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Herein, we developed a highly selective, efficient, and simple method for direct transamidation of thioamides with amines, promoted by commercially available acetophenone under metal-/solvent-free conditions. The reaction tolerated a wide range of functional groups and substrates, including single- or double-thioamides, benzylamines, or alkyl/cycloalkyl-substituted aliphatic amines. The present protocol can be applied to gram-scale in good yields. In addition, the Pt-/Ni-complexes of double-transamidation products were obtained in good to excellent yields. The investigation of photophysical properties indicated that the fluorescence spectra of Pt-complexes showed an emission band centered at 550–750 nm and exhibited red fluorescence when irradiated by a UV lamp (365 nm).

The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1–4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet’s transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense–Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.

The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of 8.4−1.1+0.5Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.

Multi-laser powder bed fusion (ML_PBF) can improve the efficiency of traditional single-laser process, but the study on the potential defects causing by the introduction of multiple lasers is still open. In this paper, the particle-scale computational fluid dynamics (CFD) method is used to simulate the molten pool behavior of nickel-based superalloy in triple-laser PBF (TL_PBF) process with low energy density. The processing parameters on the flow and temperature fields and balling phenomenon in the TL_PBF process are mainly studied. The comparison between the simulation and the experimental results shows that the proposed model is reliable and can reproduce the balling phenomenon. The simulation results show that in the competition of three melt flows, the molten track of the main laser is randomly deviated to one of the molten tracks of the auxiliary lasers due to the uneven distribution of the powder bed. In the TL_PBF process, the larger the vertical offset is, the more serious the balling phenomenon is. When the parallel offset is larger than the sum of the radii of the two adjacent lasers, the larger the parallel offset is, the more the pits generated on the surface of the molten tracks are, leading to the extreme degradation of surface quality. It can be concluded that the synchronous TL_PBF with low energy density can obtain better surface quality when the parallel offset is about the sum of the radii of two adjacent lasers. This work can be used to guide multi-laser additive manufacturing to improve products with better surface quality.

We aim to reveal the structure and kinematics of the Outer Scutum–Centaurus (OSC) arm located on the far side of the Milky Way through very long baseline interferometry (VLBI) astrometry using KaVA, which is composed of KVN (the Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We report the proper motion of a 22 GHz H2O maser source, which is associated with the star-forming region G034.84−00.95, to be (μαcos δ, μδ) = (−1.61 ± 0.18, −4.29 ± 0.16) mas yr−1in equatorial coordinates (J2000.0). We estimate the 2D kinematic distance to the source to be 18.6 ± 1.0 kpc, which is derived from the variance weighted average of kinematic distances with local standard of rest velocity and the galactic-longitude component of the measured proper motion. Our result places the source in the OSC arm and implies that G034.84−00.95 is moving away from the Galactic plane with a vertical velocity of −38 ± 16 km s−1. Since the H isupershell GS033+06−49 is located at a kinematic distance roughly equal to that of G034.84−00.95, it is expected that gas circulation occurs between the outer Galactic disk around G034.84−00.95 with a Galactocentric distance of $12.8^{+1.0}_{-0.9}\:$kpc and the halo. We evaluate possible origins of the fast vertical motion of G034.84−00.95, which are (1) supernova explosions and (2) cloud collisions with the Galactic disk. However, neither of these possibilities are matched with the results of VLBI astrometry or the spatial distributions of H iiregions and H igas.

Dibutyltin benzoin benzoyl hydrazone complex I[C6H5(O)C=N-N=C(Ph)CH(Ph)O]2[(n-Bu)2Sn]2and dibutyltin benzoin salicyl hydrazone complex II[2-(OH)-C6H4(O)C=N-N=C(Ph)CH(Ph)O]2[(n-Bu)2Sn]2were synthesized and characterized by IR, 1H, 13C and 119Sn NMR spectra, HRMS, elemental analysis and thermal stability analysis, and the crystal structures were determined by X-ray diffraction. The crystal of complex Ibelongs to monoclinic system, space group P21/nwith a =11.1942(8), b= 10.4754(7), c =23.6700(17) Å, ß =101.529(2)°, Z= 2, V =2719.6(3) Å3, Dc= 1.371 Mg·m−3, µ(MoKα) = 0.966 mm−1, F(000) = 1152, R= 0.0458 and wR= 0.1312. The crystal of complex IIis of triclinic system, space group P1−with a =9.9960(4), b =11.2466(4), c =14.0509(5) Å, α = 69.4190(10)°, ß=70.0600(10)°, γ = 81.8090(10)°, Z= 1, V =1389.69(9) Å3, Dc=1.380 Mg·m−3, µ(MoKα) =0.950 mm−1, F(000) = 592, R =0.0284 and wR =0.0690. In vitroantitumor activities of both complexes were evaluated by CCK8 method against three human cancer cell lines (MCF7, NCI-H460 and HepG2), and complex IIexhibited better antitumor activity than I. The interaction between complexes and calf thymus DNA was studied by UV-vis, fluorescence spectroscopy and viscosity measurements.

Schiff base pyridine zinc(II) complexes 1~4were synthesized by the reaction of the 2-((2-hydroxybenzylidene)amino)phenol Schiff base with appended donor functionality, zinc acetate, and pyridine. The results of the structural characterization of the complex show that they have the same coordination mode and similar steric structure. Complexes 1and 3form a one-dimensional chain structure and two-dimensional grid structure by lots of hydrogen bonds, respectively. Thermogravimetric analysis shows complexes 1~4can exist stably below 150 °C. The results of the fluorescence quenching experiments between the complexes and DNA-EB show that the interaction between them is intercalation, and the effect of complex 1is the most obvious. It is speculated that the steric hindrance of complex 1is relatively small, and the aromatic ring on the ligand is more likely to inserted into the base pair of DNA.

PurposeUniversal germline testing in patients with colorectal cancer (CRC) with a multigene panel can detect various hereditary cancer syndromes. This study was performed to understand how to choose a testing panel and whether the result would affect clinical management.MethodsWe prospectively enrolled 486 eligible patients with CRC, including all patients with CRC diagnosed under age 70 years and patients with CRC diagnosed over 70 years with hereditary risk features between November 2017 and January 2018. All participants received germline testing for various hereditary cancer syndromes.ResultsThe prevalence of germline pathogenic variants (PVs) in cancer susceptibility genes was 7.8% (38/486), including 25 PVs in genes with high-risk CRC susceptibility (the minimal testing set) and 13 PVs in genes with moderate-risk CRC susceptibility or increased cancer risk other than CRC (the additional testing set). All the clinically relevant PVs were found in patients diagnosed under age 70 years. Among them, 11 patients would not have been diagnosed if testing reserved to present guidelines. Most (36/38) of the patients with PVs benefited from enhanced surveillance and tailored treatment. PVs in genes from the minimal testing set were found in all age groups, while patients carried PVs in genes from the additional testing set were older than 40 years.ConclusionUniversal germline testing for cancer susceptibility genes should be recommended among all patients with CRC diagnosed under age 70 years. A broad panel including genes from the additional testing set might be considered for patients with CRC older than 40 years to clarify inheritance risks.Trial registration numberNCT03365986.

A three-dimensional high-fidelity particle-scale computational fluid dynamics (CFD) modeling of a selective parallel dual-laser melting (SPDLM) process is developed, on which dynamics behavior of molten pools of Nickel-based superalloy during SPDLM is simulated. The phenomena of wetting, necking, and pores near the overlapping region in the parallel dual-laser molten pools are especially investigated. The simulated results show that the SPDLM process improves the re-melting rate of the molten pool and the wettability of the overlapping region of the SPDLM molten pool, reducing the probability of defects, especially the probability of lack of fusion. Due to the uniform temperature distribution in the overlapping region of the two tracks and the complete melting, the product quality at the overlapping region of the two molten pools can be better guaranteed when the interval between the parallel dual lasers is 2.5 times of the laser beam radius. The results suggest that the SPDLM technique together with appropriate process parameters can not only increase the printing efficiency, but also improve the surface quality of the overlapping area of the two molten pools. The simulated results also reveal the formation mechanisms of pore defects during the selective multi-laser melting process on a mesoscopic scale. This study shows that the proposed particle-scale CFD model provides a high fidelity approach to characterize the molten pool in the SPDLM process and, therefore, is helpful for the optimal process design for the selective multi-laser melting.

•H2S restores the impaired hippocampal neurogenesis in STZ-induced diabetic rats.•H2S upregulates the PI3K/AKT pathway in the hippocampus of STZ-induced diabetic rats.•LY294002 reverses the improvement of H2S on the hippocampal neurogenesis in STZ-induced diabetic rats.•LY294002 abolishes the antidepressant-like role of H2S in STZ-induced diabetic rats.

The polyandrous mating behavior of the honeybee queen increases the genetic variability among her worker offspring and the workers of particular subfamilies tend to have a genetic predisposition for tasks preference. In this study, we intended to understand whether there is nepotism in dance communication of honeybees during natural conditions. Microsatellite DNA analyses revealed a total of fourteen and twelve subfamilies in two colonies. The subfamily composition of the dancer and the followers did not deviate from random. The majority of the subfamilies did not show kin recognition in dance-recruit communication in honeybee colonies, but some subfamilies showed significant nepotism for workers to follow their super-sister dancer. Because it seems unlikely that honeybee would change the tendency to follow dancers due to the degree of relatedness, we conclude that honeybees randomly follow a dancer in order to e benefit colony gain and development.

BRAFand MLH1promoter methylation testings have been proven effective prescreens for Lynch Syndrome. We aimed to compare different screening strategies for Lynch Syndrome in patients with MLH1(−) CRC. Patients with MLH1(−) CRC who had been tested for BRAFmutation and germline variants of DNA mismatch repair genes were included. We compared the sensitivities and specificities for identifying Lynch Syndrome and the cost-effectiveness of four screening approaches that used the following tests as prescreens: BRAFtesting, MLH1methylation testing, MLH1methylation & BRAFtesting, and MLH1methylation testing & Revised Bethesda Criteria. Of 109 patients included, 23 (21.1%) were Lynch Syndrome patients. BRAFmutation and MLH1methylation occurred in 6 (5.5%) and 40 (36.7%) patients, respectively. The sensitivity for identifying Lynch syndrome of BRAFtesting was 100%, but the specificity was only 7%. MLH1methylation testing had a lower sensitivity than BRAFtesting (97.5% vs 100%), but had a markedly higher specificity (45.3% vs 7%). The combination of the two testings had a slightly higher specificity than MLH1methylation testing alone (47.7% vs 45.3%). The MLH1methylation testing approach had a 10% lower cost of identifying MLH1(−) Lynch syndrome carriers per case than universal genetic testing, but it missed 4.5% of patients. BRAFand MLH1promoter methylation testings as prescreens for Lynch syndrome are less effective in Chinese patients with MLH1(−) CRC than in their Western counterparts. Universal genetic testing could be considered an up-front option for this population.

Background: Medical test orders can display the physiological functions of patients by using medical means. The medical staff determines the patient's condition through medical test orders and completes the treatment. However, for most patients and their families, there are so many terminologies in the medical test list and they are inconvenient to understand and query, which would affect the patients’ cognition and treatment effect. Therefore, it is especially necessary to develop a consulting system that can provide related analysis after getting medical test data. Objective: This paper starts with information acquisition and speech recognition. It proposes a natural scene information acquisition and analysis model based on deep learning, focusing on improving the recognition rate of routine test list and achieving targeted smart search to allow users to get more accurate personalized health advice. Methods: Based on medical characteristics, considering the needs of patients, this paper constructs an APP-based conventional medical test consultation system, using artificial intelligence and voice recognition technology to collect user input; analyzing user needs with the help of conventional medical information knowledge database. Results: This model combines speech recognition and data mining methods to obtain routine test list data and is suitable for accurate analysis of problems in routine check-up procedure. The app provides effective explanations and guidance for the treatment and rehabilitation of patients. Conclusion: It organically links the Internet with personalized medicine, which can effectively improve the popularity of medical knowledge and provide a reference for the application of medical services on the Internet. Meanwhile, this app can contribute to the improvement of medical standards and provide new models for modern medical management.

A nonlinear spring model is proposed to investigate the oscillation behavior of oscillators based on double-walled carbon nanotubes (DWCNTs) with open end by using the finite element (FE) method, where non-linear spring elements are used to represent the van der Waals (vdW) interaction between tubes. Compared to the linear spring FE model, the proposed non-linear springs can more accurately describe the interaction between nanotubes because the vdW interaction is a kind of strongly non-linear force. The influence of boundary conditions, geometric parameters of the DWCNTs, and the layer spacing of tubes on the natural frequencies is especially studied. Various oscillation modes and the corresponding natural frequencies are obtained. Compared to the results obtained by using the linear spring model, the natural frequencies of oscillators based on DWCNTs are in qualitatively better agreement with those obtained from the analytical method and the molecular dynamics (MD) method. From the FE results, it also can be seen that, DWCNTs is expected to be a nanoscale oscillatory device, and its oscillation mode and natural frequency can be adjusted by changing the geometric parameters and boundary condition of the tubes. The proposed nonlinear spring model is helpful for the design of the nano-oscillators under various conditions.

The phenomenon of periodic cross striation of GOA products is discovered as well as the mechanism and influencing factors are studied. Common electrode voltage (Vcom) distortion caused by the same period of CLKs affects the pixel holding voltage. CLK signal as a low frequency AC signal is transmitted to Feed through capacitances (common electrode is CF BM), and then Feed signal has distortion with period as CLK. The Vcom distortion comes from the reverse and amplified Feed distortion by compensators. By reducing the capacitance square (reducing CF BM area and/or Feed line length), the influence of CLK signal on Feed is decreased. By reducing the capacitance permittivity through changing the position and width of Sealant, the signal coupling between CLK and Feed is effectively diminished.

Aortopulmonary window (APW) is a rare congenital heart anomaly. A total of 8 cases with APW confirmed by echocardiography and surgery were retrospectively reviewed and the echocardiographic features analyzed. Among the 8 APW cases, 5 were type II and 3 were type III, the latter of which includes 2 cases complicated with Berry syndrome. Prenatal echocardiography can provide accurate information for the diagnosis of fetal APW. The prognosis depends on the timing of surgery and the nature of the associated cardiac anomalies.

寻找一个Lynch 综合征患者所在家系携带的DNA 错配修复基因突变,探讨各突变对肿瘤发生发展 的影响 MLH1的第19 号外显子c.2250_2251insAA 移码 突变既往被认为是意义未名突变,而我们的研究 为明确该突变的致病意义提供了依据。另外,我 们首次报道了MLH3 基因第1 号外显子 c.1397C>A 突变。该突变有可能使Lynch 综合征 患者的发病年龄提前。 运用免疫组织化学技术检测家系先证者肿瘤组织 中错配修复基因蛋白的缺失情况,使用二代测序 技术通过先证者血标本明确患者所携带的突变。 同时运用Sanger 法检测家系其他成员该突变的 携带情况以明确突变对肿瘤发生发展的影响。 我们在患者体内发现MLH1 基因第19 号外显子 移码突变(c.2250_2251insAA)以及 MLH3 基因 第1 号外显子c.1397C>A 突变。在患者家系中, 我们仅检测到有MLH1 突变,因此该突变极有可 能为致病突变。

This study demonstrated that a Ru-Ni bimetallic core-shell catalyst (0.6%Ru-Ni)@SiO2with a proper surface Ru concentration is superior in achieving better catalytic activity and tunable H2/CO ratio at a comparatively lower reaction temperature (700 °C). Compared to the impregnation method, the hydrothermal approach leads to a highly uniform Ru distribution throughout the core particles. Uniform Ru distribution would result in a proper surface Ru concentration as well as more direct Ru-Ni interaction, accounting for better catalyst performance. Enriched surface Ru species hinders surface carbon deposition, but also declines overall activity and H2/CO ratio, meanwhile likely enhances Ni oxidation to certain degree under the applied reaction conditions. Over the current (m%Ru-Ni)@SiO2catalyst, the formation of fibrous carbon species is suppressed, which accounts for good stability of catalyst within a TOS of 10 h.

In this study, three α-Fe2O3crystallites of regular morphology (truncated hexagonal bipyramid, quasi cubic, and hexagonal plate) were prepared in a controllable manner. Based on the (HR)TEM and SEM characterizations, the exposed crystal facets of three α-Fe2O3crystallites, namely {113}, {214}, {104}, {110}, {012}, and {001}, were carefully identified. Au nanoparticles of ca.2.0 nm with a narrow particle size distribution were essentially monodispersed on the three α-Fe2O3substrates through a controlled deposition strategy. In such a way, the Au/α-Fe2O3interfacial structures with structurally defined oxide substrates and nearly identical Au particle size and morphology have been obtained. The systems allowed us to compare in depth the behaviors of distinct surfaces/interfaces in CO oxidation. The characterization including O2/surface hydroxyl-TPD, CO-TPSR, and in situFTIR clarified the role of the surface oxygen/hydroxyl species in developing crucial intermediates on distinct interfaces. The results demonstrated that the evolution of different intermediates (CO32−and HCO2−) was directly controlled by interfacial features, i.e., the weakly adsorbed oxygen and surface hydroxyl species as well as the specific Au–Fe2O3boundary structure, which meaningfully determined CO activation and conversion to CO2. The present study provided new insights into the significance of Au/α-Fe2O3interfacial structures governing the evolution of reaction intermediates in CO oxidation.

The oscillatory behaviors of an oscillator made from double-walled carbon nanotubes (DWCNTs) with vacancy defects were systematically investigated via molecular dynamics simulation method. We found that the vacancy defects change the off-axial rocking motion and the van der Waals potential, resulting in more energy dissipation. Unlike the case in the C60–nanotube oscillators (Song, et al., Phys. Lett. A. 373 2009, 1058-1061) that one vacancy can make the oscillators more stable, our study showed that the vacancies cannot improve the performance of DWCNT-based oscillators no matter where vacancy defects are located.

Objective The treatment and incidence of femoral neck fracture (FNF) in older patients is controversial. We investigated the new AO (Arbeitsgemeinschaft für Osteosynthese) classification in patients with FNF by age to determine the proportions of stable fracture and change trends according to patients’ age.Methods We divided patients with FNF hospitalized in Xi'an Honghui Hospital from 2018 to 2020 into five groups according to age: young (<50 years), middle-aged (50–59 years), young-elderly (60–69 years), middle-elderly (70–79 years), and very elderly (≥80 years) groups. We retrospectively collected data of patients’ sex, admission date, fracture side, mechanism of injury, and new AO classification.Results In total, 2071 patients were included for analysis, with 1329 women (64.2%); 1106 patients (53.4%) had left-side fracture. The main mechanism of injury was falling. In the young-elderly, middle-elderly, and very-elderly groups, 33.3%, 29.2%, and 24.1% had stable fracture type, respectively). The proportion of patients with FNF did not show a change trend by age during the 3-year investigation period.Conclusion In our study, the proportion of older patients with FNF did not increase, and as many as a third of patients with FNF aged 50 to 70 years had stable fracture.

Burnt lime is an important material in steelmaking and its activity degree is a key factor for liquid steel quality. The burnt lime was made by the calcination of limestone in a high pressure electric furnace. The burnt lime mineralogical phases and micro-morphologies were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The burnt lime activity degree was determined by acid-base titration, the burnt lime pore distribution was measured by mercury intrusion porosimetry (MIP), and the thermal effect of a mixture of burnt lime and slag was measured by differential scanning calorimetry (DSC). The results showed that the CaO grain size and pore size of burnt lime made under high pressure were larger than those of burnt lime made under atmospheric pressure. The CaO grain size and pore size increased and the laminate phenomenon also occurred clearly under high pressure. The activity degree of burnt lime made under high pressure was greater than that made under atmospheric pressure. The maximum activity degree was 437 mL for burnt lime made under a pressure of 0. 4 MPa. For the same ratio of CaO to SiO2, the melting temperature, hemisphere temperature and fluidity temperature of slag decreased with increasing burnt lime activity degree. The higher the activity degree the burnt lime had, the better the slag forming occurred. It was advantageous for 2CaO · SiO2and 3CaO · SiO2forming at lower temperatures if the burnt lime activity degree was increased.

In this study, an atomistic simulation was performed to investigate intrinsic resonance propensity of clamped-clamped copper nanowires with Σ5 (310)/[001] symmetric tilt grain boundary. Grain boundary energy γGB for bicrystal structure was calculated based on an iterative approach. The stable atomic configuration was then doubly clamped and excited via flexural oscillation under varied temperatures. From the result, the appearance of grain boundary significantly alters the resonance properties of Cu nanowires. Greater attenuation in kinetic energy can be observed with increased temperature. Quality factors attains Q ~ 1/T0.7144 and 1/T0.7249 with temperatures from kinetic energy and centroid root mean square spectrum, respectively, where the former seems more reliable to employ at elevated temperatures.

Yams (Dioscoreaspp.) are widely cultivated as edible resources and medical materials in China. Characterizing chemical compositions in yam germplasm is crucial to determine their diversity and suitability for food and medicine applications. In this study, a core germplasm containing 25 yam landraces was used to create an effective classification of usage by characterizing their nutritive and medicinal compositions. All studied landraces exhibited high contents of starch from 60.7% to 80.6% dry weight (DW), protein (6.3–12.2% DW), minerals (especially Mg 326.8–544.7 mg/kg DW), and essential amino acids. Allantoin and dioscin varied considerably, with values of 0.62–1.49% DW and 0.032–0.092% DW, respectively. The quality variability of 25 yam landraces was clearly separated in light of UPGMA clustering and principal component analysis (PCA). Using an eigenvalue ≥1 as the cutoff, the first three principal components accounted for most of the total variability (62.33%). Classification was achieved based on the results of the measured parameters and principal component analysis scores. The results are of great help in determining appropriate application strategies for yam germplasm in China.

This study aimed to evaluate the safety and efficacy of a new nickel-titanium shape memory alloy compression anastomosis ring, NiTi CAR 27, in constructing an anastomosis for colorectal cancer resection compared with conventional staples.

The stability of additively manufactured products is mainly affected by their pore defects and surface quality and critical in their applications in various engineering fields. Based on this understanding, a three-dimensional high-fidelity particle-scale computational fluid dynamics (CFD) model for a sequential dual-laser powder bed fusion (SDL_PBF) process was developed in this paper. Using the model, the mechanism of improving the product quality of nickel-based superalloy GH4169 by dual laser sequential scanning strategies was particularly discussed. The effects of laser powers and offsets of sequential dual lasers on the molten pool wetting, pores, and necking were also specially studied, in which the process parameter window was determined through orthogonal experiments. The CFD simulations showed that, when the offsets of the sequential dual lasers are about 3.7 times of the laser radius, the wetting of the molten pool is the best in our test, because the molten pool flows around, resulting in a larger overlapping area. The SDL_PBF with a suitable rear laser source can eliminate the pores and the entrained air formed by the collapse of the recoil depression, which in turn is caused by the front laser. This is because the recoil depression generated by the rear laser can break down the pores caused by the incomplete melting of the front laser, so that the gas in the pores communicates with the air outside, and the liquid in the molten pool is replenished, thereby eliminating the pores and reducing the porosity of the product, which is consistent with the experimental results. In addition, the simulation results showed that the molten pool can flow stably and quickly due to the combined action of strong Marangoni force and steam recoil force as well as weak surface tension in the case of the SDL_PBF with appropriate process parameters, resulting in greatly improved surface quality. Therefore, this work can provide a way for improving multi-laser additive manufacturing of high-performance products.

The system uses the MVC framework model for system integration, processing data through the view, the controller reads the data from the view, and send the model to control user input data, the model object is responsible for accessing data in the database. Using the controller decoupling performance logic and business logic, in order to improve system maintainability, scalability and reusability, effective separation of business logic, data, and interface display implementations.

According to different node data access objects, and based on the idea of behavior-driven development, an interface-oriented node data access tool is designed and implemented. The tool mainly implements an executable node data access tool that is based on MFC, and writes a set of Win32 console application, which improves the node data automation access scripts and encapsulates the module interfaces, thus improving the distributed network data access speed.

For improving the quality of vocational education evaluation validity, this paper introduces the research progress of teaching evaluation, use data mining technology to put forward a feasible model of higher vocational teaching quality evaluation, construct a decision tree has practical significance. By the method used, the traditional Apriori algorithm is improved decision tree to improve the teaching contents to the location of the second master node, reflecting the characteristics of vocational teaching practice. Case analysis indicated, the decision tree has a good operability and high credibility.

This article is from the financial perspective to analyze the investment value of listed companies. Using independent two-sample T-test method and factor analysis of selected financial ratios, by building a logistic regression model for agricultural investment value of listed companies to judge, provides a method for determining the value of investments to investors.

Based on the theory of fracture mechanics and finite element method, this paper presents a numerical calculation of typical experimental models, with emphasis on calculation of the stress intensity factor of I-type crack. A two-dimensional finite element analysis of a plate sample including an initial crack was carried out to study the propagation of a fatigue crack under multiaxial loadings. The effects of crack length and the multiaxial condition on the stress intensity factor were especially investigated. Our present approach provides an effective method for edge crack fracture criterion under complex loading calculation.

According to the status of vocational teaching quality evaluation, this paper will have an analysis of the AHP that is used to quantify the qualitative classroom teaching quality evaluation. It is applied to determine the weights of evaluation factors, to build a hierarchical model of teaching quality evaluation, to analyze implementation steps of AHP: construct hierarchical model-determine the weight of each factor-derived decision alternatives. Questionnaire analysis has proved that this method not only can be used to have a comprehensive evaluation of teaching quality but also to have an evaluation on the secondary index. The method is scientific, rational and has a high application value.

Aiming to improve the efficiency of access to remote database in the virtual laboratory design, the paper analyzes features and shortness of the LabView to have access to remote database and elaborates methods and programming model for LabSQL to implement database access and proposes the integrated application strategy of the LabSQL toolkit and ADO technology. Combined with a network virtual laboratory’s application development, the paper provides access steps based on LabSQL database and virtual laboratory’s design process and it is proved that the program is easy to implement and easy to use.

In order to improve the efficiency of intelligence algorithm in integration planning and to avoid “premature” phenomenon, an improved genetic algorithm strategy-a method based on fitness density and scaling is proposed in the paper. It applies a new encoding way of integration planning. The two examples of simulation experiments show that the genetic improvement strategy could significantly reduce solving algebra and prevent “premature” phenomenon.

With the increase of Ti-bearing blast furnace slag, its harm is growing. It contains high titanium content. How to make good use of Ti-bearing blast furnace slag is currently a hot problem. In this paper, the conditions of comprehensive utilization on Ti-bearing blast furnace slag were described firstly. Then the features, application field and problems of extraction and non-extraction titanium from Ti-bearing blast furnace slag were introduced. The advantages, disadvantages and problems of comprehensive utilization of Ti-bearing blast furnace slag were analyzed. Finally the application prospects were forecasted.

At present steel industry is obtained a rapid development in China. More and more steel slag is accumulated. How to deal with steel slag becomes a hot problem. In this paper, the source, composition and characteristics of steel slag are introduced firstly. Then the methods of comprehensive utilization on the steel slag are summarized. Finally the problems are put up and the development trend of steel slag utilization is prospected according to the present situation of comprehensive utilization of steel slag.

Carbon nanotubes have unique physical and chemical, electrical, mechanical properties. As a new nanomaterial, it has great development potential. In this paper, the structure and properties of carbon nanotubes were briefly described, and the commonly used ways of preparation of carbon nanotubes were also introduced in detail. The importance of the development of new synthetic methods was put forward.

At present, Java technology is the most popular technology in IT industry. Concerning the IT talents, Java technology belongs to the serial professional technology with the most industrial employment competitiveness, and the working process systemization is the most effective training mode to cultivate IT talents. In this paper, a set of Java technology modules were designed and optimized with the theoretical guidance of the working process systemization, and the modules mainly included Java, JavaScript, XML, Java Web and JavaEE. The series of modules follows the action-oriented cognitive rules with a good operability. Moreover, it can effectively enhance the industrial employment competitiveness of the IT talents, and have a great practical application value to cultivate and improve the skills for IT talents.

The database design is one of three key points for the construction of management information system, which is directly related to the pros and cons of the application systems functional structure, system performance and data safety. In this paper, according to the business operation feature of commercial bank credit management system and combined with the relational database modeling, database design technology and database management operation mechanism, the design key links of commercial bank credit management system was detailed analyzed from the application perspective, and the corresponding solutions were provided.

The self-organizing thought of the network resource based on Web2.0 can innovatively combine the web page and instant communication, realize the function for the normal user to add, find and enter into the chat room for any web page at the client side, and the users browsing the same URL and website can enter into the same chat room to communication, thus providing the communication place for all users visiting the same web page and achieving the aim to improve the visitor activity, user viscosity and visitor conversion rate of the site.

Segmentation of brain tissues from magnetic resonance (MR) images plays a crucial role in medical image processing. In this paper, we propose an automatic unsupervised segmentation method integrating wavelet transform with self-organizing map for brain MR image. Firstly, a multi-dimensional feature vector is constructed based on the intensity, the low-frequency subband of wavelet transform and spatial position information. Then, an adaptive growing self-organizing tree map (AGSOTM) is presented, which adaptively captures the complicated spatial layout of the individual tissues, and overcomes the problem of overlapping grey-scale intensities for different tissues. The proposed method is validated by extensive experiments using both simulated and real T1-weighted MR images, and compared with other algorithms.

Based on the Budiansky-Roth motion criterion, a thin cylinder shell finite element model is established using the finite element software (ABAQUS) to systemically investigate the dynamic bucking behavior of single-walled carbon nanotubes, which is validated by the molecular dynamic model. It is shown that both the magnitude and duration of the impact load have a great influence on the critical buckling load. By comparing the buckling modes, it can be found that the stress wave propagation plays an important role on the buckling deformation. A local axisymmetrical buckling mode is observed at the beginning and then an asymmetrical buckling mode occurs because of the stress wave superposition.

n order to minimize the precocity and deceit happened in genetic algorithm, this thesis puts forward an improved intelligent evolutionary algorithmcoarse-grained parallel genetic algorithm which proposes schema order based cross operator, task immigration based cross operator, and improved approach for elitist strategy. Also, this paper applies the algorithm into logistic route planning system to clarify the concrete implementation steps for coding, population generation and genetic operator. According to experiment result, the improved algorithm mentioned in this assay have advanced the convergence rate and optimizing ability to some extent.

Cloud computing is a new-type of computing model. This paper deeply expounded the key technology of virtualization and cloud computing through theoretical analysis and practice research on cloud computing and its architecture. Then, it proposed a common cloud computing architecture model based on virtual environment, which consisted of layers of data center, cloud file system, computing model, data management, and application development. In addition, it realized a cloud computing platform based on Hadoop.

Aiming to increase network security auditing efficiency, an audit system with good efficiency has been generated through Agent and log mining technology. This paper improves the traditional association rule mining algorithm Apriori and designs a new data structure in which each brother node is in a parallel alignment, each child node has a pointer directing to their children node and sibling node, the audit system can only scan the database once. Experiments show that compared with traditional Apriori, the improved algorithm has greatly reduced the I/O expenditure of the system, having obvious superiority.

Based on the techniques of dynamic current injection, common source node resonance, second-order linearity performance and the application of CMOS technology, a 1.8V power supply voltage active folding Gilbert-type zero intermediate frequency mixer has been designed by using Candense design system. The result of circuit stimulation shows, single sideband noise figure is 6.109dB when the mixer locates at 1MHz, 6.71dB at 100KHz, 10.631dB at 10KHz. Frequency conversion gain is 11.389dB and input third-order intermodulation point is 4.639dBm.

There are large amount of ammonia in coking wastewater. It is a good recycling desulfurizer. Sintering flue gas has the characteristics, such as large amount of, low SO2 concentration, great changes of operation load. Treating sintering flue gas with coking wastewater can attain the destination of treating waste with waste. This paper adopts a spray tower countercurrent device, and SO2 concentration in the entrance and exit flue gas is on line detected by an automatic flue gas detection instrument. The paper studies on the change rule of SO2 concentration in the process of treating sintering flue gas using coking wastewater, and the influence of SO2 initial concentration in sintering flue gas to the desulfurization rate. The results show that after being treated the sintering flue gas can reach the emission standard for air pollutants of iron and steel industry.