辅材参数对酯类香料在卷烟中转移行为的研究

为研究卷烟辅材参数对酯类香料在卷烟中转移行为,采用同时蒸馏萃取及气相色谱仪对酯类香料进行分析,通过改变辅材参数研究酯类香料在烟丝及烟气中分布影响。结果表明,①影响酯类散失率各因素的主次关系为接装纸打孔排数>接装纸打孔个数>成形纸透气度>接装纸打孔距离>接装纸透气度;②影响酯类香料转移率各因素的主次关系为接装纸打孔排数>接装纸透气度>成形纸透气度>接装纸打孔距离>接装纸打孔个数;③综合酯类物质在卷烟中分布情况,接装纸打孔排数2排,接装纸透气度200 CU,接装纸打孔个数8个,成型纸透气度6 000 CU,接装纸打孔距离18 mm,为外加酯类香料卷烟最佳辅材工艺参数。     

黄萎病对棉花叶片SOD、POD酶活性和光合特性的影响

 陆地棉感染黄萎病后，病株叶片的净光合速率较健株叶片下降74.5%；气孔导度、蒸腾速率仅为健株棉叶的46.9%、69.7%；暗呼吸速率比健株棉叶增加6.4%。感病棉株叶片中超氧化物歧化酶、过氧化物酶活性明显比健株减少，分别仅为健株棉叶的88.9%和81.6%，而丙二醛含量比健株棉叶增加47.3%。     

中国稻米品质研究的现状与展望

综述了近年来中国稻米品质研究的现状,详细介绍了关于加工品质、外观品质、蒸煮品质、营养品质以及食味品质等方面的研究成果,并结合自己的研究,提出今后应加强对米饭特性、中间成分和非淀粉成分的研究。     

早熟高产优质特用型绿大豆新品种广石绿大豆1号的选育

对广石绿大豆1号绿大豆新品种的选育经过、品种特征特性及栽培技术做以介绍。     

幼兔饲养管理模式"6,6,6四个不间断"的研究

选用300只35日龄幼兔,研究"6,6,6四个不间断"饲养管理模式对兔生长性能和死亡率的影响。结果表明:采用"6,6,6四个不间断"模式饲养后,兔的生长性能显著或极显著高于其他各组(P<0.05或P<0.01),死亡率极显著低于其他各组(P<0.01)。     

Does habitat restoration cause species extinction?

Habitat destruction is a major cause for species extinction. Does habitat restoration on species evolution with stable state cause species extinction? To address the problem, a multi-species coexistence dynamical model under habitat restoration is set up to simulate the evolutionary trait of different species in different communities. Relevant researches show that habitat restoration has great impacts on landscape changes and species combination. The results find two kinds of latent mechanism of species extinction: the first latent extinction mechanism and the quasi-second latent extinction mechanism. The former refers to the extinction of several vulnerable species while the latter is the extinction of some relatively strongest (not the best) populations. Those survivors experience three phases of transitory increase, adjustment and stability. The dominant species persist and grow fast in different communities, while other several sub-dominant species face the fate of latent crisis of extinction. Two mechanism of n-species community as habitat restorations are found via a number of numerical simulations. One is the mechanism of alternation between oddness and evenness, and the other is the mechanism of coordinate evolution and coordinate degeneration. Two field investigation examples have been given to clarify the evolutionary mechanisms.The results may be helpful for biological conservation and provide theoretical guidance to construct nature reserves.     

Soil C, N and P stoichiometry of Deyeuxia angustifolia and Carex lasiocarpa wetlands in Sanjiang Plain, Northeast China

Purpose

The theory of ecological stoichiometry has improved understanding of nutrient circulation processes in ecosystems. The purpose of this work was to study ecological stoichiometric characteristics of carbon, nitrogen and phosphorus in wetland soils of Sanjiang Plain, northeast China.

Materials and methods

A Deyeuxia angustifolia wetland (swamp meadow) and a Carex lasiocarpa wetland (marsh) were chosen for collection of soil cores (0?C30?cm depth). Soil organic carbon, total nitrogen and phosphorus were analyzed to study patterns of C/N (R _CN), C/P (R _CP), N/P (R _NP), and C/N/P (R _CNP) in wetland soils.

Results and discussion

Soil carbon, nitrogen and phosphorus stoichiometry differed between the two wetlands. Soil R_CN (0?C30?cm depth) in the D. angustifolia wetland was close to that in C. lasiocarpa wetland (12.97 and 12.80, respectively), but R _CP and R _NP in C. lasiocarpa soils were significantly higher than those in D. angustifolia soils. R _CN changed little within soil profile, without obvious trends in both wetlands. Both R _CP and R _NP decreased with depth from the surface, and both R _CP and R _NP were higher at every depth interval in C. lasiocarpa soils compared to D. angustifolia soils. R _CN in surface soil (0?C10?cm, organic-rich ??Lo?? layer) was not significantly different from R _CN in the entire profile (0?C30?cm, ??La layer??) of D. angustifolia wetland, while R _CP and R _NP were both significantly different between the Lo and La layers. In Carex lasiocarpa wetland, R _CN, R _CP and R _NP in Lo layer were significant higher than those in La layer. R _CNP in La layer of D. angustifolia and C. lasiocarpa wetlands were 65:5:1 and 163:13:1, respectively.

Conclusions

Soil R _CN was relatively consistent, while R _CP and R _NP reflected P limitation in wetlands of Sanjiang Plain. Further research is needed to determine whether these ratios hold among other wetland ecosystems.     

辅热集箱式畜禽粪便沼气系统研究

设计了一种新型厌氧发酵系统——辅热集箱式畜禽粪便沼气系统,该系统采用太阳能和生物质辅助加热方式,由若干个集箱式发酵单元组成,可根据养殖规模集装成50、100、200、300、500 m³等不同规模的沼气工程。并在其应用示范工程上完成了运行试验和技术经济评价,结果表明,该系统池容平均产气率为0.80 m³/(m³·d),所产沼气的热值为25.40 MJ/m³,处理后的猪粪污水COD浓度由36500 mg/L降至6500 mg/L,去除率达82.2%,悬浮物浓度由17000 mg/L降至1900 mg/L,去除率达88.8%;其净现值为183530.5元,静态投资回收期为3.58 a。该技术及其成套设备的技术经济可行性较高,具有商业化前景。     

几个新型水稻不育系的育性鉴定

通过分期播种试验,对3个野败型新型水稻不育系华川4A、华J2A、华S40A的生育期、叶龄、柱头外露率、开花习性、农艺性状等进行了观察。结果表明：3个不育系在不育期内的育性稳定,可育期内不育系具有较高的结实率;3个不育系的生育期在60~70d左右,主茎叶片数为13~14片,张颖角度一般在30~40°之间,柱头外露率在39.1%~46.8%左右,花时较为集中,且农艺性状均比较稳定。     

风力作用下沙粒冲击起动风速分析

冲击起动风速是风供给沙粒的能量沙粒与床面碰撞损失的能量正好相等时的风速.文中研究了碰撞过程中入射沙粒动量损失与平坦床面松散沙粒所受冲击力之间的关系,推导沙粒冲击起动风速(Uit)的表达式.对于粗沙(d≥0.1mm),发现U;t与流体起动风速(Uft)的关系可简单地表示成:Uit/Uft=√-yd1/2,其中d为粒径,Y为经验系数.