha-imino anions via amination with 2,2-diphenylglycine in methanol and subsequent decarboxylation in acetonitrile. The in situ generated a-imino anions displayed high activity in the reaction with Morita-Baylis-Hillman adducts in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as catalyst, to give a variety of substituted alpha-methylidene-gamma-amino acid esters in 54-96% yields with 3.2-7.1:1 diastereoselectivity. The resulting alpha-methylidene-gamma-amino acid esters can be efficiently converted into biologically important alpha-exo-methylidene-gamma-lactams under mild conditions.

A new type of novel chiral pyridoxamines 3a–g containing a side chain has been developed. The pyridoxamines displayed catalytic activity and promising enantioselectivity in biomimetic asymmetric transamination of α-keto acids, to give various α-amino acids in 47–90% yields with up to 87% ee’s under very mild conditions. An interesting effect of the side chain on enantioselectivity was observed in the reaction.

A new type of novel chiral pyridoxamines 3a–g containing a side chain has been developed. The pyridoxamines displayed catalytic activity and promising enantioselectivity in biomimetic asymmetric transamination of α-keto acids, to give various α-amino acids in 47–90% yields with up to 87% ee’s under very mild conditions. An interesting effect of the side chain on enantioselectivity was observed in the reaction.

Low dissolved oxygen (DO) is an energysaving condition in activated sludge process. To investigate the possible application of limited filamentous bulking (LFB) in sequencing batch reactor (SBR), two lab-scale SBRs were used to treat synthetic domestic wastewater and real municipal wastewater, respectively. The results showed that prolonging low DO aeration duration and setting pre-anoxic (anaerobic) phase were effective strategies to induce and inhibit filamentous sludge bulking, respectively. According to the sludge settleability, LFB could be maintained steadily by adjusting operation patterns. Filamentous bacteria content and sludge volume index (SVI) were likely correlated. SVI fluctuated dramatically within a few cycles when around 200 mL·g−1, where altering operation pattern could change sludge settleability in spite of the unstable status of activated sludge system. Energy consumption by aeration reduced under low DO LFB condition, whereas the nitrification performance deteriorated. However, short-cut nitrification and simultaneous nitrification denitrification (SND) were prone to take place under such conditions. When the cycle time kept constant, the anoxic (anaerobic) to aerobic time ratio was determining factor to the SND efficiency. Similarity keeping aerobic time as constant, the variation trends of SND efficiency and specific SND rate were uniform. SBR is a promising reactor to apply the LFB process in practice.

A class of high order central compact schemes with spectral-like resolution are designed for the computational aeroacousitcs (CAA). The schemes have the features of high order, high resolution, low dissipation and the ability to capture strong shock wave in flow field, which are perfect methods for computational aeroacoustics. Typical problems are solved through direct numerical simulation, including the merging process of two co-rotating Gaussian vortices, the interaction between an oblique shock wave and a shear layer and cavity flow. The mechanisms of noise generation are studied.

Deflection and crack width are the most important durability indexes, which play a pivotal role in the popularization and application of the Big Recycled Aggregate Self-Compacting Concrete technology. In this research, comparative study on the Big Recycled Aggregate Self-Compacting Concrete Beam and ordinary concrete beam were conducted by measuring the deflection and crack width index. The results show that both kind of concrete beams have almost equal mid-span deflection value and are slightly different in the maximum crack width. It indicates that the Big Recycled Aggregate Self-Compacting Concrete Beam will be a good substitute for ordinary concrete beam in some less critical structure projects.

In order to investigate the competition for carbon source between denitrification and phosphorus release processes, simultaneous phosphorus release and denitrification in sludge operated in anoxic, aerobic mode are investigated by varying the ratio of influent COD to nitrogenous compound concentration under anoxic condition using a lab-scale sequencing batch reactor (SBR). The results show that the nitrate reduction rate is nearly independent of the ratio of influent COD to nitrate under anoxic condition. More NO−x -N in the influent leads to less PO3−4 -P release during the feeding period. However, PO3−4 -P release proceeds at a low rate simultaneously with denitrification even when the influent NO−x -N concentration is as large as 20 mg·L−1 and its rate is increased obviously when NO−x -N is denitrified to a concentration lower than 0.5 mg·L−1. The variation of pH during anoxic period gives some information about the biochemical reactions of denitrification and PO3−4 -P release. When more nitrate is present in the influent, more acetate uptake in feeding period is used for direct microorganism growth.

This work describes the first Pd-catalyzed allylic alkylation of thioamides. Various thioamides were efficiently α-allylated in high yields and with excellent selectivity for monoallylation under mild reaction conditions. The process not only provides a facile method for the synthesis of functionalized thioamides, but also presents a useful transformation for synthetically important thioamides.

In situ prepared α-imino anions react with Morita—Baylis—Hillman adducts to form the title compounds (III) and (VI).

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor superfamily and have been implicated in chondrogenesis and neuronal differentiation. In order to examine the function of bone morphogenetic protein 2 (BMP‑2) on the differentiation of nitrergic enteric neurons in slow transit constipation (STC), the expression of BMP‑2 and neuronal nitric oxide synthase (nNOS) was investigated in the myenteric nerve plexus in STC and control tissues by immunohistochemical assays. The present study demonstrated that BMP‑2 and nNOS were expressed in the myenteric nerve plexus and their levels were differentially altered in the STC group and control group. In addition, the effect of BMP‑2 on primary myenteric neurons was investigated by measuring the neurite length. The results demonstrated that BMP‑2 regulated the differentiation of primary enteric neurons and increased the length of neurites compared with the control group. In addition, the effect of BMP‑2 on the expression of nNOS was also investigated in primary enteric neurons and the Smad1 signal transduction pathway by western blot analysis, reverse transcription quantitative polymerase chain reaction and immunofluorescence assay. The results suggested that BMP‑2 promoted the expression of nNOS in primary myenteric neurons and induced phosphorylation of Smad1. These data indicate a new role for BMP‑2 as an important transcriptional cofactor that regulates the differentiation of nitrergic enteric neurons through the Smad1 pathway. Intervention of BMP‑2 may be useful for the treatment of STC.

This new strategy allows the synthesis of various diamine products via formation of Schiff base lithium salts followed by decarboxylation.

Thioamides are unique and versatile synthetic building blocks with S, N, and α-C three adjacent nucleophile centers, however, they are rarely used as carbon nucleophiles for transition-metal-catalyzed C–C coupling reactions. This Letter describes the first Pd-catalyzed α-arylation of thioamides and demonstrated the feasibility of the application of thioamides in coupling chemistry. By the coupling process, a variety of α-arylated thioamides were prepared in moderate to good yields under mild reaction conditions, which provides an alternative way to access functionalized thioamides as well as a new synthetic transformation for thioamides. High chemoselectivity for thioamide over amide was observed in the reaction.

In this paper an aminative umpolung synthesis of aryl vicinal diamines from aldehydes and N-Ts imines is described. Electrophilic aromatic aldehydes were smoothly converted into delocalized 2-azaallylanions via condensation with 2,2-diphenylglycine in methanol and subsequent decarboxylation in THF and underwent further reaction with N-Ts imines to give a variety of 1,2-diamine derivatives in good yields with high syn/anti diastereoselectivity.

This work describes the first Pd-catalyzed allylic alkylation of thioamides. Various thioamides were efficiently α-allylated in high yields and with excellent selectivity for monoallylation under mild reaction conditions. The process not only provides a facile method for the synthesis of functionalized thioamides, but also presents a useful transformation for synthetically important thioamides.

In this paper, we design a class of linear compact schemes based on the cell-centered compact scheme of ((Lele, J Comput Phys 103:16–42, 1992). These schemes equate a weighted sum of the nodal derivatives of a smooth function to a weighted sum of the function on both the grid points and the cell-centers. Through systematic Fourier analysis and numerical tests, we observe that the schemes have good properties of high order, high resolution, and low dissipation. It is an ideal class of schemes for the simulation of multiscale problems such as aeroacoustics and turbulence.

The process is successful with various aryl bromides and phenyl iodide (IIa) and affords functionalized thioamide structures with moderate yields.

The solubility of cobalt oxide in silica-saturated iron silicate slags (1.16 to 10.00 wt pct) in equilibrium with cobalt-gold-iron alloys (1.10 to 6.52 wt pct cobalt) and oxygen pressures of 10−9 to 10−10 atm (1 atm = 1.013 x 105 Pa) has been investigated at 1573 K. The activity coefficient of cobalt oxide, γCoO, has been calculated relative to pure solid cobalt oxide as standard, namely, γCoO = 0.91 ± 0.09