冬季无加湿功能全空气系统室内状态参数的确定及混风段凝水现象分析

针对暖通空调工程全空气系统中常用的无加湿段组合空调箱的特点,对如何确定冬季送风参数的问题提出了2种方法:理论计算方法和绘图法,并推荐绘图法。同时对工程中遇到的严寒地区应用全空气系统供暖时新回风混合段的凝水现象进行原因分析,并提出解决办法。

对人性与历史的追问与审视——评李锐小说《旧址》

“德国哲学家海德格尔认为……任何存在都是在一定时间空间条件下的存在,即定在、超越自己历史环境的存在是不可能的,存在的历史性决定了理解的历史性……阐释是以我们已经先有、先见、先把握的东西为基础.这种意识的“先结构”“使理解和解释总带着解释者自己的历史环境所决定的成份”、(张隆溪《仁者仁者,智者智见》)我以为,对历史的解读也是如此.或许是十年浩劫对人性摧残的惨烈给作者留下了刻骨铭心的记忆与不能释怀的追根问底的深思,或许是风云变迁人生变幻使作者感受到了历史的沧桑与悲凉,总之,读《旧址》、让我体味到了面对历史旧址的一个特定时代的一代人的情怀.这种情怀,不同于兴奋于“旧貌变新颜”的喜悦,壮烈,自豪;不同于无奈“不知从何处来,向何处去”的寂寞,悲哀,痛苦;也不同于将意义,价值暂时“束之高阁”“置于括弧之中”的轻松中的无奈.这是人文理想火炬的燃烧,是不愿放弃真挚追寻的努力,是对人性与历史历程的痛思与反省,是人类精神价值追寻中的一段凝重流程.它的核心,是对人性何以会被扭曲,窒息,戕害的追问,是对历史与人性关系的再次审视.

趣味生活片段全记录

＂不积细流,无以成江海＂,生活永远是写作的源泉。在生活中感受,在生活中体验,在生活中积累,在生活中思考,就会有无穷无尽的鲜活的写作灵感和素材。我们尝试着引领中年级学生聚焦生活实际,进行多样化的生活小片段练习。经过实践我们发现,这样的小型练习,让学生的文字平添了不少纯真和童趣。

Discovery and identification of clay-sized tuffaceous rocks in Chang 7 Member of Upper Triassic Yanchang Formation in Ordos Basin,China

This study for the first time demonstrates that some of the so-called clay-sized mudstones observed by the naked eye,such as clay-sized black mudstones and clay-sized oil shales,which are rich in black organic matter(including oil and asphaltene),in the Chang 73 Submember of the Upper Triassic Yanchang Formation in the Ordos Basin of China are actually clay-sized tuffaceous rocks(including tuff,sedimentary tuff and tuffaceous sedimentary rock)with high hydrocarbon generation capacities.Thus,these rocks can be defined as clay-sized tuffaceous source rocks.Identification of this lithology has important theoretical and practical significance for the exploration and development of shale oil in the Chang 7 Member.Through the macroscopic observation of drill cores and outcrop profiles,microscopic observation of electron probe thin sections and whole-rock inorganic geochemical analysis(including major,trace and rare earth elements),this work demonstrates that the organic matter-rich clay-sized tuffaceous rocks,especially clay-sized tuffs,have the following characteristics.First,the clay-sized tuffaceous rocks with little black organic matter are mainly greyish white,yellowish brown and purplish grey,and mixed colors occur in areas with strong bentonite lithification.Second,the clay-sized tuffaceous rocks have experienced strong devitrification and recrystallization,forming abundant flaky aluminosilicate minerals with directional arrangement.In thin sections under a polarizing microscope,the interference colors generally show regular alternation between the lowest interference color of first-order yellow and the highest interference color of second-order blue-green.Third,the rock samples plot in the igneous rock field in the TiO2-SiO2 cross-plot and exhibit similar trace element and rare earth element patterns on spider diagrams,indicating that the samples are derived from the same source.The results prove that clay-sized tuffaceous rocks may be widespread in the Chang 73 Submember of the Upper Triassic Yanchang Formation in the Ordos Basin,China.

Numerical Staged Construction Analysis of Precast Concrete Bridge

The paper discussed about the staged construction analysis of two-span precast-girder bridge considering time dependent effects, namely creep and aging of concrete. Results obtained showed that it is very important to consider construction stage in the analysis of bridge because of stress resultants which are important in design process and very different from those obtained without the consideration of construction stage. This fact is especially important for bridges, because construction period continues along time and loads may change during the construction period and after.

Cyclic test and numerical study of seismic performance of precast segmental concrete double-columns

The comparative research on the seismic performance of grouted sleeve connected pier(GS)and prestressed precast segmental concrete pier(PC)is mostly carried out by numerical simulation.In this study,the GS pier and the PC pier of the new railway project from Hetian to Ruoqiang are taken into consideration.Two kinds of 1/5-scale assembled double-column specimens are made,and the quasi-static tests are carried out.The overall seismic performance of the two spliced piers is studied,and compared in terms of failure mechanism,bearing capacity,ductility,stiffness and energy dissipation capacity.The results show that the failure modes of both GS pier and PC pier are characterized by bending.However,the specific failure location and form are different.The GS pier presents a complete hysteretic curve,large equivalent stiffness and strong energy dissipation capacity.The hysteretic area of the PC pier is small.However,it has good self-reset ability and quasi-static residual displacement.Finite element models are set up using DispBeamColumn fiber elements and ZeroLength elements.The models that are calibrated with the test data can effectively simulate the damage development under monotonic loading.The load−displacement curves are in good agreement with the backbone curves of the test results.

Probiotic metabolites from Bacillus coagulans GanedenBC30^(TM) support maturation of antigen-presenting cells in vitro

AIM:To study the effects of probiotic metabolites on maturation stage of antigen-presenting immune cells.METHODS:Ganeden Bacillus coagulans 30(GBC30) bacterial cultures in log phase were used to isolate the secreted metabolite(MET) fraction.A second fraction was made to generate a crude cell-wall-enriched fraction,by centrifugation and lysis,followed by washing.A preparation of MET was subjected to size exclusion centrifugation,generating three fractions:< 3 kDa,3-30 kDa,and 30-200 kDa and activities were tested in comparison to crude MET and cell wall in primary cultures of human peripheral blood mononuclear cell(PBMC) as a source of antigen-presenting mononuclear phagocytes.The maturation status of mononuclear phagocytes was evaluated by staining with monoclonal antibodies towards CD14,CD16,CD80 and CD86 and analyzed by flow cytometry.RESULTS:Treatment of PBMC with MET supported maturation of mononuclear phagocytes toward both macrophage and dendritic cell phenotypes.The biological activity unique to the metabolites included a reduction of CD14+ CD16+ pro-inflammatory cells,and this property was associated with the high molecular weight metabolite fraction.Changes were also seen for the dendritic cell maturation markers CD80 and CD86.On CD14dim cells,an increase in both CD80 and CD86 expression was seen,in contrast to a selective increase in CD86 expression on CD14bright cells.The co-expression of CD80 and CD86 indicates effective antigen presentation to T cells and support of T helper cell differentiation.The selective expression of CD86 in the absence of CD80 points to a role in generating T regulatory cells.CONCLUSION:The data show that a primary mechanism of action of GBC30 metabolites involves support of more mature phenotypes of antigen-presenting cells,important for immunological decision-making.

Bridge Falsework in Staged Construction of a Prestressed Concrete Beam Bridge

The formwork and falsework in the construction of twin ribbed slab decks on a multi-span ecological bridge for a dual carriageway are presented. The bridge is situated in a valley plain which is crossed by small rivers and was designed principally with the environment in mind. The bridge length is over 356 m, and the width of the decks is 11.5 m. For the bridge works, a simple conventional falsework system was chosen with steel frames for the supports and steel rolled beams for the decks. The formwork was constructed in solid timber and plywood as multiple-use panels. The falsework was designed in order to build the two 10-span bridge decks in stages. The decks are continuous cast-in-situ prestressed concrete twin rib with spans of 30 m, 34 m and 45 m. An individual falsework system was designed, which was easy to move transversally following completion of each stage for one deck. After finishing each stage, for the second deck, the falsework was dismantled and used again in the next construction fronts. An individual arrangement for the falsework along with timber pilings was used to cross the biggest river. The formwork timber panels were used several times in the multistage bridge construction. The adopted falsework system is very simple, but it allowed the speedy construction of the two decks where there were severe time constraints.

尚和玉——一代武生典范

台上一阵紧锣密鼓,旋即大饶响起,在“四击头”声中,一员武将红三块瓦睑谱上勾一硕大的太极图,身扎绿靠,戴黑满髯,腰悬宝剑,威武凝重地步上舞台。这员武将便是京剧武生巨匠尚和玉饰演的三国蜀将姜维。但见尚和玉在刚一上场的“起霸观星”中,工架气势,卓尔不群,一举手,一投足,无不准绳合度,处处交代清楚,身段凝实而稳重,硬砍实凿,不尚花巧。台上虽只一人,然气势磅礴,直如干军万马,面迎大敌。紧接几场开打,无论对手如何迅急。

旋转的岁月

没有高档豪华的家具,没有气派非凡的装饰,更无价值连城的宝器,我的家就是这样的朴素而简单。记得14年前,随着父母的工作调动,我走进了黄龙县城。

Experimental Study on the Condensation of a Thermosyphon by Electrical Capacitance Tomography

The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT) sensor was designed for the visualization measurement in a liquid by removing the shielding case and sealing with insulating hydrophobic material. It was successfully used to measure the condensation process in a thermosyphon under different operating temperatures. The thermosyphon was made of silica glass, and alcohol was used as a working fluid. The alcohol vapor was cooled to condense through the heat convection with the cooling water. The operating temperature was controlled by a heater with different power outputs. The experimental results show that the alcohol vapor condensed in stripes and unevenly on the wall surface at a low operating temperature. The liquid bridge will be formed periodically at the operating temperature of 90?C, and the time interval between two liquid bridges will be shorter with the increase of the operating temperature. At 117?C or even higher operating temperatures, the complete liquid bridge cannot be formed sometimes due to the difference of the growth rate of the surface wave around the circumference.

Designing the mechanical properties of peptide-based supramolecular hydrogels for biomedical applications

Hydrogels are a class of special materials that contain a large amount of water and behave like rubber.These materials have found broad applications in tissue engineering,cell culturing,regenerative medicine etc.Recently,the exploration of peptide-based supramolecular hydrogels has greatly expanded the repertoire of hydrogels suitable for biomedical applications.However,the mechanical properties of peptide-based hydrogels are intrinsically weak.Therefore,it is crucial to develop methods that can improve the mechanical stability of such peptide-based hydrogels.In this review,we explore the factors that determine or influence the mechanical stability of peptide-based hydrogels and summarize several key elements that may guide scientists to achieve mechanically improved hydrogels.In addition,we exemplified several methods that have been successfully developed to prepare hydrogels with enhanced mechanical stability.These mechanically strong peptide-based hydrogels may find broad applications as novel biomaterials.It is still challenging to engineer hydrogels in order to mimic the mechanical properties of biological tissues.More hydrogel materials with optimal mechanical properties suitable for various types of biological applications will be available in the near future.

Tunable supramolecular hydrogels from polypeptidePEG-polypeptide triblock copolymers

A series of ABA triblock copolymers of poly(?-(2-methoxy ethoxy)esteryl-glutamate)-block-poly(ethylene glycol)-blockpoly(?-(2-methoxy ethoxy)esteryl-glutamate) with poly(ethylene glycol) as middle hydrophilic B block and oligo(ethylene glycol)-functionalized polyglutamate(poly-L-EG2Glu) as terminal A blocks were prepared via ring-opening polymerization of EG2 Glu N-carboxyanhydride(NCA). The resulting P(EG2Glu)-b-PEG-b-P(EG2Glu) triblocks can spontaneously form hydrogels in water. The intermolecular hydrogen bonding interactions between polypeptides blocks were responsible for the formation of gel network structure. These hydrogels displayed shear-thinning and rapid recovery properties, which endowed them potential application as injectable drug delivery system. The mechanical strength of hydrogels can be modulated by copolymer composition, molecular weight and concentrations. Also, it was found that the hydrogels' strength decreased with temperature due to dehydration of polypeptide segments. Atomic force microscopy and scanning electron microscopy images revealed that these hydrogels were formed through micelle packing mechanism. Circular dichroism and Fourier transform infrared spectroscopy characterizations suggested the poly-L-EG2 Glu block adopted mixed conformation. A preliminary assessment of drug release in vitro demonstrated the hydrogels can offer a sustained release of doxorubicin(DOX) and the release rate could be controlled by varying chemical composition.