Modeling and Control of Head of the Underwater Snake-like Robot Swimming

In order to solve oscillation of head of the underwater snake-like robot,the Central Pattern Generator( CPG)-based control scheme with head-controller was presented. The Kane dynamic model was constructed to be processed with a commercial package MotionGenesis Kane 5. 3,to which the proposed control scheme was applied. The relation between CPG parameters and orientation offset of head was investigated. The target orientation of head-controller was calculated through a convenient method. The advantage of this control scheme is that the head of the underwater snake-like robot remains in the forward direction during swimming. To prove the feasibility of the proposed methodology,two basic motion patterns,swimming along the straight line and swimming along the curved path,had been implemented in our simulation platform. The results showed that the simulation platform can imitate the swimming of the underwater snake-like robot and the head of the underwater snake-like robot remains in a fixed orientation directed towards the target. The oscillation of head's orientation is inhibited effectively.

Diode-pumped Kerr-lens mode-locked Ti: sapphire laser with broad wavelength tunability

We report a direct blue-diode-pumped wavelength tunable Kerr-lens mode-locked Ti: sapphire laser.Central wavelength tunability as broad as 89 nm(736-825 nm) is achieved by adjusting the insertion of the prism.Pulses as short as 17 fs are generated at a central wavelength of 736 nm with an average output power of 31 mW.The maximum output power is 46.8 mW at a central wavelength of 797 nm with a pulse duration of 46 fs.

Energy evolution and water immersion‑induced weakening in sandstone roof of coal mines

The instability of underground spaces in abandoned coal mines with water-immersed rocks is one of the main hazards hindering the geothermal energy use and ecological restoration of post-mining areas.This study conducted graded cyclic loading–unloading tests of fve groups of sandstone samples with diferent water contents.The evolution of input,elastic,dissipated,damping,and plastic energies were explored,considering the damping efect.The normalized plastic energy serves to characterize the damage evolution of sandstone samples,whose failure characteristics were analyzed from both the macroscopic and microscopic perspectives.X-ray difraction technique and scanning electron microscopy were used to reveal the softening mechanism of sandstone.The results show that under graded cyclic loading,input energy,elastic energy,and dissipated energy all increase gradually,and the fraction of elastic energy increases gradually at frst and then tends to stabilize.The variation in the fraction of dissipated energy is opposite to that of elastic energy.In each cycle,the input energy is stored primarily in the form of elastic energy,whereas the dissipated energy is used primarily to overcome the damping of sandstone.When the normalized number of cycles approached unity,the plastic energy fraction sharply increases,while that of the dampening energy drops abruptly.With increasing water content,the efect of pore water on the lubrication,the water wedge,and dissolution of mineral particles becomes more obvious,reducing the elastic-storage limit of sandstone,meanwhile the sandstone damage factor increases signifcantly under the same cycle and the failure mode changes from brittle to ductile.

Rare giant corneal keloid presenting 26 years after trauma:A case report

BACKGROUND Corneal keloid is a rare clinical disease with an unknown etiology,which is easily misdiagnosed.Surgery is the most effective treatment but is rarely reported in the literature.Herein,we report the clinical features,histopathology,and surgical outcome of a giant corneal keloid with trophoblastic vessels and discuss the genesis of the mass.CASE SUMMARY A 36-year-old young man was admitted to the hospital because of a large mass on the surface of the left cornea.The patient had suffered an injury to his left eye at the age of 6-years-old;however,as the injury did not cause cornea perforation,he did not undergo treatment.Slit lamp exam showed a large,elevated,opaque lesion that covered the entire cornea and protruded from the surface of the eyeball.Anterior segment optical coherence tomography(AS-OCT) revealed a lesion of irregular density involving the anterior stroma.We suspected a secondary corneal fibroproliferative mass based on the clinical history,and slit lamp and AS-OCT findings.The patient subsequently underwent a superficial keratectomy and keratoplasty,and the final diagnosis of corneal keloid was confirmed by intraoperative histopathological examination.CONCLUSION Non-penetrating corneal trauma damages corneal epithelium basement membrane,initiating stromal fibrosis and causing corneal keloids.AS-OCT and biopsy confirm diagnosis.

Adaptive Swimming of Underwater Snake-like Robot in Different Underwater Environment

Hydrodynamic force is an important factor that affects the performance of underwater vehicle.Adapting to the current underwater environment by changing its shape is an important feature of underwater snake-like robots(USLR).An experiment was implemented to verify the swimming along the straight line of USLR.A simulation platform is also established for the analysis of the swimming of USLR.To figure out adaptive swimming of USLR to different underwater environments,the relationships between CPG parameters and maximum swimming speed have been discussed,and the switching between different swimming modes has been implemented.

Head Orientation Stability of Underwater Snake-Like Robot Swimming

In prior research,the orientation of head of the snake-like robot is changed according to the sinusoidal wave. To solve this problem,we propose Central Pattern Generator( CPG)-based control scheme with head-controller to stabilize the head of the underwater snake-like robot. The advantage of the CPG-based control scheme with head-controller is that the head of the underwater snake-like robot is direct to the target orientation during swimming. The relation between CPG parameters and orientation stability of head is discussed.The adaptation of the proposed method to environment changes is tested. The influences of CPG parameters and hydrodynamic forces on the orientation offset of head are investigated. The target orientation( the input of headcontroller) with an experimental optimization is calculated through a convenient method. To prove the feasibility of the proposed methodology,the different swimming modes have been implemented in our simulation platform.The results show that the oscillation of head's orientation is inhibited effectively,and the proposed method has strong adaptation to environment and CPG parameters changes.

火焰原子吸收光谱测定葡萄糖酸锌口服液中锌含量

“火焰原子吸收光谱”是本科生仪器分析实验教学中的重要实验之一。原子吸收光谱用于实际样品中某一特定元素的定量测定,具有测定准确度高、精密度高和选择性好等优点。葡萄糖酸锌口服液是生活中常见的口服补锌类非处方药,通过本科生自主实验,建立火焰原子吸收实验方法,测定葡萄糖酸锌口服液中锌含量,方法简便、易于操作。通过该自主实验,培养学生利用课堂所学理论知识解决实际问题的能力,实现“学以致用,用以促学”的育人目标。

Degradable magnesium alloy suture promotes fibrocartilaginous interface regeneration in a rat rotator cuff transosseous repair model

Despite transosseous rotator cuff tear repair using sutures is widely accepted for tendon-bone fixation,the fibrocartilaginous enthesis regeneration is still hardly achieved with the traditional sutures.In the present work,degradable magnesium(Mg)alloy wire was applied to suture supraspinatus tendon in a rat acute rotator cuff tear model with Vicryl Plus 4±0 absorbable suture as control.The shoulder joint humerus-supraspinatus tendon complex specimens were retrieved at 4,8,and 12 weeks after operation.The Mg alloy suture groups showed better biomechanical properties in terms of ultimate load to failure.Gross observation showed that hyperplastic response of the scar tissue at the tendon-bone interface is progressively alleviated over time in the both Mg alloy suture and Vicryl suture groups.In the histological analysis,for Mg alloy suture groups,chondrocytes appear to proliferate at 4 weeks postoperatively,and the tendon-bone interface showed an orderly structural transition zone at 8 weeks postoperatively.The collagenous fiber tended to be aligned and the tendon-bone interlocking structures apparently formed,where transitional structure from unmineralized fibrocartilage to mineralized fibrocartilage was closer to the native fibrocartilaginous enthesis.In vivo degradation of the magnesium alloy wire was completed within 12 weeks.The results indicated that Mg alloy wire was promising as degradable suture with the potential to promotes fibrocartilaginous interface regeneration in rotator cuff repair.

PD-1/PD-L1抑制剂联合贝伐珠单抗在晚期三阴性乳腺癌中的应用价值

目的探究程序性死亡受体1(PD-1)/程序性死亡受体-配体1(PD-L1)抑制剂联合贝伐珠单抗在晚期三阴性乳腺癌(TNBC)中的应用效果。方法选择本院2020年1月~2021年12月诊治的102例晚期TNBC患者,按治疗方式不同将其设为47例对照组(PD-1/PD-L1抑制剂治疗)与55例研究组(PD-1/PD-L1抑制剂联合贝伐珠单抗治疗)。比较两组疗效、不良反应及预后情况。结果研究组总体客观缓解率36.36%,比对照组17.02%高(P<0.05)。两组不良反应总发生率对比无差异(P>0.05)。研究组无进展生存期比对照组高(P<0.05);两组复发率对比无差异(P>0.05)。结论PD-1/PD-L1抑制剂联合贝伐珠单抗在晚期三阴性乳腺癌中的疗效确切,可改善患者短期预后,且安全性可控,临床应用价值较高。

Ultrahard X-ray multifunctional application beamline at the SSRF

The ultrahard X-ray multifunctional application beamline(BL12SW)is a phase-II beamline project at the Shanghai Syn-chrotron Radiation Facility.The primary X-ray techniques used at the beamline are high-energy X-ray diffraction and imaging using white and monochromatic light.The main scientific objectives of ultrahard X-ray beamlines are focused on two research areas.One is the study of the structural properties of Earth’s interior and new materials under extreme high-temperature and high-pressure conditions,and the other is the characterization of materials and processes in near-real service environments.The beamline utilizes a superconducting wiggler as the light source,with two diamond windows and SiC discs to filter out low-energy light(primarily below 30 keV)and a Cu filter assembly to control the thermal load entering the subsequent optical components.The beamline is equipped with dual monochromators.The first was a meridional bending Laue monochromator cooled by liquid nitrogen,achieving a full-energy coverage of 30-162 keV.The second was a sagittal bending Laue monochromator installed in an external building,providing a focused beam in the horizontal direction with an energy range of 60-120 keV.There were four experimental hutches:two large-volume press experimental hutches(LVP1 and LVP2)and two engineering material experimental hutches(ENG1 and ENG2).Each hutch was equipped with various near-real service conditions to satisfy different requirements.For example,LVP1 and LVP2 were equipped with a 200-ton DDIA press and a 2000-ton dual-mode(DDIA and Kawai)press,respectively.ENG1 and ENG2 provide in situ tensile,creep,and fatigue tests as well as high-temperature conditions.Since June 2023,the BL12SW has been in trial operation.It is expected to officially open to users by early 2024.

Dietary manganese supplementation inhibits abdominal fat deposition possibly by regulating gene expression and enzyme activity involved in lipid metabolism in the abdominal fat of broilers

Excessive abdominal fat deposition seriously restricts the production efficiency of broilers.Several studies found that dietary supplemental manganese(Mn)could effectively reduce the abdominal fat deposition of broilers,but the underlying mechanisms remain unclear.The present study aimed to investigate the effect of dietary supplementation with the inorganic or organic Mn on abdominal fat deposition,and enzyme activity and gene expression involved in lipid metabolism in the abdominal fat of male or female broilers.A total of 4201-d-old AA broilers(half males and half females)were randomly allotted by body weight and gender to 1 of 6 treatments with 10 replicates cages of 7 chicks per cage in a completely randomized design involving a 3(dietary Mn addition)×2(gender)factorial arrangement.Male or female broilers were fed with the Mn-unsupplemented basal diets containing 17.52 mg Mn kg^(-1)(d 1-21)and 15.62 mg Mn kg^(-1)(d 22-42)by analysis or the basal diets supplemented with 110 mg Mn kg^(-1)(d 1-21)and 80 mg Mn kg^(-1)(d 22-42)as either the Mn sulfate or the Mn proteinate with moderate chelation strength(Mn-Prot M)for 42 d.The results showed that the interaction between dietary Mn addition and gender had no impact(P>0.05)on any of the measured parameters;abdominal fat percentage of broilers was decreased(P<0.003)by Mn addition;Mn addition increased(P<0.004)adipose triglyceride lipase(ATGL)activity,while Mn-Prot M decreased(P<0.002)the fatty acid synthase(FAS)activity in the abdominal fat of broilers compared to the control;Mn addition decreased(P<0.009)diacylglycerol acyltransferase 2(DGAT2)mRNA expression level and peroxisome proliferator-activated receptor γ(PPARγ)mRNA and protein expression levels,but up-regulated(P<0.05)the ATGL mRNA and protein expression levels in the abdominal fat of broilers.It was concluded that dietary supplementation with Mn inhibited the abdominal fat deposition of broilers possibly via decreasing the expression of PPARγand DGAT2 as well as increasing the expression and activity of ATGL in the abdominal fat of broilers,and Mn-Prot M was more effective in inhibiting the FAS acitivity.

虚拟现实技术在“非遗”保护与传承中应用策略研究

非物质文化遗产承载着深厚的历史与丰富的民族智慧,但在现代社会发展浪潮中,非遗的保护与传承正面临前所未有的挑战。文章从我国非遗保护工作的发展困境出发,以虚拟现实技术为主要手段,探讨了“非遗”保护与传承中虚拟现实技术的具体应用方法,如三维重建、全景拍摄以及VR全景纪录片制作等,旨在为非物质文化遗产的保护与传承提供有力的支持。

A Formal Model for Analyzing Fair Exchange Protocols Based on Event Logic

Fair exchange protocols play a critical role in enabling two distrustful entities to conduct electronic data exchanges in a fair and secure manner.These protocols are widely used in electronic payment systems and electronic contract signing,ensuring the reliability and security of network transactions.In order to address the limitations of current research methods and enhance the analytical capabilities for fair exchange protocols,this paper proposes a formal model for analyzing such protocols.The proposed model begins with a thorough analysis of fair exchange protocols,followed by the formal definition of fairness.This definition accurately captures the inherent requirements of fair exchange protocols.Building upon event logic,the model incorporates the time factor into predicates and introduces knowledge set axioms.This enhancement empowers the improved logic to effectively describe the state and knowledge of protocol participants at different time points,facilitating reasoning about their acquired knowledge.To maximize the intruder’s capabilities,channel errors are translated into the behaviors of the intruder.The participants are further categorized into honest participants and malicious participants,enabling a comprehensive evaluation of the intruder’s potential impact.By employing a typical fair exchange protocol as an illustrative example,this paper demonstrates the detailed steps of utilizing the proposed model for protocol analysis.The entire process of protocol execution under attack scenarios is presented,shedding light on the underlying reasons for the attacks and proposing corresponding countermeasures.The developedmodel enhances the ability to reason about and evaluate the security properties of fair exchange protocols,thereby contributing to the advancement of secure network transactions.

A Hybrid Approach for Predicting the Remaining Useful Life of Bearings Based on the RReliefF Algorithm and Extreme Learning Machine

Accurately predicting the remaining useful life(RUL)of bearings in mining rotating equipment is vital for mining enterprises.This research aims to distinguish the features associated with the RUL of bearings and propose a prediction model based on these selected features.This study proposes a hybrid predictive model to assess the RUL of rolling element bearings.The proposed model begins with the pre-processing of bearing vibration signals to reconstruct sixty time-domain features.The hybrid model selects relevant features from the sixty time-domain features of the vibration signal by adopting the RReliefF feature selection algorithm.Subsequently,the extreme learning machine(ELM)approach is applied to develop a predictive model of RUL based on the optimal features.The model is trained by optimizing its parameters via the grid search approach.The training datasets are adjusted to make them most suitable for the regression model using the cross-validation method.The proposed hybrid model is analyzed and validated using the vibration data taken from the public XJTU-SY rolling element-bearing database.The comparison is constructed with other traditional models.The experimental test results demonstrated that the proposed approach can predict the RUL of bearings with a reliable degree of accuracy.

纳米纤维素/聚己内酯的等温结晶动力学

利用差示扫描量热仪(DSC)研究了聚己内酯(PCL)与纳米纤维素复合材料的等温结晶动力学,采用了Avrami理论来解析结晶过程中成核和生长的动力学。研究结果表明,纳米纤维素(CNC)诱导PCL异相成核能有效提高PCL基体的结晶速率。在等温结晶过程中,相对分子质量为300和3000的聚乙烯亚胺(PEI)修饰的CNC(CNC-P1、CNC-P2)能够将PCL的半结晶时间由5.19 s降低至1.70和2.07 s。为研究修饰后CNC对PCL结晶结构的影响,结合Thomson-Gibbs方程和Lauritzen-Hoffman方程计算了PCL的折叠表面自由能和片晶厚度,结果表明,加入修饰后的CNC导致PCL的折叠表面自由能显著降低,分别由0.024 J/m^(2)降低至0.179 J/m^(2)和0.020 J/m^(2),片晶厚度由18.6 nm增大至20.2 nm和18.9 nm。修饰后的CNC对于PCL的等温结晶动力学及结晶特性均有显著的影响。

掌上电脑终端经脑心健康管理师为伴高血压病的脑梗死患者行健康教育的应用

目的探讨脑心健康管理师使用移动护理信息系统的掌上电脑(PDA)终端在伴高血压病的脑梗死患者行健康教育的应用效果。方法选择2020年7月—2021年10月本科收治的104例伴高血压病的脑梗死患者作为研究对象,采用随机数表法分为实验组和对照组两组,每组各52例。对照组按常规方式进行健康宣教,观察组为脑心健康管理师应用移动护理信息系统的PDA终端进行床旁健康宣教。比较两组患者的健康知识水平、生活自理能力、满意度、神经功能损害及预后情况。结果护理后,两组患者MRS评分比较,差异无统计学意义(P>0.05),但两组患者护理干预前后MRS评分比较,差异均具有统计学意义(P<0.05);护理后,两组患者NIHSS评分比较,差异无统计学意义(P>0.05),但两组患者护理干预前后NIHSS评分比较,差异均具有统计学意义(P<0.05);护理后,两组患者Barthel评分比较,差异无统计学意义(P>0.05),但两组患者护理干预前后Barthel评分比较,差异均具有统计学意义(P<0.05);干预后,两组患者的饮食知识、药物安全、生活起居、基本知识、康复知识及总分比较,差异具有统计学意义(P<0.05);实验组患者的满意度高于对照组,差异有统计学意义(P<0.05)。结论脑心健康管理师充分应用移动护理信息系统PDA终端行患者健康教育,可明显提升患者的满意度及健康素养,不仅为患者提供优质护理服务,也为出院后脑卒中二级预防提供依据。

乙酰水杨酸的制备实验教学改革

以水杨酸钠和乙酰氯为原料合成乙酰水杨酸,反应温和,反应条件易控制。正交实验重点考察了反应物摩尔比、反应温度、反应时间及硫酸的用量等条件对产率的影响。实验表明,乙酰水杨酸合成的最佳实验条件是:乙酰氯和水杨酸钠的摩尔比为3∶1,反应温度80℃,硫酸用量为2 d,反应时间为20 min,在此条件下产率可达75.5%。该实验可为有机化学实验教学改进提供理论数据。

不同种植年限猕猴桃园土壤微生物功能多样性研究

陕西秦岭北麓是世界上最大的猕猴桃生产基地,长期相对单一的果树种植方式导致不同种植年限果园土壤微生态环境差异。研究猕猴桃园土壤微生物功能多样性随种植年限的变化特征,为果园土壤科学管理提供参考。采集不同种植年限猕猴桃根际土壤,应用平板菌落计数法和Biolog-Eco法研究土壤微生物的数量、种群以及功能多样性,并对土壤微生物功能多样性与土壤养分的相关性进行分析。结果显示,猕猴桃园土壤可培养微生物以细菌为主,其次是放线菌,真菌数量最少。随着种植年限的增加,细菌和放线菌数量显著降低,而真菌数量显著升高。微生物平均颜色变化率(average well-color development,AWCD)、微生物群落Shannon-Wiener指数(H′)、Simpson指数(D)及McIntosh指数(U)均随种植年限的增加而显著降低。主成分分析显示,不同种植年限猕猴桃园土壤微生物碳源利用特征明显不同,0~5 a、5~10 a和10~20 a的猕猴桃园土壤微生物群落分别被划分在载荷图的第一、第四和第三象限。猕猴桃园土壤微生物对糖类、氨基酸类和酯类的利用率相对较高,而对醇类、胺类和酸类的利用率相对较低。对第1主成分贡献大的碳源(|r|≥0.5)有11种,其中糖类占36%,氨基酸类和酯类均占18%。土壤微生物功能多样性与土壤养分相关性分析表明,土壤微生物功能多样性与土壤有机质正相关,与有效磷和速效钾负相关。结果表明,随种植年限的增加,猕猴桃园土壤微生物的数量和结构发生变化,微生物功能多样性降低,对碳源利用能力降低。鉴于土壤微生物功能多样性与土壤养分的相关性,应合理加大有机肥施用量,适量减少有效磷和速效钾的施用量。

猕猴桃溃疡病菌拮抗菌的筛选、鉴定及其对植物病原真菌的抗性

从野生银杏中分离、筛选抗猕猴桃溃疡病内生细菌,并明确其对常见植物真菌病害的抑菌谱。采用“三步法”分离银杏内生细菌,并以猕猴桃溃疡病病原菌(Pseudomonas syringae pv.actinidiae,Psa)作为指标菌筛选拮抗菌;结合菌落形态特征、生理生化特征及16S rRNA基因序列对拮抗菌进行鉴定;开展盆栽防治实验研究其对猕猴桃溃疡病的防治效率,并应用平板对峙法研究其对多种植物病原真菌的拮抗作用。结果共得到7株对Psa具有拮抗活性的内生细菌,其中,以菌株MA23的拮抗活性最为显著,鉴定为蜡样芽孢杆菌。MA23发酵液上清对猕猴桃溃疡病的盆栽防治效率为93.6%,同时其对多种病原真菌也具有拮抗活性。从银杏中筛选到一株对Psa具有较好拮抗活性的内生蜡样芽孢杆菌MA23,其对多种植物病原真菌也具有拮抗活性。

高性能水泥基灌浆料配合比设计的实践与验证

使用Alfred模型进行高性能水泥基灌浆料配合比设计,研究并优化了其堆积曲线公式系数q。同时利用制备超高性能混凝土理论与中心质假说,通过在普通水泥中加入超细矿粉、硅灰、膨胀剂等矿物掺和料,寻求适当的砂胶比与混合物颗粒粒径分布,提高胶凝体系的密实度,增强胶凝体系的流动度与稳定性。进而制备出一种无泌水、流动度佳、早强高强的高性能水泥基灌浆料。总结了一种具有普遍适用性的、快速准确的高性能水泥基灌浆料配合比设计思路。