看得见、感受得到的高校建筑文化 ——《"新北"生活:北航社区设计成长记》编辑体会

在新中国诞辰72周年前夕,《"新北"生活:北航社区设计成长记》(北京市建筑设计研究院有限公司叶依谦工作室编,天津大学出版社 2021 年 7 月第一版)问世.这虽是本看上去装帧适度的设计作品技术书,但由于他准确、客观地将北航北区学生生活区予以重构的历程深入展示;由于编者与建筑师、学校管理团队积极发掘其中的"故事"且还原设计语境及叙事;由于采用尽可能生动的图文并茂的文风与编辑方式,从而"新北"生活,以约定俗成的文化惯例走进读者(建筑界、教育界乃至社会公众),让高校建筑文化活生生的被人感知.恰如北京航空航天大学副校长刘树春在书序中感慨:"整合资源、优化配套,打造一流的书院式社区正式写入了学校'十三五'规划,打造全新的北区学生社区——'新北',将镌刻北航历史的艺术品升华为能够体现新时代北航精神的艺术品."     

Separation of hematite from banded hematite jasper (BHJ) by magnetic coating

The separation of iron oxide from banded hematite jasper(BHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. Beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade BHJ iron ore under appropriate conditions.     

Strain rate dependency and fragmentation pattern of expanding warheads

For the characterization of the behaviors of a metal material in events like expanding warheads, it is necessary to know its strength and ductility at high strain rates, around 104e105/s. The flyer plate impact testing produces the uniform stress and strain rates but the testing is expensive. The Taylor test is relatively inexpensive but produces non-uniform stress and strain fields, and the results are not so easily inferred for material modeling. In the split-Hopkinson bar(SHB), which may be used in compression, tension and torsion testing, the strain rates never exceeds 103/s. In the present work, we use the expanding ring test where the strain rate is 104e105/s. A streak camera is used to examine the expanding ring velocity, and a water tank is used to collect the fragments. The experimental results are compared with the numerical simulations using the hydrocodes AUTODYN, IMPETUS Afea and a regularized smooth particle(RSPH) software. The number of fragments increases with the increase in the expansion velocity of the rings. The number of fragments is similar to the experimental results. The RSPH software shows much the same results as the AUTODYN where the Lagrangian solver is used for the ring. The IMPETUS Afea solver shows a somewhat different fragmentation characteristic due to the node splitting algorithm that induces pronounced tensile splitting.     

永恒的纪念碑:抗战中的中国建筑师

正2020年是中国全面抗战的"七七"事变83周年,也是世界反法西斯战争胜利75周年。由此,我想到14载为国浴血奋战的抗日将士们,尤其想到面对侵略者中国建筑知识分子也是抗战文化的"播种者",他们让我们在文博与建筑记忆中感悟战争与和平。无论是战争遗址、纪念建筑乃至意象强烈的"墓碑",仿佛都在诉说:历史到底是什么?如果说,抗日战争是对民族精神的一     

Formation of Arrayed Droplets by Soft Lithography and Two-Phase Fluid Flow, and Application in Protein Crystallization

This paper presents an overview of our recent work on the use of soft lithography and two-phase fluid flow to form arrays of droplets. The crucial issues in the formation of stable arrays of droplets and alternating droplets of two sets of aqueous solutions include the geometry of the microchannels, the capillary number, and the water fraction of the system. Glass capillaries could be coupled to the PDMS microchannels and droplets could be transferred into glass capillaries for long-term storage. The arrays of droplets have been applied to screen the conditions for protein crystallization with microbatch and vapor diffusion techniques.     

High Temperature Property Development of Bauxite Based Bricks

Physical properties and microstructural evolution on firing of 3 types of bauxite based refractory bricks were carried out using techniques such as porosimetry,XRD and SEM.The groups differed from each other by progressive refining of the matrix or bond phase.It is revealed that such a refinement of the matrix can improve the high temperature properties of the bricks made from poor grade materials.     

Charge： Glowing in the Dark

Many areas of structure analysis have focused on finding the locations of the atoms. If, instead of the atoms, we knew the positions of the electrons we would in fact know much more, and in most respects knowing where the nuclei are is not important. There is a long history of measurements using precise electron diffraction or X-ray diffraction of the average charge density in materials, but extending beyond to local charge density is, as yet, an unexplored area.     

DIRECT RESONANCE OF TURBULENT BOUNDARY LAVER OVER COMPLIANT WALLS

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