Flashover Probability of Wind Turbine Blade and Impact of Strong Electromagnetic Pulse from Lightning Strikes on Wind Turbine Safety

This paper systematically studies the flashover probability of wind turbine blade lightning arrester and the impact of strong electromagnetic pulses on the local and surrounding wind turbines during lightning strikes.The research results indicate that the flashover probability of direct lightning strikes by the wind turbine blade lightning arrester is almost negligible,and the strong electromagnetic pulse of wind turbine blade during lightning strikes has a serious impact on the electronic equipment of the machine,while the impact on the surrounding wind turbine is relatively small.At the same time,the calculation formula for the reflection of lightning current on the carbon brush between the wind turbine hub and the engine compartment during the flashing of the wind turbine blades is provided,and the calculation method for calculating the spatial gradient distribution of electromagnetic field intensity using Biot-Savart Law theorem is applied.The limitations of using wind turbine blades for lightning protection are pointed out,and a technical route for achieving wind turbine lightning safety is proposed,which can be used as a reference for wind turbine lightning protection technicians.

Optimum Tilt Angle of Flow Guide in Steam Turbine Exhaust Hood Considering the Effect of Last Stage Flow Field

Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional （3D） Reynolds time-aver- aged N-S equations and standard k-e turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30~ to 40~, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effectiveenthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.

Efficacy evaluation of high-frequency ultrasound in the treatment of diabetic peripheral neuropathy with α-lipoic acid combined with traditional Chinese medicine package treatment

Objective:To use high-frequency ultrasound to evaluate the efficacy ofα-lipoic acid combined with traditional Chinese medicine in the treatment of diabetic peripheral neuropathy(DPN),so as to provide a basis for clinical medication and evaluation of therapeutic effect.Methods:From December 2018 to December 2019,110 patients with DPN who met the inclusion and exclusion criteria were divided into observation group and control group according to different treatment plans.The control group was treated withα-lipoic acid,and the observation group was treated withα-lipoic acid combined with traditional Chinese medicine encapsulation treatment,and used high-frequency ultrasound,nerve conduction velocity and serological examination to comprehensively evaluate the effectiveness of the two treatment methods.Results:The mean amplitude of glycemic excursions(MAGE)value of the observation group and the control group after treatment was significantly lower than before treatment(P<0.05);After treatment,the SCV of the ulnar nerve,median nerve,and common peroneal nerve in the two groups was significantly faster than before treatment(P<0.05).Similar to SCV,the MCV of the three nerves measured after treatment in the two groups was significantly faster than before treatment(P<0.05).Compared between the groups after treatment,the three kinds of nerve SCV and MCV in the observation group were significantly faster than those in the control group(P<0.05).The cross-sectional area(CSA)value of the ulnar nerve,median nerve and common peroneal nerve in the observation group after treatment was significantly lower than before treatment(P<0.05).Compared with the control group after treatment,the three nerves CSA in the observation group was significantly lower than that in the control group(P<0.05).Abnormal ultrasound performance:The proportion of abnormal ultrasound performances of the ulnar nerve,median nerve,and common peroneal nerve in the observation group after treatment was significantly lower than before treatment(P<0.05).The composition ratio of internal echo reduction and ambiguity in the observation group after three nerve treatments was significantly lower than that in the control group after treatment(P<0.05).In the correlation analysis,the three kinds of nerve CSA before and after treatment were negatively correlated with SCV and amplitude(P<0.05),and positively correlated with latency(P<0.05).Conclusion:The combination ofα-lipoic acid and Chinese medicine encapsulation technology has a good effect on the treatment and repair of DPN nerve damage,and can be routinely applied in clinical treatment.High-frequency ultrasound can intuitively observe changes in peripheral nerves and can be used to evaluate the prognosis of DPN.

Analysis of the characteristics of diabetic peripheral nerve damage by high frequency ultrasound combined with QTT

Objective: High frequency ultrasound combined with policy thermal perception testing (QTT) was used to analyze the characteristics of nerve damage in diabetic peripheral neuropathy (DPN), and then provided the basis for the clinical prevention, diagnosis and treatment of DPN. Methods: A total of 110 DPN patients admitted to the hospital from December 2015 to May 2018 were selected, and the characteristics of nerve damage in diabetic peripheral neuropathy were analyzed by ultrasound and QTT. Results: In the results of QTT, the abnormal proportion of the CDT, WDT, CPT and HPT of the lower limbs in DPN's were all higher than the upper limbs;The difference of WDT and HPT in the age and course groups of patients in the upper limbs was statistically significant, the abnormal proportion of WDT and HPT in patients aged 60 years or above or with a course of 10 years or more were all above 45%, higher than those in other groups. The patients with larger mean amplitude of glycemic excursions (MAGE) were significantly higher than those with smaller MAGE, regardless of the abnormal proportion of WDT and HPT observed in upper limbs, lower limbs or upper and lower limbs;The results of ultrasonic measurement of nerve cross sectional area showed: the proportion of patients with ulnar nerve and median nerve abnormally thickened in the high age group (≥45 years) and the long course group (>10 years) was significantly higher than that in the low age group (<45 years) and the short course group (<10 years), the proportion of patients with larger MAGE with abnormal enlargement of median nerve was significantly higher than those with smaller MAGE. The thickening of ulnar nerve, median nerve and peroneal nerve was obvious in the patients of MAGE > 4 mmol/L. Conclusion: (1) The main nerve damage in DPN patients was thermal sensation damage, and the lower limb nerve was more vulnerable than the upper limb nerve. (2) The incidence of ulnar and median nerve damage was higher in patients aged 45 years and older or over 10 years of course. (3) Patients with large MAGE (> 4 mmo/L) had higher incidence of median nerve damage. The above characteristics of nerve damage can provide basis for clinical prevention, diagnosis and treatment of DPN.

Metochalcone induces senescence-associated secretory phenotype via JAK2/STAT3 pathway in breast cancer

Breast and lung cancers are the leading causes of mortality and most frequently diagnosed cancers in women and men,respectively,worldwide.Although the antitumor activity of chalcones has been extensively studied,the molecular mechanisms of isoliquiritigenin analog 2',4',4-trihydroxychalcone(metochalcone;TEC)against carcinomas remain less well understood.In this study,we found that TEC inhibited cell proliferation of breast cancer BT549 cells and lung cancer A549 cells in a concentration-dependent manner.TEC induced cell cycle arrest in the S-phase,cell migration inhibition in vitro,and reduced tumor growth in vivo.Moreover,transcriptomic analysis revealed that TEC modulated the activity of the JAK2/STAT3 and P53 pathways.TEC triggered the senescence-associated secretory phenotype(SASP)by repressing the JAK2/STAT3 axis.The mechanism of metochalcone against breast cancer depended on the induction of SASP via deactivation of the JAK2/STAT3 pathway,highlighting the potential of chalcone in senescence-inducing therapy against carcinomas.

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal seam.The controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low cost.In order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be studied.In this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are provided.Based on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating wire.During the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal seam.The stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks being.The repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas extraction.Under the influence of ground stress,the crack propagation in coal seam will be restrained.The difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced cracks.The permeability enhancement effect of CSW is affected by the breakage degree of coal seam.The shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability enhancement.When arranging two adjacent boreholes for CSW permeability enhancement test,the spacing of boreholes should not be too close,which may lead to negative pressure mutual pulling in the early stage of drainage.At present,the accurate method for effectively predicting the CSW permeability enhanced range should be further investigated.

The Relationship between Parental Stress and Child Conformity:The Mediating Role of Resilience

Background:In today’s society,parental stress has become a prevalent and significant issue,impacting not only parents’mental health but also potentially profoundly affecting children’s growth and education.This topic has garnered continuous attention from scholars.The present study aims to delve into the relationship between parental stress and children’s behavior,particularly focusing on children’s conformity and discipline development during crucial stages.This study aims to explore the relationship between parental stress,child conformity,and resilience,and further examines the mediating role of resilience in the relationship between parental stress and child conformity.Methods:We used three scales:the Parental Stress Scale,the Child Conformity Scale,and the Resilience Scale,to survey 890 elementary school students(aged 6–12)and their parents in the Beijing-Tianjin-Hebei region of China.We employed SPSS 26.0 software for data analysis,conducting descriptive statistics,correlation analysis,and mediation effect tests sequentially.In the mediation effect tests,we utilized structural equation modeling(SEM)and regression analysis to examine the mediation effects,ensuring the accuracy and scientific nature of our analysis.Results:Through descriptive statistics,correlation analysis,regression models,and mediation effect tests,we found that parental stress significantly negatively predicts child conformity,while resilience shows a significant positive prediction.Further mediation analysis indicates that resilience plays a partial mediating role between parental stress and child conformity,with the mediation effect accounting for 36.67%.Conclusion:These findings highlight the importance of the family environment on child behavior and provide valuable insights and recommendations for family education practices in the Beijing-Tianjin-Hebei region.Therefore,we suggest future research should further explore the complex relationships among parental stress,child conformity,and resilience,and examine regional differences to better promote children’s overall development.

Heat Recovery from Automotive Exhaust Using Heat Pipes with Limited Fluid Charge

Experiments were conducted in this study to examine the thermal performance of a thermosyphon,made from Inconel alloy 625,could recover waste heat from automobile exhaust using a limited amount of fluid.The thermosyphon has an outer diameter of 27 mm,a thickness of 2.6 mm,and an overall length of 483 mm.The study involved directing exhaust gas onto the evaporator.This length includes a 180-mm evaporator,a 70-mm adiabatic section,a 223-mm condenser,and a 97-mm finned exchanger.The study examined the thermal performance of the thermosyphon under exhaust flow rates ranging from 0–10 g/sec and temperatures varying from 300℃–900℃.The influence of three parameters—inclination angle(5°–45°),water mass(2–5.3 g),and the quantity of non-condensable gas Argon(0–0.6 g)—was investigated to assess their impacts on the thermosyphon’s thermal efficiency.The experimental findings revealed that with 3 g of water and 0.0564 g of argon in the thermosyphon,the condenser reached its highest temperature at around 200℃.The ideal fuel loading rate for the thermosyphon falls between 0.2 and 0.7 g/s.Moreover,as inclination angles rise,outer wall temperatures of the thermosyphon increase.This is attributed to the explicit expansion of the effective heating area within the evaporation section,coupled with an amplified gravitational component of the water flux.Additionally,an upsurge in the quantity of non-condensable gas(NCG)can mitigate temperature gradients on the outer wall,resulting in a decline in the thermosyphon’s performance.The insulation applied to the adiabatic section demonstrated efficacy in augmenting temperature gradients on the outer wall,thereby improving the overall performance of the thermosyphon.As the water charge within the thermosyphon increases,there is a corresponding rise in heat transfer rates both from the exhaust to the thermosyphon and from the thermosyphon to the fuel.

Computational Analysis of Selective Laser Sintering of Inconel 625

A two-dimensional multi-physics finite element model is developed to simulate the Selective Laser Sintering(SLS)process using Inconel 625 powders.The validity of the developed model is first assessed by comparing its results with experimental data.Various factors such as phase transition,recoil pressure,surface tension,and theMarangoni force are considered.The study’s findings underscore that the morphology and thermal-fluid dynamics of the molten pool in the SLS process are predominantly shaped by the influence of the Marangoni force and recoil pressure acting on its surface.The recoil pressure at the front of the laser spot rises exponentially with temperature,making the liquid metal move downward,and creating a depression at the pool’s head.It also causes particles to splash from the pool’s rear edge.The study explores the influence of the backward Marangoni force,where hightemperature liquid flows from the front to the rear of the molten pool,creating a vortex and moving the pool in the rear.Process parameters like laser intensity,scan speed,and spot size were analyzed.The findings indicate that higher laser power lower scanning speed and laser beam spot size lead to increased width and depth of the molten pool.

左乳腺癌保乳术后全乳和锁骨上下及内乳淋巴结区三种放疗方式的剂量学研究

目的:对左乳腺癌保乳术后全乳及锁骨上下、内乳淋巴结引流区三种放疗方式在靶区及危及器官(organs at risk,OARs)的剂量学进行研究。方法:选取2018年1月至2019年10月20例于昆明医科大学第一附属医院行左乳腺癌保乳术后放疗患者的定位CT资料,设计固定野滑窗调强放疗(dynamic multi-leaf collimator,dMLC)、容积弧形调强放疗(volumetric intensity modulated arctherapy,VMAT)和螺旋断层放疗(tomotherapy,HT)三种计划,并对剂量指标进行统计学分析。结果:HT在术后瘤床(plan target volume of tumor bed,PTVtb)的平均剂量(mean dose,Dmean)、D1、适形度(homogeneity index,HI)和全乳及淋巴引流区的计划靶区(plan target volume,PTV)的Dmean、均匀性(conformity index,CI)均优于dMLC和VMAT,并且降低心脏和患侧肺的Dmean、V5、V10、V30。HT在冠状动脉左前降支和右冠状动脉的Dmean以及D1比较中剂量最低,但相比VMAT及dMLC,HT增加健侧乳腺的D1和Dmean。结论:对左乳腺癌保乳术后患者,HT对降低心脏毒性和保护患侧肺最有优势,但对健侧肺低剂量控制不如VMAT和dMLC,dMLC对健侧肺及健侧乳腺低剂量控制最佳,但对心脏及患侧肺的高剂量控制最差。在临床中需根据实际情况选择合适的计划方式。

变压器110 kV穿缆式套管升降装置设计研究

随着主变压器运行年限的增长,密封圈逐渐老化而出现渗漏油缺陷,经常需要吊起套管对密封圈进行更换。目前的作业方式是用吊车将套管吊起进行更换,作业风险高,而且户内封闭式主变室无法使用。为此,设计了一种变压器110 kV穿缆式套管升降装置,通过套环套设在套管上,利用螺栓以及锁紧座对套管进行定位以及锁紧,上方的吊钩组件可调节水平位置和高度,旨在解决更换变压器110 kV穿缆式套管升高座密封圈时存在的问题,既提高了工作效率,也规避了使用吊车误触电的风险,给电力设备和人身安全提供了保障,也为电力电网设备吊运检修提供必要的技术支持。

构建适应数字时代的政府变革理论——评《数字时代的政府变革》

一、引言近年来,数字政府建设备受学界和政府的关注,已经成为我国各级政府提升治理能力和完善治理体系的重要路径。以大数据、物联网、人工智能、云计算等为代表的新一代信息技术快速融入数字政府建设,推动形成了浙江“最多跑一次”、广东“数字政府”改革、江苏“不见面审批”、上海“一网通办”等地方数字化发展经验。正是这些鲜活的地方实践经验引出了在数字时代公共管理学者需要关注和思考的一系列重要议题。

10 min教学法在产科整体护理临床实习教学中的应用效果

目的:分析10 min教学法在产科整体护理临床实习教学中的应用效果。方法:将2022年1—12月期间在广西医科大学第一附属医院产科进行实习的159名学生纳入研究,按照随机数字表法分为常规教学组和10 min教学组。常规教学组79名学生采用传统教学方法,10 min教学组80名学生采用传统教学方法联合10 min教学法。比较两组实习生的考核成绩与教学效果。结果:两组实习生在病例分析与文书书写方面的考核成绩基本一致,差异无统计学意义(P>0.05);常规教学组实习生在理论知识、临床操作、风险评估的考核成绩低于10 min教学组,差异有统计学意义(P<0.05)。常规教学组实习生在医疗面谈、身体检查、人道精神、组织效能、记录呈报、咨商卫教、整体胜任的教学效果评分低于10 min教学组,差异有统计学意义(P<0.05)。结论:将10 min教学法应用于产科整体护理临床实习教学中,不仅可以提高产科护理实习生的考核成绩,还能够改善实习生在护患沟通、了解病情、风险评估等多个方面的临床实践能力,有效提升教学效果。

基于量化评估策略的护理干预在重度子痫前期患者中的应用效果观察

目的 探讨基于量化评估策略的护理干预应用于重度子痫前期患者的效果。方法 选取2019年6月—2021年5月厦门市妇幼保健院接收的80例重度子痫前期患者,采用随机数字表法,分成对照组(n=40)和观察组(n=40),对照组予以常规护理,观察组予以基于量化评估策略的护理,2组均干预至出院。比较2组患者干预前、出院时血压水平、负性情绪[依据汉密尔顿焦虑量表(hamiltom scale,HAMA)和汉密尔顿抑郁量表(hamilton depression scale,HAMD)评估],统计2组不良妊娠结局发生情况。结果 出院时,2组收缩压、舒张压均降低,观察组变化更大(P<0.05);出院时,2组患者HAMA、HAMD评分均降低,观察组变化更大(P<0.05);比较2组不良妊娠结局总发生率,观察组更低(P<0.05)。结论 将基于量化评估策略的护理应用于重度子痫前期患者中,可降低血压水平,缓解负性情绪,改善妊娠结局。

Research Progress of the Antiviral Bioactivities of Natural Flavonoids

Flavonoids are now considered as an indispensable component in a variety of nutraceutical and pharmaceutical applications.Most recent researches have focused on the health aspects of flavonoids for humans.Especially,different flavonoids have been investigated for their potential antiviral activities,and several natural flavonoids exhibited significant antiviral properties both in vitro and in vivo.This review provides a survey of the literature regarding the evidence for antiviral bioactivities of natural flavonoids,highlights the cellular and molecular mechanisms of natural flavonoids on viruses,and presents the details of most reported flavonoids.Meanwhile,future perspectives on therapeutic applications of flavonoids against viral infections were discussed.

结构色材料用于纺织印染领域的研究进展

结构色是通过微纳米结构与可见光的相互作用产生的颜色,也称为物理色。结构色与化学色的产生机理完全不同,颜色性质也有显著区别,其实质是物体自身的特殊周期性结构与光发生衍射、干涉和散射等物理作用所产生的视觉效果。目前,纺织品着色的主要途径是通过在纤维、纺织物上接枝或施加染料及颜料等有色物质,即化学着色。为了克服传统染料光牢度差及带来的环境问题,人们致力于利用颜色性能优异的结构色替代传统的有机染料应用于纺织印染领域。文中综述了结构色的产生原理、结构生色材料的制备与组装方法,以及国内外最新的用于纺织印染结构生色材料的研究进展。最后对该领域未来的研究方向进行了分析,指出存在的关键问题,以促进结构生色材料在纺织领域的拓展应用。

Fingolimod(FTY720) improves postoperative cognitive dysfunction in mice subjected to D-galactose-induced aging

Neurocognitive dysfunction is a common postoperative complication,especially in older adult patients.Fingolimod(FTY720)is a sphingosine-1-phosphate receptor modulator that has been found to be neuroprotective in several animal models of central nervous system disease.However,few reports have examined whether FTY720 could mitigate postoperative cognitive dysfunction.In this study,we investigated whether FTY720 could prevent postoperative neurocognitive impairment in mice subjected to D-galactose-induced aging.We induced an accelerated model of aging by administering an intraperitoneal injection of D-galactose.Subsequently,we performed a partial hepatolobectomy under sevoflurane anesthesia.FTY720(1 mg/kg)was administered intraperitoneally 3 hours before and 24 hours after anesthesia and surgery.Our results indicated that anesthesia and surgery significantly impaired spatial memory in the Y-maze test 6 hours after surgery.We also found that problem solving ability and long-term memory in the puzzle box test on postoperative days 2–4 were significantly improved by FTY720 treatment.Immunohistochemical staining and western blot assay demonstrated that FTY720 significantly inhibited microglial activation in the hippocampal CA1 region of mice 6 hours and 3 days after anesthesia,and down-regulated the expression of synaptic-related proteins postsynaptic density protein 95 and GluR2 in the hippocampus.These results indicate that FTY720 improved postoperative neurocognitive dysfunction in mice subjected to D-galactose-induced aging.This study was approved by the Experimental Animal Ethics Committee of the Third Xiangya Hospital of Central South University of China(approval No.LLSC(LA)2016-025)on September 27,2016.

China published ocean forecasting system for the 21st-Century Maritime Silk Road on December 10, 2018

1 The unique ocean forecasting system (OFS) based on FIO-COM The OFS is based on the surface wave-tide-circulation coupled ocean model developed by the First Institute of Oceanography (FIO-COM), Ministry of Natural Resources, China. The half-century challenge that ocean circulation models must address is that the forecasting/simulated sea surface temperature overheats while the sub-surface temperature is too cold, especially during the summer. Qiao et al.(2004, 2010, 2016) found that the non-breaking surface wave can generate turbulence through wave-turbulence interaction, and they developed the wave-induced mixing theory, which has been confirmed by observations, laboratory experiments and model numerical simulations. As validated by ocean circulation models from various research groups, including Geophysical Fluid Dynamics Laboratory (GFDL) in the US (Fan and Griffies, 2014), Uppsala University of Sweden (Wu et al., 2015), Laboratoire d’Etudes en Geophysique et Oceanographie Spatiale (LEGOS) in France (Malek and Babanin, 2014), Budapest University of Technology and Economics in Hungary (Peter and Kramer, 2016) and the Ocean University of China (Lin et al., 2006), the non-breaking surface waveinduced vertical mixing (Bv) can always dramatically improve the simulation capacity of various ocean circulation models. The First Institute of Oceanography (FIO) research group found that tidal-induced mixing plays a key role in the formation of coastal upwelling, in the bottom mixed layer and in areas with sea mounts (Lv et al., 2006, 2008). With the above breakthroughs, the first surface wavetide-circulation coupled model of FIO-COM was developed in 2013. It was adopted to produce a reanalysis dataset for the period of January 2014 to April 2016, and it has been used for the operational OFS since May 2016. A highly efficient parallel scheme was designed to use the full capacity of Taihu Light with 10 649 600 CPU cores (Qiao et al., 2016), which earned a finalist nomination for the international Association for Computing Machinery (ACM) Gordon Bell Prize.

Elimination mechanism of coal and gas outburst based on geo‑dynamic system with stress–damage–seepage interactions

Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynamic system of coal and gas outburst is proposed.The framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining disturbance.Equations of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor roadway.The results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic system.The scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of outburst.The formation criterion and instability criterion of coal and gas outburst are established.The formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst geo-body.According to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is given.For the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.

Cell replacement for Parkinson's disease:advances and challenges

Parkinson's disease(PD), characterized by the loss of dopaminergic(DA) neurons in the substantia nigra pars compacta(SNpc) of the midbrain, is a prototype neurological disease that is suitable for cellular replacement therapy. Levodopa has been utilized to replace the insufficient dopamine released by degenerating DA neurons since the 1960s and it remains the cornerstone of PD treatment. However, as the disease progresses.