Research and Application of"Soft"Devices for Realizing Servo Amplification

This article analyzes and discusses the working principle and problems encountered by various servo amplification devices used in the on-site continuous adjustment system,analyzes and discusses the application of the servo mechanism,and analyzes the mechanism of the servo device's implementation of the"positioning"func-tion on the control device.Intended to guide the continuous adjustment process in controlling the function/accuracy of actuator equipment and application debugging,ensuring the safe and stable operation of production equipment and facilities.

Smart and fast reinforcement design for anti-dip bedding rock slopes

Rock slopes are usually reinforced by a number of rock bolts due to the high efficiency and low price.However,where should the rock bolts be installed is still a troublesome issue.For anti-dip bedding rock slopes(ABRSs),the installation position of rock bolts is a controlling factor that determines the reinforcement effect.In this work,a theoretical method is firstly proposed for assessing the stability of ABRSs reinforced by rock bolts using a limit equilibrium model.A comparison of theoretical calculations and numerical results was conducted to test the correctness of the theoretical method.Based on the stability assessment of ABRSs,we introduce adaptive moment estimation method(Adam)to optimize the installation location of rock bolts.Using Adam optimizer,the optimal layout of rock bolts with the maximum factor of safety can be determined,and the factor of safety of the slope increases by about 25%using the same amount of rock bolts but with different installation locations.The proposed method enables the fast stability analysis and supporting design for reinforced ABRSs,which paves the way to smart supporting design of slopes.

西南丘陵山区马铃薯机械化收获技术与装备研究进展

西南丘陵山区是我国马铃薯种植的重要区域。然而,在西南山区,由于地块面积小,坡度大,路面崎岖,同时土壤板结、黏重等原因,导致马铃薯生产机械化程度低下,成为制约我国马铃薯产业发展的瓶颈。重点介绍了马铃薯收获机械的核心技术和国内外马铃薯收获装备的研究进展,并对今后丘陵山区马铃薯收获的发展趋势和研究方向提出建议,即加强西南丘陵山区农田的基础建设,着重于农机农艺的结合;加强对丘陵山区适用马铃薯收获机的研究,制造适合丘陵山区的装备;加强政策扶持,设置激励机制;加强机械化收获示范区建设,打造宜机示范区。。

妈富隆联合二甲双胍对多囊卵巢综合征患者降钙素原、免疫功能及氧化应激水平的影响

目的:观察妈富隆联合二甲双胍对多囊卵巢综合征(PCOS)患者降钙素原(PCT)、免疫功能及氧化应激水平的影响。方法:收集2016年6月—2017年6月本院收治的PCOS患者80例,根据随机数字表法分为对照组与观察组各40例。对照组给予妈富隆治疗,观察组在对照组治疗基础上给予二甲双胍治疗。两组均治疗3个生理周期。比较两组患者临床疗效;检测两组患者治疗前后血清T淋巴细胞、PCT、丙二醛(MDA)、超氧化物歧化酶(SOD)水平。结果:对照组总有效率(67.5%)低于观察组(87.5%)(P<0.05),不良反应率两组比较无差异(P>0.05)。两组患者血清中T淋巴细胞、PCT、MDA及SOD水平治疗前无明显差异(P>0.05),治疗后CD3^+、CD4^+、CD4^+/CD8^+、SOD水平均升高且观察组高于对照组,CD8^+、PCT、MDA水平均降低且观察组低于对照组(均P<0.05)。结论:妈富隆联合二甲双胍治疗PCOS具有较好的临床疗效,可显著改善患者免疫功能,缓解炎症反应状态,降低机体氧化应激程度。

Wnt/β-catenin信号转导通路在瘢痕疙瘩形成中的作用机制研究

目的了解Wnt/β-catenin信号转导通路在瘢痕疙瘩原代成纤维细胞中关键蛋白和m RNA水平,探讨其在瘢痕疙瘩形机制中的作用。方法采用组织块培养法进行原代成纤维细胞培养,通过Western Blot和RT-PCR法分别检测正常皮肤以及瘢痕疙瘩成纤维细胞中Wnt/β-catenin信号转导通路中相关信号分子Wnt5a、β-catenin、GSK-3β、p-GSK-3β蛋白和Wnt5a、β-catenin、GSK-3βm RNA水平,比较两者之间差异。结果与正常皮肤相比,瘢痕疙瘩成纤维细胞中Wnt5a、β-catenin、p-GSK-3β蛋白及Wnt5a、β-catenin m RAN水平增高(P<0.05),GSK-3β蛋白及m RNA表达水平无明显变化。结论在瘢痕疙瘩形成过程中,Wnt5a、β-catenin m RAN上调并导致Wnt5a、β-catenin蛋白水平增高以及GSK-3β蛋白磷酸化导致p-GSK-3β增高可能在瘢痕疙瘩的形成机制中起着重要作用。

Seven-day triple therapy is a better choice for Helicobacter pylori eradication in regions with low antibiotic resistance

AIM: To investigate whether 7-d triple therapies are still valid in populations with low levels of resistance.METHODS: A total of 1106 Helicobacter pylori(H. pylori)-positive patients were divided into three groups,each of which received one type of 7-d triple therapy. Therapeutic outcomes of the patients were assessed by the 13C-urea breath test at 8 wk after treatment. The susceptibility of H. pylori to antibiotics was determined by an agar-dilution method. Data analysis was performed by χ2 tests.RESULTS: The eradication rates in groups A,B and C were 90.71%(332/366),90.46%(313/346) and 90.87%(189/208),respectively(P = 0.986). The resistance rates were 8.91% for clarithromycin,14.78% for levofloxacin and 0% for amoxicillin. The eradication rate was significantly different between clarithromycin-and levofloxacin-resistant patients(P < 0.05) in group A. Patients whose treatment failed in group A also had a higher clarithromycin resistance rate than did successive patients(P = 0.034). However,levofloxacin resistance had no obvious influence on the eradication rate. Furthermore,three main antibiotics(clarithromycin,levofloxacin and amoxicillin) had lower DID(defined daily dose per 1000 inhabitants per day) in this city.CONCLUSION: Clarithromycin resistance is the main reason for the failure of 7-d triple therapy. In populations with low levels of resistance,a 7-d triple therapy is a viable choice. The choice of therapy should not be influenced by conditions in high antibiotic resistance regions.

Partners of patients with ulcerative colitis exhibit a biologically relevant dysbiosis in fecal microbial metacommunities

AIM To investigate alterations in the fecal microbiome using 16 S r RNA amplicon sequencing in couples in the same cohabitation environment.METHODS Fecal samples were collected from eight ulcerative colitis(UC) patients and their healthy partners at Lishui People's Hospital, Zhejiang Province, China. DNA was extracted and the variable regions V3 and V4 of the 16 S r RNA genes were PCR amplified using a two-step protocol. Clear reads were clustered into operational taxonomic units(OTUs) at the 97% sequence similarity level using UCLUST v1.2.22. The Wilcoxon rank-sumtest(R v3.1.2) was used to compare inter-individual differences. Differences with a P value < 0.05 were considered statistically significant.RESULTS Fecal microbial communities were more similar among UC patients than their healthy partners(P = 0.024). UC individuals had a lower relative abundance of bacteria belonging to the Firmicutes, especially Blautia, Clostridium, Coprococcus and Roseburia(P < 0.05). Microbiota dysbiosis was detected in UC patients and their healthy partners. Relevant genera included Akkermansiam, Bacteroides, Escherichia, Lactobacillales, Klebsiella and Parabacteroides. The enriched pathways in fecal samples of UC patients were related to lipid and nucleotide metabolism. Additionally, the pathways involved in membrane transport and metabolism of cofactors and vitamins were more abundant in the healthy partners.CONCLUSION Our results suggested that the microbial composition might be affected in healthy partners cohabiting with UC patients, especially in terms of microbiota dysbiosis.

70岁以上老年急性胰腺炎患者的临床特征分析

目的探讨≥70岁老年急性胰腺炎(AP)患者的临床特征。方法选取2013年6月—2018年3月于西南医科大学附属医院住院的342例≥70岁老年AP患者的病历资料作为实验组,随机选择同期年龄15～59岁的AP患者684例作为对照组,分析两组患者的病历资料。结果两组男女比例、性别比较,差异有统计学意义(P <0.05)。实验组的首位病因为胆道疾病(54.97%),对照组的首位病因为高脂血症(44.01%)。实验组血淀粉酶、谷丙转氨酶、谷草转氨酶、直接胆红素及肌酐水平高于对照组(P<0.05),血钙、总胆固醇、甘油三酯、白蛋白水平低于对照组(P<0.05)。实验组合并高血压、冠状动脉粥样硬化性心脏病比例高于对照组(P <0.05)。相比对照组,实验组更易发生呼吸衰竭、肾衰竭、胆道感染及肺部感染(P <0.05)。实验组总病死率及重症急性胰腺炎病死率高于对照组(P <0.05)。结论年龄≥70岁老年AP患者女性比例较高,主要病因为胆道疾病,其并发症发生率及病死率高,了解其临床特征有助于制定有针对性的诊疗方案。

Ninety-four thousand-case retrospective study on antibacterial drug resistance of Helicobacter pylori

BACKGROUND The resistance rate to antibacterial drugs is the key inhibitor of Helicobacter pylori(H.pylori)eradication treatment.AIM To evaluate the prevalence and drug resistance of H.pylori based on big data.METHODS Gastric mucosal specimens were collected from naive patients undergoing upper gastrointestinal endoscopy for H.pylori culture and antimicrobial susceptibility testing(AST),including clarithromycin,levofloxacin,metronidazole and amoxicillin.Every 10 years of age was grouped as an age group.The H.pylori infection and resistance were explored based on the age group and gender.RESULTS The number of H.pylori-positive specimen was 94509 in 283823 gastric mucosal specimens,with an infection rate of 33.30%.The infection rate increased with age,and males had a higher infection rate than females.The average resistance rate of H.pylori to amoxicillin and metronidazole was 0.21%and 93.72%,which remained stable.The average resistance rate to clarithromycin was 23.99%with an increasing trend from 14.43%to 38.24%.The average resistance rate to levofloxacin was 30.29%,which increased from 17.07%to 39.42%and mostly stabilized after 2017.The resistance rate of H.pylori increased with age,except amoxicillin.H.pylori in females are at higher risk of resistance to metronidazole but not to amoxicillin,regardless of the age group.Meanwhile,H.pylori in females are at higher risk of resistance to levofloxacin and clarithromycin in the 21-50 age group.The single,dual,triple and quadruple-drug resistance rate was 54.59%,29.03%,11.71%and 0.11%,respectively.CONCLUSION The resistance of H.pylori in Taizhou city is serious.Guided by the consensus report,individualized treatment based on AST is recommended.

Improved Evaluation of BBR and Collisional Frequency Shifts of NIM-Sr2 with 7.2×10^(-18)Total Uncertainty

NIM-Sr2 optical lattice clock has been developed on the Changping campus of National Institute of Metrology(NIM).Considering the limitations in NIM-Sr1,several improved parts have been designed including a differential pumping stage in the vacuum system,a permanent magnet Zeeman slower,water-cooled anti-Helmholtz coils,an extended viewport for Zeeman slower,etc.A clock laser with a short-time stability better than 3×10^(-16)is realized based on a self-designed 30-cm-long ultra-low expansion cavity.The systematic frequency shift has been evaluated to an uncertainty of 7.2×10^(-18),with the uncertainty of BBR shift and the collisional frequency shift being an order of magnitude lower than the last evaluation of NIM-Sr1.

Simulation of the effects of different substrates, temperature,and substrate roughness on the mechanical properties of Al_2O_3 coating as tritium penetration barrier

Residual thermal stress in the system is a serious problem that affects the application of tritium permeation barrier coatings in fusion reactors. The stress not only determines the adhesion between coating and substrate, but also changes the properties of the material. In this study,finite element analysis was used to investigate the relationship between the residual thermal stress and the mechanical properties of Al_2O_3 tritium penetration barrier systems. Moreover, the residual thermal stress influenced by factors such as different substrates, temperature, and substrate roughness was also analyzed. The calculation showed that the hardness and elastic modulus increased with increasing compressive stress. However, the hardness and elastic modulus decreased with increasing tensile stress. The systems composed of Al_2O_3 coatings and different substrates exhibited different trends in mechanical properties. As the temperature increased, the hardness and the elastic modulus increased in an Al_2O_3/316 L stainless steel system; the trend was opposite in an Al_2O_3/Si system.Apart from this, the roughness of the substrate surface in the system could magnify the change in hardness and elastic modulus of the coating. Results showed that all these factors led to variation in the mechanical properties of Al_2O_3 tritium permeation barrier systems. Thus, thedetailed reasons for the changes in mechanical properties of these materials need to be analyzed.

Explosive Electric Actuator and Control for Legged Robots

Unmanned systems such as legged robots require fast-motion responses for operation in complex envi-ronments.These systems therefore require explosive actuators that can provide high peak speed or high peak torque at specific moments during dynamic motion.Although hydraulic actuators can provide a large force,they are relatively inefficient,large,and heavy.Industrial electric actuators are incapable of providing instant high power.In addition,the constant reduction ratio of the reducer makes it difficult to eliminate the tradeoff between high speed and high torque in a given system.This study proposes an explosive electric actuator and an associated control method for legged robots.First,a high-power-density variable transmission is designed to enable continuous adjustment of the output speed to torque ratio.A heat-dissipating structure based on a composite phase-change material(PCM)is used.An integral torque control method is used to achieve periodic and controllable explosive power output.Jumping experiments are conducted with typical legged robots to verify the effectiveness of the proposed actuator and control method.Single-legged,quadruped,and humanoid robots jumped to heights of 1.5,0.8,and 0.5 m,respectively.These are the highest values reported to date for legged robots powered by electric actuators.

Correlations between microbial communities in stool and clinical indicators in patients with metabolic syndrome

AIM To analyze the bacterial community structure and distribution of intestinal microflora in people with and without metabolic syndrome and combined these data with clinical indicators to determine relationships between selected bacteria and metabolic diseases. METHODS Faecal samples were collected from 20 patients with metabolic syndrome and 16 controls at Cangnan People's Hospital, Zhejiang Province, China. DNA was extracted and the V3-V4 regions of the 16 S rRNA genes were amplified for high throughput sequencing. Clear reads were clustered at the 97% sequence similarity level. α and β diversity were used to describe the bacterial community structure and distribution in patients. Combined with the clinical indicators, further analysis was performed.RESULTS Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, Fusobacteria were the dominant phyla, and Prevotella, Bacteroides and Faecalibacterium was the top three genera in faecal samples. α diversity analysis showed that the species richness of metabolic syndrome samples(group D) was significantly higher than the control(group C)(P < 0.05), and the microbial diversity of group C was greater than that of group D. According to the principal co-ordinates analysis, the samples of group C clustered more tightly, indicating that the distribution of bacteria in healthy patients was similar. The correlation analysis showed that alkaline phosphatase was negatively correlated with the abundance of Prevotella(P < 0.05). There was a negative correlation between low-density lipoprotein and the abundance of Ruminococcus(P < 0.05) and a positive correlation between the high-density lipoprotein and the abundance of Ruminococcus(P < 0.05). The total protein and the alanine aminotransferase was positively correlated with the abundance of Peptostreptococcus(P < 0.05). CONCLUSION The changes microbial communities can be used as an indicator of metabolic syndrome, and Prevotella may be a target microorganism in patients with metabolic syndrome.

Novel matched filtering method and its application in radar system

The method of using a narrowband filter to realize matched filtering is derived.A novel method of using spectrum sampling to realize matched filtering is presented,and the method can conquer the disadvantages that the narrowband filter cannot adopt the adaptive scheduling of phased array radars and realize matched filtering for several waveforms.A novel error extraction method is proposed,which uses a time division multipath method to realize the intermediate frequency extraction.This method can save lots of space for vehicle-born radar systems,reduce the influence of amplitude and phase distortion caused by devices,and enhance the system reliability.Simulation results show that the spectrum sampling method is applicable,and the implementation of frequency spectrum sampling is elaborated.

电场调制WS_(2)单层分子薄膜光致发光行为

二维材料已经在多个领域得到应用,其中过渡金属硫化物(Transition metal dichalcogenides,TMDCs)因存在带隙而有望用于光电领域.将机械剥离法制备的WS2单层分子薄膜通过干法转移至两种微周期电极结构上,实验发现其光致发光信号受到外加偏压的调制.研究了常温和低温环境下外加偏压对WS2薄膜荧光光谱信号的影响,分析讨论了不同荧光峰强度和峰位的变化行为和物理机理.基于外加偏压,实现对WS2单层分子薄膜光学性能的调制,有望在场效应晶体管、光电探测器、柔性电子器件以及异质结器件等诸多光电领域实现应用.

Prevention of peripherally inserted central catheter-related infections in very low-birthweight infants by using a central line bundle guideline with a standard checklist

Objective:To investigate the effectiveness and feasibility of using a central line bundle(CLB)guideline with a standard checklist in the prevention of peripherally inserted central catheter(PICC)-related infections(CRIs)in very low-birth-weight infants(VLBWIs).Methods:Fifty-seven VLBWIs who underwent PICC insertion at a hospital in Qingdao,China,between November 2012 and June 2013,were monitored with the CLB guideline and a standard checklist.Fifty-three VLBWIs who underwent PICC insertion were monitored by standard hospital procedures.The incidence of CRIs was compared between the two groups.Results:The incidence of infection significantly decreased from 10.0%catheter days in the control group to 2.2%catheter days in the study group(p<0.05).The indwelling catheter time significantly increased in the study group compared to the control group(31.9±15.0days vs.24.8±7.4 days,respectively,p<0.05).Colonization infections also decreased from 6.9% catheter days in the control group to 2.2%catheter days in the study group(p<0.05).The incidence of catheter-related bloodstream infections decreased from 3.1%catheter days in the control group to 0%catheter days in the study group.Conclusion:The use of a CLB guideline with a standard checklist could be an effective and feasible protocol for preventing CRIs and prolonging indwelling catheter timein VLBWIs.

Effects of EGF and IGF-I on in vitro Maturation and Cleavage of Ovine Oocytes

The study investigated the effects of epidermal growth factor（EGF） and insulin-like growth factor 1 （ IGF-I）, alone or together, on the in vitro maturation and cleavage of ovine oocytes, aimed to optimize the in vitro maturation conditions for ovine oocytes. The results showed that the maturation and cleavage rates were 71.2% and 45.5% respectively when the medium was supplemented with 50 ng/mL EGF alone, which was significantly higher than other EGF supplemented groups （0, 10, 20, 30, and 40 ng/mL） （P 〈0.05）. The highest maturation and cleavage rates were 72.9% and 45. 7% when the EGF concentration reached 100 ng/mL. The maturation and cleavage rates were 70. 7% and 58. 5% with 40 ng/mL IGF-I supplemented, which were significantly higher than other treatments （0,10,20,60,80, and 100 ng/mL） （P 〈0.05）. The lowest maturation and cleavage rates were 38.8% and 20.0% when the IGF-I concentration reached 100 ng/mL （ P 〈 0.05 ） When 50 ng/mL EGF and 40 ng/mL IGF-I were used concomitantly,the maturation and cleavage rates were 85. 6% and 61. 0% respectively, which were significantly higher than the treatments with EGF or IGF-I alone （ P 〈 0.05 ）.

Contact etch process optimization for RF process wafer edge yield improvement

Radio-frequency(RF)process products suffer from a wafer edge low yield issue,which is induced by contact opening.A failure mechanism has been proposed that is based on the characteristics of a wafer edge film stack.The large step height at the wafer's edge leads to worse planarization for the sparse poly-pattern region during the inter-layer dielectric(ILD)chemical mechanical polishing(CMP)process.A thicker bottom anti-reflect coating(BARC)layer was introduced for a sparse poly-pattern at the wafer edge region.The contact open issue was solved by increasing the break through(BT)time to get a large enough window.Well profile and resistance uniformity were obtained by contact etch recipe optimization.

Robust Performance of Scene Matching Algorithm

Performance analysis is very important in the study and design of scene matching algorithm. Based on the analysis of the common performance parameters, robustness of scene matching algorithm is defined, including the definitions of robust stability and robust performance, and the corresponding evaluation parameters matching margin and matching adaptability are given. With application of these robustness parameters on 8 scene matching algorithms, quantitative analysis results of algorithm robustness are obtained. The paper provides an important theoretical reference to the performance evaluation of scene matching algorithm.

High Dynamic Bounding and Jumping Motion of Quadruped Robot Based on Stable Optimization Control

Aiming at the environment such as ravines and obstacles that may be encountered in the actual movement,this paper proposes a method for optimizing the bounding and jumping motion based on the ground touching force trajectory and the air motion trajectory of the quadruped robot.The method of optimizing the ground reaction force according to the speed of the demand and the height of the jump,and adjusting the stance and swing time according to the relationship of dynamics and momentum conservation.At the same time,under the constraints of dynamics and energy consumption of the robot system,considering the jumping distance and height,a method for optimizing the air trajectory of bounding and jumping is proposed.State switching and landing stability control are also added.Finally,the experimental results show that the quadruped robot has strong bounding and jumping ability,and has achieved stable bounding movement and forward jump movement of 0.8 m.