An effective Dynamic Moire method was presented to determine the critical time of crack instable propagation in rock dynamic fracture. Two pieces of grating were installed near the notch of Short Rod specimen to form ...An effective Dynamic Moire method was presented to determine the critical time of crack instable propagation in rock dynamic fracture. Two pieces of grating were installed near the notch of Short Rod specimen to form the Moire fringes, then the COD versus time could be monitored from the movement of the Moire fringes, and finally the critical time could be determined from the velocity of COD. This method was also compared with another one.It could be concluded that the critical time determined by Dynamic Moire method corresponds with that of the Transmitted Wave method at the loading rates from 103 to 104 MPa·m(1/2)·S(-1).展开更多
Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influenc...Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influence the loss rate and dilution rate, etc, will determine whether the experimental research is successful or not. By employing energy method of limit analysis and finite element numerical simulation method, the critical backfill height was determined under the prerequisite condition of its stability, which put forward theoretical basis for reasonable and correct selection of backfill’s parameters. The result showed that the first backfill could not keep stable for NPCM, while the other was able to.展开更多
科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜...科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜索(Improved Bald Eagle Search,IBES)算法优化双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)的组合水质等级预测模型。首先,采用CRITIC法确定各水质指标的权重,加权求和获得一项综合水质指标,从而提出一种改进的水质评价指标体系,以为BiLSTM提供更丰富、更可靠的水质特征信息。其次,在训练过程中引入Logistic映射和莱维飞行策略,并设计交叉共享及准反向搜索策略优化秃鹰搜索(Bald Eagle Search,BES)算法,以提升其种群多样性,增强寻优能力。最后,通过IBES算法迭代寻找BiLSTM的最佳学习率、隐藏层节点数以及正则化系数的超参数组合,进一步提高其预测水平。结果显示:与IBES-BiLSTM、BES-BiLSTM、GA-BiLSTM、PSO-BiLSTM和BiLSTM等模型相比,CRITIC-IBES-BiLSTM模型进行水质等级预测的准确率、精准率、召回率及F_(1)均最高,且具有更好的稳定性。展开更多
In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear r...In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.展开更多
This paper is devoted to the application of branch mode method in the critical speed ana-lysis of compound rotating systems, in which the distributed inertia including gyroscopic effectand distributed elastic support ...This paper is devoted to the application of branch mode method in the critical speed ana-lysis of compound rotating systems, in which the distributed inertia including gyroscopic effectand distributed elastic support are taken into account. Finally, the method introduced in this paper is used to calculate the critical speeds of anew-type spindle on the spinning frame. The first three critical Speeds are calculated and com-pared with the values obtained from the experimental approach and other theoretical methods.The results show that they are in good agreement with each other.展开更多
Though novel reading is a common experience to everybody,little has been researched to help average readers to understand a novel.In practice,there are two ways for them to understand a novel:one is to use literary cr...Though novel reading is a common experience to everybody,little has been researched to help average readers to understand a novel.In practice,there are two ways for them to understand a novel:one is to use literary criticism theories and the other is to refer to professional critics'criticism directly.However,the trouble is that the two methods are either time-consuming or far from convincing.In this paper,an experimental reading method is discussed to help average readers enhance reading experience.It aims at reaching the goal of reading without criticism,which,through making clear the aim of reading,putting main focus on the story only,will help readers to have a better understanding of reading.展开更多
锂离子电池储能电站火灾事故频繁发生且损失严重,对锂离子电池储能电站火灾风险开展研究可有效预防火灾的发生。首先根据物理-事理-人理(WSR)理论,构建锂电池特性、消防设施、安全管理和人员因素4个一级指标、12个二级指标和32个三级指...锂离子电池储能电站火灾事故频繁发生且损失严重,对锂离子电池储能电站火灾风险开展研究可有效预防火灾的发生。首先根据物理-事理-人理(WSR)理论,构建锂电池特性、消防设施、安全管理和人员因素4个一级指标、12个二级指标和32个三级指标的锂离子电池储能电站火灾风险评价指标体系;然后运用序关系分析(G1)法确定各评价指标的主观权重,采用CRITIC法(Criteria Importance Though Intercriteria Correlation,CRITIC)确定客观权重,基于拉格朗日乘法优化后的最小信息熵原理确定组合权重,并结合云模型理论建立锂离子电池储能电站火灾风险评价模型。以某磷酸铁锂储能电站为例开展火灾风险等级评价,结果表明:储能电站火灾风险综合云特征值为(71.3104,1.2142,0.2568),火灾风险等级处于“中风险”,在运行环境和防火设计等方面存在较严重的问题并亟需改进。评价结果与实际火灾风险等级相符,实例证明锂离子电池储能电站火灾风险评价模型能够较准确地反映储能电站火灾风险情况,为锂离子电池储能电站火灾预防与风险管控提供参考。展开更多
文摘An effective Dynamic Moire method was presented to determine the critical time of crack instable propagation in rock dynamic fracture. Two pieces of grating were installed near the notch of Short Rod specimen to form the Moire fringes, then the COD versus time could be monitored from the movement of the Moire fringes, and finally the critical time could be determined from the velocity of COD. This method was also compared with another one.It could be concluded that the critical time determined by Dynamic Moire method corresponds with that of the Transmitted Wave method at the loading rates from 103 to 104 MPa·m(1/2)·S(-1).
文摘Non-pillar continuous mining(NPCM) is regarded as a high-efficient, high-level and one-step mining technology, which can be divided into two substopes. Back fill stability status in substope I, which directly influence the loss rate and dilution rate, etc, will determine whether the experimental research is successful or not. By employing energy method of limit analysis and finite element numerical simulation method, the critical backfill height was determined under the prerequisite condition of its stability, which put forward theoretical basis for reasonable and correct selection of backfill’s parameters. The result showed that the first backfill could not keep stable for NPCM, while the other was able to.
文摘科学有效地预测水质对于水环境的可持续发展和人类健康具有重要意义,为此以固原市某黄河断面的水质监测数据为研究对象,提出了基于指标客观性的权重赋权(Criteria Importance Though Intercriteria Correlation,CRITIC)法和改进的秃鹰搜索(Improved Bald Eagle Search,IBES)算法优化双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)的组合水质等级预测模型。首先,采用CRITIC法确定各水质指标的权重,加权求和获得一项综合水质指标,从而提出一种改进的水质评价指标体系,以为BiLSTM提供更丰富、更可靠的水质特征信息。其次,在训练过程中引入Logistic映射和莱维飞行策略,并设计交叉共享及准反向搜索策略优化秃鹰搜索(Bald Eagle Search,BES)算法,以提升其种群多样性,增强寻优能力。最后,通过IBES算法迭代寻找BiLSTM的最佳学习率、隐藏层节点数以及正则化系数的超参数组合,进一步提高其预测水平。结果显示:与IBES-BiLSTM、BES-BiLSTM、GA-BiLSTM、PSO-BiLSTM和BiLSTM等模型相比,CRITIC-IBES-BiLSTM模型进行水质等级预测的准确率、精准率、召回率及F_(1)均最高,且具有更好的稳定性。
文摘In reactor physics tests, it is important to monitor sub-criticality continuously during criticality approach. Reactivity measurements by the inverse kinetics method are widely used during the operation of a nuclear reactor. This technique is successfully applied at sufficiently high power level or to a core without an external neutron source where the neutron source term in point reactor kinetics equations may be neglected. For operation at low power levels or in the sub-critical domain, the increase in the fluctuation of the neutron signal may cause difficulties in the evaluation of reactivity and the effect of direct emission from the external neutron source may not be neglected. Therefore, contribution of the neutron source must be taken into account and this implies knowledge of a quantity proportional to the source strength, which calls the source term and then it should be determined. The research work has been conducted to measure reactivity with source term using a dedicated reactivity measurement system by the Least Square Inverse Kinetics Method (LSIKM). Application to a simulator of HANARO research reactor, Korea Atomic Energy Research Institute (KAERI), with known source strength and reactivity worth has showed consistent and satisfactory agreement.
文摘This paper is devoted to the application of branch mode method in the critical speed ana-lysis of compound rotating systems, in which the distributed inertia including gyroscopic effectand distributed elastic support are taken into account. Finally, the method introduced in this paper is used to calculate the critical speeds of anew-type spindle on the spinning frame. The first three critical Speeds are calculated and com-pared with the values obtained from the experimental approach and other theoretical methods.The results show that they are in good agreement with each other.
文摘Though novel reading is a common experience to everybody,little has been researched to help average readers to understand a novel.In practice,there are two ways for them to understand a novel:one is to use literary criticism theories and the other is to refer to professional critics'criticism directly.However,the trouble is that the two methods are either time-consuming or far from convincing.In this paper,an experimental reading method is discussed to help average readers enhance reading experience.It aims at reaching the goal of reading without criticism,which,through making clear the aim of reading,putting main focus on the story only,will help readers to have a better understanding of reading.
文摘锂离子电池储能电站火灾事故频繁发生且损失严重,对锂离子电池储能电站火灾风险开展研究可有效预防火灾的发生。首先根据物理-事理-人理(WSR)理论,构建锂电池特性、消防设施、安全管理和人员因素4个一级指标、12个二级指标和32个三级指标的锂离子电池储能电站火灾风险评价指标体系;然后运用序关系分析(G1)法确定各评价指标的主观权重,采用CRITIC法(Criteria Importance Though Intercriteria Correlation,CRITIC)确定客观权重,基于拉格朗日乘法优化后的最小信息熵原理确定组合权重,并结合云模型理论建立锂离子电池储能电站火灾风险评价模型。以某磷酸铁锂储能电站为例开展火灾风险等级评价,结果表明:储能电站火灾风险综合云特征值为(71.3104,1.2142,0.2568),火灾风险等级处于“中风险”,在运行环境和防火设计等方面存在较严重的问题并亟需改进。评价结果与实际火灾风险等级相符,实例证明锂离子电池储能电站火灾风险评价模型能够较准确地反映储能电站火灾风险情况,为锂离子电池储能电站火灾预防与风险管控提供参考。
