Flow characteristics and hot workability of a typical low-alloy high-strength steel during multi-pass deformation

Heavy components of low-alloy high-strength(LAHS) steels are generally formed by multi-pass forging. It is necessary to explore the flow characteristics and hot workability of LAHS steels during the multi-pass forging process, which is beneficial to the formulation of actual processing parameters. In the study, the multi-pass hot compression experiments of a typical LAHS steel are carried out at a wide range of deformation temperatures and strain rates. It is found that the work hardening rate of the experimental material depends on deformation parameters and deformation passes, which is ascribed to the impacts of static and dynamic softening behaviors. A new model is established to describe the flow characteristics at various deformation passes. Compared to the classical Arrhenius model and modified Zerilli and Armstrong model, the newly proposed model shows higher prediction accuracy with a confidence level of 0.98565. Furthermore, the connection between power dissipation efficiency(PDE) and deformation parameters is revealed by analyzing the microstructures. The PDE cannot be utilized to reflect the efficiency of energy dissipation for microstructure evolution during the entire deformation process, but only to assess the efficiency of energy dissipation for microstructure evolution in a specific deformation parameter state.As a result, an integrated processing map is proposed to better study the hot workability of the LAHS steel, which considers the effects of instability factor(IF), PDE, and distribution and size of grains. The optimized processing parameters for the multi-pass deformation process are the deformation parameters of 1223–1318 K and 0.01–0.08 s^(-1). Complete dynamic recrystallization occurs within the optimized processing parameters with an average grain size of 18.36–42.3 μm. This study will guide the optimization of the forging process of heavy components.

Deciphering the chromatin spatial organization landscapes during BMMSC differentiation

The differentiation imbalance in bone marrow mesenchymal stem cells(BMMSCs)is critical for the development of bone density diseases as the population ages.BMMSCs are precursor cells for osteoblasts and adipocytes;however,the chromatin organization landscapes during BMMSC differentiation remain elusive.In this study,we systematically delineate the four-dimensional genome and dynamic epigenetic atlas of BMMSCs by RNA sequencing,assay for transposase-accessible chromatin sequencing,and highthroughput chromosome conformation capture.The structure analyses reveal 17.5%common and28.5%-30%specific loops among BMMSCs,osteoblasts,and adipocytes.The subsequent correlation of genome-wide association studies and expression quantitative trait locus(e QTL)data with multi-omics analysis reveal 274 genes and 3634 single nucleotide polymorphisms(SNPs)associated with bone degeneration and osteoporosis(OP).We hypothesize that SNP mutations affect transcription factor(TF)binding sites,thereby affecting changes in gene expression.Furthermore,26 motifs,260 TFs,and 291SNPs are identified to affect the e QTL.Among these genes,DAAM2,TIMP2,and TMEM241 are found to be essential for diseases such as bone degeneration and OP and may serve as potential drug targets.

Three Dimensional Metal-Surface Processing Parameter Generation Through Machine Learning-Based Nonlinear Mapping

The accuracy and efficiency of three-dimensional(3D)surface forming,which directly affects the cycle and quality of production,is important in manufacturing.In practice,given the uncertainty of metal plate springback,an error exists between the actual plate and the target surface,which creates a nonlinear mapping from computer aided design models to bending surfaces.Technicians need to reconfigure parameters and process a surface multiple times to delicately control springback,which greatly wastes human and material resources.This study aims to address the springback control problem to improve the efficiency and accuracy of sheet metal forming.A basic computation approach is proposed based on the DeepFit model to calculate the springback value in 3D surface bending.To address the sample data shortage problem,we put forward an advanced approach by combining a deep learning model with case-based reasoning(CBR).Next,a multi-model fused bending parameter generation framework is devised to implement the advanced springback computation approach through surface data preprocessing,CBR-based model matching,convolution neural network-based machining surface generation,and bending parameter generation with a series of model transformations.Moreover,the proposed approaches and the framework are verified by considering saddle surface processing as an example.Overall,this study provides a new idea to improve the accuracy and efficiency of surface processing.

SrAl2O4：Eu^2＋，Dy^3＋的气压敏感余辉发光性能研究

本文对长余辉材料SrAl_2O_4:Eu^2+,Dy^3+在较低气体压力(0~300000 Pa)影响下的余辉强度变化情况进行了系统地研究,发现对于相同的气体压力,余辉亮度的响应情况随加压时间点的改变不同,且在100~260 s之间灵敏度随开始时间的延后而增加,具有较好的规律性.在0~300000 Pa压力范围内SrAl_2O_4:Eu^2+,Dy^3+的余辉强度变化情况与气体压力变化值线性相关且灵敏度较高.我们认为,SrAl_2O_4:Eu^2+,Dy^3+作为新型压敏发光材料在非接触测压领域具有良好的应用前景.

酿酒酵母代谢工程技术

自20世纪90年代初期诞生以来,代谢工程历经了30年的快速发展。作为代谢工程的首选底盘细胞之一,酿酒酵母细胞工厂已被广泛应用于大量大宗化学品和新型高附加值生物活性物质的生物制造,在能源、医药和环境等领域取得了巨大的突破。近年来,合成生物学、生物信息学以及机器学习等相关技术也极大地促进了代谢工程的技术发展和应用。文中回顾了近30年来酿酒酵母代谢工程重要的技术发展,首先总结了经典代谢工程的常用方法和策略,以及在此基础上发展而来的系统代谢工程和合成生物学驱动的代谢工程技术。最后结合最新技术发展趋势,展望了未来酿酒酵母代谢工程发展的新方向。

Rational design and evaluation of UV curable nano-silver ink applied in highly conductive textile-based electrodes and flexible silver-zinc batteries

The possibility of printing conductive ink on textiles is progressively researched due to its potential benefits in manufacturing functional wearable electronics and improving wearing comfort.However,few studies have reported the effect of conductive ink formulation on electrodes directly screen-printed on flexible substrates,especially printing UV curable conductive ink on common textiles.In this work,a novel UV curable nano-silver ink with short-time curing and low temperature features was developed to manufacture the fully flexible and washable textile-based electrodes by screen printing.The aim of this study was to determine the influence of ink formulation on UV-curing speed,degree of conversion,morphology and electrical properties of printed electrodes.Besides,the application demonstration was highlighted.The curing speed and adhesion of ink was found depending dominantly on the type of prepolymer and the functionality of monomer,and the type of photoinitiator had a decisive effect on the curing speed,degree of double bond conversion and morphology of printed patterns.The nano-silver content is key to guarantee the suitable screen-printability of conductive ink and therefore the uniformity and high conductivity of textile-based electrodes.Optimally,an ink formulation with 60 wt%nano-silver meets the potential application requirements.The electrode with 1.0 mm width showed significantly high electrical conductivity of 2.47×10^(6)S/m,outstanding mechanical durability and satisfactory washability.The high-performance of electrodes screen-printed on different fabrics proved the feasibility and utility of UV curable nano-silver ink.In addition,the application potential of the conductive ink in fabricating electronic textiles(e-textiles)was confirmed by using the textile-based electrodes as the cathodes of silverzinc batteries.We anticipate the developed UV curable conductive ink for screen-printing on textiles can provide a novel design opportunity for flexible and wearable e-textile applications.

Development of synthetic biology tools to engineer Pichia pastoris as a chassis for the production of natural products

The methylotrophic yeast Pichia pastoris(a.k.a.Komagataella phaffii)is one of the most commonly used hosts for industrial production of recombinant proteins.As a non-conventional yeast,P.pastoris has unique biological characteristics and its expression system has been well developed.With the advances in synthetic biology,more efforts have been devoted to developing P.pastoris into a chassis for the production of various high-value compounds,such as natural products.This review begins with the introduction of synthetic biology tools for the engineering of P.pastoris,including vectors,promoters,and terminators for heterologous gene expression as well as Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated System(CRISPR/Cas)for genome editing.This review is then followed by examples of the production of value-added natural products in metabolically engineered P.pastoris strains.Finally,challenges and outlooks in developing P.pastoris as a synthetic biology chassis are prospected.

Preparation and luminescence properties of orange-red Ba3Y4O9:Sm3+phosphors

A novel orange-red emitting Ba3 Y4 O9：Sm^（3＋） phosphors were prepared by a high temperature solidstate reaction in air. X-ray diffraction（XRD）, photoluminescence spectra, fluorescence decay and temperature-dependent emission spectra were utilized to characterize the structure and luminescence properties. The results show that the excitation spectrum includes a series of linear peaks at350, 367, 382, 410, 424, 445, 470 and 495 nm, respectively. Under 410 nm excitation, the emission peaks were located at 574 nm（~4 G（5/2）-~6 H（5/2））, 608 nm（~4 G（5/2）-~6 H（7/2））,659 nm（~4 G（5/2）-~6 H（9/2）） and722 nm（~4 G（5/2）-~6 H（11/2））, respectively. The concentration quenching occurs when x equals 0.08 for Ba3 Y（4-x）O9：xSm^（3＋） phosphor and its mechanism is ascribed to the dipole-dipole interaction. The chromaticity coordinates of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor are in the orange-red region. The temperature-dependent study shows that this phosphor has excellent luminescence thermal-stability.And the luminescence intensity of Ba3 Y（3.92）O9：0.08 Sm^（3＋） phosphor at 473 K only declines by about25.75% of its initial intensity. The experimental data indicate that Ba3 Y4 O9：Sm^（3＋） phosphor may be promising as an orange-red emitting phosphor for white light emitting diodes.

Eu^(3+)-doped BaLiZn_(3)(BO_(3))_(3):A novel red-emitting phosphor for blue chips excited white LEDs

A series of novel red-emitting BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors were synthesized through the high temperature solid state reaction method.The phase composition,crystal structure,morphology and photo luminescence property of the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)samples were systematically investigated.The phosphor can be efficiently excited by the near ultraviolet light(NUV)of 396 nm and blue light of 466 nm,and give out red light emission at 618 nm corresponding to the electric dipole transition(^(5)D_(0)→^(7)E_(2)).The optimal doping concentration of Eu^(3+)ions in BaLiZn_(3)(BO_(3))_(3)is determined to be about 3 mol%,and the concentration-quenching phenomenon arise from the electric dipole-dipole interaction.The temperature dependent luminescence behavior of BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)phosphor exhibits its good thermal stability,and the activation energy for thermal quenching characteristics is calculated to be 0.1844 eV.The decay lifetime of the BaLiZn_(3)(BO_(3))_(3):0.03 Eu^(3+)is measured to be 1.88 ms.These results suggest that the BaLiZn_(3)(BO_(3))_(3):Eu^(3+)phosphors have the potential application as a red component in white light emitting diodes(WLEDs)with NUV or blue chips.

Synthesis,structure and optical properties of novel thermally robust Dy^(3+)-doped Ca_(9)Sc(PO_(4))_(7) phosphors for NUV-excited white LEDs

The powder samples of Ca_(9)Sc(PO_(4))_(7):xDy^(^(3+))white emitting phosphors were prepared via a solid state reaction technique.The Ca_(9)Sc(PO_(4))_(7):Dy^(3+)samples were researched by using the GSAS Rietveld refinement and X-ray diffraction(XRD) methods,and SEM images and elemental maps were recorded.Under 350 nm excitatio n,the emission spectra of Ca_(9)Sc(PO_(4))_(7):xDy^(3+)samples have two obvious peaks and one weak peak at 484,572 and660 nm,corresponding to the characteristic electron transitions of(^(4)F_(9/2)→ ^(6)H_(15/2),blue),(^(4)F_(9/2)→ ^(6)H_(13/2),yellow) and(^(4)F_(9/2)→ 6 H11/2,red),respectively.The concentration quenching effect,decay lifetime and thermal quenching of the as-synthesized Ca_(9)Sc(PO_(4))_(7):Dy^(3+)samples were researched systematically.The Ca_(9)Sc(PO_(4))_(7):0.02 Dy^(3+)phosphor possesses a good thermal stability,of which the emission intensity at 423 K can maintain 79% of the initial value(273 K).In addition,through the study of the chro maticity coordinates of the Ca_(9)Sc(PO_(4))_(7):0.02 Dy^(3+)phosphor,it is found that it is located in the white region,and the Commission Internationalede L’Eclairage(CIE) chromaticity coordinates are(0.339,0.389),The above results show that Ca_(9)Sc(PO_(4))_(7):xDy^(3+)phosphors can be excellent candidate material for applications in NUV-excited white LEDs.

Cell-free protein synthesis enabled rapid prototyping for metabolic engineering and synthetic biology

Advances in metabolic engineering and synthetic biology have facilitated the manufacturing of many valuable-added compounds and commodity chemicals using microbial cell factories in the past decade.However,due to complexity of cellular metabolism,the optimization of metabolic pathways for maximal production represents a grand challenge and an unavoidable barrier for metabolic engineering.Recently,cell-free protein synthesis system(CFPS)has been emerging as an enabling alternative to address challenges in biomanufacturing.This review summarizes the recent progresses of CFPS in rapid prototyping of biosynthetic pathways and genetic circuits(biosensors)to speed up design-build-test(DBT)cycles of metabolic engineering and synthetic biology.

Platelet donor database:a study on the specialist donor database for the patients with alloimmune thrombocytopenia in the Chinese population and the assessment of completeness

To the Editor:Due to the immunogenicity of the platelet antigens,especially blood group antigen(such as ABO antigens),human leukocyte antigen(HLA),human platelet antigen(HPA),and CD36(platelet glycoproteins IV),which can produce corresponding alloantibodies through immune factors such as blood transfusion,pregnancy,and drugs,the immune reaction of the platelet antigens and antibodies in patients will lead to various types of alloimmune thrombocytopenia.

A linked data-based approach for clinical treatment selecting support

Treatment plan selection is a complex process because it sometimes needs sufficient experience and clinical information.Nowadays it is even harder for doctors to select an appropriate treatment plan for certain patients since doctors might encounter difficulties in obtaining the right information and analyzing the diverse clinical data.In order to improve the effectiveness of clinical decision making in complicated information system environments,we first propose a linked data-based approach for treatment plan selection.The approach integrates the patients’clinical records in hospitals with open linked data sources out of hospitals.Then,based on the linked data net,treatment plan selection is carried on aided by similar historical therapy cases.Finally,we reorganize the electronic medical records of 97 colon cancer patients using the linked data model and count the similarity of these records to help treatment selecting.The experiment shows the usability of our method in supporting clinical decisions.

Single-phase white-emitting and tunable color phosphor Na_(3)Sc_(2)(PO_(4))_(3):Eu^(2+),Dy^(3+): Synthesis, luminescence and energy transfer

A series of Eu^(2+)/Dy^(3+) single doped and co-doped Na_(3)Sc_(2)(PO_(4))_(3) phosphors were synthesized by the high-temperature solid-state method,and their phase,morphology,and luminescence properties were characterized.Under the excitation of 370 nm,the Na_(3)Sc_(2)(PO_(4))_(3):Eu^(2+),Dy^(3+) phosphor can emit white light whose spectrum is composed of a broad emission band centered at 460 nm and the other three peaks at 483,577,and 672 nm,respectively.There is energy transfer from Eu^(2+)to Dy^(3+)ion in Na_(3)Sc_(2)(PO_(4))_(3):Eu^(2+),Dy^(3+) phosphor due to the good overlap between the emission spectrum of Na_(3)Sc_(2)(PO_(4))_(3):Eu^(2+) and the excitation spectrum of Na_(3)Sc_(2)(PO_(4))_(3):Dy^(3+),which is further confirmed by the fluorescence lifetime decrease of Eu^(2+)ion with the increase of Dy^(3+) concentration.The process of energy transfer is via dipole–quadruple interaction which is confirmed by applying Dexter's theory.By increasing the Dy^(3+)concentration,the color coordinates of the Na_(3)Sc_(2)(PO_(4))_(3):0.01Eu^(2+),xDy^(3+)phosphors can be adjusted from blue to white,and then to yellow.The optimized concentration of Dy^(3+)ions is 4.0 mol%,beyond which the concentration quenching will take place.The Na_(3)Sc_(2)(PO_(4))_(3):Eu^(2+),Dy^(3+)phosphor shows fairly good resistance to thermal quenching behavior,of which the emission intensity at 423 K can maintain 90.3%of the initial value(298 K).These results suggest that the Na_(3)Sc_(2)(PO_(4))_(3):0.01Eu^(2+),xDy^(3+)phosphors have potential applications as the color-tunable or a single-phase white emitting phosphor in white LEDs.