Effects of microstructure characteristics on the tensile properties and fracture toughness of TA15 alloy fabricated by hot isostatic pressing

Powder hot isostatic pressing(HIP) is an effective method to achieve near-net-shape manufacturing of high-quality complex thinwalled titanium alloy parts, and it has received extensive attention in recent years. However, there are few reports about the microstructure characteristics on the strengthening and toughening mechanisms of powder hot isostatic pressed(HIPed) titanium alloys. Therefore, TA15powder was prepared into alloy by HIP approach, which was used to explore the microstructure characteristics at different HIP temperatures and the corresponding tensile properties and fracture toughness. Results show that the fabricated alloy has a “basket-like structure” when the HIP temperature is below 950℃, consisting of lath clusters and surrounding small equiaxed grains belts. When the HIP temperature is higher than 950℃, the microstructure gradually transforms into the Widmanstatten structure, accompanied by a significant increase in grain size. The tensile strength and elongation are reduced from 948 MPa and 17.3% for the 910℃ specimen to 861 MPa and 10% for the 970℃ specimen.The corresponding tensile fracture mode changes from transcrystalline plastic fracture to mixed fracture including intercrystalline cleavage.The fracture toughness of the specimens increases from 82.64 MPa·m^(1/2)for the 910℃ specimen to 140.18 MPa·m^(1/2)for the 970℃ specimen.Specimens below 950℃ tend to form holes due to the prior particle boundaries(PPBs), which is not conducive to toughening. Specimens above 950℃ have high fracture toughness due to the crack deflection, crack branching, and shear plastic deformation of the Widmanstatten structure. This study provides a valid reference for the development of powder HIPed titanium alloy.

市政道路工程中软基加固技术应用

论文以市政道路工程中软基加固技术应用为研究主题,对当前软基地基加固技术在市政工程领域中的应用现状和存在的问题进行深入研究,通过理论分析和实际案例分析,总结了软基地基加固技术的基本原理和技术特点,探讨了其在市政道路工程中的应用现状和发展趋势,提出了相应的解决措施,并对未来的发展进行了展望。论文的研究对提高市政道路工程的质量和效率具有重要意义。

中国湖北汉族重症肌无力与HLA-Ⅱ类等位基因的关联

目的和方法：探讨中国湖北汉族重症肌无力（ＭＧ）患者与ＨＬＡ－Ⅱ类等位基因的关联。利用ＰＣＲ／ＳＳＰ和ＰＣＲ－ＲＦＬＰ技术对湖北地区９１例ＭＧ患者进行ＨＬＡ－Ⅱ类（ＨＬＡ－ＤＲＢ１、ＤＱＢ１和ＤＰＢ１）基因型别分析，并与１６８例正常个体比较。结果：患者组（１）：ＨＬＡ－ＤＲＢ１０９０１、ＤＱＢ１０３０３和ＤＰＢ１０５０１等位基因频率明显高于对照组，ＲＲ值分别为４１２、３０４和３０１，Ｐ＜０．０１；（２）ＨＬＡ－ＤＰＢ１０２０２等位基因频率明显低于对照组，ＲＲ值为０１３，Ｐ＜０．０５。结论：中国湖北汉族群体中ＭＧ与ＨＬＡ－ＤＲＢ１０２０２、等位基因正关联，而与ＨＬＡ－ＤＰＢ１０２０２等位基因呈负关联，与白种人群相比，这种关联对中国湖北汉族ＭＧ病人来说是特有的。

5～6岁儿童执行功能与数学概念发展水平的关系

本研究选取196名5~6岁儿童为研究对象,采用测验法考察其执行功能的抑制控制、工作记忆、认知灵活性三个核心成分与数、量、形、空间及时间5个方面数学概念之间的关系,结果发现5~6岁儿童执行功能发展水平与其数学概念水平之间呈极显著正相关;抑制控制与数、量、形、空间、时间概念都存在正相关;工作记忆与数、空间概念存在正相关;认知灵活性与数、量、空间、时间存在正相关;工作记忆与各数学概念发展水平之间的关系不同于抑制控制和认知灵活性,可能与问题情境和形式有关。教师及家长应重视学前儿童执行功能的培养,关注执行功能水平低的儿童,积极开发能够促进儿童执行功能发展的游戏活动。

重组人脑利钠肽对直接PCI治疗的STEMI患者心功能的影响

目的研究重组人脑利钠肽(rhBNP)对实施直接PCI的STEMI患者心功能的影响。方法 2013年12月-2017年6月在我院就诊的STEMI患者80例,采用随机法分为治疗组和对照组,对照组给予常规治疗+直接PCI;治疗组给予对照组治疗+rhBNP静脉注射。结果两组患者各项基线资料无统计学差异(P>0.05)。rhBNP治疗3 d后,治疗组Killip分级Ⅲ级患者比例(2.5%)低于对照组(17.5%)(P<0.05),Killip分级Ⅳ级患者比例(2.5%)低于对照组(12.5%)(P<0.05);rhBNP治疗结束后,治疗组患者外周静脉血NT-proBNP含量明显升高(20,000 pg/mL-30,000 pg/mL)患者比例(7.5%)明显低于对照组(32.5%)(P<0.05),而NT-proBNP含量正常(200 pg/mL-900 pg/mL)患者比例(52.5%)显著高于对照组(27.5%)(P<0.05),两组患者NT-proBNP含量偏高(901 pg/mL-1,300 pg/mL)患者比例相同(40.0%)(P>0.05)。发病后1个月内,治疗组MACE事件的发生率(5.0%)明显低于对照组(20.0%)(P<0.05)。结论 rhBNP可以保护STEMI患者心功能,减少心衰的发生。

Observer-Based Adaptive Fuzzy Tracking Control Using Integral Barrier Lyapunov Functionals for A Nonlinear System With Full State Constraints

A new fuzzy adaptive control method is proposed for a class of strict feedback nonlinear systems with immeasurable states and full constraints.The fuzzy logic system is used to design the approximator,which deals with uncertain and continuous functions in the process of backstepping design.The use of an integral barrier Lyapunov function not only ensures that all states are within the bounds of the constraint,but also mixes the states and errors to directly constrain the state,reducing the conservativeness of the constraint satisfaction condition.Considering that the states in most nonlinear systems are immeasurable,a fuzzy adaptive states observer is constructed to estimate the unknown states.Combined with adaptive backstepping technique,an adaptive fuzzy output feedback control method is proposed.The proposed control method ensures that all signals in the closed-loop system are bounded,and that the tracking error converges to a bounded tight set without violating the full state constraint.The simulation results prove the effectiveness of the proposed control scheme.

Cavity-induced ATS effect on a superconducting Xmon qubit

We couple a ladder-type three-level superconducting artificial atom to a cavity. Adjusting the artificial atom to make the cavity be resonant with the two upper levels, we then probe the lower two levels of the artificial atom. When driving the cavity to a coherent state, the probe spectrum shows energy level splitting induced by the quantized electromagnetic field in the cavity. This splitting size is related to the coupling strength between the cavity and the artificial atom and, thus, is fixed after the sample is fabricated. This is in contrast to the classical Autler-Townes splitting of a three-level system in which the splitting is proportional to the driving amplitude, which can be continuously changed. Our experiment results show the difference between the classical microwave driving field and the quantum field of the cavity.

Carboxy Cellulose as Cathode Interfacial Layer for Efficient Organic Solar Cells

Green, biodegradable, and eco-friendly interface materials based on cellulose and its derivatives were prepared for organic solar cells(OSCs). In this work, calcium and two derivatives of cellulose with different carboxy acid groups, denoted as Cellulose-COOH and Cellulose-(COOH)n, were used as cathode interfacial layers of OSCs, and a blend of the low-band-gap semiconducting polymers thieno[3, 4-b]thiophene/benzodithiophene(PTB7)and [6, 6]-phenyl C71-butyric acid methyl ester(PC71BM) was chosen as the photoactive layer. OSCs were fabricated with a configuration of indiumdoped tin oxide(ITO)/poly(3, 4-ethylenedioxythiophene) : polystyrene sulfonate(PEDOT: PSS)/PTB7: PC71BM/Ca or Cellulose-COOH or Cellulose-(COOH)n/Al. As a result, the effect of cellulose-COOH was the best one among them, and the power conversion efficiency(PCE) reached 8.21%for the devices with cathode interfacial layer of Cellulose-COOH, which was better than that of OSCs using calcium as a modifier(PCE=7.95%). The favorable performance is attributed to the reduced work function and improved electron transfer caused by the introduction of carboxy cellulose between the active layer and the electrode. The developed technology shows great potential in accelerating the diversified applications of cellulose and producing cost-effective and eco-friendly interfaces for OSCs.

Complementarity via Minimum Error Measurement in a Two-Path Interferometer

We study the fringe visibility and the which-path information(WPI) of a general Mach-Zehnder interferometer with an asymmetric beam splitter(BS). A minimum error measurement in the detector is used to extract the WPI. Both the fringe visibility V and the WPI I_(path) are affected by the initial state of the photon and the second asymmetric BS. The condition in which the WPI takes the maximum is obtained. The complementarity relationship V^2 + I_(path)~2 ≤ 1 is found, and the conditions for equality are also presented.

Fringe visibility and distinguishability in two-path interferometer with an asymmetric beam splitter

We study the fringe visibility and the distinguishability of a general Mach-Zehnder interferometer with an asymmetric beam splitter. Both the fringe visibility V and the distinguishability D are affected by the input state of the particle characterized by the Bloch vector S =(S_x, S_y, S_z) and the second asymmetric beam splitter characterized by the paramterβ. For the total system is initially in a pure state, it is found that the fringe visibility reaches the upper bound and the distinguishability reaches the lower bound when cosβ=-S_x, The fringe visibility obtain the maximum only if S_x = 0 and β = π/2 when the input particle is initially in a mixed state. The complementary relationship V^2 +D^2 ≤ 1 is proved in a general Mach-Zehnder interferometer with an asymmetric beam splitter, and the conditions for the equality are also presented.

CFD-Based Numerical Simulation of Water Film Flash Evaporation with a New Flash Evaporation Model

In this study, a new mass model involving superheat, initial temperature, liquid height, evaporator diameter, and flashing time is established to describe the flash evaporation process of water film. Of 469 sets of flash experimental data from three previous researches, 305 sets were applied to optimize parameters, and the other 164 sets were used to verify the practicability of the model. The results showed that the mean relative error between the literature data and the model values was less than 16.3%, and the model statistics proved that the model was well-posed. Then, the kinetic model was obtained using the time derivative of the new mass model. Computational fluid dynamics simulation of water film flash evaporation was studied based on a user-defined function program of the new evaporation kinetic model. The new kinetic model shows more consistency with the experimental phenomena in terms of evaporated mass and temperature compared with the evaporation–condensation model in Fluent software and Gopalakrishna's model. This new kinetic model can be extended to describe the flash process of water solution under other conditions.

Graph dynamical networks for forecasting collective behavior of active matter

After decades of theoretical studies,the rich phase states of active matter and cluster kinetic processes are still of research interest.How to efficiently calculate the dynamical processes under their complex conditions becomes an open problem.Recently,machine learning methods have been proposed to predict the degree of coherence of active matter systems.In this way,the phase transition process of the system is quantified and studied.In this paper,we use graph network as a powerful model to determine the evolution of active matter with variable individual velocities solely based on the initial position and state of the particles.The graph network accurately predicts the order parameters of the system in different scale models with different individual velocities,noise and density to effectively evaluate the effect of diverse condition.Compared with the classical physical deduction method,we demonstrate that graph network prediction is excellent,which could save significantly computing resources and time.In addition to active matter,our method can be applied widely to other large-scale physical systems.

Infrared light-emitting diodes based on colloidal Pb Se/Pb S core/shell nanocrystals

Colloidal Pb Se nanocrystals(NCs)have gained considerable attention due to their efficient carrier multiplication and emissions across near-infrared and short-wavelength infrared spectral ranges.However,the fast degradation of colloidal Pb Se NCs in ambient conditions hampers their widespread applications in infrared optoelectronics.It is well-known that the inorganic thick-shell over core improves the stability of NCs.Here,we present the synthesis of Pb Se/Pb S core/shell NCs showing wide spectral tunability,in which the molar ratio of lead(Pb)and sulfur(S)precursors,and the concentration of sulfur and Pb Se NCs in solvent have a significant effect on the efficient Pb S shell growth.The infrared light-emitting diodes(IR-LEDs)fabricated with the Pb Se/Pb S core/shell NCs exhibit an external quantum efficiency(EQE)of 1.3%at 1280 nm.The ligand exchange to optimize the distance between NCs and chloride treatment are important processes for achieving high performance on Pb Se/Pb S NC-LEDs.Our results provide evidence for the promising potential of Pb Se/Pb S NCs over the wide range of infrared optoelectronic applications.

3D Multilayered Turtle Shell Models for Image Steganography

By embedding secret data into cover images,image steganography can produce non-discriminable stego-images.The turtle shell model for data hiding is an excellent method that uses a reference matrix to make a good balance between image quality and embedding capacity.However,increasing the embedding capacity by extending the area of basic structures of the turtle shell model usually leads to severe degradation of image quality.In this research,we innovatively extend the basic structure of the turtle shell model into a three-dimensional(3D)space.Some intrinsic properties of the original turtle shell model are well preserved in the 3D version.Theoretic analysis shows that the new proposed models have good performance both in the image quality and in the complexity of the reference matrix.Our experimental results justify the theoretic conclusions.

A Mathematical Model of Heat Transfer in Problems of Pipeline Plugging Agent Freezing Induced by Liquid Nitrogen

A mathematical model for one-dimensional heat transfer in pipelines undergoing freezing induced by liquid nitrogen is elaborated.The basic premise of this technology is that the content within a pipeline is frozen to form a plug or two plugs at a position upstream and downstream from a location where work a modification or a repair must be executed.Based on the variable separation method,the present model aims to solve the related coupled heat conduction and moving-boundary phase change problem.An experiment with a 219 mm long pipe,where water was taken as the plugging agent,is presented to demonstrate the relevance and reliability of the proposed model(results show that the error is within 18%).Thereafter,the model is applied to predict the cooling and freezing process of pipelines with different inner diameters at different liquid nitrogen refrigeration temperatures when water is used as the plugging agent.

Effects of short-range attraction on Jamming transition

Enormous progresses to understand the jamming transition have been driven via simulating purely repulsive particles which were somehow idealized in the past two decades. While the attractive systems are both theoretical and practical compared with repulsive systems. By studying the statistics of rigid clusters, we find that the critical packing fraction φ_(c) varies linearly with attraction μ for different system sizes when the range of attraction is short. While for systems with long-range attractions, however, the slope of φ_(c) appears significantly different, which means that there are two distinct jamming scenarios. In this paper, we focus our main attention on short-range attractions scenario and define a new quantity named "short-range attraction susceptibility" χ_(p), which describes the degree of response of the probability of finding jammed states pjto short-range attraction strength μ. Our central results are that χ_(p) diverges in the thermodynamic limit as χ_(p) ∝|φ-φ_(c)^(∞)|^(-γ_(p)), where φ_(c)^(∞) is the packing fraction at the jamming transition for the infinite system in the absence of attraction. χ_(p) obeys scaling collapse with a scaling function in both two and three dimensions, illuminating that the jamming transition can be considered as a phase transition as proposed in previous work.

Friable Callus Induction of Hedera nepalensis var.sinensis

[Objectives]The purpose was to establish an induction system for friable callus of Hedera nepalensis var.sinensis with different parts.[Methods]By screening the most suitable explant and adjusting the hormone ratio of medium,friable calli of H.nepalensis var.sinensis were induced.[Results]The calli could be induced from leaves,petioles and stem segments,but the ideal explant was stem segments,with induction rate reaching 98%.The optimal medium for callus proliferation was MS+0.5 mg/L KT+1.0 mg/L 2,4-D+30.0 g/L sucrose.After 3-4 generations of subculture on MS+0.5 mg/L BA+1.0 mg/L 2,4-D+30.0 g/L sucrose,favorable friable calli of H.nepalensis var.sinensis were obtained.[Conclusions]The friable calli induced in this experiment can lay a foundation for in-vitro regeneration and cellular secondary metabolite production of H.nepalensis var.sinensis.

Study on Tissue Culture and Rapid Propagation of Platycodon grandiflorus

With seeds as experimental materials,MS was used as the basic medium to combine different species and concentrations of auxin and mitogen for proliferation,elongation and rooting culture. The best combination of medium and the most suitable medium were selected. The results showed that the best formula for the medium was MS + 0. 5 mg/L BA + 0. 5 mg/L IAA + 30 g/L sucrose in the proliferation culture,MS + 0. 25 mg/L BA + 0. 5 mg/L IAA + 30 g/L sucrose in the elongation culture,and MS + 0. 5 mg/L IAA + 20 g/L sucrose in the rooting culture respectively. The experimental results will be applied in the rapid propagation and breeding of high-quality seedlings of Platycodon grandiflorus.

Study on Social Service Transformation of New Established Undergraduate Institutions in China: Based on Text Analysis on News on Official Website

The transformation of social services is one of the key tasks for the undergraduate university changing to be an applied university. This article made a text analysis on the news about social service from the column of "university events”. It shows that the social service of newly-building undergraduate university has distinctive features and has an orientation of "localness, application, openness”, which is a natural advantage. It also has the following problems: too many plans lacking systematicness, core competence and sense of participation, lower service level, out-of-date philosophy and so on. It is suggested that newly-building undergraduate university make an inner-driven transformation, with direct and active service to others.

Research for Merger and Acquisition of Petrochemical Industries Based on Value Chain

Based on the analysis of the theories of value chain and multinational merger and acquisition, we research the merger and acquisition of petrochemical industries based on value chain, according to the trait of the value chain of the petrochemical industries. And we propose the implementation process and the integration method for the merger and acquisition of petrochemical industries based on value chain.