基于FPGA的VGA图像控制器设计

首先介绍了VGA图像控制器的硬件电路,然后分别从时序信号产生、图片数据的存储和图像显示三个方面对VGA图像控制器的软件部分进行了介绍,最后给出了该控制器在ModelS im中的仿真结果并指出了该设计的可行性及优越性。     

65Mn宽钢带冷轧边裂原因分析及预防

利用金相观察、硬度检测等手段对65Mn宽钢带冷轧过程出现的边裂问题进行了原因分析和研究。结果表明:65Mn钢热轧原料组织为铁素体+珠光体,但由于在热轧水冷过程中边部冷却速度比中间快,珠光体组织片层相对更细。在两相区球化退火过程中,边部较细的珠光体组织更容易被脆性较大的粗珠光体组织所取代。在相对较大的冷轧压下率条件下,造成边部出现裂口。将一次退火工艺由两相区球化退火优化调整为亚温球化退火后,65Mn钢带边部组织球化率显著提高,基本避免了边裂情况的产生,并为实际工业生产提供了积极的指导作用。     

Investigation on mechanical properties and corrosion behavior of dissimilar joints of 5083 and 6005A alloy welded by friction stir welding

In this paper, the microstructure, mechanical properties, and corrosion behavior of friction stir welded (FSW) joints of the two aluminum alloys 6005A-5083 were investigated and their correlation was discussed. In contrast to FSW joints of the same aluminum material, this results in a “V” shape curve of hardness distributed nonsymmetrically along the weld. The lowest hardness area occurs at the interface between the heat-affected zone and the thermo-mechanically affected zone of 6005A (6-HAZ and 6-TMAZ) due to the transformation of the β" phase under the influence of heat input during the stir friction process. This also leads to all tensile specimens fracturing in this area. The corrosion behavior of the FSW joint in acidic solution containing Cl⁻ was determined by an exfoliation corrosion (EXCO) test, an intergranular corrosion (IGC) test, and potentiodynamic polarization measurements, based on the potential application in acid rain environment. The results showed that the corrosion resistance order in the acidic solution is: 6-HAZ > NZ > 6-BM > 5-HAZ > 5-BM. The 5-BM has the worst corrosion resistance due to the high corrosion sensitivity of Al₃Mg₂ in acidic solution. However, good corrosion resistances are shown in NZ and 6-HAZ, which is related to a relatively homogeneous microstructure in NZ and a dissolution or coarsening of β" phases in 6-HAZ because of frictional heat input.     

An effective data placement strategy for IIoT applications

With the rapid development of the Internet of things (IoT) and mobile communication technology, the amount of data related to industrial Internet of things (IIoT) applications has shown a trend of explosive growth, and hence edge-cloud collaborative environment becomes one of the most popular paradigms to place the IIoT applications data. However, edge servers are often heterogeneous and capacity limited while having lower access delay, so there is a contradiction between capacity and latency while using edge storage. Additionally, when IIoT applications deployed crossing edge regions, the impact of data replication and data privacy should not be ignored. These factors often pose challenges to proposing an effective data placement strategy to take full advantage of edge storage. To address these challenges, an effective data placement strategy for IIoT applications is designed in this article. We first analyze the data access time and data placement cost in an edge-cloud collaborative environment, with the consideration of data replication and data privacy. Then, we design a data placement strategy based on $$-constraint and Lagrangian relaxation, to reduce the data access time and meanwhile limit the data placement cost to an ideal level. As a result, our proposed data placement strategy can effectively reduce data access time and control data placement costs. Simulation and comparative analysis results have demonstrated the validity of our proposed strategy.     

复合盐酸酸洗液在钢丝热镀锌生产中的应用

常温盐酸酸洗能耗小,对钢丝基体腐蚀性小,酸雾少,但去除铁锈和氧化皮速度较慢。盐酸酸洗液浓度较高时,酸雾逸出多,给生产环境造成了污染;同时对钢丝基体造成过腐蚀,易形成钢丝氢脆现象。在试验的基础上,优选出一种常温复合盐酸除锈酸洗液配方及浓度控制范围。生产使用结果表明,添加TX-10、SLS活性剂,含羧酸有机添加剂和磷酸都有利于提高酸洗速度,同时起到了抑制酸雾的逸出及其对钢丝的过腐蚀作用。     

Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system (water+1,6-diaminohexane+2-methyl-1-propanol) and (water+1,6-diaminohexane+3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient (D) and selectivity (S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models. The percent-root-mean-square deviation (RMSD) values for NRTL and UNIQUAC models were less than 0.15, which indicated that the experimental data have been sufficiently correlated.     

Accelerated methane storage in clathrate hydrates using surfactantstabilized suspension with graphite nanoparticles

In this study, enhanced kinetics of methane hydrate formation in the sodium dodecyl sulfate(SDS) solution with different concentrations of suspended graphite nanoparticles(GNPs) were investigated at 6.1–9.0 MPa and 274.15 K. The GNPs with rough surfaces and excellent thermal conductivity not only provided a considerable number of microsites for hydrate nucleation but also facilitated the fast hydrate heat transfer in the suspension system. At a relatively low pressure of 6.1 MPa, the suspension with 0.4 wt% of GNPs exhibited the minimum induction time of 22 min and maximum methane uptake of 126.1 cm~3·cm~(-3). However, the methane storage performances of the suspensions with higher and lower concentrations of GNPs were not satisfactory. At the applied pressure, the temperature increase arising from the hydrate heat in the suspension system with the optimized concentration(0.4 wt%) of GNPs was more significant than that in the traditional SDS solution. Furthermore,compared with those of the system without GNPs, enhanced hydration rate and storage capacity were achieved in the suspensions with GNPs, and the storage capacities were increased by 3.9%–17.0%. The promotion effect of GNPs on gas hydrate formation at low pressure is much more obvious than that at high pressure.     

Structure and electrically conductive properties of porous PAN-based nanocomposites prepared by Pickering emulsion template method

A carbon nanohybrid Pickering stabilizer was synthesized by the hydrothermal reaction of 2-ethyl-4-methylimidazole (EMI), graphene oxide (GO), and carbon nanotubes (CNTs). A water-in-oil (w/o) type Pickering emulsion was achieved using the mixed carbon nanohybrids/Span 80 to form a porous and conductive polyacrylonitrile (PAN) nanocomposites after polymerization. Contact angle and X-ray photoelectron spectroscopy (XPS) results show that the carbon nanohybrid stabilizer is amphiphilic. The effects of the composition and concentration of stabilizers were investigated. When the concentration of the carbon nanohybrid stabilizer is 4 mg ml⁻¹, the conductivity of the resulting material is 2.31 × 10⁻⁹ S m⁻¹, which is six orders of magnitude higher than that of porous PAN composites without carbon nanohybrid stabilizer. At the mass ratio of 6GO:1CNTs, the conductivity of porous PAN-based composites reaches 2.47 × 10⁻⁸ S m⁻¹. The significantly increased conductivity is the evidence for the three dimensional conductive network constructed by carbon nanohybrid stabilizer at the oil/water interface.     

Expression and characterization of a CALB-type lipase from Sporisorium reilianum SRZ2 and its potential in short-chain flavor ester synthesis

A lipase from Sporisorium reilianum SRZ2 (SRL) with 73% amino acid sequence identity to Candida antarctica lipase B (CALB) was cloned and overexpressed in Pichia pastoris. The recombinant SRL showed a preference for short-chain p-nitrophenyl esters. It achieved maximum activity at pH 8.0 and 65°C for p-nitrophenyl hexanoate (C6) with K_m and k_cat/K_m values of 0.14 mmol∙L⁻¹ and 1712 min⁻¹∙mmol∙L₋₁ at 30°C, respectively. SRL displayed excellent thermostability and pH stability, retaining more than 79% of its initial activity after incubation at 60°C for 72 h and 75% at pH 3 to 11 for 72 h. It also maintained most of its activity in the presence of inhibitors and detergents except sodium dodecyl sulfate, and it tolerated organic solvents. SRL was covalently immobilized and successfully used for ethyl hexanoate synthesis in cyclohexane or in a solvent-free system with a high conversion yield (>95%). Furthermore, high conversion yield was also achieved for the synthesis of various short-chain flavor esters when high substrate concentrations of 2 mol∙L⁻¹ were applied. This study indicated that a CALB-type lipase from S. reilianum SRZ2 showed great potential in organic ester synthesis.     

煤矿密闭采空区CO异常涌出治理实践

针对某煤矿644探巷及五盘区发生CO异常涌出事件,通过监测分析CO涌出位置和浓度,初步判定CO由2214柱式工作面异常涌出,煤柱裂隙吸附氧气加快煤氧化,密封巷启封回收设备和密闭采空区漏风使煤氧化自燃,导致CO异常涌出。通过采取全面监控、均压调风、加固密闭墙、注氮的治理措施,异常涌出位置的CO浓度由超过1 000×10-6降低至200×10-6左右,有效地控制了封闭区内煤炭氧化速率,避免了更严重的事故发生。