Simulation of the Production Performances of Horizontal Wells with a Fractured Shale Gas Reservoir

The production performances of a well with a shale gas reservoir displaying a complex fracture network are simulated.In particular,a micro-seismic cloud diagram is used to describe the fracture network,and accordingly,a production model is introduced based on a multi-scale flow mechanism.A finite volume method is then exploited for the integration of the model equations.The effects of apparent permeability,conductivity,Langmuir volume,and bottom hole pressure on gas well production are studied accordingly.The simulation results show that ignoring the micro-scale flow mechanism of the shale gas leads to underestimating the well gas production.It is shown that after ten years of production,the cumulative gas production difference between the two scenarios with and without considering the micro-scale flow mechanisms is 19.5%.The greater the fracture conductivity,the higher the initial gas production of the gas well and the cumulative gas production.The larger the Langmuir volume,the higher the gas production rate and the cumulative gas production.With the reduction of the bottom hole pressure,the cumulative gas production increases,but the growth rate gradually decreases.

玄武岩纤维增强混凝土的力学和透水性能分析

在混凝土制造过程中通过掺入纤维来减缓混凝土受到压力作用,在保持透水性能条件下获得更强的力学性能。将6 mm、12 mm的玄武岩纤维掺入混凝土中,分析不同掺量下混凝土的力学性能和透水性能。结果表明:掺入0.1%长度6 mm玄武岩纤维混凝土相对同龄期试块达到了更高抗压强度;大于0.1%时,抗压强度与纤维加入量呈现相反变化。逐渐延长龄期后,玄武岩纤维混凝土达到了更高抗压强度。保持玄武岩纤维掺量相同下,6 mm比12 mm的玄武岩纤维混凝土达到了更高透水性。加入同样长度的玄武岩纤维时,增大玄武岩纤维含量时,试样孔隙率与透水系数都出现了降低的现象。

A Well Productivity Model for Multi-Layered Marine and Continental Transitional Reservoirs with Complex Fracture Networks

Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.

Optimal operation of Internet Data Center with PV and energy storage type of UPS clusters

With the development of green data centers,a large number of Uninterruptible Power Supply(UPS)resources in Internet Data Center(IDC)are becoming idle assets owing to their low utilization rate.The revitalization of these idle UPS resources is an urgent problem that must be addressed.Based on the energy storage type of the UPS(EUPS)and using renewable sources,a solution for IDCs is proposed in this study.Subsequently,an EUPS cluster classification method based on the concept of shared mechanism niche(CSMN)was proposed to effectively solve the EUPS control problem.Accordingly,the classified EUPS aggregation unit was used to determine the optimal operation of the IDC.An IDC cost minimization optimization model was established,and the Quantum Particle Swarm Optimization(QPSO)algorithm was adopted.Finally,the economy and effectiveness of the three-tier optimization framework and model were verified through three case studies.

玄武岩纤维增强混凝土破坏形态及弯曲韧性研究

为综合评价玄武岩纤维混凝土处于弯曲载荷作用下的变形程度及其韧性与破坏形态特征的影响,重点研究了玄武岩纤维增强混凝土抗弯曲性能,测试了玄武岩纤维不同加入比例引起的弯曲韧性差异性。研究结果表明:不含纤维的混凝土试样到达峰值荷载时发生了裂缝的快速扩展,表现为明显的脆性断裂特征;加入体积分数为0.3%的玄武岩纤维,混凝土表面存在明显纤维,在断裂面部位的纤维与混凝土之间保持紧密连接的状态,侧面区域生成了竖向的细裂纹;逐渐提高玄武岩纤维体积分数后,试样获得了更高的峰值荷载,形成了更饱和的荷载—挠度曲线,达到了优异延展效果,弯曲韧性增长速率变慢。

Superior de/hydrogenation performances of MgH2 catalyzed by 3D flower-like TiO2@C nanostructures

Magnesium hydride has been seen as a potential material for solid state hydrogen storage,but the kinetics and thermodynamics obstacles have hindered its development and application.Three-dimensional flower-like TiO2@C and TiO2 were synthesized as the catalyst for MgH2 system and great catalytic activities are acquired in the hydrogen sorption properties.Experiments also show that the flower-like TiO2@C is superior to flower-like TiO2 in improving the hydrogen storage properties of MgH2.The hydrogen desorption onset and peak temperatures of flower-like TiO2 doped MgH2 is reduced to 199.2℃and 245.4℃,while the primitive MgH2 starts to release hydrogen at 294.6℃and the rapid dehydrogenation temperature is even as high as 362.6℃.The onset and peak temperatures of flower-like TiO2@C doped MgH2 are further reduced to 180.3℃and 233.0℃.The flower-like TiO2@C doped MgH2 composite can release6.0 wt%hydrogen at 250℃within 7 min,and 4.86 wt%hydrogen at 225℃within 60 min,while flowerlike TiO2 doped MgH2 can release 6.0 wt%hydrogen at 250℃within 8 min,and 3.89 wt%hydrogen at225℃within 60 min.Hydrogen absorption kinetics is also improved dramatically.Moreover,compared with primitive MgH2 and the flower-like TiO2 doped MgH2,the activation energy of flower-like TiO2@C doped MgH2 is significantly decreased to 67.10 kJ/mol.All the improvement of hydrogen sorption properties can be ascribed to the flower-like structure and the two-phase coexistence of TiO2 and amorphous carbon.Such phase composition and unique structure are proved to be the critical factor to improve the hydrogen sorption properties of MgH2,which can be considered as the new prospect for improving the kinetics of light-metal hydrogen storage materials.

Combining Serum Procalcitonin Level,Thromboelastography,and Platelet Count to Predict Short-term Development of Septic Shock in Intensive Care Unit

Objective Despite the recent advances in diagnosis and treatment,sepsis continues to lead to high morbidity and mortality.Early diagnosis and prompt treatment are essential to save lives.However,most biomarkers can only help to diagnose sepsis,but cannot predict the development of septic shock in high-risk patients.The present study determined whether the combined measurement of procalcitonin(PCT),thromboelastography(TEG)and platelet(PLT)count can predict the development of septic shock.Methods A retrospective study was conducted on 175 septic patients who were admitted to the intensive care unit between January 2017 and February 2021.These patients were divided into two groups:73 patients who developed septic shock were assigned to the septic shock group,while the remaining 102 patients were assigned to the sepsis group.Then,the demographic,clinical and laboratory data were recorded,and the predictive values of PCT,TEG and PLT count for the development of septic shock were analyzed.Results Compared to the sepsis group,the septic shock group had statistically lower PLT count and TEG measurements in the R value,K value,αangle,maximum amplitude,and coagulation index,but had longer prothrombin time(DT),longer activated partial thromboplastin time(APTT),and higher PCT levels.Furthermore,the Sequential Organ Failure Assessment(SOFA)score was higher in the septic shock group.The multivariate logistic regression analysis revealed that PCT,TEG and PLT count were associated with the development of septic shock.The area under the curve analysis revealed that the combined measurement of PCT,TEG and PLT count can be used to predict the development of septic shock with higher accuracy,when compared to individual measurements.Conclusion The combined measurement of PCT,TEG and PLT count is a novel approach to predict the development of septic shock in high-risk patients.

冻融劣化作用下煤矸石陶粒混凝土力学性能衰变规律研究

为研究冻融劣化作用下,煤矸石陶粒混凝土力学性能的衰变规律,采用快冻法探究冻融次数和水灰比(0.35、0.45、0.55)对煤矸石陶粒混凝土抗压、抗折和劈裂抗拉强度等力学性能衰变规律的影响。此外,以冻融劣化下抗压强度损伤值为损伤变量,建立不同水灰比的煤矸石陶粒混凝土强度衰变模型。研究表明:煤矸石陶粒混凝土的力学性能与冻融次数成反比,即随着冻融次数增大,其力学性能逐渐降低。随着水灰比的增大,煤矸石陶粒混凝土的力学性能衰减幅度呈现逐渐增大趋势。建立的强度衰变模型符合性较好,精度较高。本研究成果可以为冻融劣化作用下煤矸石陶粒混凝土性能研究提供参考。

基于有限突变模型和大规模数据的19个常染色体STR的实际突变率研究

短串联重复序列(short tandem repeat,STR)已广泛用于法医学亲子鉴定和个体识别中,但STR的突变可能会影响其结果的解释。在大多数类似研究中,由于忽略“隐性”突变现象,STR的突变率被低估。鉴于此,为获得更加准确的STR实际突变率,本研究使用Slooten与Ricciardi提出的有限突变模型和大规模数据,对28,313例(78,739个体)中国北京汉族已确认亲生关系的亲子鉴定案的20个常染色体STR基因座(D3S1358、D1S1656、D13S317、Penta E、D16S539、D18S51、D2S1338、CSF1PO、Penta D、TH01、vWA、D21S11、D6S1043、D7S820、D5S818、TPOX、D8S1179、D12S391、D19S433和FGA;由于有限突变模型中未包含D6S1043的矫正参数,因此本文实际计算其余19个STR基因座的突变率)进行了调查。结果发现,所有基因座均存在突变现象,总计发生1665个突变事件,包括1614个一步突变,34个两步突变,8个三步突变和9个非整步突变。基因座特异性的平均实际突变率在三联体中为0.00007700(TPOX)~0.00459050(FGA),在二联体中为0.00000000(TPOX)~0.00344850(FGA)。此外,本研究还分析了表面和实际突变率、三联体和二联体突变率、父源和母源的突变率之间的关系。研究表明,实际突变率多大于表面突变率,而且μ1^(*)/μ2^(*)(表面突变率)的比值通常也大于μ1/μ2(实际突变率)(μ1^(*),μ1;μ2^(*),μ2分别是一步和两步的突变率),即更多的“隐性”突变被释放出来。而且父源和母源的三联体和二联体的突变率也有存在差异。随后,将这些突变率数据与已发表的中国其他汉族人口的相关研究进行比较,展现出了STR突变率的时间与区域差异。由于样本量大,本研究中还报告了一些少见的突变事件,例如同卵双胞胎突变和“假四步突变”等。综上所述,本研究通过大量数据获得了接近真实的STR突变率的估计值,不仅可为中国法医DNA数据库和群体遗传学数据库提供重要的基础数据,也对开展法医学个体识别、亲权鉴定和遗传学研究具有重要的意义。

Blood perfusion of the contralateral testis evaluated with contrast-enhanced ultrasound in rabbits with unilateral testicular torsion

The changes of blood perfusion of contralateral testis after unilateral testicular torsion remain controversial.In this study,28 New Zealand white male rabbits were randomly divided into five groups.Group A(n=8),the control group,underwent a sham operation on the unilateral testis without inducing testicular torsion.In groups B,C,and D(n=5 each),unilateral testicular torsion was induced,and,after 3,6 or 24 h,respectively,detorsion was performed.In group E(n=5),permanent unilateral testicular torsion was applied.Contrast-enhanced ultrasound was used to observe the blood perfusion of the contralateral testis at the following stages:pre-torsion(preopration),immediately post-torsion(postopration),pre-detorsion,immediately post-detorsion,and late-stage post-detorsion(6-12 h post-detorsion in groups B-D)or at a similar time point(15-21 h post-torsion in group E).Time-intensity curves were generated,and the following parameters were derived and analyzed:arrival time,time to peak intensity,peak intensity,and half-time of the descending peak intensity.The analysis revealed that blood perfusion of the contralateral testis increased immediately after testicular torsion on the opposite side(P<0.05),which increased with prolonged testicular torsion of the other testis.This research demonstrated that contrast-enhanced ultrasound was valuable in evaluating blood perfusion of the contralateral testis after unilateral testicular torsion.

Color Doppler ultrasonographic assessment of the risk of injury to major branch of the midddle hepatic vein during laparoscopic cholecystectomy

OBJEGTIVE: To investigate the causes of hemorrhage from the gallbladder bed during laparoscopic cholecystectomy. METHODS: 617 patients who had received laparoscopic cholecystectomy from September, 2000 to March, 2001 at this hospital were reviewed retrospectively. Ninety-one of these patients were selected randomly for prospective observation. Color Doppler ultrasound was used to examine the cause of venous hemorrhage from the gallbladder bed during laparoscopic cholecystectomy and to examine the anatomic relationship between the gallbladder bed and the branches of the middle hepatic vein in 91 patients preoperatively. RESULTS: A large branch of the middle hepatic vein extended closely behind the gallbladder bed in all 91 patients. The mean distance between the closest point (C point) of this branch to the gallbladder bed was 5.0±4.6 mm. The branch of the middle hepatic vein was completely adherent to the gallbladder bed in 14 (15.38%) of the 91 patients. The distance between this branch and the gallbladder bed was within I mm in 10 (10.99%) of the 91 patients. The inside diameter at C point of this branch was 3.2±1.1 mm. The C point was found on the left side of the longitudinal axis of the gallbladder in 31 (34.66%) of the 91 patients, on the right side in 39 patients (42.86%), just on the axis in 21 patients (23.08%). The venous blood flow rate at the C point was 9.9±3.3 cm/s. CONCLUSIONS: A large branch of the middle hepatic vein passes behind the gallbladder. The inside diameter of this branch is relatively larger. The bleeding of this branch during operation can only be stopped by transfixion. The closest point of this vein to the gallbladder is mostly situated on the right side of the longitudinal axis of the gallbladder. Patients with large branches of the middle hepatic vein close to the gallbladder bed are at risk of hemorrhage during laparoscopic cholecystectomy and should be identified preoperatively with ultrasound.

Extreme high reversible capacity with over 8.0 wt% and excellent hydrogen storage properties of MgH2 combined with LiBH4 and Li3AlH6

Magnesium hydride has attracted great attention because of its high theoretical capacity and outstanding reversibility, nevertheless, its practical applications have been restricted by the disadvantages of the sluggish kinetics and high thermodynamic stability. In this work, an unexpected high reversible hydrogen capacity over 8.0 wt% has been achieved from MgH2 metal hydride composited with small amounts of LiBH4 and Li3AlH6 complex hydrides, which begins to release hydrogen at 276 ℃ and then completely dehydrogenates at 360 ℃. The dehydrogenated MgH2+LiBH4/Li3AlH6 composite can fully reabsorb hydrogen below 300 ℃ with an excellent cycling stability. The composite exhibits a significant reduction of dehydrogenation activation energy from 279.7 kJ/mol(primitive MgH2) to 139.3 kJ/mol(MgH2+LiBH4/Li3AlH6),as well as a remarkable reduction of dehydrogenation enthalpy change from 75.1 k J/mol H2(primitive MgH2) to 62.8 kJ/mol H2(MgH2+LiBH4/Li3AlH6). The additives of LiBH4 and Li3AlH6 not only enhance the cycling hydrogen capacity, but also simultaneously improve the reversible de/rehydrogenation kinetics, as well as the dehydrogenation thermodynamics. This notable improvement on the hydrogen absorption/desorption behaviors of the MgH2+LiBH4/Li3AlH6 composite could be attributed to the dehydrogenated products including Li3Mg7, Mg17Al12 and MgAlB4, which play a key role on reducing the dehydrogenation activation energy and increasing diffusion rate of hydrogen. Meanwhile, the LiBH4 and Li3AlH6 effectively destabilize MgH2 with a remarkable reduction on dehydrogenation enthalpy change in terms of thermodynamics. In particular, the Li3Mg7, Mg17Al12 and MgAlB4 phases can reversibly transform into MgH2, Li3AlH6 and LiBH4 after rehydrogenation, which contribute to maintain a high cycling capacity.This constructing strategy can further promote the development of high reversible capacity Mg-based materials with suitable de/rehydrogenation properties.

Study on a Gas Plunger Lift Model for Shale Gas Wells and Its Effective Application

The problem of efficient gas lift for gas well annulus packers that rely on their own energy plungers is considered.The complex related gas-liquid problem is addressed in the frame of model where the gas inflow dynamics and liquid inflow dynamics of the considered shale gas wells are weakly coupled.On this basis,and with the aiding support of indoor simulation experimental data,a new gas plunger lift design taking into account liquid leakage is obtained.Finally,a dedicated software relying on this approach is developed and used to verify the reliability of the model by means of field examples.

俯冲

没有预演，只要高兴我就收起翅膀从几十米空中直坠而下气流震动我无法描述血冲大脑时的颟顸与豪壮只要高兴。

On Ramanujan Sums over a Dedekind Domain with Finite Norm Property

In this paper,we consider Ramanujan’s sums over arbitrary Dedekind domain with finite norm property.We define the Ramanujan’s sumsη(a,A)andη(B,A),where a is an arbitrary element in a Dedekind domain,B is an ideal and A is a non-zero ideal.In particular,we discuss the Kluyver formula and Hèolder formula forη(a,A)andη(B,A).We also prove the reciprocity formula enjoyed byη(B,A)and the orthogonality relations forη(a,A)in the last two parts.

水稻收割机作业质量在线监测系统研制与试验

针对水稻收割机作业质量(破碎率、含杂率、损失率)在线监测系统缺乏的问题,本文构建了水稻收割机作业质量在线监测系统,其中GPS模块实现田间作业速度和作业位置实时监测,破碎含杂率检测装置实现破碎率、含杂率在线监测,损失率检测装置实现损失率的在线检测,各功能模块通过CAN总线与人机交互系统实现数据通信,开展了相关的田间试验验证系统的性能。研究结果表明,水稻收割机作业质量在线监测系统含杂率的监测精度达到82.76%以上,破碎率的监测精度达到78.69%以上,损失率的检测精度达到73.53%以上;针对作业质量实时变化趋势,人工检测与水稻收割机作业质量在线监测系统检测的结果一致,实验组间人工检测到作业质量参数升高或降低时,系统检测结果也显示该参数数值升高或降低。由此可见,本文构建的水稻收割机作业质量在线监测系统能够实现水稻机械化收获质量可视化监测与报警,能够为智能水稻收割机作业质量参数在线监测及自适应控制策略研究提供有力的技术支持。

Serum LDL Promotes Microglial Activation and Exacerbates Demyelinating Injury in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder(NMOSD)is an autoimmune inflammatory demyelinating disease of the central nervous system(CNS)accompanied by blood-brain barrier(BBB)disruption.Dysfunction in microglial lipid metabolism is believed to be closely associated with the neuropathology of NMOSD.However,there is limited evidence on the functional relevance of circulating lipids in CNS demyelination,cellular metabolism,and microglial function.Here,we found that serum low-density lipoprotein(LDL)was positively correlated with markers of neurological damage in NMOSD patients.In addition,we demonstrated in a mouse model of NMOSD that LDL penetrates the CNS through the leaky BBB,directly activating microglia.This activation leads to excessive phagocytosis of myelin debris,inhibition of lipid metabolism,and increased glycolysis,ultimately exacerbating myelin damage.We also found that therapeutic interventions aimed at reducing circulating LDL effectively reversed the lipid metabolic dysfunction in microglia and mitigated the demyelinating injury in NMOSD.These findings shed light on the molecular and cellular mechanisms underlying the positive correlation between serum LDL and neurological damage,highlighting the potential therapeutic target for lowering circulating lipids to alleviate the acute demyelinating injury in NMOSD.

某幼儿园一起诺如病毒暴发疫情调查

目的分析天津市河东区某幼儿园感染性腹泻暴发的原因及危险因素,为有效控制疫情提供参考依据。方法采用描述流行病学方法描述病例的临床症状及三间分布;采用病例对照研究对相关危险因素进行分析;采集病例、食堂工作人员及食物标本进行病原学检测。结果2020年12月7—15日共报告病例42例(40名幼儿和2名老师),其中临床诊断病例19例,确诊病例(实验室诊断病例)23例,罹患率为45.65%(42/92),临床表现以呕吐(97.62%)、发热(69.05%)及腹痛(61.90%)为主,无重症及死亡病例发生;男女罹患率比较差异无统计学意义(χ^(2)=0.08,P>0.05);各个班级罹患率差异具有统计学意义(Fisher’s精确概率法,P<0.05);疫情传播的危险因素为共用未通风音乐教室(OR=95.67,95%CI:12.02~761.09);共采集30份生物样本进行诺如病毒检测,其中23份标本中检出诺如病毒GⅡ阳性,阳性率为76.67%;共采集6份食物标本进行诺如病毒、致泻性大肠埃希菌、金黄色葡萄球菌及沙门氏菌检测,均未检出。结论本次疫情是一起由诺如病毒GⅡ型感染引起的暴发疫情,共用未通风音乐教室是主要的危险因素。