共查询到20条相似文献，搜索用时 31 毫秒
1.
Böcker U Ofstad R Bertram HC Egelandsdal B Kohler A 《Journal of agricultural and food chemistry》2006,54(18):6733-6740
FT-IR microspectroscopy and light microscopy were used to investigate pork muscle musculus semitendinosus samples, taken from three animals, that were subjected to brine salting at different concentrations (0.9, 3, 6, and 9% NaCl). Differences in spectral characteristics and in microstructure were observed in meat from animals differing in initial pH and varying salt concentrations. The FT-IR data displayed changes in the amide I region from 1700 to 1600 cm(-1). This spectral range was analyzed by principal component analysis (PCA) and partial least-squares regression (PLSR). These methods revealed correlations between the spectral data and the different animals, salt content, moisture content, pH value, and myofiber diameter. A shrinking share of alpha-helical components was related to an increase in salt concentration in the muscle. At the same time, a greater share in nonhydrogenated C=O groups (1668 cm(-1)) was related to an increase in salt concentration in the meat. The share of aggregated beta-strands differed with respect to the different animals but was not influenced by salt concentration. The meat at higher pHs (>6) had less aggregated beta-strands than that at lower pHs (5.6-5.7). It could be demonstrated that simultaneous with changes in microstructure, pH value, salt, and moisture content were alterations in the protein amide I region as measured by FT-IR microspectroscopy, revealing a relationship between these biophysical and chemical parameters and secondary protein structure attributes. 相似文献
2.
Aursand IG Gallart-Jornet L Erikson U Axelson DE Rustad T 《Journal of agricultural and food chemistry》2008,56(15):6252-6260
Low-field (LF) (1)H NMR T 2 relaxation measurements were used to study changes in water distribution in lean (Atlantic cod) and fatty (Atlantic salmon) fish during salting in 15% NaCl and 25% NaCl brines. The NMR data were treated by PCA, continuous distribution analysis, and biexponential fitting and compared with physicochemical data. Two main water pools were observed in unsalted fish, T 21, with relaxation times in the range 20-100 ms, and T 22, with relaxation times in the range 100-300 ms. Pronounced changes in T 2 relaxation data were observed during salting, revealing changes in the water properties. Salting in 15% brine lead to a shift toward longer relaxation times, reflecting increased water mobility, whereas, salting in saturated brines had the opposite effect. Water mobility changes were observed earlier in the salting process for cod compared to salmon. Good linear correlations ( F 相似文献
3.
Wu Z Bertram HC Kohler A Böcker U Ofstad R Andersen HJ 《Journal of agricultural and food chemistry》2006,54(22):8589-8597
Fourier transform infrared (FT-IR) microspectroscopy and low-field (LF) proton NMR transverse relaxation measurements were used to study the changes in protein secondary structure and water distribution as a consequence of aging (1 day and 14 days) followed by salting (3%, 6%, and 9% NaCl) and cooking (65 degrees C). An enhanced water uptake and increased proton NMR relaxation times after salting were observed in aged meat (14 days) compared with nonaged meat (1 day). FT-IR bands revealed that salting induced an increase in native beta-sheet structure while aging triggered an increase in native alpha-helical structure before cooking, which could explain the effects of aging and salting on water distribution and water uptake. Moreover, the decrease in T2 relaxation times and loss of water upon cooking were attributed to an increase in aggregated beta-sheet structures and a simultaneous decrease in native protein structures. Finally, aging increased the cooking loss and subsequently decreased the final yield, which corresponded to a further decrease in T2 relaxation times in aged meat upon cooking. However, salting weakened the effect of aging on the final yield, which is consistent with the increased T2 relaxation times upon salting for aged meat after cooking and the weaker effect of aging on protein secondary structural changes for samples treated with high salt concentration. The present study reveals that changes in water distribution during aging, salting, and cooking are not only due to the accepted causal connection, i.e., proteolytic degradation of myofibrillar structures, change in electrostatic repulsion, and dissolution and denaturation of proteins, but also dynamic changes in specific protein secondary structures. 相似文献
4.
为研究脯氨酸及KCl对海鲈鱼品质的影响,本试验用不同腌制组分(NaCl、NaCl+脯氨酸、NaCl+KCl、NaCl+KCl+脯氨酸)在4℃条件下干腌海鲈鱼,分别在腌制18 h、腌制36 h(结束)、风干3 h、风干6 h取样,测定海鲈鱼的pH值、色差、水分含量、含盐量、硫代巴比妥酸(TBA)值,同时进行质构、微观结构和感官评价。结果表明,随着处理时间的延长,不同处理腌制海鲈鱼pH值均呈现先下降后上升的趋势,含水量始终呈下降趋势,而含盐量则呈现上升趋势,用NaCl+脯氨酸腌制海鲈鱼后测得的TBA值最低,为1.415 7mg·kg-1。通过透射电镜观察,添加脯氨酸使鱼肉组织更紧密,能更好地溶解肌球蛋白。使用NaCl+KCl+脯氨酸的减盐配方结合干腌法对海鲈鱼进行腌制,制得的海鲈鱼硬度和咀嚼性较高,并且能够有效抑制脂肪氧化,使肌球蛋白更好的凝集,得到风味及品质更好的产品。本研究结果为海鲈鱼的工业化腌制生产提供了技术支撑。 相似文献
5.
Al-Saghir S Thurner K Wagner KH Frisch G Luf W Razzazi-Fazeli E Elmadfa I 《Journal of agricultural and food chemistry》2004,52(16):5290-5296
Salmon fillets were steamed, or pan-fried without oil, with olive oil, with corn oil, or with partially hydrogenated plant oil. The exchange between the salmon and the pan-frying oils was marginal, but it was detectable as slight modifications in the fatty acid pattern and the tocopherol contents according to the oil used. Primary and secondary oxidation products were only slightly increased or remained unchanged, which indicated a slight lipid oxidation effect due to the heating procedures applied. The same was observed for tocopherol levels, which remained almost stable and were not affected by the oxidation process. The sum of cholesterol oxidation products (COPs) increased after the heating processes from 0.9 microg/g in the raw sample to 6.0, 4.0, 4.4, 3.3, and 9.9 microg/g extracted fat in pan-fried without oil, with olive oil, corn oil, partially hydrogenated plant oil, and steamed, respectively. A highly significant correlation was found between the fatty acid pattern and the total amount of COPs (r2 = 0.973, p < 0.001). No change has been determined in the n-3 fatty acids content and in the polyunsaturated/saturated-ratio of the cooked salmon fillets. Moderate pan-frying (6 min total) and steaming (12 min) of salmon did not accelerate lipid oxidation but significantly increased the content of COPs. The highest increase of COPs was found through steaming, mainly due to the longer heat exposure. The used frying oils did not influence the outcome; no significant difference between heat treatment with or without oil has been determined. 相似文献
6.
含盐量是衡量咸鸭蛋品质的重要指标。为了利用机器视觉技术实现高压脉动腌制咸鸭蛋含盐量的无损检测。该研究采用工业相机和透射光源搭建咸鸭蛋的透射图像采集装置。采用图像整体特征和长轴截面光强度特征两种特征提取方法,利用多元线性回归、支持向量机回归两种算法,建立对蛋清、蛋黄及全蛋含盐量以及蛋黄指数的定量预测模型。结果表明,随着咸鸭蛋腌制时间的增加,其透光性显著提高。同时,透射图像蛋黄的所在视野区域会随着含盐量的增加而呈现规律性的变化。基于图像整体特征建立的蛋清、蛋黄、全蛋含盐量模型较优,在蛋黄指数预测下基于长轴截面光强度特征所建模型较优。其中,基于图像整体特征所建立的蛋黄含盐量支持向量机回归（support vector regression, SVR）模型最优,测试集相关系数（test set correlation coefficient, Rp）、测试集均方根误差(root mean square error of prediction, RMSEp)、相对分析误差（residual predictive deviation, RPD）分别达到0.8460、0.3416、1.898;基于长轴截面光强度特征建立的蛋黄指数多元线性回归（multiple linear regression, MLR）模型最优,测试集相关系数Rp、均方根误差RMSEp、相对分析误差RPD分别为0.8318、0.0743、1.916。该研究结果为咸鸭蛋含盐量的快速检测提供理论依据和技术支持。 相似文献
7.
为探索不同解冻方式对猪肉饼品质和蛋白质氧化程度的影响,本试验将-18℃冻藏的调理猪肉饼分别采用室温解冻、冷藏解冻、流水解冻以及盐水解冻4种方式进行解冻,通过测定解冻后肉饼的保水性(解冻损失率、离心损失率)、pH值、TBARS值、TVB-N值,并测定猪肉饼肌原纤维蛋白羰基含量、巯基含量、蛋白溶解等,分析不同解冻方式对其蛋白氧化程度的影响。结果表明,解冻对调理猪肉饼保水性有较大影响,其中空气解冻与冷藏解冻组的保水性最好,解冻损失维持在5.03%~5.75%之间,离心损失率在31.02%~32.19%之间;同时与新鲜肉饼组相比,空气解冻、盐水解冻和流水解冻组猪肉饼TVB-N值显著上升(P<0.05),盐水解冻组TVB-N值上升至3.17 mg·100g-1;但解冻对调理肉饼pH值、TBARS值、色泽的影响均不显著(P>0.05);通过对肌原纤维蛋白氧化程度的测定发现,解冻会引起肌原纤维蛋白羰基含量上升、巯基含量和溶解度下降,SDS-PAGE试验也证明解冻会引起蛋白质发生不同程度的降解。本研究为实际生产中冻结肉制品解冻工艺的选择与优化提供了一定的理论依据。 相似文献
8.
该文通过对盐渍过程海鳗肌肉中的食盐、水分、质量和密度的变化来研究氯化钠扩散动力学和热力学，以期了解海鳗盐渍过程的基本机制。结果表明，鱼体体积变化与水分失去，水分失去与食盐获得之间具有良好的线性关系，相关系数分别为0.998和0.994。水分失去和食盐获得随着时间变化的拟合相关系数都为0.992，其平均相对误差分别为4.62%和4.87%，动力学模型能很好地与实验数据相吻合。动力学预示的鱼体体积、水分和食盐含量变化，可作为确定腌制时间的依据。热力学研究表明，盐的扩散系数是温度和初始盐渍浓度的函数,活化能的大小表示了温度对扩散过程的影响，活化能随着初始盐渍浓度增加而减小。当鱼体盐浓度较小时，温度是加速腌制的重要因素。 相似文献
9.
该研究以新鲜蛋黄为原料,利用快速腌制模具,探究在咸蛋黄的上表面添加食盐单侧腌制过程中,食盐添加量和腌制时间对咸鸡蛋黄快速腌制过程中形貌特征和理化性质变化规律的影响。借助多种仪器分析手段对蛋黄腌制过程中形貌与物性的变化、水分及盐分的迁移规律进行了表征。低场核磁及成像结果表明：在腌制过程中,蛋黄中的水分不断向外迁移,含水率显著降低,当增加食盐的添加量和延长腌制时间,会加快水分的迁移速率;原子吸收结果表明：增加食盐添加盐量越多和腌制时间越长盐分迁移速率越快,质构、色差结果共同表明咸蛋黄腌制过程中,由于水分的向外迁移和盐分的向内渗入,使得蛋黄的蛋白质发生聚集使颜色加深;同时与市售整个腌制后分离的鸡蛋黄产品相比,当腌制时间为7d,添加盐量为3%;腌制时间为3d,添加盐量为5%时,所得的样品与市面的成品咸鸡蛋黄的感官品质及量化指标差异不显著（P<0.05）,为咸蛋黄单侧腌制技术提供理论的可行性。 相似文献
10.
复合抗氧化剂浸渍处理提升冻藏罗非鱼片品质 总被引：2，自引：0，他引：2
为了提高罗非鱼片的冻藏稳定性,以硫代巴比妥酸值(thiobarbituric acid,TBA)、Ca2+-ATPase活性、盐溶性蛋白含量、挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量及质构等为试验指标,进行了维生素E、异抗坏血酸钠及茶多酚等抗氧化剂溶液浸渍处理对冻藏罗非鱼片品质影响的单因素试验,并在单因素试验的基础上进行抗氧化剂复配的正交优化试验。获得了不同的抗氧化剂浸渍浓度对冻藏罗非鱼片品质的影响规律,以主观赋权法对TBA值、Ca2+-ATPase活性、盐溶性蛋白含量、TVB-N和质构(硬度和弹性)5个指标分别赋权后计算各指标的综合评分,确定了各抗氧化剂的较佳浸渍浓度及最佳复合抗氧化剂的组合配方。结果表明,维生素E溶液和异抗坏血酸钠溶液的较佳质量浓度均为6 g/L,茶多酚溶液的较佳质量浓度为4 g/L,在较佳质量浓度条件下各品质指标综合评分与蒸馏水浸泡60 min的对照组相比分别提高了29.11%,18.46%和46.28%。参照成本分析与较优品质结合优化组合的复合抗氧化剂的配方为:异抗坏血酸钠质量浓度为4 g/L、维生素E为质量浓度2 g/L和茶多酚质量浓度为3 g/L,经此配方处理后的冻藏罗非鱼片对应的品质指标分别为TBA值0.1248 mg/kg,Ca2+-ATPase活性3.12μmol/(mg·h),盐溶性蛋白质量分数为77.72 mg/g,均优于单一抗氧化剂的作用,与蒸馏水浸泡60 min的对照组相比,各指标提升幅度为:Ca2+-ATPase活性提高52.20%,盐溶性蛋白质量分数提高16.78%,TBA值下降46.07%。研究结果为复合抗氧化剂的开发及其在冻藏水产品中的应用提供参考。 相似文献
11.
Perisic N Afseth NK Ofstad R Kohler A 《Journal of agricultural and food chemistry》2011,59(18):10052-10061
The objective of this study was to investigate the influence of NaCl and two salt substitutes, MgSO4 and KCl, in different concentrations (1.5, 6.0, and 9.0%) on meat proteins by using Fourier transform infrared (FTIR) microspectroscopy. Hydration properties and secondary structural properties of proteins were investigated by studying the amide I, amide II, and water regions (3500-3000 cm(-1)) in FTIR spectra. By applying multivariate analysis (PCA and PLSR), differences between samples according to salt concentration and salt type were found and correlated to spectral bands. The most distinctive differences related to salt type were obtained by using the water region. It was found that samples salted with MgSO4 exhibited hydration and subsequent denaturation of proteins at lower concentrations than those salted with NaCl. Samples salted with KCl brines showed less denaturation even at the 9.0% concentration. The FTIR results were further supported by water-binding capacity (WBC) measurements. 相似文献
12.
Aidos I van der Padt A Luten JB Boom RM 《Journal of agricultural and food chemistry》2002,50(16):4589-4599
Crude and fatty acid composition analyses were performed on fillets, byproducts, and oil originating from herring (Clupea harengus) caught off the North Sea from June 1999 to January 2001. Monthly statistical differences were found in the fat content, the range of variation being larger in fillets than in byproducts. The most consistent change observed in fillets was an increase of unsaturation from May to September reflected in a reduced percentage of monounsaturated fatty acids, whereas for byproducts and oil this trend was not so well defined. The results indicated that the lowest values of the total amount of polyunsaturated fatty acids (PUFAs) in the oil were found from January to March (approximately 14%), coinciding with the postspawning and starvation period. In contrast, the highest values were found from June to August (approximately 23%). Thus, the herring byproducts are all year an adequate raw material for fish oil production; however, during the summer they are richer in PUFAs. 相似文献
13.
应用可见/近红外高光谱成像测定鲑鱼片脂肪含量分布(英文) 总被引：1，自引：1，他引：0
脂肪作为一种重要的品质参数,在大西洋鲑鱼片中的分布很不均匀。为寻找一种能替代脂肪化学检测的快速无损的方法,该研究应用可见/近红外高光谱成像测定大西洋鲑鱼片的脂肪含量分布。分别采用可见/短波近红外(400-1100 nm)和近红外(900-1700 nm)系统获取大西洋鲑鱼片样本的高光谱图像。提取样本图像的平均光谱并与其相应的脂肪含量化学值采用偏最小二乘回归(partial least squares regression,PLSR)和最小二乘支持向量机(least-squares support vector machines,LS-SVM)建立相关性模型。为降低高光谱图像的共线性和冗余度,基于竞争性自适应重加权算法(competitive adaptive reweighted sampling,CARS)分别在可见/短波近红外和近红外光谱区间提取16个(468,479,728,734,785,822,863,890,895,899,920,978,1005,1033,1040,1051 nm)和15个(975,995,1023,1047,1095,1124,1167,1210,1273,1316,1354,1368,1575,1632,1661 nm)特征波长,并分别建立PLSR和LS-SVM模型。特征波长模型的性能优于全波段模型,且近红外区间的特征波长PLSR模型为最优,预测决定系数(R2p)为0.92,预测均方根误差(root mean square error of prediction,RMSEP)为0.92%,剩余预测偏差(residual predictive deviation,RPD)为3.50。最后,将最优模型用于预测高光谱图像上所有像素点的脂肪含量以展示样本上脂肪的分布。此外,还基于该技术对大西洋鲑整鱼片实现了脂肪分布可视化。结果表明高光谱成像技术结合化学计量学方法在大西洋鲑鱼片脂肪的定量和分布可视化上有一定的研究和应用前景。 相似文献
14.
蒸发脱湿过程中盐胁迫对苜蓿生长及矿质元素吸收运输的影响 总被引：8，自引：0，他引：8
用土壤溶液浓度ＮａＣｌ７５ ～３２５ ｍｍｏｌ／Ｌ的中性盐对苜蓿 进行胁迫处理，研究苜蓿在土壤脱湿过程中，盐胁迫对其生长及矿质元素吸收运输的影响． 结果表明，ＮａＣｌ胁迫浓度的增加和胁迫时间的延长均使苜蓿的相对生长速率、含水量、累积 蒸散量、水分利用效率、Ｋ含量和Ｋ／Ｎａ值下降，但土体中的剩余水量却呈上升趋势．苜蓿生长 受到水分与盐分胁迫双重胁迫的影响．随ＮａＣｌ胁迫的增加，苜蓿的Ｎ素含有率变化不大，但积 累量显著减少；Ｋ＋、Ｃａ２＋的比吸收率（ＳＡＲ）显著降低，植株Ｋ＋、Ｃａ２＋含 量减少，而植株Ｎａ＋、Ｃｌ－的比吸收率ＳＡＲ显著提高，牧草体内Ｎａ＋、Ｃｌ－含量不断积 累增加，植株Ｋ／Ｎａ值降低．对Ｐ、Ｍｇ２＋的吸收在不同水盐条件下变化不一致．苜蓿根系 吸收钾钠离子后，向茎叶运输钾的选择性随ＮａＣｌ胁迫的不同而呈现出不同的趋势． 相似文献
15.
[目的]探讨欧洲鹅耳枥(Carpinus betulus)对盐胁迫的响应及其耐盐性。[方法]以两年生欧洲鹅耳枥幼苗为材料,用不同浓度NaCl(0%,0.1%,0.2%,0.3%,0.4%,0.5%)溶液处理幼苗,研究不同盐分胁迫对其幼苗生长及生理生化指标的影响。[结果](1)随着盐胁迫的加剧,欧洲鹅耳枥幼苗受到损害程度逐渐加重,相对苗高生长、相对地径生长和总干重均呈下降趋势,而根冠比则逐渐增大;(2)叶片相对含水量随着盐胁迫程度的增加而下降,且盐浓度越高,时间越久,变化幅度越大;(3)叶片叶绿素总量、SOD活性、POD活性、可溶性糖含量和可溶性蛋白含量随着盐胁迫程度的增加表现出先升高后降低的趋势;(4)随着盐浓度的增加和盐害时间的持续,幼苗叶片MDA含量、相对电导率和脯氨酸含量总体上呈增大趋势,并在胁迫末期达到最大值。[结论]欧洲鹅耳枥幼苗在0.1%~0.2%盐胁迫下能通过调节保护酶活性和渗透调节物质来减轻危害;而在0.3%胁迫下,幼苗自我调节能力受影响,0.4%~0.5%胁迫对其造成严重的损害,表明欧洲鹅耳枥耐盐性较弱,不宜在滨海地区生长。 相似文献
16.
壳聚糖对NaCl胁迫下菜用大豆结瘤固氮的影响 总被引：1，自引：0，他引：1
【目的】研究壳聚糖对盐胁迫抑制菜用大豆结瘤固氮的缓解效应,为进一步探讨壳聚糖抗逆机理提供新的线索。【方法】以蛭石为基质,以菜用大豆‘特早王’–根瘤菌共生体系为研究对象,采用人工气候箱培养,研究NaCl胁迫下壳聚糖对菜用大豆根瘤形成、生物固氮的影响。菌种为与‘特早王’共生匹配性较好的快生根瘤菌N18。接种后的植株进行如下4个处理:1)叶面喷施清水,根部浇灌无氮营养液(CK);2)叶面喷施壳聚糖水溶液,根部浇灌无氮营养液(CTS);3)叶面喷施清水,根部浇灌溶有NaCl的无氮营养液(Cl);4)叶面喷施壳聚糖水溶液,根部浇灌溶有NaCl的无氮营养液(CTS+Cl)。上述各处理施用的水或水溶液均为无菌水配制,NaCl处理的浓度为50 mol/L,CTS处理的适宜浓度为200 mg/L。接种30天后,将大豆植株取出,用清水将根部蛭石冲洗干净后,立即测定根瘤固氮酶活性、根瘤数及根瘤鲜重,然后测定根瘤豆血红蛋白含量和根系活力,最后测植株干重和全氮量。【结果】氯化钠胁迫下,植株干重显著下降,与CK相比降幅达49%,喷施壳聚糖后(CTS+Cl),降低幅度显著减小,但依然显著低于CK (P <0.05)。无盐条件下,与CK相比,壳聚糖处理(CTS)增加植株干重的效果不明显。喷施壳聚糖显著增加了菜用大豆的根瘤数、根瘤鲜重、植株含氮量、根系活力、豆血红蛋白含量及固氮酶活性(P <0.05)。NaCl胁迫显著抑制了菜用大豆的结瘤固氮作用,其中根瘤数、根瘤鲜重分别较CK下降了79%、90%,而壳聚糖处理(CTS+Cl)使菜用大豆在盐逆境下的结瘤数、根瘤鲜重、植株全氮含量、根系活力、豆血红蛋白含量及固氮酶活性等均显著回升,增幅分别达对照的29%、20%、17%、48%、19%、21%,但均显著低于CK。【结论】非NaCl胁迫下,喷施壳聚糖可以显著促进菜用大豆结瘤,提高豆血红蛋白含量及固氮酶活性,最终增加植株含氮量。在NaCl胁迫下,外源壳聚糖可以显著缓解氯化钠胁迫导致的对根系活力和结瘤固氮的影响。因此,叶面喷施壳聚糖是促进菜用大豆结瘤固氮和生长的有效措施。 相似文献
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为了实现对芥菜的快速腌渍,采用磁场和流动盐液相结合的方式对样品进行处理,并与静置条件下的腌渍进行了对比。利用不同磁感应强度的磁场(200、1 000、2 000 Gs)和流速场(0.03、0.06、0.22 m/s)完成对芥菜的腌渍处理,同时考察了传质动力学方程。结果表明:当腌渍条件于磁感应强度2 000 Gs和流速0.06 m/s时,可在180 min时间内使样品表层盐分达到饱和,盐分扩散系数为k=2.35×10-2 min-1,而当腌渍液处于湍流(0.22 m/s,雷诺数Re=4 132)的情况下则不利于盐分扩散,只施加磁场的静置腌渍对传质无显著提高(P0.05),而当腌渍液在层流状态下(雷诺数Re=563和1 127)则有利于盐分向多孔状原料的渗透,最佳工艺参数为磁感应强度B=2 000 Gs和流速v=0.06 m/s且该条件下的传质动力学模型可采用Logistic方程进行描述,预测方程决定系数为R2=0.976,该研究为农产品快速浸渍加工提供了参考。 相似文献
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土壤盐结皮能够抑制水分蒸发，减少地表粉尘释放，在干旱区生态环境中具有十分重要的作用。为了获得干旱或半干旱区风沙土盐结皮的合理盐溶度，选取新疆塔克拉玛干沙漠东部风沙土为实验土壤，分别加入0.1%、0.2%、0.5%、1.0%、2.0%、3.0%、4.0%、5.0%、6.0%和7.0%（盐占混合物的百分比）的NaCl进行盐结皮实验，测试盐结皮的强度和韧性。利用电镜观察盐结皮微观结构，分析NaCl盐溶度对结皮抗压强度以及其抗风蚀性能的影响。实验结果表明：NaCl含量对风沙土结皮抗压强度和韧性有较大影响，随着NaCl含量的增加盐结皮的强度和韧性均呈现出先增加后降低的特殊现象；但盐结皮的抗压强度峰值和韧性峰值不同步，NaCl含量3.0%时，盐结皮韧性达到峰值；NaCl含量4.0%时，盐结皮的抗压强度才达到峰值。盐结皮表观和微观结构显示，盐含量>4.0%后结皮盐晶体出现盐斑聚集，这种盐晶体聚集导致盐结皮不均匀，进而导致盐结皮抗压强度复杂变化。 相似文献
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冻融状态和初始含水率对土壤力学性能的影响 总被引：4，自引：2，他引：2
冻融状态影响土壤的抗剪强度从而威胁季节性冻土地区的工程安全、边坡稳定以及土壤流失。通过直剪试验测定了不同冻融状态和初始含水率对青藏地区(S1)和北京地区(S2)土体抗剪强度的影响。结果显示,2种土在未冻和已融状态下的抗剪强度相似,且均随着土含水率的增加而减小,但S1土抗剪强度比S2土大7.5%~9.7%;在冻融状态下,S1土抗剪强度随着土含水率的增加而增大,而S2土则随之减小。S1冻融土抗剪强度在低含水率(≤13.5%)时小于未冻土和已融土,而在高含水率(≥24.5%)时则反之;S2冻融土抗剪强度小于未冻土和已融土。在冻融状态下2种测试土的内摩擦角显著小于未冻土和已融土,而黏聚力整体上则大于未冻土和已融土。与未冻土或已融土相比,2种土在冻融状态下的强度相对较低,宜作为季节性冻土地区工程设计以及土壤流失防治的基本状态。 相似文献