Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study

Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)formations.Lost circulation material(LCM)is a regular preventive and remedial measure for lost circulation.However,conventional LCMs seem ineffective in high-temperature formations.This may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature conditions.To understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in fractures.We summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling fluid.We conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing temperatures.The results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid viscosity.Smaller,softer,and less frictional LCM particles have lower bridging probability and slower bridging initiation.Smaller particles tend to form dual-particle bridges rather than single-particle bridges.These result in a deeper,tighter,but unstable sealing zone.Reduced drilling fluid viscosity leads to faster and shallower sealing zones.

A new infrageneric classification of Gastrochilus(Orchidaceae:Epidendroideae)based on molecular and morphological data

Gastrochilus is an orchid genus containing 73 species of mainly epiphytic on trees or rocks in mountain forests of tropical and subtropical Asia.Previous phylogenetic analyses and morphological assessments have failed to produce a well-resolved phylogeny at the infrageneric level.In the present study,a new infrageneric classification of Gastrochilus is proposed based on thoroughly morphological and phylogenetic analyses based on 52 species.Our phylogenetic analysis divided the genus into six sections including three new sections,G.sect.Pseudodistichi,G.sect.Brachycaules and G.sect.Acinacifolii.We also reinstate G.suavis to the specific rank.Furthermore,two new species,G.armeniacus Jun Y.Zhang,B.Xu&Yue H.Cheng and G.minjiangensis Jun Y.Zhang,B.Xu&Yue H.Cheng,are described and illustrated.A key to six sections of the genus is presented.

Values of macular ganglion cell-inner plexiform layer and 10-2 visual field measurements in detecting and evaluating glaucoma

AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:Totally 127 eyes from 89 participants(36 eyes of 19 healthy participants,45 eyes of 31 early glaucoma patients and 46 eyes of 39 advanced glaucoma patients)were included.The relationships between the optical coherence tomography(OCT)-derived parameters and VF sensitivity were determined.Patients with early glaucoma were divided into eyes with or without central 10°of the VF damages(CVFDs),and the diagnostic performances of OCT-derived parameters were assessed.RESULTS:In early glaucoma,the mGCIPLT was significantly correlated with 10-2 VF pattern standard deviation(PSD;with average mGCIPLT:β=-0.046,95%CI,-0.067 to-0.024,P<0.001).In advanced glaucoma,the mGCIPLT was related to the 24-2 VF mean deviation(MD;with average mGCIPLT:β=0.397,95%CI,0.199 to 0.595,P<0.001),10-2 VF MD(with average mGCIPLT:β=0.762,95%CI,0.485 to 1.038,P<0.001)and 24-2 VF PSD(with average mGCIPLT:β=0.244,95%CI,0.124 to 0.364,P<0.001).Except for the minimum and superotemporal mGCIPLT,the decrease of mGCIPLT in early glaucomatous eyes with CVFDs was more severe than that of early glaucomatous eyes without CVFDs.The area under the curve(AUC)of the average mGCIPLT(AUC=0.949,95%CI,0.868 to 0.982)was greater than that of the average circumpapillary retinal nerve fiber layer thickness(cpRNFLT;AUC=0.827,95%CI,0.674 to 0.918)and rim area(AUC=0.799,95%CI,0.610 to 0.907)in early glaucomatous eyes with CVFDs versus normal eyes.CONCLUSION:The 10-2 VF and mGCIPLT parameters are complementary to 24-2 VF,cpRNFLT and ONH parameters,especially in detecting early glaucoma with CVFDs and evaluating the severity of advanced glaucoma in group level.

Diagnosing anomalous characteristics of atmospheric water cycle structure during seasonal-scale drought events:A case study in middle and lower reaches of Yangtze River

Anomalous characteristics of the atmospheric water cycle structure are highly significant to the mechanisms of seasonal-scale meteorological droughts.They also play an important role in the identification of indicative predictors of droughts.To better understand the causes of seasonal meteorological droughts in the middle and lower reaches of the Yangtze River(MLRYR),characteristics of the atmospheric water cycle structure at different drought stages were determined using standardized anomalies.The results showed that the total column water vapor(TCWV)was anomalously low during drought occurrence periods.In contrast,there were no anomalous signals at the drought persistence and recovery stages in the MLRYR.Moreover,there was no significant temporal correlation between the TCWV anomaly and seasonal-scale drought index(the 3-month standardized precipitation index(SPI_(3))).During drought events,water vapor that mainly originated from the Bay of Bengal was transported southwest of the MLRYR.Meanwhile,the anomalous signal of water vapor transport was negative at the drought appearance stage.At the drought persistence stage,the negative anomalous signal was the most significant.Water vapor flux divergence in the MLRYR showed significant positive anomalous signals during drought events,and the signal intensity shifted from an increasing to a decreasing trend at different drought stages.In addition,a significant positive correlation existed between the anomaly of water vapor flux divergence and regional SPI_(3).Overall,water vapor flux divergence is more predictive of droughts in the MLRYR.

红芪多糖“脱蛋白-大孔吸附树脂”的纯化富集工艺考察

目的研究红芪多糖(HPS)标准提取物,筛选优化其“脱蛋白-大孔吸附树脂纯化富集”的工艺方法与工艺参数。方法以蛋白脱除率和多糖损失率为指标,比较4种不同方法的脱蛋白效果,并对筛选出的方法进行工艺参数优化;以吸附量和吸附率为指标,考察4种型号大孔吸附树脂(AB-8、D-101、NKA-9、X-5)对HPS的纯化富集效果,并进行相关工艺参数优化;采用苯酚硫酸法和考马斯亮兰法分别测定多糖和蛋白质含量;采用紫外分光光度(UV)和红外光谱(IR)法比较纯化前后多糖的基本特征。结∶果筛选出的脱蛋白方法为Sevag法,优选的树脂为AB-8大孔吸附树脂。通过工艺参数优选,确定的纯化工艺为:10 mg·mL^(-1)粗多糖水溶液,以1/2倍体积氯仿^(-1),∶v/v)混合试剂进行脱蛋白操作2次;除去残留有机溶剂后,以质量浓度为1.5 mg·mL^(-1)的水溶液,上预处理好的AB-8大孔吸附树脂柱[树脂量(g)与上样体10]∶,以2.0 mL·min^(-1)流速循环上样2次,动态吸附后再静态吸附6~8 h,后以30%乙醇1.0 mL·min^(-1)进行洗脱,至洗脱液无明显碱性酒石酸铜反应,收集洗脱液浓缩至与原药1冲洗沉淀,即得HPS。结论验证试验表明,经本工艺纯化富集后,所得HPS样品纯度提高了1.27倍;UV在260,280 nm处未见蛋白质吸收峰;IR表现出更突出的多糖结构特征吸收峰,说明纯化过程有效且未对HPS主要结构产生影响。优选出的HPS脱蛋白和大孔树脂纯化工艺稳定可行,重复性较好,使多糖得到较好的纯化富集,为HPS标准提取物的形成以及其能成为制剂科学化原料药提供了研究基础。

Cavity enhanced measurement of trap frequency in an optical dipole trap

We demonstrate a direct, fluorescence-free measurement of the oscillation frequency of cold atoms in an optical dipole trap based on a high-finesse optical cavity strongly coupled to atoms. The parametric heating spectra of the trapped atoms are obtained by recording the transmitted photons from the cavity with the trap depth is modulated by different frequency.Moreover, in our method the oscillation can be observed directly in the time scale. Being compared to the conventional fluorescence-dependent method, our approach avoids uncertainties associated with the illuminating light and auxiliary imaging optics. This method has the potential application of determining the motion of atoms with stored quantum bits or degenerate gases without destroying them.

Single-photon source with sub-MHz linewidth for cesium-based quantum information processing

A single-photon source with narrow bandwidth,high purity,and large brightness can efficiently interact with material qubits strongly coupled to an optical microcavity for quantum information processing.Here,we experimentally demonstrate a degenerate doubly resonant single-photon source at 852 nm by the cavity-enhanced spontaneous parametric downconversion process with a 100%duty cycle of generation.The single photon source possesses both high purity with a second-order correlation g^((2))_(h)(0)=0.021 and narrow linewidth with△_(V_(sp))=(800±13)kHz.The single-photon s Single-photon source with sub-MHz linewidth for cesium-based quantum information processingource is compatible with the cesium atom D2 line and can be used for cesium-based quantum information processing Single-photon source with sub-MHz linewidth for cesium-based quantum information processing0.021.

某院住院患者多重耐药鲍曼不动杆菌耐药性及耐药基因检测分析

目的:分析许昌市中心医院住院患者多重耐药鲍曼不动杆菌(MDR-Ab)耐药性及耐药基因检测结果。方法:选取2021年2月—2024年2月许昌市中心医院住院患者标本中分离出的112株MDR-Ab,分析MDR-Ab对常见抗菌药物的耐药性及耐药基因检测结果。结果:MDR-Ab对头孢吡肟、头孢他啶、头孢噻肟、环丙沙星的耐药率为100%;对氨苄青霉素舒巴坦、阿米卡星、庆大霉素、左氧氟沙星、四环素、头孢哌酮舒巴坦的耐药率高于80%;对亚胺培南、美罗培南的耐药率高于50%;对米诺环素、替加环素、多粘菌素B1的耐药率较低,均低于20%。112株MDR-Ab内检出D类酶耐药基因car O、ade B、OXA-51基因均为112株,OXA-23基因106株;β-内酰胺酶(A类)耐药基因中TEM 112株,PER基因29株;消毒剂耐药基因qac E 60株;氨基糖苷类耐药基因Arm A 88株。112株MDR-Ab均携带多种耐药相关基因,car O、TEM、OXA-51、ade B为100%携带基因;另携带Arm A+OXA-23+qac E基因占比最高(40.07%),其次为携带PER+Arm A+OXA-23+qac E基因(20.54%)。结论:MDR-Ab携带多种耐药基因,主要为car O、ade B、OXA-51、TEM基因,对各类抗菌药物的耐药率有差异,临床用药前需加强药敏试验并检测耐药基因。