双光子聚合加工均匀木堆结构方法的研究

由于双光子聚合所具有的纳米级加工分辨率以及真三维制造能力,被广泛应用于微米纳米制造领域。利用双光子聚合加工的三维木堆结构是实现生物支架、光子晶体、超材料等功能器件的重要途径之一。但是加工结构在经过后处理之后产生的不均匀收缩成为获得高质量木堆结构的重要阻碍,严重时会导致失去其结构的功能性。为了实现木堆结构的均匀性加工,提出一种通过降低加工结构与基底附着力的方法,来实现均匀木堆结构的加工。此外,采用Ormocomp光敏材料以及双光子聚合加工技术,对基底高附着力和低附着力的木堆结构分别进行了加工。通过对加工所得木堆结构的各层尺寸的测量,验证了所提出方法的有效性。

聚合物木堆微结构制备的研究

提出一种新的、成本低廉的方法制备大面积聚合物两层木堆结构。首先分别对刻槽硅片模板进行亲水和疏水表面处理,以形成表面自由能不同的表面。将两块表面能不同的模板微条纹垂直对齐后紧压形成微通道三维网状结构,再利用毛细管作用力分别将甲基丙烯酸甲酯、聚二甲基硅氧烷(PDMS)、苯乙烯等三种聚合物的预聚体渗透到微通道内,固化成型后冷却脱模,得到两层木堆结构。该聚合物木堆结构从低表面能模板脱离,附着于高表面能模板上。扫描电镜结果分析表明:用苯乙烯预聚体可以得到结构完整、不变形卷曲的两层木堆微结构,且层间无多余粘连层。

木堆结构三维光子晶体带隙特性

基于平面波展开法研究木堆结构三维光子晶体带隙特性。用硅材料构成木堆结构三维光子晶体,改变结构中木条的宽度和长度,得到当木堆条宽度为5μm,高度为7μm时形成的带隙结构较宽,在0.2899—0.3804Hz,带隙宽度为0.0905Hz。改变构成木堆结构三维光子晶体的材料,得到锗材料构成木堆结构三维光子晶体带隙结构在0.2585—0.3500Hz,带隙宽度为0.0915Hz,带隙相比硅材料和碳化硅材料较宽。研究结论为三维光子晶体的制备提供参考。

Effects of Bacteria and Accessories on Chicken Manure Compost

[Objective] In order to study the influence of bacteria and accessories of chicken manure compost.[Method] The experiment was conducted to investigate the changes of temperature,the quantification of Escherichia coli and the odor during chicken manure compost by adding sawdust,rice husk,yeast and lactic acid bacteria respectively.[Result] The results showed that：（1） The yeast group reached the highest fermentation temperature 67.6 ℃,which was 6.9 ℃ higher than that of lactic acid bacteria group,and the fermentation time of yeast group kept over 55 ℃for 16 days,which was 5 days longer than that of lactic acid bacteria group,both of which were better than that of control group（55.9 ℃,5 days）;（2）The highest fermentation temperature of sawdust group was 2.2 ℃ higher than that of rice husk group,and the fermentation time of sawdust group kept over 55 ℃ was 3 days longer than that of rice husk group;（3） The quantification of E.coli reduced from10^5 to 10^2per gram in both of the yeast group and the lactic acid bacteria group.The odor of the yeast group and the lactic acid bacteria group disappeared in the seventh day and the eighth day respectively.[Conclusion] The results showed that the adding of yeast and sawdust was the best condition for chicken manure composting in this experiment.

Bearing Capacity of Mixed Pile with Stiffness Core

To study load transfer mechanism and bearing capacity of a mixed pile with stiffness core （MPSC）, which is formed by inserting a precast reinforced concrete pile （PRCP）, in-situ tests involving MPSCs with different lengths, diameters, water cement ratios and PRCPs, cement mixed piles, and drilling hole piles, were carried out. Limit bearing capacities, load-settlement curves and stress distribution of MPSCs and mixed piles were obtained. The load transfer between cement soil and PRCP was analyzed by finite element method （FEM）. Test results and FEM analysis show that an MPSC has fully utilized the big friction from a cement mixed pile and the high compressive strength from a PRCP which transfers outer top load into the inner cement soil, and that inserting a PRCP into a mixed pile changes the stress distribution of a mixed pile and improves frictional resistance between a mixed pile and soil. The length and the section area on PRCP of an MPSC both have an optimum value. Adopting MPSC is effective in improving the bearing capacity of soft soil ground.

Theoretical optimization of complete forbidden bands in woodpile-type photonic crystals

Based on the plane-wave method, the optical properties of complete forbidden bands of woodpile structure photonic crystal with an entire Lattice rotation of 45° in the x-y plane were theoretically studied in terms of height-to-pitch ratios, filling factors, and rotation angles. The calculated results show that the gap to mid-gap ratio changes slightly with a filling fraction ranging from 0.25 to 0.30. The optimum height-to-pitch ratio is about 1.3. The gap to mid-gap ratio reaches more than 0.18 when the rotation angle increases from 40° to 50° and the maximum gap to mid-gap ratio of 0.2 remains unchanged for the rotation angle from 42°to 48° with a constant height-to-pitch ratio of 1.3. The gap to mid-gap ratio reaches the maximum value of 0.2 when the height-to-pitch ratio is 1.3. This woodpile-type photonic crystal can provide large band gaps within a wider parameter range, which makes it convenient to manufacture three-dimensional photonic crystals in the laboratory.

Use of Wood Fibre Compost for the Cultivation of Trichoderma sp, （Isolate Td22）

The main objective of this research was to investigate the ability of a Trichoderma sp. （Td22）, inhibitory to Sclerotinia minor Jagger, to grow and survive in mature wood fibre waste （WFW） compost of paper mill origin following nutrient amendment. The growth and survival of the fungus in the WFW compost was assessed by serial dilution plate count method followed by confirmation of the fungal identity using pectic enzyme analysis as described in Cruickshank and Pitt [1]. It was found in this study that the population densities of TdE2 achieved under non-sterile conditions in the WFW compost following nutrient amendment was approximately in the range of 7.0 lOgl0 CFU/g dw - 8.5 log10 CFU/g dw after 28 days, depending on pre-treatment. The efficacy of this WFW compost-grown TdE2 for protection of lettuce from attack by S. minor was also demonstrated in glasshouse trials. This study indicates that cellulosic paper mill waste compost could provide an abundant low-cost growth medium for the large-scale cultivation of fungal antagonists, improving prospects for cost-competitiveness with chemical treatments.

Composting Efficiency of Urban Forest Litter and River Sediment at Different Proportions

In order to explore a technology for producing organic fertilizer by composting urban forest litter and river sediment passivated by fly ash, an experiment was conducted to study dynamic changes of several parameters including temperature, pH, organic matter, C/N and germination index （GI） during high-temperature composting of urban forest litter and river sediment at five different proportions （1：1 （Ⅰ）, 1：2 （Ⅱ）, 1：3 （Ⅲ）, 2：1 （Ⅳ） and 3：1 （Ⅴ））. Results showed that the temperature and pH increased first and then decreased; at the proportion of 3：1, the temperature increased rapidly and the high-temperature duration was longest （5 d）; at the end of the composting, all the treatments reached the decomposed status, the pH ranged from 7.47 to 8.87, and the organic matter content was reduced by 36%, 38%, 42%, 33% and 29%, respectively, indicating that increasing the proportion of urban forest litter was conducive to reducing the loss of organic matter. Due to low C/N ratio of river sediment, increasing the proportion of urban forest litter was helpful to improve the efficiency of composting. The GI of treatments I, IV and V reached 80% on day 26, 18 and 19 respectively, but the GI of treatments II and III did not reach this level until the end of composting. Considering the quality of fertilizer and efficiency of composting for large-scale production, the proportion between urban forest litter and river sediment is suitable to be set as 3：1 for production of organic fertilizer.

Enhanced Growth and Yield Performance of Cassava Peel Compost and Mineral Fertilizer on Corchorus olitorius L.

Application of inorganic fertilizers improves crop yields but costs and adverse health effects often discourage their applications. This study therefore aims at evaluating the combined effects of cassava peel compost with poultry manure and mineral fertilizer on growth and yields of Corchorus olitorius. Pots （factorial laid out in a randomized complete block design） and field （split-plot with fertilizer being the main effect and the varieties the sub plot effect） experiments were carried out during rainy season at Ibadan, Nigeria. Treatments consisted of 0, 5, l0 and 20 t/ha composts prepared from cassava peel and poultry manure in ratio 3：1 and mineral fertilizer （NPK 15：15：15） at the rate of 250 kg/ha, using two varieties of C. olitorius. Five and six weeks after planting （WAP）, plants were assessed for growth and yields in pot and field experiments respectively, and also in residual studies. Application of compost significantly improved growth （heights） （36.50-41.56 cm）, while morphological and dry weight values increased with increase in compost. Marketable yield increase of 13.2%, 22.3%, 32.1% and 29.3% were recorded using 5, 10, 20 t/ha compost and NPK fertilizer respectively in the field. Corresponding increase when ratooned were 40.0%, 42.9%, 57.1% and 52.0%, respectively. Application of compost at the rate of 20 t/ha performed better in the main and residual effect experiments compared to NPK fertilizer and other compost rates. Application of cassavas peels compost at the rate of 20 t/ha proved to be adequate for optimum growth and yield performance of C. olitorius.

3D打印β-TCP/HA/PLA骨移植支架材料的研究

目的 制备个性化的3D打印骨移植支架修复材料,以满足骨缺损患者的需求.方法 运用计算机软件CAD设计出三维木堆结构的模型图,通过三维气浮运动平台,使用3D打印方法模拟出三维木堆结构的复合β-磷酸三钙（β-TCP）、羟基磷灰石（HA）和聚乳酸（PLA）材料的支架.再对支架材料进行抽真空热处理,X射线能谱仪检测其氯仿残留量,扫描电镜观察支架材料的表面形貌,最后用噻唑蓝（MTT）法检测支架材料对人SV40转染成骨细胞hFOB1.19的毒性.结果 当打印浆料的挤出气压在137.9～413.7kPa内,可打印出β-TCP/HA/PLA三维骨移植支架材料.成型后的三维骨移植支架材料经90℃保温抽真空处理及150℃热处理后能消除其中的氯仿;材料表面粗糙,拥有表面细孔和内部连通的微孔;其同hFOB1.19细胞共培养7d,细胞毒性等级为0级.结论 本研究制备的3D打印β-TCP/HA/PLA骨移植支架材料表面粗糙而具有通孔,利于成骨细胞的培养,且骨诱导作用明显,体现出3D打印在制备骨移植多孔材料上拥有很大的优势和发展前景.

换锄把

锄把坏了,得换根新的。王婶留下'命令',挑根好的木把换上,桉木的太容易坏了。王叔在一堆木堆上找来找去只找到一根适合做锄把的桉木棍儿,只能是这根啦。王叔拿刀把木棍上的疙瘩眼儿削平,把木棍上其他哪怕稍微有点硌手的地儿也削平。木棍看起来基本上赏心悦目了,除了棍梢处那一点弯。不过这也比那根'年老体衰'的锄把没坏时强多了.

Aromatic Moieties from Matured Chicken Manure and Agriculture Residues Compost Suppress Growth of Lepidium sativum L. and Trichoderma harzianum

To better understand the role of organic matter(OM)prepared from chicken manure and agriculture residues compost on the growth of plants(Lepidium sativum L.)and antagonistic fungi(Trichoderma harzianum),we analyzed the structure and composition of extracted OM using fluorescence excitation-emission matrix(EEM)spectroscopy and solid-state13C cross-polarization magic-anglespinning nuclear magnetic resonance(13C CPMAS NMR)spectroscopy.The results showed that the EEM contours of water-extracted OM(WEOM)and alkali-extracted OM(AEOM)were similar.Furthermore,solid-state13C CPMAS NMR spectroscopy demonstrated that water extraction could not proportionally pull out aromatic moieties(112–145 ppm)from compost,but the alkali method in proportion extracted both carbohydrates(65–85 ppm)and aromatic moieties.The results suggest that AEOM may better reflect the bulk OM composition of compost,and one should be cautious when applying WEOM as an alternative indicator of total compost OM.Further investigations demonstrated that,compared to carbohydrates,aromatic moieties played a predominant role in growth suppression of Lepidium sativum L.seeds and Trichoderma harzianum.

Optimization of enzymatic hydrolysis of cassava to obtain fermentable sugars

This work evaluates the enzymatic hydrolysis of starch from cassava using pectinase,α-amylase,and amyloglucosidase.A central composite rotational design(CCRD)was carried out to evaluate the effects of amyloglucosidase,pectinase,reaction time,and solid to liquid ratio.All the experiments were carried out in a bioreactor with working volume of 2 L.Approximately 98%efficiency hydrolysis was obtained,resulting in a concentration of total reducing sugar released of 160 g/L.It was concluded that pectinase improved the hydrolysis of starch from cassava.Reaction time was found to be significant until 7 h of reaction.A solid to liquid ratio of 1.0 was considered suitable for hydrolysis of starch from cassava.Amyloglucosidase was a significant variable in the process:after its addition to the reaction media,a 30%-50%increase in the amount of total reducing sugar released was observed.At optimal conditions the maximum productivity obtained was 22.9 g/(L.h).