Structure,Assembly and Function of Cuticle from Mechanical Perspective with Special Focus on Perianth

This review is devoted to the structure, assembly and function of cuticle. The topics are discussed from the mechanical perspective and whenever the data are available a special attention is paid to the cuticle of perianth organs, i.e., sepals, petals or tepals. The cuticle covering these organs is special in both its structure and function and some of these peculiarities are related to the cuticle mechanics. In particular, strengthening of the perianth surface is often provided by a folded cuticle that functionally resembles profiled plates, while on the surface of the petal epidermis of some plants, the cuticle is the only integral continuous layer. The perianth cuticle is distinguished also by those aspects of its mechanics and development that need further studies. In particular, more investigations are needed to explain the formation and maintenance of cuticle folding, which is typical for the perianth epidermis, and also to elucidate the mechanical properties and behavior of the perianth cuticle in situ. Gaps in our knowledge are partly due to technical problems caused by very small thicknesses of the perianth cuticle but modern tools may help to overcome these obstacles.     

用于远程激光测距机的板条激光器

研制了用于远程激光脉冲测距机的板条激光器。使用半导体泵浦的MOPA激光结构实现了大于250 mJ的脉冲激光输出,输出脉冲宽度为12.83 ns,最终输出激光光束束散角为0.18 mrad。该激光测照器可应用于远程激光测距。对激光测距机的测距与照射能力进行了理论计算与分析。理论分析表明,应用于机载平台时,该激光测照器能够实现50 km距离的激光测距。该型激光测距机具有测距距离远,重量轻,结构紧凑等特点,具有广泛的应用前景。     

Fold and flexibility: what can proteins' mechanical properties tell us about their folding nucleus?

The determination of a protein''s folding nucleus, i.e. a set of native contacts playing an important role during its folding process, remains an elusive yet essential problem in biochemistry. In this work, we investigate the mechanical properties of 70 protein structures belonging to 14 protein families presenting various folds using coarse-grain Brownian dynamics simulations. The resulting rigidity profiles combined with multiple sequence alignments show that a limited set of rigid residues, which we call the consensus nucleus, occupy conserved positions along the protein sequence. These residues'' side chains form a tight interaction network within the protein''s core, thus making our consensus nuclei potential folding nuclei. A review of experimental and theoretical literature shows that most (above 80%) of these residues were indeed identified as folding nucleus member in earlier studies.     

寒冷地区高温干燥条件下混凝土面板裂缝控制

希尼尔水库位于新疆巴音郭楞蒙古族自治州境内，气候特点为高温、干燥、冬季寒冷。根据混凝土面板产生裂缝的原因，并结合工程区的气候特点，认为控制面板的塑性收缩、干缩与冷缩裂缝是防止裂缝产生的重点。通过采用高性能混凝土，合理的养护措施(微喷灌洒水技术)，有效地防止了裂缝的产生，保证了工程质量。     

射频板条CO_2激光器并联谐振技术的研究

本文利用周期性网络模型计算了射频板条CO2激光器电极的纵向电压分布．探讨了并联谐振技术在板条器件中获得成功运用的原因．提出了利用并联谐振技术进一步提高电压分布均匀性的两个途径．     

Insertional re-activation of a chloramphenicol acetyltransferase misfolding mutant protein

The deletion of nine residues from the C-terminus of the bacterialchloramphenicol acetyltransferase (CAT) results in depositionof the mutant protein in cytoplasmic inclusion bodies and lossof chloramphenicol resistance in Escherichia coli. This foldingdefect is relieved by C-terminal fusion of the polypeptide withas few as two residues. Based on these observations, efficientpositive selection for the cloning of DNA fragments has beendemonstrated. The cloning vector encodes a C-terminally truncatedCAT protein. Restriction sites in front of the stop codon allowthe insertion of target DNA, resulting in the production ofproperly folded CAT fusion proteins and regained chloramphenicolresistance. The positive selection of recombinants is accomplishedby growth of transformants on chloramphenicol-containing agarplates. The method appears particularly convenient for the cloningof DNA fragments amplified by the PCR because minimal informationto restore CAT folding can be included in the primers. The cloningof random sequences shows that the folding defect can be relievedby fusion to a wide variety of peptides, providing great flexibilityto the positive selection system. This vector may also contributeto the determination of the role of the C-terminus in CAT folding.     

峡口水库沥青混凝土面板的施工与试验

以灌溉、防洪为主的峡口水库大坝，为沥青混凝土面板堆石坝，为研究低温抗裂性能，对沥青混凝土面板破损取样，进行了配比和多种力学性能试验，并与原面板设计指标进行了对比。由于面板经受住了－20℃以下的低温考验，其所用沥青指标、破损取样试验结果，特别是冻断低温指标，对确定水工沥青混凝土低温抗裂检验标准有重要参考价值。     

钢纤维喷射混凝土作为面板材料的可行性研究

钢纤维混凝土作为一种新型增强材料，以其较好的受力变形特性在水利水电，交通，海岸防护，港口及军事等诸多工程中得到了广泛的应用。针对混凝土面板堆石坝面板的受力变形特点，为改善水布垭面板堆石坝面板的受力条件，提高其防渗能力，同时方便施工，现提出采用钢纤维喷射混凝土作为水布垭面板堆石坝面板材料的新构想，并通过对钢纤维喷射混凝土的物理力学特性及堆石坝面板受力变形进行分析，为钢纤维喷射混凝土在水布垭面板堆石坝面板中的实际应用提出了建议方案。     

薄板坯连铸连轧流程Ti微合金化高强钢开发与应用

在薄板坯连铸连轧流程上，经过对Ti微合金化技术研究，有效解决了Ti微合金化强度性能波动大的问题，开发出屈服强度450～700MPa高强钢。对试制钢组织性能和工业应用分析研究，表明该产品通板性能良好，通板强度差30MPa左右；成形性能良好，d=0时冷弯测试全部合格；同时还具有良好焊接性能，焊接后，强度波动较小，均在母材部位断开；试制钢显微组织为珠光体和铁素体，晶粒均匀细小，平均尺寸为4～8／μm；实物质量满足集装箱和汽车制造行业要求，具有广阔市场前景。     

Corner flow in free liquid films

A lubrication-flow model for a free film in a corner is presented. The model, written in the hyperbolic coordinate system ξ = x ² −y ², η = 2xy, applies to films that are thin in the η-direction. The lubrication approximation yields two coupled evolution equations for the film thickness and the velocity field which, to lowest order, describes plug flow in the hyperbolic coordinates. A free film in a corner evolving under surface tension and gravity is investigated. The rate of thinning of a free film is compared to that of a film evolving over a solid substrate. Viscous shear and normal stresses are both captured in the model and are computed for the entire flow domain. It is shown that normal stress dominates over shear stress in the far field, while shear stress dominates close to the corner. This revised version was published online in October 2005 with corrected page numbers.