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Triazine porous organic polymer thin film constructed using nanoparticle-polymer reticulation strategy exhibits high perm-selectivity and good anti-fouling/-bacterial property.

High cleanliness is a crucial factor determining the service performance of bearing steel. Considering the strong deoxidation ability of carbon under vacuum, vacuum carbon deoxidation was adopted in the cleanliness control of high nitrogen stainless bearing steel. In this paper, a mathematical model for vacuum carbon deoxidation during pressure/vacuum induction melting (PVIM) was proposed considering the occurrence of carbon–oxygen reaction at the free surface of molten pool and at the interface between CO bubbles and molten steel as well as crucible decomposition. The effect of electromagnetic stirring on the mass transfer of oxygen was analyzed using the finite element numerical method and the effect of CO bubbles on the deoxidation process was also considered. The influence of pressure, temperature and initial carbon content on deoxidization was studied and experimentally verified. The results indicated that the predicted variation of oxygen content in molten steel with time agreed well with the experimental results. Electromagnetic stirring effectively promoted the mass transfer of oxygen in molten steel and the carbon–oxygen reaction at free surface of molten pool was the main pathway for deoxidization. The pressure, temperature and initial carbon content influenced the vacuum carbon deoxidation process by affecting the carbon–oxygen reaction rate, crucible decomposition and mass transfer coefficient of oxygen. Finally, optimum melting parameters were recommended.

The existence of angular and hard AlN inclusions would seriously deteriorate the service life of high-nitrogen stainless bearing steels (HNSBSs). In this work, the formation mechanism of AlN inclusion in HNSBSs under as-cast, annealing and austenitizing states was systematically investigated by microstructure observation and thermodynamic, kinetic analyses. The results showed that the concentration product of Al and N could exceed the critical solubility of AlN inclusion at liquidus temperature with the Al content higher than 0.050 wt pct, which led to the formation of AlN inclusions about 1 to 5 μm (equivalent diameter) in liquid steel. Based on the ‘Clyne-Kurz’ model, AlN inclusion could form at the solidifying front due to the enrichment of N in the residual liquid steel with the Al content higher than 0.030 wt pct. Besides, the precipitation of Cr2N and the extremely low diffusion coefficient of Al in α phase restrained the precipitation of AlN during annealing at 1023 K. However, AlN and AlN-MnS composite inclusions less than 0.6 μm could precipitate during austenitizing at 1323 K with the Al content higher than 0.006 wt pct, which was the critical Al content to avoid AlN formation in HNSBSs after melting, solidification, and heat treatment processes.

Pecan cuttings are difficult for rooting. This study describes the pecan hardwood rooting process based on anatomic characteristics to understand root formation mechanisms of pecan cuttings. The expressed proteins of different periods during the adventitious rooting process of pecan seedling hardwood cuttings were identified and analyzed to evaluate the rooting mechanism. The expressed proteins of pecan cutting seedlings were also compared with other cultivar cuttings during the rooting period. Pecan seedling cuttings were developed at different air and substrate temperatures to induce root formation. Adventitious root formation of pecan hardwood cuttings was described, and the phloem at the base of the prepared cuttings was selected as the sample for the differential protein analysis. The results showed that adventitious root formation of pecan hardwood cuttings was the only product of callus differentiation, which originated from the cells of the cambium or vascular ray parenchyma. Such adventitious root primordia were developed from those calluses that formed the regenerative structure, and the expressed proteins during the adventitious rooting of pecan hardwood cutting were identified and analyzed by matrix-assisted laser desorption ionization–time of flight–mass spectrometry (MALDI-TOF-MS) to evaluate the rooting mechanism. Eight differentially expressed proteins were found in the rooting periods, and 15 differential proteins were found by comparing pecan cutting types, which were analyzed by peptide mass fingerprinting homology. The results show that the primordial cells were differentiated from the meristematic cells. Furthermore, the differentially expressed proteins contained energy metabolism proteins, adversity stress proteins, and signal transmission proteins. The energy metabolism-related proteins were adenosine triphosphate (ATP) synthase, photosynthesis-related proteins, and enolase. The adversity-stress proteins containing heat shock-related proteins and signal transmission proteins were mainly cytochrome enzymes and heme-binding proteins. Adventitious root formation of pecan cultivar hardwood cuttings was difficult. More trials should be performed from the potential aspects of high defensive protection and phloem morphologic structure.

The operation of blast furnace is considerably influenced by slag performance, particularly in BF hearth. Slag holdup in deadman has negative effects on hearth, such as sharp peripheral flow of hot...

Cytosine methylation plays important roles in regulating gene expression and modulating agronomic traits. In this study, the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) technique was used to study variation in cytosine methylation among seven pecan (Carya illinoinensis) cultivars at four developmental stages. In addition, phenotypic variations in the leaves of these seven cultivars were investigated. Using eight primer sets, 22,796 bands and 950 sites were detected in the pecan cultivars at four stages. Variation in cytosine methylation was observed among the pecan cultivars, with total methylation levels ranging from 51.18% to 56.58% and polymorphism rates of 82.29%, 81.73%, 78.64%, and 79.09% being recorded at the four stages. Sufficiently accompanying the polymorphism data, significant differences in phenotypic traits were also observed among the pecan cultivars, suggesting that cytosine methylation may be an important factor underlying phenotypic variation. Hypermethylation was the dominant type of methylation among the four types observed, and full methylation occurred at higher levels than did hemimethylation in the pecan genomes. Cluster analysis and principal coordinate analysis (PCoA) identified Dice coefficients ranging from 0.698 to 0.778, with an average coefficient of 0.735, and the variance contribution rates of the previous three principal coordinates were 19.6%, 19.0%, and 18.2%, respectively. Among the seven pecan cultivars, four groups were clearly classified based on a Dice coefficient of 0.75 and the previous three principal coordinates. Tracing dynamic changes in methylation status across stages revealed that methylation patterns changed at a larger proportion of CCGG sites from the 30% of final fruit-size (30%-FFS) stage to the 70%-FFS stage, with general decreases in the total methylation level, the rate of polymorphism, and specific sites being observed in each cultivar. These results demonstrated that the F-MSAP technique is a powerful tool for quantitatively detecting cytosine methylation in pecan genomes and provide a new perspective for studying many important life processes in pecan.

Using an environmentally friendly acid-alcohol system solution for electrochemical polishing of 3D printed titanium alloy, a typical U-I polarization curve was obtained, and explained the mechanism of electrochemical polishing. In this paper, the influence of electrochemical polishing factors (electrolyte temperature, polishing distance, and polishing time) on the surface roughness of Ti-6Al-4V (TC4) was studied, and optimized the process parameters to obtain a surface roughness of 0.3 μm (1 mm × 1 mm). Electrochemical polishing can reach the level of mechanical grinding and polishing, meeting the requirements for subsequent assembly and use.

Titanium removal in a basic oxygen furnace (BOF) converter process was simulated by an experiment in a 500-kg intermediate frequency induction furnace with top- and bottom-blowing functions, and the reaction mechanism of titanium oxidation was investigated. The results showed that the average end point mass percent of titanium in the hot metal was 0.008 2% and the rate of titanium removal was 71.3%. The rate of titanium removal decreased as the temperature of the hot metal increased, whereas it increased with the oxygen supply to the molten pool. The ratio between titanium and manganese is similar to that between titanium and silicon in the hot metal at the end point. However, the titanium content is not associated with carbon oxidation at the end point. The titanium distribution ratio between the slag and hot metal ranges from 0.6 to 1.6, and it increases with the (FeO) content in slag, but decreases as the temperature of the hot metal increases. The experimental results correspond with the theoretical analysis, which conclude that the titanium oxidation reaction is more likely to occur at lower temperatures.

Root systems of pecan trees are usually dominated by a single taproot with few lateral roots, which are commonly thought to inhibit successful transplanting. This study aimed to evaluate early growth and root/shoot development of pecan seedlings in response to taproot pruning. Taproots of ‘Shaoxing’ seedling pecan trees were mildly (1/3 of the total length of the radicle removed) and severely (2/3 of the total length of the radicle removed) pruned at different seedling development stages shortly after germination. At the end of the first growing season, top growth was measured and then trees were uprooted so that root system regrowth could be evaluated. The results showed that root pruning had no impact on increases in stem height or stem diameter. However, pruning the taproot could stimulate primary growth in taproot branches. Root weight and the number of taproot branches per tree increased with decreasing taproot length. This study indicated that severe root pruning when three to five leaves had emerged resulted in root systems with more taproot branches and the greatest root dry weight after one growth season, which may increase survival and reduce transplanting shock.

This paper proposes a new non-intrusive hybrid interval method using derivative information for the dynamic response analysis of nonlinear systems with uncertain-but-bounded parameters and/or initial conditions. This method provides tighter solution ranges compared to the existing polynomial approximation interval methods. Interval arithmetic using the Chebyshev basis and interval arithmetic using the general form modified affine basis for polynomials are developed to obtain tighter bounds for interval computation. To further reduce the overestimation caused by the “wrapping effect” of interval arithmetic, the derivative information of dynamic responses is used to achieve exact solutions when the dynamic responses are monotonic with respect to all the uncertain variables. Finally, two typical numerical examples with nonlinearity are applied to demonstrate the effectiveness of the proposed hybrid interval method, in particular, its ability to effectively control the overestimation for specific timepoints.

Scion wood of ‘Caddo’ and ‘Desirable’ pecan (Carya illinoinensis) was grafted onto the epicotyl of 1-month-old, open-pollinated ‘Shaoxing’ pecan seedlings for evaluation as a grafting technique to reduce the time to produce grafted trees. The results showed that seedlings grafted with “base scions” had higher survival than those grafted with “terminal scions” for both ‘Caddo’ and ‘Desirable’. Also, grafting with paraffinic tape could achieve greater success rate than that with medical tape. The most ideal time to perform this grafting was late April in Nanjing, China, when pecan seedlings were about 35 days old. This study demonstrated that the technique yielded successful epicotyl grafting of >70%, and it could thus be applied in practice.

This paper proposes a new non-intrusive trigonometric polynomial approximation interval method for the dynamic response analysis of nonlinear systems with uncertain-but-bounded parameters and/or initial conditions. This method provides tighter solution ranges compared to the existing approximation interval methods. We consider trigonometric approximation polynomials of three types: both cosine and sine functions, the sine function, and the cosine function. Thus, special interval arithmetic for trigonometric function without overestimation can be used to obtain interval results. The interval method using trigonometric approximation polynomials with a cosine functional form exhibits better performance than the existing Taylor interval method and Chebyshev interval method. Finally, two typical numerical examples with nonlinearity are applied to demonstrate the effectiveness of the proposed method.

Heavy duty machine tool has some special points, such as large size, complex structure, long cycle at Installation and commissioning, high requirements assembly processes and so on. Therefore, this paper established a mathematical model to transform the origin parts of the gantry machining center into assembly special form and creates a software as a plug-in for Solidworks based on it, proposes an easy but very practical assembly method based on Multi-body system under virtual environment. This method can calculate assembly deviation caused by manufacturing tolerance very quickly, and bring the sensitivity information clearly. Assembly deviation sensitivity and assembly method proposed in this paper can provide a way for the virtual assembly of heavy-duty CNC machine tools, Thus provide an important theoretical basis to improve the performance of the machine

Geometric mobiles is a new kinetic art which become a new technique combined with basic science and modern art. Geometric mobiles design and calculation by mechanics and mathematics in order to have a slowly and elegant movements. An innovative and efficient design method is first established based on virtual technology and polymorphs small cell centroid point analytical rule. The method reveals the intrinsic relationship between Geometric mobiles and mathematics & mechanics modeling, provides the mathematics foundation for art works innovative and next research.

Alkali plays a significant role in the formation of brittle layer of carbon brick in the blast furnace hearth. The brittle layer in a commercial blast furnace hearth was investigated. Large amounts of potassium compounds were found in the brittle layer. Subsequently, the carbon bricks which reacted with potassium in the simulation of blast furnace hearth under different contents of potassium in the brick (0.25, 0.5, 1.0 and 2.0 wt.%) during various reaction times (0.5, 1, 2 and 4 h) were experimentally studied. Finally, the formation mechanism of the brittle layer in carbon brick was clarified. The investigation results show that a large number of cracks are present in the brittle layer. The average potassium content in the brittle layer is 1 wt.%. According to the experimental results, cracks in the carbon brick can be formed by the attack of potassium. The reason for the formation of the brittle layer in the carbon brick is that the liquid potassium permeates into the carbon brick through the pores and cracks, and then reacts with SiO2 and Al2O3 in CO atmosphere. The generated potassium compounds nepheline and leucite lead to the volume expansion and the damage of the carbon brick.