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The application of the bionematicides derived from microorganisms and their secondary metabolites represents a promising strategy for managing root-knot nematodes. In this study, a nematicidal compound, cis-3-indoleacrylic acid, was isolated from Streptomyces youssoufiensisYMF3.862. This compound caused Meloidogyne incognitajuveniles to have swollen bodies with apparent cracks on the cuticle surface. The LC50value of cis-3-indoleacrylic acid against juveniles was 16.31 μg/mL 24 h of post-treatment. Cis-3-indoleacrylic acid at 20 μg/mL significantly inhibited V-ATPase expression and remarkably decreased enzyme activity by 84.41%. As an inhibitor of V-ATPase, cis-3-indoleacrylic acid caused significant H+accumulation in nematode bodies, resulting in lower intracellular pH values and higher extracellular pH values of M. incognita. Application of 50 μg/mL cis-3-indoleacrylic acid generated a 71.06% control efficiency against M. incognitaon tomatoes. The combination results of this study indicated that cis-3-indoleacrylic acid can be developed as a natural nematicide for controlling M. incognita.

The abilities to describe the fracture behavior and calibrate the relevant parameters are essential factors in evaluating ductile fracture criteria of titanium alloys. In this study, 14 different shapes and notched specimens were designed for uniaxial tensile and compression experiments to characterize their ductile fracture behaviors. Based on the analysis of plastic behavior and fracture mechanism, a mixed hardening model, the Von Mises yield criterion and DF2016 fracture criterion were established, respectively. A parameter-identification method based on machine learning was proposed to improve the parameter calibration of the ductile fracture model. The results showed that the DF2016 fracture model accurately predicted the damage initiation and fracture process of the forged TC4 titanium alloy during the forming process. The machine-learning method avoided extracting different stress state evolution processes and large amounts of data from the numerical model of the calibrated specimens. The combination of the semi-coupled fracture model and parameter-identification method provides a new method that alleviates the difficulty of balancing parameter calibration and the ability to characterize the ductile fracture criteria.

A novel expandable conductor was designed and applied in deep-water drilling to improve the vertical and lateral bearing capacity with a significant reduction of conductor jetting depth and soaking time. The vertical and lateral bearing capability of expandable conductors was depicted based on the ultimate subgrade reaction method and pile foundation bearing theory. The load-bearing characteristics of a laboratory-scale expandable conductor were analyzed through laboratory experiments. The serial simulation experiments are accomplished to study the bearing characteristics (vertical ultimate bearing capacity, lateral soil pressure, and lateral displacement) during the conductor soaking process. The laboratory experimental results show that the larger the length and thickness of expandable materials are, the higher the bearing capacity of the wellhead will be. During the conductor soaking process, the soil pressure around the three expandable conductors increases faster, strings representing a stronger squeezing effect and resulting in higher vertical bearing capacity. Furthermore, the lateral displacement of novel expandable conductor is smaller than that of the conventional conductor. All the advantages mentioned above contributed to the reduction of conductor’s jetting depth and soaking time. Lastly, the application workflow of a novel expandable deep-water drilling conductor was established and the autonomous expandable conductor was successfully applied in the South China Sea with a significant reduction of conductor’s jetting depth and soaking time. According to the soil properties and designed installation depth of the surface conductor, the arrangement of expandable materials should be designed reasonably to meet the safety condition and reduce the construction cost of the subsea wellhead.

The hot deformation behavior of TA32 titanium alloy in the temperature range of 650–850 °C and strain rate range of 0.0001–0.1 s−1was studied by isothermal hot tensile tests conducted on an electronic universal testing machine equipped with an environmental chamber. The effects of temperature and strain rate on the flow stress of TA32 were investigated. Moreover, a back-propagation artificial neural network (BP-ANN) model was developed to predict the flow stress at elevated temperatures and three-dimensional (3-d) thermal processing maps. The results show that the three-layer BP-ANN model can precisely predict the flow stress as the correlation coefficient reaches 0.99365 and the mean relative error is 1.15621%. The 3-d thermal processing maps demonstrate that the lower strain rate, higher temperature, and larger strain lead to higher power dissipation efficiency and better formability. And it shows a flow instability tendency at lower temperatures and higher strain rates. Based on the 3-d thermal processing maps and microstructure analysis, the optimized temperature range and strain rate range for TA32 hot forming were 770–830 °C and 0.0001–0.00015 s−1.

To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensisand holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.

The hot flow behaviors, microstructure evolution and fractographs were studied to optimize the hot forming process of the TA32 titanium alloy thin-walled part. A set of microstructure-based constitutive equations were developed based on the experimental data, which described the relationships among the hot flow stresses and the evolution of phase volume fraction, dislocation density, grain size and damage. The constitutive model was imported into ABAQUS 6.14 to simulate the hot forming process for a typical thin-walled part. The effective strain, dislocation density and damage distribution as well as forming defects of formed parts under different process parameters were predicted. A qualified part without wrinkling and fracture defects was produced at a loading speed of 5 mm/s at 800 °C by the modified blank shape, where the maximum damage value was only 18.3%. The accuracy of constitutive model and finite element (FE) simulation was verified by the microhardness tests, which indicates that the FE model based on physical internal-state variables can well optimize the hot forming process of TA32 titanium alloy complex parts.

The process of transient liquid phase bonding to form intermetallic compound solder joints can effectively achieve 3D chip stack interconnection. However, there are a large number of void defects in IMC solder joints due to the rapid reaction between elements, which reduces the reliability of the chip stack interconnection. In this study, the interfacial reaction, shear behavior and microhardness of CuSn TLP bonding joints were investigated by adding 0.5 wt% CuZnAl powder into the pure Sn interconnect solder. Adding CuZnAl powder can remarkably retard the growth of intermetallic compound and voids in the bonding joints, which is attributed to the fact that CuZnAl powder can reduce the concentration gradient of Cu in the interface region. Compared with the Cu-Sn-Cu bonding joints, the shear strength of composite bonding joints was increased by 12%–19.7%, and the microhardness of composite bonding joints was also improved.

The deformation mechanism of C5191 phosphor bronze sheet under ultra-high-speed blanking was investigated. By virtue of a DOBBY-OMEGA F1 ultra-high-speed press, the ultra-high-speed blanking test was conducted on C5191 phosphor bronze sheets with a thickness of 0.12 mm at 3000 strokes per minute. The microstructures of the blanked edges were characterized and analyzed separately by electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that grains in the blanked edges are stretched along the blanking direction. Strong {001}〈100〉 cube textures (maximum pole densities of 9 and 12, respectively) and secondarily strong {011}〈011〉 textures (maximum pole densities of 4 and 7, respectively) are formed in local zones. Additionally, deformation twins are found in the shear zone of the blanked edges which are rotated and coarsened due to the blanking-induced extrusion and local thermal effect which can further form into sub-grains with clear and high-angle boundaries. The C5191 phosphor bronze sheet is subjected to adiabatic shear during ultra-high-speed blanking, accompanied with dynamic recrystallization.

Stroke is a common cause of death and disability. Allisartan isoproxil (ALL) is a new angiotensin II receptor blocker and a new antihypertensive drug discovered and developed in China. In the present study we investigated the therapeutic effects of ALL in stroke-prone renovascular hypertensive rats (RHR-SP) and the underlying mechanisms. The model rats were generated via two-kidney two-clip (2K2C) surgery, which led to 100% of hypertension, 100% of cerebrovascular damage as well as 100% of mortality 1 year after the surgery. Administration of ALL (30 mg · kg−1· d−1in diet, for 55 weeks) significantly decreased stroke-related death and prolonged lifespan in RHR-SP, but the survival ALL-treated RHR-SP remained of hypertension and cardiovascular hypertrophy compared with sham-operated normal controls. In addition to cardiac, and aortic protection, ALL treatment for 10 or 12 weeks significantly reduced cerebrovascular damage incidence and scoring, along with a steady reduction of blood pressure (BP) in RHR-SP. Meanwhile, it significantly decreased serum aldosterone and malondialdehyde levels and cerebral NAD(P)H oxidase expressions in RHR-SP. We conducted 24 h continuous BP recording in conscious freely moving RHR-SP, and found that a single intragastric administration of ALL produced a long hypotensive effect lasting for at least 12 h on systolic BP. Taken together, our results in RHR-SP demonstrate that ALL can be used for stroke prevention via BP reduction and organ protection, with the molecular mechanisms related to inhibition of angiotensin–aldosterone system and oxidative stress. This study also provides a valuable scoring for evaluation of cerebrovascular damage and drug efficacy.

Metrnl is a newly identified secreted protein highly expressed in the intestinal epithelium. This study aimed to explore the role and mechanism of intestinal epithelial Metrnl in ulcerative colitis. Metrnl−/−(intestinal epithelial cell-specific Metrnl knockout) mice did not display any phenotypes of colitis under basal conditions. However, under administration of 3% dextran sodium sulfate (DSS) drinking water, colitis was more severe in Metrnl−/−mice than in WT mice, as indicated by comparisons of body weight loss, the presence of occult or gross blood per rectum, stool consistency, shrinkage in the colon, intestinal damage, and serum levels of inflammatory factors. DSS-induced colitis activated autophagy in the colon. This activation was partially inhibited by intestinal epithelial Metrnl deficiency, as indicated by a decrease in Beclin-1 and LC3-II/I and an increase in p62 in DSS-treated Metrnl−/−mice compared with WT mice. These phenomena were further confirmed by observation of autophagosomes and immunofluorescence staining for LC3 in epithelial cells. The autophagy-related AMPK-mTOR-p70S6K pathway was also activated in DSS-induced colitis, and this pathway was partially blocked by intestinal epithelial Metrnl deficiency, as indicated by a decrease in AMPK phosphorylation and an increase in mTOR and p70S6K phosphorylation in DSS-treated Metrnl−/−mice compared with WT mice. Therefore, Metrnl deficiency deteriorated ulcerative colitis at least partially through inhibition of autophagy via the AMPK-mTOR-p70S6K pathway, suggesting that Metrnl is a therapeutic target for ulcerative colitis.

Hornworts, liverworts and mosses are three early diverging clades of land plants, and together comprise the bryophytes. Here, we report the draft genome sequence of the hornwort Anthoceros angustus. Phylogenomic inferences confirm the monophyly of bryophytes, with hornworts sister to liverworts and mosses. The simple morphology of hornworts correlates with low genetic redundancy in plant body plan, while the basic transcriptional regulation toolkit for plant development has already been established in this early land plant lineage. Although the Anthocerosgenome is small and characterized by minimal redundancy, expansions are observed in gene families related to RNA editing, UV protection and desiccation tolerance. The genome of A. angustusbears the signatures of horizontally transferred genes from bacteria and fungi, in particular of genes operating in stress-response and metabolic pathways. Our study provides insight into the unique features of hornworts and their molecular adaptations to live on land.

Objective To investigate the application of mind mapping-based health education in extended care for children with caries.Methods This was a prospective study of 159 eligible children with caries. Participants were randomly assigned to an observation group and a control group, and received extended health education and guidance. Patients in the observation group received health education with mind mapping. In the third month after the first visit, a questionnaire survey was conducted to assess knowledge of extended caries diagnosis and treatment in children and their parents. Children also underwent a bacterial plaque test.Results Caries knowledge was significantly greater in the observation group than in the control group. There was no significant between-group difference in debris index on the bacterial plaque test. The observation group had a significantly greater number of follow-up visits in 12 months than the control group.Conclusions Mind mapping was effective in the implementation of extended care. Mind mapping information was more accessible to children and their parents, increasing their compliance with health education. Thus, mind mapping is an appropriate health education tool for use in extended care for children with caries.

In Underwater Acoustic Sensor Network (UASN) based fog systems, the monitored messages are transmitted from the sensors deployed under the water to the surface sinks, which act as the fog nodes, for further processing. To ensure the reliability of the data transmission process, effective routing algorithms are necessary to reduce the packet loss rate as well as the transmission delay caused by potential traffic burst and hotspots. For this reason, a reliable routing protocol against hotspots and burst (RRAHB) is proposed in this paper. The fuzzy decision algorithm (FDA) for nodes path selecting is designed firstly. When the node chooses the next hop, the candidate nodes are evaluated by FDA. It eliminates the subjectivity of expert scoring and ensure fairness and effectiveness of the evaluated scores. But, FDA cannot solve the problems of hotspots and the load unbalance effectively, which are two important factors that cause data packets loss. Based on FDA, the random selection and hotspots avoidance mechanism are presented. The probability of the hotspots can be reduced by the random selection, and the hotspots effect is eliminated by the hotspots avoidance mechanism. In addition, in order to guarantee the network load balance, a priority-based traffic scheduling mechanism (PTSM) is proposed. It solves the traffic surge problem caused by emergency events and reduces the possibility of packets loss. The simulation results verify the effectiveness of RRAHB in the network with dynamic topology. Compared with the traditional routing algorithm, it has great advantages in improving network reliability and enhancing network performance.

As a promising new molecular imaging technique, mass spectrometry imaging (MSI) has attracted more and more attention in the field of biomedicine. A method of air flow assisted ionization-ultra high resolution mass spectrometry-based mass spectrometric imaging (AFAI-MSI) was developed to profile endogenous metabolites in rat kidney tissue in this study. Rat kidneys were collected and cut into frozen tissue sections, and then were analyzed on an AFAI-MSI system operated in positive ion mode using acetonitrile- isopropanol-water (4:4:2, V/V, 5 μL min−1) as spray solvent, nitrogen gas as spray gas (0.6 MPa) and air as assisting gas (45 L min−1). The mass range and resolution were set to be 70–1000 Da and 70000, respectively. As a result, a total of 38 metabolites, ranging from 103to 107in signal strength and belonging to different metabolite types, including organic amines, sugars, vitamins, peptides, neurotransmitters, organic acids, phospholipids, sphingolipids, glycerides, and cholesterol esters, were identified and imaged to characterize their tissue-specific distribution in kidney tissues. Some metabolites, such as choline, acetycholine, betaine, phosphocholine, and glycerolphosphocholin were found to have distinct distribution along the cortex-medulla axis, which may be involved in the formation of osmotic pressure gradient in the kidney. The proposed ultra high resolution mass spectrometry based AFAI-MSI method can work without sample pretreatment, showing high sensitivity and wide metabolite coverage, and is expected to provide a new analytical approach in the research of in situcharacterization and metabolic regulation mechanism of endogenous metabolites in kidney.

MicroRNAs (miRNAs) have been reported to be associated with cancer progression and carcinogenesis. They are small, highly conserved, noncoding RNA molecules consisting of 19–25 nucleotides. By binding to complementary binding sites within the 3′-untranslated region of target mRNAs, miRNAs inhibit the translation of mRNAs or promote their degradation. miRNAs play critical roles in cancer initiation and development by functioning either as oncogenes or as tumor suppressors. Similarly, several studies have shown that miRNAs are involved in regulating various biological processes, including apoptosis, proliferation, cellular differentiation, signal transduction, and carcinogenesis. Among miRNAs, one that may be of particular interest in cancer biology is miR-449a, which has been reported to inhibit tumor growth, invasion, and metastasis, and to promote apoptosis and differentiation through the transforming growth factor-β activated kinase 1, NOTCH, nuclear factor-κB/P65/vascular endothelial growth factor, retinoblastoma-E2F, mitogen-activated protein kinase signaling pathways, WNT–β-catenin signaling, tumor protein P53, and androgen receptor signaling pathways. The miR-449 cluster is located in the second intron of CDC20B on chromosome 5q11.2, a region that has been identified as a susceptibility locus in cancer, and the abnormal expression of miR-449a may be related to the occurrence and development of tumors. As one example, miR-449a has been reported to be involved in the development of carcinoma and may be a potential prognostic indicator. On the basis of the putative pathogenetic relationships between cancer and miR-449a, we consider that miR-449a has the potential to serve as a therapeutic agent for the treatment of some types of cancer. In this review, the role of miR-449a in tumorigenesis and its mechanism of action are explored. Furthermore, its potential as a therapeutic agent in cancer treatment is considered.

Density functional theory (DFT) calculations of the structures and the Cu2+gfactors (gx, gyand gz) and hyperfine coupling tensor A(Ax, Ayand Az) were performed for the paddle-wheel (PW)-type binuclear copper(II) complex {Cu2(μ2-O2CCH3)4}(OCNH2CH3) powder and single crystal. Calculations were carried out with the ORCA software using the functionals BHandHlyp, B3P86 and B3LYP with five different basis sets: 6-311g, 6-311g(d,p), VTZ, def-2 and def2-TZVP. Results were tested by the MPAD analysis to find the most suitable functional and basis sets. The electronic structure and covalency between copper and oxygen were investigated by the electron localisation function and the localised orbital locator as well as the Mayer bond order for the [CuO5] group. The optical spectra were theoretically calculated by the time-dependent DFT module and plotted by the Multiwfn program for the [CuO5] group and reasonably associated with the local structure in the vicinity of the central ion copper. In addition, the interactions between the OCNH2CH3, NH3and H2O molecules and the uncoordinated PW copper(II) complex were studied, and the corresponding adsorption energies, the frequency shifts with respect to the free molecules and the changes of the Cu–Cu distances were calculated and compared with the relevant systems.

The as-cast microstructures and mechanical properties of Al-Si-Mg-Cu-Ti alloys with and without Sc were investigated by metallographic microscope, field emission scanning electron microscope, energy spectrum analysis, transmission electron microscope and universal testing machine. The result shows that adding 0.20wt.% Sc into the casting alloy can refine the grain, change the growth morphology from dendrite to fine equiaxed grain, and the morphology of eutectic Si by rough laminar structure into fine fibrous. The tensile strength of alloy with 0.20wt.% Sc is up to 304.4 MPa after T6 heat treated, which is close to that of 6061 forging aluminum alloy.

The spin Hamiltonian parameters and local structures are theoretically studied for Cu2+-doped alkaline earth lead zinc phosphate (RPPZ, R=Mg, Ca, Sr, and Ba) glasses based on the high-order perturbation calculations for a tetragonally elongated octahedral 3d9cluster. The relative elongation ratios are found to be ρ≈3.2%, 4.4%, 4.6%, and 3.3% for R=Mg, Ca, Sr, and Ba, respectively, because of the Jahn-Teller effect. The whole decreasing crystal-field strength Dqand orbital reduction factor kfrom Mg to Sr are ascribed to the weakening electrostatic coulombic interactions and the increasing probability of productivity of nonbridge oxygen (and hence increasing Cu2+–O2−electron cloud admixtures) under PbO addition, respectively, with increasing alkali earth ionic radius. The anomalies (the largest Dqand the next highest kamong the systems) for R=Ba are attributed to the cross linkage of this large cation in the network. The overall increasing order (Mg≤Ba

Aim:MicroRNAs play pivotal roles in regulation of both innate and adaptive immune responses. In the present study, we investigated the effects of microRNA-124 (miR-124) on production of the pro-inflammatory cytokine TNF-α in lipopolysaccharide (LPS)-treated mouse macrophages.Methods:Mouse macrophage cell line RAW264.7 was stimulated with LPS (100 ng/mL). The levels of miR-124 and TNF-α mRNA were evaluated using q-PCR. ELISA and Western blotting were used to detect TNF-α protein level in cell supernatants and cells, respectively. 3′-UTR luciferase reporter assays were used to analyze the targets of miR-124. For in vivo experiments, mice were injected with LPS (30 mg/kg, ip).Results:LPS stimulation significantly increased the mRNA level of miR-124 in RAW264.7 macrophages in vitro and mice in vivo. In RAW264.7 macrophages, knockdown of miR-124 with miR-124 inhibitor dose-dependently increased LPS-stimulated production of TNF-α protein and prolonged the half-life of TNF-α protein, but did not change TNF-α mRNA levels, whereas overexpression of miR-124 with miR-124 mimic produced the opposite effects. Furthermore, miR-124 was found to directly target two components of deubiquitinating enzymes: ubiquitin-specific proteases (USP) 2 and 14. Knockdown of USP2 or USP14 accelerated protein degradation of TNF-α, and abolished the effect of miR-124 on TNF-α protein stability.Conclusion:miR-124, targeting USP2 and USP14, negatively regulates LPS-induced TNF-α production in mouse macrophages, suggesting miR-124 as a new therapeutic target in inflammation-related diseases.

The deformation behavior and mechanism of Ti2AlNb-based alloy were experimentally investigated at elevated temperatures. Firstly, the stress–strain relationships at different temperatures and strain rates were investigated via uniaxial tensile testing. Then, formability data, as determined by examining the deep drawing and bending abilities, were obtained through limiting draw ratio (LDR) and bending tests. Finally, metallographic experiments and fracture morphology investigations were conducted to examine the thermal deformation mechanism of the alloy. The results showed that as the temperature increased, the total elongation increased from 13.58% to 97.82% and the yield strength decreased from 788 to 80 MPa over the temperature range from 750 to 950 °C at a strain rate 0.001 s−1. When the temperature reached 950 °C, the strain rate was found to have a great influence on the deformation properties. The plastic formability of the sheet metal was significantly improved and a microstructural transformation of Oto B2 and α2occurred in this temperature region, revealing the deformation mechanism of its plasticity.

To investigate the effects of thickness and grain size on mechanical and deformation properties of C5210 phosphor bronze thin sheets, samples with different grain sizes were obtained through annealing heat treatment at different temperatures; and then tensile tests of samples with different thicknesses and grain sizes were conducted at room temperature. The results show that yield strength increases with decreasing thickness from 800 to 50 μm, but work hardening exponent and total elongation decrease, and a modified model was proposed to describe the relation between yield strength and thickness; yield strength decreases as the grain size increases, but work hardening exponent shows an increasing trend, total elongation increases to a peak and then decreases. Fracture morphology of tensile specimens was observed by SEM, which indicates that all tensile specimens are ductile fracture. The dimple intensity increases as the specimen thickness increases but reduces with the specimen grain size increasing.

Electrospun poly (lactic acid)/poly (lactic acid-co-lysine) (PLA/PLL) blend were prepared, and the structures including fibers, beads and microspheres and properties of electrospun material were characterized. Viscosity, conductivity and surface tension of electrospinning solution had critical effect on the structures of the electrospun blend. The optimization process conditions of PLA/PLL electrospun fibers, beads and microspheres were confirmed and the structures, thermal properties, crystal properties, and hydrophilicity were analyzed. The results showed that the average diameter of electrospun PLA/PLL fibers was less than that of PLA under the same spinning process, and the crystallinity of spun products was affected by solution concentration, pushing speed and spinning voltage. Accurate controlling of spinning product morphology can be achieved by adjusting the formulation of electrospinning solution and spinning process. The addition of PLL into PLA could improve the hydrophilicity of electrospun PLA/PLL products.

The multifunction treadmill from the rack, motor, adjustable power, running belts and instrument control panel composition, in order to ensure that the entire system stability and damping effectiveness of the system, the base frame all welded structures. Stent design is divided into two parts by plugging in the form of installation and removal, use of ABS plastic front and rear covers, analyzes and running with running board design, and wriggled plate design.

Mechanical properties, including fracture toughness and the fatigue crack propagation, have been investigated for two different microstructures in TC21 titanium alloy. The characteristic parameters of lamellar microstructure were measured through quantitative metallography. On the basis of analyzing the influence of microstructure on the fracture toughness of TC21 titanium alloy, the mathematical models between the fracture toughness and microstructure parameters were constructed. Furthermore, the relationship between fatigue crack growth rate and mean length values of α lamellar have been also investigated and a novel predicting model was established.

Uniaxial tensile deformation behavior of 2024 H18 aluminum sheet alloys was studied in the hot forming process with synchronous cooling temperature range of 300°C~475°C and in the strain rate range of 0.0005/s~0.1/s. The effects of temperature and strain rate on stress, elongation to facture were analyzed. And a constitutive model was proposed to describe the relationship of true stress-true stain by multiple linear regression analysis. It was found that the forming temperature and strain rate have great effect on the hot forming behavior of the alloys. The max stress reduced greatly with the increasing of temperature or reducing of strain rate, while the tensile elongation tended to rise first and then fall with the increasing of temperature and strain rate. The forming of 2024 H18 aluminum alloy at elevated temperature occurred with the strain hardening and dynamic softening. The constitutive model of 2024 H18 aluminum alloy agrees well with the experimental data.

Hot forming process with synchronous cooling is implied to improve the formability of lightweight materials with poor forming performance at room temperature. Its applicability for 6181 H18 aluminum alloy was investigated in this paper, inspired by ultrahigh strength steel hot stamping method. Uniaxial tensile test at elevated temperature with various strain rates were carried out to obtain the constitutive model for simulation and determine the parameters for further orthogonal test. The influence of temperature, holding time and cooling rate on formability and mechanical properties in the hot forming process with synchronous cooling was discussed. An optimized combination of process parameters was obtained which increased its tensile strength and elongation remarkably.

Aiming at the center shaft bracket sheet extension parts, its stamping calculation is simulated based on the sheet metal forming with nonlinear finite element software Dynaform. The contours varying with blank holder forces, friction coefficients and material performance parameters (sheet hardening exponent n and thick anisotropic coefficient r) are obtained by using the simulation software. The impact of the factors on the central shaft bracket parts stamping is analysised by using the contours, provide the theory to eliminate the fold and fracture in the stamping process.

Marine oil spill does cause huge economic losses and brings serious damages to the marine ecological environment. Therefore, how to claim compensation for oil spill damages has become very crucial for the environmental restoration. In recent years, many researchers have designed various kinds of assessment models for evaluating oil spill damages. This paper analyzes these assessment models, discusses the legal claim and technology claim, finally the suggestions for further research of oil spill damage assessment is proposed, and then the application of fuzzy neural network in technology assessment is also recommended.

Aiming at the problem of signal attenuation seriously, a block averaging pre-processing (BAP) differential coherent acquisition algorithm is proposed. BAP algorithm can be used to suppress interference signals and improve the stability of the receiver, but it is still faced with navigation signal transitions problem. Differential coherent algorithm can compensate for square loss caused by non-coherent accumulation. Monte Carlo simulation experiments show that the algorithm is more effective in the same carrier-to-noise ratio and same data length conditions.

The purpose of this paper is to study the feasibility of nano-material (1~100nm) level powder preparation by wet ball milling. The powder was used to prepare the ceramic and the performance of the ceramic was analyzed. The experimental results show that the average particle size of the powder is close to nano-material level (around 120nm) and the ceramic possess high compactness, high dielectric constant and low dielectric loss.

Seeds of 23 relic Metasequoia glyptostroboidestrees were randomly collected from their original, natural populations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old progenies were investigated. Results show that the average intra-family coefficient of variation (CV) in height growth of the 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV (14.02%). Correspondingly, these two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were significantly differed in their general combining abilities (GCA) and relative effect values of GCA (RGCA) of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high family heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in height growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboidesfor seed collection.

n this paper, a series of relevant theoretical analyses and experimental researches have been carried out for precision forming of a typical aerospace revolver. By use of the material stress relaxation principle, the finite element numerical simulation and the preforming sizing process technology of stress relaxation, it have been revealed that the new process can be used for precision forming of titanium alloy sheet and its forming precision can meet the manufacturing requirements of aerospace sheet-metal parts. The precision forming technology of titanium alloy can also be used to improve the digital manufacturing technologies of aerocraft sheet-metal parts, and thus has potential application prospects.

The thermo-stress sizing is a technology that enables sheet metal part using high elastic material such as titanium alloy to eliminate spring-back and distortion. The paper expounds and proves the principle of fixing shape of thermal stress sizing, that is, they are synthetic effects of materia1 softening and stress relaxation in short time．Then the theoretical rule of hot sizing for bending spring-back is established by this principle．On the basis of principle of the thermo-stress sizing, relevant replication experiment is implemented. The results show quantitatively effects of main factors, such as material property, part geometry, temperature and time for the rule of hot sizing． The theoretical values of spring-back in the process of hot sizing are in good agreement with that of experiments. They may be used to estimate technological parameters of thermal stress sizing．In addition thermo-mechanical characteristics under standard temperatures of forming or sizing and the experimental curves of thermo-stress sizing for Ti-6Al-4V and Ti-2A1-1.5M n are given．

The incorporation of a self-forming Cu diffusion barrier on pore-sealed SiCOH was investigated. SiCOH films 20% porous and 230 nm thick were capped with 36 nm SiO2. Fabricated structures (Cu-Mn/SiO2/SiCOH) were subjected to a back-side Secondary Ion Mass Spectrometry (SIMS) depth profile study to assess the extent of metal migration. SIMS depth profiles revealed that Cu and Mn diffused in significant amounts across the SiO2 layer during fabrication steps. A mass transport model was used to describe the migration of metal species. The diffusion coefficient for Cu in the SiO2 pore-sealing layer is approximately D[?]5.62 x 10[?]16 cm2/sec.

In this work, we use a computational model, the Eb(ER) model, and the molecular orbital theory to investigate the relationship between the molecular structures and the stabilities of three redox shuttle electrolyte additives for overcharge protection in Li ion cells: unstable 1,4-dimethoxybenzene (DMB), unstable 2,3,5,6-tetrafluoro-1,4-di-tertbytoxybenzene (TFDTB) and stable 2,5-di-tertbutyl-1,4-dimethoxybenzene (DTDMB). We propose a pathway for the proton elimination and polymerization reactions of the DMB cations, the dimerization-assistant proton elimination and polymerization reactions, and also discuss the connection of the Eb(ER) model with the chemical/electrochemical reactions, in which the redox shuttle cations are involved in Li ion cells.

As the certain basis of implementation of risk decision, risk assessment was used widely for reasonable allocation of scarce shipping oil spill response resources, but there is no a unified regulation for evaluation method. Three feasible methods of risk assessment, baseline assessment, detailed risk assessment, and combination of evaluation, are respectively introduced, including advantages and disadvantages. Then around the detailed risk assessment, present shipping oil spill environmental damage risk assessment study in China and abroad are then introduced in detail. Environmental damage assessment and oil spill risk assessment are introduced respectively including instantly popular appraisal methods, research hot spots and the most comprehensive evaluation model. Finally the possible direction of development of risk assessment is put forward in order to provide certain inspiration and references in developing domestic risk assessment.

A scientific analysis on the geographical environments and regional geological tectonic features of some notable earthquakes over the world revealed the root cause of tectonic earthquakes—that is, a tectonic earthquake is generally caused by underground water erosion instead of inter-continental plate collision. According to this new law, it’s easy to explain many past great earthquakes around the world, and also easy to predict some future possible earthquake foci by observing landforms, that is, great earthquakes occur easily in coastal areas, or areas retaining large amounts of water, but not in areas lacking water. So these research results are important to economically protecting against earthquakes and reducing disasters. Especially, according to this new explanation, many digital seismograph networks in the world can be improved. Through on-the-spot investigation or observing topographic maps, one can find that Xi’an urban area and some of its surrounding areas lack underground water, and the possibility of devastating earthquakes occurring in these areas is vey low. Hence the observation on these areas can be lessened. But some areas such as Weihe down-faulted basin near Huaxian and Huayin is seismic risk area, the observation on these areas should be enhanced.

It is a dip slope with mudstone and sandstone interbedded at the northward 363K National Highway NO.3. in Taiwan. The Figure 1 showed the slope sliding due to continuous heavy rain on August 19, 2010. This study analyses the slope stability by the finite element method of program PLAXIS-2D, and explores the suitability of various control engineering methods. It is named analysis before design with anchors in this study before September 2010. The aim is to search the original parameters of the ground by comparing a potential sliding surface with monitor data of site. Then countermeasure analyzes the impact based on the loss of anchor prestress and the row of piles set. From the results of analysis, sliding surface analysis and the data which was derived from the early monitor judgments are consistent. The ground anchor has been unable to achieve good stable slope effect for the slope sliding, due to heavy rains. However, the rows of pile construction significantly improved the stability of the slope.

The phylogenetic diversity of phosphate solubilizing bacteria (PSB) distributed in P-rich soils in the Dianchi Lake drainage area of China was characterized, and the tricalcium phosphate (TCP) solubilizing activities of isolated PSB were determined. Among 1 328 bacteria isolated from 100 P-rich soil samples, 377 isolates (28.39% of the total) that exhibited TCP solubilization activity were taken as PSB. These PSB showed different abilities to solubilize TCP, with the concentrations of solubilized P in bacterial cultures varying from 33.48 to 69.63 mg L−1. A total of 123 PSB isolates, with relatively high TCP solubilization activity (> 54.00 mg L−1), were submitted for restriction fragment length polymorphism (RFLP) analysis, which revealed 32 unique RFLP patterns. Based on these patterns, 62 representative isolates, one to three from each RFLP pattern, were selected for 16S rRNA sequencing. Phylogenetic analysis placed the 123 PSB into three bacterial phyla, namely Proteobacteria, Actinobacteriaand Firmicutes.Members of Proteobacteriawere the dominant PSB, where 107 isolates represented by 26 RFLP patterns were associated with the genera of Burkholderia, Pseudomonas, Acinetobacter, Enterobacter, Pantoea, Serratia, Klebsiella, Leclercia, Raoultellaand Cedecea. Firmicuteswere the subdominant group, in which 13 isolates were affiliated with the genera of Bacillusand Brevibacterium.The remaining 3 isolates were identified as three species of the genus Arthrobacter.This research extends the knowledge on PSB in P-rich soils and broadens the spectrum of PSB for the development of environmentally friendly biophosphate fertilizers.

Straight TC4 wire rod is demanded by many industries, however the technology of straightening for it has not been solved. In the present paper, a horizontal-vertical roller thermal straightening system is designed and the theory of rolling reduction is concluded. Based on the new system and the rolling reductions calculated for each roller, the method of finite element analysis is used to show the process of straightening at 600℃. The result of straightening is ideal, which proves the straightening system is adequate for Φ4.5 TC4 wire rod.

In this paper, the operating conditions of air-conditioning systems in Terminal building of Guilin LiangJiang International Airport were tested and analysed. This paper mainly analyzes the influence of chilled water temperature on water chiller performance and derives the relationship of COP of water chiller and chilled water temperature difference between inlet and outlet , and provides reference for operation mode’s optimization of the air-conditioning system and energy consumption reduction of the whole building.

In the oil drilling engineering, the choice of the best bit-type can improve penetration rate, shorten the drilling cycle time and speed up the oil field exploration and development pace. The drill bits type optimal selection has important meaning in oil drilling engineering. Based on the brief introduction of fractal theory, it pointes out that the fractal theory can describe the depositional sequence of formations with self-similar characteristics in this paper. It puts forward a method of calculating correlation dimension with multivariate model according to log information. It has also established statistical relationship between correlation dimension and the working performance standard of bits. At the end of the paper the bit types selection method, adopting the correlation dimension, has given out. This method is practically feasible through the example validation.

Grinding strengthening and hardening can change and improve the ground surface integrity directly by the composite process of thermal load and mechanical force during process. The thickness and distribution of strengthening layer in ground surface makes the key role to measure the surface integrity of workpiece. The hardness and size of strengthening layer can influence the fatigue strength working life of the workpiece significantly. Based on the grinding strengthening test of 45 steel specimens, the strengthened layer microstructure, thickness and surface hardness were analyzed. This study illustrates the mechanism of grinding strengthened layer formation and also provides the theoretical basis for grinding strengthening and hardening layer quality control and grinding strengthening process making properly under small depth of cut conditions.

The main defect of shrink flanging wing rib is wrinkling in rubber bladder hydroforming. In the aeronautical field, the side blank holder is usually used to avoid wrinkling. In order to obtain appropriate parameters of side blank holder, it be carried out that the simulation analysis for the process of the high hydraulic press rubber forming processes of high shrink flanging with side blank holder by the ABAQUS finite element software. Besides, the corresponding experiments verified also be implemented. The research results show that the sheet metal tends to wrinkle along with decrease of the blank lap width and increase of these parameters such as the distance between side blank holder and die, the dip angle and fillet radius of the side blank holder.

The process of injection mould design and manufacture was introduced by taking the cover as an example. Firstly, the 3D model of the part and the injection mould structure were designed based on SolidWorks software. Secondly, the injection molding progress was analyzed and simulated based on Moldflow software. Finally, the toolpaths of cavity and core were designed based on MasterCAM software, and its manufacture process and numerical control programming was simulated. The period of product development was shortened effectively and the quality of design and manufacture was improved by CAD/CAE/CAM integrated technology.

Apply the function of FBM Mill and FBM Drill built in MasterCam to achieve the automatic NC programming and machining of solid parts.The feature modeling of parts is produced in Solidworks, and then converted to MasterCam. After the stock size of parts and FBM parameters are set, the features of parts are recognized automatically; and all of the 2D toolpaths of parts are automatically generated in a specified machine. Finally, the automatically generated NC toolpaths based on features are verified by simulating. FBM technology is adopted to eliminate the manual processes involved in identifying features for programming milling and drilling operations on solid parts, thus greatly increasing the efficiency and flexibility of programming, which is an effective method of achieving automatic NC programming.

Calcium carbonate (CaCO3) whiskers were firstly treated by sodium stearate, and then blended with polypropylene (PP) to prepare the composites by a closely intermeshing co-rotating twin-screw extruder at 200℃. The performance of the composites, such as thermal behavior, microstructure and mechanical properties, were analyzed with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and mechanical testing. The results showed that CaCO3 whisker influenced the crystalline behavior of PP phase in the blends because of its intervening. Moreover, thermo-decomposing temperature, tensile and bending strengths of the blends all increased with increasing whisker content. CaCO3 whiskers had good reinforcing and toughening effects on PP.

Lead‐free (1−x)Ba(Zr0.15Ti0.85)O3–x(K0.5Na0.5)NbO3; x=0–0.05) (BZT–KNN) perovskite ceramics, a materials with potential applications for energy storage, are investigated. The samples are prepared by a solid‐state reaction method. Powder X‐ray diffraction (XRD) and scanning electron microscopy (SEM) are used to study the microstructure of the samples. Their dielectric properties and impedance spectra are reported as functions of temperature and frequency. The addition of 1 mol % (K0.5Na0.5)NbO3to Ba(Zr0.15Ti0.85)O3improves the dielectric constant and enhances its diffuseness in a wide temperature range. The small amount of (K0.5Na0.5)NbO3is found to markedly affect the microstructure of the Ba(Zr0.15Ti0.85)O3ceramic (grain size and other characteristics) without changing the phase or crystal symmetry. In addition, we report that fine substructures in the grains, so‐called sheet structures, are responsible for the dielectric properties (both diffuseness and dielectric constant) of (1−x)Ba(Zr0.15Ti0.85)O3–x(K0.5Na0.5)NbO3(x=0–0.03; especially x=0.01) ceramics.