纵向无刻痕一体化竹展平技术解析

基于现有“刻痕”和“扎眼”等有损伤竹展平技术,通过对圆竹定段、壁厚分级、锯切剖分、分段软化、定弧定厚微整形、一体化展平和多段干燥等工序的技术创新,实现了竹材纵向无刻痕一体化展平,制得的竹展平板表观质量好,力学性能优良,板材出材率高。结合该技术在工厂的实际应用情况,缩短软化和展平时间,实现高温条件下快速展平及提高各生产工序之间的连续化水平,进一步提升板材质量和降低生产成本,将成为今后的研究重点。     

Trends of Yield and Soil Fertility in a Long-Term Wheat-Maize System

The sustainability of the wheat-maize rotation is important to China＇s food security. Intensive cropping without recycling crop residues or other organic inputs results in the loss of soil organic matter （SOM） and nutrients, and is assumed to be non- sustainable. We evaluated the effects of nine different treatments on yields, nitrogen use efficiency, P and K balances, and soil fertility in a wheat-maize rotation system （1991-2010） on silt clay loam in Shaanxi, China. The treatments involved the application of recommended dose of nitrogen （N）, nitrogen and phosphorus （NP）, nitrogen and potassium （NK）, phosphorus and potassium （PK）, combined NPK, wheat or maize straw （S） with NPK （SNPK）, or dairy manure （M） with NPK （M1NPK and M2NPK）, along with an un-treated control treatment （CK）. The mean yields of wheat and maize ranged from 992 and 2 235 kg ha-1 under CK to 5 962 and 6 894 kg ha-1 under M2NPK treatment, respectively. Treatments in which either N or P was omitted （N, NK and PK） gave significantly lower crop yields than those in which both were applied. The crop yields obtained under NP, NPK and SNPK treatments were statistically identical, as were those obtained under SNPK and MNPK. However, M2NPK gave a significant higher wheat yield than NP, and MNPK gave significant higher maize yield than both NP and NPK. Wheat yields increased significantly （by 86 to 155 kg ha-1 yr-1） in treatments where NP was applied, but maize yields did not. In general, the nitrogen use efficiency of wheat was the highest under the NP and NPK treatments; for maize, it was the highest under MNPK treatment. The P balance was highly positive under MNPK treatment, increasing by 136 to 213 kg ha-1 annually. While the K balance was negative in most treatments, ranging from 31 to 217 kg ha^-1 yr^-1, levels of soil available K remained unchanged or increased over the 20 yr. SOM levels increased significantly in all treatments. Overall, the results indicated that combinations of organic manure and inorganic nitrogen, or retuming straw with NP is likely to improve soil fertility, increasing the yields achievable with wheat-maize system in a way which is environmentally and agronomically beneficial on the tested soil.     

分级竹层积材的湿胀性研究

竹材是一种变异性非常显著的天然材料,本文采用分级方法研究了竹层积材的吸水膨胀率。结果表明：竹层积材是一种低湿胀性材料,顺纹、径向和弦向上均远低于木材和LVL。经过对竹木材构造的分析,解释了竹层积材低湿胀性的原因。利用竹层积材低湿胀性的特点,可以开发湿环境和干湿交替环境下使用的系列产品。     

Traits Related to Chilling-Induced Photoinhibition in Leaves of indica and japonica Rice (Oryza sativa)

Physiological indices related to PS Ⅱ photochemical efficiency (Fv/Fm) and membrane lipid peroxidation were measured in leaves of indica rice cv Shanyou 63 and japonica rice 9516 at different temperatures and light intensities for four days. No obvious changes in Fv/Fm and MDA were observed in both indica and japonica rice at moderate temperature and medium PFD,implying neither photoinhibition nor photooxidation happened in these cases. In indica rice either at medium temperature with higher PFD or at lower temperature with medium PFD Fv/Fm dropped obviously with no changes in MDA contents, and photoinhibition appeared while photooxidation did not occur. However, D1 protein, Fv/Fm, (A Z)/(A Z V), and SOD activities dropped, and O2 -. production and MDA content increased accordingly, as well as both photoinhibition and photooxidation appeared in two rice varieties at lower temperature and higher PFD. Experiment with inhibitors at lower temperature and higher PFD showed that as compared with japonica rice the decrements appeared in D1 protein contents, SOD activities, and (A Z)/(A Z V) ratios, the xanthophyll cycle and non-photochemical quench (qN) were inhibited in a more degree, as well as increments of MDA content were greater, thus exhibiting more distinct photoinhibition and photooxidation in indica rice. It is suggested that Fv/Fm and membrane lipid peroxidation product-MDA were the key indices to predict and diagnose photooxidation.     

铁的生理功能与富铁水稻的研究进展

简述了铁的生理功能以及人体缺铁后的主要病症,对稻体中铁含量及其生物有效性以及铁在稻体中富集的分子机理,外源物质对铁富集的影响和富铁水稻品种的选育等方面的研究进展进行了综述,并对今后富铁水稻选育的研究方向进行了展望。     

人工林木材材性预测研究进展

为解决人工林定向培育与木材加工利用相脱节的状况,木材材质预测逐渐成为人工林培育科学与木材科学领域研究的中心问题之一.系统地总结了人工林木材材性预测的方法,通过分析比较各种预测方法,以期对我国人工林木材材性预测的深入开展起到一定的借鉴意义,更好地用于指导人工林定向培育和木材加工利用.     

基于干燥时间的稻谷深床干燥工艺参数的优化

利用深床干燥试验台,通过单因素试验和三因素二次回归正交旋转组合试验,建立了热风温度、表现风速和谷层厚度对干燥时间影响的回归方程,分析各因素的单因素效应与互作效应,利用频数分析法进行优化.结果表明:含水率24%的稻谷进行深床干燥时,干燥时间小于180min的概率为95%,干燥热风温度为68～75℃,表现风速为0.58～0.67 m·s-1,谷层厚度为19～24cm,优化了稻谷干燥生产的工艺参数,为实际生产经济指标评估提供了依据.     

午间强光下籼粳杂种稻的叶黄素循环和CO2交换特性

以籼亚种３０３７、Ｐａｌｇｈａｒ和粳亚种０２４２８、０２９及其籼粳亚种间杂种Ｆ１、为材料进行试验。水稻叶片中叶黄素循环（叶黄素组分紫黄质、环氧玉米黄质、玉米黄质的含量Ｖ、Ａ、Ｚ）、Ｐｒ／Ｐｎ、非光化学猝灭、表现光合量子效率、ＰＳⅡ光化学效率和Ｄ１蛋白量有明显的日变化,且在不同基因型水稻间有显著差异。在午间强光下,与籼亚种相比,粳亚种有较高的ＡＱＹ、Ｆｖ／Ｆｍ和Ｄ１蛋白量,较低地（Ａ＋Ｚ＋Ｖ）、Ｐｒ     

竹编在家具设计中的创新应用研究

竹编工艺是我国的非物质文化遗产,探索竹编与家具更好地融合应用,既顺应国家对于可持续发展的要求,也有助于推动传统手工艺的升级。简述了竹编工艺和编织纹样种类,分别从造型、功能和文化三个方面分析了竹编工艺对家具产品的影响。同时提出竹编家具与数字化结合应用的不同形式,探寻竹编工艺在现代“互联网+”背景下的创新发展之路。     

纳米银影响桑树组培苗生长的原因初探

纳米银作为新型抗菌材料得到广泛应用,同时也通过多种途径排放入环境,在土壤和自然水体中富积,对环境微生物及植物产生毒副作用。本研究分析纳米银对桑树生长的影响。在土壤中按20mg/Kg,40mg/Kg(土壤干重)添加纳米银,对照组不添加纳米银,栽种4月龄桑树组培苗,观察桑树的生长情况。移栽4个月后对土壤中可培养细菌、真菌和放线菌进行了比较,测定纳米银在桑叶叶片、桑树木质部、韧皮部及根部的蓄积量;最后测定桑叶叶片中叶绿素含量、过氧化氢酶、过氧化物酶、硝酸还原酶等的酶活性。结果显示低浓度纳米银早期促进桑树发芽,但后期桑叶提前枯黄。添加纳米银土壤中可培养细菌、真菌和放线菌的数量均显著低于对照组。纳米银在桑树各部位的分布,根>茎>叶,木质部的含量相对衡定。桑叶中过氧化氢酶,过氧化物酶的酶活性显著高于对照组,而硝酸还原酶的活性显著低于对照组。桑叶叶绿素a和叶绿素b含量差异不显著。实验结果表明,土壤中低浓度纳米银可短期促进桑树生长,但高浓度对桑树有致死性作用。