聚L-乳酸改性麦草共混物材料的研究

以聚L-乳酸(PLLA)和麦草(WS)为原料,以N-甲基吗啉-N-氧化物(NMMO)为溶剂,采用溶液共混法制备了PLLA/WS共混物。首先将麦草溶解在NMMO后,再添加聚L-乳酸并溶解,制备聚L-乳酸与麦草的共混溶液。共混溶液采用浇膜法制备PLLA/WS共混物,采用差示扫描量热法、X射线衍射法、傅里叶变换红外光谱、热重分析和扫描电镜等方法对所得的共混物进行表征。结果表明,聚L-乳酸与麦草可以形成均匀的共混溶液。共混物中PLLA与麦草组分之间具有较强的相互作用,相容性较好。当共混物中PLLA的质量分数为50%时,共混物可以形成结晶结构,且随着PLLA含量的增加,其结晶更加完美,熔点与热稳定性提高。共混物薄膜断面结构较为致密,这说明PLLA与麦草相容性较好,混合均匀。通过调节聚L-乳酸和麦草的配比,可以制备不同性能的生物高分子材料。     

城乡绿道的游憩功能实现及产品开发

在乡村旅游发展过程中,以生态休闲为特色的绿道应当作为乡村旅游规划的元素之一。文中简述目前绿道建设存在的误区,提出适宜城市居民游憩的绿道选择,并对城乡绿道的游憩功能实现途径进行探讨,对基于绿道建设的旅游开发进行展望。     

Calculation Method of Hydraulic Characteristics for Direct-Return Chilled Water System

In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence.     

用Nested-PCR检测广西黄皮与九里香黄龙病病原

摘要：运用nested-PCR技术对广西黄皮和九里香进行柑桔黄龙病（Citrus Huanglongbing, HLB）检测,结果表明：从部分黄皮和九里香样品抽提的DNA中,可扩增出一条特异性的400 bp条带,说明广西种植的黄皮和九里香均可感染黄龙病;在柑桔黄龙病疫区,黄皮和九里香黄龙病感染率分别为35.0%和40.0%。     

Shock-induced localized amorphization in boron carbide

High-resolution electron microscope observations of shock-loaded boron carbide have revealed the formation of nanoscale intragranular amorphous bands that occur parallel to specific crystallographic planes and contiguously with apparent cleaved fracture surfaces. This damage mechanism explains the measured, but not previously understood, decrease in the ballistic performance of boron carbide at high impact rates and pressures. The formation of these amorphous bands is also an example of how shock loading can result in the synthesis of novel structures and materials with substantially altered properties.     

“家风”追踪发现命案嫌疑人尸体

2008年9月14日上午9时许,广东省高州市宝光街道朝培桐村发生一起凶杀案,茂名市茂南区村民沈某在中秋节时前往朝培桐村岳母莫某家,劝说因争吵而赌气回娘家的妻子程某回家,但遭到妻子和岳母的反对。一气之下,沈某持菜刀将77岁的岳母莫某杀死,将妻子程某及出租车司机砍致重伤,     

空气污染对蜜蜂及蜜粉源植物的影响探究

近年来,蜜蜂失踪现象多发引起全球蜂业从业者关注,其归因众说纷纭。有认为是农作物滥施农药或频繁在蜂群中使用杀螨药物导致;有解释为移动、电信基站电磁干扰蜜蜂飞行所致;也有说是气候异常引起;等等。笔者以几十年亲身观察本地蜂群的群势变化与实践证明,推测蜜蜂失踪现象另有其因。在此呈现,供同行们从另一个角度探究愈演愈烈的蜜蜂失踪之谜。     

猪繁殖与呼吸综合征病毒实验感染SPF猪外周血单核细胞和肺泡巨噬细胞早期凋亡细胞的观察

采用Ａｎｎｅｘｉｎ Ｖ－ＦＩＴＣ／ＰＩ双染色法,用流式细胞仪检测了猪繁殖与呼吸综合征病毒（ＰＲＲＳＶ）实验感染ＳＰＦ猪不同时期外周血单核细胞和肺泡巨噬细胞感染Ａｎｎｅｘｉｎ Ｖ－ＦＩＴＣ＾＋／ＰＩ＾－细胞群（早期凋亡细胞群）。结果显示,ＰＲＲＳＶ感染猪外周血单核细胞和肺泡巨噬细胞Ａｎｎｅｘｉｎ Ｖ－ＦＩＴＣ＾＋／ＰＩ＾－细胞群的表达率均明显高于正常对照猪,感染后２４ｈ表达率达最高值。     

家蚕种茧育稚蚕人工饲料育的比较试验

通过对日系种茧育稚蚕人工饲料育繁育的一代杂交种进行比较试验。探讨人工饲料在种茧育上的应用可能性。