Changes of Terrestrial Water Storage in the Yellow River Basin Under Global Warming

The increasing temperature in the Yellow River Basin has led to a rapid rise in the melting level height,at a rate of 5.98 m yr^(-1)during the cold season,which further contributes to the transition from snowfall to rainfall patterns.Between 1979 and 2020,there has been a decrease in snowfall in the Yellow River Basin at a rate of-3.03 mm dec^(-1),while rainfall has been increasing at a rate of 1.00 mm dec^(-1).Consequently,the snowfall-to-rainfall ratio(SRR)has decreased.Snowfall directly replenishes terrestrial water storage(TWS)in solid form until it melts,while rainfall is rapidly lost through runoff and evaporation,in addition to infiltrating underground or remaining on the surface.Therefore,the decreasing SRR accelerates the depletion of water resources.According to the surface water balance equation,the reduction in precipitation and runoff,along with an increase in evaporation,results in a decrease in TWS during the cold season within the Yellow River Basin.In addition to climate change,human activities,considering the region's dense population and extensive agricultural land,also accelerate the decline of TWS.Notably,irrigation accounts for the largest proportion of water withdrawals in the Yellow River Basin(71.8%)and primarily occurs during the warm season(especially from June to August).The impact of human activities and climate change on the water cycle requires further in-depth research.

Stand structure and height-diameter relationship of a degraded Populus euphratica forest in the lower reaches of the Tarim River, Northwest China

Understanding stand structure and height-diameter relationship of trees provides very useful information to establish appropriate countermeasures for sustainable management of endangered forests. Populus euphratica, a dominant tree species along the Tarim River watershed, plays an irreplaceable role in the sustainable development of regional ecology, economy and society. However, as the result of climate changes and human activities, the natural riparian ecosystems within the whole river basin were degraded enormously, particularly in the lower reaches of the river where about 320 km of the riparian forests were either highly degraded or dead. In this study, we presented one of the main criteria for the assessment of vitality of P. euphrafica forests by estimating the defoliation level, and analyzed forest structure and determined the height-diameter （height means the height of a tree and diameter means the diameter at breast height （DBH） of a tree） relationship of trees in different vitality classes （i.e. healthy, good, medium, senesced, dying, dead and fallen）. Trees classified as healthy and good ac- counted for approximately 40% of all sample trees, while slightly and highly degraded trees took up nearly 60% of total sample trees. The values of TH （tree height） and DBH ranged from 0-19 m and 0-125 cm, respectively. Trees more than 15 m in TH and 60 cm in DBH appeared sporadically. Trees in different vitality classes had different distribution patterns. Healthy trees were mainly composed more of relatively younger trees than of degraded tress. The height-diameter relationships differed greatly among tress in different vitality classes, with the coefficients ranging from 0.1653 to 0.6942. Correlation coefficients of TH and DBH in healthy and good trees were higher than those in trees of other vitality classes. The correlation between TH and DBH decreased with the decline of tree vitality. Our results suggested that it might be able to differentiate degraded P. euphratica trees from healthy trees by determining the height-diameter correlation coefficient, and the coefficient would be a new parameter for detecting degradation and assessing sustainable management of floodplain forests in arid regions. In addition, tree vitality should be taken into account to make an accurate height-diameter model for tree height prediction.

Assessment of tear film parameters post-treatment with commercial eyelid cleaning wipes:a pilot study

AIM:To investigate the short-term effects of commercially available eyelid-cleaning wipes on film parameters.METHODS:This study enrolled 48 healthy participants aged 20-35y(both males and females).Clinical assessment included the Ocular Surface Disease Index(OSDI)questionnaire,non-invasive tear break-up time(NITBUT),tear meniscus height(TMH),and lipid layer pattern(LLP).Based on these initial results,participants were categorized as either non-dry eye or dry eye.Participants in each group were randomly allocated to either Blephaclean■or Systane■treatments.Changes in NITBUT,TMH,and LLP levels before and after lid wipe treatment were assessed.RESULTS:The dry eye group exhibited significantly higher OSDI scores and lower NITBUT and TMH levels than in the non-dry eye group(P<0.001).Following the application of eyelid wipes(Systane■wipes),dry eye subjects experienced a significant improvement in NITBUT levels(P=0.0014)compared to the non-dry eye individuals.Although the remaining participants showed a marginal increase in TMH and NITBUT levels,these changes did not achieve statistical significance(P>0.05).Similarly,the LLP levels were significantly improved with Systane■(P<0.001)post-treatment compared to individuals in the non-dry eye group.However,the dry eye subjects showed higher posttreatment LLP levels than the untreated group(P<0.02).CONCLUSION:The short-term effects of Systane®eyelid wipes on tear film parameters suggest their effectiveness in dry eye disease.Nonetheless,further exploration of their long-term impact is essential to justify their cost effectiveness and efficacy in treating both aqueous deficiency and evaporative dryness.

Intra-and interobserver reliability of ocular surface analyzer LacryDiag

AIM:To invastigate intra-and interobserver reliability of interferometry,tear meniscus height(TMH)measurement and meibography(MBG)of an ocular surface analyzer,LacryDiag(Quantel Medical,France).METHODS:Five consecutive measurements and subsequent analysis of interferometry,TMH,and MBG were recorded by two examiners using the LacryDiag.To assess intra-and interobserver reliability,we used Cohen’s kappa for categorical variables(interferometry),or intraclass correlation coefficient for continuous variables(TMH,MBG).RESULTS:Thirty eyes of 30 examinees were included.For both observers,there was excellent intraobserver reliability for MBG(0.955 and 0.970 for observer 1 and 2,respectively).Intraobserver reliability for observer 1 was substantial for interferometry(0.799),and excellent for TMH(0.863).Reliability for observer 2 was moderate for interferometry(0.535)and fair to good for TMH(0.431).Interobserver reliability was poor for interferometry(0.074)and fair to good for TMH(0.680)and MBG(0.414).CONCLUSION:LacryDiag ocular surface analyzer in our study proves to be a reliable noninvasive tool for the evaluation of TMH and MBG.As for interferometry,poor interobserver reliability,fair to good intraobserver reliability for observer 1,and moderate for observer 2,leave room for improvement.

Correlation of eco-hydrographic benefit and height increment of Robinia pseudoacacia stand with climatic environmental factors in Yellow River Delta Wetland of China

The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.

Vitality variation and population structure of a riparian forest in the lower reaches of the Tarim River,NW China

Since 2000, the Chinese government has implemented emergency water diversion measures to restore the damaged riparian forest ecosystem with dominant tree species Euphrat poplar(Populus euphratica Oliv.)at the lower reaches of the Tarim River. In the present study, comparative analysis of variations in the vitality of P. euphratica trees were made using 2005 and 2010 data to illustrate the revitalization process of riparian forest. Poplar trees within 300 m of the riverbed were positively revitalized, while the vitality of trees farther than 300 m from the river decreased. Population structure was studied to demonstrate the development of poplar community. In the first belt, the class structure for the diameter at breast height(DBH) of P. euphratica fit a logistic model, and the 2nd, 3rd and 4th belt curve fittings were close to a Gaussian model; in other plots they were bimodal. Cluster analysis of the composition of the DBH class of poplar trees demonstrated that those within 16–36 cm DBH were the most abundant(58.49% of total) in study area, under 16 cm of DBH were second(31.36%), and trees >40 cm DBH were the least abundant(10.15%). More than 80% of the trees were young and medium-sized, which means that the poplar forest community in the vicinity of the lower Tarim River is at a stable developmental stage. The abundance of juvenile trees of P. euphratica in the first and second measuring belts was 12.13% in 2005 and increased to 25.52% in 2010, which means that the emergency water transfer had a positive impact on the generation of young P. euphratica trees in the vicinity of the river.

Lipid layer thickness and tear meniscus height measurements for the differential diagnosis of evaporative dry eye subtypes

AIM： To explore a new diagnostic index for differentiating the evaporative dry eye（EDE） subtypes by analysis of their respective clinical characteristics. METHODS： A cross-sectional study of 139 patients（139 eyes） with EDE who were enrolled and classified as obstructive meibomian gland dysfunction（MGD）（n=81） and non-obstructive MGD（n=58） EDE. All patients completed a Standard Patient Evaluation of Eye Dryness（SPEED） questionnaire and were evaluated for average lipid layer thickness（LLT）, tear meniscus height measurements（TMH）, tear break-up time（TBUT）, ocular surface staining score, Schirmer I test（SIT）, lid margin abnormalities, and meibomian gland function and morphology. RESULTS： Age, average LLT, TMH, scores of lid margin abnormalities, meibum quality, meibomian gland loss（MGL）（all P≤0.001）, and TBUT（P=0.03） were all significantly different between obstructive MGD EDE patients and nonobstructive MGD EDE patients. Average LLT in obstructive MGD EDE was correlated with meibomian expressibility（r=-0.541, P≤0.001）, lid margin abnormalities were marginally not significant（r=0.197, P=0.077）, and TMH was correlated with MGL（total MGL： r=0.552, P≤0.001; upper MGL： r=0.438, P≤0.001; lower MGL： r=0.407, P≤0.001）. Average LLT in non-obstructive MGD EDE, was correlated with meibomian expressibility and Oxford staining（r=-0.396, P=0.002; r=-0.461, P≤0.001）. The efficiency of combining average LLT and TMH was optimal, with a sensitivity of 80.2% and a specificity of 74.1%. Obstructive MGD EDE patients had an average LLT≥69 nm and TMH≥0.25 mm, while non-obstructive MGD EDE patients had an average LLT〈69 nm and TMH〈0.25 mm.CONCLUSION： Obstructive MGD EDE and nonobstructive MGD EDE have significantly different clinical characteristics. Combining average LLT and TMH measurements enhanced their reliability for differentiating these two subtypes and provided guidance for offering more precise treatments for EDE subtypes.

三江源地区夏季-10℃层高度变化及云垂直结构特征

利用三江源地区沱沱河、玉树、达日3个探空站的探空资料对1999—2021年-10℃层高度时间变化趋势、突变时间进行了研究,同时对该地区2021年云出现频率和云垂直分布特征进行了研究,并探讨了-10℃层高度、云层垂直结构与降水的关系。结果表明:(1)近20 a来三江源地区夏季08时和20时的-10℃层高度平均值分别为7 014.1、7 201.6 m,并呈显著上升趋势。突变检验分析确定三江源地区夏季08时-10℃层高度出现突变是从2009年开始,20时出现突变是从2012年开始。(2)08时三江源地区夏季云层结构较为复杂,20时三江源地区夏季主要以单层云为主,6—8月平均出现频率分别为35%、42%、39%。从三江源地区夏季云顶高度、云底高度和云层厚度来看,7月云顶高度最低、云底高度最高、云层厚度最小。(3)三江源地区夏季-10℃层位于该地区云层中下部。产生降水时-10℃层高度主要集中在7 200~7 800 m,云层厚度在4 000~11 000 m。三江源地区夏季降水量与-10℃层高度、云顶高、云层厚之间存在显著的正相关,与云底高存在显著的负相关。-10℃层高度与云顶高度、云层厚度间存在显著的正相关;与云底高度间相关性不显著。

河流下多煤层开采安全性及保护技术

我国新疆地区干旱缺水,艾维尔沟河作为新疆一条具有重要地理特征和环境影响的河流,其对于流经区域的经济、生态都具有重要意义,因此在艾维尔沟河下进行煤炭开采时,既要保证矿井安全也要保证河流的正常使用。采用理论分析、数值模拟等方法对河流下多煤层开采安全性及河流保护技术进行研究,通过理论计算得到多煤层开采条件下,覆岩导水裂隙带发育高度(11401工作面为41.9 m、1502工作面为110 m、11401工作面为113.8 m)并绘制剖面示意图;同时,采用数值模拟方法对覆岩导水裂缝发育形态及高度进行确定,最终基于导水裂隙带高度(117.8 m)与最小煤层埋藏深度(191.5 m)的相互关系,确定河流下开采是安全的可行的。在保证河流下煤层安全开采的前提下,通过分析离层注浆原理,并结合采动影响特征参数及工程现场,提出了以离层注浆为主,河道防渗及优化开采设计为辅的多手段对采动影响范围内地表特定目标的精准保护技术。根据实际采矿地质条件,采用概率积分法计算试采工作面开采前后河道位置处地表移动变形,计算结果显示:采用离层注浆精准保护技术后,河道的最大水平变形值(2 mm/m)未超出允许坝体的极限变形值(2.5 mm/m),所以采用离层注浆精准保护技术可以实现,井下安全开采的同时,保证河道的正常使用。通过对河流下多煤层开采的安全性及保护技术的分析研究,为矿山绿色开采提供参考和借鉴。

Simulation and Analysis about the Effects of Geopotential Height Anomaly in Tropical and Subtropical Region on Droughts or Floods in the Yangtze River Valley and North China

Previous study comes to the conclusion： based on the anomalies of the South Asian high （SAH）, 100-hPa geopotential height, and 100-hPa circulation over tropical and subtropical regions, we can predict precipitation anomaly in the Yangtze River Valley and North China. To test its validity, a series of experiments have been designed and operated, which include controlled experiment, sensitivity experiment （which has added anomalies into 100-hPa geopotential height and wind field）, and four-composite experiments. Experiments based on the composed initial field such as EPR-CF, EPR-CD, EPR-HF, and EPR-HD, can reproduce the floods or droughts in the Yangtze River Valley and North China. It suggests that anomalies of the SAH, 100- hPa geopotential height, and circulation over tropical and subtropical regions may probably imply summer precipitation anomalies in the two regions. Sensitivity experiment results show that anomalies of the SAH, 100-hPa geopotential height, and southwest flow in the previous period is a signal of droughts or floods for the following summer in the Yangtze River Valley and North China. And it is also one of the factors that have impact on summer precipitation anomaly in the two regions. Positive anomaly of 100-hPa geopotential height and the anomalous intensifying of the SAH and southwest flow will induce floods in the Yangtze River Valley and droughts in North China; while negative anomaly of 100-hPa geopotential height and anomalous weakening of the SAH and southwest flow will induce droughts in the Yangtze River Valley and floods in North China.

融合星载LiDAR系统GEDI数据与Sentinel-2影像的长江中游洲滩典型禾本科植物高度动态研究

植物是大型河流生态系统的重要成分。但受气候变化和人类活动影响,洲滩禾本科植物高度不断发生调整,进而影响洲滩生境和河道防洪安全,故需长期监测。近年来,伴随着星载激光雷达(LiDAR)技术的发展,应用LiDAR卫星数据反演洲滩禾本科植物高度成为一种可能。本文融合新一代星载LiDAR系统GEDI数据与Sentinel-2影像,基于XGBoost算法构建了考虑物候、累积温度与光合有效辐射指标的洲滩典型禾本科植物高度外推模型,同时利用Attention-UNet算法搭建了洪淹区域识别模型。随后以长江中游洲滩为例,探明了星载LiDAR技术在获取洲滩植株高度方面的性能,分析了各指标对模型精度的影响,并初步得出了洲滩典型禾本科植物高度对不同淹没条件的响应模式。主要结论包括:(1)星载LiDAR系统GEDI具有准确探测洲滩植物高度的能力,与无人机航测数据相比RMSE=0.43 m;(2)运用GEDI数据构建禾本科植物高度外推模型时,考虑物候和累积温度等指标可有效提升模型精度,提升幅度为6.8%~10.7%;(3)利用无人机航测数据对模型外推植物高度进行评价,RMSE=0.80 m。同时从模型外推结果中可知,受2020年流域尺度洪水影响,中游各河段平均植物高度下降了0.03~0.24 m;(4)在2020年流域尺度洪水作用下,淹没历时≤10天的洲滩禾本科植物,其次年株高整体呈增长趋势;而淹没历时>10天时,其次年株高平均下降了2.3%~3.1%。此外,对于日均淹没水深与株高的比值>0.95的洲滩,随着比值增加,洪水对禾本科植株高度的负面作用逐步增强。

人表皮生长因子滴眼液对白内障患者晶状体超声乳化术后干眼症的效果

目的 探讨人表皮生长因子滴眼液对白内障患者晶状体超声乳化术(PHACO)术后干眼症的效果。方法 选取2023年1月至10月安徽省阜阳市人民医院收治的90例白内障PHACO术后干眼症患者为研究对象,按照随机数字表法分成对照组和观察组,各45例。对照组予以聚乙烯醇滴眼液治疗,观察组在对照组基础上加用人表皮生长因子滴眼液治疗。用药4周后,比较两组疗效、泪河高度、泪膜稳定性、视觉质量及不良反应发生情况。结果 观察组疗效优于对照组(P<0.05)。治疗后,两组泪膜破裂时间(BUT)长于治疗前,角膜荧光素染色实验(FL)、眼表疾病指数(OSDI)、标准干眼症状评估量表(SPEED)评分低于治疗前,泪河高度、基础泪液分泌实验(LST)高于治疗前,且观察组BUT长于对照组,FL、OSDI、SPEED评分低于对照组,泪河高度、LST高于对照组(P<0.05)。两组均未见明显不良反应。结论 聚乙烯醇滴眼液联合人表皮生长因子滴眼液用于白内障PHACO术后干眼症患者临床治疗,可通过改善泪河高度及泪膜稳定性,提升效果,并提高患者视觉质量,且用药安全。

NCEP/NOAA全球预报产品在江苏近岸及长江口外的精度评估

利用2021年1—7月江苏近岸和长江口外13个测风站、3个波浪浮标的观测数据,与美国国家环境预报中心/美国国家海洋和大气管理局(NCEP/NOAA)全球预报系统的风场、波浪预报数据进行对比。结果表明:与上一代预报产品相比,目前全球业务预报产品在风场预报方面的准确度明显提高,江苏近岸地区的风速预报误差明显小于长江口外地区,24 h风速和风向预报的均方根误差分别为2 m/s和45°。对大风天、大浪天环境下全球预报产品精度的评估表明:大风天风速预报精度在长江口外降低,在江苏近岸无明显变化,风向预报精度在长江口外无明显变化,在江苏近岸提高;大浪天波高、浪向的预报精度分别降低、提高。在台风极端天气条件下,全球预报产品对长江口的风场仍有一定的预报能力,但预报的最大风速的出现时间滞后6~9 h,且无法预报出风速剧烈变化的情况。尝试基于长短期记忆网络方法利用NCEP/NOAA预报及观测改进业务预报,可以改善短期单站预报水平。

河下采煤“两带”微震监测应用研究

为确定河下煤矿工作面回采后上覆岩层“两带”发育高度范围,采用微震监测技术对工作面回采前后上覆岩“两带”发育过程与高度进行了定性与定量预测,并在此基础上对传统验公式进行修正。结果表明:微震监测方法可以实现顶板“两带”发育高度的有效探测,监测得到的杨村煤矿325工作面顶板最大垮落带与裂缝带高度分别为38.5m与90.01m,满足《三下采煤规范》要求,可以实现河下安全开采。

The response of annual runoff to the height change of the summertime 0℃ level over Xinjiang

According to climate features and river runoff conditions, Xinjiang could be divided into three research areas： The Altay-Tacheng region, the Tianshan Mountain region and the northern slope of the Kunlun Mountains. Utilizing daily observations from 12 sounding stations and the annual runoff dataset from 34 hydrographical stations in Xinjiang for the period 1960-2002, the variance of the summertime 0℃ level height and the changing trends of river runoff are analyzed both qualitatively and quantitatively, through trend contrast of curves processed by a 5-point smoothing procedure and linear correlation. The variance of the summertime 0℃ level height in Xinjiang correlates well with that of the annual river runoff, especially since the early 1990s, but it differs from region to region, with both the average height of the 0℃ level and runoff quantity significantly increasing over time in the Al- tay-Tacheng and Tianshan Mountain regions but decreasing on the northern slope of the Kunlun Mountains. The correlation holds for the whole of Xinjiang as well as the three indi- vidual regions, with a 0.01 significance level. This indicates that in recent years, climate change in Xinjiang has affected not only the surface layer but also the upper levels of the atmosphere, and this raising and lowering of the summertime 0℃ level has a direct impact on the warming and wetting process in Xinjiang and the amount of river runoff. Warming due to climate change increases the height of the 0℃ level, but also speeds up, ice-snow melting in mountain regions, which in turn increases river runoff, leading to a season of plentiful water instead of the more normal low flow period.

Assessments of tear meniscus height, tear film thickness, and corneal epithelial thickness after deep anterior lamellar keratoplasty

Objective： To assess the lower tear meniscus height（LTMH）, central tear film thickness（CTFT）, and central corneal epithelial thickness（CCET） after deep anterior lamellar keratoplasty（DALK）. Methods： This was a retrospective cross-sectional study of 20 patients who had DALK in one eye over a three-month period. LTMH, CTFT, and CCET of the operated eyes and the unoperated fellow eyes were measured using high-definition optical coherence tomography（HD-OCT）. Correlations between three OCT assessments and age, time following surgery, graft size, bed size, and the number of residual sutures were analyzed. Results： Compared to patients with keratoconus, patients with other corneal conditions had significantly higher CCET in the fellow eye（P=0.024）. For all patients, CCET in the operated eye was significantly negatively correlated with the number of residual sutures（R=-0.579, P=0.008）, and was significantly positively correlated with time following surgery（R=0.636, P=0.003）. In the fellow eye, a significant positive correlation was found between age and CCET（R=0.551, P=0.012）, and a significant negative correlation between age and CTFT（R=-0.491, P=0.028）. LTMH was found to be significantly correlated between operated and fellow eyes（R=0.554, P=0.011）. There was no significant correlation between LTMH and age, bed/graft size, time following surgery, or residual sutures（all possible correlations, P0.05）. Conclusions： Patients with keratoconus tend to have a thinner central corneal epithelium. Corneal epithelium keeps regenerating over time after DALK. DALK did not induce a significant change in tear volume compared with the fellow eye. Postoperative tear function might depend on an individual＇s general condition, rather than on age, gender, bed/graft size, time following surgery, or residual sutures.

武汉市GRACE水储量变化与气象干旱关联趋势分析

通过GRACE时变重力异常反演等效水高,对比武汉站的降雨数据,估计武汉市区域水储量变化和气象干旱趋势.研究发现等效水高变化与降雨数据存在相关性,1 a周期吻合,仅相位滞后;在长周期2 a和4 a也有较好的一致性,表现为相位超前,而短周期短相关性较差.GRACE数据提炼的干旱指标GRACE-DSI反映了土壤水、层间水、地表水等陆地水的综合变化;标准化降雨指标SPI则主要反映了降雨和地表干旱情况,两者的结合更全面地反映了气象干旱程度.研究发现GRACE-DSI指标与SPI指标在2002年8月—2020年4月期间的相关性可以分为3个阶段:低相关性、高相关性、再降到低相关性的阶段.特别是在2013年6月—2020年4月,GRACE-DSI指标显示武汉市陆地水储量增加,干旱程度不断缓解,而SPI指标显示该期间多次发生降雨少、地表重度干旱的情况.

卵石地层土压平衡盾构撕裂刀布置模式对比研究

为研究卵石地层土压平衡盾构撕裂刀布置模式对刀具磨损的影响,结合北京地铁19号线平—积区间、牛—金区间基本相同地层条件下撕裂刀不同布置模式的盾构掘进工程案例,采用数学回归分析方法对比“大高差宽间距”和“小高差窄间距”2种撕裂刀布置模式下的刀具磨损系数。研究结果表明:1)在地质情况、掘进参数、渣土改良等条件基本一致的情况下,采取“小高差窄间距”撕裂刀布置模式的刀盘上刀具磨损量更大,其高撕裂刀、低撕裂刀、刮刀的磨损系数分别为“大高差宽间距”模式的1.5、3.2、2倍;2)“大高差宽间距”撕裂刀布置模式下,高、低撕裂刀起到了良好的分层犁松作用,有效降低了撕裂刀的磨损;3)“大高差”撕裂刀布置模式比“小高差”布置模式下的刮刀磨损系数减小了42.7%,“宽间距”布置模式比“窄间距”布置模式下的刮刀磨损系数减小了36.1%。

桂林市会仙岩溶湿地水资源特征及有效调控

会仙湿地是“漓江之肾”,对漓江补水和生态环境改善具有重要作用,但湿地水资源调蓄功能较弱,严重制约了湿地功能的发挥。本研究以会仙湿地为示范区,对湿地核心区狮子岩地下河系统和睦洞湖分散排泄系统流量进行了一个水文年的观测,并实施水资源调控措施。结果表明:会仙湿地岩溶含水层对大气降雨具有一定的调蓄作用,但调蓄功能较弱,雨季后若连续2个月无降雨地下河基本断流;会仙河通过桂柳古运河补给睦洞湖,补水效果取决于会仙河大坝的蓄水高度,当会仙河大坝蓄水高度小于149.25 m时,会仙河无法对湿地进行有效补水,对该大坝重修可增加对睦洞湖湿地的补水效果。针对狮子岩地下河系统具有管道集中径流、流量大、水量充足的特征,在地下河采取了上游“蓄”和“引”,中游“堵”,下游“拦”的三级调控工程使地下河水位从出口到八仙湖段1 km范围内提高70 cm,可缩短狮子岩地下河溶洞湿地低水位期1个月以上。针对睦洞湖分散排泄系统地下水具有分散排泄的特征,采取出口“拦”的水资源调控技术,成功将出口水位抬高30 cm,核心区水位抬高10~20 cm,使睦洞湖湿地低水位期推迟2个月以上。

不同脂质层厚度干眼患者泪膜稳定性的观察研究

目的:探讨不同脂质层厚度条件下泪膜稳定性的差异。方法:纳入2020-06/2021-12于我院就诊的干眼患者194例384眼,应用角膜地形图仪行双眼泪河高度、首次泪膜破裂时间和脂质层厚度测量,分析不同脂质层厚度条件下双眼泪河高度、首次泪膜破裂时间的差异及其相关性。结果:根据脂质层厚度将纳入患者(384眼)分为脂质丰富组(49眼)、脂质平衡组(27眼)、脂质轻微缺乏组(266眼)、脂质显著缺乏组(42眼),四组泪河高度有差异(P=0.022),首次泪膜破裂时间无差异(P=0.322)。脂质层厚度分级与泪河高度呈正相关(r_(s)=0.143,P=0.006),与首次泪膜破裂时间无相关性(r_(s)=-0.090,P=0.083);泪河高度与首次泪膜破裂时间也无相关性(r_(s)=0.038,P=0.460)。结论:泪膜脂质层厚度不同的干眼患者泪膜稳定性无明显差异。