Supramolecular polymer-based gel fracturing fluid with a double network applied in ultra-deep hydraulic fracturing

A gel based on polyacrylamide,exhibiting delayed crosslinking characteristics,emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong wellbores.High viscosity/viscoelasticity of the fracturing fluid was required to maintain excellent proppant suspension properties before gelling.Taking into account both the cost and the potential damage to reservoirs,polymers with lower concentrations and molecular weights are generally preferred.In this work,the supramolecular action was integrated into the polymer,resulting in significant increases in the viscosity and viscoelasticity of the synthesized supramolecular polymer system.The double network gel,which is formed by the combination of the supramolecular polymer system and a small quantity of Zr-crosslinker,effectively resists temperature while minimizing permeability damage to the reservoir.The results indicate that the supramolecular polymer system with a molecular weight of(268—380)×10^(4)g/mol can achieve the same viscosity and viscoelasticity at 0.4 wt%due to the supramolecular interaction between polymers,compared to the 0.6 wt%traditional polymer(hydrolyzed polyacrylamide,molecular weight of 1078×10^(4)g/mol).The supramolecular polymer system possessed excellent proppant suspension properties with a 0.55 cm/min sedimentation rate at 0.4 wt%,whereas the0.6 wt%traditional polymer had a rate of 0.57 cm/min.In comparison to the traditional gel with a Zrcrosslinker concentration of 0.6 wt%and an elastic modulus of 7.77 Pa,the double network gel with a higher elastic modulus(9.00 Pa)could be formed only at 0.1 wt%Zr-crosslinker,which greatly reduced the amount of residue of the fluid after gel-breaking.The viscosity of the double network gel was66 m Pa s after 2 h shearing,whereas the traditional gel only reached 27 m Pa s.

Adhesion property of AlCrNbSiTi high-entropy alloy coating on zirconium:experimental and theoretical studies

Experimental scratch tests and first-principles calculations were used to investigate the adhesion property of AlCrNbSiTi high-entropy alloy(HEA)coatings on zirconium substrates.AlCrNbSiTi HEA and Cr coatings were deposited on Zr alloy substrates using multi-arc ion plating technology,and scratch tests were subsequently conducted to estimate the adhesion property of the coatings.The results indicated that Cr coatings had better adhesion strength than HEA coatings,and the HEA coatings showed brittleness.The special quasi-random structure approach was used to build HEA models,and Cr/Zr and HEA/Zr interface models were employed to investigate the cohesion between the coatings and Zr substrate using first-principles calculations.The calculated interface energies showed that the cohesion between the Cr coating and the Zr substrate was stronger than that of the HEA coating with Zr.In contrary to Al or Si in the HEA coating,Cr,Nb,and Ti atoms binded strongly with Zr substrate.Based on the calculated elastic constants,it was found that low Cr and high Al content decreased the mechanical performances of HEA coatings.Finally,this study demonstrated the utilization of a combined approach involving first-principles calculations and experimental studies for future HEA coating development.

Multi-Label Image Classification Based on Object Detection and Dynamic Graph Convolutional Networks

Multi-label image classification is recognized as an important task within the field of computer vision,a discipline that has experienced a significant escalation in research endeavors in recent years.The widespread adoption of convolutional neural networks(CNNs)has catalyzed the remarkable success of architectures such as ResNet-101 within the domain of image classification.However,inmulti-label image classification tasks,it is crucial to consider the correlation between labels.In order to improve the accuracy and performance of multi-label classification and fully combine visual and semantic features,many existing studies use graph convolutional networks(GCN)for modeling.Object detection and multi-label image classification exhibit a degree of conceptual overlap;however,the integration of these two tasks within a unified framework has been relatively underexplored in the existing literature.In this paper,we come up with Object-GCN framework,a model combining object detection network YOLOv5 and graph convolutional network,and we carry out a thorough experimental analysis using a range of well-established public datasets.The designed framework Object-GCN achieves significantly better performance than existing studies in public datasets COCO2014,VOC2007,VOC2012.The final results achieved are 86.9%,96.7%,and 96.3%mean Average Precision(mAP)across the three datasets.

Fermi Surface Nesting with Heavy Quasiparticles in the Locally Noncentrosymmetric Superconductor CeRh2As2

The locally noncentrosymmetric heavy fermion superconductor CeRh2As2 has attracted considerable interests due to its rich superconducting phases,accompanied by possible quadrupole density wave and pronounced antiferromagnetic excitations.To understand the underlying physics,here we report measurements from highresolution angle-resolved photoemission.Our results reveal fine splittings of the conduction bands related to the locally noncentrosymmetric structure,as well as a quasi-two-dimensional Fermi surface(FS)with strong 4𝑓contributions.The FS shows signs of nesting with an in-plane vector q1=(π/α,π/α),which is facilitated by the heavy bands nearˉ𝑋arising from the characteristic conduction-X hybridization.The FS nesting provides a natural explanation for the observed antiferromagnetic spin fluctuations at(π/α,π/α),which might be the driving force for its unconventional superconductivity.Our experimental results can be reasonably explained by density functional theory plus dynamical mean field theory calculations,which can capture the strong correlation effects.Our study not only provides spectroscopic signature of the key factors underlying the field-induced superconducting transition,but also uncovers the critical role of FS nesting and lattice Kondo effect in the underlying magnetic fluctuations.

Cases Report of Atypical Aortic Dissection

Background: Aortic dissection (AD) is one of the common causes of fatal chest pain in emergency medicine. The main and most common clinical manifestation is pain, with about 90% of patients experiencing sudden persistent, tearing or cutting-like pain in the chest or back. However, there have also been reports of myocardial infarction, heart failure, renal failure, syncope, shock, stroke, paraplegia and other cases. Clinical misdiagnosis is common. Aim: Alert clinicians to aortic dissection with shock and chest tightness as the main clinical presentations. Case Presentation: Report on two cases of aortic dissection with syncope and shock as the main manifestations. Conclusion: Aortic dissection is a highly dangerous cardiovascular emergency with a high mortality rate. In clinical practice, awareness of the clinical manifestations of aortic dissection should be increased. Careful inquiry about medical history, attention to atypical clinical presentations of aortic dissection, thorough physical examination, and comprehensive diagnostic evaluation can improve the success rate of diagnosing aortic dissection.

A Study on the Pedagogical Application of Chinese New Year Culture in International Chinese Language Education

Culture teaching is an inseparable part of International Chinese Language Education,and it has great significance in international Chinese language teaching.Students can enhance their interest in Chinese language learning and improve their learning effect through understanding the excellent traditional Chinese culture,at the same time,culture teaching can help to disseminate the Chinese culture and promote the development of a multicultural world.Taking the teaching of Chinese New Year culture as an example,we analyze the current teaching materials involving Chinese New Year culture with high popularity and acceptance,put forward effective teaching methods matching the feasibility of teaching Chinese New Year culture,and then present the specific teaching design of Chinese New Year culture,in order to provide references for the teaching of culture in International Chinese Language Education.

老龄化与媒介研究:现代社会转型与学科未来方向

人口老龄化是目前中国社会面对的结构性变化之一。“老龄化与媒介”研究作为跨学科研究领域,需要对新的社会现象作出理论与方法上的回应。本研究通过检视中国在老龄化进程与老年学建设上的位置,提出老龄化问题的社会意涵应该得到更多学术关注,未来研究应该更多采取文化批判视角,对数字媒体、智能技术、平台治理等与老年人的关系加以审视。

Study on Horizontal Well Layout Boundary Considering Wellbore Pressure Loss

Based on the Dikken analytical calculation method of wellbore pressure loss under single-phase fluid and turbulent flow conditions, the correlation model between horizontal well output and horizontal section length and horizontal section distributed pressure difference is constructed. The influence degree of wellbore pressure loss on daily oil production of horizontal well, horizontal section pressure and production effect of horizontal well under different horizontal well lengths is analyzed, which provides certain reference for the design of horizontal well length and well layout.

A translational study of somatosensory evoked potential time–frequency components in rats,goats,and humans

Somatosensory evoked potentials(SEPs)have been widely used to assess neurological function in clinical practice.A good understanding of the association between SEP signals and neurological function is helpful for precise diagnosis of impairment location.Previous studies on SEPs have been reported in animal models.However,few studies have reported the relationships between SEP waveforms in animals and those in humans.In this study,we collected normal SEP waveforms and decomposed them into specific time–frequency components(TFCs).Our results showed three stable TFC distribution regions in intact goats and rats and in humans.After we induced spinal cord injury in the animal models,a greater number of small TFC distribution regions were observed in the injured goat and rat groups than in the normal group.Moreover,there were significant correlations(P<0.05)and linear relationships between the main SEP TFCs of the human group and those of the goat and rat groups.A stable TFC distribution of SEP components was observed in the human,goat and rat groups,and the TFC distribution modes were similar between the three groups.Results in various animal models in this study could be translated to future clinical studies based on SEP TFC analysis.Human studies were approved by the Institutional Review Board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster(approval No.UM 05-312 T/975)on December 5,2005.Rat experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of Li Ka Shing Faculty of Medicine of the University of Hong Kong(approval No.CULART 2912-12)on January 28,2013.Goat experiments were approved by the Animal Ethics Committee of Affiliated Hospital of Guangdong Medical University(approval No.GDY2002132)on March 5,2018.

基于1 m尺度甲醇油池火模拟计算的不同辐射模型数值评估研究

池火是火灾灾害中最常遇到的火焰类型之一,发展油池火的精细化建模有利于液体火灾事故危害性的精准分析及评估。众所周知,热辐射建模是准确模拟各种火灾场景的关键环节。因此,为建立合适的辐射模型,在这项工作中,通过将四个不同的辐射模型耦合到开源火灾模拟代码FDS中,并使用有限体积法求解辐射强度传输方程,对大尺度甲醇池火开展了LES仿真研究。结合NIST的实验数据,对不同辐射模型的影响特性及结果进行了对比分析。关于温度计算,基于WSGG的辐射模型和Cassol的模型表现更好。此外,所有模型都能很好地预测脉动频率。然而,关于辐射热通量的预测,Cassol的两个模型和FDS默认模型的表现优于其他模型,获得每个组分的准确光谱信息数据和确定混合气体的WSGG系数的方法是成功预测火焰辐射的重要因素。

Stereotactic body radiotherapy combined with sintilimab in patients with recurrent or oligometastatic hepatocellular carcinoma: A phase Ⅱ clinical trial

BACKGROUND Stereotactic body radiotherapy(SBRT)and programmed cell death 1 inhibitors have shown potential in treating hepatocellular carcinoma(HCC)in retrospective studies.AIM To evaluate the efficacy of combining SBRT with sintilimab for patients with recurrent or oligometastatic HCC.METHODS This trial involved patients with recurrent or oligometastatic HCC intravenously treated with SBRT plus sintilimab every 3 wk for 12 mo or until disease progression.The primary endpoint was progression-free survival(PFS).RESULTS Twenty-five patients were enrolled from August 14,2019,to August 23,2021.The median treatment duration was 10.2(range,0.7-14.6)months.SBRT was delivered at a median dose of 54(range,48-60)Gy in 6(range,6-10)fractions.The median follow-up time was 21.9(range,10.3-39.7)mo,and 32 targeted lesions among 25 patients were evaluated for treatment response according to the Response Evaluation Criteria in Solid Tumors version 1.1.The median PFS was 19.7 mo[95%confidence interval(CI):16.9-NA],with PFS rates of 68%(95%CI:52-89)and 45.3%(95%CI:28-73.4)at 12 and 24 mo,respectively.The median overall survival(OS)was not reached,with OS rates of 91.5%(95%CI:80.8-100.0)and 83.2%(95%CI:66.5-100.0)at 12 and 24 mo,respectively.The 1-and 2-year local control rate were 100%and 90.9%(95%CI:75.4%-100.0%),respectively.The confirmed objective response rate and disease control rate was 96%,and 96%,respectively.Most adverse events were graded as 1 or 2,and grade 3 adverse events were observed in three patients.CONCLUSION SBRT plus sintilimab is an effective,well-tolerated treatment regimen for patients with recurrent or oligometastatic HCC.

Nanomedicine-boosting icaritin-based immunotherapy of advanced hepatocellular carcinoma

Traditional treatments for advanced hepatocellular carcinoma(HCC),such as surgical resection,transplantation,radiofrequency ablation,and chemotherapy are unsatisfactory,and therefore the exploration of powerful therapeutic strategies is urgently needed.Immunotherapy has emerged as a promising strategy for advanced HCC treatment due to its minimal side effects and long-lasting therapeutic memory effects.Recent studies have demonstrated that icaritin could serve as an immunomodulator for effective immunotherapy of advanced HCC.Encouragingly,in 2022,icaritin soft capsules were approved by the National Medical Products Administration(NMPA)of China for the immunotherapy of advanced HCC.However,the therapeutic efficacy of icaritin in clinical practice is impaired by its poor bioavailability and unfavorable in vivo delivery efficiency.Recently,functionalized drug delivery systems including stimuli-responsive nanocarriers,cell membrane-coated nanocarriers,and living cell-nanocarrier systems have been designed to overcome the shortcomings of drugs,including the low bioavailability and limited delivery efficiency as well as side effects.Taken together,the development of icaritin-based nanomedicines is expected to further improve the immunotherapy of advanced HCC.Herein,we compared the different preparation methods for icaritin,interpreted the HCC immune microenvironment and the mechanisms underlying icaritin for treatment of advanced HCC,and discussed both the design of icaritin-based nanomedicines with high icaritin loading and the latest progress in icaritinbased nanomedicines for advanced HCC immunotherapy.Finally,the prospects to promote further clinical translation of icaritin-based nanomedicines for the immunotherapy of advanced HCC were proposed.

Identification of injury type using somatosensory and motor evoked potentials in a rat spinal cord injury model

The spinal cord is at risk of injury during spinal surgery.If intraoperative spinal co rd injury is identified early,irreve rsible impairment or loss of neurological function can be prevented.Different types of spinal cord injury result in damage to diffe rent spinal cord regions,which may cause diffe rent somatosensory and motor evoked potential signal res ponses.In this study,we examined electrophysiological and histopathological changes between contusion,distra ction,and dislocation spinal cord injuries in a rat model.We found that contusion led to the most severe dorsal white matter injury and caused considerable attenuation of both somatosensory and motor evoked potentials.Dislocation resulted in loss of myelinated axons in the lateral region of the injured spinal cord along the rostrocaudal axis.The amplitude of attenuation in motor evoked potential responses caused by dislocation was greater than that caused by contusion.After distraction injury,extracellular spaces were slightly but not significantly enlarged;somatosensory evoked potential res ponses slightly decreased and motor evoked potential responses were lost.Correlation analysis showed that histological and electrophysiological findings we re significantly correlated and related to injury type.Intraope rative monitoring of both somatosensory and motor evoked potentials has the potential to identify iatrogenic spinal cord injury type during surgery.

Magnetic Damping Properties of Single-Crystalline Co_(55)Mn_(18)Ga_(27) and Co_(50)Mn_(18)Ga_(32) Films

We investigate the structural,static magnetic and damping properties in two Mn-deficient magnetic Weyl semimetal Co-Mn-Ga(CMG) alloy films,i.e.,Co_(55)Mn_(18)Ga_(27)(CMG1) and Co_(50)Mn_(18)Ga_(32)(CMG2),which were epitaxially grown on MgO(001) substrates.CMG1 has a mixing phase of B2and L21,larger saturation magnetization(M_(s) ~760 emu/cm^(3)),stronger in-plane magnetic anisotropy.CMG2 has an almost pure B2phase,smaller M_(s)(~330 emu/cm^(3)),negligible in-plane magnetic anisotropy.Time-resolved magneto-optical Kerr effect results unambiguously demonstrate an obvious perpendicular standing spin wave(PSSW) mode in addition to the Kittel mode for both of the CMG films.The intrinsic damping constant is about 0.0055 and 0.015 for CMG1 and CMG2,respectively,which are both significantly larger than that of the stoichiometric CMG(i.e.,Co_(2)MnGa)film reported previously.In combination with the first-principles calculations,the intrinsic damping properties of the Mn-deficient CMG films can be well explained by considering the increase of density of states at the Fermi level,reduction of M_(s),and excitation of the PSSW mode.These findings provide a new clue to tuning the magnetic damping of the magnetic Weyl semimetal film through slight off-stoichiometry.

袋型阻尼密封动力特性数值与实验研究

通过非定常动网格技术,建立了袋型阻尼密封动力特性多频椭圆涡动求解模型,在实验验证求解模型准确性的基础上,研究了袋型阻尼密封腔室轴向长度、周向挡板数量及深度对密封动力特性的影响;并对不同周向挡板数量的等腔室袋型阻尼密封的泄漏特性进行实验研究。研究发现,密封腔室轴向长度为d=4/8mm的传统袋型阻尼密封比d=10mm的等腔室袋型阻尼密封的有效阻尼Ceff约增加21.5%;随着二次腔室轴向长度从d=10mm减小到d=6mm,有效阻尼Ceff约增加14.1%,流体压缩效应更加明显,增加了腔室内的动压,有利于抑制转子涡动。等腔室袋型阻尼密封的周向档板数量对其阻尼系数有显著影响,当涡动频率大于200Hz时,挡板数从24减少到4时,有效阻尼Ceff约增加37.8%,稳定性明显提高。当袋型阻尼密封空腔深度从3mm增加到6mm时,等腔室袋型阻尼密封的交叉刚度较大、Ceff约减小51.7%,稳定性降低。

关节镜下可调节袢钢板全内技术重建前交叉韧带的临床疗效分析

目的探讨关节镜下可调节袢钢板全内技术重建前交叉韧带(ACL)的临床疗效。方法回顾性分析2018年1月-2019年7月湖南省人民医院集团澧县人民医院21例ACL损伤患者的临床资料,均行关节镜下可调节袢全内技术ACL重建。其中,男13例,女8例,年龄41~56岁,平均46岁,Lachman试验Ⅲ度阳性伴软性终止点18例,Lachman试验Ⅱ度阳性伴硬性终止点3例。观察移植物粗细、术前及术后影像学、术前及术后Lachman试验情况,比较术后健侧与患侧屈膝活动度以及术前、术后半年及术后2年的国际膝关节文献委员会(IKDC)评分、Lysholm评分和Larson评分等指标,以综合评估临床疗效。结果21例患者随访时间24个月。术前Lachman试验Ⅲ度阳性伴软性终止点和LachmanⅡ度阳性伴硬性终止点的病例,术中均证实ACL完全或大部分断裂。术后半年Lachman试验阳性0例,阴性21例。术中所使用的移植物平均直径(8.59±0.44)mm,术后三维CT测量股骨粗骨道长度(21.66±2.51)mm,移植物进入股骨骨道长度(19.82±2.29)mm,胫骨粗骨道长度(19.67±1.02)mm,移植物进入胫骨骨道长度(17.69±1.26)mm。术后半年MRI显示:移植物固定牢靠,与骨道贴合良好,信号均匀。术后末次随访,健侧、患侧最大屈膝角度分别为(131.42±3.59)°和(130.71±3.64)°,两者比较,差异无统计学意义(P>0.05)。术后半年Lysholm评分、IKDC评分和Larson评分分别为(88.19±1.97)、(74.05±2.36)和(67.52±2.23)分,术后2年分别为(97.76±1.97)、(88.62±3.07)和(90.57±2.46)分,均较术前的(22.00±3.35)、(41.67±1.85)和(39.81±1.81)分明显提高,术后半年和术后2年分别与术前比较,差异均有统计学意义(P<0.05)。结论关节镜下可调节袢钢板全内技术重建ACL,肌腱利用率高,稳定性好,中远期膝关节功能恢复满意,疗效肯定。

一种联轴器动力学简化计算方法与验证

为快速得到联轴器的固有频率,采用结构动力学理论简化联轴器计算模型,得到一阶弯曲固有频率理论计算方法。采用三维有限元分析方法进行联轴器的模态分析,并针对理论和有限元计算结果进行比对核算。该理论方法仅需少量的结构参数便可快速获得联轴器的一阶弯曲固有频率值。后续又分别针对11款联轴器进行分析与比对,发现当联轴器中段长径比大于3、中段长度占比大于60%、中段质量占比大于50%的联轴器,用该理论方法的计算偏差一般能控制在15%以内,能够较好的应对快速计算的需求。

脓毒血症小鼠致肺损伤模型的研究

目的:探讨盲肠结扎穿刺建造的脓毒血症小鼠模型中肺组织损伤的相关机制。方法:选取42只C57BL/6雄性小鼠,随机分为正常对照组、假手术组及脓毒血症组,各14只。正常对照组不做处理,假手术组行盲肠结扎,脓毒血症组予以盲肠结扎穿刺。24 h收集各组肺组织,观察脓毒血症情况评分(MSS)、生存率、肺组织形态改变情况、肺组织损伤评分、中性粒细胞以及肺组织中炎症因子肿瘤坏死因子α(TNF-α)和白细胞介素(IL)-6表达水平的差异。结果:脓毒血症组MSS评分、肺损伤评分、中性粒细胞数、TNF-α及IL-6表达水平均较正常对照组、假手术组升高(P<0.01)。结论:脓毒血症可造成病理学层面的小鼠肺组织损伤,致炎症因子表达升高,降低小鼠的生存率。通过观察该模型中反映肺损伤程度的相关指标的变化,可评估脓毒血症严重程度和研究损伤相关机制。

Deferoxamine promotes recovery of traumatic spinal cord injury by inhibiting ferroptosis

Ferroptosis is an iron-dependent novel cell death pathway. Deferoxamine, a ferroptosis inhibitor, has been reported to promote spinal cord injury repair. It has yet to be clarified whether ferroptosis inhibition represents the mechanism of action of Deferoxamine on spinal cord injury recovery. A rat model of Deferoxamine at thoracic 10 segment was established using a modified Allen's method. Ninety 8-week-old female Wistar rats were used. Rats in the Deferoxamine group were intraperitoneally injected with 100 mg/kg Deferoxamine 30 minutes before injury. Simultaneously, the Sham and Deferoxamine groups served as controls. Drug administration was conducted for 7 consecutive days. The results were as follows:(1) Electron microscopy revealed shrunken mitochondria in the spinal cord injury group.(2) The Basso, Beattie and Bresnahan locomotor rating score showed that recovery of the hindlimb was remarkably better in the Deferoxamine group than in the spinal cord injury group.(3) The iron concentration was lower in the Deferoxamine group than in the spinal cord injury group after injury.(4) Western blot assay revealed that, compared with the spinal cord injury group, GPX4, xCT, and glutathione expression was markedly increased in the Deferoxamine group.(5) Real-time polymerase chain reaction revealed that, compared with the Deferoxamine group, mRNA levels of ferroptosis-related genes Acyl-CoA synthetase family member 2(ACSF2) and iron-responsive element-binding protein 2(IREB2) were up-regulated in the Deferoxamine group.(6) Deferoxamine increased survival of neurons and inhibited gliosis. These findings confirm that Deferoxamine can repair spinal cord injury by inhibiting ferroptosis. Targeting ferroptosis is therefore a promising therapeutic approach for spinal cord injury.

Effect of Zr content on crack formation and mechanical properties of IN738LC processed by selective laser melting

Two batches of commercial IN738LC alloy powders with different Zr contents were printed under the same parameters.The influences of Zr content(0.024 wt.% and 0.12 wt.%,respectively) in powders on crack density,distribution,formation mechanism and mechanical properties of selective laser melting(SLM)-treated parts were systematically studied.It was found that the crack density(area ratio) increases from 0.15% to 0.87% in the XOY plane and from 0.21% to 1.81% in the XOZ plane along with the Zr content increase from 0.024 wt.% to 0.12 wt.% in the original powders.Solidification cracks are formed along the epitaxially grown <001>-oriented columnar grain boundaries in molten pool center.The ultimate tensile strength of Sample 1(0.024 wt.% Zr) is 1113 MPa,and there are dimples in tensile fracture.With an increase in the Zr content to 0.12 wt.%(Sample 2),the ultimate tensile strength of Sample 2 decreases to 610 MPa,and there are numerous original cracks and exposed columnar grain boundaries in tensile fracture.The optimization of printing parameters of Sample 2 considerably increases the ultimate tensile strength by 55.2% to 947 MPa,and the plasticity is greatly improved.