云南陆良高原水系凤眼莲潜在分布及其影响因素分析

凤眼莲在云南高原水系的分布严重影响陆良县河道工程整治效果。利用最大熵模型MaxEnt和Arc-GIS软件研究河道湿地凤眼莲群落分布,分析影响凤眼莲生长分布的主导环境因子,并解析特征参数对凤眼莲潜在分布和生态位的影响。结果表明:训练集和验证集的AUC值分别为0.965和0.994,模型预测结果良好。凤眼莲主要分布在陆良水系河道中下游,高适生区面积为24.41km2。最暖季降水量,植被保持土壤肥力钾含量、降水量变异系数和海拔对凤眼莲的分布影响较大。研究结果可为云南省陆良县高原区河道湿地的治理提供科学依据。

不同创伤严重程度的多发伤患者血清心肌酶谱指标水平变化及对MODS中心功能障碍的预测价值

目的 探讨不同创伤严重程度的多发伤患者血清心肌酶谱指标[乳酸脱氢酶(lactate dehydrogenase,LDH)、天冬氨酸转氨酶(aspartate aminotransferase,AST)、肌酸激酶同工酶(creatine kinase isoenzyme,CK-MB)、肌酸激酶(creatine kinase,CK)]水平变化及对多器官功能障碍综合征(multiple organ dysfunction syndrome,MODS)中心功能障碍的预测价值。方法 选择多发伤患者67例,根据多发伤患者入院创伤危重评分(injury severity score,ISS)标准将其分为轻度多发伤组(20例)、中度多发伤组(26例)及重度多发伤组(21例);并根据MODS标准,将其分为MODS组及非MODS组。比较创伤后第1、2、3天重度多发伤组、中度多发伤组及轻度多发伤组LDH、AST、CK-MB、CK水平。比较创伤后第1、2、3天MODS组及非MODS组LDH、AST、CK-MB、CK水平比较。采用Spearman秩相关分析LDH、AST、CK-MB、CK与多发伤患者病情严重程度、多发伤患者合并胸腹部位、多发伤患者伴MODS中的心功能障碍的相关性。分析LDH、AST、CK-MB、CK对多发伤患者伴MODS中的心功能障碍的预测价值。结果 重度多发伤组APACHEⅡ评分、MODS例数及MODS评分高于中度多发伤组及轻度多发伤组,中度多发伤组APACHEⅡ评分、MODS例数及MODS评分高于轻度多发伤组(P<0.05)。创伤后第1天、第2天、第3天,重度多发伤组、中度多发伤组、轻度多发伤组LDH、AST、CK-MB、CK水平均呈逐渐降低趋势,重度多发伤组LDH、AST、CK-MB、CK水平均高于中度多发伤组、轻度多发伤组,中度多发伤组LDH、AST、CK-MB、CK水平均高于轻度多发伤组;MODS组和非MODS组LDH、AST、CK-MB、CK水平均呈逐渐降低趋势,MODS组LDH、AST、CK-MB、CK水平均高于非MODS组,组间、时点间、组间·时点间交互作用差异有统计学意义(P<0.05)。采用Spearman秩相关分析结果显示,第1天、第2天、第3天,LDH、AST、CK-MB、CK水平与多发伤患者病情严重程度、多发伤患者合并胸腹部位呈正相关、多发伤患者伴MODS中的心功能障碍均呈正相关(P<0.05)。第1天,多发伤患者伴MODS中的心功能障碍ROC曲线显示,LDH、AST、CK-MB、CK对多发伤患者伴MODS中的心功能障碍有预测价值(P<0.05)。结论 血清心肌酶谱指标水平随多发伤患者病情加重而升高,其与多发伤患者创伤严重程度、胸腹部位及发生MODS中的心功能障碍呈正相关,且是多发伤患者发生MODS中的心功能障碍的危险因素。

2A11粉末激光熔覆影响因素试验研究

采用等离子旋转电极雾化制备2A11粉末,利用激光成型技术熔覆在2A12基体上,研究了不同功率、不同扫描速率对熔覆层熔深、层厚、气孔数量、硬度的影响规律,并提出气孔、裂纹类缺陷的控制方法。结果表明:熔覆功率由800 W递增至950 W,熔覆层的熔深、层厚、气孔数量随之增加,硬度减小;扫描速率由200 mm/min增加至500 mm/min,熔覆层的熔深、层厚随之降低,气孔数量先增加后减少,硬度变化不大。

江苏辐射沙洲海域悬浮泥沙输运分析

根据辐射沙洲邻近主水道和中心沙洲滩面水道33个站点的水深、潮流和水体含沙量同步实测资料,运用悬沙输移机制分解方法,计算了各站位所在水道断面全潮平均单宽悬移质通量、涨潮平均单宽悬移质通量、落潮平均单宽悬移质通量大小及其方向;并对相应悬沙输移的基本路径进行了分析。对各断面潮平均悬沙通量进行了估算,确定了辐射沙洲腹地邻近水道的悬沙净进入断面和净输出断面;辐射沙洲悬沙输移具有以辐射沙洲条子泥滩地为中心的辐聚辐散运移规律;悬浮泥沙净输移在沙洲腹地有逆时针循环运移特征。从东南过来的东海前进潮波潮流携带的泥沙主要沿条渔港水道以及向条子泥腹地输移,并在条子泥沙脊附近与其他方向的来潮来沙相汇,因此条子泥沙滩存在着淤长的动力因素和泥沙条件。

江苏辐射沙洲海域推移质输沙率计算与分析

根据江苏省辐射沙洲潮流水道33个站次连续两个潮次的潮流、底沙实测资料，利用比较分析与拟合研究方法，对各潮流水道的推移质输沙率进行了计算与分析，明确了辐射沙洲主要潮流水道涨潮、落潮、全潮平均推移质单宽输沙率和输运路线；分析得出了1m深流速流向和临底层流速、垂线平均流速有很好的线性关系；拟合构建了江苏省辐射沙洲海域主要潮流水道相应的推移质输沙率流速表达的动力关系式。利用4#~20#站位测量数据及对应计算结果计算拟合得出了西洋水道、豆腐渣腰门水道、陈家坞槽水道的推移质输沙率流速关系式。拟合得出了21#~24#站位所在水道的推移质输沙率计算式，得出了沙洲中心浅滩汊道推移质输沙率关系式;发现推移质输沙率流速表达式在辐射沙洲三个不同区域是有差别。最后利用33个测站的水文测量及计算结果得出了辐射沙洲的整个海域的推移质输沙率计算式。推移质输沙率能用流速很好的表达，一是方便于计算应用，二是可反映内在动力机理。

珠江新造水道河床稳定性数值模拟研究

文章通过MIKE21软件对金光东隧道工程所在河段进行水流泥沙运动模拟。通过对比河床27 h、15 d与45 d的高程变化曲线,发现在通常水动力条件下工程河段河床稳定,没有严重的河床下切,整体上轻微淤积,隧道区域处于轻微淤积状态,施工具有可行性和安全性;随后使用大范围水动力模型输出上游洪、中、枯水三种情况下的边界条件及三种频率设计洪峰流量组合影响下的边界条件,对隧道所在断面进行冲淤对比研究,发现在洪水期隧道断面有明显的冲刷下切现象,下切深度随洪水流量增大而增大,因此在实际施工设计时,隧道埋深要考虑极端洪水作用下的最大冲刷深度。研究结果可为该隧道工程方案设计和施工建设提供一定的参考。

Fluid Mud Measurement and Siltation Analysis in A Trial Excavated Channel in the Approach Channel of the Xiangshan Port

In order to clarify the distribution and variation of silt and fluid mud in the Waiganmen shallow section of the 50000-ton intake channel of the Xiangshan Port,and to understand the influence of the channel excavation on the surrounding flow conditions and the strength of the backsilting,especially the impact of typhoon on the sudden silting of the channel,so as to demonstrate the feasibility and stability of the channel excavation.The fluid mud,hydraulic,sediment and topographic measurements were carried out in the study area,and the thickness of the fluid mud layers,tidal current,sediment and topographic data were obtained.Dual-frequency sounder,gamma-ray densitometer and SILAS navigational fluid mud measurement system were used to monitor the fluid mud,and the results were compared and verified.The adaptability and accuracy of the three methods were analyzed.The SILAS navigational continuous density measurement system and gamma-ray fixed-point fluid mud measurement are used to detect the density,thickness and variation of the fluid mud accurately.Based on the hydrological observation data,the process of erosion and deposition in excavation channel and its influence mechanism are analyzed,and the distribution characteristics and evolution law of siltation in engineering area are given in the form of empirical formula.The research shows that the super typhoon can produce large siltation,which results in sudden siltation of the channel.The tidal current is the main dynamic factor of the change of erosion and siltation of the excavation trench.Under the influence of reciprocating tidal current and excavation topography,the trial excavation trench is silted on the whole.There is fluid mud in the monitoring area of the trench,and the distribution of fluid mud is different in space.The thickness of the fluid mud at the bottom of the trench is generally larger than that outside the trench and the slope of the trench,and the siltation of the trench tends to be slow.The research results can provide scientific evaluation for channel excavation and maintenance,and support for the implementation of the project.

FINE SILT PARTICLE PATHLINE OF DREDGING SEDIMENT IN THE YANGTZE RIVER DEEPWATER NAVIGATION CHANNEL BASED ON EFDC MODEL

Based on the Environmental Fluid Dynamics Code （EFDC）, a three-dimensional baroclinic model for lower reaches of the Yangtze River, Yangtze River Estuary, Hangzhou Bay and the adjacent sea areas was established with the sigma-coordinate in the vertical direction and the orthogonal curvilinear coordinates in the horizontal direction. The fine silt particle tracers were injected during different tides with the calibrated three-dimensional numerical model in the Yangtze River Estuary to simulate the migration tracks of the tracers in the following three days, and thereby study the migration behavior of the fine silt particles of dredged sediment after dumping at different locations in the navigation channel in the Yangtze River Estuary. The study shows that the particle paths of the tracer particles basically migrate to the open sea along the middle axis of river course in the form of reciprocating oscillation, the migration and diffusion directions of tracer particles are basically parallel to the navigation channel in guide levee, similar to long belt distribution, and the tracer particles migrate to the southeast out of the guide levee. The particle which is on the southern and northern sides enter groin and cross the navigation channel in the process of movement, and is easy to deposit in the navigation channel. The migration tracks of the particles released at different layers are basically similar at the same release station, but specifically different, varying at different cross sections. The result can be used for the choice and evaluation of dredging schemes in the Yangtze River Deepwater Navigation Channel.