Experimental research into the effect of gas pressure,particle size and nozzle area on initial gas-release energy during gas desorption

Coal and gas outburst is a violent disaster driven by released energy from gas desorption.The initial expansion energy of released gas(IEERG)is a new method to predict coal and gas outburst.In this paper,an instrument for IEERG measurement was developed.Compared with previous setups,the new one which is equipped with three convergent nozzles and quick-release mechanism gets improved in data acquisition and gas sealing and releasing performance.To comprehensively know the effect of gas pressure,particle size,and nozzle area on IEERG,a series of experiments were carried out with this new setup.The variable control test results indicated that the gas pressure-IEERG curves remain the linear trend and the particle size-IEERG curves maintain the negative exponential trend for nozzle areas at 1.13,2.26,and3.39 mm2,respectively.The increase in nozzle area leads to deceases in value of IEERG and absolute value of slope of fitting curves in each test.In addition,the orthogonal experiment showed that the influence of gas pressure,nozzle area,and particle size on IEERG decreases in turn.Only gas pressure had a marked impact on IEERG.This work offers great importance in improving the accuracy of prediction of coal and gas outburst.

Research on the Critical Conditions for Clay Particle Release During Saline Aquifer Freshening Process

Water sensitivity phenomenon occurs during saline aquifer freshening process in seawater intrusion area, and clay particles released in the phenomenon can damage the infiltration capacity of the aquifer. In order to find out the factors and mechanisms for clay particle release, laboratory column infiltration experiments simulating saline aquifer freshening process were designed to measure the critical conditions(critical flow velocity, critical salt concentration and critical ionic strength) and force analysis for clay particle according to DLVO electric double layer theory was employed to illustrate the mechanisms for particle release. The research results showed that critical flow velocity for clay particle release is influenced by salt concentration of injecting solution. When salt concentration of injecting solution is very high, clay particles are not released, indicating that there does not exist a critical flow velocity in this situation. As salt concentration of injecting solution decreases, particles start to be released. The critical salt concentration for clay particle release is 0.052 mol L-1 in our work, which was determined by a constant-flux experiment for stepwise displacement of high concentration Na Cl solution. The critical ionic strength for clay particle release decreases as Ca2+ molar content percentage of the mixed solution of Na Cl and Ca Cl2 increases following the first-order exponential decay equation y = 0.0391e-0.266 x + 0.0015.

Morphological changes of gonadotropin-releasing hormone neurons in the rat preoptic area across puberty

Gonadotropin-releasing hormone （GnRH） neurons in the preoptic area may undergo morphological changes during the pubertal period when their activities are upregulated. To clarify the regulatory mechanism of puberty onset, this study aimed to investigate the morphological changes of GnRH neurons in the preoptic area of GnRH-enhanced green fluorescent protein transgenic rats. Under confocal laser microscopy, pubertal GnRH neurons exhibited an inverted Y distribution pattern. Prepubertal GnRH neurons were generally unipolar and bipolar, and were distinguished as smooth type cells with few small processes or irregular type cells with many spine-like processes in the proximal dendrites. The number of GnRH neurons in the preoptic area and spine-like processes were increased during the course of reproductive maturation. There was no significant difference between male and female rats. Immunofluorescence staining revealed synaptophysin punctae close to the distal end of GnRH neurons, indicating that some presynaptic terminals may form a synaptic linkage with these neurons.

围岩水中玻璃体关键元素动态浸出特性研究

为了获得地下水侵入深部围岩裂隙所致高放玻璃固化体核素释出与迁移参数的变化规律,本研究以高放玻璃固化体中核素在石英石水岩饱和水中的迁移行为为研究对象,开展了动态浸出试验,重点分析研究了元素B、Re和Si在浸出液中的浓度变化以及玻璃的腐蚀情况。结果显示,动态浸出试验150 d后,离子浓度均随反应时间的增加而增大。反应温度为90℃时,地质处置库中流速为40 L/(m^(2)·a)的石英石水岩饱和水中,玻璃柱的腐蚀速率为540 nm/a,3000年后,长1350 mm、直径440 mm、质量400 kg、表面积17 m^(2)的玻璃柱腐蚀深度为1.62 mm,B、Re和Si分别释出元素总含量的12.24%、10.41%和0.18%。

油田集输站库防爆区域的归集与设备选型

集输站库作为油田原油、天然气的中转、贮存、沉降等重要处理场所,具有较高的爆炸危险性,采用防爆电气设备是首选预防措施,根据最新调研情况,80%的站库都存在防爆选型不合理的问题,造成此问题的原因是防爆区域划分不明确,本文论述了集输站库的防爆区域的划分方法和防爆电气的选型原则,并提出几点粗浅建议。

烟区不同类型油菜秸秆腐解及养分释放特性研究

本研究旨在探讨山东和四川烟区适合与烟草轮作的油菜品种,并分析其秸秆腐解及养分释放特性。通过采用尼龙网袋法,在室内模拟田间条件下对2种类型(白菜型和甘蓝型)的4个冬油菜品种进行培养,观察秸秆的腐解过程和养分释放情况。结果显示,培养前10 d,油菜秸秆快速腐解,各养分也快速释放,养分最终释放率表现为K>N>P>C;腐解进程中,秸秆碳氮比有所波动,但大致呈上升趋势;白菜型油菜秸秆的腐解程度、碳和氮的释放率高于甘蓝型油菜,而钾的释放率低于甘蓝型油菜,磷的释放率表现出地区差异;四川烟区油菜秸秆的腐解程度及碳、氮、磷素的释放率高于山东烟区,钾的释放率高于山东白菜型油菜;油菜秸秆腐解可显著提高供试土壤中有机质、氮、磷和钾素的含量,但不同烟区、不同类型油菜秸秆的增效程度有所差异。从秸秆还田利用的角度来看,2烟区中的白菜型油菜品种更适合与烟草轮作种植。

基于Ecopath模型的中街山列岛海域曼氏无针乌贼生态容量的评估

利用Ecopath with Ecosim 6.5(EWE)软件构建了包含17个生态功能组的中街山列岛海域生态模型,在该模型基础上分析研究中街山列岛海域生态系统状况,研究结果表明生态系统中各个功能组的有效营养级在1-4.648之间。中街山列岛海域曼氏无针乌贼的营养级为3.562,属于中等营养级。中街山列岛海域功能组的营养转换效率在0.013-0.991之间。结合相关参数评估计算,中街山列岛海域曼氏无针乌贼的生态容量为30.8 t,可增殖放流曼氏无针乌贼受精卵约224 kg。

关中地区74种立体绿化适宜植物固碳释氧能力研究

在“双碳”目标的推动下,如何在有限的城市建设空间和绿地条件下,遵循绿色低碳途径实现碳中和成为亟待解决的实际问题。聚焦立体绿化这一尺度上的植物固碳释氧能力,选取5类74种关中地区适宜立体绿化的植物,以绿量作为计算指标,估算其固碳释氧量,为科学衡量基于建筑全生命周期评价的立体绿化碳汇提供数据参考。研究发现5类树种固碳释氧能力大小顺序为地被植物>乔木>藤木>常绿灌木>落叶灌木,5类树种里固碳释氧效果最好的分别为桑树、砂地柏、醉鱼草、金银花和常夏石竹。将74种植物的固碳释氧量进行聚类分析,筛选出高固碳释氧型植物共9种。

基于火焰图像识别的材料单体燃烧性能测定

本研究提出了一种基于火焰图像识别技术的材料单体燃烧性能评定新方法。针对现有燃烧测试方法的局限性,如过程参量测定不足和测试规模影响,利用图像识别技术测量单体燃烧试验中火焰的变化规律,建立了建材燃烧发热功率与火焰发光像素面积之间的映射关系。试验中,使用基于树莓派和IMX477R摄像头模块的智能摄像系统,通过OpenCV和Python算法对火焰图像进行处理,实现了火焰像素数量的量化。通过FDS模拟不同燃烧功率的火焰,并与试验数据对比,验证了所提方法的可行性。结果显示,在相同观察角度下,火焰燃烧功率与白色像素数量之间存在接近线性的关系。此外,基于视觉分析的燃烧性能等级判定,以60 kW燃烧能量作为安全阈值,能够快速区分难燃和可燃材料。

沿空留巷动压承载区临时支护研究与应用

为实现沿空留巷动压承载区围岩的有效控制,以屯宝煤矿902工作面运输顺槽为研究背景,通过理论分析、现场实践等方法对沿空留巷动压承载区临时支护进行了研究。在分析沿空留巷开采技术条件的基础上,通过理论分析确定沿空留巷动压承载区1 m范围内所需的支护阻为2 464 kN;设计了ZQ4000/18/39D型强力单元式智能临时支护装置,给出了其主要技术参数与技术特征;结合沿空留巷开采技术条件,提出了具体的临时支护方案。实践表明,临时支护技术应用效果良好,可以满足沿空留巷动压承载区围岩控制的要求。

Influence of temperature and Ca(OH)2 on releasing tar and coal gas during lignite coal pyrolysis and char gasification

The yield of tar and syngas has been investigated by catalytic pyrolysis of Pingzhuang lignite(PZL)over Ca(OH)2 catalyst in temperature range of 600℃-1000℃in a tube furnace.The results show that the yield of volatile pyrolysis increases and char decreases with rising temperature for both raw and catalyzed Pingzhuang lignite.The hydrogen fraction(H2)increased from 20%to 40%for the PZL sample;but,for the PZL-Ca(OH)2 sample,H2 fraction fluctuated randomly between 35%to 42%,with the maximum H2 fraction found at 1000℃.The Gaschromatography mass-spectroscopic(GC-MS)analysis revealed that the maximum tar yield at 800℃and 700℃was obtained for PZL and PZL-Ca(OH)2,respectively.The surface morphology of PZL and PZL-Ca(OH)2 chars underwent different transformation in the presence of catalyst as illustrated by SEM/EDX,FTIR,and BET analysis.Furthermore,char sample was investigated for the carbon conversion and reactivity index using TGA analysis under N2 and CO atmosphere.

衡水湖西湖区土壤重金属污染特征及退田还湖的生态风险初探

衡水湖西湖区作为衡水湖重要的生态系统服务供给区,在开展生态补水和退田还湖的过程中,现有西湖区大部分露滩在淹水后土壤中赋存的重金属释放会产生一定的生态风险。本文从土壤重金属赋存特征、生态风险评价及淹水释放通量风险估算等方面综合评估西湖区土壤生态安全。在调查区域内布设9断面46个样方,以0~60 cm土壤为研究对象,7种管控重金属作为研究要素。采用地累积指数法和潜在生态危害指数法分析西湖区重金属空间分布特征和生态风险等级,并通过室内柱样模拟的方法开展土壤淹水后重金属释放风险评估。西湖区土壤中Zn和Cd的平均含量显著高于河北省土壤背景值,其中重金属Cd累积特征比较明显,中度污染水平以上的区域占97.83%,各重金属含量在空间上呈现南北高中间低的分布规律,西湖区土壤总体处于低风险等级。7种重金属元素的生态风险贡献率依次为:Cd>As>Pb>Cu>Ni>Cr>Zn,其中37.71%的生态风险来自Cd的贡献,其次是As(18.81%)和Pb(4.94%)。淹水后土壤中重金属的释放特征随土地利用类型变化差异显著,其中菜地释放通量最高,果园次之,麦田最低,不同土地利用方式造成的有机质累积可能是土壤重金属释放通量差异的主要原因。此外,衡水湖周边主要以石灰性土壤为主(土壤表层浸出液pH≈9;Ca^(2+)含量为1.135~1.143 mg/g),这些以碳酸盐结合态为主要赋存形式的重金属相对稳定,淹水之后,经跟踪监测发现各重金属水溶态浸出浓度均未超标。因此,西湖区退田还湖后整体的水生态安全风险为低风险。

考虑风电功率预测误差分时补偿的电热联合系统多时间尺度调度

由于风电具有不确定性,风电功率预测误差难以避免。热力系统具备储放热能力,通过调整热功率平移风电功率,可以降低风电功率预测误差的影响。但在风电并入电热联合系统时,风电变化频繁,热力系统具有较大惯性和延迟,难以与风电功率同步;同时,热力系统不同区域对电力系统指令的响应速度也不同。因此,为了解决利用热力系统补偿风电功率预测误差时响应时间不同步的问题,提出了一种考虑风电功率预测误差分时补偿的电热联合系统多时间尺度调度策略。首先,分析概率区间误差评估和实时预测误差评估的评估周期。然后,研究热力系统中供热区域和管网的时间特性。最后,在日前阶段利用响应速度较慢的供热区域补偿评估周期较长的概率区间误差,在实时阶段利用响应速度较快的管网补偿评估周期较短的实时预测误差,建立了多时间尺度调度模型。算例分析表明,所提策略实现了不同调度周期、不同预测误差评估周期、不同热力系统区域响应速度在时间上的匹配,减少了风电功率预测误差的影响,提高了系统的风电消纳能力。

喻清和治疗岭南地区小儿外感发热用药经验的数据挖掘

【目的】采用数据挖掘技术分析喻清和主任医师治疗岭南地区小儿外感发热的用药规律及特点。【方法】收集喻清和治疗小儿外感发热的有效病例的门诊处方,采用SPSS Modeler 18.0统计软件对纳入的处方中药进行频数分析、组方规律分析及药物关联规则分析。【结果】共纳入喻清和治疗小儿外感发热的门诊处方503首,涉及中药110味,其中使用频次>100次的中药有23味,使用频次居前8位的中药分别为甘草、北杏仁、辛夷、板蓝根、布渣叶、荆芥穗、青蒿、蝉蜕。纳入中药的功效分类主要涉及6大类,其中应用最多的3类药物分别为清热药、解表药、化痰止咳平喘药。使用频次较高的药物组合有蝉蜕-青蒿、蝉蜕-板蓝根、青蒿-板蓝根、荆芥穗-辛夷等。【结论】喻清和根据岭南地区小儿发热以外感风邪为主,随四时季节变化而兼挟寒、热、暑、湿、燥等邪气,且入里化热居多的致病特点,用药立足小儿肺和脾胃,以表里并治、清热时顾护阴液为治则,多选用清热及疏风解表药。同时基于岭南地区的地域与气候特点,选用化湿、渗湿之品,善用岭南地区特色中药。

引信的隔热与缓释结构设计及验证

为探索可满足引信在高温高热环境下热缓释要求的泄压和隔热设计方法,以RDX基炸药为装药的某引信为对象,获得了传爆药盒的最小泄压面积与不同厚度隔热材料在不同高温下的背温分布情况.对模拟件进行了快速烤燃和慢速烤燃试验验证,结果表明:泄压孔的设计能显著减弱传爆药盒的反应等级,且泄压面积的增大加强了热缓释效果;对含泄压孔设计的传爆药盒装药包覆装配胶后,一定程度上提升了装药的密封性,使得包覆后反应比无包覆的反应更加剧烈;涂覆隔热层材料可以明显延缓引信点火反应时间,但对反应剧烈程度的影响微弱.

Kisspeptin regulates gonadotropin-releasing hormone secretion in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats

Kisspeptin is essential for activation of the hypothalamo-pituitary-gonadal axis. In this study, we established gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. Rats were injected with 1, 10, or 100 pM kisspeptin-10, a peptide derived from full-length kisspeptin, into the arcuate nucleus and medial preoptic area, and with the kJsspeptJn antagonist peptJde 234 into the lateral cerebral ventricle. The results of immunohistochemical staining revealed that pulsatile luteinizing hormone secretion was suppressed after injection of antagonist peptide 234 into the lateral cerebral ventricle, and a significant increase in luteinizing hormone level was observed after kisspeptin-10 injection into the arcuate nucleus and medial preoptic area. The results of an enzyme-linked immunosorbent assay showed that luteinizing hormone levels during the first hour of kisspeptin-10 infusion into the arcuate nucleus were significantly greater in the 100 pM kisspeptin-10 group than in the 10 pM kisspeptin-10 group. These findings indicate that kisspeptin directly promotes gonadotropin-releasing hormone secretion and luteinizing hormone release in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. The arcuate nucleus is a key component of the kisspeptin-G protein-coupled receptor 54 signaling pathway underlying regulating luteinizing hormone pulse secretion.

控释氮肥对引黄灌区麦后复种青贮玉米养分吸收和品质的影响

针对引黄灌区麦后复种玉米施肥不合理现状,以德美亚1号玉米品种为材料,研究控释氮肥优化施肥对麦后复种青贮玉米养分吸收和品质的影响。结果表明,控释氮肥优化施肥显著提高青贮玉米的鲜草和干草产量,其产量较常规施肥处理分别增加9.58%和7.38%,干草产量增加是通过提高玉米籽粒产量实现的。控释氮肥处理显著提高青贮玉米秸秆和籽粒的氮素养分含量,增加植株氮素养分吸收量。控释氮肥处理玉米秸秆和籽粒中粗蛋白含量分别比常规施肥处理提高10.56%和7.21%,籽粒中粗淀粉含量提高8.17%。控释氮肥优化施肥处理可以提高青贮玉米产量和籽粒品质,增加氮、磷素养分吸收量,减少氮、磷素养分投入,降低环境风险。

不同碳氮比下秸秆腐解与养分释放的动力学特征

【目的】研究不同碳氮比下秸秆腐解和养分释放的动力学特征及其影响因素,为秸秆资源充分利用和煤矿区复垦耕地质量提升提供理论依据。【方法】依托山西煤矿复垦试验基地,开展大田填埋试验。供试玉米和小麦秸秆烘干过2 mm筛,通过添加尿素将玉米和小麦秸秆C/N比分别调节为25和10,以不添加尿素的秸秆(其C/N比分别为52和74)为对照,秸秆均按有机碳8 g称取后混匀,装于尼龙网袋(0.38μm孔径)内,水平埋入试验基地15 cm深的土壤中。在埋入土壤后的第12、23、55、218、281、365天采集尼龙袋内样品,分析玉米和小麦秸秆的干物质残留量、养分(碳、氮、磷和钾)释放的动态变化。【结果】前55 d,添加氮肥加快了玉米秸秆的腐解,以C/N比为25时腐解效果最佳。添加氮肥加快了小麦秸秆的腐解,以C/N比为10时腐解效果最佳。氮的添加可以显著促进前55 d玉米秸秆碳、磷的释放;氮的添加可以显著加快小麦秸秆碳、氮和磷的释放,对小麦秸秆中钾释放的促进作用不显著。小麦和玉米秸秆腐解及氮钾释放的一级动力学方程用积温拟合优于用时间拟合,秸秆磷的释放不适用衰减指数方程拟合。当积温为年积温(4 600℃)时,小麦和玉米秸秆碳、氮、磷和钾释放率的平均值分别为49.2%、39.5%、40.8%和90.3%;当累积积温达到1 125℃时,秸秆钾素释放85%以上。秸秆的腐解主要受温度、有机碳、木质素和半纤维素影响。【结论】施氮能加快玉米秸秆前期的腐解和碳、磷的释放,可以显著加快小麦秸秆的腐解和碳、氮、磷的释放。用温度拟合的方程比时间方程更能反映秸秆的腐解和氮钾释放过程。秸秆腐解主要受土壤温度,秸秆中有机碳、木质素和半纤维素含量的影响。因此,应结合煤矿区的水热条件,进行实时实地秸秆还田并配施适量的尿素,以提高复垦土壤的氮磷钾含量。

控释掺混肥对沿江单季稻产量及磷流失风险的影响

控释掺混肥作为一种高效的新型肥料被广泛用于大田生产。为阐明不同用量控释掺混肥对单季稻产量、磷素利用效率和田面水磷流失风险的影响,以水环境敏感的沿江地区单季稻-休闲的种植模式为对象,研究不施肥(CK)、常规施肥(NPK,总磷量108 kg·hm-2)、控释掺混肥减磷30%(CMF1)、控释掺混肥减磷40%(CMF2)和控释掺混肥减磷50%(CMF3)对沿江单季稻产量、磷素吸收利用和田面水磷形态浓度的影响。结果表明,CMF1、CMF2和CMF3处理均不会对水稻产量造成减产,并能减少单季稻田生态系统磷素盈余量,其中以CMF3处理效果最佳。与NPK处理相比,CMF1、CMF2和CMF3显著减少田面水中总磷、可溶性总磷和颗粒态磷的浓度,田面水总磷降低的比例分别为38.6%、47.9%和50.4%,可溶性总磷降低的比例为42.6%、45.9%和50.8%,颗粒态磷降低的比例为32.4%、58.6%和43.8%,且CMF1和CMF3处理减少了可溶性总磷和磷酸盐的占比,增加了颗粒态磷和可溶性有机磷的占比,改变了田面水磷素分布形态。整体而言,一次性施用控释掺混肥能在保障水稻产量的情况下,节本增收,减少稻田磷盈余量,从而降低田面水磷素浓度,对减少农田磷素流失和农业非点源磷污染防控具有显著效果,其中以CMF2综合经济效益最好,适宜在沿江单季稻区推广应用。