Leaf Micro-Morphology in Two Ecotypes of Ashleaf Maple Adaptated to Different Survival Environments

Through one hundred years of adaptation in China, The Acer negundo Linn. (as hlea f maple), originally grown in North America, has developed morphological charact er istics to cope the severe situation of its habitats. Two ecotypes from different vegetation belts in the ecotone of eastern Inner Mongolia Autonomous Region wer e detected. Although there was no macroscopic difference, contrasting micro-ch a racteristics had been observed between the two sources. The leaves from more dro ught and warmer zone were found with more trichomes, more and smaller stomata, l arger subsidiary cells, thicker palisade and flatter epidermal wax than those of leaves from the more humid and colder zone. Microstructures of the leaves from xeric sources can more effectively reduce leaf temperature and conserving water than those of mesic sources. Intra-species difference of the two ecotypes is th e result of adaptation in different environments. This should be considered when characteristics of foliage are used as characters of species in taxonomy.

Micro-CT分析跟骨内骨小梁分布及结构特征

背景:跟骨位于足的后下部,受力较大。跟骨外形复杂且不规则,外周有较薄的皮质骨包绕,内部充满大量的骨小梁,探讨骨小梁的微观结构、走行及分布特征有助于提高对跟骨骨折的认识。目的:采用微计算机断层扫描仪(Micro-CT)扫描跟骨标本获得其影像资料,对其内部骨小梁结构进行分析,探讨跟骨内骨小梁的形态、分布及结构特征。方法:采用Micro-CT连续扫描干燥成人跟骨标本,扫描后获得影像图像,将其以DICOM格式存储。导入影像资料到Hiscan Analyzer软件,显示清晰完整的成人跟骨矢状面、冠状面、水平面的图像,逐层观察骨小梁的走行,依据骨小梁走行特点将跟骨矢状面分为6个部分,在以7 mm为标准的相同厚度下,每个部分选择1个49 mm2等面积的兴趣区,三维重建后获得跟骨及骨小梁的立体微观结构,二值化后运用软件计算感兴趣区域内骨小梁的体积分数、表面密度、骨小梁厚度、骨小梁间隙和骨小梁数量参数。结果与结论:①跟骨表面皮质层很薄,内部充满大量骨松质,在Gissane角的骨皮质明显增厚;②跟骨上部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨结节部、跟骨底部,跟骨结节部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨底部;跟骨结节部的骨小梁表面密度大于跟骨下部前端、中和三角区、跟骨底部,跟骨上部、跟骨下后部的骨小梁表面密度大于中和三角区;跟骨上部的骨小梁厚度大于跟骨结节部;中和三角区的骨小梁间隙大于跟骨上部、跟骨结节部;跟骨结节部的骨小梁数量大于中和三角区;③中和三角区主要分布杆状骨小梁,骨小梁表面密度最小、体积分数较小、骨小梁间隙最大;该部位骨质较疏松,受到高冲击力时抗压缩能力差,骨小梁最先发生断裂,是易发生骨折的部位。

Application of micro/nanoscale thermal radiation to thermophotovoltaic system

Thermophotovoltaic （TPV） system has been regarded as one promising means to alleviate current energy demand because it can directly generate electricity from radiation heat via photons. However, the presently available TPV systems suffer from low conversion efficiency and low throughput. A viable solution to increase their efficiency is to apply micro/nanoscale radiation principles in the design of different components to utilize the characteristics ~f thermal radiation at small distances and in microstructures. Several critical issues are reviewed, such as photovoltaic effect, quantum efficiency and efficiency of TPV system. Emphasis is given to the development of wavelength-selective emitters and filters and the aspects of micro/nanoscale heat transfer. Recent progress, along with the challenges and opportunities for future development of TPV systems are also outlined.

Root canal morphology and configuration of 123 maxillary second molars by means of micro-CT

The aim of this study was to investigate the root canal configuration, accessory canals and number of main foramina of 123 maxillary second molars by means of micro-computed tomography. The teeth were scanned and reproduced with 3D software imaging. The root canal configuration and number of main foramina were evaluated by means of a four-digit system. The morphological complexity of human maxillary second molars is depicted by the number of accessory and connecting canals. The most frequently observed root canal configurations in the mesiobuccal root were 2-2-2/2 （19.5%）, 2-2-1/1 （14.6%） and 2-1-1/1 （13.0%）. A 1-1-1/1 configuration was observed in 93.5% and in 96.7% in the distobuccal and palatal roots, respectively. The MB1 mot canal had one accessory canal （18.7%）, and 8.9% of the MB2 root canal had one or two accessory canals. The distobuccal （11.3%） and palatal （14.6%） root canals had at least one accessory canal, and connecting canals were observed in 16.3% of mesiobuccal roots. The MB1, MB2, distobuccal and palatal root canals had one main foramen in 99.2%, 43.1%, 98.4% and 99.2% of samples, respectively. In the mesiobuccal root, one accessory foramen was detected in 14.6%, two were detected in 7.3%, and three were detected in 5.7%. The distobuccal root showed one or two accessory foramina in 9.1% of samples. The root canal configuration of maxillary second molars is quite heterogeneous; the mesiobuccal root has predominantly two root canal entrances （58.4%, 1 in 41.1%） with one main foramen （54.4%）. Two main foramina were observed in 43.0%. Morphological variations, connecting and accessory canals were observed in all apical thirds.

Effect of substrate micro-morphology on heterogeneous nucleation

The heterogeneous nucleation process of NH4Cl crystals from a NH4Cl-70wt.%H2O solution on rough chilling substrates was considered in this paper. Scratched and etched substrates of aluminum were prepared with different surface morphologies. It was concluded that for nucleation to occur on a rough substrate surface, the wettability or the generally said roughness are not the key factors affecting the heterogeneous nucleation process. Rather the surface morphologies on the nanometer scale, which is close to the scale of the critical nucleation radius, are more important.

The Characteristics of Quartz Micro-morphology of The Fault Gouge in Bailongjiang Fault System and Its Chronology

A great deal of important information referring to fault motion (such as fault activities period, intensity, frequency, and even dynamic background, etc.) can be revealed by resolving fault gouge, which are the special result of fault motion while extruding or grinding. Based on the field investigation, collected from Bailongjiang fault system of Western Qinling Orogenic (QO) Belt, 44 samples of fault gouge were for quartz micro-morphology observation and statistics by the field emission SEM, and 14 samples were tested by thermo-luminescence dating. The results showed that most of the micro-morphology of quartz grains are fish scale and orange-haut fractures, but a small amount of moss-like, stalactitic, and subconchoidal fractures. Also very few decay of quartz grains and typical conchoids fracture quartz grains can be seen. This implied that the Bailongjiang fault system was motioned repeatedly in Quaternary period but main motion period was Pleistocene. 14 thermo-luminescence dating values showed herewith two groups as 343.29-184.06 ka and 92.18-13.87 ka. Therefore, the conclusions can be reached that the fault system were motioned starting at Pliocene epoch, frequently in the middle of Pleistocene (343.29-184.06 ka), and peak frequency in late Pleistocene (92.18-13.87 ka). The fault system motions have stopped at Holocene. The results are significant for the natural disaster risk evaluation in western QO region.

Micro-morphological Features of Topsoil under Long-term Cultivation of Grain and Cotton Crops in Northwestern Shandong

This study aimed to provide a basis for the rational improvement of the microstructure of the soil that had been planted with crops for a long time. Conventional and micro-morphological methods were used to study the effects of planting grain and cotton crops on soil properties in Gaotang County,Shandong Province. The results showed that long-term cultivation of grain and cotton crops has a significant impact on soil micro-structure. The top soil( 0-10 cm) of wheat-maize field has higher organic matter content,uniform aggregate size,high separation,and strong packing void connectivity,forming a type micro-structure that is conducive to agricultural production. The characteristics of soil matrix are mainly inherited from soil parent materials,and the impact of crop cultivation on soil matrix is very weak. The amount of formations in the soil is less,and only Fe nodules,Mn nodules and excrement are observed.

Generating micro/nanostructures on magnesium alloy surface using ultraprecision diamond surface texturing process

The lightness and high strength-to-weight ratio of the magnesium alloy have attracted more interest in various applications.However,micro/nanostructure generation on their surfaces remains a challenge due to the flammability and ignition.Motivated by this,this study proposed a machining process,named the ultraprecision diamond surface texturing process,to machine the micro/nanostructures on magnesium alloy surfaces.Experimental results showed the various microstructures and sawtooth-shaped nanostructures were successfully generated on the AZ31B magnesium alloy surfaces,demonstrating the effectiveness of this proposed machining process.Furthermore,sawtooth-shaped nanostructures had the function of inducing the optical effect and generating different colors on workpiece surfaces.The colorful letter and colorful flower image were clearly viewed on magnesium alloy surfaces.The corresponding cutting force,chip morphology,and tool wear were systematically investigated to understand the machining mechanism of micro/nanostructures on magnesium alloy surfaces.The proposed machining process can further improve the performances of the magnesium alloy and extend its functions to other fields,such as optics.

Loss of Masticatory Function Affects Morphology of the Tooth Root in Rats

Masticatory hypofunction and soft food affect the tooth rows, occlusion, and jawbone. This study aimed to clarify the influence of tooth loss and a soft diet on morphology of the tooth root during the growth period. We divided 3-week-old Wistar rats into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). Length, width, cross-sectional area, and volume of the root of the mandibular M1 and M2 were measured using micro-CT analysis. Non-decalcified thin-slice specimens of sagittal sections of the M1 were obtained at the age of 20 weeks, and the roots were observed. The root length of all roots in the Extraction group was significantly longer than that in the other groups. The root width and cross-sectional area at the apical side 1/4 of all roots in the Extraction group were significantly smaller than those in the other groups. The root volume of the M1 mesial root in the Extraction group was significantly smaller than that in the other groups. This study clarified that when masticatory stimulus in the immature teeth is reduced by the extraction of opposing teeth and a powder diet, the root length increases due to the promotion of cellular cementum addition at the apex, and the root width and cross-sectional area decrease due to the suppression of cellular cementum addition at the apical side 1/4 of the roots.

Biodiversity of the Micro-morphologies of the Petal Epidermis of Angiosperms &Their Scientific Aesthetics, Quasi-Geometry

The micro-morphologies and biodiversities of the epidermis of flower petals of angiosperms were reported for the first time. By manual slicing anatomy and microscopic photography technique, the micro-morphologies of the upper and lower epidermis of petals of some common ornamental flowers in Kunming were studied, and the biodiversities were discovered. The results showed these much-varied pigment cells appeared not only a new compensation to anatomy, but a new criteria to taxonomy, so that a brand new research field of “Cell Taxonomy” was established instead of the current “Chromosome Taxonomy” widely used in phytosystematics research. Furthermore, the most interesting and significant phenomena was their scientific aesthetics: these pigment cells of flower petals were quite special, planary, far different from the ordinary plant cells in plant organs & tissues. By comparison to ordinary geometry, these colorful cells of the fresh flower petals could be described as “Quasi-geometry” for their special origin and micro-morphological characteristics. As for the aspect of art, it was quite similar to “Quasi-crystal” discovered by Daniel Schechtman, so that the art future was discussed, obviously another new epoch of scientific-art history began.

微/纳米级有机空心粒子构造及功能应用研究进展

随着材料科学领域的不断发展,空心粒子因具有比表面积高、密度低、稳定性优异等诸多优势而在功能性材料中崭露头角,进而成为研究热点。本文首先介绍了空心粒子的基本类型,包括无机空心粒子、有机空心粒子,其中有机空心粒子因具有结构稳定、可修饰性强、易于调控、应用领域广等显著优势而备受学界关注。基于此,本文开展了对有机空心粒子的主要制备策略的论述,并对比分析了制备策略的优势及局限性;而后对微米级、纳米级以及微/纳多尺度结构有机空心粒子构造成形及形貌调控的研究进展进行了全面综述;最后,对微/纳米级有机空心粒子在药物载体、催化、传感、储能等领域的应用进展进行了细致阐述,并对其构造方式及发展趋势进行了展望。

柿庄北煤层气区块煤层压裂裂缝扩展规律及影响因素

揭示煤层气储层压裂裂缝扩展规律及影响因素,对于制定压裂工艺及高效开发煤层气资源具有重要的意义。利用沁水盆地柿庄北煤层气区块的钻井取心、测井、井下节理观测、压裂施工及微震监测等数据,系统分析了水力压裂裂缝扩展规律及影响因素。结果表明:研究区主要采用清水压裂液,压裂施工曲线可分划为上升型、下降型、平稳型和波动型4类;微震监测表明压裂裂缝走向主要在37°~55°和42°~70°,压裂裂缝网络长度范围在69.5~157.5 m,宽度在35.0~68.5 m。Ⅰ型地应力(σ_(v)>σ_(H)>σ_(h))状态下,压裂裂缝容易沿着垂向扩展,多数压裂曲线为下降型或稳定型;Ⅱ型地应力(σ_(H)>σ_(v)>σ_(h))状态下,压裂裂缝扩展方向相对单一,多数为单一形状的垂直裂缝,裂缝网络宽度较小;Ⅲ型地应力(σ_(H>σ_(h)>σ_(v))状态下,压裂裂缝沿水平方向扩展,裂缝形态复杂。侧压系数λ与压裂裂缝网络长度呈正相关关系,与压裂裂缝网络宽度呈负相关;若λ大于0.3,压裂裂缝网络长度常大于90 m。压裂裂缝扩展到节理(裂隙)时能够出现穿越、沟通和俘获3种类型;其中沟通型压裂效果较好,多数煤层气井具有高产稳产的特点;穿越型的压裂裂缝延展长度有限,俘获型的压裂裂缝多数与节理(裂隙)重合,这2类压裂井的产气效果相对较差。随着原生+碎裂结构煤占比的增大,压裂裂缝网络长度逐渐增大,宽度逐渐减小;当原生+碎裂结构煤厚度占比小于40%,压裂裂缝网络长度难以超过110 m。上述成果可为煤层压裂改造提供理论基础及地质保障。

乳化植物甾醇对福建白兔生长性能、肠道形态及盲肠菌群与代谢物的影响

本试验旨在研究乳化植物甾醇对福建白兔生长性能、肠道形态及盲肠菌群与代谢物的影响。选取健康、体重相近的40日龄福建白兔150只,随机分为5组,每组30只(公母各占/1/2),单笼饲养。对照组饲喂基础饲粮,试验组A在基础饲粮中添加20 mg/kg的普通植物甾醇,试验组B、C、D在基础饲粮中分别添加10、20和40 mg/kg的乳化植物甾醇,试验期为60 d。饲养试验结束后采样,测定各组的生长性能和肠道形态、盲肠菌群组成与代谢物组成及相对含量。结果显示:1)与对照组和试验组A相比,试验组B、C、D福建白兔的腹泻率和死亡率明显下降,平均日采食量、平均日增重、料重比等各项生长性能指标均有一定程度的改善,其中试验组C的平均日增重、料重比与其他各组的差异达到显著水平(P<0.05)。2)与对照组相比,试验组C的十二指肠绒毛长度与试验组B、C的空肠绒毛长度显著提高(P<0.05),试验组A、B、C、D十二指肠的隐窝深度与试验组B、C、D空肠的隐窝深度显著降低(P<0.05),试验组A、B、C、D十二指肠和空肠的绒毛长度与隐窝深度比值(V/C值)与试验组B、C、D回肠的V/C值显著增加(P<0.05);试验组A空肠、回肠的V/C值显著低于试验组B、C、D(P<0.05);试验组C十二指肠的绒毛长度、试验组C、D十二指肠的V/C值显著高于其他各组(P<0.05)。3)试验组B、C、D盲肠菌群组成与对照组和试验组A相差较大,试验组B、C、D在门水平上以厚壁菌门(Firmi-cutes)、拟杆菌门(Bacteroidota)为主,厚壁菌门/拟杆菌门随着乳化植物甾醇添加剂量的增加呈现先增加后略微下降的趋势;在属水平上,Muribaculaceae、瘤胃球菌科NK4A214组(Ruminococ-caceae_NK4A214_group)、阿克曼氏菌属(Akkermansia)、梭菌纲UCG014(Clostridia_UCG-014)、梭菌纲vadinBB60组(Clostridia_vadinBB60_group)为各组优势菌属。4)添加植物甾醇的各试验组盲肠中糖和醇、有机酸、氨基酸等代谢物的相对含量比对照组增加,部分脂类和类脂类的相对含量下降,类激素物质的相对含量增加。Spearman相关性分析表明,这些代谢物与产粪甾醇真杆菌属(Eubacterium_coprostanoligenes)和瘤胃球菌科V9D2013组(Ruminococcaceae_V9D2013_group)密切相关。综上所述,饲粮中添加乳化植物甾醇可降低福建白兔的腹泻率和死亡率,提高平均日采食量和平均日增重,降低料重比,有利于改善肠道形态和盲肠菌群组成,增加盲肠中代谢物的相对含量,特别是短链脂肪酸;乳化植物甾醇添加剂量为20 mg/kg时对福建白兔生长性能和肠道黏膜形态完整性的改善效果最好,此剂量为福建白兔饲粮中的乳化植物甾醇的最佳添加剂量。

影响冷轧板表面转化膜形成质量因素研究

磷化膜、硅烷膜是冷轧板常见的转化膜,除自身工艺对其形成质量有很大的影响外,冷轧板表面状态及形貌对其形成质量也有很大的影响。研究了冷轧板表面残油、残碳,表面夹杂物及析出相,表面缺陷,表面合金元素偏聚,表面微观形貌表征参数等对转化膜形成质量的影响,并就转化膜对电泳漆膜耐腐蚀性能的影响及未来研究方向进行了讨论。结果表明:冷轧板表面的洁净化,表面夹杂物及析出相、偏聚元素、划痕缺陷控制的少量化,表面微观形貌表征参数控制的精细化,可以提高冷轧板转化膜的形成质量。

材料微形态与微图案加工及可视化应用

近年来微纳技术革新层出不穷,对材料微纳尺度下的形态结构进行设计与加工的精度和稳定性得到了大幅提升。在此基础上能够实现材料形态的微观可视化,这在半导体与微电子、仿生表面构筑等领域应用前景广阔。本文从纳米材料发展过程及具体分类出发,探讨其微观可视化的相关技术,并阐述了以飞秒激光为主的热点微纳加工制造方法,分析不同加工方法带来的不同材料特性差异,以及典型功能化应用。同时,藉由微形态、微图案等微观可视化的视觉艺术设计与创作内涵,开展微观艺术审美解析与探讨。

微造型形状对滑动轴承摩擦特性的影响

利用激光微造型技术在滑动轴承轴颈表面加工出三角形、圆形和正方形微造型,分析不同形状微造型化滑动轴承的摩擦特性,并表征表面形貌,研究表征参数和摩擦特性的关系。结果表明:与未造型的滑动轴承相比,随着载荷增加,微造型后滑动轴承的摩擦系数逐渐减小,三角形微造型的滑动轴承摩擦系数最小,其次是圆形,最后是正方形。当表面偏态增加,摩擦系数升高,而表面峰态增加时,摩擦系数变化正好相反;当表面谷处和中心处平均空体体积增加时,摩擦系数先降低后升高,表面谷处及中心处平均空体体积分别为6.148×10^(-4)mm^(3)和5.418×10^(-3)mm^(3)时,摩擦系数最低;当表面峰和谷平均体积增加时,摩擦系数降低。在载荷3200 N及600 r/min时,微造型后滑动轴承的摩擦系数随着连通性系数的增加而降低。

石墨烯-PAN基复合纳米纤维的微观形貌及其抗菌性能

为了优化GO-PAN基复合纳米纤维的制备方法,探究石墨烯的质量分数对复合纳米纤维抗菌性能的影响效果,利用静电纺丝法制备了不同石墨烯质量分数的GO-PAN基复合纳米纤维,使用X射线衍射仪、扫描电子显微镜、傅里叶红外光谱、差示扫描量热仪、力学性能分析等对复合纳米纤维的宏观性能和微观结构进行表征。研究结果表明:石墨烯的添加降低了复合纳米纤维的结晶度,GO-PAN基复合纳米纤维微观上呈三维网状结构,纳米纤维无序交错排列,纤维直径为170~230 nm。随着石墨烯质量分数的增加,复合纳米纤维的拉伸强度先增大后降低,断裂延伸率持续降低,且当石墨烯质量分数增大至0.9%时,复合纤维的拉伸强度达到了最大值20.61 MPa;石墨烯的添加改善了复合纳米纤维热学性能,脱水温度提高。GO-PAN基复合纳米纤维对大肠杆菌和金黄色葡萄球菌的抑菌率均超过了95%,且石墨烯质量分数0.9%的复合纳米纤维膜对2种菌种的抑菌效率均达到最大值,抑菌率分别为97.32%、99.85%,其中复合纳米纤维膜对金黄色葡萄球菌的抑菌效率高于大肠杆菌。

高地温对超细复合掺合料胶凝体系的影响

通过实验室近似模拟高海拔地区高地温环境,研究超细复合掺合料对水泥基胶凝材料力学性能、体积稳定性、孔结构的影响,分析在不同温度下超细复合掺合料对水泥的最优取代率,结合微观手段分析超细复合掺合料最优掺量时胶凝体系的反应机理。结果表明:掺加超细复合掺合料能提高水泥基胶凝材料的力学性能,随着养护龄期的延长,最优取代率的抗压强度能够提高10%~21%,在高温下强度增长缓慢;超细复合掺合料体系的收缩率表现优于纯水泥体系,在适当高温环境下可保持体系稳定,但80℃的养护温度会增大体系的体积收缩率;超细复合掺合料能降低体系的平均孔径,提高密实度,生成更多钙矾石、水化硅酸钙等水化产物。

考虑材料塑性流动的粗糙表面弹塑性接触建模

针对粗糙表面弹塑性接触问题,考虑微凸体顶端因接触变形产生的材料塑性流动,从塑性变形体积守恒准则出发,将相邻接触单元划分为不同类型接触片段,对不同类型接触片段分别提出了材料塑性流动模式与算法,建立了表面微观形貌循环更新的弹塑性接触模型。通过与Hertz解和有限元解进行对比,检验了所提模型的有效性。应用所提模型开展粗糙表面弹塑性接触分析,获得了表面微观形貌和接触压力演化过程。结果表明:所提模型与Hertz解和有限元解基本相符,最大误差在10%以内;材料塑性流动使得材料由峰顶逐渐向峰谷转移,导致接触范围随之变大,平均接触压力随之减小,但转变速度逐渐趋缓。

凤眼果的生药学研究

凤眼果具有温胃、杀虫等功效,其名称和性状易与苹婆属其他物种混淆,然而其相关研究基础比较薄弱。该研究对凤眼果性状、微性状、种子横切面及粉末显微特征进行观察;利用双向测序获取凤眼果DNA条形码序列ITS2、psb A-trn H、mat K、rbc L,计算Kimura 2-Parameter(K2P)遗传距离,建立邻接系统进化树并进行聚类分析。结果表明:(1)凤眼果性状特征为外被深红色果皮,种子表面红褐色或暗栗色,质硬,内含浅黄色肥厚胚乳2片。(2)微性状特征为外种皮红褐色,极薄,质脆;中种皮黑褐色,较厚,质硬;内种皮浅黄色,质软。(3)显微特征为外种皮石细胞结构和排列方式、中种皮栅状细胞结构、内种皮细胞壁呈连珠状增厚、草酸钙簇晶。(4)基于ITS2序列可将凤眼果与苹婆属其他植物有效区分,mat K序列可将假苹婆与苹婆属其他植物有效区分。该研究获取的凤眼果性状、微性状及显微特征数据,结合ITS2条形码序列可有效鉴别凤眼果,为其资源开发及质量标准制定提供了科学依据。