Theoretical and numerical investigations on the headspace of cartridge cases considering axial deformation and movement

The cartridge case headspace is the axial clearance between the cartridge and bolt of an automatic weapon,and influences the reliability and security of the weapon.Accordingly,theoretical and numerical studies were conducted to analyze the dynamic response of cartridge cases during internal impact considering the initial radial clearances between the cartridge case and chamber.A theoretical model was proposed to predict the cartridge case headspace considering both the deformation and movement of the cartridge case and confirmed by the results of nonlinear finite element simulations.The differences between the results of the conventional static model and the dynamic model were then comprehensively evaluated.The effects of the angle between the cartridge and chamber,the cartridge case material,and the intermal impact pressure on the predicted headspace value were also analyzed.The dynamic response of the cartridge case predicted by the dynamic model was more accurate than that predicted by the conventional static model.The internal impact pressure,pressure change rate,and cartridge material were all found to affect the predicted headspace.

A novel algorithm for evaluating cement azimuthal density based on perturbation theory in horizontal well

Cement density monitoring plays a vital role in evaluating the quality of cementing projects,which is of great significance to the development of oil and gas.However,the presence of inhomogeneous cement distribution and casing eccentricity in horizontal wells often complicates the accurate evaluation of cement azimuthal density.In this regard,this paper proposes an algorithm to calculate the cement azimuthal density in horizontal wells using a multi-detector gamma-ray detection system.The spatial dynamic response functions are simulated to obtain the influence of cement density on gamma-ray counts by the perturbation theory,and the contribution of cement density in six sectors to the gamma-ray recorded by different detectors is obtained by integrating the spatial dynamic response functions.Combined with the relationship between gamma-ray counts and cement density,a multi-parameter calculation equation system is established,and the regularized Newton iteration method is employed to invert casing eccentricity and cement azimuthal density.This approach ensures the stability of the inversion process while simultaneously achieving an accuracy of 0.05 g/cm^(3) for the cement azimuthal density.This accuracy level is ten times higher compared to density accuracy calculated using calibration equations.Overall,this algorithm enhances the accuracy of cement azimuthal density evaluation,provides valuable technical support for the monitoring of cement azimuthal density in the oil and gas industry.

Cryoablation for intrapulmonary bronchial cyst:A case report

BACKGROUND Bronchial cysts are congenital malformations usually located in the mediastinum,and intrapulmonary localization is very rare.Cryoablation is a novel therapeutic approach that promotes tumor necrosis and stimulates anti-tumor immune responses.CASE SUMMARY This article reports a case of a 68-year-old male patient who was diagnosed with an intrapulmonary bronchogenic cyst by computed tomography examination and pathology,and the patient subsequently underwent cryoablation therapy and achieved complete response with after 3 months of follow-up.CONCLUSION Intrapulmonary bronchogenic cysts are very rare,cryoablation therapy is feasible,safe,and effective for intrapulmonary bronchial cysts.

Complete response of gallbladder cancer treated with gemcitabine and cisplatin chemotherapy combined with durvalumab:A case report and review of literature

BACKGROUND Gallbladder cancer(GBC)is the most common and aggressive subtype of biliary tract cancer(BTC)and has a poor prognosis.A newly developed regimen of gemcitabine,cisplatin,and durvalumab shows promise for the treatment of advanced BTC.However,the efficacy of this treatment for GBC remains unclear.CASE SUMMARY In this report,we present a case in which the triple-drug regimen exhibited marked effectiveness in treating locally advanced GBC,thus leading to a long-term survival benefit.A 68-year-old man was diagnosed with locally advanced GBC,which rendered him ineligible for curative surgery.Following three cycles of therapy,a partial response was observed.After one year of combined therapy,a clinical complete response was successfully achieved.Subsequent maintenance therapy with durvalumab monotherapy resulted in a disease-free survival of 9 months for the patient.The patient experienced tolerable toxicities of reversible grade 2 nausea and fatigue.Tolerable adverse events were observed in the patient throughout the entirety of the treatment.CONCLUSION The combination of gemcitabine and cisplatin chemotherapy with durvalumab was proven to be an effective treatment approach for advanced GBC,with manageable adverse events.Further research is warranted to substantiate the effectiveness of the combined regimen in the context of GBC.

Irreversible electroporation for liver metastasis from pancreatic cancer: A case report

BACKGROUND Pancreatic cancer has a poor prognosis;40%–50% of patients have liver metastases at the time of initial diagnosis and only 15%–20% undergo surgical resection. Irreversible electroporation(IRE) is a new, non-thermal local ablation method for solid tumors, which can induce cell membrane permeabilization,resulting in unrecoverable nanoscale perforation and apoptotic cell death without damaging the structural components of tissues.CASE SUMMARY We report the case of a 66-year-old female patient with liver metastasis from pancreatic cancer with a pathological diagnosis of poorly differentiated adenocarcinoma. Carbohydrate antigen 19-9 was elevated to 420.3 U/m L.Computed tomography showed a pancreas mass of 2.7 cm × 2.5 cm and single liver metastasis of 1.4 cm × 1.1 cm in the S6 area. The patient underwent IRE and arterial infusion chemotherapy and received tegafur. The therapeutic effect of the combination treatment has been evaluated as complete response. To date, the patient has survived for > 12 mo and is receiving tegafur as maintenance therapy(at the time this case report was written).CONCLUSION IRE plus arterial infusion chemotherapy and tegafur may be synergistic,providing a reference for treating liver metastasis from pancreatic cancer.

Extensive adhesion formation in a total knee replacement in the setting of a gastrointestinal stromal tumor:A case report

BACKGROUND Gastrointestinal stromal tumors(GISTs)are rare primary neoplasms of the gastrointestinal tract,accounting for 1%to 2%of all gastrointestinal neoplasms worldwide.GISTs are frequently discovered incidentally during workup for other diagnosis or intestinal obstruction,as they can present with few or no symptoms.Simultaneously,GISTs confer a high degree of malignant transformation,with a progression in about 10%to 30%of cases.CASE SUMMARY A 63-year-old healthy female presented to our institution with complaints of right knee pain and limited passive and active motion in the setting of a previous right total knee arthroplasty(TKA).One year after TKA,the patient was incidentally diagnosed with a GIST,which was successfully removed.After removal,the patient continued to have limited range of motion of the right knee and subsequently underwent revision TKA.Intraoperatively significant fibrotic adhesions were found encapsulating the femoral and tibial components.The patient’s pain improved postoperatively,however,she continued to have decreased range of motion with difficulty ambulating.CONCLUSION We propose that this case may demonstrate a proinflammatory milieu arising from a GIST,which had a direct influence on the outcome of recent total knee arthroplasty.This proposed mechanism between neoplastic cytokinetic activity and adhesion formation could have implications on preoperative and postoperative orthopedic management of total knee arthroplasty.

Lenvatinib for large hepatocellular carcinomas with portal trunk invasion:Two case reports

BACKGROUND In a phase III trial of lenvatinib as first-line treatment for advanced unresectable hepatocellular carcinoma(uHCC),the drug proved non-inferior to sorafenib in terms of the overall survival,but offered better progression-free survival.However,the effects of lenvatinib in uHCC patients with a tumor thrombus in the main portal vein and/or a high tumor burden(tumor occupancy more than 50%of the total liver volume),remain unclear,because these were set as exclusion criteria in the aforementioned trial.CASE SUMMARY A 53-year-old man(case 1)and 66-year-old woman(case 2)with uHCC presented to us with a tumor thrombus in both the main portal vein and inferior vena cava,a high tumor burden accompanied by a tumor diameter greater than>100 mm,and distant metastasis,with the residual liver function classified as grade 2A according to the modified Albumin–Bilirubin grading.We started both patients on lenvatinib.The therapeutic effect,as evaluated by the modified Response Evaluation Criteria in Solid Tumors,was rated as partial response in both case 1 and case 2(at 8 wk and 4 wk after the start of lenvatinib administration,respectively).The therapeutic effect was sustained for 6 mo in case 1 and 20 mo in case 2.Fever occurred as an adverse event in both case 1 and 2,and hyperthyroidism and thrombocytopenia in only case 2,neither of which,however,necessitated treatment discontinuation.CONCLUSION Even in hepatocellular carcinoma patients with poor prognostic factors,if the liver function is well-preserved,lenvatinib is effective and safe.

Thin bed responses and correction methods for cased hole density logging

The study of the thin bed responses and correction methods in cased hole density logging can provide a theoretical basis for research to improve data processing methods. By using the Monte Carlo program MCNP, the change of detector count from thin beds with the vertical depth was calculated at different casing thicknesses. The calculation showed that with the low density thin bed moving upward, detector count first increased to a maximum then decreased. The responses of a thin bed with a high density were opposite to those of a thin bed with a low density. The change curve was symmetrical, and the maximums or minimums appeared at the midpoint between the detector and source. Besides, detector count increased with increasing thin bed thickness. At a specific thin bed thickness, further increase of thin bed thickness resulted in a slow increase of detector count then the count rate leveled off. In actual logging, the influence of adjacent formations on density log measurements can be ignored. Finally, based on numerical simulation correction methods for the dual influence of casing and thin beds are discussed.

Conversion immunotherapy for deficient mismatch repair locally unresectable colon cancer:A case report

BACKGROUND Owing to the special features of biologics,deficient mismatch repair(dMMR)in patients with colon cancer has achieved little treatment efficacy from chemoradiotherapy.Immunotherapy has shown promising results for the treatment of colon cancer.The high response rate observed suggests a great option for patients presenting with unresectable tumors,as it allows for better oncological resection.Here,we aimed to highlight the significant effects of immunotherapy on dMMR in colon cancer.CASE SUMMARY A 54-year-old man diagnosed with locally unresectable dMMR colon cancer received preoperative immunotherapy(three cycles of pembrolizumab)and achieved a pathological complete response after surgery.CONCLUSION Immunotherapy can be used as a conversion treatment for locally unresectable colon cancer with dMMR.

Successful multidisciplinary therapy for a patient with liver metastasis from ascending colon adenocarcinoma:A case report and review of literature

BACKGROUND Liver metastasis is the most common form of distant metastasis in colorectal cancer,and the only possible curative treatment for patients with colorectal liver metastases(CRLM)is hepatectomy.However,approximately 25%of patients with CRLM have indications for liver resection at the initial diagnosis.Strategies aimed at downstaging large or multifocal tumors to enable curative resection are appealing.CASE SUMMARY A 42-year-old man was diagnosed with ascending colon cancer and liver metastases.Due to the huge lesion size and compression of the right portal vein,the liver metastases were initially diagnosed as unresectable lesions.The patient was treated with preoperative transcatheter arterial chemoembolization(TACE)consisting of 5-fluorouracil/Leucovorin/oxaliplatin/Endostar®.After four courses,radical right-sided colectomy and ileum transverse colon anastomosis were performed.Postoperatively,the pathological analysis revealed moderately differentiated adenocarcinoma with necrosis and negative margins.Thereafter,S7/S8 partial hepatectomy was performed after two courses of neoadjuvant chemotherapy.Pathological examination of the resected specimen revealed a pathologically complete response(pCR).Intrahepatic recurrence was detected more than two months after the operation,and the patient was then treated with TACE consisting of irinotecan/Leucovorin/fluorouracil therapy plus Endostar®.Subsequently,the patient was treated with aγ-knife to enhance local control.Notably,a pCR was reached,and the patient's overall survival time was>9 years.CONCLUSION Multidisciplinary treatment can promote the conversion of initially unresectable colorectal liver metastasis and facilitate complete pathological remission of liver lesions.

Temporal pattern of humoral immune response in mild cases of COVID-19

BACKGROUND Understanding the humoral response pattern of coronavirus disease 2019(COVID-19)is one of the essential factors to better characterize the immune memory of patients,which allows understanding the temporality of reinfection,provides answers about the efficacy and durability of protection against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),and consequently helps in global public health and vaccination strategy.Among the patients who became infected with SARS-CoV-2,the majority who did not progress to death were those who developed the mild COVID-19,so understanding the pattern and temporality of the antibody response of these patients is certainly relevant.AIM To investigate the temporal pattern of humoral response of specific immunoglobulin G(IgG)in mild cases of COVID-19.METHODS Blood samples from 191 COVID-19 real-time reverse transcriptase-polymerase chain reaction(RT-qPCR)-positive volunteers from the municipality of Toledo/Paraná/Brazil,underwent two distinct serological tests,enzyme-linked immunosorbent assay,and detection of anti-nucleocapsid IgG.Blood samples and clinicoepidemiological data of the volunteers were collected between November 2020 and February 2021.All assays were performed in duplicate and the manufacturers'recommendations were strictly followed.The data were statistically analyzed using multiple logistic regression;the variables were selected by applying the P<0.05 criterion.RESULTS Serological tests to detect specific IgG were performed on serum samples from volunteers who were diagnosed as being positive by RT-qPCR for COVID-19 or had disease onset in the time interval from less than 1 mo to 7 mo.The time periods when the highest number of participants with detectable IgG was observed were 1,2 and 3 mo.It was observed that 9.42%of participants no longer had detectable IgG antibodies 1 mo only after being infected with SARS-CoV-2 and 1.57%were also IgG negative at less than 1 mo.At 5 mo,3.14%of volunteers were IgG negative,and at 6 or 7 mo,1 volunteer(0.52%)had no detectable IgG.During the period between diagnosis by RT-qPCR/symptoms onset and the date of collection for the study,no statistical significance was observed for any association analyzed.Moreover,considering the age category between 31 and 59 years as the exposed group,the P value was 0.11 for the category 31 to 59 years and 0.32 for the category 60 years or older,showing that in both age categories there was no association between the pair of variables analyzed.Regarding chronic disease,the exposure group consisted of the participants without any comorbidity,so the P value of 0.07 for the category of those with at least one chronic disease showed no association between the two variables.CONCLUSION A temporal pattern of IgG response was not observed,but it is suggested that immunological memory is weak and there is no association between IgG production and age or chronic disease in mild COVID-19.

气候变化应对类ESG国际商事仲裁:优势、困境与中国进路

随着ESG实践在全球范围内的扩展及各国对其监管的加强,气候变化应对类ESG纠纷层出不穷。与其他争议解决机制相比,国际商事仲裁更加契合此类纠纷的跨国性、技术性和纠纷解决紧迫性的特点。开展气候变化应对类ESG国际商事仲裁符合中国当前国际商事仲裁中心建设、新质生产力发展和“双碳”目标实现的需求。然而,此类仲裁也面临着纠纷可仲裁性受限、当事人仲裁合意欠缺、案件透明度需求与仲裁保密性冲突、案外人加入仲裁程序机制缺失等现实困境。在中国开展此类仲裁实践,虽然同样面临以上部分困境,但已具备理论、制度上的可接受性和实践上的可操作性。在法律层面,可考虑在可仲裁性、第三方资助、仲裁协议效力扩张和友好仲裁等方面进行规制。同时,通过仲裁机构在仲裁规则、保密机制和机构合作方面的创新,以及当事人对仲裁条款一系列问题的审慎把关,积极推动气候变化应对类ESG国际商事仲裁在中国的实践。

Arc-length technique for nonlinear finite element analysis

Nonlinear solution of reinforced concrete structures, particularly complete load-deflection response, requires tracing of the equilibrium path and proper treatment of the limit and bifurcation points. In this regard, ordinary solution techniques lead to instability near the limit points and also have problems in case of snap-through and snap-back. Thus they fail to predict the complete load-displacement response. The arc-length method serves the purpose well in principle, received wide acceptance in finite element analysis, and has been used extensively. However modifications to the basic idea are vital to meet the particular needs of the analysis. This paper reviews some of the recent developments of the method in the last two decades, with particular emphasis on nonlinear finite element analysis of reinforced concrete structures.

双作用液环压缩机壳体型线响应面分析及多目标优化

为探究双作用液环压缩机壳体型线对其内流场及性能的影响机理,采用DFFD参数化方法对多级双作用液环压缩机椭圆形壳体型线进行响应面优化分析,并结合NSGA-II多目标优化方法对吸排气区壳体型线进行协同优化。采用VOF多相流模型对该液环压缩机全流域进行非定常计算,双作用液环泵内相态场、压力场基本呈径向对称分布,吸排气区域及叶轮壳体内流场与单作用液环泵分布规律基本一致,随着级数增大液环内的气相区域逐渐减小。响应面结果表明吸气量的大小主要取决于吸气口始端和末端的壳体型线,当R_(A)值趋于0水平,R_(B)处于低水平时,吸气量趋于最大值。轴功率主要受吸、排气口始端位置壳体型线影响,R_(A),R_(C)值越小,轴功率越小。效率的大小主要取决于吸气口始端和末端的壳体型线,且R_(A)值越大,R_(B)值越小,效率越高。在额定出口压比条件下,以吸气量和效率作为优化目标对液环压缩机进行NSGA-II多目标优化,获得其Pareto前沿的最优效率设计J和和最优流量设计K,J方案流量和效率分别高于原方案1.40%和2.53%,K方案流量和效率分别高于原方案16.4%和0.61%。

金州台水准与地下水位响应性对比分析

以地下水作为加卸载动力,对每年地下水位上升与下降期间,金州台水准高差的响应情况进行对比分析研究。结果表明:当地下水位在覆盖层内变化时,水准与水位相关性较高;当地下水位在基岩层与覆盖层间交替变化或在强风化岩层内变化时,水准与水位相关性一般;但当地下水位在基岩层内变化时,水准与水位相关性则相对较差。

血清γ⁃氨基丁酸、氧化应激与血脂异常的剂量⁃反应关系研究

目的:探讨γ‑氨基丁酸(GABA)、氧化应激指标与血脂异常患病风险的剂量‑反应关系,为预防及改善血脂异常提供参考依据。方法:选择2022年8月~2023年8月于海口市某三甲医院住院的149例血脂异常者为病例组,236例血脂正常者为对照组,通过问卷收集研究对象的基本情况,试剂盒测血清GABA水平、超氧化物歧化酶(SOD)活性、谷胱甘肽过氧化物酶(GSH‑Px)活性和丙二醛(MDA)水平。将GABA和氧化应激指标(SOD、GSH‑Px、MDA)按对照组四分位水平从低到高分为4组(Q1组~Q4组),Logistic回归分析血脂异常的患病风险;Spearman相关系数、广义线性模型和限制性立方样条分析GABA与氧化应激指标的相关性,GABA、氧化应激指标与血脂异常的剂量‑反应关系。结果:调整混杂因素后,Logistic回归显示:与Q1组SOD活性、GSH‑Px活性和MDA水平相比,Q4组血脂异常患病风险分别为OR=0.537[95%CI(0.294~0.980)]、OR=0.400[95%CI(0.213~0.750)]和OR=2.375[95%CI(1.254~4.495)](P<0.05)。GABA水平与SOD、GSH‑Px活性呈正相关,与MDA水平呈负相关(P<0.001)。广义线性模型和限制性立方样条显示:血脂异常患病风险随SOD、GSH‑Px活性增加而降低,随MDA水平增加而上升,为线性剂量‑反应关系(P<0.05)。结论:GABA水平与SOD活性、GSH‑Px活性、MDA水平存在相关性,SOD活性、GSH‑Px活性、MDA水平与血脂异常患病风险存在线性剂量‑反应关系。

600MW汽轮机低压缸动力学特性分析与结构优化

针对某600MW凝汽式汽轮机低压缸盖振较大的问题,从动力学特性理论分析入手,采用三维有限元方法对低压缸结构进行了模态分析,提出了一种与低压转子旋转激振力等效的双向简谐力加载方法,对低压缸的受迫振动响应进行了数值计算;基于计算结果分析,提出了低压缸的结构优化改进方案,并从多角度对所提方案进行了效果评估。结果表明,低压缸的下缸刚度较低导致固有频率落入50Hz附近,以及转子轴承支撑中心距离端板较远导致激励力力矩较大,是低压缸振动较大的主要原因;提出的结构优化方案可提高低压缸的固有频率,使其避开50Hz工作频率,同时也能够有效降低振动响应的幅值。

基于OBE理念的军事海洋学专业学员创新能力提升研究

以成果为导向(OBE)教育理念以预期成果为牵引,逆向设计教学内容,能够有效提升学员学习主观能动性,增强学员实践和创新能力。以军事海洋学“快响”大学生创新项目为抓手,深入贯彻OBE教育理念,通过分析两个军事海洋案例,表明该方法能够有效提升军事海洋学专业学员创新能力。

特高压套管悬挂器不同线型凸缘面密封性能分析与优化设计

针对油田井口密封装置圆形凸缘面存在的密封宽度窄、使用寿命短的问题,设计圆形、椭圆、锥面凸缘线型,并开展不同线型凸缘面的密封性能和使用寿命研究。研究表明,在相同结构尺寸、激发载荷条件下,锥面的密封宽度、结构寿命远远优于圆形、椭圆面,但较长的接触宽度导致锥面接触应力无法满足工况需求。建立以锥形密封环为优化对象的分析模型,通过单因素分析确定各结构参数的灵敏度和取值范围,以上下密封面接触应力为优化目标,得到显著因子与接触应力的一阶、二阶响应模型。优化后的接触应力达到密封要求且分别提高21.7%、8.2%,最大方差仅为曲面的30%,能获得可靠的结构寿命。

资源限制性并行任务固定优先级可调度性分析

异构多核平台的发展,导致并行任务需要执行在具有多样性资源的多核平台上.虽然,并行任务的某个程序片段只能在规定的资源上执行,但是这样操作可以充分利用各类不同资源的特性,达到更加快速节能处理任务的目的.同时,具有资源限制任务的可调度性研究在实时嵌入式系统领域已有一定的研究成果,但是采用的任务模型相对简单,分析方法不够精确.鉴于此,本文对具有资源限制性的并行任务在全局固定优先级调度策略下的可调度性问题进行了研究,基于单并行任务的分析方法提出了基于全局固定优先级调度策略的分析方法.首先,基于分解策略提出了高优先级任务干涉的分析方法.然后,将高优先级任务干涉分析方法和单并行任务提出的路径抽象技术相结合,推导出并行任务的最差响应时间算法.最后,通过仿真实验进行验证所提出的算法在可调度性、精确度层面的性能.实验结果表明,提出的算法在各个参数下的接受率实验符合实验预期,分析时间相对降低,但平均分析时间仍然在离线分析的可接受范围内,提出的算法能够对实时系统并行软件设计提供一定的指导价值.