Understanding the combustion behavior of electric bicycle batteries and unveiling its relationship with fire extinguishing

In this study,a detailed analysis of the combustion behaviors of the lithium iron phosphate(LFP)and lithium manganese oxide(LMO)batteries used in electric bicycles was conducted.This research included quantitative measurements of the combustion duration,flame height,combustion temperature,heat release rate,and total heat release.The results indicated that LMO batteries exhibited higher combustion temperatures of 600–700°C,flame heights of 70–75 cm,a significantly higher heat release rate of40.1 k W(12 Ah),and a total heat release of 1.04 MJ(12 Ah)compared to LFP batteries with the same capacity.Based on these experimental results,a normalized total heat release(NORTHR)parameter was proposed,demonstrating good universality for batteries with different capacities.Utilizing this parameter,quantitative calculations and optimization of the extinguishing agent dosage were conducted for fires involving these two types of batteries,and the method was validated by extinguishing fires for these two types of battery packs with water-based extinguishing fluids.

A Novel Pre-control Method of Vehicle Dynamics Stability Based on Critical Stable Velocity during Transient Steering Maneuvering

The current research of direct yaw moment control（DYC） system focus on the design of target yaw moment and the distribution of wheel brake force. The differential braking intervention can effectively improve the lateral stability of the vehicle, however, the effect of DYC can be improved a step further by applying the control of vehicle longitudinal velocity. In this paper, the relationship between the vehicle longitudinal velocity and lateral stability is studied, and the simulation results show that a decrease of 5 km/h of longitudinal velocity at a particular situation can bring 100° increasing of stable steering upper limit. A critical stable velocity considering the effect of steering and yaw rate measurement is defined to evaluate the risk of losing steer-ability or stability. A novel velocity pre-control method is proposed by using a hierarchical pre-control logic and is integrated with the traditional DYC system. The control algorithm is verified through a hardware in-the-loop simulation system. Double lane change（DLC） test results on both high friction coefficient（μ） and low μ roads show that by using the pre-control method, the steering effort in DLC test can be reduced by 38% and 51% and the peak value of brake pressure control can be reduced by 20% and 12% respectively on high μ and low μ roads, the lateral stability is also improved. This research proposes a novel DYC system with lighter control effort and better control effect.

Lack of transcriptional coordination between mitochondrial and nuclear oxidative phosphorylation genes in the presence of two divergent mitochondrial genomes

In most eukaryotes,oxidative phosphorylation(OXPHOS)is the main energy production process and it involves both mitochondrial and nuclear genomes.The close interaction between the two genomes is critical for the coordinated function of the OXPHOS process.Some bivalves show doubly uniparental inheritance(DUI)of mitochondria,where two highly divergent mitochondrial genomes,one inherited through eggs(F-type)and the other through sperm(M-type),coexist in the same individual.However,it remains a puzzle how nuclear OXPHOS genes coordinate with two divergent mitochondrial genomes in DUI species.In this study,we compared transcription,polymorphism,and synonymous codon usage in the mitochondrial and nuclear OXPHOS genes of the DUI species Ruditapes philippinarum using sex-and tissue-specific transcriptomes.Mitochondrial and nuclear OXPHOS genes showed different transcription profiles.Strong co-transcription signal was observed within mitochondrial(separate for F-and M-type)and within nuclear OXPHOS genes but the signal was weak or absent between mitochondrial and nuclear OXPHOS genes,suggesting that the coordination between mitochondrial and nuclear OXPHOS subunits is not achieved transcriptionally.McDonald-Kreitman and frequency-spectrum based tests indicated that M-type OXPHOS genes deviated significantly from neutrality,and that F-type and M-type OXPHOS genes undergo different selection patterns.Codon usage analysis revealed that mutation bias and translational selection were the major factors affecting the codon usage bias in different OXPHOS genes,nevertheless,translational selection in mitochondrial OXPHOS genes appears to be less efficient than nuclear OXPHOS genes.Therefore,we speculate that the coordination between OXPHOS genes may involve post-transcriptional/translational regulation.

外翻式与传统式颈动脉内膜切除术治疗颈动脉狭窄有效性和安全性的Meta分析

目的:通过Meta分析的手段评价外翻式与传统式颈动脉内膜切除术(CEA)治疗颈动脉狭窄有效性和安全性。方法:利用计算机检索PubMed、Embase、中国知网、万方等中英文数据库系统,获取了外翻式与传统式颈动脉内膜切除术治疗颈动脉狭窄的临床对照试验资料,并利用RevMan 5.4统计学程序,进行了Meta分析。结果:本研究共纳入11篇文章,外翻式颈动脉内膜切除术(eCEA)组(试验组)术中转流管应用数量占比低于传统式颈动脉内膜切除术(cCEA)组(对照组)[RR=0.17,95%CI(0.06,0.51),P=0.001];试验组的手术时间短于对照组[MD=-40.47,95%CI(-58.85,-22.09),P<0.0001];试验组的术后再狭窄率低于对照组[RR=0.43,95%CI(0.22,0.83),P=0.01]。结论:eCEA相对于cCEA在治疗颈动脉狭窄过程中可以减少术中转流管应用,缩短平均手术时间,降低术后再狭窄发生率。但是二者具体的治疗效果和安全性仍然需要大量高质量研究数据来长时间的验证。

骨髓间充质干细胞外泌体miR-126-3p靶向CCR1抑制非小细胞肺癌细胞恶性增殖及转移

目的探讨骨髓间充质干细胞(bone marrow stromal cells,BMSCs)来源的外泌体中miR-126-3p靶向趋化因子受体1(chemokine receptor 1,CCR1)对肺癌细胞增殖、迁移和侵袭的影响。方法培养BMSCs,提取外泌体并通过外泌体标志蛋白CD63和TSG101进行鉴定;外泌体共培养A549细胞不同时长(0、24、48、72 h)后,CCK-8检测细胞存活率,q RT-PCR检测miR-126-3p和CCR1 m RNA表达,Transwell实验检测细胞迁移和侵袭能力;Western blotting检测CCR1、上皮钙黏蛋白(E-cadherin,E-cad)、神经钙黏蛋白(N-cadherin,N-cad)和波形蛋白(Vimentin)相对表达。结果外泌体呈边缘高亮、中间灰暗的圆形或椭圆形杯状结构,粒径分布范围152 nm左右,有CD63、TSG101蛋白表达;外泌体中miR-126-3p表达高于A549细胞,A549细胞中CCR1 m RNA表达高于外泌体,而在A549细胞与外泌体共培养后,A549细胞中miR-126-3p表达升高,CCR1表达降低;A549细胞与外泌体共培养0、24、48、72 h,细胞的存活率、迁移和侵袭能力和CCR1、N-cad和Vimentin蛋白表达及CCR1 m RNA表达均随着培养时间的延长逐渐降低,而miR-126-3p水平和E-cad蛋白表达随着培养时间的延长逐渐升高。结论BMSCs来源的外泌体与A549细胞共培养可提高细胞中miR-126-3p的表达,miR-126-3p通过靶向抑制CCR1表达可降低A549细胞增殖、迁移和侵袭能力。

赶黄草叶茶总黄酮、游离氨基酸及槲皮素浸出动力学分析

目的:探究赶黄草叶茶冲泡过程中总黄酮、游离氨基酸及槲皮素浸出量随冲泡时间和冲泡温度的变化规律。方法:通过紫外分光光度法、高效液相色谱法(HPLC)测定总黄酮、游离氨基酸和槲皮素浸出量,使用二阶动力学模型和阿伦尼乌斯公式进行动力学拟合、动力学参数计算。结果:在60~100℃范围内冲泡60 min,总黄酮浸出量和槲皮素浸出量随冲泡温度和冲泡时间的增加而增加;60~90℃范围内冲泡60 min,游离氨基酸有相同的浸出规律,温度上升至100℃冲泡20 min后,游离氨基酸热损失较多。二阶动力学模型能较好拟合三者的浸出情况,相关系数高,冲泡温度与二阶速率常数k线性关系良好,总黄酮、游离氨基酸、槲皮素浸出活化能分别为16 628.201,23 415.139,14 975.396 J/mol。结论:赶黄草叶茶中的总黄酮、游离氨基酸和槲皮素浸出量随冲泡时间和冲泡温度变化显著,三者浸出在60~90℃范围内符合二阶动力学模型,可使用该模型对其浸出量进行预测。

Mn13钢基材表面真空钎焊Al_(1.2)CoCrFeNi_(2.1)高熵合金的微观组织与性能

针对传统钢材Mn13钢等在大规模应用中暴露出的低应力耐磨性差、低温脆性和易生锈等问题,采用在Mn13钢表面焊接具有高强度、良好的延展性和耐蚀性的Al_(1.2)CoCrFeNi_(2.1)近共晶高熵合金来改善其表面性能。采用BNi2钎料通过真空钎焊的方式在Mn13钢表面钎焊Al_(1.2)CoCrFeNi_(2.1)高熵合金,并对高熵合金母材和钎焊接头的微观组织与力学性能进行了探究,同时研究了真空钎焊温度对钎焊层微观组织和力学性能的影响。实验结果表明:母材Al_(1.2)CoCrFeNi_(2.1)高熵合金的显微组织由FCC相和有序B2相组成,钎焊后合金组织中B2相体积分数增加,显微维氏硬度从(436±15.7)HV升至(472±7.1)HV;钎焊接头的微观组织主要为Ni基的固溶体相和硼化物相,焊缝中心主要以CrB为主,扩散区则以B元素与母材元素形成的硼化物为主;钎焊温度过低或者过高会在焊缝形成气孔及硼化物,从而降低钎焊接头的剪切强度,当钎焊温度为1 050℃时,焊接接头的剪切强度达到最大值684.6 MPa。

Molecular phylogenetics and population demographic history of Amphioctopus fangsiao,inferred from mitochondrial and microsatellite DNA markers

Amphioctopus fangsiao(Cephalopoda:Octopodidae)is an important commercial species in the coastal waters of China.In recent years,however,the resource of A.fangsiao have declined because of habitat destruction and overfishing.To analyze the genetic variations of A.fangsiao caused by the fluctuation of resources,the population genetic structure of nine sampling locations collected from the Bohai Sea to the South China Sea were investigated,using mtDNA COI fragments and microsatellite DNA.The results of F-statistics,AMOVA,STRUCTURE and PCA analyses showed three phylogeographic clades(Clades A,B and C),revealing limited genetic exchange between north and south populations.These clades diverged in 2.23(Clades A and B)and 3.67(Clades A,B and C)million years ago,during the dramatic environmental fluctuations,such as sea level and temperature changes,have exerted great influence on the survival distribution pattern of global organisms.Our results for low genetic connectivity among A.fangsiao populations provide insights into the development of management strategies,that is,to manage this species as separate management unit.

A circRNA–miRNA–mRNA network analysis underlying pathogenesis of human heart failure

BACKGROUND The molecular mechanisms of heart failure(HF) are still poorly understood. Circular RNA(circRNA) has been discovered in the heart in increasing numbers of studies. The goal of this research is to learn more about the potential roles of circRNAs in HF.METHODS & RESULTS We used RNA sequencing data to identify the characteristics of circRNAs expressed in the heart and discovered that the majority of circRNAs screened were less than 2000 nt. Additionally, chromosomes One and Y had the most and least number of circRNAs, respectively. After excluding duplicate host genes and intergenic circRNAs, a total of 238 differentially expressed circRNAs(DECs) and 203 host genes were discovered. However, only four of the 203 host genes of DECs were examined in HF differentially expressed genes. Another study used Gene Oncology analysis of DECs host genes to elucidate the underlying pathogenesis of HF, and it found that binding and catalytic activity accounted for a large portion of DECs. Immune system, metabolism, and signal transduction pathways were significantly enriched. Furthermore, 1052 potentially regulated miRNAs from the top 40 DECs were collected to build a circRNA-mi RNA network, and it was discovered that 470 miRNAs can be regulated by multiple circRNAs, while others are regulated by a single circRNA. In addition, a comparison of the top 10m RNAs in HF and their targeted miRNAs revealed that DDX3Y and UTY were regulated by the most and least circRNA, respectively.CONCLUSION These findings demonstrated circRNAs have species and tissue specific expression patterns;while circRNA expression is independent on host genes, the same types of genes in DECs and DEGs worked in HF. Our findings would contribute to a better understanding of the critical roles of circRNAs and lay the groundwork for future studies of HF molecular functions.

Changing trends in gastric and colorectal cancer among surgical patients over 85 years old:A multicenter retrospective study,2001–2021

BACKGROUND Whether patients over 85 years old with gastrointestinal cancer should undergo surgery remains controversial.We aimed to describe the changing trends of characteristics to provide more information to decision makers,and strive to find appropriate surgical plan.AIM To describe the changing trends of characteristics to provide more information to decision makers,and strive to find appropriate surgical plan.METHODS A total of 218 gastric cancer(GC)patients and 563 colorectal cancer(CRC)patients who underwent surgery between 2001 and 2021 were enrolled in this retrospective analysis.Changes in clinicopathological features,surgical treatments,and survival status were analyzed longitudinally at 5-year intervals.RESULTS Only 14 GC patients underwent laparoscopic surgery where 219 CRC patients had this procedure.Cardia and esophagogastric junction cancer increased in GC patients,and the proportion of sigmoid colon cancer decreased in CRC patients.Pulmonary infection gradually became the most common postoperative complication,its incidence in period 4 reached 48.79%.However,the incidence of anastomotic leakage decreased from 26.79%to 9.38%(P<0.01).Additionally,30-d mortality significantly decreased from 32.14%to 9.01%.Increases were observed in 5-year overall survival(OS)in GC patients from period 1 to period 4(18.18%vs 33.32%,respectively)and CRC patients(0 vs 36.32%,respectively).Disease-free survival(DFS)also increased in GC and CRC patients(7.14%vs 27.74%and 0 to 36.03%,respectively).The average survival time of GC patients following radial lymphadenectomy was higher than in patients that underwent limited lymphadenectomy(26 vs 22 mo,respectively),the same was seen in CRC patients(44 vs 33 mo,respectively).This advantage was particularly evident in patients with TNM I,but not in patients with TNM II/III period cancer.CONCLUSION The safety as well as effectiveness of surgery in ultra-elderly patients is increasing.Radical lymphadenectomy has advantages in patients with TNM I gastrointestinal cancer,but not TNM II/III.

深水探井转开发井一体化技术

深水探井和开发井钻井作业费用高昂,降低深水勘探的经济成本已经成为深水油气资源开发的核心课题之一。基于中国南海区域深水探井转开发井一体化技术作业实践,分别提出了一体化开发经济性评价方法和一体化开发技术可行性评价方法,形成了深水探井转开发井的油气田勘探开发一体化技术,为推进深水油气田开发进程提供技术助力。结果表明,海上深水探井转开发一体化技术能够通过将获得发现的探井转化为开发井,节省缩短建产时间,实现有效降低作业成本,在深水海域油气勘探开发中具有广阔的应用前景。

Tracked robot with underactuated tension-driven RRP transformable mechanism:ideas and design

Robots with transformable tracked mechanisms are widely used in complex terrains because of their high adaptability,and many studies on novel locomotion mechanisms have been conducted to make them able to climb higher obstacles.Developing underactuated transformable mechanisms for tracked robots could decrease the number of actuators used while maintaining the flexibility and obstacle-crossing capability of these robots,and increasing their cost performance.Therefore,the underactuated tracked robots have appreciable research potential.In this paper,a novel tracked robot with a newly proposed underactuated revolute‒revolute‒prismatic(RRP)transformable mechanism,which is inspired by the sit-up actions of humans,was developed.The newly proposed tracked robot has only two actuators installed on the track pulleys for moving and does not need extra actuators for transformations.Instead,it could concentrate the track belt’s tension toward one side,and the unbalanced tension would drive the linkage mechanisms to change its configuration.Through this method,the proposed underactuated design could change its external shape to create support points with the terrain and move its center of mass actively at the same time while climbing obstacles or crossing other kinds of terrains,thus greatly improving the climbing capability of the robot.The geometry and kinematic relationships of the robot and the crossing strategies for three kinds of typical obstacles are discussed.On the basis of such crossing motions,the parameters of links in the robot are designed to make sure the robot has sufficient stability while climbing obstacles.Terrain-crossing dynamic simulations were run and analyzed to prove the feasibility of the robot.A prototype was built and tested.Experiments show that the proposed robot could climb platforms with heights up to 33.3%of the robot’s length or cross gaps with widths up to 43.5%of the robot’s length.

低分子量鲶鱼蛋白肽的酶解工艺优化及氨基酸分析

以鲶鱼酶解液多肽含量为指标,采用响应面分析法优化鲶鱼的酶解条件,继而对在此条件下得到的酶解液进行氨基酸组成分析和多肽分子量的分布测定。结果表明:最佳酶解工艺条件为料液比1∶2.7(g/mL)、pH 6、酶解温度57℃、酶解时间300 min。氨基酸分析结果也符合FAO/WHO所提出的蛋白评价标准。最后通过GPC凝胶质谱分析后可确定样品中多肽的相对分子质量主要集中在700.0~2800.0 g/mol之间。该成果可为后续鲶鱼相关的新型调味发酵制品的开发提供一定的理论依据。

ATWS事故应对要求及在研究堆中的应用研究

ATWS事故作为核电厂运行经验反馈所暴露的事故,核工业界对它的认识经历了一个长期的过程。对于商用压水堆核电厂,ATWS事故应对已形成一套完整的方法,而对于高功率研究堆,由于结构及特性与普通压水堆的差异,其ATWS事故要求也有所差异。本文回顾了ATWS事故的演变历程,分析了压水堆相关的标准规范,针对高功率研究堆,提出了ATWS事故分析的一般要求,对相关堆型安全分析工作的开展提供了条件。

复发性流产蜕膜组织中细胞凋亡与侵袭、血管新生的相关性研究

目的:研究复发性流产(RSA)蜕膜组织中细胞凋亡与侵袭、血管新生的相关性。方法:选择在自贡市妇幼保健院就诊的复发性流产患者作为研究的RSA组,同期在自贡市妇幼保健院自然分娩且无流产病史的孕妇作为研究的对照组。采集蜕膜组织并检测凋亡基因、侵袭基因的mRNA表达量及促血管新生分子的蛋白含量,采集血清并测定抗血管新生分子的蛋白含量。结果:RSA组蜕膜组织中Bcl-2的mRNA表达量显著低于对照组,Bax、Caspase-3、Caspase-9、TRAIL的mRNA表达量显著高于对照组;RSA组蜕膜组织中MMP2、MMP9的mRNA表达量以及VEGF、Ang-1、Ang-2、Tie-2的蛋白含量显著低于对照组且与Bcl-2的mRNA表达量呈正相关,与Bax、Caspase-3、Caspase-9、TRAIL的mRNA表达量呈负相关;蜕膜组织中TIMP1、TIMP2的mRNA表达量及血清中sFlt-1的蛋白含量显著高于对照组且与Bcl-2的mRNA表达量呈负相关,与Bax、Caspase-3、Caspase-9、TRAIL的mRNA表达量呈正相关。结论:RSA蜕膜组织中促凋亡基因表达增多、抗凋亡基因表达增多且细胞过度凋亡与侵袭不足、血管新生减少有关。

高铁用进口EA4T钢车轴的组织和力学性能

研究了高铁用进口EA4T钢车轴的显微组织和力学性能,分析了组织和力学性能的均匀性。结果表明:车轴中存在CaS、Al2O3及少量硅酸盐等非金属夹杂物,沿表面至心部夹杂物的数量增多;车轴不同位置的显微组织均为回火马氏体、贝氏体和少量先共析铁素体,自表面向心部先共析铁素体的尺寸增大、数量增多,组织不均匀;车轴的拉伸性能和硬度均满足标准要求,但心部因先共析铁素体含量较多,抗拉强度明显较低;车轴纵向存在带状组织,因此其横向冲击韧性较差;车轴试样的拉伸断口存在较多小而深的韧窝,说明其塑性良好,断裂方式为韧性断裂,而冲击断口存在明显的河流花样和韧窝,断裂方式为脆韧混合断裂。

镀层碳纤维增强铜基复合材料的制备及其性能研究

采用化学镀工艺分别在碳纤维表面施加Cu层、Ni层或Cu+Ni镀层,对不同镀层碳纤维进行900℃热处理,使用真空热压烧结方法制备不同镀层碳纤维增强铜基复合材料。通过光学显微镜、扫描电子显微镜、能谱分析仪和X射线衍射仪对复合材料组织形貌、界面元素分布和物相进行分析,并对复合材料的物理及力学性能进行测试。结果表明,经过900℃高温处理,镀Cu层对碳纤维结构无影响,镀Ni层会造成碳纤维结构向石墨结构发生转变,在碳纤维表面Cu+Ni镀层可以有效地降低碳纤维发生结构转变。Cu+Ni镀层碳纤维增强的铜基复合材料较Cu镀层碳纤维及Ni镀层碳纤维增强的铜基复合材料具有更高的显微硬度和压缩强度,但导电性略低于镀Cu碳纤维增强的铜基复合材料。

患者体验评价研究与进展

本文评述了患者体验相关内容和国内外患者体验的研究现状与进展,对患者体验及患者满意度进行了比较。文章建议加强对患者体验理论和测评方法及患者体验分析方法等方面的研究,制定符合中国国情的患者体验调查与评价规范,从而建立更为科学有效、符合我国国情的患者体验评价体系。

船用核动力工况划分的一些思考

基于始发事件频率的工况划分是船用核动力安全设计的基础。船用核动力始发事件按频率的工况划分,目前主要参考压水堆核电厂,由于两者之间存在一些差异,此类工况划分不完全适用于船用核动力,主要表现在不同工况间的频率截断值和设计基准事故选取的频率截断值2个方面,对此本文调研了国内外标准要求、航海等领域的考虑。在此基础上,初步提出了基于船用核动力特点的工况划分和设计基准事故的频率截断值,为相关设计工作提供一定的参考。

不同栽培措施对中稻“黄华占”生长和产量的影响

为研究不同栽培措施对江汉平原中稻的影响,采用L_(9)(3^(4))正交试验设计,对中稻“黄华占”连续两年采用播种期、施氮量、基本苗、水层进行不同栽培因素组合试验,探索不同栽培措施对中稻“黄华占”生长和产量的影响。结果表明,播种期和施氮量能显著影响生育期,播种期每推迟1期生育期缩短1.7~2d,施氮量每增加50kg/hm^(2)生育期延长0.3~2d;施氮量与基本苗对产量关系密切,施氮量为150kg/hm^(2)和移栽的基本苗60×10^(4)株/hm^(2)时产量最高,平均达到8898.30kg/hm^(2);施氮量与基本苗主要通过影响单位面积有效穗进而影响产量,单位面积有效穗与产量呈显著正相关(R^(2)=0.6859,P<0.05)。综合考虑,“黄华占”最佳的栽培因素组合为播种期4月25日,施氮量纯N 150kg/hm^(2),基本苗60×10^(4)株/hm^(2),移栽后7d内统一灌水5cm。