Wood Plastic Composites Prepared from Biodegradable Poly(butylene succinate) and Burma Padauk Sawdust (Pterocarpus macrocarpus): Water Absorption Kinetics and Sunlight Exposure Investigations

Wood plastic biocomposites of biodegradable poly(butylene succinate) (PBS) and Padauk sawdust was successfully prepared by using a twin screw extruder and an injection molding machine.The effects of water absorption and sunlight exposure on some properties of the composites were investigated.Water absorption of PBS composites was found to follow the Fick's law of diffusion,while the diffusion coefficient increased with increasing wood content.Maximum water absorption of around 4.5％ was observed at 30 wt.％ sawdust.Optical micrograph indicated the swelling of wood particles by around 1％-3％ after 30 days of water immersion.The tensile and flexural strengths reduced slightly both under the water immersion and sunlight exposure.After 90 days of exposure,the composites clearly looked paler than the non-weathered ones.Thermal scan indicated the reduction of crystalline region due to the plasticization effect derived from water molecules.     

杉木人工林木材力学性质与纤维形态关系的研究

应用正交试验设计方法对不同林龄、立地条件和林分密下杉木人林木材力学性质,纤维形态的测定结果为基础,采用多元线性回归方法,对杉木人工林木材力学性质与纤维形态的关系进行相关分析和回归分析,结果表明：杉木人工林木材顺纹抗压强度,抗弯强度等十一项力学性质指标与纤维长度,纤维宽度、壁厚、腔径、壁腔比之间存在极显著的相关关系。     

香椿木材解剖构造及其物理力学性质

为扩大和培育香椿资源和填补国内经济建设及人民生活对优质木材的需求,为其开发和利用提供一定的基础数据及科学的理论指导,依照GB1927-91实验方法对其木材的解剖和物理力学性质做了系统研究。结果表明：香椿纤维13年生后形态均匀,长宽比46.18,双壁厚11.00μm,纤维壁腔比0.56,腔径比0.76;导管分子平均长度383.52μm,宽度143.98μm;基本密度和气干密度分别为0.415g/cm3和0.475g/cm3,属“轻”型;差异干缩为1.93;木材的抗弯强度、抗弯弹性模量和顺纹抗压强度分别为67.85MPa、6179.82MPa和38.23MPa,综合强度106.08MPa,均属“低”级,香椿的综合品质系数为2556.1×105 Pa,为高等级材。综合分析表明香椿材质优良。     

Effects of Grain Boundaries and Surfaces on Electronic and Mechanical Properties of Solid Electrolytes

Extended defects, including exposed surfaces and grain boundaries (GBs), are critical to the properties of polycrystalline solid electrolytes in all-solid-state batteries (ASSBs). These defects can alter the mechanical and electronic properties of solid electrolytes, with direct manifestations in the performance of ASSBs. Here, by building a library of 590 surfaces and grain boundaries of 11 relevant solid electrolytes—including halides, oxides, and sulfides— their electronic, mechanical, and thermodynamic characteristics are linked to the functional properties of polycrystalline solid electrolytes. It is found that the energy required to mechanically “separate” grain boundaries can be significantly lower than in the bulk region of materials, which can trigger preferential cracking of solid electrolyte particles in the grain boundary regions. The brittleness of ceramic solid electrolytes, inferred from the predicted low fracture toughness at the grain boundaries, contributes to their cracking under local pressure imparted by lithium (sodium) penetration in the grain boundaries. Extended defects of solid electrolytes introduce new electronic interfacial states within bandgaps of solid electrolytes. These states alter and possibly increase locally the availability of free electrons and holes in solid electrolytes. Factoring effects arising from extended defects appear crucial to explain electrochemical and mechanical observations in ASSBs.     

Preparation and Characterization of Chemically Modified Silk Cotton Hull Activated Carbon and Its Effects on Cd(II) Removal from Aqueous Solutions

The novel biosorbent silk cotton hull, an agrowaste material, has been successfully utilized for the removal of cadmium(II) from aqueous solutions. The adsorption of cadmium onto three kinds of activated biosorbent has been studied: modified by concentrated sulfuric acid alone (AC), a mixture of concentrated sulfuric acid and hydrogen peroxide (AC1), and a mixture of concentrated sulfuric acid and ammonium persulfate (AC2). The adsorption studies were carried out to optimize the process parameters such as pH, adsorbent dosage, contact time, and initial metal ion concentration. Maximum metal removal was observed at pH 7.0 with a contact time of 90 min at stirring speed of 200 rpm with an adsorbent dosage of 4.0 g L^?1. The sorption isotherms were studied using the Langmuir, Freundlich, and Tempkin isotherm models. The maximum adsorption capacities were 100.00, 142.86, and 142.87 mg g^?1 for AC, AC1, and AC2, respectively. Accordingly, the surface modification of the activated carbons AC1 and AC2 enhanced cadmium removal greatly. The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. The sorption mechanism is discussed in terms of the activated surface properties. A relationship between the oxygen content and sorption was found in this novel material. Desorption experiments were carried out using hydrochloric acid with a view to generate the spent adsorbent and to recover the adsorbed metal ions.     

籼稻稻米蛋白质含量与外观品质性状间不同遗传体系的条件遗传相关分析

选用稻米蛋白质含量等品质差异较大的7个籼型不育系(A)及相应的保持系(B)与5个籼型恢复系(R)杂交,组成7×5不完全双列杂交组合。应用包括胚乳、细胞质和母体植株基因的遗传主效应以及基因型×环境互作效应的数量性状遗传模型及非条件和条件分析方法,研究了籼稻稻米蛋白质含量与外观品质性状间的遗传相关性,进一步揭示了籼稻糙米重、稻米直链淀粉含量对稻米蛋白质含量与外观品质性状间遗传相关性的影响。非条件分析的结果表明,除了与糙米厚的相关性未达到显著水平以外,蛋白质含量与其它稻米外观品质性状间的遗传相关性均达极显著水平,其中与糙米宽间的相关性表现为正值,其余为负向相关。条件分析的结果显示,糙米重和直链淀粉含量对稻米蛋白质含量与外观品质性状间的遗传相关性均可产生较大的影响。糙米重主要通过基因型×环境互作效应影响蛋白质含量与外观品质性状间的遗传相关性,其中对蛋白质含量与糙米长、糙米宽、糙米厚间遗传相关性的影响主要表现为负向作用,而对蛋白质含量与糙米长宽比、糙米长厚比间遗传相关性的影响则表现为正向作用。稻米直链淀粉主要通过细胞质遗传主效应和母体加性效应影响蛋白质含量与糙米长、糙米长宽比、糙米长厚比间的遗传相关性,而对蛋白质含量与糙米宽间的相关性影响主要表现为负向作用。     

粉碎粒度和不同储藏条件对玉米赖氨酸含量的影响

选择2013年新收获的玉米品种坤臻(糯玉米)、正大999和百农5号,编号为K01、K02和K03,探讨粉碎粒度、储藏温度和储藏时间对不同品种的玉米样品中赖氨酸含量的影响。结果表明:粉碎粒度试验中,K01、K02和K03玉米样品分别经过20目、40目、60目和80目筛处理时,样品过40目或80目筛时赖氨酸含量都相对较高;单因素分析储藏温度(10℃、20℃和30℃)和储藏时间(2、4、6、8个月)对赖氨酸含量的影响时,随着储藏温度的升高和储藏时间的延长,K01、K02和K03样品中赖氨酸含量都有不同程度的下降,其中储藏时间对赖氨酸含量的影响较大,储藏温度次之,储藏8个月时,K01、K02和K03样品中的赖氨酸含量分别下降33.3%、37.1%和39.4%。     

秧宝灵防止早稻烂秧的效应

从化学防寒角度,探讨防止早稻烂秧、培育壮秧的新途径。结果表明,用秧宝灵浸渍早稻种子,不仅有利于增强发芽势,提高发芽率,使种子催成根短芽壮的好秧苗,而且能有效地防止烂秧,达到培育壮秧之目的,并获得早熟增产的良好效果。     

杂交稻核酮糖二磷酸羧化酶的动力学性质

在ｐＨ８．０和３０℃的条件下测定了杂交稻ＲｕＢＰ羧化酶的动力学常数,纯化酶测定值与粗酶快速测定值无明显差异。１２种不同组合的三系杂交稻（Ｆ１）其ＲｕＢＰ羧化酶动力学常数差异不大,Ｋｍ（ＣＯ２）和Ｖｍａｘ的平均值与普通栽培品种也无显著差异。杂交稻汕优６３号ＲｕＢＰ羧化酶的动力学常数和酶蛋白含量与父本恢复系相类似,而母本不育系的Ｖｍａｘ和酶蛋白含量均较高。     

Size and Surface Charge Properties of Myelin Vesicles from Normal and Diseased (Multiple Sclerosis) Brain

Differences have been observed between myelin vesicles prepared from normal human central nervous system and from white matter of patients who died with multiple sclerosis (MS). The mean cross-sectional area of the vesicles was 5.69 +/- 0.17 micron 2 from normal myelin and 3.71 +/- 0.28 micron 2 for diseased myelin. Vesicle size was reduced to 4.08 +/- 0.21 micron 2 when normal myelin vesicles were prepared in the presence of 0.1 mM EDTA. The presence of Ca2+ during the preparation of the vesicles had no effect on the mean cross-sectional area. In the case of MS myelin vesicles, 0.1 mM EDTA had no effect on vesicle size, whereas the presence of Ca2+ increased the vesicle size from 3.71 +/- 0.28 to 5.40 +/- 0.31 micron 2. Electrokinetic analysis revealed that the electrophoretic mobility of normal myelin vesicles was -5.169 +/- 0.193 X 10(-8) compared with -6.093 +/- 0.202 X 10(-8) m2 s-1 V-1 for the MS myelin vesicles. The presence of 0.1 mM EDTA increased the electrophoretic mobility of the normal vesicles to -6.483 +/- 0.151 X 10(-8) m2 s-1 V-1 but did not significantly affect that of the MS vesicles. Addition of 0.1 mM Ca2+ decreased the electrophoretic mobility of both normal and MS vesicles to similar mobilities. From these data, the surface charge densities were calculated for both normal and MS myelin vesicles and found to be -2.93 and -5.39 mV m-1, respectively. The phase transition temperature determined by wide-angle x-ray diffraction studies was 63 degrees C for normal myelin vesicles and 43 degrees C for MS myelin vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of Different Irrigation Management on the Textural Properties of Double-Cropping Late <i>Indica</i> Rice in South China

In order to investigate the effects of different irrigation management on the textural properties of two differentdouble-cropping late Indica rice, the effects of three irrigation management including conventional irrigation(CK), constant irrigation (CI) and alternate wetting and drying (AWD) on textural properties has been researchedunder field conditions of two years. The results indicated that the firmness, cohesiveness and chewiness weredecreased under AWD treatment, and the stickiness was increased compared with CK, while the textural properties under CI treatment showed the opposite trend with AWD treatment. Additionally, AWD treatment signifi-cantly improved the springiness of TY871 compared with CK and CI treatment, but had no significant effect inRYHZ, suggesting improvement of the cooking and eating quality of TY871 under AWD treatment. Correlationanalysis showed that the chewiness was positively correlated with the firmness and cohesiveness, and the cohesiveness was positively correlated with the firmness. AWD could promote the textural properties of high-qualitylate Indica rice in South China whereas CI treatment has shown the disadvantage of the textural properties, whichwill provide useful information for the improvement of cooking and eating quality of rice.     

Effects of Different Potassium (K) Fertilizer Rates on Yield Formation and Lodging of Rice

As one of the most important nutrients for plants, potassium (K) has substantial effects on growth and development of crops. Present study was conducted in three different sites in South China in late season in 2019 with the objective to study the effects of different applied amounts of K fertilizer on yield formation and lodging of rice. Four K fertilizer treatments, K₀: 0 kg potassium oxide (K₂O) ha⁻¹ (control); K₁: 64.20 kg K₂O ha⁻¹ ; K₂: 128.55 kg K₂O ha⁻¹ and K₃ 153.90 kg K₂O ha⁻¹ were applied in the field experiment. The results showed that K₂ and K₃ treatments significantly increased panicle number per unit area, grain number per panicle, seed-setting rate and the grain yield of rice compared with K₀ treatment. Higher net photosynthetic rates were recorded in K₂ and K₃ treatments than K₀ treatment at tillering stage, heading stage and maturity stage. K fertilizer treatments also increased the chlorophyll content and dry matter accumulation by 6.16–23.52% and 21.32–64.59% compared with K₀ treatment, respectively. Moreover, the total N and K accumulation in the aboveground tissues of rice significantly increased under K₂ and K₃ treatments compared with K₀ treatment. Furthermore, compared with K₀ treatment, K fertilizer treatments significantly enhanced the breaking-resistant strength by 40.94–144.24% and reduced the lodging index of rice by 13.14–36.72%.     

Effects of Light Crude Oil Contamination on the Physical and Mechanical Properties of Fine Sand

The use of oil-contaminated sand in building and construction is now being considered as an alternative and cost-effective way to minimize its adverse effect on the environment. To achieve this, the effect of oil contamination on the important mechanical properties of sand should be investigated first. This study investigated the effect of petroleum-derived contaminants on the water absorption, permeability, cohesion, friction angle, and shear strength of fine sand. Contaminated samples were prepared by mixing fine sand with different percentages of light crude oil (0 to 20%). The results indicated that the water absorption of fine sand decreases with an increase in crude oil. An increase in the cohesion was observed for sand with up to 1% of oil contamination, after which the cohesion began to decrease, which also results in the reduction in the permeability. A slight reduction in the friction angle was found for oil-contaminated fine sand. At a low normal stress of 50 kPa, as the percentage of light crude oil increased, the shear strength increased up to 1% of oil contamination and then it decreased. These results provided useful information on how oil-contaminated sand can be used safely and effectively in building and construction.     

蓝光对水稻幼苗生长及内源激素水平的影响

研究表明：与白光对照相比,蓝光明显抑制水稻幼苗的生长,并使幼苗体内的自由态IAA、GA1、玉米素和二氢玉米素含量下降,ABA含量和乙烯释放量则明显增加。说明蓝光对水稻幼苗生长的影响与其体内激素状况有关。     

稀土和锌对黑稻种子发芽的影响

用三个浓度的稀土溶液和硫酸锌溶液对黑稻种子浸种 2 4 h后 ,进行种子的标准发芽试验。 3天后测定种子的发芽势 ,7天后测定发芽率 ,并同期对芽长进行测定。三种浓度的稀土溶液和硫酸锌溶液对黑稻种子的发芽势及同期芽长均有明显促进作用 ,对发芽率则无影响。用硫酸锌溶液浸种应是一种简单易行的补充农田缺锌的方法之一     

The molecular simulation of the miscibility,mechanical properties and physical cross-linking behavior of the poly(vinyl alcohol)/poly(acrylic acid) composited membranes

The miscibility and mechanical properties of poly vinyl alcohol (PVA) and poly acrylic acid (PAA)-composited membranes were studied with molecular simulation. The Flory–Huggins parameters (δ) were calculated to prove the good miscibility of PVA and PAA. The radial distribution functions of hydroxyl and carboxyl atoms and the average number of H-bonds were observed to indicate the degree of physical cross-linking between PVA and PAA. The influences of intermolecular physical cross-linking on the glass transition temperature and mechanical properties were estimated. The results revealed that the PVA/PAA membrane with a composition of 2:3 has the best plastic properties, which exhibits a good application value. All of the simulated results showed good agreement with the experimental data. It indicates that the method presented in this work has a promising application prospect.     

转基因水稻表达的Bt蛋白对拟环纹豹蛛(Pardosa pseudoannulata)生长发育的影响

为明确转基因水稻表达的Bt蛋白沿捕食性食物链的传递及其对生态系统中较高营养级生物的影响,在实验条件下(28±0.5 ℃,R.H=80%,L∶D=12h∶12h)以田间优势自然天敌拟环纹豹蛛为对象,以取食转Cry1Ab/Cry1Ac基因水稻汕优63(简称Bt水稻)叶片24 h的稻纵卷叶螟幼虫为猎物饲养拟环纹豹蛛,并测定了...     

水稻永绿色基因突变和超表达对其叶片类囊体蛋白降解的影响

应用蛋白质免疫杂交技术分析了永绿色基因(Stay-green Rice,SGR)突变和超表达对水稻(Oryza sativa)叶片类囊体蛋白质降解的影响.结果表明,在正常生长条件下,SGR超表达降低了光系统Ⅱ(PSⅡ)、光系统Ⅰ(PS Ⅰ)和电子传递链等的蛋白质含量.暗诱导衰老处理时,SGR突变延缓了PSⅠ和PSⅡ的蛋...     

蜘蛛对稻纵卷叶螟和白背飞虱的选择捕食作用

讨论蜘蛛的主要种群拟水狼蛛、食虫瘤胸蛛、粽管巢蛛对稻纵卷叶螟、白背飞虱的选择捕食特性。由结果可见：猎物被捕食量与参试种群编码值（密度）的数量关系可由二次多项式模型技术。当取每科水稻上有稻纵卷叶螟５头,白背飞虱１０头,拟水狼蛛２头,粽管巢蛛２头,食虫瘤胸蛛２头时,蜘蛛种群对白背飞虱有较大的选择捕食比率。     

Effects of dietary fracture toughness and dental wear on chewing efficiency in geladas (Theropithecus gelada)

Chewing efficiency has been associated with fitness in mammals, yet little is known about the behavioral, ecological, and morphological factors that influence chewing efficiency in wild animals. Although research has established that dental wear and food material properties independently affect chewing efficiency, few studies have addressed the interaction among these factors. We examined chewing efficiency, measured as mean fecal particle size, as a function of seasonal shifts in diet (and corresponding changes in food fracture toughness) in a single breeding population of a grazing primate, the gelada monkey, at Guassa, Ethiopia. We also measured dental topographic traits (slope, angularity, and relief index) and relative two‐ and three‐dimensional shearing crest lengths in a cross‐sectional wear series of gelada molars. Chewing efficiency decreased during the dry season, a pattern corresponding to the consumption of foods with higher fracture toughness. Older individuals experienced the most pronounced decreases in chewing efficiency between seasons, implicating dental wear as a causal factor. This pattern is consistent with our finding that dental topographic metrics and three‐dimensional relative shearing crest lengths were lowest at the last stage of wear. Integrating these lines of behavioral, ecological, and morphological evidence provides some of the first empirical support for the hypothesis that food fracture toughness and dental wear together contribute to chewing efficiency. Geladas have the highest chewing efficiencies measured thus far in primates, and may be analogous to equids in their emphasis on dental design as a means of particle size reduction in the absence of highly specialized digestive physiology. Am J Phys Anthropol 155:17–32, 2014. © 2014 Wiley Periodicals, Inc.