基于河北省5个主产县的玉米生产技术效率分析

玉米是河北省第一大粮食作物,技术效率对保持生产力至关重要。本文以2012—2018年河北省宁晋县、大名县等5个主产县170个玉米种植户投入-产出数据为基础,利用DEA研究方法分析了河北省玉米生产技术效率的发展变化。结果表明:各县玉米生产综合技术效率、纯技术效率、规模效率平均值分别为0.822、0.989、0.832。其中,玉田县和大名县玉米综合技术效率不高,全要素生产率未达到有效前沿,规模效率呈下降趋势。针对分析结果,从适度规模经营、科学合理分配投入要素等方面提出相应的对策建议。

宁波市某废弃矿山地质环境恢复治理研究

以宁波市某废弃矿山为例,结合矿山的地质环境条件进行了恢复与治理。通过山体边坡生态环境治理工程的实施,基本消除了矿山安全隐患,在确保边坡稳定的基础上采取因地制宜的绿化措施,逐步恢复和重建矿山的生态环境。结果表明:通过对矿山生态环境的治理,可以有效地解决山体边坡的诸多安全和环境问题。

Enhanced Hole-Injection Property in an OLED with a Self-assembled Monolayer of Hole-Transporting TPD on Thin Au as the Anode

A thioester-functionalized triphenylamine hole-transporting molecule(TPD-SAc) was synthesized and self-assembled to form a monolayer on an ultra-thin Au film supported on indium-tin oxide glass. The modified surface was characterized by aqueous contact angle, ellipsometer, atomic force microscopy, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectrometer to substantiate the formation of compact and pinhole-free monolayers. The modified organic light emitting diode device [indium-tin oxide/Au(5 nm)/self-assembled monolayers(SAM)/TPD(50 nm)/Alq_3(40 nm)/TPBI(15 nm)/LiF(1 nm)/Al(100 nm)] showed a luminance of 7303.90 cd/m^2 and a current efficiency of 8.49 cd/A with 1.78 and 2.29-fold increase, respectively, compared to the control device without SAM. The improvements were attributed to the enhanced compatibility of the organic–inorganic interface, matched energy level by introduction of an energy mediating step and superior hole-injection property of SAM molecules.

Multidisciplinary team management and long-term prognosis of an elderly patient with severe cardiac amyloidosis complicated with multiple myeloma

Immunoglobulin light chain amyloidosis(AL)is one of the most frequent causes of cardiac amyloidosis(CA),[1]with an estimated prevalence of 8 to 12 per million.[2−4]Multiple myeloma(MM)is hematological neoplasia originating from plasma cells,which is the most common disease that can lead to CA.The median age of patients with MM at diagnosis is about 65 years old.In this age group,cardiovascular diseases often co-exist,increasing the risk of adverse events related to MM treatment.By convention,the prognosis of AL-CA with MM is extremely poor,with a median survival time of five months.[5]The degree of cardiac involvement has a decisive impact on the prognosis of AL-CA pati-ents.

Early identification of STEMI patients with emergency chest pain using lipidomics combined with machine learning

OBJECTIVES To analyze the differential expression of lipid spectrum between ST-segment elevated myocardial infarction(STEMI)and patients with emergency chest pain and excluded coronary artery disease(CAD),and establish the predictive model which could predict STEMI in the early stage.METHODS We conducted a single-center,nested case-control study using the emergency chest pain cohort of Peking Univer-sity Third Hospital.Untargeted lipidomics were conducted while LASSO regression as well as XGBoost combined with greedy algorithm were used to select lipid molecules.RESULTS Fifty-two STEMI patients along with 52 controls were enrolled.A total of 1925 lipid molecules were detected.There were 93 lipid molecules in the positive ion mode which were differentially expressed between the STEMI and the control group,while in the negative ion mode,there were 73 differentially expressed lipid molecules.In the positive ion mode,the differentially expressed lipid subclasses were mainly diacylglycerol(DG),lysophophatidylcholine(LPC),acylcarnitine(CAR),lysophospha-tidyl ethanolamine(LPE),and phosphatidylcholine(PC),while in the negative ion mode,significantly expressed lipid subclasses were mainly free fatty acid(FA),LPE,PC,phosphatidylethanolamine(PE),and phosphatidylinositol(PI).LASSO regression se-lected 22 lipids while XGBoost combined with greedy algorithm selected 10 lipids.PC(15:0/18:2),PI(19:4),and LPI(20:3)were the overlapping lipid molecules selected by the two feature screening methods.Logistic model established using the three lipids had excellent performance in discrimination and calibration both in the derivation set(AUC:0.972)and an internal validation set(AUC:0.967).In 19 STEMI patients with normal cardiac troponin,18 patients were correctly diagnosed using lipid model.CONCLUSIONS The differentially expressed lipids were mainly DG,CAR,LPC,LPE,PC,PI,PE,and FA.Using lipid molecules selected by XGBoost combined with greedy algorithm and LASSO regression to establish model could accurately predict STEMI even in the more earlier stage.

3D DSMC Simulation of Rarefied Gas Flows around a Space Crew Capsule Using OpenFOAM

An open source Direct Simulation Monte Carlo (DSMC) code, called as dsmcFoam in OpenFOAM, is used to study a blunt body with the shape of a space crew capsule return vehicle. The rarefied gas has the Knudsen number with 0.03. The flow with a Mach number 4.35 over the capsule was simulated by DSMC. The distributions of velocity field and temperature around the capsule were calculated. This study may provide some useful information for the reentry of the return vehicle.

Coaxial electrospinning core-shell fibers for self-healing scratch on coatings

Polystyrene(PS) fibers with core-shell structures were fabricated by coaxial electrostatic spinning,[10_TD$IF]in which there are liquid epoxy or curing agent as the core and PS as the shell. Scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectra and optical microscope were utilized for charactering the morphology and composition of the fibers. Composite coatings embedded with the healant-loaded coreshell fibers have been prepared and the self-healing of the scratch on the coatings has been revealed.

High performance computing for flood simulation using Telemac based on hybrid MPI/OpenMP parallel programming

Usually simulations on environment flood issues will face the scalability problem of large scale parallel computing.The plain parallel technique based on pure MPI is difficult to have a good scalability due to the large number of domain partitioning.Therefore,the hybrid programming using MPI and OpenMP is introduced to deal with the issue of scalability.This kind of parallel technique can give a full play to the strengths of MPI and OpenMP.During the parallel computing,OpenMP is employed by its efficient fine grain parallel computing and MPI is used to perform the coarse grain parallel domain partitioning for data communications.Through the tests,the hybrid MPI/OpenMP parallel programming was used to renovate the finite element solvers in the BIEF library of Telemac.It was found that the hybrid programming is able to provide helps for Telemac to deal with the scalability issue.

Parallelization of Lattice Boltzmann method using MPI domain decomposition technology for a drop impact on a wetted solid wall

Lattice Boltzmann method(LBM)is a new attractive computational approach for simulating isothermal multi-phase flows in computational fluid dynamics(CFD).It is based on the kinetic theory and easy to be parallelized.This study aims to analyze the performance of parallel LBM programming for the incompressible two-phase flows at high density and viscosity ratio.For this purpose,a liquid drop impact on a wetted wall with a pre-existing thin film of the same liquid is simulated by using the parallel LBM code.During the simulations,the domain decomposition,data communication and parallelization of the LBM code using the message passing interface(MPI)library have been investigated.The computational results show that the parallel LBM code exhibits a good high performance computing(HPC)on the parallel speed-up.