Application of aspirin and low molecular weight heparin in major orthopedic surgery:Meta analysis of a randomized controlled trial

Objective:The perioperative period of major orthopedic surgery is associated with a high risk of thrombosis,but the best chemopreventive agent for thrombosis prophylaxis is still inconclusive.For this reason,this paper evaluated the efficacy and safety of aspirin versus low-molecular heparin using a Meta-analysis.Methods:Ten randomized controlled studies on the application of aspirin and low-molecular heparin for the prevention of deep vein thrombosis in orthopedic major surgery were retrieved by computer searches of PubMed,CochraneLibrary,WebofScience,China Knowledge Network,Wanfang,and Vipul databases according to inclusion and exclusion criteria,and the literature was managed using Endnote software,and the data were analyzed using Revman 5.3 software was used to perform Meta-analysis of the extracted data,focusing on the effects of these two drugs on pulmonary embolism,deep vein thrombosis,major bleeding events,minor bleeding events,wound complications,mortality and blood loss within 90 days after major orthopedic surgery.Results:(1)Ten randomized controlled trials of high quality were included,with a total of 12,974 patients,7,026 in the aspirin group and 5,948 in the low-molecular heparin group;(2)Meta-analysis showed that aspirin had a higher incidence of pulmonary embolism(OR=1.59,95%CI:1.02 to 2.49,P=0.04)and deep vein thrombosis(OR=1.60,95%CI:1.26 to 2.02,P=0.0001)than low molecular heparin;(3)The incidence of major bleeding events(OR=0.85,95%CI:0.47 to 1.55,P=0.60),minor bleeding events(OR=0.79,95%CI:0.55 to 1.12,P=0.18),adverse wound reactions(OR=0.79,95%CI:0.48 to 1.31,P=0.36),mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)in both drug groups,mortality within 90 days(OR=0.69,95%CI:0.20 to 2.31,P=0.55)and perioperative blood loss(MD=0.69,95%CI:0.20 to 2.31,P=0.55)were not statistically significant.Conclusion:Low-molecular heparin was superior to aspirin in the prevention of pulmonary embolism and lower extremity deep vein thrombosis after major orthopedic surgery,but the safety and adverse drug reactions of both groups were basically similar.Based on this,the authors recommend that low-molecular heparin should be preferred for the prevention of deep vein thrombosis in major orthopaedic surgery;however,the inclusion of randomized controlled trials remains limited,necessitating high-quality,large-sample,long-term follow-up clinical studies.

柴金解郁安神片调控CaMKII和Cofilin双信号通路改善抑郁症海马谷氨酸能神经元突触重塑

目的探讨柴金解郁安神片调控钙/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKII)和Cofilin双信号通路,改善抑郁症海马谷氨酸能神经元突触重塑的分子机制。方法皮质酮联合脂多糖建立抑郁症体外细胞模型,实验设正常组、模型组、GR阻断剂组、GR激动剂组、CX3CR1阻断剂组、CX3CR1激动剂组、柴金解郁安神片组、柴金解郁安神片联合GR激动剂组、柴金解郁安神片联合CX3CR1激动剂组,观察星形胶质细胞、小胶质细胞、前扣带皮层(anterior cingulate cortex,ACC)和海马神经元形态结构变化;检测ACC和海马谷氨酸能神经元激活及突触重塑情况;免疫荧光、Western blot分别检测海马谷氨酸能神经元内突触重塑相关谷氨酸受体2A(GRIN2A)、GRIN2B、CaMKII、MK2、Cofilin蛋白表达水平。结果柴金解郁安神片能明显改善胶质细胞、ACC和海马神经元损伤,并抑制ACC和海马谷氨酸能神经元异常激活,同时下调GRIN2A、GRIN2B、MK2蛋白,上调CaMKII、Cofilin蛋白,继而改善海马谷氨酸能神经元突触可塑性损伤和突触重塑。结论柴金解郁安神片能有效改善抑郁症海马谷氨酸能神经元突触重塑,其分子机制与调节突触重塑相关NR/CaMKII、MK2/Cofilin信号通路有关。

可降解Zn-Li合金吻合钉的自然时效与降解机制研究

作为力学性能良好,降解速率适中的可降解金属,Zn基合金的应用前景十分广阔。研究了自然时效对Zn-Li合金性能的影响以及Zn-Li合金吻合钉的体外降解机制。通过拉伸试验和电化学试验分析时效时间对Zn-Li合金丝力学性能和耐蚀性的影响。采用浸泡实验,根据吻合钉质量变化分析不同模拟液对Zn-Li吻合钉降解速率的影响,采用扫描电子显微镜分析Zn-Li吻合钉不同部位的降解模式。结果表明,时效2.0 a的Zn-Li合金丝比时效1.0 a的拉伸强度低43.86 MPa,伸长率下降24.17%,腐蚀电势由-1.07 V下降至-1.12 V,腐蚀电流密度增加13%。Zn-Li吻合钉在模拟体液中降解速率最大,钉脚的微电偶腐蚀为最严重的腐蚀形式。

靛玉红通过下调Cyclin A2阻滞细胞周期抑制小鼠Lewis肺癌的体内外及网络药理学研究

目的研究中药成分靛玉红在体内外对小鼠Lewis肺癌(LLC)的抑制效果及对细胞周期的调节作用。方法通过细胞毒性实验探究靛玉红在体外对小鼠LLC细胞的抑制作用。构建肺癌原位小鼠模型,随机分为模型组(磷酸盐缓冲液灌胃,每天1次)和靛玉红低、中、高剂量组(25 mg/kg、50 mg/kg、100 mg/kg灌胃,每天1次)、顺铂组(2 mg/kg腹腔注射,每3天1次),连续3周,记录生存期和体质量。通过活体成像法记录小鼠肺癌进展,取肺肿瘤组织,称重并计算抑瘤率。通过网络药理学预测靛玉红治疗肺癌的核心靶点和通路。Western blot法分别验证靛玉红在体外对LLC细胞及在体内对小鼠肺癌组织中细胞周期蛋白A2(Cyclin A2)表达的影响;免疫组织化学染色(IHC)法和实时荧光定量逆转录聚合酶链式反应(RT-qPCR)法分别检测靛玉红对小鼠肺癌组织中Cyclin A2蛋白及其编码基因CCNA2表达的影响。流式细胞术和IHC法分别检测靛玉红对小鼠肺癌肿瘤细胞的细胞周期和肺癌肿瘤增殖抗原Ki-67表达的影响。结果靛玉红在体外对小鼠LLC细胞的抑制作用呈剂量和时间依赖性,24 h、48 h、72 h的半抑制浓度(IC_(50))分别为188.7μmol/L、109.0μmol/L、58.3μmol/L。与模型组比较,靛玉红中剂量组小鼠肺部荧光表达降低(P<0.05),生存率提高(中位生存期延长7 d),肿瘤抑制率较高(37.76%),且对小鼠体质量没有明显影响(P>0.05)。网络药理学分析表明,靛玉红抑制肺癌可能通过调控细胞周期及Cyclin A2实现。进一步研究证明,靛玉红通过抑制Cyclin A2,导致细胞周期S期阻滞,抑制肿瘤细胞增殖。结论靛玉红体外抑制小鼠LLC细胞,体内通过下调肺癌肿瘤细胞Cyclin A2导致细胞周期阻滞,抑制肿瘤进展,延长肺癌小鼠生存期。

酚酸基纳米金修饰电极检测食品中的亚硝酸盐和亚硫酸盐

基于酚酸良好的还原性和无污染性建立酚酸基纳米金传感体系,以实现亚硝酸盐和亚硫酸盐的灵敏检测。采用不同酚酸还原氯金酸制备纳米金(Gold nanoparticles,AuNPs),通过紫外光谱和交流阻抗法获得还原效果最佳的酚酸为没食子酸(Gallic acid,GA)。利用电沉积法制备GA@AuNPs@Au电极,并由线性扫描伏安法(Linear scanning voltammetry,LSV)表征亚硝酸盐和亚硫酸盐的电化学行为。优化体系条件为:GA浓度1 mmol/L、孵育温度70℃、反应时间60 min、pH6.0磷酸盐缓冲溶液浓度0.15 mol/L。亚硝酸盐和亚硫酸盐浓度在0.001~7 mmol/L范围内与氧化峰电流分别呈良好的线性关系(R2>0.994),检出限分别为0.20μmol/L和0.24μmol/L(S/N=3)。该修饰电极的重现性和稳定性良好,可用于实际样品中亚硝酸盐和亚硫酸盐的同时测定。

线粒体移植治疗肌少症的潜力

背景:肌少症是衰老引起的骨骼肌质量和力量下降的一种综合性疾病,是老年人面临的主要健康挑战。越来越多的证据表明,线粒体功能障碍在肌少症的发病机制中起着关键作用。目的:总结线粒体质量控制失调导致肌少症的机制,探讨线粒体移植可能是治疗肌少症的潜在靶点。方法:以“sarcopenia,mitochondrial dysfunction,mitochondrial quality control,mitochondrial transplantation,limitations”和“肌少症,线粒体功能障碍,线粒体质量控制,线粒体移植,局限性”为关键词,检索PubMed和CNKI数据库2009-2023年间相关文献。结果与结论:线粒体功能障碍在肌少症发病机制中发挥关键作用,线粒体移植可能通过改善线粒体生物能量学和调节线粒体相关信号通路成为治疗肌少症的可能策略。虽然部分临床前和临床研究证实线粒体移植治疗各种疾病的潜力,但关于线粒体转移的具体细节方面仍有一些亟待解决的问题。

基于机载LiDAR点云的电力线提取和三维重建方法

从LiDAR点云数据中提取电力线进行三维重建已经成为安全巡检的重要技术手段。本文提出一种电力线提取与重建方法,对获取的LiDAR点云数据,通过高程阈值分割法和直线检测得到直线方程提取电力线,并通过电塔定位实现电力线分档;然后,通过直线模型和悬链线模型结合的方法对提取的分档电力线进行三维建模。实验结果表明,该算法能实现电力线的提取和分档,且重建模型能实现电力线的三维重建,对电力巡线具有实际的应用意义。

EarthingMethod for Protection of a Railway Rail Weighbridge System against Lightning

The rail weighbridge system of a railway freight station is introduced firstly, and then the earthing method for protection of the rail weighbridge system against lightning based on YLG-60 equipotential bonding surge protection device is shown.

基于准稳态过程的混流泵启动性能优化

在ANSYS Workbench的基础上结合OptiSLang优化设计软件,对混流泵启动过程进行优化.利用准稳态理论和全流域模型计算数据,建立了混流泵准稳态启动过程的水力性能响应面替代模型.通过NSGA遗传算法优化内部流动状态,降低启动过程中的涡致能量损失,从而提升混流泵的水力性能.将原始混流泵与优化后混流泵的外特性、叶片压力分布进行对比,并分析混流泵内部涡结构,验证了所提出的准稳态启动过程水力性能优化方案的可行性.研究结果表明:叶片进口安放角α1,α4,α5,叶片出口安放角β1,β2,β3,β4,β5,叶片包角φ和叶片厚度系数θ对混流泵加权平均扬程和加权平均效率的影响程度较大;对比不同启动时刻下混流泵的叶片压力分布,发现该方法能够有效提升混流泵启动中后期的瞬态扬程和启动中期的水力效率.

Robust Timing Constraints for Granitic Magmatism and Hydrothermal Mineralization in the Tieshanlong W-Sn Ore Field,Eastern Nanling Range,South China

The Tieshanlong ore field is an important part of the Nanling Range,which is famous worldwide for its W-Sn mineralization.Notably,the mineralization age of the Tieshanlong ore field is not well constrained,and our field investigation reveals that granitic emplacement occurred at different stages.However,previous studies have not distinguished these multiple stages of magmatism.The Tieshanlong granite complex is closely related to the Huangsha quartz vein-type W-Sn deposit and Tongling skarn-type Cu-W-Sn deposit in this field.Through field investigations and isotopic age analyses,this work studies the relationship between multistage magmatic activity and mineralization in the Tieshanlong ore field.LA-ICP-MS zircon U-Pb isotope analyses revealed that the first-and second-staged granites formed at 154.2±0.6 Ma(MSDW=1.4)and 151.2±0.4 Ma(MSDW=1.5),with zirconε_(Hf)(t)values ranging from-13.1 to-10.5 and from-14.7 to-11.1,respectively.These data suggest that the Tieshanlong granite complex was derived from the partial melting of ancient crustal material.LA-ICP-MS U-Pb dating of wolframite and cassiterite reveals that W-Sn mineralization occurred at 160-150 Ma,which agrees well with the U-Pb dating results of the second-staged granite within analytical errors.The magmatic activity in this ore field can be divided into three stages:175-154 Ma,154-150 Ma and 150-145 Ma.The quartz vein-and skarn-type W-Sn mineralization is closely related to second-staged fine-grained twomica granite,and formed earlier than skarn-type Cu-mineralization.This study establishes a metallogenic model for the Tieshanlong ore field,and this model has important practical significance for identifying concealed W-Sn(-Cu)deposits around other granitic complexes in the Nanling Range.

Nitrogen application regulates antioxidant capacity and flavonoid metabolism,especially quercetin,in grape seedlings under salt stress

Salt stress is a typical abiotic stress in plants that causes slow growth,stunting,and reduced yield and fruit quality.Fertilization is necessary to ensure proper crop growth.However,the effect of fertilization on salt tolerance in grapevine is unclear.In this study,we investigated the effect of nitrogen fertilizer(0.01 and 0.1 mol L^(-1)NH_(4)NO_(3))application on the salt(200 mmol L^(-1)NaCl)tolerance of grapevine based on physiological indices,and transcriptomic and metabolomic analyses.The results revealed that 0.01 mol L^(-1)NH_(4)NO_(3) supplementation significantly reduced the accumulation of superoxide anion(O_(2)^(-)·),enhanced the activities of superoxide dismutase(SOD)and peroxidase(POD),and improved the levels of ascorbic acid(AsA)and glutathione(GSH)in grape leaves compared to salt treatment alone.Specifically,joint transcriptome and metabolome analyses showed that the differentially expressed genes(DEGs)and differentially accumulated metabolites(DAMs)were significantly enriched in the flavonoid biosynthesis pathway(ko00941)and the flavone and flavonol biosynthesis pathway(ko00944).In particular,the relative content of quercetin(C00389)was markedly regulated by salt and nitrogen.Further analysis revealed that exogenous foliar application of quercetin improved the SOD and POD activities,increased the AsA and GSH contents,and reduced the H_(2)O_(2) and O_(2)^(-)·contents.Meanwhile,10 hub DEGs,which had high Pearson correlations(R^(2)>0.9)with quercetin,were repressed by nitrogen.In conclusion,all the results indicated that moderate nitrogen and quercetin application under salt stress enhanced the antioxidant system defense response,thus providing a new perspective for improving salt tolerance in grapes.

Battlefield target intelligence system architecture modeling and system optimization

To address the current problems of poor generality,low real-time,and imperfect information transmission of the battlefield target intelligence system,this paper studies the battlefield target intelligence system from the top-level perspective of multi-service joint warfare.First,an overall planning and analysis method of architecture modeling is proposed with the idea of a bionic analogy for battlefield target intelligence system architecture modeling,which reduces the difficulty of the planning and design process.The method introduces the Department of Defense architecture framework(DoDAF)modeling method,the multi-living agent(MLA)theory modeling method,and other combinations for planning and modeling.A set of rapid planning methods that can be applied to model the architecture of various types of complex systems is formed.Further,the liveness analysis of the battlefield target intelligence system is carried out,and the problems of the existing system are presented from several aspects.And the technical prediction of the development and construction is given,which provides directional ideas for the subsequent research and development of the battlefield target intelligence system.In the end,the proposed architecture model of the battlefield target intelligence system is simulated and verified by applying the colored Petri nets(CPN)simulation software.The analysis demonstrates the reasonable integrity of its logic.

CYP2J2通过激活Notch1途径改善慢性间歇性低氧后心血管损伤的实验研究

目的:探讨细胞色素P450表氧化酶2J2(CYP2J2)对慢性间歇性低氧(CIH)模型大鼠心血管损伤的影响及机制。方法:将50只SD大鼠随机分为对照组、CYP2J2组、CIH组、CIH+CYP2J2组、CIH+CYP2J2+DAPT组,每组10只。CIH组、CIH+CYP2J2组及CIH+CYP2J2+DAPT组大鼠均构建CIH模型;造模成功后,CYP2J2组、CIH+CYP2J2组、CIH+CYP2J2+DAPT组大鼠一次性尾静脉注射携带CYP2J2基因的重组腺病毒;CIH+CYP2J2+DAPT组再通过腹腔注射DAPT。2周后,采用高分辨率小动物超声影像系统测定各组大鼠左室缩短分数(FS)、射血分数(EF)、左室收缩末期容积(LVESV)和左室舒张末期容积(LVEDV);自动生化分析仪检测血清肌酸激酶同工酶(CK-MB)与心肌肌钙蛋白I(cTnI)含量;硝酸还原酶法测定血清一氧化氮(NO)含量;酶联免疫吸附法(ELISA)测定血浆内皮素-1(ET-1)含量;苏木精-伊红(HE)染色观察主动脉及心肌组织形态学变化;末端DNA转移酶dUTP缺口末端标记法(TUNEL)染色观察心肌细胞凋亡情况;生化指标检测试剂盒测定心肌组织超氧化物歧化酶(SOD)活性与丙二醛(MDA)含量;蛋白免疫印迹法(Western Blot)测定心肌组织Notch受体1(Notch1)信号途径相关蛋白表达水平。结果:与CIH组比较,CIH+CYP2J2组大鼠FS和NO水平升高,LVESV、LVEDV及CK-MB、cTnI、ET-1水平均降低,主动脉结构基本清晰,细胞肿大、脱落及血管壁增厚等现象均有所改善,心肌纤维断裂、心肌细胞肿大等现象减轻,心肌组织TUNEL阳性细胞比例减少,SOD活性升高,MDA含量下降,Notch1和Hes1蛋白相对表达量上调,差异均有统计学意义(P<0.05)。与CIH+CYP2J2组比较,CIH+CYP2J2+DAPT组大鼠FS和NO水平降低,LVESV、LVEDV及CK-MB、cTnI、ET-1水平均升高,主动脉组织及心肌组织病理损伤现象显著,心肌组织TUNEL阳性细胞比例增加,SOD活性下降,MDA含量升高,Notch1和Hes1蛋白相对表达量下调,差异均有统计学意义(P<0.05)。结论:CYP2J2可改善CIH大鼠心血管损伤,减少心肌细胞凋亡,并抑制氧化应激水平,该机制可能与激活Notch1途径有关。

Albira SI小动物SPECT-CT对99mTc的检测性能研究

Albira SI小动物单光子发射断层显像-X线计算机体层成像仪(SPECT-CT)是单光子放射性药物临床前研究的先进影像工具,其质量控制及检测性能是图像质量和实验数据可靠性的基本保障。为评价Albira SI SPECT-CT设备应用的真实性、可靠性,采用临床常用单光子核素99mTc对Albira SI小动物SPECT-CT进行季度性质量控制,同时进行测量结果的线性、稳定性、偏差的检测,并初步尝试小动物骨代谢扫描。结果表明,该设备与放射性活度之间线性关系良好,稳定性强,与常用活度测量设备测量结果差异较小。Albira SI小动物SPECT-CT能够准确反映单光子核素99mTc的放射性活度分布,小鼠骨代谢显像效果好,适用于临床前放射性药物研究。本研究中建立的系统研究SPECT-CT性能的方法可为类似设备的操作提供方法学依据。

新质生产力对企业对外直接投资的影响研究——基于二元边际的视角

运用A股上市公司2011—2022年的数据,实证分析新质生产力对企业对外直接投资二元边际的影响,结果发现:新质生产力能够显著提升企业的对外直接投资二元边际,且这一结论在经过一系列稳健性检验及对内生性问题处理后仍然成立;机制检验表明,新质生产力通过放松融资约束、提升ESG表现、增加创新产出提升了企业对外直接投资二元边际;异质性分析表明,新质生产力对企业对外直接投资二元边际的影响在非国有企业、非重污染企业、非高科技企业中更加明显,而新质生产力对企业对外直接投资集约边际的影响在技术密集型和劳动密集型企业中更加明显,对扩展边际的影响在资本密集型企业中更加明显;拓展分析表明,具有海外背景的高管在新质生产力提升企业对外直接投资二元边际的过程中起到了正向调节的作用,同时,新质生产力还增加了企业对外直接投资的概率和在海外市场的收益能力。以上研究率先证实了新质生产力对企业对外直接投资的积极影响,不仅丰富了现有的国际投资与生产力理论,还为中国企业的国际化发展以及中国经济的高质量发展提供理论指导和有益借鉴。

基于改进YOLOv7的变电站设备红外图像识别

高效快速地识别变电站设备是变电站安全状态检测中至关重要的一个环节。针对变电站场景复杂且目标设备尺度不同的特点,在YOLOv7的基础上引入PSA模块,实现局部和全局通道之间的信息交互,提高模型对不同尺度设备的识别精度。再结合PConv和GSConv,建立轻量化网络,在确保模型精度的同时提升检测速度。使用Dyhead将3个感知嵌入一个目标检测头中,提升了目标的检测能力。构建变电站设备红外图像数据集,并进行训练、测试和验证,与原来的YOLOv7算法对比,准确率提升了3%,模型减小了10%,满足高效快速识别变电设备的要求,为后续变电设备故障诊断提供了基础。

益气活血、化痰通络法治疗煤工尘肺缓解期患者的临床研究

目的评价益气活血、化痰通络法治疗对煤工尘肺(CWP)缓解期患者呼吸困难、肺功能、生活质量等指标的改善情况。方法选取2020年10月—2022年9月北京中医药大学房山医院就诊的CWP缓解期患者80例,采用随机数字表法分为观察组与对照组。观察组给予西医常规治疗加益气活血、化痰通络颗粒,1剂/d,分早晚2次口服。对照组给予西医常规治疗加安慰剂,1剂/d,分早晚2次口服。2组疗程均4周,随访8周。对比2组呼吸困难疗效及安全性评价,治疗前后肺功能指标[第1秒用力呼气容积(FEV1)、用力肺活量(FVC)及FEV1/FVC]、6分钟步行距离、中医症状积分。结果治疗4周后,观察组总有效率86.8%,高于对照组的61.5%(P<0.05)。治疗第4周,观察组中医症状积分低于治疗前及对照组(P<0.05);观察组FVC高于治疗前(P<0.05)。治疗第4周、随访第4周,观察组6分钟步行距离均长于治疗前(P<0.05),第4周2组间差异有统计学意义(P<0.05)。在治疗及随访期间,2组患者均未发生不良事件。结论益气活血、化痰通络法联合西医治疗可降低CWP缓解期患者的呼吸困难程度,并对中医症状积分、FVC和6分钟步行距离有改善作用。

Effect of the extrahepatic bile duct anatomy on choledocholithiasis and its clinical significance

BACKGROUND A comprehensive understanding of the extrahepatic bile duct anatomy is vital to guide surgical procedures and perform endoscopic retrograde cholangiography.Anatomical irregularities within the extrahepatic bile duct may increase susceptibility to bile duct stones.AIM To investigate the anatomical risk factors associated with extrahepatic bile ducts in patients diagnosed with choledocholithiasis,with a specific focus on preventing stone recurrence after surgical intervention and endoscopic lithotomy.METHODS We retrospectively analyzed the medical records of 124 patients without choledocholithiasis and 108 with confirmed choledocholithiasis who underwent magnetic resonance cholangiopancreatography examinations at our center between January 2022 and October 2022.Logistic regression analyses were conducted to identify the anatomical risk factors influencing the incidence of common bile duct stones.RESULTS Multivariate logistic regression analysis revealed that several factors independently contributed to choledocholithiasis risk.Significant independent risk factors for choledocholithiasis were diameter of the common hepatic[adjusted odds ratio(aOR)=1.43,95%confidence interval(CI):1.07-1.92,adjusted P value=0.016]and common bile(aOR=1.68,95%CI:1.27-2.23,adjusted P value<0.001)ducts,length of the common hepatic duct(aOR=0.92,95%CI:0.84-0.99,adjusted P value=0.034),and angle of the common bile duct(aOR=0.92,95%CI:0.89–0.95,adjusted P value<0.001).The anatomical features of the extrahepatic bile duct were directly associated with choledocholithiasis risk.Key risk factors include an enlarged diameter of the common hepatic and bile ducts,a shorter length of the common hepatic duct,and a reduced angle of the common bile duct.

Sustainable observations of landfast sea ice in the cryosphere:a case study at the Liaodong Bay,Bohai Sea,North China

Sustainable monitoring of sea ice is crucial for better understanding air-ice-ocean interactions and identifying new processes.However,it is an expensive process particularly for the polar cryosphere environment.The seasonal ice-covered sea area can be used as a test bed for cryosphere-related process studies due to convenient access and conduction of field work,and the seasonal regime variation of the Arctic sea ice resulting from climate changes.In this paper,a small landfast sea ice monitoring program has been carried out for four consecutive seasons at Jiangjunshi Port,the Bohai Sea,North China,analyzing the temperature and salinity of air,ice and ocean and discussing the influence on mechanical properties.The effect of air temperature on sea ice temperature is focused.During low-temperature periods,the maximum correlation coefficient between air temperature and ice temperature,along with temperature fluctuation within ice,decreases as ice depth increases.Ice salinity was measured using ice core sampling and ice crumb sampling,with ice crumb salinity twice larger compared to ice core sampling when the ice temperature is−3℃.Ice salinity variations with ice temperature and the salinity profiles were fitted.Analysis of the profiles of under-ice seawater salinity reveals the presence of a high-salinity layer near the bottom of sea ice during the initial stage of sea ice growth.Based on the dynamic changes in sea ice temperature and sea ice salinity,this study evaluates the mechanical properties of sea ice,with the fitting determination coefficients of the obtained parameterized formulas significantly better than those reported in current research.

基于LIBS技术在线监测熔融铝水中的元素成分

在辽宁忠旺集团有限公司的熔铸厂,利用自主研制的LIBS液态金属成分在线分析仪对熔融铝水的成分进行了在线监测.研究了通入探杆中氩气的最佳流量以及探测深度与氩气波动的规律,发现氩气流量为1~1.4L/min时,光谱强度最强,探测深度位于氩气压力波动范围在±300Pa,并且压力波动有规律时的位置,各元素浓度稳定性好;利用实验室分析得到的固样数据对设备进行了标定,长时间测试得到的在线监测结果为:Si、Fe、Cu、Mn、Cr的重复精度都小于2%;浓度在0.1%~1%之间的Si、Fe、Mg的测量偏差都小于0.01%,浓度低于0.1%的Cu、Mn、Cr的测量偏差都小于0.001%;探杆多次升降浓度测量的稳定性小于3%.LIBS液态金属成分分析仪的测量重复精度、测量偏差以及多次升降测量的稳定性都能满足工业现场要求,完全可以实现实时、在线监测熔融铝水的成分.