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Degeneracy and discreteness in cosmological model fitting

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Research in Astronomy and Astrophysics 2016年第3期16卷 121-128页

作者： Huan-yu teng yuan Huang Tong-Jie Zhang Department of Astronomy Beijing Normal UniversityBeijing 100875China Departments of Physics and Astronomy University of CaliforniaBerkeleyCA 94720USA Lawrence Berkeley National Laboratory 1 Cyclotron RoadBerkeleyCA 94720USA

We explore the problems of degeneracy and discreteness in the standard cosmological model（ΛCDM）. We use the Observational Hubble Data（OHD） and the type Ia supernovae（SNe Ia） data to study this issue. In order to describe the discreteness in fitting of data, we define a factor G to test the influence from each single data point and analyze the goodness of G. Our results indicate that a higher absolute value of G shows a better capability of distinguishing models, which means the parameters are restricted into smaller confidence intervals with a larger figure of merit evaluation. Consequently, we claim that the factor G is an effective way of model differentiation when using different models to fit the observational data.

关键词： cosmological parameters -- cosmology: observations -- methods: statistical

Characteristics of long period microtremor and validation of microtremor array measurements in inland areas of China

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Journal of Mountain Science 2016年第11期13卷 1910-1922页

作者： CHE Ai-lan ZHANG teng-yu FENG Shao-kong School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University 800 Dongchuan-Road Shanghai 200240 China

To study the characteristics of long period microtremor and applicability of microtremor survey,we have made microtremor observations using long period seismometers of the China's mainland from coastal cities like Shanghai and Tianjin through Beijing,Xi'an,to the far inland cities of Lanzhou and *** observation shows that the level of power spectrum of long period microtremors reduced rapidly from the coast to the inland ***,the energy of long period microtremors in Beijing,Xi'an,Lanzhou and Tianshui area are only approximately ten-thousandth to thousandth of that in *** at the complexity of the underground structure in the far inland,a series of underground structure models with different distributions were assessed using three-dimensional,dynamic finite element method(FEM) *** results were used to evaluate microtremor survey methods and their limitations with regard to aggregate variability and thickness ***-wave reflections between layers with the change of underground structure distribution occurred,which have significant effect on the performance of the different field *** over a broad spectrum from which velocity-depth profiles were produced via inversion *** the thickness nor the shear waveVelocity V of the subsurface layer inversion results appeared over a large evaluation with increasing slope *** particular,when the angle of the model reached 45°,it could not be accurately evaluated using one-dimensional inversion ***,the array microtremor survey(AMS) was carried out in Shanghai City,*** AMS techniques do not have the layer sensitivity or accuracy(velocity and layer thickness) of borehole techniques,the obtained shear wave velocity structure is especially useful for earthquake disaster prevention and seismic analysis.

关键词： Long period microtremor Array Microtremor survey Power spectrum Inversion S-wave velocity structure

Interaction between γ'precipitate distribution and microstructure homogeneity during hot deformation in a Ni-based superalloy

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Journal of Iron and Steel Research International 2023年第11期30卷 2301-2317页

作者： Cheng-yu Wang teng An yu Gu Zhong-nan Bi Jin-hui Du Jing-long Qu Beijing Key Laboratory of Advanced High Temperature Materials Central Iron&Steel Research InstituteBeijing100081China Beijing GAONA Materials&Technology Co. Ltd.Beijing100081China

The inhomogeneous microstructure of the Ni-based superalloys used for turbine disks was an intolerable defect for the mechanical *** effects of the distribution ofγ'precipitate,forging temperature,and strain level on the microstructure evolution of GH4730 alloy were investigated by EBSD during hot *** results showed that the heterogeneous factor peaked at the transition temperature from the single-phase to the double-phase *** coupling effect of heat and stress led to the heterogeneous precipitation and distribution ofγ'phase during the transition region,which was the main reason for the formation of inhomogeneous *** coherentγ'phases of approximately 0.3μm were diffusely distributed inside the large grains,increasing the grain strength,making recrystallization refinement difficult,and thus forming large unrecrystallized *** incoherentγ'phases with a size of approximately 1.1μm located at the grain boundaries and pinned the grain boundaries,and thus the accumulated strain at the grain boundaries caused the occurrence of discontinuous dynamic recrystallization and promoted continuous refinement of the *** microstructure evolution of new Ni-based superalloys during hot forging was focused,and the formation mechanism of inhomogeneous microstructure and control measures was explained.A theoretical basis for improving the microstructure homogeneity of the new cast and wrought superalloys was provided.

关键词： GH4730 alloy Hot deformation γ′phase Heterogeneous factor Microstructure homogeneity

Construction and manipulation of origami-inspired tubular structures with controlled mechanical buckling for collection and transportation of microspheres based on optically induced electrokinetics

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Science China(Technological Sciences) 2024年第9期67卷 2954-2964页

作者： YANG WenGuang WANG WenHao teng Xiangyu QIAO ZeZheng yu HaiBo School of Electromechanical and Automotive Engineering Yantai UniversityYantai 264005China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016China

The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlled mechanical buckling based on optically induced electrokinetics(OEK). By inducing a stress gradient in the thickness, a tubular structure can be formed from a poly(ethylene glycol) diacrylate(PEGDA) hydrogel film of various shapes that have been custom fabricated. To achieve an ideal three-dimensional(3D) structure, the amplitude of the tubular structure can be controlled by adjusting the aspect ratios or polymerization time. Furthermore, the tubular structure can be manipulated for the collection and transportation of *** summary, we provide an effective method for designing 3D structures at the micro-nano scale. This forming method holds great potential for achieving various functions in tissue engineering, drug packaging, and transportation in the future.

关键词： origami-inspired tubular structures optically induced electrokinetics microfabrication mechanical buckling

Research on a MEMS pyrotechnic with a double-layer barrier safety and arming device

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Defence Technology（防务技术） 2022年第11期18卷 2034-2044页

作者： Ke-xin Wang teng-jiang Hu yu-long Zhao Wei Ren State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong UniversityXi'an710049China Science and Technology on Applied Physical Chemistry Laboratory Shaanxi Applied Physical Chemistry Research InstituteXi'an710061China

As an essential component of ammunition, pyrotechnics can control ignition with high ***, due to limits of fabrication technology, traditional pyrotechnics are bulky. To achieve both functionality and miniaturization, MEMS pyrotechnics integrate initiator, safety-and-arming(S&A) device and lead charge and keep all components within a small size. MEMS S&A devices, as the core component to ensure system safety, are difficult to achieve active and rapid response to control signals with high safety and reliability. In order to overcome the difficulty, we propose the design and characterization of a MEMS pyrotechnic with a double-layer barrier S&A device. The MEMS pyrotechnic is a high-integrated device with an overall size of 13.4 × 8.5 × 5.2 mm^(3). The initiator is a Ni Cr bridge foil covered with an Al/Cu O energetic film, which can generate flame when ignited by an excitation *** match the flame energy, lead styphnate is chosen in this study as the lead charge. The S&A device contains four semi-circular barriers, which are directly driven by V-shape electro-thermal actuators to gain active control of the pyrotechnics’ ignition condition with rapid response. To improve the system’s reliability, the four barriers are axisymmetrically placed in two layers, two barriers for each layer, to constitute a double-layer structure with a thickness of 100 μm. The ignition test results show that the S&A device can prevent the initiator from detonating the lead charge in safety condition. In arming condition, the lead charge will be detonated.

关键词： MEMS Pyrotechnics Safety and arming device Initiator Electro-thermal actuator

Controlled synthesis and closed-loop chemical recycling of biodegradable copolymers with composition-dependent properties

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Science China Chemistry 2022年第5期65卷 943-953页

作者： Yi-teng Yan Gang Wu Si-Chong Chen yu-Zhong Wang The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE) National Engineering Laboratory ofEco-Friendly Polymeric Materials(Sichuan)State Key Laboratory of Polymer Materials EngineeringCollege of ChemistrySichuan UniversityChengdu 610064China

The closed-loop recycling concept of the polymer wastes into building-block chemicals is attractive,but the closed-loop recycling of copolymers enabled by energy-efficient chemical recycling and cost-effective separations is still facing great ***,for the first time,a one-pot sequential copolymerization of γ-butyrolactone(γ-BL) and p-dioxanone(PDO)using an economical ureas/alkoxides catalytic system is conducted to synthesize biodegradable and chemically recyclable poly-(γ-butyrolactone)-block-poly(p-dioxanone)(PγBL-b-PPDO) diblock copolymers with well-defined and controlled *** composition-dependent properties of PγBL-b-PPDO copolymers,including thermal properties and crystallization behavior,are *** results show that the thermal stability and crystalline ability of PγBL are enhanced observably by introducing the PPDO ***,the PγBL-b-PPDO copolymers can be depolymerized efficiently into the corresponding co-monomers with a yield of over 95% by simply low-temperature pyrolysis under ***,γ-BL and PDO monomers are selectively separated with an isolated purity of about 99% based on the difference in their physicochemical ***,their repolymerization is realized to obtain the copolymers with nearly identical structures and thermostability,demonstrating the closed-loop recycling of copolymers,i.e.,*** research provides important guidance for the design of novel sustainable polymers towards more efficient chemical recycling,separation and regeneration.

关键词： biodegradable copolyester poly(p-dioxanone) tunable properties closed-loop chemical recycling

Novel PLGA Microspheres for Sustained Delivery of Antisense Oligonucleotide

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Chemical Research in Chinese Universities 2013年第5期29卷 1003-1005页

作者： XIE Jing LI Xin JIANG Chao-jun lee Robert Jian-guang ZHOU yu-lin teng Le-sheng College of Life Science Jilin University Changchun 130012 P. R. China College of Pharmacy Ohio State University Columbus 43210 USA The Second Hospital of Jilin University Changchun 130041 P. R. China

Novel poly（lactide-co-glycolide acid）（PLGA） microspheres were developed for sustained delivery of antisense oligonucleotide（ASO）. First, a new cationic agent, polyethylenimine（PEI） conjugated to linoleic acid（LA）（PEI-LA） was synthesized by reacting PEI（Mw=800） with linoleoyl chloride. Then, PEI-LA was combined with LOR-2501 to form electrostatic complexes at moderate nitrogen-to-phosphate（N/P） molar ratios which were then encapsulated into poly（lactide-co-glycolide） microspheres by a multiple emulsion-solvent evaporation technique. With an increase in ASO/PEI-LA concentration from 5% to 10%, encapsulation efficiency of ASO in the micro- spheres reduced from 72.14% to 57.62%, and the particle size ofmicrospheres increased from 28.58 μm to 34.76 μm. In vitro studies show that the release profile of ASO from microspheres prepared at 7.5% ASO-PEI-LA lasted for 14 d The novel microspheres have a potential use as a sustained release vehicle for ASO.

关键词： Drug delivery PLGA microsphere Polyethylenimine Antisense oligonucleotide

A new drug carrier:Magnetite nanoparticles coated with amphiphilic block copolymer

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Chinese Science Bulletin 2009年第7期54卷 1190-1196页

作者： CHANG yu BAI yunPeng teng Bao LiZhaoLong Department of Chemistry Tsinghua University Beijing 100084 China

This paper reports on the synthesis and characterization of 4 nm magnetite nanoparticles coated with amphiphilic block copolymers of poly(ethyl methacrylate)-b-poly(2-hydroxyethyl methacrylate) (PEMA- b-PHEMA) by surface-initiated atom transfer radical polymerization (ATRP), which can act as new potential carriers for hydrophobic targeted drug delivery. Vibrating sample magnetometer analysis indi-cated that the magnetite nanoparticles were superparamagnetic at room temperature. Thermogravim-etric analysis (TGA) was applied to studying the property of surface of magnetite nanoparticles, and the surface density of macromolecules was calculated. The grafting density of oleic acid, BrMPA and PEMA was 5.8, 3.9, 0.16 chain/nm2 respectively, which indicates that the initiation efficiency decreases due to the influence of large space of oleic acid molecules. In vitro progesterone and (-)-isoproterenol hy-drochloride release in phosphate buffered saline (PBS) at pH 7.0 and 37℃ was conducted in order to demonstrate the function of drug loading and release. The results showed that the amount of drug carried into the core-shell Fe3O4@PEMA-b-PHEMA depends on the length of hydrophobic segment of block copolymer. The release of progesterone (37% after 22 h in our previous work) was compared with the release of (-)-isoproterenol hydrochloride (80% after 50 min), demonstrating that the strong hy-drophobic interaction between hydrophobic segment and drug can effectively control the release of hydrophobic drugs.

关键词：双亲嵌段共聚物纳米涂层药物载体磁铁矿原子转移自由基聚合甲基丙烯酸乙酯盐酸异丙肾上腺素磁性纳米粒子

Magnetic property and recording performance of chemical deposition CoP thin films

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Rare Metals 2012年第3期31卷 260-263页

作者： Wang, Haicheng Zhou, Qunfei teng, Jiao Wang, Lijin yu, Guanghua Department of Material Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China

The thickness of CoP thin films prepared by wet chemical deposition is of crucial importance on magnetic property and recording perform-ance. The coercivity of CoP films decreased with increasing film thickness. The coercivity was 45.37 kA m 1 at the thickness of 300 nm, and decreased to 21.65 kA m 1 at 5.7 μm. Recording performance tests indicate that, for drums with the same size, different recorded magnetic pole density have different thickness requirements. For 40 mm diameter magnetic drum, the optimal CoP thickness is 3～10 μm for 256 re-corded magnetic poles, 1～2 μm for 512 recorded magnetic poles, and 500～800 nm for 1024 recorded magnetic poles.

关键词： CoP thin films magnetic property magnetic recording