稻草原料酸碱性及稻草中密度纤维板的性能

测试分析了稻草原料的ｐＨ值和缓冲容量，分别使用脲醛树脂胶和异氰酸酯胶在特定工艺条件下压制了稻草中密度纤维板，并测试了板材性能。结果表明：１）稻草秸秆原料呈弱碱性，缓冲容量远高于普通木材；经热磨处理获得的稻草纤维呈弱酸性，其缓冲容量虽较稻草秸秆有一定幅度的下降，但仍高于普通木材；２）脲醛树脂或异氰酸酯稻草中密度纤维板的性能都明显优于相应的碎料板；在密度０．８０ｇ／ｃｍ３和施胶量１７％的条件下，脲醛树脂稻草中密度纤维板性能达到国标ＧＢ／Ｔ１７６５７－１９９９一等品的要求，在密度０．８０ｇ／ｃｍ３和施胶量６％的条件下，异氰酸酯稻草中密度纤维板性能达到国标ＧＭ／Ｔ１７６５７－１９９９优等品要求。     

微波处理对稻草表面特性的影响

利用FEIXG型电子自旋共振波谱仪和Nicolet Nexus 670型傅立叶变换红外光谱仪(FTIR)研究了微波处理对稻草表面特性的影响。研究结果表明,经微波处理后的稻草表面自由基浓度显著增加,最高可以达到处理前自由基浓度的7倍左右。且随着处理时间的延长和微波强度的增加,稻草表面自由基浓度的增加幅度有所上升。经微波处理后,稻草外表面的化学成分(包括SiO2、羟基、木素和纤维素)变化都不明显,而稻草内表面SiO2略有减少,羟基显著增加,木素和纤维素也有一定变化。微波处理可以改善稻草内表面的特性,使之比外表面更具活性,有利于稻草与胶黏剂之间的交联。     

机械粉碎处理对稻麦秸秆界面特征的影响

对比两种原料稻草和麦秸分别经机械粉碎前后其界面特征因子,包括表面形貌、表面化学官能团、表面自由基及表面自由能等的变化.研究结果表明:稻草比麦秸更易机械破碎,扫描电镜(SEM)观察显示两种原料本身均存在完整的表面形貌,而经过球磨机机械粉碎后碎料均出现了很明显的断裂、撕裂及起毛现象,且内部细胞结构明显暴露.稻草外表面纤维素和木质素的特征峰均较弱,尤其是3200cm-1处的羟基峰几乎没有;电子自旋共振波谱(ESR)分析表明,碎料的自由基峰强度明显高于其相应的秸秆,在温度为100～200℃的范围内,随着温度的升高,各表面自由基峰强度明显增加;表面自由能的研究结果则表明, 麦秸表面自由能要高于稻草,碎料的表面自由能要高于各自的秸秆;使用6%异氰酸酯作为胶黏剂生产的两种秸秆碎料板性能均达到国家标准GB 4897.3-2003要求,且麦秸碎料板的性能更佳.     

改性酚醛树脂胶黏剂压制稻秸秆人造板的研究

针对稻秸秆难胶接的结构特性,笔者主要从两方面进行了较系统性的探索.一是对酚醛树脂进行改性;二是对稻秸秆表面进行预处理.以稻秸板静曲强度、内结合强度和2h吸水厚度膨胀率为目标,用蒸煮、稀碱溶液等方法处理稻草,并用电子显微镜观察稻草表面的变化,在胶黏剂中添加改性剂二甲基硅油和硅烷偶联剂,研究各种处理方法及改性剂用量对板材性能的影响.结果表明:2%二甲基硅油作为共聚改性剂,1%硅烷偶联剂,采用1%碱溶液表面喷洒进行预处理,并在秸秆中加入15%的木屑,参照GB/T 4897.3-2003标准,稻秸秆人造板的各项指标得到明显改善.     

动态挤压法稻草机械浆生产与应用

在生产线上，将热水浸渍后的稻草用双辊磨动态挤压磨解，制取机械浆，配用废纸抄造瓦楞原纸．为稻草资源利用开辟一条新途径。动态挤压的揉搓作用，使稻草纤维分离、变形，成纸后具有一定强度，生产废水易于处理。     

原料表面碱液处理对稻草碎料板力学性能的影响

在实验室条件下探索了稻草原料表面碱液处理对稻草碎料板力学性能的影响.试验表明,处理后的稻草碎料板的内结合强度比处理前有大幅度提高,弯曲弹性模量和静曲强度比处理前则有所下降,但都达到了相关的国家标准;2h吸水厚度膨胀率升高,超过国家标准.因此稻草表面碱液处理提高了稻草原料表面润湿性和胶合强度,但对稻草碎料板的力学性能有影响.     

稻草中密度纤维板用改性脲醛树脂的研究

对比三聚氰胺、二甲基硅油、硅树脂和偶联剂KH-550四种改性剂改性的脲醛(UF)树脂性能的差别及其对稻草中密度纤维板性能的影响,并进行经济评价,最终确定适用于稻草纤维板的改性UF树脂的工艺条件,同时借助于红外光谱(FT-IR)和差热扫描分析(DSC)研究最佳改性UF树脂的结构和固化特性.结果表明,三聚氰胺改性脲醛(MUF)树脂不论是对树脂性能、板性能改善还是从成本分析方面均为稻草纤维板最佳的胶黏剂,FT-IR显示出与未加三聚氰胺相比,加入三聚氰胺后树脂的羟甲基含量降低了10 %,DSC分析则表明其峰值温度有较大幅度的提高,但放出的热量较少.加入三聚氰胺改性的UF树脂其表面张力变小.     

碱化处理对稻草板表面吸收性能的影响

采用pH值8~14的氢氧化钠溶液,对不同密度的稻草板试件进行碱化处理,测定处理后试件表面对蒸馏水、甘油、酒精等3种液体的吸收性能。结果表明:经过处理,稻草板对3种液体的表面吸收性能均增强,且随着处理溶液pH值的增大而增强。稻草板碱化处理溶液适宜的pH值为7~11,可提高其表面吸收性能,有利于后续表面加工。     

轻质建材——稻草板

目前，一个中等城市粘土实心砖使用量平均在12亿块左右，年耗标煤12万吨，侵食耕地约300亩。全国建筑面积20亿平方米，年耗标煤11亿吨，年侵食耕地约12万亩，砖瓦企业生产占用的土地更为惊人。同时，我国是农业大国，农作物秸秆资源丰富，每年产生秸秆量约4亿吨之多。秸秆的处理在我国已经造成一系列问题，如何解决它是当今各界人士非常重视的问题。以稻草、麦草作原料，直接制成稻草板，用作墙体材料，可解决占用土地烧砖对耕地的侵蚀以及稻草焚烧造成的空气污染，同时也为秸秆的处理提供了有效途径。新型墙体材料可节约能源，保护耕地，保护自然环境资源，改善和促进建筑业和建材业技术进步。国务院十分重视墙体材料的革新，从2003年6月就限制使用粘土实心砖，提倡推广环保型绿色建材。     

碱液处理对稻秸表面及稻草板性能的影响

通过对不同碱液处理的稻秸表面接触角的测量和环境扫描电镜的观察得出：经过碱液处理后稻秸表面的润湿性得到改善,接触角均随处理时间的延长而降低。从稻秸表面微观特征上看,氨基钠和氢氧化钠处理效果较好,氢化钙不理想（稻草表层出现了大量的晶体物质）。压板检测稻草板力学性能的结果表明,用质量分数1％的NaNH2处理10min效果较好。     

Improvement mechanism of bondability in UF-bonded reed and wheat straw boards by silane coupling agent and extraction treatments

The effects of silane coupling agents and extractives on the wettability of reed and wheat straws were investigated. The inherent wettability of these materials was low but could be significantly improved by treating with silane coupling agents. The degree of improvement achieved by each silane coupling agent was different: Vinyl silane had almost no effect on wettability, epoxide silane was found to be more effective for reed straw, and amino silane was better for wheat straw. The wettability of these materials could also be improved by ethanol-benzene extraction, which resulted in more improvement in wheat straw than reed straw. The analyses of untreated reed and wheat straws by electron spectroscopy for chemical analysis (ESCA) revealed that there was much silicon on both the outer and inner surfaces of the former but only on the outer surface of the latter. The influence of hot-water extractives and silane coupling agents on the gelation time and pH of urea formaldehyde (UF) resin was also examined. The addition of extractives was found to increase the gelation time. Amino silane greatly retarded the gelation of OF resin, whereas epoxide and vinyl silanes had no influence on resin gelation. This retardation was found to be due to an increase in the pH of the resin.     

In vitro screening of angiotensin I-converting enzyme inhibitors from Japanese cedar (Cryptomeria japonica)

Screening and isolation of angiotensin I-converting enzyme (ACE) inhibitors from Japanese cedar (Cryptomeria japonica) based on the in vitro ACE inhibitory assay were attempted. The ethanol extract from outer bark showed the highest inhibitory activity (IC₅₀ is 16g/ml) among 24 extracts prepared from roots, leaves, heartwood, sapwood, inner bark, and outer bark by successive extraction with four solvents. The fractionation of the outer bark ethanol extract followed by the bioassay resulted in the isolation of two strong ACE inhibitors, catechin and dimeric procyanidin B3. The bioassay of three flavan-3-ols including (+)-catechin and six flavones revealed that most of these compounds have high ACE inhibitory activity. The results suggest that the phenolic hydroxyl group at the C7 position and heterocyclic oxygen atom of these compounds are important for expressing the inhibitory activity.     

Reactivity of secondary hydroxyl groups in methylβ-d-xylopyranoside toward aβ-o-4-type quinone methide

Methyl-d-xylopyranoside was allowed to react with-O-4-type quinone methide without a catalyst to elucidate the reactivities of secondary hydroxyl groups at the C2, C3, and C4 positions. Benzyl ether-type lignin-carbohydrate complex (LCC) compounds linked at the C2 and C4 positions were predominant, at a ratio of 23. However, the reactivity of the hydroxyl group at the C3 position was quite low. These results strongly suggest that the reactivity of the C2 hydroxyl group in xylan toward quinone methide intermediate is higher than that of the C3 hydroxyl group during biosynthesis of LCCs.     

Alley cropping rice (Oryza sativa var.Barafita) with cassia (Cassia siamea): soil fertility and crop production

Rice grain weight and quality (weight of larger size fractions), soil pH, and N, P, K and organic matter content were studied where rice was alley cropped with cassia on a semiarid site in The Gambia. The four treatments, control (no cassia prunings or inorganic fertilizer added), only prunings added, prunings plus half the recommended fertilizer rate and prunings plus full recommended rate of fertilizer, were applied in a Latin square design with 10×8 m plots, each sub-divided into two 4-m wide alleys. Fertilizer was applied twice; full rates were 93.7 kg/ha NPK (8:24:24) plus 32.4 kg/ha urea followed two weeks later by 100 kg/ha urea applied as side dressing. Soil samples collected before and after cropping at 0–10 cm and 10–15 cm depths and cassia pruning samples were analyzed for pH, N, P, K and organic matter content.Our results do not show significant benefit of cassia prunings applied as mulch to grain weight or quality in alley cropping rice with cassia. The addition of inorganic fertilizer plus cassia prunings did not increase rice grain and straw weights (p=0.3447 and p=0.0691, respectively) compared to the control and prunings only treatments. In all treatments, the outer rows, those within 80 cm of hedgerows, produced significantly less grain (p=0.0002) and straw than inner rows. Neither the larger grade A nor the smaller grade B grain weights were significantly different (p=0.6017 and p=0.0629, respectively) between treatments. Weight of grain, straw, and larger grade A and smaller grade B quality grain did not differ significantly for inner and outer rows (p=0.6329, p=0.7148, p=0.7171 and p=1.000, respectively).     

“I-214杨”心材、边材木质素的红外光谱、质子和碳-13核磁共振波谱特征研究

对从杨树心、边材提取的磨木木质素进行了元素分析和红外光谱（FTIR）质子和碳－13核磁共振波谱（^1H,^13C NMR)等化学特征研究。研究结果表明：杨树心、边材木质素的经验式分别为C9H7．16O2．38（OCH3）1．99和C9H8．61O2．73（OCH3）1．33。心材木质素甲氧基含量28．16％,比边材高8．73％。两种木质素均具有典型阔叶材的特征,化学结构类型基本一致,碳骨架结构基本相同,但化学官能团和键型的组成上存在差异。     

微波等离子体处理西南桤木表面的ESR和XPS分析

采用电子顺磁共振波谱 (ESR)和X射线光电子能谱 (XPS)技术 ,分析了微波等离子体处理前后西南桤木木材表面的性质。ESR图谱分析表明 :经过微波等离子体处理后 ,木材表面可迅速有效地产生大量的自由基 ;XPS图谱分析表明 :微波等离子体处理使木材表面O C原子比增加 ,C1 含量降低 ,而C2 、C3含量增加 ,并有C4 的出现。这些结果表明经微波等离子体处理后木材表面产生了大量的含氧官能团或过氧化物     

Influence of canopy light environment and nitrogen availability on leaf photosynthetic characteristics and photosynthetic nitrogen-use efficiency of field-grown nectarine trees

Relationships between CO(2) assimilation at light saturation (A(max)), nitrogen (N) content and weight per unit area (W(A)) were studied in leaves grown with contrasting irradiances (outer canopy versus inner canopy) and N supply rates in field-grown nectarine trees Prunus persica L. Batsch. cv. Fantasia. Both A(max) and N content per unit leaf area (N(A)) were linearly correlated to W(A), but leaves in the high-N treatment had higher N(A) and A(max) for the same value of W(A) than leaves in the low-N treatment. The curvilinear relationship between photosynthesis and total leaf N was independent of treatments, both when expressed per unit leaf area A(maxA) and N(A)) and per unit leaf weight (A(maxW) and N(W)), but the relationship was stronger when data were expressed on a leaf area basis. Both A(maxA) and N(A) were higher for outer canopy leaves than for inner canopy leaves and A(maxW) and N(W) were higher for leaves in the high-N treatment than for leaves in the low-N treatment. The relationship between A(max) and N resulted in a similar photosynthetic nitrogen-use efficiency at light saturation (A(max)NUE) for both N and light treatments. Photosynthetic nitrogen-use efficiency was similar among treatments throughout the whole light response curve of photosynthesis. Leaves developed in shade conditions did not show higher N-use efficiency at low irradiance. At any intercellular CO(2) partial pressure (C(i)), photosynthetic CO(2) response curves were higher for outer canopy leaves and, within each light treatment, were higher for the high-N treatments than for the low-N treatments. Consequently, most of the differences among treatments disappeared when photosynthesis was expressed per unit N. However, slightly higher assimilation rates per unit N were found for outer canopy leaves compared with inner canopy leaves, in both N treatments. Because higher daily irradiance within the canopies of the low-N trees more than compensated for the lower photosynthetic performances of these leaves compared to the leaves of high-N trees, daily carbon gain (and N-use efficiency on a daily assimilation basis) per leaf was higher for the low-N treatment than for the high-N treatment in both outer and inner canopy leaves.     

木聚糖酶预处理对麦草化学机械浆可漂性及白度的改善

探讨了以玉米芯片为碳源制备木聚糖酶及麦草化学机械浆经该木聚糖酶预处理后可漂性和白度的改善效果。结果表明，直接以玉米芯为底物、里氏木霉为菌种产酶效果较好，当底物浓度为18g/L时，木聚糖酶活力可达38．34IU／mL。木聚糖酶预处理有利于改善麦草化机浆的可漂性，促进其过氧化氢漂白，有提高漂白浆白度，降低漂剂消耗。研究表明，当经单段H2O2漂至相同白度时，木聚糖酶预处理后可节约50％的H2O2用量。若麦草CMP酶处理后采用高浓度两段过氧化氢漂白，即XP3P3漂序（H2O2总量为6％0时，白度可达60％（ISO）以上。     

麦秸秆外表面膜及异氰酸酯对麦秸与LDPE界面结合的影响

采用物理及力学性能以及界面结合形态分析相结合的方法,研究了麦秸秆外表面膜及异氰酸酯(PAPI)对麦秸与低密度聚乙烯(LDPE)两相界面结合的影响.研究结果表明:1.3% PAPI可显著提高麦秸/回收LDPE复合材料干态及 2h 沸水后内结合强度、静曲强度及弹性模量,对24h 吸水厚度膨胀率的降低改善不大;麦秸秆外表面膜具有改善麦秸与LDPE两相界面结合作用;PAPI可将麦秸与回收LDPE、麦秸秆外表面与新LDPE两相界面由相分离转变为相连续.PAPI具有有效改善麦秸与LDPE两相界面结合强度的作用.