Effect of microalloying on wettability and interface characteristics of Zr-based bulk metallic glasses with W substrate

The infiltration casting method is widely employed for the preparation of ex-situ composite materials.However,the production of composite materials using this method must necessitates a comprehensive understanding of the wettability and interface characteristics between the reinforcing phase and the bulk metallic glasses(BMGs).This work optimized the composition of Zr-based BMGs through microalloying methods,resulting in a new set of Zr-based BMGs with excellent glass-forming ability.Wetting experiments between the Zr-based BMGs melts and W substrates were conducted using the traditional sessile drop method,and the interfaces were characterized utilizing a scanning electron microscope(SEM)equipped with energy dispersive X-ray spectroscopy(EDS).The work demonstrates that the microalloying method substantially enhances the wettability of the Zr-based BMGs melt.Additionally,the incorporation of Nb element impedes the formation of W-Zr phases,but the introduction of Nb element does not alter the extent of interdiffusion between the constituent elements of the amorphous matrix and W element,indicating that the influence of Nb element on the diffusion of individual elements is minute.

Effect of Salt Solution on Characteristics of Soil Infiltration

[Objective] The aim was to study the effect of salt solution on characteristics of soil infiltration, and to provide references for the further studies on the effect of water quality on soil infiltration characteristics and its mechanism. [Method] With the NaCl, CaCl2 solutions as the main test materials, the effect of different water quality and salt solution concentration on soil infiltration was studied under one-dimensional vertical ponded water infiltration at laboratory. [Result] The solution concentration could affect the infiltration performance. The trends of the infiltration rates, cumulative infiltrations and wetting front migration distances were all 50 mg/L 100 mg/L 10 mg/L. At the same concentration, the effect of NaCl solution on soil infiltration characteristics was more significant than CaCl2 solution： in the same time, cumulative infiltration and wetting front migration distance of NaCl solution were greater than CaCl2 solution; compared with NaCl solution, CaCl2 solution took longer time to infiltrate the same amount of water. The dynamic changes of infiltration rate, wetting front and cumulative infiltration were well fitted to the Philip model. [Conclusion] This study only conducted indoor experiment to the infiltration of salt solutions, involving in low concentration and small range. Although it provided some references for the study on the effect of water quality on soil infiltration characteristics and its mechanism, studies in larger areas and with bigger concentrations are demanding.

Characteristics of Neutrophils Infiltration in Ventilation-induced Lung Injury

Neutrophils play a critical role in ventilation-induced lung injury. This study was aimed to investigate the characteristics of neutrophils influx in lungs induced by high tidal volume ventilation. Anaesthetized rats were randomly divided into low tidal volume ventilation group (Vt: 7 mL/kg, LV group) or high tidal volume ventilation group (Vt:42mL/kg, HV group ) (n=40 in each). Rats in each group were ventilated for 0, 60, 90, 120 and 240 min. The wet/dry lung weight ratio (W/D) was measured. The levels of macrophage inflammatory protein-2 (MIP-2) and tumor necrosis factor-α (TNF-α), and the activity of myeloperoxidase (MPO) were detected by enzyme-linked immunosorbent assay (ELISA). The number of neutrophils in bronchoalveolar lavage fluid (BALF) was counted after Wright’s staining, and the percentage of netrophils in lung tissues calculated. Histopatholgical examination was used to observe the changes of lung tissues after different ventilations. The results showed that the W/D weight ratio was increased, and the levels of MIP-2 and TNF-α significantly enhanced in HV group at 90, 120 and 240 min. Neutrophils in BALF and the neutrophil percentage in lung tissues were also elevated at 120 and 240 min, which coincided with the enhanced activity of MPO in HV group. The lung injury was significantly related with the ventilation time and the infiltration of neutrophils in lungs in HV group. In conclusion, in ventilation-induced lung injury, neutrophil infiltration is present in a time-dependent manner and associated with the aggravated lung injury. Pulmonary structural damage may be the main reason for ventilation-induced lung injury.

MMP14 is a diagnostic gene of intrahepatic cholangiocarcinoma associated with immune cell infiltration

BACKGROUND Intrahepatic cholangiocarcinoma(ICC)is a malignant tumor of the hepatobiliary system with concealed onset,strong invasiveness and poor prognosis.AIM To explore the disease characteristic genes that may be helpful in the diagnosis of ICC and affect immune cell infiltration.METHODS We downloaded two ICC-related human gene expression profiles from GEO database as the training group(GSE26566 and GSE32958 datasets)for difference analysis,and performed enrichment analysis on differential genes.The least absolute shrinkage and selection operator(LASSO),support vector machinerecursive feature elimination(SVM-RFE)and random forest(RF),three machine learning algorithms,were used to screen the characteristic genes.Double verification was carried out on GSE107943 and The Cancer Genome Atlas,two verification groups.Receiver operating characteristic curve and area under the curve(AUC)were used to evaluate the diagnostic efficacy of genes for ICC.CIBERSORT and ssGSEA algorithms were used to evaluate the effect of characteristic genes on immune infiltration pattern.Human Protein Atlas(HPA)was used to analyze the protein expression level of the target gene.RESULTS A total of 1091 differential genes were obtained in the training group.Enrichment analysis showed that the above genes were mainly enriched in small molecular catabolism,complement and coagulation cascade,bile secretion and other functions and pathways.Twentyfive characteristic genes were screened by LASSO regression,19 by SVM-RFE algorithm,and 30 by RF algorithm.Three algorithms were used in combination to determine the characteristic gene of ICC:MMP14.The verification group confirmed that the genes had a high diagnostic accuracy(AUC values of the training group and the verification group were 0.960,0.999,and 0.977,respectively).Comprehensive analysis of immune infiltration showed that MMP14 could affect the infiltration of monocytes,activated memory CD4 T cells,resting memory CD4 T cells,and other immune cells,and was closely related to the expression of CD200,cytotoxic T-lymphocyteassociated antigen 4,CD14,CD44,and other immune checkpoints.The results of immunohistochemistry in HPA database showed was indeed overexpressed in ICC.CONCLUSION MMP14 can be used as a disease characteristic gene of ICC,and may regulate the distribution of immune-infiltrating cells in the ICC tumor microenvironment,which provides a new method for the determination of ICC diagnostic markers and screening of therapeutic targets.

不同条件下粉碎度及大曲品质研究

制曲原料粉碎后的物料包含大皮、颗粒、细粉三个部分,本实验从钢辊物理特征、使用周期、原料润粮时间等方面探讨其对原料粉碎度影响。实验结果表明,钢辊拉丝角度与深度对物料大皮、颗粒影响较大。随着钢辊使用周期延长,呈现物料大皮偏大、颗粒减少趋势。原料润粮时间以浸润6~9 h为宜。结合季节特性设计粉碎度与水分梯度实验,得出理化指标均衡、感官品质优异的大曲。本实验结果可为中高温制曲生产提供参考。

黑河中游绿洲边缘三种景观类型土壤水分动态特征及影响因素

土壤水分对干旱区旱生植物的生长发育必不可少,决定了旱生植物群落的演替动态和方向。探究黑河中游绿洲边缘不同景观类型的土壤水分动态特征,制定切实有效、科学合理的防风固沙措施,对于阻止荒漠化进程显得尤为重要。本文以黑河中游绿洲边缘的防护林、荒漠-绿洲过渡带和荒漠三种景观类型为研究对象,采用HYDRUS-2D模型模拟、LSD分析法、Pearson相关性分析等方法,研究三种不同景观类型土壤水分动态特征及影响因素。结果表明:(1)土壤体积含水量的RMSE为0.002~0.006 cm^(3)·cm^(-3),MRE为4.22%~5.20%,R^(2)为0.725~0.967,模拟结果与实测数据具有较高的吻合度,HYDRUS-2D模型可用于本研究区土壤水分动态的模拟研究。(2)防护林和荒漠-绿洲过渡带景观的土壤体积含水量随土层深度增加呈现出先增大后减小的变化趋势,荒漠景观则呈现出先减小后增大的变化趋势。(3)有效降水对土壤体积含水量动态变化起决定性作用,9.5 mm以上的降水量可以在短期内显著提高土壤水分含量和入渗深度,荒漠景观降水后的各时段土壤水分入渗深度高于防护林景观和荒漠-绿洲过渡带景观。(4)三种景观类型的土壤体积含水量与降水、蒸散发、容重、土壤颗粒组成、土壤持水性能等因素有关,且表现出不同程度的显著相关(P<0.01),其中,降水、黏粉粒含量与土壤体积含水量呈显著正相关,容重、砂粒含量与土壤体积含水量呈显著负相关性。因此,研究区栽植防风固沙灌木可以增加土壤黏粉粒含量,提高土壤收集利用雨水的能力,减缓入渗作用的进程,从而对土壤持水性能产生积极影响。

食管鳞癌中Versican、NF-κB和MMP-9的表达及其与临床病理特征的关系

目的:观察食管鳞癌组织中多功能蛋白聚糖(Versican)、核因子-κB(Nuclear factor-kappa B,NF-κB)和基质金属蛋白酶-9(Matrix metalloproteinase-9,MMP-9)蛋白及mRNA的表达及其与临床病理特征的关系。方法:采用免疫组化及原位杂交方法检测47例食管鳞癌组织及癌旁正常食管黏膜组织中Versican、NF-κB和MMP-9蛋白及mRNA的表达情况,并分析其与临床病理特征的关系及三者的相关性。结果:食管鳞癌组织中Versican、NFκB和MMP-9蛋白及mRNA表达的阳性率均明显高于癌旁正常食管黏膜组织中的表达(P<0.05);食管鳞癌组织中Versican、NF-κB和MMP-9蛋白及mRNA的高表达与浸润深度越深、淋巴结有转移、TNM分期越晚均有关(P<0.05),与性别、年龄、组织分级均无关;食管鳞癌组织中,Versican、NF-κB和MMP-9三者在蛋白及mRNA水平的表达均呈正相关(P<0.05)。结论:Versican、NF-κB和MMP-9在食管鳞癌中的高表达与肿瘤的生成、浸润及转移密切相关,并且三者具有相关性,为我们进一步探索食管鳞癌浸润转移的潜在机制奠定了基础。

基于生物信息学分析探索普通登革热特征基因及免疫浸润特点

目的:探究普通登革热的特征基因及免疫浸润特点。方法:基于GEO数据库中的GSE96656、GSE206829芯片与R软件,分析普通登革热患者与健康者之间的差异表达基因。利用随机森林模型以及LASSO回归模型筛选疾病特征基因,并通过外部数据集验证基因表达情况。采用CIBERSORT算法进行普通登革热的免疫浸润分析,并分析特征基因与免疫细胞浸润的相关性。结果:共获得500个差异表达基因。随机森林模型以及LASSO回归模型筛选出IFI44L、FMO4作为疾病特征基因。外部数据集验证发现IFI44L在普通登革热患者全血中呈高表达。IFI44L与M1巨噬细胞、活化的树突状细胞和记忆性B细胞的浸润程度呈正相关;FMO4与M1巨噬细胞、活化的记忆性CD4^(+)T细胞的浸润程度呈正相关(P<0.05)。结论:IFI44L、FMO4可能是普通登革热的特征基因,且与免疫细胞如M1巨噬细胞浸润有关。

磁化微咸水对南疆盐渍土壤水分入渗及盐分淋出特征的影响

为探究磁化微咸水灌溉对南疆盐渍土入渗及盐分离子迁移特征的影响,采用恒定磁场强度400 mT对矿化度分别为0、2、3、5 g/L微咸水进行磁化处理,以未磁化处理为对照,对比分析各处理累积入渗量、湿润锋运移距离和淋洗后不同土壤剖面总盐、脱盐率、盐分离子和SAR的影响规律。结果表明:磁化微咸水入渗减小了相同时间内的累积入渗量和湿润锋深度,降低了Philip入渗模型吸渗率,土壤含水率比未磁化微咸水提高5.00%~6.29%;磁化处理显著降低了土壤含盐量,对0~50 cm土壤内总盐含量磁化处理较未磁化降低11.79%~41.64%,在同一磁化强度下,土壤含盐量随矿化度的增加而增加,脱盐率随矿化度的增加而降低。在同一矿化度下,磁化处理含盐量低于未磁化处理,脱盐率高于未磁化处理。磁化微咸水灌溉有利于降低土壤中盐分离子含量,0~50 cm土层K^(+)、Na^(+)、Ca^(2+)、Mg^(2+)、HCO_(3)^(-)、Cl^(-)、SO_(4)^(2-)含量磁化较未磁化处理降低16.90%~25.97%、43.62%~64.68%、11.15%~31.44%、-8.12%~49.07%、-74.14%~13.43%、21.46%~52.81%、6.66%~13.10%。磁化微咸水灌溉处理显著降低0~50 cm土层深度处土壤SAR。

B7-H6在宫颈上皮内瘤变、宫颈癌组织中表达差异及与肿瘤浸润T淋巴细胞、预后的相关性

目的探究宫颈上皮内瘤变、宫颈癌组织中B7同源体6(B7-H6)表达差异与肿瘤浸润T淋巴细胞、预后相关性。方法选取2019年6月—2021年3月60例经病理检查确诊为宫颈癌的手术患者作为研究组,另选同期同年龄段60例宫颈上皮内瘤变作为对照组。比较2组组织B7-H6表达情况(H-score评分)及血清B7-H6水平,并比较研究组不同肿瘤浸润T淋巴细胞浸润程度患者H-score评分、血清B7-H6水平,分析研究组H-score评分、血清B7-H6水平与肿瘤浸润T淋巴细胞浸润程度的相关性。研究组术后随访1年,比较不同预后患者一般资料、H-score评分、血清B7-H6水平,探讨预后影响因素,并分析H-score评分和血清B7-H6水平预测患者预后的价值。结果研究组H-score评分和血清B7-H6水平高于对照组(P<0.01)。研究组肿瘤浸润T淋巴细胞浸润程度0级患者H-score评分、血清B7-H6水平高于1级、2级患者,且1级患者高于2级患者(P<0.05)。研究组H-score评分、血清B7-H6水平与肿瘤浸润T淋巴细胞浸润程度呈负相关(P<0.01)。多因素Logistic回归分析显示,肿瘤直径、国际妇产科协会(FIGO)分期、淋巴结转移、间质浸润深度、H-score评分、血清B7-H6水平均为宫颈癌手术患者预后不良的独立危险因素(P<0.01)。肿瘤直径、FIGO分期、淋巴结转移、间质浸润深度、H-score评分和血清B7-H6水平预测宫颈癌手术患者预后不良的曲线下面积(AUC)分别为0.736、0.726、0.714、0.712、0.842和0.840,H-score评分和血清B7-H6水平预测的AUC分别大于肿瘤直径、FIGO分期、淋巴结转移、间质浸润深度预测的AUC(P<0.05)。H-score评分和血清B7-H6水平在预测宫颈癌手术患者预后不良方面拥有良好的临床效用。结论宫颈癌组织B7-H6表达高于宫颈上皮内瘤变,且宫颈癌组织B7-H6表达、血清B7-H6水平与肿瘤浸润T淋巴细胞浸润程度呈负相关,也是宫颈癌手术患者预后不良的独立危险因素,在预测预后方面具有一定临床价值。

膜孔灌自由入渗条件下VG模型参数的敏感性分析

【目的】探究膜孔灌自由入渗条件下VG模型参数敏感性。【方法】基于HYDRUS-2D软件,采用单因子扰动分析方法,研究van Genuchten方程中α、n、θr对膜孔灌单点源自由入渗特性的影响。【结果】①单位膜孔面积累积入渗量与α负相关,与n正相关,θr对单位膜孔面积累积入渗量无影响。水平湿润锋运移距离与α负相关,θr对其无影响。垂直湿润锋运移距离与θr负相关,与n正相关。入渗结束时高含水率湿润体面积与θr、n正相关,n的扰动对高含水率湿润体面积影响最大。②单位膜孔面积累积入渗量的相对灵敏度随α增大而逐渐减小,α的正扰动对单位膜孔面积累积入渗量的影响程度弱于负扰动。α负扰动时,水平湿润锋运移距离的相对灵敏度随扰动幅度的增大而逐渐增大;α正扰动时,水平湿润锋运移距离的相对灵敏度随扰动幅度的增大而逐渐减小。③n负扰动时,单位膜孔面积累积入渗量与垂直湿润锋运移距离的相对灵敏度均随扰动幅度的增大呈先增加后减小的趋势;n正扰动时,单位膜孔面积累积入渗量的相对灵敏度随扰动幅度的增大呈先减小后增加再减小的趋势。【结论】n发生扰动对膜孔灌自由入渗特性影响最明显,θr发生扰动对入渗特性影响最小。

多因素影响下膜孔灌单向交汇入渗特性

为研究膜孔直径、膜孔间距、土壤初始体积含水率、入渗水头4个因素对膜孔灌单向交汇入渗特性的影响,通过室内土箱入渗试验资料来验证HYDRUS-3D模拟膜孔灌单向交汇入渗过程的可靠性,用HYDRUS-3D模拟不同膜孔直径、膜孔间距、土壤初始体积含水率、入渗水头条件下的单向交汇入渗过程,分析各因素耦合条件下单向交汇入渗规律,分别建立了各影响因素与单位膜孔面积累积入渗量、交汇时间、交汇面面积之间的经验模型.结果表明:4个因素对单位膜孔面积累积入渗量的影响程度从大到小依次为膜孔直径、土壤初始体积含水率、膜孔间距、入渗水头;对膜孔交汇入渗交汇发生时间的影响程度从大到小依次为膜孔间距、膜孔直径、土壤初始体积含水率、入渗水头;对入渗结束时交汇面湿润体面积的影响程度从大到小依次为膜孔直径、膜孔间距、土壤初始体积含水率、入渗水头.该研究结果可为确定最优膜孔灌技术要素组合提供理论依据.

不同含水率下分散土冻融变形及渗透特性试验研究

分散性黏土具有遇水分散的特征,对水利工程的堤坝、道路工程的路基产生很大的危害.总结失事工程的教训同时,深入研究分散性黏土,弄清其影响渗透破坏的因素并采取适当的措施,能够有效防止事故发生.为解决分散土冻融作用后的承载能力下降问题,采用冻融和土体渗透试验研究不同含水率下分散土冻胀、融沉性能,并分析冻融循环次数对冻胀、融沉的影响作用,不同温度条件下分散土的变形特性,以及分散土的渗透性能及其影响因素,为科学指导分散性土的应用提供支撑.研究结果表明:当采用分散性土筑堤时,土体含水率适宜控制在小于最优含水率,冻胀性相对较弱;随着冻融循环次数的增加,分散性土的冻胀率和融沉系数呈先减小再增加的变化,土体的残余变形随着冻融次数增加而降低;分散性土体在一定干密度下试验水头变化相对值随时间的增长逐渐增大,渗透系数随时间增长逐渐减小.

Identification of marker genes associated with N6-methyladenosine and autophagy in ulcerative colitis

BACKGROUND Both N6-methyladenosine(m6A)methylation and autophagy are considered relevant to the pathogenesis of ulcerative colitis(UC).However,a systematic exploration of the role of the com-bination of m6A methylation and autophagy in UC remains to be performed.AIM To elucidate the autophagy-related genes of m6A with a diagnostic value for UC.METHODS The correlation between m6A-related genes and autophagy-related genes(ARGs)was analyzed.Finally,gene set enrichment analysis(GSEA)was performed on the characteristic genes.Additionally,the expression levels of four characteristic genes were verified in dextran sulfate sodium(DSS)-induced colitis in mice.RESULTS GSEA indicated that BAG3,P4HB and TP53INP2 were involved in the inflammatory response and TNF-αsignalling via nuclear factor kappa-B.Furthermore,polymerase chain reaction results showed significantly higher mRNA levels of BAG3 and P4HB and lower mRNA levels of FMR1 and TP53INP2 in the DSS group compared to the control group.CONCLUSION This study identified four m6A-ARGs that predict the occurrence of UC,thus providing a scientific reference for further studies on the pathogenesis of UC.

底水气藏开发对策研究现状

底水气藏在我国天然气勘探开发中占有重要地位,但底水气藏之间构造及储层物性差异大,气水关系复杂,水侵方式难以预测,导致常规开发对策适应性差,严重影响底水气藏开发效果。为此,广泛调研国内外底水气藏开发实例,对比不同底水气藏的地质构造特征差异,分析水侵方式与开发效果,总结不同储渗类型的底水气藏在不同开发阶段适宜的开发对策。研究结果表明:①碳酸盐岩底水气藏常见裂缝发育,储层以裂缝-孔隙型与缝洞型为主,碎屑岩底水气藏常见局部微裂缝发育,储层以孔隙型居多。②不同储渗类型的底水气藏在水侵方式上具有较大的差异性,针对目标气藏应采取适合于该气藏特征的开发对策。③底水气藏在不同的开发阶段都有特定治水目标,早期阶段通过优化开发技术政策参数与优选完井方式延长无水采气期,中期阶段通过单井排水、堵水以及阻水等措施缓解局部气井出水,晚期阶段以恢复动用地质储量与水淹井复产为目标选择开发对策。该研究成果为底水气藏的开发提供借鉴与参考。

不同原材料生物炭基渗融尿素肥的养分迁移转化机制研究

【目的】研究对比不同原材料生物炭基渗融尿素肥(Biochar-based infiltrated urea fertilizer,BIUF)的成肥及养分释放特性,探讨渗融法制肥中生物质种类、热解温度、表面官能团含量对肥料颗粒释放机制的影响,为BIUF缓释性能的进一步优化提供理论指导。【方法】以稻壳炭(Husk biochar,HB)、松子壳炭(Pine nut biochar,PNB)、油茶壳炭(Oil-tea biochar,OTB)、花生壳炭(Peanut biochar,PB)和尿素颗粒为原料,采用渗融法制备BIUF,利用万能压力试验机、扫描电子显微镜、热重分析仪和傅里叶红外光谱仪对其成型特性和养分迁移机制进行研究。【结果】生物炭颗粒的表观形貌及孔壁厚度影响BIUF的物理性能,与易碎薄片化的生物炭颗粒相比,蜂窝状的生物炭颗粒结构更利于提高BIUF的物理机械性能,抗破碎性能提升1.7~2.3倍。生物炭表面的官能团含量影响BIUF的缓释性能,炭表面的—COOH、—C=O和—OH等官能团与尿素生成稳固的化学态尿素,而链式脂肪醇上的—OH与尿素发生醇解反应,造成BIUF肥力下降,释放周期缩短40%~50%。蜂窝状的稻壳炭孔隙结构复杂、含氧官能团丰富以及链式脂肪醇含量低,所制备的花生壳炭基渗融尿素肥具备优异的抗破碎性能,养分释放周期延长90%以上,具备良好的释放性能。【结论】不同生物炭独特的理化性质具备良好的养分吸附性,通过提高热解温度、延长热解时间可提升生物质材料的炭化程度,所制备的BIUF具备优异的物理性能以及一定的缓释性能,对农业的可持续发展具有积极影响。

桶型基础负压沉贯阻力及渗流场特性研究

【目的】在桶型基础的安装过程中,施加的负压不仅会给桶基提供向下的驱动力,与此同时负压还会使沉贯的过程中产生由外而内的渗流场,外部海水自桶外绕过端部之后向桶内渗流。为了探究和评估在该渗流场的作用下,周围土壤有效应力发生的变化,以及对桶基内外壁的摩擦力及端部承载力变化的影响,对均质海床和成层海床的沉贯阻力展开研究。【方法】应用有限元软件COMSOL Multiphysics,采用数值模拟的方法,分别建立饱和砂土、黏土以及成层土桶型基础沉贯安装过程中的二维轴对称模型,探究评估在渗流场作用下沉贯阻力的变化情况。【结果】结果显示:渗流场对桶型基础在砂土海床中的沉贯产生了明显的减阻效应,施加负压后沉贯总阻力降低超30%,而对黏土海床的影响较小,均质海床中的渗流场分布具有相似的特性。对于上砂下黏海床,由于黏土层对渗流的抑制,导致沉贯阻力较均质砂土增大20%,上黏下砂海床由于黏土层对负压的削弱,导致沉贯阻力较均质黏土增大36%。【结论】结果表明:施加的负压一方面为桶基提供了竖向力,另一方面减小了沉贯阻力。而成层海床情况比单一砂土、黏土海床更加复杂,在土壤条件分界处各渗流要素发生突变,较易引起桶基内部土壤的破坏。研究成果可对现场安装施工提供更加方便和有效的理论性指导。

基于低场核磁共振技术PVC-P土工膜细观渗透机理研究

PVC-P土工膜的防渗性能是膜防渗结构乃至工程安全运行的关键。为避免传统上用渗透系数表征其渗透性能的弊端,运用多组渗透压力下土工膜垂直渗透试验数据和基于低场核磁共振技术获取的孔隙度,构建了渗透流量-孔隙度数学模型,结合孔隙和孔径动态分布探讨了用孔隙度评价其垂直渗透性能的适用性。结果表明:以1H原子为探针的低场核磁共振技术能够准确量测膜内孔隙和孔径分布;依据T2特征谱弛豫时间划分的微孔隙、中孔隙和大孔隙的占比以及孔隙范围内孔径的萎缩或发育是孔隙度变化的根本原因;孔隙度与渗透流量关联性较强,利用量测的饱和PVC-P土工膜孔隙度和构建的模型能够准确预测渗透流量。研究成果表明基于低场核磁共振技术测得的孔隙度可用于PVC-P土工膜防渗性能评价。

喀斯特槽谷区不同土地利用方式下土壤入渗特征及适宜模型

[目的]探究喀斯特槽谷区不同土地利用方式下土壤入渗规律,提出适合喀斯特槽谷区的土壤入渗模型。[方法]以喀斯特槽谷区4种典型土地利用类型(林地、草地、耕地、园地)为研究对象,分析不同土地利用类型土壤入渗特征差异及影响因素,评价了Horton,Kostiakov和Philip这3种常见入渗模型在该区的适应性。[结果](1)不同土地利用类型土壤容重、含水率和电导率存在显著差异(p<0.05),耕地土壤容重(1.1 g/cm^(3))、含水率(26.9%)以及电导率(75.43 mS/cm)低于其他土地利用类型,园地土壤容重(1.32 g/cm^(3))、林地含水率(35.02%)以及草地电导率(164.6 mS/cm)分别高于其他土地利用类型。(2)不同土地利用类型土壤入渗过程均表现为迅速下降、缓慢下降以及趋于稳定。(3)Horton模型、Kostiakov模型和Philip模型对喀斯特槽谷区不同土地利用方式拟合结果存在差异,其中,Horton模型结果最优,拟合度R 2达到0.922~0.951,Philip模型拟合结果最差,拟合度R 2为0.754~0.908。(4)pH值与初始入渗速率和平均入渗速率呈极显著正相关关系(p<0.01),与稳定入渗速率呈显著正相关关系(p<0.05);0.05~0.25 mm和<0.05 mm微团聚体分别与稳定入渗率和平均入渗率呈显著正相关和负相关(p<0.05)。多元线性回归模型表明,容重、含水率以及<0.05 mm微团聚体是主要影响入渗速率的因子,且与入渗性能指标存在负相关关系。[结论]不同土地利用方式下耕地具有更好的渗透性能,Horton模型更适合模拟喀斯特槽谷区土壤入渗,研究结果可为喀斯特槽谷区土壤入渗性能评估及植被配置等提供科学依据。