青山湖流域不同地表覆盖降雨径流中氮磷流失过程研究

在浙江省青山湖流域进行了不同地表覆盖类型野外模拟降雨实验,通过设定不同的坡度和降雨强度,综合分析流域内4种地表覆盖对降雨径流中氮磷流失的减少效果,结果表明：在相同雨强情况下,坡地径流中总氮浓度和氨氮浓度由高到低顺序均为：人工草地、次生林、荒草坡、竹林地。其中,总氮浓度曲线在各地表趋势均保持稳定,降雨强度的增大不影响4种覆盖度的顺序结果,但是人工草地与其他3种类型之间的浓度差值会随着雨强的增大而增大。在相同雨强情况下,坡地径流中总磷浓度白高到低顺序依次为：人工草地、次生林、荒草坡、竹林地。径流中速效磷浓度过程趋势与总磷浓度非常类似,而且随着雨强增大,速效磷占总磷比例也相应提高。     

青山湖流域不同地表覆盖降雨径流中氮磷流失过程研究

在浙江省青山湖流域进行了不同地表覆盖类型野外模拟降雨实验,通过设定不同的坡度和降雨强度,综合分析流域内4种地表覆盖对降雨径流中氮磷流失的减少效果,结果表明:在相同雨强情况下,坡地径流中总氮浓度和氨氮浓度由高到低顺序均为:人工草地、次生林、荒草坡、竹林地。其中,总氮浓度曲线在各地表趋势均保持稳定,降雨强度的增大不影响4种覆盖度的顺序结果,但是人工草地与其他3种类型之间的浓度差值会随着雨强的增大而增大。在相同雨强情况下,坡地径流中总磷浓度由高到低顺序依次为:人工草地、次生林、荒草坡、竹林地。径流中速效磷浓度过程趋势与总磷浓度非常类似,而且随着雨强增大,速效磷占总磷比例也相应提高。     

覆盖与行距配置对玉米叶片光合性能和茎秆力学特性及产量的影响

【目的】研究覆盖与行距配置对旱作区春玉米叶片光合性能、茎秆力学特性及产量的影响,为旱作区玉米高产稳产最优种植模式的选择提供理论依据。【方法】以山西省抗旱性强的主推玉米品种大丰30为材料,于2020-2021年采用二因素随机区组设计进行大田试验,以覆盖方式为主区,设无覆盖（T₁,对照）、秸秆覆盖（T₂）、地膜全覆盖（T₃）3个处理,行距为副区,设40 cm+40 cm、40 cm+80 cm、50 cm+50 cm、80 cm+80 cm 4个处理,在不同生育期测定玉米叶片的净光合速率（P_n）和叶绿素含量、茎秆农艺性状、力学特性（茎秆硬皮穿刺强度和抗压强度）及产量。【结果】（1）2020-2021年,随生育时期的推进,不同覆盖和行距配置下玉米叶片P_n均呈现上升趋势,在灌浆期达到峰值,而叶片叶绿素含量逐渐下降。在T₃处理40 cm+80 cm行距配置下,玉米叶片P_n和叶绿素含量最高,平均为26.14 μmol/(m²·s)和5.90 mg/g,其中P_n较T₁(CK)和T₂处理提高19.49%和8.87%,叶绿素含量较T₁(CK)和T₂处理提高16.37%和13.68%。（2）2020-2021年,T₃处理玉米的株高、穗位高和穗位高系数最低,其次为T₂处理,T₁(CK)最高;在T₃处理40 cm+80 cm行距配置下玉米茎秆农艺性状表现优越,不易倒伏。（3）2020-2021年,随节间数的增高,抽雄期玉米茎秆第3~5节的节间直径、茎秆硬皮穿刺强度和抗压强度减小,而节间长度增加。在T₃处理40 cm+80 cm行距配置下玉米茎秆的节间直径最高,茎秆硬皮穿刺强度和抗压强度最大,抗倒伏能力增强。（4）2020-2021年,T₃处理玉米产量最高,T₂处理次之,T₁(CK)最低。在T₃处理40 cm+80 cm行距配置下玉米平均产量为13 616.46 kg/hm²,较T₁(CK)和T₂处理增产10.28%和5.57%,平均倒伏率为1.05%,较T₁(CK)和T₂处理下降8.35%和5.40%。（5）抽雄期玉米的倒伏率与第3节间直径、第3节间硬皮穿刺强度和抗压强度、产量呈极显著负相关,玉米产量与株高、第3节间直径、第3节间硬皮穿刺强度和抗压强度呈极显著正相关。【结论】T₃处理40 cm+80 cm行距配置为最佳模式,适宜在山西省旱作春玉米区大面积推广种植。     

基于改进K-means算法的冬小麦覆盖度提取研究

为快速、精准地提取冬前分蘖期冬小麦覆盖度,提出了一种基于改进K-means算法的冬小麦覆盖度提取方法。首先将冬小麦图像转换到Lab色彩空间,其次利用蜉蝣算法（Mayfly Algorithm, MA）获取K-means最优初始聚类中心,并用马氏距离代替欧氏距离进行算法改进,最后利用分割得到的二值图像计算冬小麦覆盖度。结果显示,该方法的平均分割精度和平均处理时间分别为94.66%和2.03 s,与过绿指数（excess green,EXG）自适应阈值分割和基于粒子群优化算法（particle swarm optimization,PSO）的K-means(PSO-K-means)分割相比,分割精度分别提高了12.04%和4.18%,处理时间分别减少了2.26和2.94 s。该方法分割效果优于EXG和PSO-K-means分割方法,可用于提取冬小麦覆盖度。     

高致病性FAdV-4传代中的毒力和Fiber2基因的比对分析

为筛选禽腺病毒疫苗株和制备亚单位疫苗提供科学依据,探明高致病性禽腺病毒C亚型4血清型（FAdV-4）毒株在传代中的毒力变化以及不同感染方式对雏鸡死亡率的影响,首先制备2 ~ 15代的高致病性FAdV-4尿囊液,用LMH细胞检测第2、4、8和15代尿囊液的半数细胞感染量（TCID₅₀）;其次选取的4个代次尿囊液分别通过黏膜（点眼）和颈背部皮下途径接种SPF雏鸡,观察动物的死亡率;最后应用PCR方法扩增主要结构蛋白Fiber2基因序列并进行比对分析。结果表明：所有制备的2 ~ 15代FAdV-4毒株均在5 ~ 7 d内致鸡胚死亡（100%）,4个代次毒株的TCID₅₀为10^6.5±0.2/0.1 mL,不同代次毒株间的毒力差异不显著（P＞0.05）;选取的4个代次毒株经颈背部皮下接种雏鸡的死亡率为100%,死亡雏鸡出现典型的心包积液综合征。而经黏膜接种的雏鸡死亡率呈下降趋势,分别为80%、50%、30%和30%;不同代次毒株Fiber2基因序列没有发生变化。总之,不同代次毒株通过皮下接种后对雏鸡的致病力没有差异,但黏膜接种的死亡率则逐代下降,而主要结构蛋白Fiber2基因则没有出现碱基变异。     

Spatial disparities in neighborhood public tree coverage: Do modes of transportation matter?

Urban green space has various environmental and ecological benefits, and uneven access to such amenities has drawn substantial attention from policy makers in developing sustainable community planning. In this study, we illustrate the spatial distribution of publicly owned and maintained trees in Edmonton, Canada and assess neighborhoods’ heterogeneous tree availability by using the container approach. Through spatial regression models, we further investigate the association of neighborhood public tree availability with socio-economic status (SES). We contribute to the existing literature by taking resident modes of transportation into consideration, in addition to many other commonly examined SES such as household income and ethnicity. Another unique contribution of this study is that we distinguish trees planted on different location types (i.e., boulevard, park, and buffer areas) when exploring the unequal coverage across neighborhoods and among different SES groups. Key results include: (1) a general examination without differentiating location types can lead to misleading results and thus provide inappropriate policy recommendations; (2) resident modes of transportation is a critical factor associated with a neighborhood’s public tree coverage; and (3) there exists evident spatial dependence on public tree availability between neighborhoods. The results from this study provide important information to better understand the issue and to allocate public resource (such as tree coverage) more efficiently and effectively to support sustainable community development.     

棉花不同基因型品种棉仁含油量及其与纤维品质性状的关系

对41个棉花品种的棉仁油分含量测定表明，不同品种间的棉仁含油量差异较大，平均含油量为31．19%，变幅为27．77%~40．36%，含油量最高的品种为‘中棉所16’，最低的品种为‘豫棉11号’。对41个品种的纤维品质分析结果表明，纤维品质最好的为‘海7124’，最差的为‘晋棉11号’。相关分析表明，棉仁含油量与纤维品质之间无统计学相关性，即可在不降低纤维品质的基础上，开展棉仁高含油量育种研究。     

应用灰色关联度分析棉花的产量与品质

应用灰色关联度、通径分析,研究不同生态环境条件下棉花主要产量性状及纤维品质性状的量化关系。     

Study on the mechanism of microwave modified wheat protein fiber to improve its mechanical properties

Wheat protein is widely used in food industry. In order to expand the scope of its application on non-food field, we managed to apply the wheat protein to fiber production. To improve the mechanical properties of the fibers, we used the method of microwave modification. The best process conditions obtained by response surface analysis were a microwave power of 20.6 W/mL, microwave time of 3 min, and pH 8. Compared to non-microwaved fibers, the breaking strength was 19% higher and the elongation was 302.43% higher which indicated the microwaved fiber toughness was increased. To study the mechanism underlying the effect of microwave treatment on the improvement of mechanical properties, changes in the SH and SS content during wheat protein fiber preparation, a secondary structure study, X-ray diffraction, thermal performance analysis, SEM, surface hydrophobicity, and standard moisture regain measurement were examined. The microwaved fiber had increased SS content, α-helices, crystallinity, which may be responsible for the better mechanical properties. DSC and TG results showed that the thermal stability of microwaved fiber was increased. Additionally, SEM micrographs revealed that the structure of microwaved fibers was smoother and denser, and contained less pores than non-microwaved fibers. Although the surface hydrophobicity and standard moisture regain were decreased, microwaved fiber had good hygroscopicity, which was close to that of silk.     

陇东黄土高原沟壑区水保林有效覆盖率及其确定方法

通过对陇东黄土高原沟壑区水土保持林系统的分析,结合有关水保林科研成果,认为水保林有效覆盖率是指在一定防护范围内土壤流失量等于允许流失量时的林木覆盖率;应用王秋生等人的研究模型计算出陇东黄土高原沟壑区水保林有效覆盖率为43.6%.