南美奥连特盆地白垩系Napo组Main-M1亚段沉积体系重建及油气勘探意义

厄瓜多尔奥连特盆地是南美安第斯前陆盆地群中最重要的含油气盆地之一,上白垩统Napo组Main-M1亚段是目前勘探开发的主力层位之一,其沉积环境一直存在争议,沉积体系及演化过程尚不明确。本研究基于岩心、测录井等资料,针对Main-M1亚段沉积时期的主要沉积微相类型、沉积体系及演化过程进行了研究。结果表明:研究区位于水动力条件复杂的海陆过渡环境,在东部发育潮汐三角洲,向西部逐渐过渡为浅海陆棚环境;研究区内主要识别出水下分流河道、水下分流河道间、潮汐水道、潮汐沙坝、潮汐沙坪、潮汐水道间等8类沉积微相。根据岩电特征,进一步将Main-M1亚段划分为3个小层。通过分析3个小层的岩性组合演变特征,确定在Main-M1亚段沉积时间内,Auca古隆起逐渐形成,同时挠曲作用导致相对海平面升高,3个小层在垂向上呈水体逐渐变深、潮汐三角洲前缘不断向陆地退缩的形式;基于对Main-M1亚段沉积时期潮汐三角洲—浅海陆棚沉积体系的重建,研究区东部的水下分流河道及前缘沙坝也被认为具有一定的岩性油气藏勘探潜力。

南美奥连特盆地坎潘阶碳酸盐岩建隆的识别及科迪勒拉运动早期抬升对Main-M1储集层沉积的控制作用

厄瓜多尔奥连特盆地Main-M1砂岩储集层是该盆地近年来重要的构造-岩性圈闭勘探目的层系,寻找砂体和岩性尖灭带是Main-M1砂岩勘探的关键。该盆地为晚白垩世弧后热沉降盆地和新生代前陆盆地的叠合盆地,在构造上分为西部逆冲褶皱带、中部前渊带和东部斜坡带,在前渊带发育一系列近N-S走向长轴背斜。综合观察和分析发现,在研究区内长轴背斜上生长了1个碳酸盐岩建隆,地震上具有明显的边界反射形成丘状外观和较连续的弱振幅内部反射,测井上具有厚层、近箱型低GR响应特征。该建隆表明在其沉积的坎潘阶时期,长轴背斜已经开始抬升,将背斜顶部推升至古水面附近,形成建隆局部生长的条件。压实回剥方法恢复古地貌证实,长轴背斜在坎潘阶早期开始发育,构造抬升幅度为7~10 m。由于构造抬升和建隆发育始于Main-M1沉积前,抬升古地貌可影响砂岩沉积。根据背斜上数十口已钻井Main-M1砂体厚度统计,发现背斜顶部砂岩储集层整体较发育,但古建隆顶部砂层厚度减薄或者缺失,在背斜的南部延伸段,构造顶部砂岩缺失,仅在东部侧翼富集。提出了近N-S向背斜古地貌影响Main-M1砂体沉积,使砂岩于富集于构造下倾方向的控砂模式。该模式可形成上倾尖灭型构造-岩性圈闭,从而提供了通过古地貌恢复在奥连特盆地前渊带寻找新圈闭的勘探思路。

Strong shock propagation for the finite-source circular blast in a confined domain

The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible flow.The reflection of the primary shock and its propagation within a confined domain are studied both theoretically and numerically in this research.Under the assumption of strong shock,the scaling law governing propagation of the main shock is proposed.The dimensionless frequency of reflected shock propagation is associated with the confined distance.The numerical simulation for the circular explosion problem in a confined domain is performed for validation.Under the influence of confinement,the principal shock wave systematically undergoes reflection within the domain until it weakens,leading to the non-monotonic attenuation of kinetic energy in the explosion fireball and periodic oscillations of the fireball volume with a certain frequency.The simulation results indicate that the frequency of kinetic energy attenuation and the volume oscillation of the explosive fireball align consistently with the scaling law.

Minimally Invasive Total Arterial Coronary Artery Bypass Grafting in Left Main Stem Disease

Objective: The aim was to show that Minimally Invasive total arterial revascularization for left main stem coronary artery disease, via a left anterior Mini thoracotomy using bilateral internal thoracic arteries is feasible, reproducible and safe. Further, there has been no exclusive data or experience with minimally invasive coronary artery bypass grafting in left main stem disease. Methods: From April 2019 to March 2024, 41 patients with left main stem stenosis, left main equivalent disease and unprotected left main with triple vessel disease underwent off pump minimally invasive multivessel coronary artery bypass grafting using either in situ pedicled Bilateral Internal Thoracic arteries or Left and Right Internal Thoracic artery Y composite conduits at three centers. Bilateral Internal Thoracic arteries were harvested under direct vision. All patients had an Intra-Aortic Balloon Pump inserted via the femoral artery prior to induction of anesthesia, to prevent any hemodynamic instability, arrhythmias, and was removed following completion of the procedure in the operating room without any complications. Efficacy and outcomes were evaluated by i) Primary (MACCE)-Major Adverse Cardiac and Cardiovascular events and ii) Secondary outcome measures including total length of stay, return to full physical activity and quality of life. Mean follow-up was 1.4 years (Maximum was 2.5 years). Results: 41 patients with left main stem coronary artery stenosis, underwent total arterial revascularization using bilateral internal thoracic arteries. Left main stem stenosis was present in 29 patients, Unprotected left main stem stenosis with triple vessel disease in 7 and left main equivalence in 5 patients. In this cohort, 29 patients with only left main stem stenosis had 2 grafts each, 7 patients with left main and triple vessel disease had 3 grafts and 5 patients with left main equivalent disease had 2 grafts respectively. The average number of grafts was 2.2. One patient was converted to open sternotomy as an emergency because of hemodynamic instability and myocardial revascularization was done on cardiopulmonary bypass (2.2%). The average hospital stay was 3.7 days. Ejection fraction was 45% ± 5%. There was one mortality (2.2%) but no major morbidity. The average ICU and hospital stay was 24 ± 4 hours and 3.7 days. All patients were free from major adverse cardiac and cerebrovascular events at follow-up. Conclusions: Multivessel total arterial revascularization using left and right internal thoracic arteries, was performed via a left anterior Mini thoracotomy on patients with left main stem disease and showed that it was safe, reproducible and will help extend the armamentarium of the surgeon in minimally invasive Coronary artery bypass grafting. Concomitantly it helped enhance the potential for shorter hospital stay, increased survival, decreased morbidity, and earlier return to full activity. Furthermore, the safety, efficacy, and outcomes of minimally invasive coronary artery bypass grafting in this high-risk group evaluated by primary and secondary outcome measures have been good in this study.

Analysis of Dry-Wet Climate Change Characteristics and Main Influencing Factors in Main Grain Producing Area of Tibet from 1980 to 2021

Based on the daily meteorological observation data of seven meteorological stations in southern Tibet from 1980 to 2021 (April-October), the temporal and spatial variation characteristics and influencing factors of aridity index ( AI ) in the growing season of major grain producing areas in Tibet were studied by using climate tendency rate, Mann-Kendal test, Morlet wavelet analysis, GIS hybrid interpolation method, Pearson correlation coefficient, contribution rate analysis and other methods. The results showed that the average AI in the main grain producing areas of Tibet was 1.7, which belonged to the semi-arid area, and the overall trend was decreasing (humidifying) (-0.036/10 a). The linear decreasing trend was different in different regions, and the area around Lhatse County was the most significant (-0.26/10 a). AI had no obvious abrupt change, and had long- and medium-term fluctuation characteristics of 24 years, 6 years. The spatial distribution was uneven, and had the characteristics of ‘shrinking arid area and expanding humid area . The contribution rates of the main climate influencing factors of AI varied in different regions. In general, the contribution rates after quantification was as follows: precipitation (34.9%)>relative humidity (28.4%)>sunshine (19.9%)>maximum temperature (12.4%).

Ground response and failure mechanism of gob-side entry by roof cutting with hard main roof

This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.

“Eternal Motion” as a “Form of Movement of a Special Nature” and the Main Condition for the Creation of the Universe

The article hypothesizes that DE and DM (UCM) are a “Form of Motion of a Special Nature”, where “Form of Motion” means “Eternal Motion” as the power of dynamics of different levels and varying degrees of self-sufficiency, and by “Special Nature”, gravitational and two other properties of matter, “tied” to the “Eternal Movement” and completely dependent on it. Carriers of key properties of a “Special Nature” have been established: “0”-DE particles and “3”-DM particles (UDM). The unity of their inherent “motionally-gravitational” properties and the peculiarity of the relationship between “motion” and “gravity” are revealed: the higher the intensity of “Eternal Motion”, the stronger the gravitational properties of matter are manifested (and vice versa). The relationship of “time” with the “vibration frequency” and the “mass” of photons with the “degree of bonding and deformation properties of the field” is shown. The maximum level of gravity has been determined, which allows Nature to successfully create the Universe: such a landmark is the proximity to the property of the Primary Source—the “pure graviton” of the OSP space, the most powerful “motionally-gravitational” particle of the Universe. The reasons for the emergence of such an identity of the gravitational properties of particles with the indicators of a “pure graviton” are established: for “0”-DE particles, this is the acquisition of the function of “freedom of movement”;for “3”-DM particles (UDM), the creation of a special structure—a “double field” (“Main” and “Small”). The presence in the “double field” of specific “tools” for the creation of the worlds of the Universe—gravitational “waves” gives rise to impulses (shocks) of varying intensity and shape. A list of functions performed by “waves” in the “Main” and “Small” fields has been compiled. The specific conditions for the formation of “UDM Streams”, their transformation into a “Vortex” and, under the influence of a powerful Initial Impulse (push), sending them to the “place” of the creation of galaxies, are shown. It is suggested that there is a “Cycle of Matter in Nature” in the closed structure of our Universe due to the “work” of “waves” and the functioning of special “factories” in the form of exotic space objects—Black holes.

A comparative study of the main factors controlling geohazards induced by 10 strong earthquakes in Western China since the Wenchuan earthquake in 2008

Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.

“Treat-Repair-Treat”:Management of Left Main Coronary Compression by a Pulmonary Artery Aneurysm in a Patient with Atrial Septal Defect and Significant Pulmonary Hypertension

Left main coronary compression syndrome(LMCS)may complicate pulmonary artery aneurysms(PAA),usually developed in the context of pulmonary arterial hypertension(PAH).We report the case of a 51-year-old female patient with an atrial septal defect(unsuitable for device closure)complicated by a PAA generating a 90%left main stenosis.The significant PAH held us back from immediate surgery.After specific dual PAH-targeted therapy(sildenafil and bosentan),the atrial septal defect could be closed with a unidirectional valved patch;the PAAinduced LMCS was treated by reductive arterioplasty.The postoperative course was uneventful.Follow-up showed clinical improvement,but PAH treatment was still needed.After three months,coronary angiography showed only an insignificant residual left main stenosis,proving that reductive pulmonary arterioplasty was effective in treating LMCS.Any PAA requires further evaluation for LMCS,a dangerous but treatable complication.The“treat-repair-treat”strategy and shunt-closure with a unidirectional valved patch can both improve surgical prospects of LMCS with shunt-related PAH.

冲击地压主控因素及孕灾机制

随着我国煤矿逐步向深部开采转移,冲击地压灾害日趋严重。在冲击地压从机理认知走向防冲工程进程中,首要的任务是厘清冲击地压孕灾主控因素,并进行风险程度判识。在上百个冲击地压矿井致灾评价分析基础上,提出了导致冲击地压发生的4类客观主控因素:煤岩冲击倾向性、开采深度、坚硬顶板、地质构造,以及3类人为主控因素:煤柱、采空区及采掘卸荷,并对各主控因素对冲击地压孕灾的力学机制进行了分析讨论。在客观主控因素方面,煤岩冲击倾向性是煤岩积聚变形能进而诱发冲击破坏的自身属性;开采深度与巷道围岩内积聚的变形能呈正相关关系,是冲击地压发生的必要条件;坚硬顶板大尺度周期断裂形成的冲击动载及动能是诱发冲击地压的“导火索”;地质构造对冲击地压的影响显著,对于断层构造而言,断层两盘将在开采扰动造成的突发卸荷影响下产生相对“回弹”;煤层变薄区等效弹性模量变大,超前支承压力呈“双峰值”分布,使得冲击影响范围扩大。在人为主控因素方面,煤柱作为高应力集中区,其尺寸、倾角及相对位置等将直接影响冲击地压发生的概率和强度;采空区会诱发超前支承压力集中区内围岩积聚弹性能的突然释放,尤其是在采高较大、顶板垮落不充分的情况下;采掘卸荷会导致应力集中区快速“迁移”,引发煤体内弹性应变能的大量释放,是造成冲击地压的重要外因条件。在此基础上,对山东新汶、山东鲁西、内蒙古鄂尔多斯、陕西彬长、新疆和甘肃等矿区冲击地压孕灾主控因素差异性,进行了对比分析,强调按层次对矿井、采区和工作面进行冲击地压主控因素及其影响程度判识重要性,构建了从降能、释能、阻能到抗能的冲击地压治理工程路径。

四川盆地下寒武统筇竹寺组海相页岩气高产井突破与富集模式

多年来下寒武统筇竹寺组页岩气勘探开发进展缓慢,资201井获高产气流大大增加了该套页岩气规模商业化开发的信心,不同区域及层段富集规律差异及下一步勘探开发方向是筇竹寺组页岩开发面临的首要问题。以四川盆地57口钻井资料为基础,对多口重点井的古生物、沉积、储层等特征进行分析,详细剖析资201井的部署理论依据、筇竹寺组页岩气富集条件及下一步勘探开发方向。从地层研究入手,建立了筇竹寺组地层划分标准,明确筇竹寺组主体发育4套深水陆棚相的富有机质页岩(①至④号层段),其分布受裂陷槽发育控制,裂陷槽内厚度最大。分析了页岩储层发育特征,指出储层压力、孔隙度、含气饱和度从下向上、从裂陷槽外到内呈现增大趋势,储层超压对页岩孔隙保存起到重要作用;基于此结合保存条件等建立了“多层异相、超压保孔”的页岩气超压差异富集模式,指出远离散失通道的超压孔隙发育区(层段)是页岩气富集有利区(层段)。文章指出资201井及周边是未来筇竹寺组页岩气增储上产的主要区域,资源量为8.06×10^(12)m^(3);川西地区具有相当的开发潜力,资源量为0.72×10^(12)m^(3);川南长宁及黔北一带受石墨化及构造活动影响,以寻找远离风化壳及地表露头的超压孔隙发育区为主。

黄芩中国主产区栽培技术差异性调查分析

黄芩是常用的大宗药材,市场需求量大,为了解当前各产区黄芩栽培技术、管理水平、品质和产量的差异,对山西、陕西、甘肃、山东、河北、河南、内蒙古等我国黄芩主产区的生产现状进行调查,发现各主产区的生态环境、栽培方式、施肥技术、病虫害防治、采收加工等方面均存在一定差异。因此,建议当前应进行黄芩生态适宜性区分析及各产区适宜栽培技术研究,以便形成黄芩高产、优质、高效的栽培技术体系,进一步为黄芩栽培提质增效奠定基础。

健全我国粮食主产区利益补偿机制的新思路

粮食安全关乎国运民生,政府在战略上高度重视主产区利益补偿问题。当前,我国粮食产业面临产销区粮食供需矛盾加剧、经济发展差距加大、种粮收益不稳、主产区资源和环境压力激增等诸多压力与挑战,健全粮食主产区利益补偿机制、创新补偿思路是我国保障粮食安全亟待解决的现实难题。因此,在进一步拓展了粮食主产区利益补偿的理论基础上,提出利益补偿的新思路,要以公平、协调和可持续发展实现各区域的共同富裕为导向,形成多维度补偿机制。在纵向上,完善以政府为主导的利益补偿机制,提高补偿资金使用效能,在横向上,制定各区域责任分担机制,积极探索新型产销区协作关系,建立产销区横向利益补偿机制。此外,还要综合考虑主产区发展的显性和隐性损失,通过做好用地文章、提高产业核心竞争力、建立粮食生态补偿机制等途径弥补主产区经济发展的机会成本和粮食生产的资源消耗。

深井松软围岩煤巷采动增跨效应及防控技术

针对深井松软煤巷围岩变形严重、巷道支护困难等问题,以城郊煤矿LW21106工作面沿空巷道为工程背景,建立了采动巷道增跨模型,揭示了采动增跨效应演化机理。通过构建巷道顶板横纵弯曲梁模型,指出顶板横向受力、巷道等效跨度、煤岩强度是巷道围岩损伤破坏的主控因素,提出了采动增跨效应防控对策并进行工业性试验。研究结果表明:受采动影响,巷道经历“初始围岩稳定—围岩裂隙发育扩展—围岩剪切破坏加剧—等效跨度增加”过程;巷道顶板最大正应力与应力集中系数、顶板等效跨度、巷道断面尺寸及埋深成正相关关系;巷道顶板在高应力环境下易发生拉剪破坏,增加顶板锚索数量以及锚索预紧力有利于增强顶板初期完整性。基于巷道变形破坏主控因素,提出“围岩加固–卸压–强化支护”协同防控策略;针对现场条件,采用煤柱侧向切顶+注浆加固并对破碎区域补充锚索强化支护的防控技术。现场监测结果表明,煤柱帮最大移近量为18.89cm,顶板下沉量为25.86cm,两帮移近量为29.65 cm,有效控制了煤巷围岩变形,为深井松软围岩巷道变形控制提供了参考。

急性左主干完全闭塞与次全闭塞的心电图特点和院内死亡因素的分析

目的探讨左主干完全闭塞与次全闭塞的心电图特点差异,并对该类患者院内死亡因素进行分析。方法纳入94例左主干完全闭塞患者(完全闭塞组)和99例左主干次全闭塞患者(次全闭塞组),比较其心电图特点、冠状动脉造影和其他临床资料差异,并对患者的院内死亡因素进行分析。受试者工作特征(ROC)曲线分析心电图特点对左主干完全闭塞患者院内死亡风险的预测价值。分析左主干完全闭塞患者心电图特点与休克和侧支循环的关系。结果与次全闭塞组比较,完全闭塞组Ⅰ、avL、V2—V5导联ST段抬高,avR+avL导联ST段抬高,左前分支传导阻滞、左前分支+右束支传导阻滞比例升高,QRS时限延长,而avR导联ST段抬高和avR+V1导联ST段抬高比例降低(P<0.01)。avR+avL导联ST段抬高预测左主干完全闭塞特异度为0.97,左前分支+右束支阻滞预测左主干完全闭塞特异度为1.00。完全闭塞组院内死亡率为46.8%(44/94),次全闭塞组院内死亡率为14.1%(14/99)。在左主干完全闭塞患者中,Ⅰ、avL、V2—V5导联ST段抬高,QRS时限,休克,无侧支循环,Ⅰ、avL、V2—V5导联ST段抬高合并左前分支+右束支阻滞,Ⅰ、avL、V2—V5导联ST段抬高合并休克对于院内死亡有一定预测价值,曲线下面积(AUC)分别为0.716、0.619、0.766、0.688、0.572、0.785;Ⅰ、avL、V2—V5导联ST段抬高合并休克诊断特异度为0.82,敏感度为0.75。Ⅰ、avL、V2—V5导联ST段抬高合并左前分支+右束支阻滞预测完全闭塞患者院内死亡特异度为0.94。在急性左主干完全闭塞中,Ⅰ、avL、V2—V5导联ST段抬高,左前分支+右束支阻滞和无侧支循环患者中休克比例较高(P<0.05)。完全闭塞患者中,Ⅰ、avL、V2—V5导联ST段抬高患者未建立侧支循环,avR导联(包含avR+V1导联)ST段抬高患者中82.4%存在右冠状动脉侧支循环供应前降支+回旋支范围。而在avR+avL导联ST段抬高患者中69.2%存在右冠状动脉侧支循环供应前降支+回旋支范围。结论左主干完全闭塞与次全闭塞具有不同的心电图特点,左主干完全闭塞的心电图特征可预测院内死亡风险。

美国“去风险”对中国产业链供应链安全的影响及应对

在大国竞争加剧、突发公共卫生事件冲击和乌克兰危机持续等多重不确定性因素叠加的背景下,全球产业链供应链正进入重要的重塑阶段。与此同时,美国先后提出对华“脱钩”“去风险”,以减少其对中国产业链供应链的依赖,这严重影响了全球产业链供应链的稳定畅通。首先,本文界定产业链供应链安全范畴主要包括主体要素安全和结构要素安全。其次,辨析美国“脱钩”“去风险”政策意图的异同,并就现阶段美国“去风险”对中国产业链供应链安全的主要影响和中国所面临的现实挑战进行论述。分析发现,美国“去风险”对中国产业链供应链安全的主要影响包括:一是美国通过控制核心技术、中间品出口和关键资源危及中国产业链供应链主体要素安全。二是通过制造业回流、“近岸外包”“友岸外包”重塑全球产业空间布局,威胁中国产业链供应链结构要素安全。三是通过友好国家网络拉拢盟友,增加中国产业链供应链被排除风险。最后,本文据此提出中国如何在美国“去风险”背景下维护产业链供应链安全稳定的政策建议。

同步辐射装置主信号源的扩展方法研究

主信号源是同步辐射装置的关键组成部分之一,它不仅用于产生同步辐射光源各子系统所需的稳定度极高的参考信号,还用于生成整个装置的控制系统所需的高精度工作时钟。一般使用射频信号源作为主信号源,而商业射频信号源一般只配备单输出通道,远远不能满足同步辐射装置的需要,使用传统功分器对主信号通道进行扩展又存在幅度衰减、精度下降且相位不一致的问题。为解决上述问题,利用射频芯片AD9361,研究了对主信号源的单路输出进行扩展的方法。该方法可根据用户需求完成相应数量的信号通道扩展,设计了AD9361芯片和FPGA主控模块相结合的硬件架构。搭建实验平台,开展了射频信号源在C波段扩展的实验研究,对所提出的扩展方法进行实验验证。实验结果表明,该方法能保证扩展信号的幅度、频率与相位与主信号保持高度一致。

基于子模型的主轴承螺纹疲劳强度分析方法

针对气缸体主轴承螺纹疲劳强度分析与开裂失效问题,基于气缸体主轴承壁疲劳试验构建了虚拟仿真模型,计算获得主轴承壁的应力分布。在此基础上,结合气缸体主轴承壁疲劳试验结果,重新划分网格建立了精细化的主轴承螺纹联接子模型。综合考虑应力梯度、平均应力和表面粗糙度等因素,基于临界平面法和Haigh图建立了主轴承螺纹疲劳强度模型,进行了疲劳强度评估和失效机理分析。结果表明,主轴承螺纹与螺栓联接前几扣的安全系数在螺栓预紧力产生的平均应力影响下逐渐增大,最后一扣位置处安全系数最小为0.8,与试验中开裂位置基本吻合,其开裂原因为模拟气体力主导的应力幅超出材料和结构承载能力。

风电主轴承失效分析与优化设计

风电主轴承是风力发电机组的核心部件,其性能直接影响风机可靠性和寿命。通过对4MW风电调心滚子主轴承进行材料、热处理质量、扫描电镜检测分析,结合Romax轴系仿真模型分析轴承两条滚道的受力状态,结果表明受轴向力、倾覆力矩联合作用,轴承出现偏载是导致一侧滚道疲劳的主要原因。对调心滚子风电主轴承进行优化设计并仿真分析,结果表明通过改变接触角进行非对称设计,可改善轴承受力状态。风电主轴承的失效分析与优化设计研究,可为大功率风电主轴承设计提供参考。

滇中地区主要森林凋落物有效截留量及其影响因素

[目的]研究滇中地区主要森林类型凋落物有效截留量差异及其影响因素,为该地未来植被恢复和森林管理提供科学支撑。[方法]利用样方调查法、烘干法和浸泡法分析了昆明市双河—磨南德水源林自然保护区内的地带性次生常绿阔叶林(SF)、针阔混交林(TF)、旱冬瓜林(ACF)、华山松林(PA)、成熟云南松林(OPY)、幼龄云南松林(YPY)、银荆林(AD)7种主要森林类型凋落物未分解层(OL)和半分解层(OF)的有效截留量及其影响因素。[结果](1) 7种森林类型凋落物厚度为2.06~7.57 cm,其中OL层1.10~4.30 cm, OF层0.83~3.93 cm,凋落物层厚度排序为TF>ACF>PA>OPY>SF>AD>YPY,凋落物蓄积量为4.75~17.45 t/hm^(2),其中OL层占比为32.02%~62.48%,OF层占比为37.52%~67.98%,凋落物层蓄积量排序为TF>PA>SF>OPY>ACF>AD>YPY。(2)凋落物最大持水率为115.3%~170.7%,初始吸水速率为3.65~5.62 g/(g·h),凋落物持水率和浸水时间的关系可用对数函数y=aln(x)+b表示,吸水速率与浸水时间可用幂函数y=kt~n表示。(3)凋落物最大持水量为7.05~32.19 t/hm^(2),排序为PA>TF>SF>OPY>ACF>AD>YPY,有效截留量为5.45~25.34 t/hm^(2),以TF最高(25.34t/hm^(2)),PA(24.99 t/hm^(2))和SF(24.62 t/hm^(2))次之,YPY最低(5.45t/hm^(2)),影响有效截留量的场地特征主要为蓄积量、自然含水率、分解强度以及厚度,影响有效截留量的水动力过程主要是最大失水量、前6.0 h平均吸水速率和前2.0 h平均吸水速率。[结论]滇中地区未来植树造林应以针阔混交林为主,注重对地带性次生常绿阔叶林的保育,采取辅助自然更新的措施促进人工纯林向混交林演化,同时减少踩踏、收集凋落物等人类活动的干扰,从而增加森林生态系统凋落物的水源涵养能力。