Effect of periodic wide atmospheric pressure change on CO emission in closed goaf

Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas sampling and abnormal emission in the mine closed goaf,the No.1 coal mine in Dananhu was taken as the research object.Using Fourier transform and Fisher harmonic analysis and other statistical methods,the infuence of the periodic variation of atmospheric pressure on the gas leakage and outfow in the closed goaf was studied.The results showed that there were three atmospheric pressure periods of 15.2 d,1 d and 182.2 d,and the probability was greater than 95%.The time period with the highest number of atmospheric pressure peaks was 7:00–8:00,which accounted for 20.2%of total occurrence number in a day.And the time periods with the highest number of atmospheric pressure trough were 2:00,15:00 and 16:00,accounting for 27.4%.The peak-to-trough transition time was mainly concentrated around 6 h,and the diurnal variation curve of atmospheric pressure was mainly bimodal.The atmospheric pressure change rate was mostly concentrated in 10–50 Pa/h.It was determined that the distance that the gas sampling pipe was pre-laid into the inner side of the closed wall should be greater than 44.4 m,and the CO concentration and atmospheric pressure in the closed goaf were both periodic and negative with atmospheric pressure.The research results have important guiding signifcance for the monitoring,early warning and environmental protection of the goaf.

Target for Power Construction in 9th Five-year Plan Period Set-up

According to the National Meeting on Power Construction and Cost Control held in Beijing on 26th August 1996, the target for power construction in the period of 9th Five- year Plan is set-up as follows:

Thrombelastography and color Doppler flow imaging in the perioperative period after closed lower limb fracture

Objective To observe the changes of thrombelastography (TEG) and color Doppler flow imaging (CDFI) in the perioperative period after closed lower limb fracture.Methods Fasting venous blood samples in the morning from 11 healthy adults were used

论销售在禁渔区或禁渔期非法捕捞渔获物的法律责任

由于现行《中华人民共和国渔业法》第三十八条第二款关于处罚销售在禁渔区或禁渔期非法捕捞的渔获物行为的罚则缺失,导致这种行为没有很好地受到法律规制,严重破坏了渔业资源的可持续发展。文章通过阐述销售禁渔区或禁渔期非法捕捞的渔获物行为的相关概念和危害,分析《渔业法》完善罚则的必要性,并提出法律责任的构成要素和立法建议。

遗煤连续耗氧下供风量对采空区自燃的影响

为提高矿井防治采空区遗煤自燃的能力,文章探究了不同供风量对自燃危险性及最低安全推进速度的影响。以雁南矿I0130101综放工作面为研究对象,由束管监测得到采空区气体体积分数参数,通过封闭耗氧实验测得采空区遗煤不同氧气体积分数下连续的耗氧速度,分析确定其窒息(临界)氧气体积分数。利用FLUENT软件通过编写采空区遗煤耗氧速率的UDF控制程序,对该采空区流场进行不同风量的仿真模拟,得到不同的自燃氧化带宽度。结果表明:工作面风量1200 m^(3)/min时(实际风量),自燃氧化带宽度120 m,最低安全推进速度2.60 m/d,采空区自燃危险程度低;随着工作面供风量的增加,该工作面采空区自燃氧化带的边界向采空区深部移动且宽度增大、最低安全推进速度也逐渐加大,与风量近似呈现出线性关系,自燃危险程度增加。

The Medieval Warm Period and Little Ice Age in the Daihai Area, North China

Rb/Sr ratio, CaCO\-3 content, organic carbon (C\-\{org\}) concentration, magnetic susceptibility and clay mineralogy of 4.0 m sediments samples recovered from Daihai Lake, northern China, are presented in the paper. Weathering and paleoclimatic change history during the last 2300 years is reconstructed in terms of the variations of Rb/Sr ratios in the sediment sequence, including the Little Ice Age and Medieval Warm Period. Our results suggest that the evolution processes of weathering and paleoclimate can be rebuilt in terms of the variations of Rb/Sr ratios in the lake sediment sequence, in combination with magnetic susceptibility, C\-\{org\}, \{CaCO\-3\} contents and clay mineralogy.

Measurement of overburden failure zones in close-multiple coal seams mining

In the Kaiping Coal field,mining of five coal seams,located within 80 m in the Kailuan Group,#5,#7,#8,#9 and#12 coal seam,is difficult due to small interburden thickness,concentrated stress distributions,high coal seam metamorphism,and complex geological conditions.By using the ZTR12 geological penetration radar(GPR)survey combined with borehole observations,the overburden caving due to mining of the five coals seams was measured.The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan,which provides a measurement basis for the control of rock strata in close multiple coal seam mining.For the first time,it was found that the overburden caving pattern shows a periodic triangular caved characteristic.Furthermore,it is proposed that an upright triangular collapsed pile masonry and an inverted triangular with larger fragments piled up alternately appear in the lower gob.The research results show that the roof structure formed in the gob area can support the key overlying strata,which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close coal seams.

Analytical and numerical studies for Seiches in a closed basin with bottom friction

A standing wave oscillation in a closed basin,known as a seiche,could cause destruction when its period matches the period of another wave generated by external forces such as wind,quakes,or abrupt changes in atmospheric pressure.It is due to the resonance phenomena that allow waves to have higher amplitude and greater energy,resulting in damages around the area.One condition that might restrict the resonance from occurring is when the bottom friction is present.Therefore,a modified mathematical model based on the shallow water equations will be used in this paper to investigate resonance phenomena in closed basins and to analyze the effects of bottom friction on the phenomena.The study will be conducted for several closed basin shapes.The model will be solved analytically and numerically in order to determine the natural resonant period of the basin,which is the period that can generate a resonance.The computational scheme proposed to solve the model is developed using the staggered grid finite volume method.The numerical scheme will be validated by comparing its results with the analytical solutions.As a result of the comparison,a rather excellent compatibility between the two results is achieved.Furthermore,the impacts that the friction coefficient has on the resonance phenomena are evaluated.It is observed that in the prevention of resonances,the bottom friction provides the best performance in the rectangular type while functioning the least efficient in the triangular basin.In addition,non-linearity effect as one of other factors that provide wave restriction is also considered and studied to compare its effect with the bottom friction effect on preventing resonance.

Analytical and numerical studies for seiches in a closed basin with various geometric shapes of longitudinal section

Seiches are long-period standing waves with a unique period called a natural resonant period,during which the phenomenon of resonance occurs.The occurrence of resonance in coastal areas can cause destruction to surrounding natural and man-made structures.By determining the resonant period of a given basin,we can pinpoint the conditions that allow waves to achieve resonance.In this study,a mathematical model is developed from the shallow water equations to examine seiches and resonances in various types of closed basin.The developed model is solved analytically using the separation of variables method to determine the seiches’fundamental resonant periods.Comparisons between the analytical solutions and experimental measurements for resonant periods are also provided.It is shown that the analytical resonant period confirms the experimental data for closed basin of various geometric profiles.Using a finite volume method on a staggered grid,the model is solved numerically to simulate the wave profile when resonance phenomenon occurs.Through those numerical simulations,we also obtain the fundamental resonant period for each basin which agrees with the derived analytical period.

An Orbital Period Study of the Contact Binary CK Bootis

Various times of light minima of the contact binary CK Boo are compiled and the correspnoding O C curve is analyzed with Kalimeris at al.’s method (1994). It is shown that the orbital period varies in a quasi sinusoidal form with a period of about 14 years and an amplitude of 0.26 × 10 -5 days while it undergoes a secular period increase dP/dE =+4 97 × 10 -7 days/year. The mechanisms that could explain the changes in the orbital period are also discussed.

围术期闭环管理系统在手术室压力性损伤管理中的效果

目的探讨围术期压力性损伤闭环管理系统在手术室压力性损伤管理中的应用效果。方法成立围术期压力性损伤质管小组,由信息科负责,与医院电子病历系统对接,构建信息化压力性损伤风险评估闭环管理系统,并将2019年1~12月使用该系统前所有手术患者设为对照组,2020年5~12月使用该系统后所有手术患者设为观察组,统计压力性损伤发生率,分析原因及改进措施。结果2019年1~12月本院手术室压力性损伤发生率为0.236‰,2020年5~12月发生率为0.148‰,下降幅度37.7%。结论围术期压力性损伤闭环管理系统具有先进性与科学性,能较好地管理围术期的压力性损伤情况,降低围术期的压力性损伤发生率。

日本江户时期的中国法输入与研究——“锁国”时代的中日法律文化交流

日本江户时期和我国清朝时期,大部分时间都奉行闭关锁国政策。中日两国并无正式邦交,但是中日法律文化交流从未停止。这种交流主要通过日本对中国法律书籍的输入和对中国法的研究而展开。中国法律书籍的输入,又带动了日本对中国法律的研究。锁国时代的中日法律文化交流虽然并未直接促进这一时期日本的“中国式”立法,但对于幕府末年和明治维新初期日本仿照明清律进行立法,仍旧起到了“桥梁”的作用,产生过深远的影响。

极近距离煤层组重复采动顶底板破坏特征微震监测研究

为研究极近距离煤层组重复采动过程中顶底板岩层破坏特征,以平煤十矿己17-33200工作面(下分层)回采作为工程背景,采用微震监测、理论计算等方法,分析其上三带发育特征、周期性运动、底板破坏深度等规律。研究结果表明:下分层重复采动覆岩活动呈现出裂隙带向上叠加发育、中及大能量事件减少、来压周期变长、底板破坏深度减小等特点。裂隙带破断向上增大幅度为40%;通过微震事件总频次和近煤层顶板事件频次“双增长”20%~70%判定,己17煤周期来压步距为25.4 m,周期为5~8 d;与单层回采中大能量事件聚集在近煤层不同,下分层回采呈现空间分布散乱,且中、大能量事件占比下降约28.2%~38.4%,说明极近距离上分层回采对于下分层具有卸压降能的作用;己17回采底板破坏带约20 m,比己15减小,但底板事件向工作面两巷外部延展范围约150 m,较单层回采增大50%,需加强工作面两巷附近及外围底板隐伏裂隙防治水工作。

随机需求下考虑广告遗忘效应的多周期闭环供应链网络均衡

研究由供应商、制造商、再制造商及需求市场组成的多周期闭环供应链网络均衡问题。在随机需求假设下,利用变分不等式方法构建了考虑制造商和再制造商广告投入及广告遗忘效应的多周期闭环供应链网络均衡模型,给出了网络模型的均衡条件,利用算例分析对均衡结果进行了验证和解释,并得到管理学启示。研究表明,无论广告遗忘情境如何,制造商广告投入对回收率及整体利润的影响占据主导;当制造商广告投入水平较再制造商更高时,再制造商利润总是更高,而供应商、制造商及系统整体利润仅在广告遗忘系数小于某阈值时更高;广告遗忘性的存在降低了广告投入对目标市场的正向激励作用,随着广告遗忘系数的增加,回收率、成员企业及系统整体利润均降低,并且在广告遗忘系数呈非固定状态下,其前期的值对系统影响更显著。

基于深度森林的高压断路器弹簧机构状态识别

系统的安全稳定运行与高压断路器的可靠性密切相关,合闸阶段的行程曲线可以反映出高压断路器的弹簧机构机械状态,是实现状态识别的重要判据,因此基于行程数据的弹簧机构状态辨识具有重要的研究意义。文中对合闸弹簧预压缩量减少10 mm或15 mm、分闸弹簧预压缩量减少10 mm或15 mm、油缓冲器抽油10 mL或30 m L、传动构件卡阻档位1或档位2以及正常状态下9种合闸特性曲线进行了采集,然后基于深度森林(deep forest,DF)算法构建辨识模型,最后将识别结果与主成分—支持向量机、随机森林算法进行对比。结果表明,深度森林和随机森林的识别效果一致,且明显优于主成分—支持向量机。此外,深度森林的优势还体现在其避免了随机森林的调参过程,具有更好的识别效率。

全面质量管理在眼科围手术期质量管理评价中的应用

目的运用管理工具,分析判断眼科围手术期质量和安全的关键环节。基于全面质量管理理论,建立眼科围手术期质量管理体系。方法采用文献法和调查咨询法结合,制订调查表;采用德尔菲(Delphi)法对调查对象进行两轮问卷咨询,对围手术期的流程和环节进行评价,选取关键环节开展全面质量管理。结果两轮调查分析建立了4个管理维度20个关键管理环节,调查结果的信度良好,将质量管理需求纳入围手术期管理系统,建立与设计关键因素。结论初步建立眼科围手术期质量管理体系,为医疗质量管理提供方法和思路。

闭环式护理在风湿性心脏病瓣膜置换术患者中的应用效果

目的:分析闭环式护理在风湿性心脏病瓣膜置换术患者中的应用效果。方法:选取2020年3月—2022年4月福建医科大学附属泉州第一医院收治的94例风湿性心脏病瓣膜置换术患者为研究对象。根据随机数表法将其分为对照组与观察组,各47例。两组均采用瓣膜置换术,对照组围手术期给予常规护理,观察组围手术期在对照组基础上采用闭环式护理。比较两组术后3个月心功能分级、生活质量,术后并发症,护理满意度。结果:术后3个月,观察组心功能分级明显优于对照组,观察组Ⅰ级占比高于对照组,Ⅲ级占比低于对照组,差异有统计学意义(P<0.05)。观察组并发症发生率低于对照组,差异有统计学意义(P<0.05)。术后3个月,观察组情感职能、生理职能、躯体疼痛、生理功能、社会功能、生命活力、精神健康及总体健康评分均高于对照组,差异有统计学意义(P<0.05)。观察组护理总满意度明显高于对照组,差异有统计学意义(P<0.05)。结论:闭环式护理能够改善风湿性心脏病瓣膜置换术患者的心功能,同时能够有效降低并发症发生率,可有效提升患者生活质量,并提高护理满意度。

煤层气井低产水期产量预测模型

煤层气产量高低直接关系到区块或气井的开发价值,准确预测煤层气产量是选区、井位部署的关键环节。针对煤层气藏气井生产后期产水较少的情形,根据煤层气渗流连续性方程、煤层气解吸模型,推导得出煤层储层压力分布半解析解。结合压降叠加原理,推导建立了菱形井网中心井的产量预测模型。采用博文盆地Duckworth井组储层基础参数,预测气井产量,并与实际产量进行对比。结果表明,气井生产初期煤储层含水高,受该因素影响,该模型对煤层气生产初期产量预测效果差,预测相对误差达56%;但后期产水量较低时,实际产气量0.19×10^(4) m^(3)/d,预测产气量0.18×10^(4) m^(3)/d,预测相对误差仅5%,预测精度较高;该模型可在产水量较低的煤层气井产量预测中推广应用。

近距离下煤层综放面覆岩结构特征及运动演化规律

针对近距离煤层开采时存在的上、下位基本顶特殊地质条件,运用“三带”理论分析了上煤层采后覆岩结构特征,得出下位基本顶周期来压步距22.09 m,上位基本顶处在弯曲下沉带不发生破坏。建立了下煤层开采时基本顶结构力学模型,计算得出下煤层开采时上位基本顶的周期来压步距31 m,下位基本顶二次破断步距12 m,下位基本顶两次周期来压后会发生上位、下位基本顶同时来压,从而在工作面表现出“强-弱-弱-强”的循环来压现象。矿压监测结果表明,工作面确实出现“强-弱-弱-强”的周期来压现象,在强周期来压时需要提前加强工作面支架稳定性控制以保障工作面安全生产。

具有非线性导数项的二阶常微分方程的正周期解

用正算子扰动方法和锥上的不动点指数理论讨论具有非线性导数项的二阶常微分方程-u″(t)+a(t)u(t)=f(t,u(t),u′(t)),t∈ℝ正2π-周期解的存在性,其中:a:ℝ→(0,+∞)连续,以2π为周期;f:ℝ×[0,+∞)×ℝ→[0,+∞)连续,f(t,x,y)关于t以2π为周期.在非线性项f(t,x,y)满足适当的不等式条件下,得到了该方程正2π-周期解的存在性.