喀斯特坡地浅层岩溶裂隙土壤团聚体稳定性与养分垂向变化特征

浅层岩溶裂隙（SKF）为植物提供生长空间、水分和养分,是石漠化地区的重要生境类型。以矩形和漏斗形SKF剖面为研究对象,采用干、湿筛分法和Le Bissonnais法,分析了不同土层土壤团聚体稳定性特征和破坏机理,测定了团聚体中土壤有机质（SOM）、碱解氮（AHN）和有效磷（AP）的含量。结果表明：SKF剖面粒径＞0.25 mm的团聚体均超过90%,PAD值范围为0.01%~4.75%。干、湿筛作用下,MWD值变化范围分别为4.63~7.69 mm和1.33~4.24 mm,团聚体分形维数D范围分别为1.57~2.18和1.55~2.15。SKF土壤团聚体的稳定性随剖面深度加深而降低,矩形SKF土壤团聚体的稳定性要强于漏斗形SKF,快速湿润产生的消散作用是造成团聚体破碎的主要机制。团聚体破坏率（PAD）、团聚体分形维数（D）和平均重量直径（MWD）这三类指标均表明,SKF土壤团聚体水稳定性、通透性均较好。SKF剖面30 cm以下土层,团聚体SOM、AHN和AP含量相较0~20 cm土层大幅下降,含量范围分别为13.27±0.94~37.53±3.47 g?kg-1、71.58±3.27~198.54±22.63 mg?kg-1和0.15±0.03~ 0.38±0.10 mg?kg-1,土壤AP十分贫乏。SKF形态会影响SOM含量随土层深度的变化,矩形SKF 30 cm以下土层含量随深度加深而降低,而漏斗形SKF则没有显著性差异。随土层深度加深,矩形和漏斗形SKF剖面AP含量的变化趋势一致,AHN含量的变化趋势则与SKF形态之间没有明显关联。SOM、AHN和AP含量越高,SKF剖面团聚体水稳定性越强。     

基于原型观测与DEM的强风化花岗岩小流域水文过程模拟

为了解华南花岗岩小流域特殊的产流机制,以土壤为砂壤土、基岩为强风化花岗岩的中山大学珠海校区滨海小流域作为研究对象,观测了2个分别代表森林、灌丛覆盖的5 m×10 m的径流试验场的产流过程和土壤含水率变化过程。观测结果表明超渗产流、优先流是试验场的重要产流方式,壤中流（尤其是在土壤-基岩界面上产生的壤中流）对试验场的总产流量也有较大贡献。在径流试验场原型观测基础上,建立了一个基于数字高程模型（DEM）的、包括地表径流、壤中流和基岩裂隙出流的三水源小流域水文模型。利用9次降雨径流过程对模型参数进行率定,利用4次降雨径流过程进行验证,模型的率定、验证均取得了良好的拟合效果。根据模型的模拟结果,在径流的起涨阶段地表产流贡献最大,而基岩裂隙出流对退水过程贡献明显。综合试验场原型观测结果与模型模拟结果得出结论：明显的壤中流和基岩裂隙出流是华南花岗岩小流域显著的产流特点。     

Analysis About The Rules of Buildings Fissure During Repeat Mining

Based on the field data of building fissure and surface horizontal deformation, the author analyzes the building fissure's developing rules during first mining and repeat mining separately, studies the special problem of building fissure's developing rules during repeat mining. From the analysis above, the typical curve between the building fissure's width and surface horizontal deformation during mining is acquired. During mining under the village, if the workface given keeps the same speed, it can ensure the building sustains gradation stretch and compression strain with equality speed, so the residue deformation of building is very small. Conversely, the damage of buildings will be very large. Because the building fissure is liable to occur and develop at spot where the fissure has been already exist, so it is important to maintain the damaged building before repeat mining.     

Occlusal fissures of the equine cheek tooth: Prevalence,location and association with disease in 91 horses referred for dental investigation

Reason for performing study: Fissures of the occlusal surface of the equine cheek tooth are poorly understood and their association with dental disease is unknown. Objective: To describe the prevalence and location of occlusal fissures in the cheek teeth (CT) of a group of horses referred for dental investigation/treatment, and determine association with intercurrent dental disease. Methods: Digital video recordings of oral endoscopic examinations for all horses referred to the Rossdales Equine Hospital for dental investigation from November 2006 to June 2009 were reviewed. Location of occlusal fissures in relation to both Triadan tooth position and pulpar secondary dentine was recorded; direction of fissure and concurrent involvement of enamel was also documented. The CT location considered at the time of examination to be the primary site/s of disease was correlated with presence of fissures on these teeth. Results: 91 cases meeting the inclusion criteria were identified. Occlusal fissures were documented in 58.2% (53/91) cases, with a total of 227 CT being affected. Fissures were most prevalent mid‐arcade. The majority (92.1%) of fissures in maxillary CT were associated with the caudal palatal pulp horn. Fissures in mandibular CT were predominantly associated with the buccal pulp horns (95.7%). There was no significant difference in the median number of CT with fissures in relation to gender. There was no correlation between age (r²= 0.01) of horse and number of CT with fissures. A significantly greater number of CT with multiple occlusal fissures was found in mandibular compared to maxillary arcades. No correlation was found between presence of fissures and location of individual CT considered to be primarily responsible for presentation. Conclusions: Occlusal fissures in this group of animals were common and not correlated to primary site of dental disease. Potential relevance: In horses subjected to dental investigation, occlusal fissures of the cheek teeth should not be considered an indicator of tooth compromise. Location and direction of fissure propagation in most cases is inconsistent with occlusal fissures being causally implicated in slab fractures of cheek teeth, although site predilection may indicate a possible association with masticatory forces.     

山西省太谷县地裂缝的成因分析

太谷地裂缝主要分布在北部平原区。在分析太谷县地裂缝发育特征的基础上,从地质构造、地震、地下水超采和地层等方面,探讨了地裂缝的形成原因。分析得出地层是地裂缝形成的物质基础,基底断裂构造、新构造运动是地裂缝形成的主导原因;地下水的过量开采是地裂缝的关键性诱发因素,并提出了避让、加固、回灌等是防治地裂缝地质灾害的对策。     

磁场对稻谷干燥特性的影响

针对稻谷的传统干燥过程存在能量消耗大，发芽率低和爆腰率高等缺点，把磁场引入稻谷干燥过程中，能快速而经济地降低稻谷的水分并保持其良好品质。采用永磁场强化稻谷的干燥过程，比较干燥时间、发芽率和爆腰率的变化。结果表明：在相同功率下稻谷在磁场中干燥时间比无磁场时缩短5％，平均失水速率加大，稻谷的发芽率有所升高、爆腰率下降；随着干燥功率的增加，磁场对稻谷的发芽率和爆腰率的影响加大。在试验基础上探讨了磁场对稻谷干燥过程的影响机理。     

喀斯特槽谷区岩石与坡面夹角对坡面集中流水力学特性的影响

喀斯特槽谷区地表出露的岩石与坡面形成不同夹角,塑造了复杂的微地貌,显著改变坡面集中水流路径,使得水流特性发生重大变化。目前,不同岩石与坡面夹角下集中流水力学特性的变化特征还不清楚。通过室内放水冲刷模拟试验,研究了3个坡度(10°、15°和20°)、3个冲刷流量(5、7.5、10 L·min-1)和6个岩石与坡面夹角(30°、60°、90°、120°、150°和180°(0°))组合条件下喀斯特槽谷区地表集中流的水力学特性。结果表明:集中水流雷诺数(Re)随冲刷历时变化趋势较复杂,试验条件下,Re随流量的增大而增大,随坡度变化规律不明显,变化范围为517～3343。Darcy-Weisbach阻力系数(f)随冲刷历时表现出增大的变化趋势,其随坡度增大而增大,随流量增大而减小,变化范围为0.62～5.70。Re和岩石与坡面夹角关系均不显著,f和岩石与坡面夹角间的关系在各流量和坡度组合下表现不同。f与Re之间的耦合关系受岩石与坡面夹角的显著影响,当岩石与坡面夹角小于90°时,f-Re关系用对数方程描述比较好;夹角大于等于90°时,则用幂函数方程描述更好。试验条件下,当Re1 791时,f与Re关系不显著;当Re1 791时,f与Re则呈显著正相关。本研究可为喀斯特槽谷区土壤侵蚀预报模型的建立提供依据。     

滇东石漠化坡地浅层裂隙漏失土壤的抗剪强度及其影响因素

[目的] 探讨滇东岩溶断陷盆地植被恢复对改善浅层裂隙土壤理化性质及增强土壤抗剪强度的影响,为减缓土壤漏失,有效遏制该区石漠化态势提供科学参考。[方法] 通过野外调查取样和室内土壤团聚体湿筛、土壤抗剪试验等方法,分析云南松次生林、小铁仔灌丛裂隙土壤基本性质、土壤抗剪性能的垂直变化特征。[结果] ①植被恢复能改善裂隙土壤理化性质,但随着土层深度的变化出现差异。两对比群落裂隙土壤中有机质、砂粒含量、水稳性团聚体（>0.25 mm）随着土层深度的加深呈递减趋势,土壤黏粒含量、水稳性团聚体（<0.25 mm）呈递增趋势;云南松次生林裂隙土壤砂粒（55.46%）、有机质（19.63 g/kg）、水稳性团聚体（76.51%）含量>小铁仔灌丛裂隙（50.16%,11.31 g/kg,67.57%）,粉粒（17.55%）、黏粒（26.99%）、小颗粒团聚体（23.49%）含量<小铁仔灌丛裂隙（22.56%,27.27%,31.43%）。②两对比群落裂隙土壤黏聚力都随着土壤黏粒、水稳性细颗粒团聚体的增多而增大（p<0.05）,土壤内摩擦角随着砂粒、有机质、水稳性大颗粒团聚体的减少而逐渐减小（p<0.05）。③两对比群落裂隙土壤抗剪强度随土层深度的加深而减小,但云南松群落在提升浅层裂隙土壤抗剪性能上要优于灌丛群落,尤其是在中层和深层裂隙土壤,云南松群落抗剪强度大于小铁仔灌丛,两对比群落裂隙的抗剪强度差异性极显著（p<0.01）。[结论] 在滇东断陷盆地石漠化地区,乔林群落更有助于改善中层和深层土壤理化性质,提高土壤抗剪强度,减缓浅层裂隙土壤漏失效应更显著。