Geochronology,geochemistry and Hf isotope of monzogranite in Niubiziliang of Qinghai

Zircon U-Pb dating, whole-rock geochemical analyses and Hf isotope are undertaken for the monzogranite in Niubiziliang area with the aim of constraining its formation time,petrogenesis and the regional tectonic setting. The zircons from monzogranite are euhedral-subhedral in shape,and display rhythm growth zoning,indicating a magmatic origin. LA-ICP-MS zircon U-Pb dating indicates the monzogranite formed most probably in the Late Devonian( 359. 0 ± 2. 6 Ma). The monzogranite has Si O2= 74. 69%--76. 11%,Al2O3=12. 07%--12. 81%,Na2 O + K2 O = 8. 24%--8. 70%,Na2 O / K2 O = 0. 60--0. 68,A / CNK > 1,which shows that it belongs to high-Si and high-K weakly peraluminous calc-alkaline series. The monzogranite is enriched in K,Rb,Th( LILEs) and La,Ce,Sm,Nd( LREEs); and depleted in Ba,U( HREEs) and Ta,Nb( HFSEs).Their zircon εHf( t) values range from 1. 21 to 3. 46,in response to their two-stage Hf model ages( TDM2) ranging from 1 034 Ma to 1 159 Ma,respectively,indicating that the primary magma was derived from the young crust in Meso-Neoproterozoic. Combined with the regional geological evolution background,it is considered that the Niubiziliang monzogranite formed the closure of North Qaidam ocean,which was the stretching stage product after the collision between Qaidam block and Qilian block.

Zircon U-Pb geochronology and geochemistry of syenogranitesin western Niubiziliang,northwestern Qaidam,Qinghai

The study presents the results of U-Pb dating of zircons and whole-rock geochemical analyses of a syenogranite located in the western Niubiziliang area,China with the aim of determining its formation time,petrogenesis and the regional tectonic setting. Zircons within the syenogranite are euhedral-subhedral and display rhythmic growth zoning,indicating a magmatic origin. Zircon U-Pb data obtained by LA-ICP-MS indicate the syenogranite formed in the Late Permian (260.7±1.5 Ma). The w(SiO_2) of syenogranites is 70.82%--73.59%,w(Al_2O_3) is 13.49%--14.82%,and w(Na_2O + K_2O) is 7.85%--8.52%,and yield K_2O/Na_2O ratios of 1.06--1.26. Therefore,the syenogranites belong to the high-K calc-alkaline and metaluminous (A/CNK< 1,A/NK > 1) series which display I-type granites similarly. The syenogranites also show the geochemical characteristics of volcanic arc rocks,being enriched in large-ion lithophile elements (LILEs; K,Rb) and light rare-earth elements (LREEs; La,Ce,Sm,Nd),but depleted in high field strength elements( HFSEs; Ta,Nb,P,Ti). On the whole,trace element ratios are close to the mean of the Earth's crust,indicating a lowercrust magma source. The low Sr (161--214) ×10^(-6) and Yb (1.08--1.80)×10^(-6) concentrations indicate that plagioclase and hornblende are residual mineral phases in the source. The regional geology and whole-rock geochemistry suggest that the formation of the syenogranites was related to subduction of the Zongwulong Ocean crust,and the north margin of Qaidam Block during the Late Permian was in an active continental margin tectonic setting.

NucliSens miniMag与QIAamp系统检测血清丙型肝炎病毒RNA效能比较

目的比较研究NucliSens miniMag与QIAamp系统检测血清丙型肝炎病毒(HCV)RNA的效能。方法2021年6月~2023年6月我院收集的103例抗-HCV阳性血清标本,分别采用NucliSens miniMag系统(方法A)和QIAamp Viral RNA Mini Kit(方法B)提取HCV RNA,采用实时荧光定量RT-PCR法检测血清HCV RNA载量。取高载量和低载量两份标本,分批重复检测,计算两种方法批内变异系数(CV)。取HCV RNA强阳性质控标本,梯度稀释后检测,评估两种方法检测的敏感度。结果在103例血清抗-HCV阳性血清标本中,经方法A和方法B提取核酸,检测血清HCV RNA阳性率分别为86.4%和82.5%,差异无统计学意义(P>0.05);方法A提取核酸检测的血清HCV RNA载量为(5.4±1.2)lg IU/mL,方法B检测结果为(5.0±1.6)lg IU/mL,差异有统计学意义(t=2.078,P=0.039);方法A提取核酸检测血清HCV RNA载量低值和高值的CV分别为2.4%和2.2%,方法B检测为4.7%和4.5%,方法A提取核酸检测HCV RNA的重复性优于方法B;方法A提取检测血清HCV RNA最低载量为2.8×10^(-6)lg IU/mL,低于方法B检测的3.5×10^(-6)lg IU/mL,表明更灵敏。结论与QIAamp Viral RNA Mini Kit相比,NucliSens miniMag系统检测血清HCV RNA的效能更高。

Efficacy and safety of dacomitinib as first-line treatment for advanced non-small cell lung cancer patients with epidermal growth factor receptor 21L858R mutation:A multicenter,case-series study in China

Objective:To provide real-world evidence for the application of first-line dacomitinib treatment for epidermal growth factor receptor(EGFR)21L858R mutant non-small cell lung cancer(NSCLC)patients in China and to explore the factors influencing the efficacy and safety.Methods:A longitudinal,consecutive case-series,multicenter study with mixed prospective and retrospective data was conducted.The primary endpoint was progression-free survival(PFS),and the secondary endpoints included duration of treatment(DOT),overall survival(OS),objective response rate(ORR),disease control rate(DCR)and safety.Results:A total of 155 EGFR 21L858R mutant patients treated with first-line dacomitinib were included.The median follow-up time for these patients was 20.4 months.Among 134 patients with evaluable lesions,the ORR was 70.9%and the DCR was 96.3%.The median PFS was 16.3[95%confidence interval(95%CI),13.7−18.9]months.Multivariate Cox regression analysis suggested that the baseline brain metastasis(BM)status[with vs.without BM:hazard ratio(HR),1.331;95%CI,0.720−2.458;P=0.361]and initial doses(45 mg vs.30 mg:HR,0.837;95%CI,0.427−1.641;P=0.604)did not significantly affect the median PFS.The median DOT was 21.0(95%CI,17.5−24.6)months and the median OS was not reached.Genetic tests were performed in 64 patients after progression,among whom 29(45.3%)patients developed the EGFR 20T790M mutation.In addition,among the 46 patients who discontinued dacomitinib treatment after progression,31(67.4%)patients received subsequent third-generation EGFR-tyrosine kinase inhibitors.The most common grade 3−4 adverse events were rash(10.4%),diarrhea(9.1%),stomatitis(7.1%)and paronychia(4.5%).The incidence of grade 3−4 rash was significantly higher in the 45 mg group than that in the 30 mg group(21.9%vs.7.5%,P=0.042).Conclusions:First-line dacomitinib treatment demonstrated promising efficacy and tolerable adverse events among EGFR 21L858R mutant NSCLC patients in China.

应用Tsallis算法和关键度度量的决策树构建

决策树是解决分类问题的重要方法,目前已经提出多种决策树算法,如ID3、C4. 5和CART,它们代表属性分割的普遍标准,即香农熵、信息增益率和基尼系数,但这些算法相互独立,各自优势无法统一。针对该问题,通过研究Tsallis熵,提出Tsallis算法,并基于该算法构建决策树,最后在此基础上提出关键度度量的概念,进一步弥补了叶节点以"少数服从多数"标识分类的缺陷。实验结果表明:该方案精度高、规模小。

循证图书馆信息实践(EBLIP):历史演进与理论框架

循证图书馆信息实践(EBLIP)是一种引入循证的专业决策方法,为图书馆信息服务过程中不断变化的问题提供解决方案,并在与变化的环境相适应的过程中予以发展和改进。文章针对循证图书馆信息实践的历史演进与理论框架,包括历届EBLIP(EBL)国际会议、EBLIP新5A模型的流程循环及构成要素、证据类型等进行了系统性梳理,以为我国深入开展EBLIP研究与实践奠定理论基础。

Solitaire支架联合Navien颅内支撑导管治疗急性缺血性脑卒中的效果及预后影响因素分析

目的探讨Solitaire支架联合Navien颅内支撑导管治疗急性缺血性脑卒中的效果及预后影响因素。方法收集2017年1月至2020年12月在承德医学院附属医院接受治疗的120例急性缺血性脑卒中患者的临床资料。根据术后3个月的预后情况分为预后良好组(n=97)和预后不良组(n=23)。统计120例患者术后即刻和术后2周血管再通率;预后不良的影响因素分析采用Logistic回归分析。结果120例患者,术后即刻再通率为100%,术后2周再通率为95.83%。经Logistic回归分析显示,合并高血压、合并糖尿病、合并心房颤动、合并颈内动脉闭塞、术后存在症状性脑出血、发病至入院时间长、入院时Alberta卒中项目早期计算机断层扫描评分(pc-ASPECTS)低、术前美国国立卫生院神经功能缺损评分(NIHSS)高、取栓次数多为影响急性缺血性脑卒中患者预后不良的独立危险因素(P<0.05)。结论Solitaire支架联合Navien颅内支撑导管治疗有利于提高血管再通率。合并高血压、糖尿病、心房颤动、颈内动脉闭塞、术后存在症状性脑出血、发病至入院时间长、入院时pc-ASPECTS评分低、NIHSS评分高及取栓次数多为急性缺血性脑卒中患者预后不良的危险因素。

LISA与INSURE对NRDS早产患儿脑氧代谢、氧合及临床预后的影响

目的探究低侵入性肺表面活性物质给药(LISA)与气管插管-注入肺表面活性物质-拔管(INSURE)对新生儿呼吸窘迫综合征(NRDS)早产儿患脑氧代谢、氧合及临床预后的影响。方法选择2020年1月—2021年12月本院新生儿科收治的124例NRDS早产患儿,分为对照组60例和观察组64例。对照组患儿常规给予INSURE技术治疗,观察组患儿给予LISA技术治疗,分析两组患儿治疗情况、脑氧代谢、全身氧代谢及临床预后。结果观察组患儿插管用时、无创呼吸支持时间短于对照组,72 h内机械通气率低于对照组,差异有统计学意义(P<0.05),而肺表面活性物质二次给药率与对照组比较差异无统计学意义(P>0.05);随着时间推移,两组患儿脑氧饱和度(ScO_(2))水平均先升后降,但观察组用药期间、用药后5 min的ScO_(2)水平低于对照组,差异均有统计学意义(P<0.05);两组患儿治疗前、治疗24 h后的血pH值比较差异均无统计学意义(P>0.05),治疗24 h后的血氧分压(PaO_(2))、氧合指数较治疗前提高,血二氧化碳分压(PaCO_(2))水平降低,且均以观察组更明显,差异均有统计学意义(P<0.05);观察组患儿心动过缓、插管所致损伤的不良反应发生率和颅内出血、支气管肺发育不良的并发症发生率低于对照组,住院时间短于对照组,差异有统计学意义(P<0.05),两组死亡率和其余不良反应、并发症发生率比较差异无统计学意义(P>0.05)。结论相比于INSURE技术,LISA技术治疗对NRDS早产儿脑氧代谢、氧合状况影响更小,更有利于减少患儿机械通气率、不良反应和并发症发生率,改善患儿临床预后。

猪源肠外致病性大肠杆菌抗体间接ELISA检测方法的建立

利用制备的猪源肠外致病性大肠杆菌(ExPEC)全菌体蛋白建立一种检测猪源ExPEC抗体的间接ELISA方法。将2株猪源ExPEC SDjie18-10(O;)、HByan18-2(O;)超声裂解的全菌体蛋白作为包被抗原,对反应条件进行优化,建立检测猪源ExPEC抗体的间接ELISA方法,并进行临床应用与评价。该方法的最佳条件:包被抗原浓度为15μg/m L,37℃1 h+4℃过夜;2%BSA于37℃封闭2 h;血清稀释度为1∶800,37℃孵育30 min;酶标二抗稀释度为1∶5 000,37℃作用30 min;显色时间为37℃15 min。该方法可特异性检测猪源ExPEC抗体,阳性血清稀释至1∶6 400仍可检出,与其他猪病原阳性血清均无交叉反应,批内及批间变异系数均小于10%。应用间接ELISA与MAT进行符合性比较及临床猪血清样品感染抗体的同步检测,两种方法的符合率分别为93.33%和94.50%且无显著性差异(P>0.05),具有较高的均一性,同时间接ELISA的感染抗体阳性检出率(19.00%)略高于MAT(17.50%),两者检测结果高度一致(K=0.816)。基于猪源ExPEC全菌体蛋白建立的猪源ExPEC抗体间接ELISA检测方法,具有良好的特异性、敏感性和重复性以及临床应用的可靠性,可用于猪源ExPEC的免疫监测和流行病学调查。

基于Havriliak-Negami介电模型的油纸绝缘老化参数提取

电力变压器是电能传输中最重要的设备之一,检测变压器老化状态具有重要意义。为了对变压器内油纸绝缘的老化状态进行有效评估,文中通过频域介电谱法(FDS)研究了不同老化程度下油纸绝缘的介电特性,并通过引入Havriliak-Negami(H-N)模型建立了特征参量与老化时间之间的关系,最后将此方法应用于现场变压器的测试,进行了验证。结果表明:随着老化程度的加深,FDS曲线在高、低频段变化不明显,中频段显著增大,总体曲线呈“枣核”状;依据H-N模型提取的特征参量与老化程度具有良好的对应关系;对现场变压器的应用验证了此方法对于评估变压器老化状态的可行性。

Pathogenesis of non-alcoholic fatty liver disease in children and adolescence: From “two hit theory” to “multiple hit model”

Nonalcoholic fatty liver disease(NAFLD) has become the dominant form of chronic liver disease in children and adolescents with the increasing prevalence of obesity worldwide. NAFLD represents a wide spectrum of conditions, ranging from fatty liver-which generally follows a benign, non-progressive clinical course-to non-alcoholic steatohepatitis, a subset of NAFLD that may progress to cirrhosis and end-stage liver disease or liver carcinoma. The underlying pathophysiological mechanism of "pediatric" NAFLD remains unclear, although it is strongly associated with obesity and insulin resistance. In this review we provide a general overview on the current understanding of NAFLD in children and adolescents, which underpins practice, enabling early diagnosis and appropriate therapeutic intervention for this life-threatening liver disease.

基于Simulink的多体机械系统模型转换方法设计与实践

模块框图作为成熟的图形化建模技术应用十分广泛,采用该技术的MATLAB/SimMechanics可进行多体机械系统的建模和仿真,然而对于建模精度要求高、需要实时仿真的柔性、大型多体机械系统比如空间站来说,SimMechanics有明显不足,而DARTSM软件包可对航天器机械系统进行高精度实时仿真.本文深度解析这两款软件的底层建模技术,根据模型信息的对等关系,设计出模型转换的具体方法,通过C++编程,开发出模型转换程序,从而将航天器多体机械系统的SimMechanics模型转换为DARTSM模型.通过本文的模型转换方法和程序,可以将两款不同软件各自的优点结合到一起,使得SimMechanics间接地拥有处理柔性体和实时仿真的能力,同时也解决了DARTSM软件包缺乏图形化建模界面的问题,具有一定的工程应用价值.

Effect of lifestyle intervention on non-alcoholic fatty liver disease in Chinese obese children

AIM: To investigate the effect of lifestyle intervention on non-alcoholic fatty liver disease (NAFLD) in Chinese obese children. METHODS: Seventy-six obese children aged from 10 to 17 years with NAFLD were enrolled for a one-month intervention and divided randomly into three groups. Group1, consisting of 38 obese children, was an untreated control group without any intervention. Group 2, consisting of 19 obese children in summer camp, was strictly controlled only by life style intervention. Group 3, consisting of 19 obese children, received oral vitamin E therapy at a dose of 100 mg/d. The height, weight, fasting blood glucose (FBG), fasting serum insulin (FINS), plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TCHO) and homeostasis model assent- insulin resistance (HOMA-IR) were measured at baseline and after one month. All patients were underwent to an ultrasonographic study of the liver performed by one operator who was blinded to the groups. RESULTS: The monitor indices of BMI, ALT, AST, TG, TCHO and HOMA-IR were successfully improved except in group 1. BMI and ALT in group 2 were reduced more significantly than in group 3 (2.44 ± 0.82 vs 1.45 ± 0.80, P = 0.001; 88.58 ± 39.99 vs 63.69 ± 27.05, P = 0.040, respectively).CONCLUSION: Both a short-term lifestyle intervention and vitamin E therapy have an effect on NAFLD in obese children. Compared with vitamin E, lifestyle intervention is more effective. Therefore, lifestyle intervention should represent the first step in the management of children with NAFLD.

Limit equilibrium method(LEM) of slope stability and calculation of comprehensive factor of safety with double strength-reduction technique

When the slope is in critical limit equilibrium(LE) state, the strength parameters have different contribution to each other on maintaining slope stability. That is to say that the strength parameters are not simultaneously reduced. Hence, the LE stress method is established to analyze the slope stability by employing the double strengthreduction(DSR) technique in this work. For calculation model of slope stability under the DSR technique, the general nonlinear Mohr–Coulomb(M–C) criterion is used to describe the shear failure of slope. Meanwhile, the average and polar diameter methods via the DSR technique are both adopted to calculate the comprehensive factor of safety(FOS) of slope. To extend the application of the polar diameter method, the original method is improved in the proposed method. After comparison and analysis on some slope examples, the proposed method's feasibility is verified. Thereafter, the stability charts of slope suitable for engineering application are drawn. Moreover, the studies show that:(1) the average method yields similar results as that of the polardiameter method;(2) compared with the traditional uniform strength-reduction(USR) technique, the slope stability obtained using the DSR techniquetends to be more unsafe; and(3) for a slope in the critical LE state, the strength parameter φ, i.e., internal friction angle, has greater contribution on the slope stability than the strength parameters c, i.e., cohesion.

Geochronology, Geochemistry and Sr-Nd-Pb-Hf Isotopes of No. I Complex from the Shitoukengde Ni–Cu Sulfide Deposit in the Eastern Kunlun Orogen, Western China: Implications for the Magmatic Source, Geodynamic Setting and Genesis

The Shitoukengde Ni-Cu deposit, located in the Eastern Kunlun Orogen, comprises three mafic-ultramafic complexes, with the No. I complex hosting six Ni-Cu orebodies found recently. The deposit is hosted in the small ultramafic bodies intruding Proterozoic metamorphic rocks. Complexes at Shitoukengde contain all kinds of mafic-ultramafic rocks, and olivine websterite and pyroxene peridotite are the most important Ni-Cu-hosted rocks. Zircon U-Pb dating suggests that the Shitoukengde Ni-Cu deposit formed in late Silurian （426-422 Ma）, and their zircons have ~Hf（t） values of-9.4 to 5.9 with the older TDMm ages （0.80-1.42 Ga）. Mafic-ultramafic rocks from the No. I complex show the similar rare earth and trace element patterns, which are enriched in light rare earth elements and large ion iithophile elements （e.g., K, Rb, Th） and depleted in heavy rare earth elements and high field strength elements （e.g., Ta, Nb, Zr, Ti）. Sulfides from the deposit have the slightly higher ~34S values of 1.9-4.3%o than the mantle （0 ~ 2%o）. The major and trace element characteristics, and Sr-Nd-Pb and Hf, S isotopes indicate that their parental magmas originated from a metasomatised, asthenospheric mantle source which had previously been modified by subduction-related fluids, and experienced significant crustal contamination both in the magma chamber and during ascent triggering S oversaturation by addition of S and Si, that resulted in the deposition and enrichment of sulfides. Combined with the tectonic evolution, we suggest that the Shitoukengde Ni-Cu deposit formed in the post-collisional, extensional regime related to the subducted oceanic slab break-off after the Wanbaogou oceanic basalt plateau collaged northward to the Qaidam Block in late Silurian.

Non-alcoholic fatty liver disease:An early mediator predicting metabolic syndrome in obese children?

AIM:To investigate if non-alcoholic fatty liver disease (NAFLD) is an early mediator for prediction of metabolic syndrome,and if liver B-ultrasound can be used for its diagnosis.METHODS:We classified 861 obese children (6-16 years old) into three subgroups:group 0 (normal liver in ultrasound and normal transaminases);group 1 (fatty liver in ultrasound and normal transaminases);and group 2 (fatty liver in ultrasound and elevated transaminases).We measured the body mass index,waist and hip circumference,blood pressure,fasting blood glucose,insulin,homeostasis model assessment of insulin resistance (HOMA-IR),whole-body insulin sensitivity index (WBISI),lipid profile and transaminases in all the participants.The risk of developing metabolic syndrome (MS) was assessed according to the degree of liver fatty infiltration based on the B-ultrasound examination.RESULTS:Among the 861 obese children,587 (68.18%) were classified as having NAFLD,and 221 (25.67%) as having MS.The prevalence of MS in NAFLD children (groups 1 and 2) was 37.64% (221/587),which was much higher than that in non-NAFLD group (group 0,12.04%) (P < 0.01).There were significantly higher incidences concerning every component of MS in group 2 compared with group 0 (P < 0.05).The incidence of NAFLD in MS patients was 84.61% (187/221),which was significantly higher than that of hypertension (57.46%,127/221) and glucose metabolic anomalies (22.62%,50/221),and almost equal to the prevalence of dyslipidemia (89.14%,197/221).Based on the B-ultrasound scales,the presence of moderate and severe liver fatty infiltration carried a high risk of hypertension [odds ratio (OR):2.18,95% confidence interval (95% CI):1.27-3.75],dyslipidemia (OR:7.99,95% CI:4.34-14.73),impaired fasting glucose (OR:3.65,95% CI:1.04-12.85),and whole MS (OR:3.77;95% CI:1.90-7.47,P < 0.01).The state of insulin resistance (calculated by HOMA-IR and WBISI) deteriorated as the degree of fatty infiltration increased.CONCLUSION:NAFLD is not only a liver disease,but also an early mediator that reflects metabolic disorder,and liver B-ultrasound can be a useful tool for MS screening.

载中药聚乳酸多孔纳米纤维医用敷料

为构筑人体可吸收、抗菌消炎且轻薄柔软的可用于伤口愈合的医用敷料,以聚乳酸为原料,掺杂板蓝根(RI)、柴胡(BC)和茶多酚(GTP)等中药成分,采用氯仿与丙酮二溶剂体系,借助静电纺技术制备聚乳酸(PLA)多孔纳米纤维载中药敷料。通过扫描电镜、红外光谱仪、X射线衍射仪(XRD)和接触角测试仪等手段分析了载中药敷料的微观结构、润湿性能、保水吸液性、抗菌性以及体外降解性能等。结果表明:采用氯仿和丙酮二溶剂体系制备的载中药敷料其纤维具有多孔特征,纤维直径为747~1 550 nm。敷料中所载板蓝根、柴胡、茶多酚与聚乳酸间并未发生负面改性的化学反应。载板蓝根、柴胡、茶多酚的敷料在载药量为3%时对金黄色葡萄球菌抑菌率分别为79.2%、82.5%、75.7%,对大肠杆菌抑菌率分别为79.1%、80.2%、73.9%。同时,较纯聚乳酸敷料,载中药敷料具有较好的透气性和体外降解性,其保水吸液性均提高20%以上,适合用作伤口敷料。

Combined influence of nonlinearity and dilation on slope stability evaluated by upper-bound limit analysis

The combined influence of nonlinearity and dilation on slope stability was evaluated using the upper-bound limit analysis theorem.The mechanism of slope collapse was analyzed by dividing it into arbitrary discrete soil blocks with the nonlinear Mohr–Coulomb failure criterion and nonassociated flow rule.The multipoint tangent(multi-tangent) technique was used to analyze the slope stability by linearizing the nonlinear failure criterion.A general expression for the slope safety factor was derived based on the virtual work principle and the strength reduction technique,and the global slope safety factor can be obtained by the optimization method of nonlinear sequential quadratic programming.The results show better agreement with previous research result when the nonlinear failure criterion reduces to a linear failure criterion or the non-associated flow rule reduces to an associated flow rule,which demonstrates the rationality of the presented method.Slope safety factors calculated by the multi-tangent inclined-slices technique were smaller than those obtained by the traditional single-tangent inclined-slices technique.The results show that the multi-tangent inclined-slices technique is a safe and effective method of slope stability limit analysis.The combined effect of nonlinearity and dilation on slope stability was analyzed,and the parameter analysis indicates that nonlinearity and dilation have significant influence on the result of slope stability analysis.

Advanced reliability analysis of slopes in spatially variable soils using multivariate adaptive regression splines

This study aims to extend the multivariate adaptive regression splines(MARS)-Monte Carlo simulation(MCS) method for reliability analysis of slopes in spatially variable soils. This approach is used to explore the influences of the multiscale spatial variability of soil properties on the probability of failure(P_f) of the slopes. In the proposed approach, the relationship between the factor of safety and the soil strength parameters characterized with spatial variability is approximated by the MARS, with the aid of Karhunen-Loeve expansion. MCS is subsequently performed on the established MARS model to evaluate Pf.Finally, a nominally homogeneous cohesive-frictional slope and a heterogeneous cohesive slope, which are both characterized with different spatial variabilities, are utilized to illustrate the proposed approach.Results showed that the proposed approach can estimate the P_f of the slopes efficiently in spatially variable soils with sufficient accuracy. Moreover, the approach is relatively robust to the influence of different statistics of soil properties, thereby making it an effective and practical tool for addressing slope reliability problems concerning time-consuming deterministic stability models with low levels of P_f.Furthermore, disregarding the multiscale spatial variability of soil properties can overestimate or underestimate the P_f. Although the difference is small in general, the multiscale spatial variability of the soil properties must still be considered in the reliability analysis of heterogeneous slopes, especially for those highly related to cost effective and accurate designs.

固定化SRB包埋颗粒组分优选及处理含SO_(4)^(2-)废水效果研究

赣南离子型稀土矿尾水存在SO42-含量高、pH偏低的问题,影响后续微生物对尾水其他组分(NH_(4)^(+)-N、NO_(3)^(-)-N)的处理,拟采用硫酸盐还原菌(SRB)包埋颗粒对水体中SO_(4)^(2-)进行去除,同时提升水体pH。通过对SRB包埋颗粒表面吸附材料、还原激活材料、内聚碳源和固体酸水解材料4个组分进行实验研究优选SRB包埋颗粒组分,结果表明,凹凸棒石粉作为SRB包埋颗粒表面吸附材料应用效果比较好,纳米零价铁对SRB的还原激活作用相对更好,内聚碳源及固体酸水解材料组合以玉米芯、花生壳与沸石粉、磁铁矿粉的组合效果比较理想。在此基础上筛选制备出4种包埋颗粒,通过厌氧三角瓶验证其对模拟废水中SO_(4)^(2-)的去除效果,发现制备的4种包埋颗粒经过10 d的实验对SO_(4)^(2-)的去除率都在60%以上,去除率最高的是花生壳-Fe_(3)O_(4)组合包埋颗粒,为80.20%。