Search

Background Hypertension is a major risk factor for cardiovascular disease. Antihypertensive drug therapy should not only consider the characteristics of the patient's blood pressure but also the patient's comorbid conditions. Currently, there is a lack of research on the medication status and influencing factors of hypertensive patients based on family doctor services. Objective To investigate the current medication status of hypertensive patients who purchased family doctor contract services in Jieshou City, Anhui Province, to describe the association between patient medication behavior and patient characteristics, to explore the influencing factors of medication adjustment, and to analyze the rationality of medication use in primary hypertensive patients. Methods Using cluster sampling, from July to August 2021, 48 administrative villages were randomly selected from Jieshou City, Anhui. Data on patient characteristics and medication were collected through face-to-face interviews using a self-made questionnaire. According to the "National Guidelines for the Prevention and Management of Hypertension at the Primary Level (2020 Edition) ", the antihypertensive drugs mentioned by patients in the questionnaire were divided into five categories: category A includes angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), category B includes beta-blockers, category C includes calcium channel blockers (CCBs), category D includes diuretics, and category E includes single-pill combination drugs. Blood pressure data uploaded by patients over the past year were obtained from the backend of iFLYTEK's intelligent voice blood pressure monitor to analyze the medication behavior of patients with different characteristics. Multivariate Logistic regression analysis was used to explore the influencing factors of medication adjustment in hypertensive patients. In this study, "combination medication" refers to taking a combination drug or two or more antihypertensive drugs, and "medication adjustment" refers to patients previously taking other antihypertensive drugs. Results A total of 3, 005 hypertensive patients were included in this study, including 1 291 males (43.0%) and 1 714 females (57.0%), with an average age of (65.5±9.8) years. The medication rate of hypertension was 79.1%, and the rate of combination medication was 40.2%. Among the 2 376 patients taking antihypertensive drugs, the rates of different types of antihypertensive drugs from high to low were (some patients had combination medication) : category E (39.6%), category C (35.1%), category D (20.3%), category A (20.1%), and category B (3.7%) ; the most frequently taken antihypertensive drug was compound lisinopril (33.7%). For patients with an average annual blood pressure ≥160/100 mmHg, 12.2% and 4.9% still did not take antihypertensive drugs. Patients' combination medication mainly involved category E antihypertensive drugs. For patients with an average annual "diastolic pressure≥100 mmHg" and "with complications", the rates of adjusted category A and C antihypertensive drugs increased relatively more; for patients with an average annual "systolic pressure ≥160 mmHg" and "without complications", the rate of adjusted category E antihypertensive drugs increased relatively more. Multivariate Logistic regression results showed that longer duration of medication (OR=1.042, 95%CI=1.031-1.053, P

The development of minimally invasive robotic surgery has always been the focus of the discipline. Pancreaticoduodenectomy has been regarded as the "Mount Everest" of surgical operations because of its high risk and mounting difficulty. Standardized surgical steps and easy-to-follow operation techniques are helpful to promote the application of robotic pancreaticoduodenectomy (RPD). Therefore, in this paper, we summarize the RPD to form an 18-step surgery procedure and analyze the key points of circumferential vessel resection and reconstructive anastomosis techniques, based on the experience of RPD at the First Medical Center of Chinese People's Liberation Army General Hospital, with the hope of promoting the in-depth application of robotics in pancreatic surgery and furthering the establishment of RPD application standards.

Regeneration of adsorption saturated activated carbon by traditional electrochemical technology has the advantages of high regeneration efficiency and no mass loss of activated carbon, but it has defects such as low mineralization efficiency, generation of toxic by-products, and high energy consumption. Electrochemical advanced oxidation(E-AOP) regeneration technology can effectively overcome the problems of traditional electrochemical regeneration. In this paper, the regeneration efficiency and mechanism of activated carbon by traditional electrochemical are briefly described, and the effects of operating parameters (current, electrolyte type and concentration, regeneration location,anode material, etc.) on the desorption-adsorption balance and the mineralization efficiency of pollutants are analyzed. The mechanism and application of three types of E-AOP regeneration technologies(electro-Fenton regeneration, electro-peroxone regeneration, and electro-persulfate regeneration) in the process of activated carbon regeneration are summarized. The electric-Fenton regeneration technology has better regeneration effect, and the problem of metal ion pollution in the system can be effectively overcome by new regeneration. The electro-peroxone regeneration technology does not require the addition of any chemicals and catalysts, which is conducive to the control of reaction conditions and automation of the regeneration process. The electro-persulfate regeneration technology is convenient in operation with low energy consumption and wide applicability. Finally, the problems and development prospects of E-AOP regeneration technology are proposed. This review provides theoretical basis for the development of new efficient and environmentally friendly activated carbon regeneration technologies.

The nano-sized Er2SiO5 powders were prepared by cocurrent coprecipitation method using Er2O3 and tetraethyl orthosilicate (TEOS) as raw materials. The effects of precursor Si/Er molar ratio, calcination temperature, and pH value of reaction system on Er2SiO5 phase composition and microstructure were investigated, and the synthesis mechanism of Er2SiO5 powders was discussed. Results show that pure Er2SiO5 powders with nearly spherical morphology can be obtained from the precursor with Er/Si molar ratio of 20∶12 after being calcined at temperatures at 1300 ℃. Low Er/Si molar ratio can reduce the crystallization temperature of Er2SiO5 and promote the formation of X2-Er2SiO5. The increase of pH value in the reaction system has a certain promotion effect on the formation of ⁅Si—O—Er⁆ structure. During the synthesis process, a ⁅Si—O—Er⁆ network structure is formed in the Er2SiO5 precursor. The ⁅Si—O—Er⁆ network will transform to Er2SiO5 through decomposition and structural reorganization during the calcination process. The Er2O3 impurity is caused by the precipitation of Er3+ of the ⁅Si—O—Er⁆ network structure in the precursor with high Er/Si molar ratio during the crystallization process of Er2SiO5.

Robotic system has overcome the limitations of traditional laparoscopy and promoted the development of minimally invasive surgery. However, in the early stage of robotic hepatopancreatobiliary surgery, the lack of resection and reconstruction technology compatible with the robotic system restricts its application. Based on the previous experience, we propose the circumvascular resection technique, which takes the main blood vessels as the mark, mobilizes the blood vessels and excises the soft tissues around the blood vessels, and the double-low reconstruction technique, which can improve the reconstruction quality by reducing the tissue tension and the tensile stress per unit area during the reconstruction. These two techniques can address the limitations of the robotic system including limit operating space and lack of force feedback, and help to improve surgical safety, reduce learning curve and promote the clinical application of robotic hepatopancreatobiliary surgery.

With expanding globalization and the "cultural turn" in geographic research, the mobile phenomenon of the trans-local production of food culture has received increasing attention from society and academia. Trans-local ethnic theme restaurants are important carriers of food culture, and customer perception has always been a research hotspot for catering enterprises. However, there are few studies on the differences in customer perceptions of the authenticity of trans-local ethnic theme restaurants and the factors affecting them in multi-ethnic countries. To explore the differences in customer perceptions and influencing factors of the originality of food culture in trans-local ethnic minority theme restaurants, this study employed the theoretical framework of the originality of food culture, taking the Enshi Tujia restaurant in Wuhan as the research object, combining online text information and questionnaire surveys, and applying the Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) methods to validate the theoretical framework of the originality of food culture in trans-local ethnic minority theme restaurants. Moerover, it used the Potential Conflict Index (PCI) method to analyze the overall level and internal differences of customers' perceptions regarding originality of trans-local ethnic minority food cultures. Specific factors affecting the differences in customers' perceptions were explored using the one-way nonparametric test and the optimal scale regression analysis. The results of the study are as follows: (1) The customers' perception levels of food and environmental authenticity in the Enshi Tujia restaurant in Wuhan were 0.60, but the customers' perception level of service authenticity was -0.06. The PCI values of food and environmental authenticity were 0.09 and 0.08, respectively, but the PCI values of service authenticity was 0.35. (2) Significant factors contributing to the differences in customers' perceptions of the originality of the dietary culture, such as expectations and information access, were: the overall level and internal differences in customer perceptions of food culture were not significant. Significant factors of customer perception differences, with importance indexes of 0.566 and 0.270, respectively, were found. Education was a significant factor leading to customer perception differences in food and service authenticity, with importance indexes of 0.081 and 0.141, respectively. Stimuli such as the degree of understanding of Enshi and the experience of traveling there lead to significant differences in the perception of food authenticity, with importance indexes of 0.144 and 0136. Recent dining time and income indicated that customers' perception of environmental authenticity and service authenticity differ significantly, with importance indices of 0.178 and 0.256, respectively, whereas cultural background factors such as the place of origin did not have a significant impact on the difference in customers' perceptions of the food culture authenticity. The study conclusions as follows: (1) Customers' perception of food authenticity and environmental authenticity of ethnic minority themed restaurants was high with small internal differences, while the perception of service authenticity was low with large internal differences. (2) Expectations and information acquisition channels are important factors leading to significant differences in customers' perceptions, but the influence of cultural background factors such as place of origin, degree of understanding of Enshi, and experience of traveling there is relatively limited. (3) Trans-local ethnic minority theme restaurants are micro spaces for the exchange and fusion of food culture in the source place and food culture there, which can satisfy the diversified dietary consumption needs of different customers, such as local and foreign ethnic minority customers. Trans-local production of ethnic minority theme restaurants is conducive to promoting the formation and development of a unified multi-ethnic state in China. This study expands the scale of research on the originality of food culture, enriches the theoretical content of the perception of the originality of food culture, and provides case references and a theoretical basis for the trans-local production and operation of ethnic minority themed restaurants.

Controllable variable stiffness compliant actuator mechanism has the characteristics of high compliance, high environmental adaptability and good man-machine interaction. The variable stiffness compliant actuator mechanism is based on the transmission principle of a four-bar linkage with a zero-length rack. The variable stiffness control can be realized by changing the properties and the winding mode of the elastomer, or the configuration scheme. Through configuration analysis and structure design, the stiffness and torque models of the compliant actuator mechanism are established to reveal its stiffness behavior. The Lagrangian method is used to establish the dynamic model of the compliant actuator mechanism, and the frequency theoretical results are obtained by solving the average stiffness. The virtual prototype is established to motion simulation, which reveals its performance characteristics and verifies the correctness of theoretical analysis. Compared with other similar designs, the compliant actuator mechanism proposed has the characteristics of miniaturization and lightweight with strong applicability. It can be used as a single module and integrated into the exoskeleton system.

Background Early treatment is crucial to the delay of the progression of type 2 diabetes mellitus with stable angina pectoris (T2DM-SAP) , which has poor prognosis, such as high rates of disability and mortality. As traditional Chinese medicine (TCM) has unique advantages in preventing diseases, developing a model with TCM and western medicine factors associated with major adverse cardiovascular and cerebrovascular events (MACCEs) incorporated may be a reliable tool that could be used to predict the risk of MACCEs in patients with T2DM-SAP. Objective To develop and assess the applicability of a risk prediction model for MACCEs in T2DM-SAP patients using identified risk factors associated with MACCEs in this group. Methods Participants were 674 inpatients with T2DM-SAP who received diagnostic and treatment services from The First Affiliated Hospital of Henan University of CM from 2012 to 2019. Through the hospital information system, electronic medical records and follow-up data of these patients were collected, including demographics, clinical characteristics, laboratory parameters, TCM symptoms and syndrome differentiation, and outcome (prevalence of MACCEs) . Patients were classified into a MACCEs group (n=190) and a non-MACCEs group (n=484) by prevalence of MACCEs. Independent risk factors for MACCEs in T2DM with SAP were identified using univariate and multivariate Logistic regression, and used to develop a nomogram-based predictive model. Then the model was internally validated using the bootstrap approach, and its predictive value was estimated using ROC analysis, C-index, calibration plot, Hosmer-Lemeshow test and decision curve analysis. Results Based on the multivariate Logistic regression analysis, the factors associated with MACCEs in T2DM-SAP patients (P30%, indicating that the model may be clinically beneficial. Conclusion The risk predictive model for MACCEs in T2DM-SAP patients was developed using the associated factors (including age, cerebrovascular disease history, serum creatinine, dark purple tongue, decreased tongue coating, thready pulse, and obstruction of collateral channels caused by wind-phlegm) identified by us, which has been proven to have good discrimination, calibration, and clinical effectiveness, and could be used as a tool for assessing the risk of MACCEs in patients with T2DM-SAP.

Nano-sized Dy2O3 doped ZrO2 powders (DySZ) were synthesized by cocurrent co-precipitation method. The effects of Dy2O3 content, cation concentration, pH value and calcination temperature on the phase composition, crystal structure, grain size and micromorphology of DySZ powders were investigated. Results show that under different synthesis conditions, the spherical DySZ powders have nano scale characteristics with a size range of 10-30 nm, Dy2O3-doping can promote the DySZ stabilized as tetragonal structure. The doping amount of stabilizer has a significant effect on the phase composition of DySZ powder. Single tetragonal DySZ can be obtained with 10%(mass fraction) Dy2O3-doping. No significant effect can be found between the tetragonality, microstructure of DySZ powders and the stabilizer content, cation concentration, pH value as well as calcination temperature. The average grain size exhibits a slight decrease with the increase of stabilizer content, cation concentration and pH value. Meanwhile, the elevated calcination temperature can promote the crystal growth of DySZ.

Objective To compare the effects and characteristics of cigarette smoke exposure (CSE) alone and CSE combined with airway instillation of bacterial lipopolysaccharide (LPS) in chronic obstructive pulmonary disease (COPD).Methods Male SD rats were randomly divided into control, CSE, and CSE+LPS groups, with 10 rats in each group. After 24 weeks, the models were established and the lung function of the rats was measured. Hematoxylin-eosin (HE) staining was performed to observe the pathological changes in the airway and lung tissue. The ELISA method was used to detect the level of serum interleukin-8 (IL-8) and tumor necrosis factor α (TNF-α) in peripheral blood.Results Airway resistance (RI), functional residual capacity (FRC), and chord compliance (Cchord) of the CSE and LPS+CSE groups were higher than those of the control group (all P < 0.05), while the tidal volume (TV), minute volume (MV), and forced expiratory volume in 50 ms (FEV50) / forced vital capacity (FVC) of the CSE and LPS+CSE groups were lower than those of the control group (all P < 0.05). HE staining of lung tissue showed that the average alveolar intercept and thickness of the small airway walls were higher in the CSE and LPS+CSE groups than those in the control group. Compensatory enlargement was evident in the alveolar cavity of the CSE and CSE+LPS groups, and the alveolar septum widened, with a fusion of pulmonary alveoli in the CSE+LPS group. The levels of IL-8 and TNF-α in serum of the CSE and CSE+LPS groups were higher than those of the control group (all P < 0.05). The level of TNF-α in serum of the CSE+LPS group was higher than that of the CSE group (P < 0.05).Conclusion The CSE combined with LPS method is superior to CSE alone for establishing the COPD rat model, and the combined model is closer to clinical manifestations.

BACKGROUND There are large amounts of copper-lead-zinc polymetallic sulfide ore resources in Yunnan Province, China, but the efficient separation of these resources remains a major problem. OBJECTIVES To improve the separation efficiency of valuable minerals in mixed concentrates. METHODS In this study, the major elemental content, phase composition, mineral composition, particle size characteristics, and monomer liberation degree of a mixed concentrate were analyzed using a variety of modern detection methods such as chemical analysis, X-ray diffraction, and mineral liberation analysis (MLA). RESULTS The results showed that the mixed concentrate had fine particles, and some minerals occurred as intergrowths or inclusions. The monomer liberation degree of the target minerals chalcopyrite, galena, and sphalerite was medium to low, ranging from 69.28% to 70.56%. It was preliminarily predicted that the theoretical separation efficiencies of copper, lead, and zinc in the mixed concentrate were 71.63%, 62.97% and 72.72%, respectively. CONCLUSIONS Improving the grinding fineness of mixed concentrates to promote the full liberation of metal minerals is a key way to improve the separation efficiency of copper, lead, and zinc minerals.

In this paper, nano-sized Gd2SiO5 powder was synthesized by a cocurrent chemical co-precipitation method with Gd2O3 and TEOS as raw materials. The thermal behavior of precursor, phase composition and microstructure of the obtained powder were investigated, the synthesis mechanism was also discussed. The results show that lower Gd：Si molar ratio in precursor and higher pH value in reaction system can lead to the formation of Gd9.33(SiO4)6O2 phase. On the contrary, Gd2O3 impurity is formed in the obtained Gd2SiO5 powder. In this study, the relatively pure Gd2SiO5 powder can be synthesized at 1000-1300 ℃ with Gd/Si molar ratio as 20：11 and pH value in the range of 9-10. The obtained powder inhibits irregular morphology with average grain size of 100-200 nm. During the synthesis process, the precursor is generated in the form of —[Si—O—Gd]— network, and then translated to Gd2SiO5 grains, as well as Gd9.33(SiO4)6O2 and Gd2O3 impurities.

Insoluble dietary fibers (IDFs) were extracted from sweet potato leaves and modified by physical crushing or using an acid, alkali-hydrogen peroxide, and cellulases. The modified samples were characterized, and changes in their physical and chemical properties were evaluated. The effects of different modification treatments on the micromorphology, chemical structure, crystal phase structure, and functional properties were investigated. Scanning electron microscopy showed that the microstructure of IDF in sweet potato leaves was altered by the different treatments. Fourier transform infrared spectroscopy suggested no obvious changes in the chemical structure. Additionally, the specific surface areas of IDFs in sweet potato leaves before and after modification varied. X-ray diffraction analysis indicated that the positions of characteristic diffraction peaks were mostly unchanged before and after modification. The cation exchange capacity and total negative charge of IDFs increased by 0.31~2.86- and 0.75~2.88-fold, respectively. Acid-modified SIDF3 showed the highest water-holding, swelling, and glucose adsorption capacities, which were 0.34, 4.33, and 0.16~0.39-fold higher than those of unmodified SIDF1, respectively. The oil-holding capacity of enzyme-modified SIDF5 was the highest, 0.24-fold higher than that of unmodified SIDF1. The results demonstrated that the properties and functional properties of sweet potato leaves can be altered by different modification treatments, providing a basis for further application of insoluble dietary fibers in sweet potato leaves. [ABSTRACT FROM AUTHOR]

The adaptive p-version finite element method is combined with bi-directional evolutionary structural optimization（ BESO） for the influence of calculation accuracy on the optimization result in the topology optimization process. According to the error control parameter setting,the element order is improved adaptively through the element energy error analysis,which effectively improves the finite element calculation accuracy,and the sensitivity filtering algorithm and the stabilization strategy are adopted to mitigate the checkerboard and iterative oscillation phenomenon. The feasibility of the method is verified by the example calculation of the minimum compliance topology optimization problem,the results show that the proposed method can improve the accuracy of topology optimization under rougher meshes,and obtain higher optimization efficiency and better optimization results.

The purpose of the study was to improve the cell wall-breaking rate of industrial Saccharomyces cerevisiae and its application value. The effects of heat, alkali and ultrasonic synergistic treatment on the cell wall-breaking rate of industrial Saccharomyces cerevisiae ScY01 strain were explored. The results showed that the wall-breaking rate of ScY01 strain with a concentration of 6 g/L was 91.78% when treated with heat (boiling water bath 12.5 min), alkali (sodium hydroxide 0.6 g) and ultrasonic crushing (ultrasonic power 450 W, radiation time 11 s, radiation interval 15 s, ultrasonic time 20 min). The amount of protein released after cell fragmentation was used for preliminary application characterization, the total protein release by synergistic treatment was 11.54 times higher than that of alkali alone, 10.26 times higher than that by boiling alone, and 4.01 times higher than that by ultrasonic alone. The study indicates that the synergistic treatment is suitable for model Saccharomyces cerevisiae strain CEN.PK2-1c, and the experimental results can provide a new method for efficient crushing of industrial Saccharomyces cerevisiae cells. [ABSTRACT FROM AUTHOR]

To explore the effect of organic and inorganic nitrogen on yield and quality of high erucic acid rape-seed, we studied the effects of 6 different treatments (pure organic fertilizer, pure inorganic fertilizer, 20%, 30%, 40%, and 50% organic fertilizer substitution) on yield, quality, soil nutrients, and economic benefits of high erucic acid industrial rapeseed (cv Mianyou 309). The results showed that compared with pure chemical fertilizer, a certain proportion of organic and inorganic nitrogen could significantly increase rapeseed yield. The yield of 30% organic nitrogen treatment was the highest, reaching 3501.63 kg/hm2, which was 24.84% higher than that of pure organic fertilizer and 23.47% higher than that of pure inorganic fertilizer. Combination of organic and inorganic nitrogen promoted the growth and development of the main stem and branches of rapeseed. Under this treatment, the erucic acid content was not affected but the oil content was also increased, so as to significantly increase the erucic acid and edible oil yield per unit area. It also increased the soil nitrogen storage, so that the soil might maintain a higher fertility level for higher economic and environmental benefits. [ABSTRACT FROM AUTHOR]

BACKGROUND In the Western Yunnan, there is an abundance of low-grade gold resources with uneven grain size, complicated ore structure and incomplete separation. Using the traditional mineralogical analysis process, it is difficult to achieve accurate and rapid determination of the occurrence of gold and the inlay characteristics of gold-bearing minerals. OBJECTIVES To study the mineralogy process of polymetallic gold ores in Western Yunnan. METHODS:The mineral composition, dissemination size, and inclusions characteristics of gold ores were analyzed, and the effect of mineralogical properties of gold-bearing minerals on the recovery of gold was determined. The X-ray Fluorescence Spectrometer and eight-lamp flame graphite furnace integrated Atomic Absorption Spectrometer were used for the analysis of ore properties, and the ore samples were analyzed by Mineral Liberation Analysis. RESULTS The results show that gold is mainly in the form of free gold, with superfine dissemination size of gold minerals, mainly concentrated on the 0.01 mm to 0.02 mm granularity level. Gold smaller than 0.074 mm presents as free monomer natural gold, which accounts for 50.08% of the total gold. Other gold occurs as inclusions in pyrite, magnetite and chalcopyrite. However, the gold-bearing minerals have small grain size, poor dissociation, and uneven embedding. CONCLUSIONS Increasing the dissociation degree of major gold-bearing minerals is an important method for increasing gold recovery.

Objective To compare the effect of endostar via micro pump or intraperitoneal injection combined with epirubicin on breast cancer in mice. Methods We established the BALB/c mice breast cancer model by orthotopically inoculating 4T1 cells, then they were randomly divided into six groups: blank group(0.9%NaCl, ip), standard control group(EPI, ip) and four experimental groups:(1) rhES(ip)+EPI(ip); (2) rhES(pump)+EPI(ip); (3) rhES(ip); (4) rhES(pump). We monitored tumor xenografts volume, mice weight and drug adverse events every two days until the termination of treatment; We also detected their bioluminescence activity on day 10; after the treatment, mices were sacrificed, tumor xenografts were completely removed and we detected platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) expression level in tumor tissues by IHC. Results The effect of endostar via micro pump(7 mg/(kg.d)) was better than intraperitoneal injection on breast cancer in mice(P=0.01). The effect of endostar via micro pump combined with epirubicin was equivalent with intraperitoneal injection of two drugs(P > 0.05), and the adverse events in former groups were reduced. Conclusion The effect of endostar via micro pump combined with epirubicin is equivalent with intraperitoneal injection of two drugs, which provides an experimental basis for the possibility of breast cancer patients carrying endostar micro pump at home, however, more clinical evidence are needed.

The interface plays a key role on the mechanical properties of Cf/SiC composite prepared by GSI process. The ideal interface should not only prevent carbon fiber from being etched by Si vapor, but also adjust the bonding force between C fiber and SiC matrix. SiC coating prepared by CVD was chosen as the interface and its effect on the mechanical properties and fracture features of GSI Cf/SiC composite was discussed, and the influencing mechanism was analyzed. The results show that GSI Cf/SiC composite without CVD-SiC interface has poor mechanical properties, exhibiting brittle fracture feature. The bending strength, elastic module and fracture toughness are 87.6MPa, 56.9GPa and 2.1MPa·m1/2, respectively. The mechanical properties of GSI Cf/SiC increase with the increase of the thickness of CVD-SiC coating at first, then decrease with the continuous increase of the thickness of CVD-SiC coating. The Cf/SiC composite with 1.1μm thickness of CVD-SiC coating has the best mechanical properties, and the bending strength, elastic module and fracture toughness are 231.7MPa, 87.3GPa and 7.3MPa·m1/2, respectively. The action mechanism of CVD-SiC interface coating on the composite is mainly on the three aspects:load transfer, preventing C fiber from being etched by Si and adjusting fiber/matrix bonding status.

C/C-SiC composites were prepared by the combined process of chemical vapor infiltration (CVI) and gaseous silicon infiltration (GSI) using C/C green body with the density of 1.0g/cm3. Effect of CVI C/C-SiC intermediate composites' density on the phase composition, microstructure and mechanical properties of CVI-GSI C/C-SiC composites was studied. The results show that as the CVI C/C-SiC intermediate composites' density increases, the residual C content increases and residual Si content decreases in the CVI-GSI C/C-SiC composites, the SiC content increases first and then decreases, and the density of CVI-GSI C/C-SiC composites increases first and then decreases; as the CVI C/C-SiC in termediate composites' density is increased from 1.27g/cm3 to 1.63g/cm3, the mechanical properties of CVI-GSI C/C-SiC composites increase at first, which then decrease with the further increasing of CVI-C/C-SiC composites' density. Specifically, when the CVI C/C-SiC composites density is 1.42g/cm3, the prepared CVI-GSI C/C-SiC composites has the best mechanical properties, with flexure strength, flexure modulus and fracture toughness of 247.50MPa, 25.63GPa and 10.08MPa·m1/2, respectively.

BackgroundWhen the activation method is used to measure the irradiated thermal neutron fluence of single-crystal silicon neutron transmutation doping, the measured value may have a certain deviation due to the difference in the curve shapes of the target reaction cross-section as a function of neutron energy between activated detector and silicon.PurposeThis study aims to suppress the measurement influence caused by reaction cross-section difference between activation detector and silicon, and to reduce the measurement deviation.MethodsBased on the Stoughton-Halperin convention relation, the binary first-order equations solution method and a linear least-squares fitting method were established. A variety of activation detectors and their combinations were applied to experimental measurement to verify their feasibility. These activation detectors were placed in the irradiation facility and irradiated in the Minjiang test reactor at Sichuan province. Finally, all of detectors were taken out from the reactor, and the radioactive activity was measured by high purity germanium γ spectrometer.ResultsThe results show that obvious differences exist in the measurement values of different activated detectors at the same position, and the measurement deviation based on suitable detector combination is greatly reduced to be less than 3% by using above two methods.ConclusionsThe two methods proposed in this study can effectively suppress the influence of the reaction cross-section difference on measurement. The equation method has certain advantages over the least-square method with only two kinds of compulsory detectors, it can also be applied to other thermal neutron irradiation samples.

This study established a two-dimensional mathematical model of solidification and heat transfer for a bloom with a 310 mm×360 mm cross-section using ANSYS software, which was verified by nail-shooting experiments in the narrow side of the bloom and surface temperature testing. The effect of the casting process parameters, such as superheat, casting speed, and secondary cooling intensity, on the solid fraction in the strand centerline and the solidified shell was investigated. Moreover, the optimum casting speed and the optimum solid fraction in the core of the partially solidified strand throughthe soft reduction zone were determined by the model considering the hot ductility of the high-carbon wear-resistant ball steel BU. Plant trials of BU with different casting speeds were performed to validate the theoretical model and analyze the effect of the casting speed on the segregation and shrinkage cavity of BU on a 310 mm×360 mm bloom caster equipped with final electromagnetic stirring (F-EMS) combined with mechanical soft reduction (reduction amount with 17 mm). The results show that the inner defects (e. g., center segregation, V-segregation, and shrinkage cavity) significantly improve when the casting speed is adjusted to meet the required soft reduction zone as a matter of priority; otherwise, the casting speed is only adjusted to preferentially satisfy the required F-EMS stirring region. The inner quality does not show any obvious improvement. Except for the internal cracks and the negative center segregation caused by the improper distribution of the reduction amount, the inner defects (e. g., macro segregation and shrinkage cavity) significantly improve with a casting speed of 0.52 m·min-1 and a solid fraction in the strand centerline ranging from 0.30 and 0.75 in the soft reduction zone.

The 3-D needled C/C preforms with different densities deposited by chemical vapor infiltration (CVI) method were used to fabricate C/C-SiC composites by gaseous silicon infiltration (GSI). The porosity and CVI C thickness of the preforms were studied, and the effects of preform density on the mechanical and thermal properties of C/C-SiC composites were analyzed. The results show that with the increase of preform density, the preform porosity decreases and the CVI C thickness increases from several hundred nanometers to several microns. For the C/C-SiC composites, as the preform density increases, the residual C content increases while the density and residual Si content decreases. The SiC content first keeps at a high level of about 40% (volume fraction), which then quickly reduces. Meanwhile, the mechanical properties increase to the highest values when the preform density is 1.085g/cm3, with the flexure strength up to 308.31MP and fracture toughness up to 11.36MPa·m1/2, which then decrease as the preform density further increases. The thermal conductivity and CTE of the composites, however, decrease with the increase of preform density. It is found that when the preform porosity is too high, sufficient infiltration channels lead to more residual Si, and thinner CVI C thickness results in the severe corrosion of the reinforcing fibers by Si and lower mechanical properties. When the preform porosity is relatively low, the contents of Si and SiC quickly reduce since the infiltration channels are rapidly blocked, resulting in the formation of large closed pores and not high mechanical properties.

Aiming at the problems of multi-scale, multi angle and occlusion in mask wearing detection in complex scenes, a mask wearing detection algorithm in complex scenes based on improved FCOS is proposed in this paper. Firstly, in order to improve the feature extraction ability of the network for masks with different scales, the packet residual connection structure of Res2Net is introduced into the backbone network of the algorithm, and the deformable convolution is integrated to expand its modeling ability for objects with unknown shapes. Then, a feature pyramid integrating attention mechanism is designed to give different weights to feature channels and suppress useless feature information. Finally, according to the relevant statistical characteristics of the target mask, the positive and negative samples are automatically divided to improve the sample quality of masks with different scales, and Generalized Focal Loss is introduced to jointly train the classification score and positioning quality score of samples so as to improve the performance of the algorithm. The experimental results show that the mAP of improved algorithm in this paper improves 6.7 percentage points compared with the original FCOS in the detection of mask wearing in complex scenes. Meanwhile, compared with some mainstream target detection algorithms, the improved algorithm in this paper also has better effect and robustness. [ABSTRACT FROM AUTHOR]

In order to obtain up-conversion luminescent materials with bright red emission, a series of Yb3+, Er3+, Mn2+- doped Gd2O3 microcrystals were prepared by simple chemical precipitation method, and their morphology, structure and luminescent properties were characterized. The results show that Gd2O3 :10%Yb3+, 1% Er3+ microcrystals exhibit a flower-like morphology, and the average diameter is 2. 28 μm. After calcination at high temperature, the sample presents a cubic Gd2O3 structure with good crystallinity, and Mn2+ doping does not affect the morphology and crystal phase of the product. Under 980 nm near-infrared light excitation, Gd2O3 : 10% Yb3+, 1% Er3+ microcrystals show orange-red luminescence, which corresponds to the 4F9/2→4I15/2 transition of Er3+. With the increase of Mn2+ doping concentration (molar fraction), the luminescence intensity of Gd2O3:10% Yb3+, 1% Er3+, x% Mn2+ microcrystals first increases and then decreases, and the luminescence color gradually turns to red, which is consistent with the CIE color coordinate. At the same time, the up-conversion luminescence mechanism and the possible energy transfer process of Gd2O3: 10% Yb3+, 1% Er3+, x% Mn2+ microcrystals were analyzed according to the relationship between luminescence intensity and excitation power. [ABSTRACT FROM AUTHOR]

In view of problem of difficult location of fault existed in real time fault detection methods of powerful conveyor belt, the paper proposed an identification algorithm of joints of powerful conveyor belt based on image processing technology which takes a joint as a reference point. Firstly, based on the characteristics of joint points, a joint point is represented by a value. According to the value, upper or lower joint point could be distinguished simply. Then according to the features of joints, matching style of the longest common subsequence algorithm was modified and applied to recognize joint. The practical application showed that the algorithm has high precision and fast speed, can efficiently recognize joints of powerful conveyor belt and satisfy demand of joint locating of fault detection of powerful conveyor belt.

A new general analytical synthesis method for arbitrary current mode filter was presented.The method was based on the analytical decomposition of a complicated high-order transfer function into n lossless integrators and n cur-rent proportional blocks by a succession of innovative algebra process.The filter structure based on MCCIIs was pro-posed with the following advantages: 1) it can be used not only for arbitrary-order filters,but also for different filter types such as Butterworth,Chebyshev and Elliptic;2) the circuit structure proposed only contains（2n+1） active elements,（2n+1） resistors and n capacitors;3) all the elements are grounded,so it is convenient to be integrated;4) the different filter functions such as high-pass,low-pass,band-pass,band-reject and all-pass can be obtained when it act as a Butter-worth filter.A third-order elliptic low-pass filter and a sixth-order Butterworth universal filter were employed to demon-strate the realization scheme.The validity of the proposed structure was verified through PSPICE simulations.

The enzymatic hydrolysate of mussel was used as the raw material for preparing the thermal reaction essence with a seafood flavor through the Maillard reaction. The effects of reducing sugar type and addition amount, reaction time and reaction temperature on the Maillard reaction were investigated through using sensory scores as the indicators. The conditions for preparing mussel thermal reaction essence were optimized by the orthogonal experiments: mussel enzymatic hydrolysate 10%, xylose 5%, reaction time 90 min, reaction temperature 100 °. The obtained mussel essence had a high intensity of natural seafood flavor. The comparison of the powder state and physico-chemical properties of the essence powder prepared by ultrasonic spray-freeze drying, vacuum freeze-drying and spray drying revealed that the essence powder prepared by ultrasonic spray-freeze drying was the best, having a light yellow color, fine size, evenly dispersed nature, and high solubility. The solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analyses revealed a total of 28 volatile compounds in the essence prepared via the three drying processes, including aldehydes, alcohols, pyrazines, furans, esters and ketones. The volatile components of the essence powders prepared by the three drying processes differed significantly, with the volatile profile of the essence obtained by the ultrasonic spray-freeze drying being the closest to that prior to drying (i.e. best powder state and strongest flavor). This study provides a theoretical basis for the production and processing of high-fidelitymussel thermal reaction essence with seafood flavor. [ABSTRACT FROM AUTHOR]

In this study, a single on polymer electrolyte of PEGMEM-co-AMPS-Li was developed van free radical polymerization reaction, using 2-Acrylamido-2-melhyTTpropaneslllfonic add (AMPS) and poly (ethylene glycol) methyl ether methacrylate (PEGMEM) as polymeric monomers. Li+ was grafted onto copolymer matrix by lithium reaction of lithium hydroxide solution. PEGMEM provides migration path for lithium-ion. Grafting segments of AMPS could effectively inhibit the crystallization of ethylene oxide (EO) chain segments in PEG-MEM, and introduce Li+ onto copolymer matrix to form single-ion electrolyte. The electrolyte exhibits good lithium-ion migration number and electrochemical window, and good interface compatibility with positive and negative electrodes, demonstrating the potential application value of high-performance single-ion polymer electrolyte in improving the safety and rate cycle stability of lithium-ion battery. [ABSTRACT FROM AUTHOR]

The heating furnace of residue hydrogenation unit has the problems, such as high excess oxygen content, large fluctuation of oxygen content in radiation chamber, high concentration of NO% in exhaust gas, high exhaust gas temperature and low thermal efficiency. To solve the above problems, a comprehensive transformation of the hating furnace system is carried out. Adding an advanced process controller, the fluctuation of negative pressure and oxygen content of the heating furnace are significantly reduced, making the operation of the heating furnace more stable. Replacing the low nitrogen burner, the mass concentration of NOx in the discharged flue gas is reduced from 80.43 mg/m³ to 24.66 mg/m³, which is far lower than the national emission standard (100 mg/m³). Upgrading the heat pipe air preheater to a steel pate and cast iron plate combined air preheater, the flue gas temperature in summer is reduced from more than 130 °C to about 115 °C, and the thermal efficiency of the heating furnace increases significantly. After a series of transformation, the operation indexes of the heating furnace of the residue hydrogenation unit have been greatly improved, and the transformation purpose of energy conservation and environmental protection has been achieved. [ABSTRACT FROM AUTHOR]

ZnO@rGO hybrid filer Is fabricated by liquid phase method with graphene oxide (GO) as the career and zinc acetate as zinc source. The structure and morphology of the hybrid filler are characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectrometer (Raman) and scanning electron microscopy (SEM). A series of epoxy resins (ZnO@rGO/EP) thermally conducive insulating composites are prepared by adding ZnO@rGO hybrid filler. The influence of filler content on the properties of the thermally conducive insulating composites is studied. The results show that the hybrid filler could be dispersed evenly in epoxy resin. With the increasing of filler content, the thermal conductivity of ZnO@rGO(O2)/EP composites increases continuously, and the impact strength first increases and then decreases. When 22.04 vol. % ZnO@rGO(O2) is added, the thermal conductivity of the composite material reaches 0.58 W/(m • K), which is 205.3% higher than that of pure epoxy resin, and the impact strength increases from 15.9 kJ/m² for the pure epoxy resin to 25. 0 kJ/m². Meanwhile, the composite material still maintains good insulation properties. [ABSTRACT FROM AUTHOR]

Due to the limitation of antenna array rotation and electron beam offset for the rotating phased array radar, the target being tracked can not be illuminated by the line period of about 66. 7% per day. The adaptive variable updata rate tracking algorithm which can be continuously selected is not suitable for rotating phased array radar. On the basis of Cohen's research, a discrete variable updata rate tracking algorithm for rotating phased array radar target tracking is proposed. The algorithm estimates the motion state in rectangular coordinate system, calculates the tracking residual in spherical coordinate system, normalizes the residual error by measuring noise, and determines the sampling period of the next cycle according to the relative position between the antenna normal direction and the target at the current sampling time, so as to avoid the problem of complex calculation of process noise. Finally, a circular maneuvering target is taken as an example to verify the correctness and effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metal Materials & Engineering is the property of Northwest Institute for Nonferrous Metal Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Application of three-dimensional printing technology provides an effective supplementary means for minimally invasive and individualized surgery of posterior column fracture of tibial plateau. OBJECTIVE: To summarize the present situation of diagnosis and treatment of posterior column fracture of tibial plateau, and to look forward to the effect of three-dimensional printing technology in the diagnosis and treatment of posterior column fracture of tibial plateau. METHODS: A computer-based retrieval of CNKI, WanFang, and PubMed databases was conducted using the keywords of 'the fracture of tibial plateau, posterior column, 3D printing technology" in Chinese and English, respectively. Totally 210 articles were retrieved, and 56 eligible articles were finally included for review based on inclusion and exclusion criteria. The detailed contents included classification of posterior column fracture of tibial plateau, surgical treatment, application status of three-dimensional printing technology and postoperative rehabilitation. RESULTS AND CONCLUSION: Posterior column fracture of tibial plateau is a special type of plateau fracture, so the traditional method may lead to misdiagnosis. However, the solid model based on three-dimensional printing can directly make diagnosis, and analyze the injury mechanism and classification. In the treatment of posterior column fracture of tibial plateau, there are various traditional surgical approaches to choose: the posterior approach (postmedial approach, posterolateral approach), backward medial inverted 'L' into the approach, anterolateral/anterolateral approach, anterolateral posterolateral combined approach, arthroscopy minimally invasive treatment and so on, but have not been unified yet. The application of three-dimensional printing technology has further improved the diagnosis and classification of posterior column fracture of tibial plateau, and provides a reference for preoperative guidance of personalized surgical plan, surgical approach selection, estimation of intraoperative bone implant volume and postoperative rehabilitation. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of quality control circle(QCC)in reducing the risk of needle-stick injury during the infusion among pediatric nurses. Methods: A QCC group was set up to analyze potential reasons of needle-stick injury during the infusion among pediatric nurses. The theme of QCC activities was established and improvement measures were carried out. The incidence rates of needle-stick injury before implementation of QCC activities(January 2016 to July 2016)and after implementation of QCC activities(September 2016 to March 2017)were compared. Results: There were 115 times of needle-stick injury reported before implementation of QCC activities, with 16.43 per 25 person-times monthly. There were 41 times of needle-stick injury reported before implementation of QCC activities, with 5.86 per 25 person-times monthly. The incidence of needle-stick injury dropped significantly from 65.72% to 23.44%, and the target achievement ratio was 102.67%. Conclusion: The QCC is effective to reduce the risk of needle-stick injury during the infusion and improve the overall quality of pediatric nurses. [ABSTRACT FROM AUTHOR]

With the continuous development and consumption of lead sulphide resources, the efficient development and utilization of oxidized lead ore has become an important way to ensure the demand for lead in China. This paper is aimed treating the oxidized lead ore with Pb grade of 4. 54% in the Tengchong area of Yunnan, which contains mainly anglesite cerusite and a small amount of galena. The ore was deep vulcanized by vulcanization-xanthate method and then flotated with mixed collector. In the process, the effects of grinding fineness, dosage and dosage on the enrichment of lead minerals were studied. When the ore grinding fineness is 80%-74 µm, the flotation closed-circuit test can obtain lead concentrate products with higher grade and recovery rate. The lead concentrate contains Pb 64.50%, Pb recovery rate is 90.74%, and the sorting index is good. This study can provide a certain technical basis for the development and utilization of similar ore resources. [ABSTRACT FROM AUTHOR]

In order to settle the problems related to low management efficiency and difficult coordination in the later operation and maintenance stage of urban underground integrated pipe gallery at present. The application of "BIM +" technologies in urban underground pipe gallery operational phase is analyzed. A visual operation and maintenance management platform based on BIM technology is established. This study finds that rich information stored in the BIM model can provide strong information support for operation maintenance decision and implementation. Meanwhile, BIM technologies can generate more benefits, such as reducing risks related to operation and maintenance. It reflects the application value and feasibility of BIM technologies at the operation and maintenance management stage. [ABSTRACT FROM AUTHOR]

o improving the penetration capability of EFP, the influence rule of structural parameters of built-in sensitive devices on EFP molding was studied by using AUTUDYN numerical calculation software, and the reliability of the calculation model was tested by the typical terminal sensitive projectile EFP warhead penetration target test. The results show that when the height of the sensitive device increases from 0.15 times the charge height to 0.50 times, the formed EFP speed increases by 1.29%, the aspect ratio decreases by 30.9%, and when the diameter of the sensor increases from 0.3 times the diameter of the charge to 0.8 times the diameter of the charge, the formed EFP speed reduces by 5.14%, and the aspect ratio decreases by 17.5%. When the distance from the starting point of the sensitive device increases from 0.1 times the charge height to 0.55 times, the speed and aspect ratio of the EFP after molding decreases first and then increases, and the low value appears at 0.35 time the charge height. For the stepped sensitive device, when the diameter ratio of the sensitive device increases from 0.4 to 1.0, the EFP speed decreases by 3.2%, and the aspect ratio increases by 39.1%. When the height ratio of sensor increases from 0.4 to 1.0, the EFP speed reduces by 4.2% and the aspect ratio increases by 38.4%. [ABSTRACT FROM AUTHOR]

Vegetation phenology is a comprehensive indictor for the responses of terrestrial ecosystem to climatic and environmental changes. Remote sensing spectrum has been widely used in the extraction of vegetation phenology information. However, there are many differences between phenology extracted by remote sensing and site observations, with their physical meaning remaining unclear. We selected one tile of MODIS data in northeastern China (2000-2014) to examine the SOS and EOS differences derived from the normalized difference vegetation index (NDVI) and the simple ratio vegetation index (SR) based on both the red and near-infrared bands. The results showed that there were significant differences between NDVI phenology and SR-phenology. SOS derived from NDVI averaged 18.9 days earlier than that from SR. EOS derived from NDVI averaged 19.0 days later than from SR. NDVI-phenology had a longer growing season. There were significant differences in the inter-annual variation of phenology from NDVI and SR. More than 20% of the pixel SOS and EOS derived from NDVI and SR showed the opposite temporal trend. These results caused by the seasonal curve characteristics and noise resistance differences of NDVI and SR. The observed data source of NDVI and SR were completely consistent, only the mathematical expressions were different, but phenology results were significantly different. Our results indicated that vegetation phenology monitoring by remote sensing is highly dependent on the mathematical expression of vegetation index. How to establish a reliable method for extracting vegetation phenology by remote sensing needs further research. [ABSTRACT FROM AUTHOR]