Morphological and Sulfur-Isotopic Characteristics of Pyrites in the Deep Sediments from Xisha Trough,South China Sea

Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.

Persistent Variations in the East Asian Trough from March to April and the Possible Mechanism

The East Asian trough(EAT)profoundly influences the East Asian spring climate.In this study,the relationship of the EATs among the three spring months is investigated.Correlation analysis shows that the variation in March EAT is closely related to that of April EAT.Extended empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April EATs.The positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to April.Further investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian Ocean.The dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the EAT in March−April.The SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−April.Besides the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to April.These three impact factors are generally independent of each other,jointly explaining large variations in the EAT EEOF1.Moreover,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.

Improving Heat Transfer in Parabolic Trough Solar Collectors by Magnetic Nanofluids

A parabolic trough solar collector(PTSC)converts solar radiation into thermal energy.However,low thermal efficiency of PTSC poses a hindrance to the deployment of solar thermal power plants.Thermal performance of PTSC is enhanced in this study by incorporating magnetic nanoparticles into the working fluid.The circular receiver pipe,with dimensions of 66 mm diameter,2 mm thickness,and 24 m length,is exposed to uniform temperature and velocity conditions.The working fluid,Therminol-66,is supplemented with Fe3O4 magnetic nanoparticles at concentrations ranging from 1%to 4%.The findings demonstrate that the inclusion of nanoparticles increases the convective heat transfer coefficient(HTC)of the PTSC,with higher nanoparticle volume fractions leading to greater heat transfer but increased pressure drop.The thermal enhancement factor(TEF)of the PTSC is positively affected by the volume fraction of nanoparticles,both with and without a magnetic field.Notably,the scenario with a 4%nanoparticle volume fraction and a magnetic field strength of 250 G exhibits the highest TEF,indicating superior thermal performance.These findings offer potential avenues for improving the efficiency of PTSCs in solar thermal plants by introducing magnetic nanoparticles into the working fluid.

Geological characteristics of the southern segment of the Late Sinian–Early Cambrian Deyang-Anyue rift trough in Sichuan Basin, SW China

Based on the latest drilling, seismic and field outcrop data, the geological characteristics(e.g. strata, development and sedimentary evolution) of the southern segment of the Late Sinian–Early Cambrian Deyang–Anyue rift trough in the Sichuan Basin are analyzed. First, the strata in the southern segment are complete. The first to second members of Dengying Formation(Deng 1 + Deng 2) are found with relatively stable thickness(400–550 m), and the third to fourth members(Deng 3+ Deng 4) show great thickness difference between the marginal trough and the inner trough, which is up to 250 m. The Cambrian Maidiping Formation and Qiongzhusi Formation in southern Sichuan Basin are relatively thin, with the thickness changing greatly and frequently. Second, the Deyang–Anyue rift trough extended southward during the Deng 4 period, affecting southern Sichuan Basin. Compared to the middle and northern segments of the rift trough, the southern segment is generally wide, gentle and shallow, with multiple steps, and alternating uplifts and sags, which are distributed in finger shape. Third, the Deng 1 + Deng 2 in southern Sichuan Basin records the dominance of carbonate platform and unobvious sedimentary differentiation, and the Deng 4 exhibits obvious sedimentary differentiation, namely, basin–slope–secondary slope–slope–secondary slope–platform margin–restricted platform, from the inner trough to the marginal trough. Fourth, the rift trough in southern Sichuan Basin has evolved in four stages: stabilization of Deng 1–Deng 2, initialization of Deng 3–Deng 4, filling of Maidiping–Qiongzhusi, and extinction of Canglangpu Formation.

Clinical Evaluation of a Vancomycin Dosage Strategy Based on a Serum Trough Concentration Model in Elderly Patients with Severe Pneumonia

Objective This study aimed to evaluate the clinical benefits of a vancomycin dosage strategy based on a serum trough concentration model in elderly patients.Methods This prospective single-center, open-label, randomized controlled trial categorized 66 elderly patients with severe pneumonia into study and control groups. The control group received vancomycin using a regimen decided by the attending physician. Meanwhile, the study group received individualized vancomycin therapy with a dosing strategy based on a serum trough concentration model. The primary endpoint was the proportion of patients with serum trough concentrations reaching the target values.The secondary endpoints were clinical response, vancomycin treatment duration, and vancomycinassociated acute kidney injury(VA-AKI) occurrence.Results All patients were at least 60 years old(median age = 81 years). The proportion of patients with target trough concentration achievement(≥ 15 mg/L) with the initial vancomycin regimen was significantly higher in the study group compared to the control group(75.8% vs. 42.4%, P = 0.006).Forty-five patients(68.2%) achieved clinical success, the median duration of vancomycin therapy was10.0 days, and VA-AKI occurred in eight patients(12.1%). However, there were no significant differences in these parameters between the two groups. The model for predicting vancomycin trough concentrations was upgraded to: serum trough concentration(mg/L) = 17.194-0.104 × creatinine clearance rate(mL/min) + 0.313 × vancomycin daily dose [mg/(kg·d)].Conclusion A vancomycin dosage strategy based on a serum trough concentration model can improve the proportion of patients achieving target trough concentrations in elderly patients with severe pneumonia.

The Mamfe Basin in the southern Benue trough extension between Cameroon and Nigeria:Gem origin and problem of lithostratigraphic nomenclature and marine transgression

The Mamfe Basin has been the subject of many studies,but some debates persist,especially concerning the stratigraphic nomenclature,corundum origin,and marine transgression.The aims of this work are(1)to propose a new lithostratigraphic nomenclature of the Mamfe Basin formation based on new field observations,(2)to determine the source rock distribution and the origin of gem deposits and(3)to correlate the Cameroon section of the Mamfe Basin with the Nigerian deposits.The main results show that the name Manyu River Group is more appropriate as the Manyu River crosses all the facies in the Mamfe sedimentary Basin belonging to the Manyu Division.According to the facies analysis,the age of deposition,the mineralogic and geochemical data such as the V vs.Al2O3andΣREE vs.Al_(2)O_(3),TiO_(2)MgO,Na_(2)O,P_(2)O_(5),and CaO diagrams,this Group is composed of at least five Formations,including four Cretaceous Formations,from bottom to top:the Etoko Formation(alluvial and fluvial channel to fluvio-lacustrine deposits),the Nfaitok Formation(lagoonal deposits),the Bachuo Ntai Formation(fluvial braided channels or fluvio-deltaic environment)and the Eyumojock/NsanaragatiFormation(fluvio-lacustrine deposits)and the new Cenozoic Formation named Bakebe Formation(fluvio-lacustrine deposits).The gem minerals such as corundum,rutile,or tourmaline in the Cretaceous deposits of the Mamfe Basin are mainly detrital as indicated by the presence of worn shapes and fragments of these minerals.The presence of sapphire in the AlboCenomanian deposits indicates a Precambrian age of the felsic source rock,likely the plutonic rocks such as granite or pegmatite as indicated by the abundance of tourmaline and high LREE/HREE ratios(14.81–34.29)and slightly negative and positive Eu anomalies(0.85–1.15).This marine incursion in the Mamfe Basin was probably from West Nigeria,according to the geographic location of the Mamfe Basin and the general palaeogeographic evolution of the Benue Trough.

Investigation and simulation of parabolic trough collector with the presence of hybrid nanofluid in the finned receiver tube

The present study discusses the thermal performance of the receiver tube,which contains a wall with various fin shapes in the parabolic trough collector.Inserted fins and bulge surfaces of the inner wall of the receiver tube increase the turbulent fluid flow.In pursuance of uniform distribution of heat transfer,various fin shapes such as square-shape,circle-shape,triangle-shape,and combined square-circle shapes were inserted,examined,and compared.A study of the temperature differences and fluid flow is meaningful for this project therefore finite volume method was used to investigate heat transfer.Also,hybrid Nano-Fluid AL_(2)O_(3-)CuO,TiO_(2-)Cu,and AgMgO were applied to increase thermal diffusivity.When the combined square-circle-shaped fin was inserted,the thermal peak of fluid flow in the receiver tube was lower than the other studied fin shapes by almost 1%.Besides,the hybrid nano-fluid Ag-MgO Syltherm-oil-800 has lower thermal waste in comparison to others by more than 3%.

Modified Circumpolar Deep Water inflow to the Dotson-Getz Trough in the summers of 2020 and 2022

The melting of the West Antarctic Ice Shelf has increased since the 1990s,driven by the relatively warm Circumpolar Deep Water(CDW)that penetrates into the West Antarctic Ice Shelf cavities through submarine glacial troughs across the continental shelf.In this study,temperature,salinity,and current velocity data obtained by the Chinese National Antarctic Research Expedition in the Dotson-Getz Trough(DGT)shows clear differences in distribution of modified Circumpolar Deep Water(mCDW)in the summers of 2020 and 2022.Combined with contemporaneous wind data and additional temperature and salinity data from instrumented seals,the processes and mechanisms responsible for this variation are discussed.Compared with 2020,there is a significant increase in mCDW thickness in 2022,with a doubling of total heat content as the mCDW inflow path across the DGT shifts towards the eastern bank.We propose that a southward shift in the westerly winds in the summer of 2022 moved the upper oceanic divergence zone southward towards the continental slope,promoting the upwelling of mCDW above 500 m.Concurrently,stronger westerly winds over the continental slope strengthened the eastward undercurrent,increasing the transport of this mCDW and its associated heat content to the DGT through Ekman dynamics.These observations show there is strong interannual variability in the strength,path and extent of mCDW inflows to the DGT and that care must be taken when planning observation programs for long-term monitoring of the oceanic heat input to the ice shelves of this globally significant region.

Effect of Different Silica Fumes on Properties of Al_(2)O_(3)-SiC-C Castables for Iron Trough

In order to improve the performance of Al_(2)O_(3)-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,calcium aluminate cement as the binder.Several kinds of silica fumes(93SiO_(2),96SiO_(2),and 99SiO_(2))with different particle size distributions and chemical composition were added to research the effects on the properties of castables.The results show that the sample with 99SiO_(2) fume has high water requirement for molding,but the bulk density is the lowest,the apparent porosity is the highest,the oxidation resistance is the worst,and the permanent linear change on heating is low after firing at 1 450 ℃ for 3 h.The bulk density and the apparent porosity of the sample with 93SiO_(2) fume or 96SiO_(2) fume are equivalent,the hot modulus of rupture of the sample with 93SiO_(2) fume is the lowest,and the slag resistance of the sample with 96SiO_(2) fume is the best.The comprehensive performance of the sample with 96SiO_(2) fume is the best.

Evaluating Vancomycin Clinical Outcomes Using Area under the Curve versus Trough Based Dosing Strategies

Background: The 2020 consensus guidelines recommend AUC guided dosing as the preferred monitoring method for vancomycin. AUC based dosing has shown to reduce incidence of acute kidney injury (AKI), utilize lower daily doses in obese patients, and maintain efficacy. Several institutions have adjusted their protocols to utilize AUC guided dosing. However, there are limited studies comparing the clinical outcomes of AUC versus trough monitoring. Methods: This was a retrospective, observational, single centered study. The primary outcome was to evaluate the clinical success of AUC dosing versus trough based dosing of vancomycin for MRSA infections using a composite outcome of afebrile post treatment ( Results: Forty-seven patients were included in this study, 17 in the AUC group and 30 in the trough group. The primary composite outcome showed a significant benefit of AUC dosing (p = 0.04). The composite component culture clearance showed the largest improvement for the AUC group when compared with the trough group (p = 0.03). More patients achieved therapeutic target attainment and reached the target sooner (3 days versus 4 days, p = 0.2) in the AUC group. Over the study course, 94.1% of patients in the AUC group were considered therapeutic compared to 63.8% in the trough group (p = 0.03). Vancomycin levels were collected less frequently in the AUC group (3 versus 4, p = 0.2). Conclusion: The outcomes of this study may suggest AUC guided dosing as a beneficial alternative to trough based dosing. AUC based dosing may improve clinical success which can be further explored in larger prospective clinical trials.

连续电磁剖面法在塔里木盆地麦盖提斜坡裂陷槽深部构造研究中的应用

随着对塔里木盆地深层油气勘探认识不断深入,认为震旦—南华系裂陷槽对烃源岩的发育保存有着重要的控制作用,因此对该区域的裂陷槽探测是油气勘探的重要探索方向。前人研究认为对塔西南地区麦盖提斜坡处存在震旦—南华系裂陷槽,但受限于该区域地震资料品质,对该区域深层结构尤其是对基底和裂陷槽分布形态和范围认知不清。因此,通过一条跨过麦盖提斜坡与叶城凹陷的连续电磁剖面法剖面,结合研究区地质情况与井资料,构建了区域电阻率的物性分层结构,完成了对实际数据的二维反演,获取了该区域的深部电性结构与CEMP剖面的综合地质解释结果。为该区域新元古代裂陷槽发育情况的判断提供了新的电磁证据,也进一步刻画了基底、裂陷槽的电性特征与结构。探测结果认为裂陷主要由正断层控制,呈现裂陷群特点,裂陷多呈半地堑、不对称地堑及堑—垒相间的构造样式,在麦盖提斜坡、叶城凹陷处中部、南部的区域发育两个裂陷群,有利于区域内的烃源岩沉积,其中裂陷内震旦—南华系地层沉积较厚的区域具有较好的深层油气勘探潜力。

万古霉素在重症感染中的治疗药物监测现状及前景

万古霉素被誉为治疗革兰阳性菌感染的最后一道防线,也是推荐的一线用药。因其治疗窗窄,重症患者需监测药物浓度以指导临床安全用药。传统上基于万古霉素谷浓度的治疗药物监测已被临床广泛接受。2009年美国传染病学会(IDSA)指南建议,对于重症患者目标谷浓度为15~20 mg/L。近十余年国内外学者对于该治疗浓度的安全性及有效性评价不一。2020年更新指南提出,肾损伤风险最小、最准确且最佳的给药方法是通过曲线下面积(AUC)指导给药剂量和监测,提倡个体化目标AUC/最低抑菌浓度(MIC)比值为400~600 mg/(h·L)。由此可见目前就万古霉素临床监测指标存在争议。因此,本文就万古霉素治疗重症感染过程中进行治疗浓度监测的手段及策略进行综述,对指导临床合理用药具有重要意义,有助于临床医师制定个体化给药方案,最大程度减少或避免药物毒性。

牛马不同槽——嘉峪关魏晋墓两幅壁画的现实表达与文化意涵

嘉峪关魏晋墓葬壁画描绘了“牛马不同槽”的现象。结合礼仪艺术与世俗绘卷中的同类图像,揭示了此类现象的现实原因,并指出其进入文化层面后的意涵。先秦哲学从牛马习性出发,抽象出了其间的对立统一关系,很多情境中牛马间的对立还可转化为对应,例如祭祀中的牛马,图像中的牛马合犋犁耕、牧马牧牛、牛车鞍马,宗教语境下的牛头马面等。“牛马不同槽”从民间俗语到文献与图像的表达,反映了古代艺术与生活的密切关系。

自体脂肪颗粒移植矫正泪槽畸形的临床效果分析

目的:探讨自体脂肪颗粒移植填充矫正泪槽畸形的临床效果及对其相关并发症进行分析。方法:选取2018年10月-2022年9月在山东省立医院接受诊治的104例泪槽畸形的患者,采用自体脂肪颗粒移植术,术后6个月对患者进行随访,观察和评价手术效果,记录患者出现局部肿胀、瘀斑、术区条索、血肿、感染、脂肪液化坏死、脂肪栓塞等并发症的发生情况。结果:泪沟改善有效率达91.35%,有3例出现肉眼可见的条索,未出现感染、脂肪液化坏死、脂肪栓塞等严重并发症。结论:自体脂肪颗粒移植是纠正泪槽畸形有效和安全的治疗方法。

计及AA-CAES与PTC集成的综合能源系统运行优化与性能分析

为进一步发挥综合能源系统的多能互补优势,提出一种计及先进绝热压缩空气储能(AA-CAES)与槽式太阳能集热器(PTC)集成的综合能源系统(IES-PTC-CAES)优化运行策略。首先,对AA-CAES、PTC以及系统中其他设备进行分析并建立相应模型;进而以经济性、环保性和能效性为优化目标,以设备运行的关键参数为优化变量,基于分时电价建立了协同优化策略,并通过K-means算法将模拟出的典型年负荷聚类为典型日负荷;最终,使用并行式的遗传算法对系统进行寻优,得到不同目标下IES-PTC-CAES的最优运行策略。结果表明:与参考系统相比,IES-PTC-CAES系统经济目标下总成本降低了14.61万元,环保目标下二氧化碳排放量减少了6194.38 kg。

万古霉素治疗药物监测的热点与进展

治疗药物监测是维持万古霉素疗效和预防不良反应的重要手段,并有助于制定个体化的给药剂量方案。随着中国和美国指南关于治疗药物监测指标的更新,以24 h药-时曲线下面积(AUC_(24 h))引导的治疗药物监测逐渐成为热点。与谷浓度引导的治疗药物监测相比,AUC_(24 h)引导的治疗药物监测能够降低万古霉素引起的急性肾损伤的发生率。临床上可以通过贝叶斯法和线性药代动力学方法来实施AUC_(24 h)引导的治疗药物监测,这2种方法均可以实现AUC_(24 h)的预测,达到早期干预的目的。各医疗机构有必要根据机构实际情况选择合适的监测方法。

槽式太阳能集热管内导热油结焦产物特性分析

鉴于槽式太阳能集热管壁面堆积的结焦产物对集热管安全问题及其内导热油流动和换热的影响,分析了某槽式太阳能热发电系统运行3年后集热管结焦产物的表观形貌和产物特性.结果表明:结焦产物在金属内管周向呈现聚光侧较厚、坑洼状的粗糙表面和非聚光侧较薄的非均匀分布;结焦产物颗粒立体感明显,具有结焦团聚焦和分散焦2种形式;结焦产物堆积后真密度为1.2597 g/cm 3,通过DSC蓝宝石法测得比热容为0.83~2.11 J/(g·K);使用闪光法在400℃时测得有结焦产物的不锈钢金属内管样品导热系数为24.05 W/(m·K),比无结焦产物的不锈钢金属内管样品导热系数降低了21.7%,由此说明结焦产物显著影响金属内管的传热性能.

抛物面槽式太阳能集热器球形接头测试系统的研制与应用

球形接头是抛物面槽式太阳能集热器的关键部件,针对球形接头易发生运转卡涩和导热油泄漏问题,研制了一套球形接头性能测试系统。该测试系统可以实现球形接头在旋转、摆转或旋摆联动模式下,以及在导热油温度达393℃和压力达4.1 MPa工况条件下的加速寿命测试。以导热油为传热流体,开展了球形接头在导热油温度为393℃和压力为2.3 MPa工况条件,以及温度、压力变化条件下的性能测试研究,分析了球形接头在模拟12年寿命期的扭矩特性和密封性能,验证了该测试系统运行的稳定性和可靠性,并且关键技术参数的控制精度和测量精度满足使用要求,为球形接头的性能评价提供了技术支撑。

渤海湾盆地庙西北地区古近系沙河街组三段源-汇系统重建

基于钻井岩心和三维地震资料,从物源岩性、分水岭和古水系、搬运通道3个方面对渤海湾盆地庙西北地区物源特征和沉积相展布进行了分析,并通过沉积区古地貌恢复和剥蚀物源区古地貌回溯重建了古近系沙河街组三段(沙三段)沉积时期的源-汇系统。研究结果表明:(1)渤海湾盆地庙西北地区古近系沙三段发育一个完整的近源搬运型源-汇系统,庙西北凸起为物源区,渤东凹陷为主要沉积区;庙西北凸起物源岩性包括中生界花岗岩、下元古界石英片岩及下元古界角砾岩;主分水岭沿凸起长轴呈近南北向展布,古水系散布其间,搬运通道主要为5个古沟谷和2个古断槽;渤东凹陷沙三段主要发育快速堆积的扇三角洲—湖泊相沉积,岩性主要为含砾砂岩、细砂岩及泥岩,分选性和磨圆度均较差,岩石成分及矿物组合均与庙西北凸起石英片岩及花岗岩较为匹配,扇三角洲沉积体呈近东西向展布,在渤东凹陷北部以连片朵状扇三角洲为主,南部为孤立朵状。(2)沙三段沉积期,庙西北凸起剥蚀作用具有“西强东弱”的特征,古分水岭逐渐向西迁移,凸起中部及北部物源面积大、垂向高差大,物源供给能力更强;渤东凹陷沙三段厚度为100~600 m,具有东南薄、西北厚的特征,沉积中心位于区域北部,且北部地层剥蚀作用更强,向东部延伸长度可达3.2 km;扇三角洲的发育位置受控于物源区搬运通道,其发育规模则受控于物源区域面积,渤东凹陷北部及中部扇三角洲沉积体规模更大,是勘探有利区。

广东“18.8”季风槽极端降水事件对流尺度集合预报分析

受季风槽影响,2018年8月30—31日华南地区出现一次极端暴雨过程,单日站点累计降水量达1056.7 mm,刷新了广东有历史纪录以来新的极值。对于此次极端降水事件,常用的业务模式包括欧洲中期天气预报中心全球模式(ECMWF)、日本气象厅谱模式(JMA)和中国气象局广东快速更新同化数值预报系统(CMA-GD),都低估了降水强度。利用深圳市气象局业务对流尺度集合预报系统分析了此次特大暴雨过程,结果表明:对流尺度集合预报系统对本次特大暴雨过程具有比较好的预报能力,概率匹配平均最大雨量达348.7 mm·(24 h)^(-1),集合平均的强降水中心和观测基本一致,观测极值附近区域发生大暴雨(≥150 mm)概率最大值达到80%。选取了较“好”和较“差”集合成员预报进行对比分析,发现较“好”成员预报的强降水中心位置和观测基本一致,而较“差”成员预报的降水中心位置则偏向福建地区。较“好”成员预报出莲花山南侧地面中尺度辐合线较长时间的维持和缓慢移动,导致强降水雨团在莲花山脉附近不断地触发和维持,同时地形的阻挡作用使得对流系统在地形附近区域持续维持,造成了罕见的特大暴雨;而较“差”成员辐合区位于莲花山以北,对流形成后向东、向北移动,最终导致强降水预报位置偏向福建地区。