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Objective In recent years, extreme rainfall weather frequently causes urban flooding, leading to many cases of metro engineering project water disasters, significant economic losses and personnel casualties. It is essential to develop scientifically sound anti-backflow measures and construct an effective flood prevention system. However, current research on underground spaces both in China and worldwide primarily focuses on forecasting and risk assessment of flooding disasters, failing to form a comprehensive flood prevention system. Moreover, commonly used anti-backflow measures in metro engineering, such as setting steps and reverse-slopes at metro entrance or equipping with removable flood prevention barriers and sandbags, have drawbacks including the need for long-term personnel monitoring, inconvenient use, and delayed response. Method Through investigation, adhering to the principle of ′prevention as the mainstay and drainage as the supplement′, a comprehensive flood prevention system for metro engineering is summarized, covering aspects of metro stations, interval tunnels, vehicle depots, coordination mechanisms, disaster prevention plans, and design standard improvements. Result & Conclusion Addressing the shortcomings of existing anti-backflow measures, an intelligent flood prevention equipment is proposed. This equipment can manage access, provide on-site manual control, on-site automatic flood prevention, remote control, emergency manual control, and safety assistance. It can be applied to new metro stations, existing station renovations, underground garages, underground shopping malls, ensuring the safety of personnel and property.

Purposes In order to predict the traffic of 5G base stations more accurately and analyze the tidal phenomenon, a traffic prediction method of GAN model with differential algorithm is proposed to improve the gray wolf optimized LSTM. And the modified GAN model is used in the timing control of actual base stations, which can effectively save the energy consumption. Methods First, since GAN is not adaptable to while LSTM is suitable for time series problems, by combining them, the GAN generator optimizes LSTM by differential evolution grey wolf algorithm. Discriminator uses GRU for discriminating, through continuous adversarial training, the generator and discriminator get equilibrium, thus improving the prediction accuracy of 5G base station traffic. Second, because of the poor global search capability of k-means++ al gorithm, the k-means++ algorithm is optimized by using an improved artificial bee colony, and is used to output the optimal base station timing time to achieve the maximum energy saving. Findings The experimental results show that the proposed model has higher prediction accuracy compared with existing models, and the timing control function can greatly save energy consumption.

To further explore the metabolism of Lycium barbarum polysaccharides, the cell wall microstructure of Lycium barbarum fruits in different growth periods was observed by transmission electron microscopy, and the cell wall polysaccharide content and its degrading enzyme activity were extracted by chemical method. The changes of polysaccharide components in cell wall of Lycium barbarum fruits in different growth periods were analyzed by microcopolymer Raman spectroscopy. The correlation between the content of polysaccharide in cell wall and the activity of degrading enzyme was analyzed. The results showed that the changes of cell wall structure mainly occurred during 28~35 d, with the cell wall becoming significantly thinner, pectin degrading, and the cell wall structure gradually collapsing. Cell wall material (CWM) content increased first and then decreased, and water-soluble pectin (WSP) content increased significantly (P

Energy recovery devices can reduce the specific energy consumption and operation cost of reverse osmosis desalination systems, which is an important core energy-saving equipment. In this paper, four combined processes were proposed, including turbine-free single-stage, single-turbine single-stage, dual-turbine two-stage, and single-turbine inter-stage pressurization for reverse osmosis seawater desalination systems, whilst ensuring the same influent flow rate and recovery rate. The whole process routes and equipment selection were also studied. To evaluate the performance of the combined process, the specific energy consumption ratios were analyzed with two different energy consumption ratio analysis methods. The results showed that energy recovery technology can reduce system-specific energy consumption. Optimizing the combination of turbine energy recovery devices, especially the combination process of dual-turbine double-stage desalination system and single-turbine inter-stage pressurized desalination system can significantly reduce the specific energy consumption and overall cost of the system.

In this paper, the contents of 12 mineral elements in 100 samples of four types of takeaway fast food, including porridge and noodles, special snacks, Chinese fast food and Western fast food, sold in Beijing were analyzed by ICP-MS, and the RNI and UL values of the elements were used as the assessment criteria for preliminary dietary nutritional assessment of different age groups. The results showed that the range of mineral element contents in the samples was wide and the degree of dispersion was large. The intakes of Na, I and Cr could meet the daily dietary needs of the whole population in all types of takeaway samples, while the intakes of Ca, Mg and Fe were insufficient. The insufficient intakes of K, Zn, Cu, Mn, Mo and Se were found in some of the samples of some populations. The intakes of the 12 elements showed different degrees of variability among the four types of takeaways, with lower intakes of each element in congee and noodle dishes, and K, Ca, Mg, Zn, Fe, Se and Cr showed significant differences from the other three types. The intake of each element was lower in congee and noodles, which showed significant differences with the other three categories. In addition, the intake of take-away fast food was found to be excessive, with Zn and I exceeding 1.1%~5.3% and 3.6%~14.3%, respectively, in different age groups. The results showed that the long-term take-away population should pay attention to adjusting their dietary structure, balancing the intake of take-away food containing meat, vegetables, legumes, eggs and milk, and appropriately replenishing various types of minerals with insufficient intake. At the same time the health risks of “over-nutrition” brought about by fast food takeaways should be paid attention, and the young minors were the key concern groups.

Objective To analyze the prognostic characteristics of different invasion sites and the risk factors affecting overall prognosis, in patients with pT4b stage colorectal cancer who underwent radical resection and showed no lymph node metastasis （N0） by pathology. Methods The clinical and pathological data of colorectal cancer patients received surgical resection in China National Petroleum Corporation Central Hospital from 2017-01-01 to 2021-12-21 were calculated and followed up to 2022-12-31. The time of operation, the time of local recurrence or distant metastasis and the time of death were recorded. Risk factor analysis was grouped based on whether there was disease progression during follow-up. Prognosis of different groups was compared and logistic binary regression was used to screen for meaningful risk factors. Results Survival analysis showed that the disease-free survival (DFS) of patients with tumor invasion of abdominal wall or omentum was (22.2±3.2) months, DFS of tumor invasion of stomach or intestine was (28.3±5.6) months, DFS of tumor invasion of uterus or adnexal was (35.7±2.6) months, and DFS of tumor invasion of the bladder or ureteral was (30.1±3.4) months, Log-rank P=0.001 among groups. Multivariate analysis showed that the right colon (OR=6.829, 95%CI:1.603-29.093, P=0.009), tumor invasion of abdominal wall, omentum (OR=6.198, 95%CI:1.231-31.210, P=0.027), tumor maximum diameter (OR=0.565, 95%CI:0.365-0.874, P=0.010) were independent factors affecting the progression of colorectal cancer. Conclusion Among colorectal cancer patients with pathological staging pT4bN0M0, patients with tumor invasion of the uterus and appendix have the best prognosis, while patients with invasion of the abdominal wall and omentum have the worst prognosis. Patients with tumors located in the right colon and invading the abdominal wall, omentum, or smaller tumor lesions are more likely to experience regional recurrence or distant metastasis after surgery.

The functional health and stability of the oral and maxillofacial system is one of the basic goals of orthodontic treatment. Currently, it is believed that, in general, the condyle is located in the center of the joint fossa when the mandible is in an intercuspal position (ICP) in healthy normal people. At this time, the function of the temporomandibular joint (TMJ) is stable. Due to orthodontic tooth movement and subsequent occlusal changes, patients with malocclusion may experience related remodeling of the temporomandibular joint, especially changes in the position of the condyle. The position of the mandibular condyle is traditionally evaluated using a condylar position indicator. However, this method lacks consistency in obtaining condylar position changes. In recent years, in the clinical application of orthodontic treatment, cone beam computed tomography (CBCT) has become the first choice for examination. CBCT can accurately measure the interarticular space and determine changes in condylar position. This article reviews the CBCT assessment of condylar position and related research on condylar position changes in patients with malocclusion before and after orthodontic treatment. The literature review results indicate that there are differences in the condylar position of patients with different malocclusions, and the condylar position may also change before and after orthodontic treatment. With a lower radiation dose, CBCT has higher accuracy in evaluating the condylar position in patients with malocclusion who undergo orthodontic treatment, thus promoting further study of the mechanism of condylar position changes in patients with malocclusion in the future and providing more accurate and personalized guidance for patient treatment.

ObjectiveTo investigate the population and chigger mite infection of rodents in Pudong District， Shanghai， so as to provide the scientific basis for the prevention and control of rodents and chigger transmitted diseases.MethodsThe monitoring work was conducted in four points including Xuanqiao， Hangtou， Laogang and Nanhui New Town with night trapping method from 2020 to 2022. Habitats as farmland， wasteland， rural residential areas， and parks were selected. The rodent species were identified and rodent density was calculated. All chigger mites were collected from the earlaps and auricular fossae of the rodents. The species of chigger mites were identified and the chigger mite index was calculated.ResultsA total of 222 rodents were captured. They belonged to 5 species， 4 genera， 2 families and 2 orders， including 4 species， 3 genera， and 1 family of Rodentia and 1 species of Insectivora. M. musculus was the dominant species， with a composition ratio of 54.05%. Total 80 chigger mites were captured， with a detection rate of 36.03%. The total chigger index was 0.36 and Rattus tanezumi held the highest （6.00）， followed by M. musculus （0.48）. There were 3 species of chigger mites， L.deliense， L.scutellare， and L.gaohuense. L.deliense was the dominant specie， accounting for 55.00%.ConclusionThere is a risk of chigger-borne disease transmission in Pudong New Area with M. musculus as the dominant host and L. deliense as the dominant species.

LNG corrugated hoses have better flexible mechanical properties and compliance. However, due to the influence of its outline structure and the large heat transfer coefficient, large heat loss is caused during LNG transportation, with the transportation efficiency reduced. Therefore, the flow and heat transfer characteristics of LNG in the plain tube and the corrugated hoses with 5 types of different structural parameters were analyzed with the numerical simulation method. Meanwhile, the influence laws of the corrugation depth,corrugation pitch and Reynolds number on the heat transfer characteristics of the hoses were explored, and the heat transfer characteristics of the hoses were characterized with the thermal performance evaluation criterion(PEC). The results show that: The corrugated hoses have higher Nusselt number, greater friction coefficient and better heat transfer characteristics than the plain tubes. The Nusselt number in the corrugated hoses increases with the increase of Reynolds number, while the friction coefficient decreases with the increase of Reynolds number and becomes stable at high Reynolds number. Under the same Reynolds number, the Nusselt number of the corrugated hoses increases with the increase of the corrugation depth, but decreases with the increase of the corrugation pitch. Besides, the friction coefficient is proportional to the change of the corrugation depth and pitch, and the corrugation depth has the greatest influence. Generally, the research results could provide theoretical guidance for the engineering application and the structural optimization design of LNG cryogenic corrugated hoses.

With the rapid development of emerging biotechnologies such as high-throughput sequencing, multi-omics and multi-dimensional research models for biological big data have been initiated. Concurrently, the fast-evolving technologies including mathematical modeling, artificial intelligence, cloud computing, blockchain, big data, the Internet of Things, and 5G have enabled the development of digital twin. Digital twin, a model mapping of physical objects, processes, and systems in digital space, has shown great potential in the medical field. Digital twin technology can provide visualized 3D structures for human organs and systems to assist diagnosis and treatment, create a tangible 'skeleton' for data mining in genomics, metabolomics, and phenomics, and simulate processes for chronic disease management, drug development, and clinical trials, thereby advancing the medical field. The aim of the article, therefore, is to review the methods and applications of digital twin in the medical field, with the hope of providing reference for the development of medical digital twin research in China.

Objective To evaluate the application and value of nanocarbon tracer in the surgical treatment of papillary thyroid microcarcinoma (PTMC). Methods Retrospective analysis of clinical and pathological data of 165 PTMC patients who underwent thyroid cancer surgery at Nanjing Jiangbei Hospital from January 2017 to December 2022 was conducted. Patients were divided into the nanocarbon group (n=87) and the conventional group (n=78) based on whether carbon nanoparticles suspension was used during the surgery. Surgical data (such as operation time, blood loss, drainage volume), pathological data (number of lymph nodes and the number of positive nodes), and serological indicators (parathyroid hormone and blood calcium) were compared between the two groups. Results There was no statistically significant difference between the two groups in terms of drainage volume, length of hospital stay, blood loss, and operation time (P＞0.05). The nanocarbon group had a higher number of cleared lymph nodes (7.9±2.1 vs 5.4±1.3，t=9.069，P＜0.01) and positive lymph nodes (2.1±1.1 vs 1.4±1.0，t=4.259，P＜0.01) than the conventional group, and the levels of parathyroid hormone and blood calcium at 1 day and 1 month after surgery were higher in the nanocarbon group compared to the conventional group (P＜0.05). During the outpatient follow-up at 1 month after surgery, both groups had lower serum thyroglobulin values, but the difference was not statistically significant (P＞0.05). Conclusion Nanocarbon tracer can improve the clinical benefits of PTMC surgery and is safe and effective.

Bird striking engines are most likely to cause aircraft damage and accidents in bird strike accidents. In order to study the bird strike airworthiness performance of the first stage compressor rotor of the engine, bird strike tests are conducted on the engine rotor under working conditions. The bird strike test, in which the bird weight, velocity and rotate speed of engine blades are 1 000 g, 195 m/s, 8 525 r/min respectively, is made in a vacuum space. Based on the explicit collision dynamics analysis software PAM-CRASH, a corresponding blade bird strike numerical calculation model is established, and the rationality of the calculation model in this paper is verified by comparing it with experimental results. Also, the ability of engine blades against bird strike in different situations is researched. The results indicate that big bird strike leads to a worse situation compared with medium bird flock and small bird lock. Large deformation appears at the tip of the blades due to the impact at the tip part, while impact at the root and middle of the blades will cause a large concentrated stress around the root of blades, and lead to the fracture of the blade.

The pathophysiological mechanism of traumatic brain injury (TBI) is complex, and the changes of cerebrospinal fluid markers can reflect the changes of brain microenvironment and neurometabolic processes, and are not easily interfered by peripheral factors. Compared with blood markers, they are more stable and reliable. This article reviews the research progress of main cerebrospinal fluid markers in TBI, in order to improve the understanding of the pathogenesis of TBI and achieve precise treatment of TBI.

Objective Geomechanical analysis plays a crucial role in exploring and developing oil and gas reservoirs. However, the study of in-situ stress in the Yijianfang–Yingshan formations of the Middle to Lower Ordovician in the Shunbei oilfield has lagged behind. This paper compares and analyzes the rock mechanics and in-situ stress characteristics of different types of carbonate reservoirs in the Yijianfang-Yingshan formations of the Lower Paleozoic Ordovician in the Shunbei No. 4 block, and explores the control effect of micro-grain structures on the in-situ stress and rock mechanics parameters of carbonate reservoirs. It aims to provide fundamental geological data for the evaluating of ultra-deep carbonate reservoirs in the Shunbei area. Methods This study, based on the spring combination model, determined the rock mechanics and in-situ stress characteristics through rock mechanics experiments and array acoustic logging, and characterized the micro-pore structure of the limestone using casting thin sections and X-ray μ-computed tomography analysis. Results The results indicate that the Young's modulus of the Yijianfang–Yingshan formations ranges from 50 to 89 GPa, the compressive strength from 99 to 136 MPa, and the Poisson's ratio from 0.25 to 0.32. The maximum horizontal principal stress of the formations ranges from 200 to 225 MPa, while the minimum horizontal principal stress ranges from 125 to 160 MPa. Conclusion Significant differences in rock mechanics parameters and in-situ stress exist among different types of carbonate reservoirs in the Yijianfang–Yingshan formations. From Type I to Type III and non-reservoir carbonate rocks, the Young's modulus, compressive strength, and maximum horizontal principal stress increase dramatically, while the Poisson's ratio and minimum horizontal principal stress show little change. Compared to micritic limestone, sandy–bioclastic limestone has larger calcite particles and reduced particle cohesion, resulting in decreased compressive strength and Young's modulus. Some calcite particles appear sub-rounded or rounded with higher three-dimensional particle sphericity, also leading to weaker intergranular engagement and further reduction in compressive strength and Young's modulus. The presence of numerous pores and fractures in sandy-bioclastic limestone facilitates frictional sliding and potential failure along microfractures or particle interfaces, contributing to lower compressive strength and Young's modulus as well. In addition, micritic limestones in the Yijianfang–Yingshan formations are affected by hydrothermal activity, with some dolomite being replaced by quartz, which increases the compressive strength and Young's modulus. The macroscopic mechanical characteristics and rock mechanics parameters of the rock are constrained by the micro-grain structures. The low-value zones of the Young's modulus, compressive strength, and maximum horizontal principal stress in the Yijianfang–Yingshan formations are identified as the advantageous reservoir development zones in the Shunbei No. 4 block.

Superoleophobic refers to the phenomenon that the contact angle (CA) of the oil droplet with low surface tension on the solid surface is greater than 150° as well as the sliding angle (SA) is less than 10°. However, due to the low surface tension of organic liquids, the construction of superoleophobic surfaces was relatively difficult. Inspired by springtail, re-entrant structure has become a breakthrough to solve this problem.Together with surface chemical composition modification and surface roughness, it has been introduced into the design and manufacturing system of superoleophobic surface. Several classical wetting models such as Young model, Wenzel model, Cassie-Baxter model were introduced, the design methods of superoleophobic surfaces were elaborated from the structural structure and chemical composition, and the research progress of superoleophobic surface preparation technologies such as electrospinning, sol-gel method, deposition method, etching method and laser processing was discussed, the oleophobic properties of various surfaces under test liquids with different surface tension were summarized. Finally, the research direction of superoleophobic surface was prospected, that is, low cost, simple operation, environmental friendly and excellent physical and chemical properties of the obtained surfaces. The preparation technology of superoleophobic surfaces would be further explored.

Objective To summarize the efficacy and safety of endoscopic resection of skull base chordoma via the combined oral and nasal approach. Methods The clinical data and follow⁃up data of 192 patients with skull base chordoma admitted to the Department of Otorhinolaryngology, Head and Neck Surgery, Xuanwu Hospital, Capital Medical University from December 2008 to December 2022 were retrospectively analyzed. The surgical efficacy was evaluated according to the degree of tumor resection, the emission of clinical symptoms, the incidence of postoperative complications, and the prognosis. Kaplan ⁃ Meier was used for survival analysis. Results All patients underwent endoscopic resection of skull base chordoma via the combined oral and nasal approach. Among the 192 patients, 80.21% (154/192) achieved imaging total resection (gross total resection group) and 19.79% (38/192) with residual imaging (residual group). Two patients died during perioperative period. Postoperative complications included cerebrospinal fluid leakage [6.77% (13/192)], new nerves dysfunction [6.25% (12/192)], subarachnoid hemorrhage [2.08% (4/192)] and intracranial infection [1.56% (3/192)]. Follow up of 81 (52, 120) months resulted in 57 deaths. The median survival time in the gross total resection group was 7.41 years, while in the residual group it was 4.33 years. The difference in survival time between the 2 groups was statistically significant (χ2 = 23.018, P = 0.002). Conclusions Endoscopic combined oral and nasal approach can effectively remove skull base chordoma, prolong survival time, and have a good prognosis. Surgical gross total resection of tumors is an important indicator for predicting prognosis.

Objective To explore the physiological function of gene for cell devision cycle associated 2 (Cdca2), a highly expressed testis gene, in spermatogenesis and fertility in mice. Methods The expression of Cdca2 in different tissues of mice was detected by Q-PCR and Western blot; Using CRISPR/Cas9 gene editing technology and Cre-loxP mediated recombination system, a mouse strain with Cdca2 tissue specific knockout was constructed; By hematoxylin-eosin(HE) staining and morphological analysis, the effect of CDCA2 deletion on spermatogenic cell morphology at different stages of spermatogenesis was studied; The effects of CDCA2 deletion on sperm motility and motility parameters were detected by an automatic sperm detection and analysis system; The effect of CDCA2 deletion on the fertility of male mice was examined by fertility test. Results Cdca2 was a highly expressed gene in testis; Cdca2 germ cell specific knockout mice were successfully obtained by CRISPR/Cas9 technology and reproductive system; CDCA2 deletion in mice had no statistically significant effect on spermatogenic cells, sperm motility parameters and male fertility at all stages of spermatogenesis. Conclusions Cdca2 is probably not necessary for spermatogenesis and male fertility maintenance in mice.

In order to solve the problem of rapid iterative interaction between multiple versions and services under the cloud native architecture, a full-link grayscale publishing technology scheme for cloud native is designed. Using traffic dyeing technology, an isolated environment from the gateway to all back-end business services is constructed to achieve grayscale publishing supporting multiple versions and multiple services. Flexible and rich gray scale strategy is designed to realize precise control of gray scale publishing. Full-link grayscale publishing capability is implemented through gateways and sidecar module that are relied upon by all back-end business services. Engineering practice shows that this scheme can effectively isolate the environment logically, provide precise control and full link capability, and effectively reduce the impact of demand release and improve the efficiency of online release.

Big Data Knowledge Engineering is the infrastructure of artificial intelligence, a common requirement faced by various industries and fields, and the inevitable path for the digitalization to intelligence. In this paper, we firstly elaborate on the background and connotation of big data knowledge engineering and propose a research framework of “data knowledgeization, knowledge systematization, and knowledge reasoning”. Secondly, we sort out the key technologies of knowledge acquisition and fusion, knowledge representation, and knowledge reasoning and introduce engineering applications in typical scenarios such as smart education, tax risk control, and smart healthcare. Thirdly, we summary the challenges faced by big data knowledge engineering and predict the future research directions including complex big data knowledge acquisition, knowledge+data hybrid learning, and brain-inspired knowledge coding and memorizing. Finally, several suggestions are given by the research: guiding interdisciplinary integration and establishing major and key R&D projects to promote the basic theory and technological breakthroughs of big data knowledge engineering; strengthening communication and cooperation between enterprises and research institutions as well as promoting cutting-edge research results to form application demonstrations, so as to establish an industry-standard system for big data knowledge engineering; exploring school-enterprise cooperation in line with market demands, orienting towards major application needs, and accelerating the landing application of big data knowledge engineering technology in the country's important industries.

Due to the lack of domestic 980 nm pump laser design experience and production process, the key technology of high power 980 nm pumped laser to break through. In this paper, a 980 nm pump laser with 400 mW output power has been successfully developed by using a domestic solution, including the design and implementation of chips, gratings and coupling fibers. By using the all metallized package directly coupled with wedge-shaped fiber and selecting the double grating structure for wavelength locking, the wavelength stability of the 980 nm pumped laser with 400 mW output power in the operating temperature range of -50~75 ℃ can reach 0.01 nm/ ℃. Moreover the 980 nm pump laser has passed the 800 mA charge aging at 75 ℃ for more than 5 000 h. This has laid a foundation for the research of domestic pump lasers with high reliability.

In order to study the nonlinear dynamic characteristics of the curve-face gear transmission system and the influence of parameters on the dynamic characteristics of the system, a nonlinear dynamic model of the curve-face gear system is established. The dimensionless meshing frequency is selected as the control parameter, and the bifurcation diagram, phase diagram, time history diagram and Poincaré diagram are analyzed. The mapping graph is used to study the dynamic characteristics of the system. The results show that the system changes from the non-impact state to the unilateral impact state by jumping bifurcation, and then leads to chaotic motion by continuous doubling bifurcation. When the comprehensive transmission error is increased or the torque is reduced, the non-impact state region of the system shrinks gradually, and the jumping bifurcation value and doubling bifurcation advance, which make the system jump ahead of time. The mode of transition from non-shock to unilateral shock changes, the subharmonic motion region expands gradually and moves forward, the types of motion increase, the number of motion cycles increases, the chaotic motion region expands gradually, and the stability of the system decreases.

With the advancement of China’s electricity spot market construction， it has become a prevailing trend for new energy to participate in the spot market. However， the output uncertainty of new energy debilitates its market competitiveness. As a mature energy storage technology， distributed pumped-storage power plants can cooperate with new energy generation and stabilize its output fluctuations. To this end， a two-stage stochastic optimization model for the participation of a consortium of distributed pumped storage plants and new energy generation in the day-ahead and real-time markets under a dual settlement mechanism in the spot market is investigated. Conditional value-at-risk （CVaR）is introduced to quantify the impact of uncertainty in new energy output and market electricity prices on the joint venture’s revenue， and to optimize the consortium’s bidding in the day-ahead market stage and rolling self-dispatch in the real-time balancing market stage. The example analysis shows that the proposed method can increase the revenue of the joint venture in the spot market. Finally， the impact of the risk preference factor and the storage capacity of the pumped storage plant on the joint venture’s revenue is discussed.

In advanced high-speed fiber optic communication systems, due to the introduction of dense wavelength division multiplexing technology, the signal spectral interval is getting narrower and narrower, and the traditional out-of-band Optical Signal-to-Noise Ratio (OSNR) monitoring technology is no longer accurate. Therefore, further study is required in the low-cost in-band OSNR monitoring scheme. A Deep Neural Network (DNN) link OSNR monitoring scheme for Intensity-Modulation and Direct Detection (IMDD) system is proposed. We used a 5-layer DNN trained from 550 000 datasets to successfully estimate the OSNR of the 2 GBaud On-Off Key (OOK) signal in the range of 5 to 15 dB, and the Mean Absolute Error (MAE) is less than 0.8 dB.

Aiming at the wear failure of tubing string caused by the nonlinear flow-induced vibration（FIV） in high-temperature, high-pressure and high-yield（3H） gas wells, the nonlinear FIV model of tubing string was established using the element method, energy method and Hamilton variational principle, which considered the changes of wellbore trajectory, wellbore temperature/pressure, and contact of casing. A simulation experiment of the tubing string vibration was conducted to verify the correctness and validity of the nonlinear vibration model. Based on the White-Fleisher wear theory, a calculation method for the wear amount and depth of tubing string in 3H gas wells is proposed. The wear unit test is carried out, and the friction coefficient and wear efficiency are determined. On this basis, the influence of production rate, well angle, well section length, packer position and centralizer position on wear characteristics of tubing is systematically analyzed. The safety control methods of tubing string were proposed, namely, which shown that, firstly, with the increase of production rate, the wear life of the string decreases, and there is a sudden value, which can be determine using the analysis method, so that the field production allocation should be far away from the sudden production rate. Secondly, in the well trajectory design, the length of vertical well section should be reduced, and the length of build section and the angle of stable inclined section should be increased. Thirdly, there is an optimal position of packer and centralizer in the field, which is related to the well structure, string structure and downhole tool size, and can be determined by the proposed analysis method to guide the design of packer and centralizer. The research results can effectively improve the service life of tubing string in 3H gas wells.

CFRP composites are widely used in aerospace due to their excellent mechanical properties, however, due to the anisotropy of the individual plies, the electro magnetic interference(EMI) shielding efficiency(SE) for vertically polarized waves of the unidirectional fiber laminates is poor. In order to protect electronics within these equipments from increasingly severe electromagnetic interference, it is particularly important to enhance the electromagnetic shielding efficiency of the CFRP. In this paper, Al particles were introduced and a conductive network was constructed in the CFRP interlaminar region by condensing the Al particles on the prepreg surface. The effects of different Al particle contents on EMI SE and mechanical properties of composites were studied. With the increase of Al particle contents, the electrical conductivity and the EMI SE of CFRP composites increase. When the Al mass fraction in the resin is 33.3%, the in-plane conductivity of the composites increases by 3 orders of magnitude, the EMI SE of the Al particle sandwich CFRP composites is improved by more than 10 dB in the frequency range of 3-17 GHz. With the increase of Al particle contents, the interlaminar shear strength and bending strength of the composites increase first and then decrease. When the Al mass fraction in the resin is 33.3%, the interlaminar shear strength (ILSS) of the composites increases by 5.2% to 80.5 MPa, and when the Al mass fraction in the resin is 50%, the bending strength of the composites increases by 20% to 1441.0 MPa and the bending modulus increases by 10.2% to 101.83 GPa. It can be seen that the mechanical properties and electromagnetic shielding effectiveness of the Al particles sandwich CFRP composite can be improved simutaneously. It is a kind of structure electromagnetic shielding integrated composite with broad application prospects.

This paper proposes a novel Non-linear Camera Assisted-Received Signal Strength (nCA-RSS) algorithm. The basic idea of nCA-RSS is to simultaneously utilize camera and Photo-Diode (PD) to capture visual information and signal strength information to achieve both high coverage and accurate positioning. First, based on single-view geometry theorem, nCA-RSS algorithm estimates incidence angle of visible light based on visual information. Then, based on the estimated incidence angle, nCA-RSS algorithm utilizes signal strength to determine the location of the receiver. Due to the use of visual information, nCA-RSS no longer has orientation limitations. Based on Levenberg-Marquardt, nCA-RSS can use three Light Emitting Diode (LED) to achieve precise 3-Dimensional (3D) positioning. Therefore, compared with perspective n point algorithm, nCA-RSS can achieve high coverage. Simulation results show that nCA-RSS can achieve 80th percentile accuracies of less than 2.5 cm for positioning regardless of the orientation of the receiver.

Deep bite is a common clinical malocclusion that has a great impact on patients’ facial aesthetics and oral function. Bite opening is the key step in the treatment of deep bite, playing a decisive role in the development of mandible and the progress of orthodontic treatment. Torque and tip control during the correction of deep bites is a hot topic in orthodontics. The three-dimensional finite element method can accurately simulate clinical processes and conduct dynamic stress analysis, which provides the basis of the biomechanical mechanism. This paper reviewed the finite element analysis of various orthodontic systems for bite opening to provide a reference for clinical application. The emergence of mini-implants provided a new idea for anchorage control in bite opening. Finite element studies found that high-positioned mini-implants are beneficial for bodily tooth intrusion and proposed the ideal position for force application. For the finite element simulation of the reverse curve archwire, it was found that the intrusion and inclination of the anterior teeth increased with the curve depth of the archwire. The application of clear aligners has also been flourishing, but these forces are still difficult to effectively control. Finite element studies on their attachment design and corresponding tooth movement may be helpful to open the bite quickly and effectively. However, the existing studies still have modeling limitations. The structural simplification, linearization and nonstandard parameter definition of the model reduce model accuracy. Additionally, the existing research mostly focused on initial tooth movement, and studies on long-term tooth movement after bone remodeling are lacking. These studies are needed in the future.

The traditional potassium permanganate consumption (COD) test method is the detection method which has been widely used for many years. It has been applied to the detection of food contact materials and its products because it has some advantages, such as experimental operation, simple experimental principle and low experimental cost. But when dealing with a large number of samples, the traditional COD test method seems to be not very well. The traditional COD test method has some big disadvantages, such as low detection efficiency and high manpower cost investment. Therefore, some COD automatic titrators based on potentiometric titration technology have been invented in recent years. However, this type of COD automatic titrator is fundamentally different from the traditional COD test method in principle. The COD automatic measuring instrument based on color recognition technology can replace manual work while maintaining the same principle with the traditional COD test method, meeting the test requirements on technical indicators, realizing automation and improving the detection efficiency. This paper introduces a kind of COD automatic measuring instrument based on color recognition technology, and improves and optimizes the automatic titrator by experimental data.

Background DSA is an irreplaceable diagnostic method for cerebral vascular disease. It is sensitive to intracranial macrovascular disease, but not to distal blood perfusion. In order to quantitatively assess the perfusion area of the feeding artery, this study is the first to propose an imaging method of the internal carotid artery (ICA) perfusion area relying on deconvolution algorithm and cross⁃correlation (CC) algorithm. Methods Four patients with cerebral vascular disease and 2 healthy subjects who underwent DSA examination in Luwan Branch of Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine from June 2020 to May 2021 were enrolled. The arterial input function (AIF) of the ICA was extracted, and a deconvolution algorithm was used to calculate the time to peak (Tmax) for each pixel. Then the CC algorithm was used to obtain the CC map related to the perfusion of the ICA at each pixel point of the whole brain. Area of interest (ROI) of AIF were randomly selected for 2 healthy subjects, calculated the root mean square error (RMSE) of the CC map for reliability analysis. The CC map was drawn for 4 patients with cerebral vascular disease for validity analysis. Results Reliability analysis showed that the RMSE values of Towne's and lateral views of the CC map and Tmax map of the left and right ICA in a healthy subject were 0.008±0.011, 0.022±0.002, 0.015±0.007, 0.004±0.008, and (0.108±0.181) s, (0.181±0.214) s, (0.301±0.230) s, (0.035±0.092) s; another healthy subject were 0.015±0.023, 0.007±0.011, 0.007±0.011, 0.005±0.012, and (0.172±0.275) s, (0.092±0.174) s, (0.087±0.156) s, (0.079±0.153) s. The averaged RMSE value of Tmax map was lower than the temporal resolution of DSA, indicating that the reliability of the CC map of the AIF value box in different ROIs of the ICA was high. Validity analysis showed that the CC map and Tmax map of the patient with acute ischemic stroke treated by intravenous thrombolysis bridging to mechanical thrombectomy can fully display the perfusion changes of the ICA after successful thrombectomy. Postoperative DSA in the patient with subacute ischemic stroke after endovascular therapy showed recanalization of the occluded artery, while the CC map showed no significant change in the perfusion of the ICA. The DSA of the patient with middle cerebral artery (MCA) stenosis without related ischemic events showed severe MCA stenosis, but the CC map showed that the ICA was well perfused, and no endovascular treatment was required. The DSA of the patient with acute ischemic stroke without MCA stenosis showed no MCA stenosis, but only sparse ICA⁃related perfusion was seen on the CC map. Conclusions The CC map and Tmax map based on DSA images have good reliability in different ROIs of AIF. The CC map can provide quantitative information on the perfusion area of the feeding arteries, which is helpful for accurate diagnosis and appropriate treatment decisions.

ObjectiveTo investigate the psychometric features of MATRICS Consensus Cognitive Battery （MCCB） in adolescents with bipolar disorder， so as to evaluate its appropriateness for the measurement of cognitive deficits in adolescents with bipolar disorder.MethodsAdolescents with bipolar disorder （n=38）， adolescents with major depressive episode （n=40） and healthy controls （n=41） matched on age， sex and educational background were enrolled. Adolescents with bipolar disorder were assessed using Montreal Cognitive Assessment Scale （MoCA） and MCCB at baseline and 2 weeks later， while the rest were only assessed using MCCB at baseline. Thereafter， the psychometric features of MCCB such as internal consistency， test-retest reliability and criterion-related validity， discriminant validity and structural validity were evaluated using Cronbach's α coefficient， Pearson correlation analysis， analysis of covariance and confirmatory factor analysis.Results①The Cronbach's α coefficient of MCCB in adolescents with bipolar disorder was 0.784 at baseline and 0.773 at two weeks later， respectively. ②Among adolescents with bipolar disorder， the test-retest reliability over a two-week interval of each dimension in MCCB ranged from 0.630 to 0.812 （P

Objective To evaluate the significance of sequential therapy concept in the treatment of humeral lateral condyle fracture combined with elbow dislocation in children. Methods A retrospective analysis was performed on the clinical data of 16 children with humeral lateral condyle fracture combined with elbow dislocation who were treated in our hospital under the concept of sequential therapy from January 2010 to December 2020. The conditions of different Jakob classification before and after reduction were observed, the lateral condylar prominence index (LCPI) and the distal humeral intercondylar width (IEW) before and after surgery were measured, and the excellent and good rate of Flynn's elbow score and complications were assessed. Results All cases were followed up for an average of 27.5 (12~37) months. There was no significant difference in Jakob typesⅠandⅡbefore and after reduction, while in Jakob type Ⅲ, statistical difference was observed (P < 0.05). In addition, the pre- and post-operative LCPI and IEW had no significant difference. At the last follow-up, according to Flynn's elbow scale, 9 cases attained excellent therapeutic efficacy, 6 good, and 1 fair, with an excellent and good rate of 93.8%. Conclusion The treatment plan based on the concept of sequential therapy has a proved therapeutic effect in the treatment of children with humeral lateral condyle fracture combined with elbow dislocation, especially for fracture of Jakob type Ⅲ, which is worth clinical promotion.

Objective To analyze the clinical characteristics and survival prognosis of patients with AIDS-related malignant tumor. Methods We retrospectively analyzed the data of 354 patients with AIDS-related malignant tumor. Univariate analysis was conducted by Log rank test and multivariate analysis was conducted by Cox proportional risk regression model. Results The average age of the patients was 54.10±12.96 years old. The ratio of male to female patients was 2.1:1. The number of patients with AIDS complicated with lymphoma was the most, accounting for 28.25%. The 1-, 3- and 5-year survival rates were 78.48%, 62.13% and 55.31%, respectively. Univariate analysis showed that there were statistical differences in prognosis of patients with different types of malignant tumor, age, gender, medical insurance type, number of admissions after diagnosis of AIDS, average length of stay, radiotherapy or not, leaving hospital according to medical advice. Multivariate analysis showed that gender, number of admissions after diagnosis of AIDS, average length of stay, proportion of out-of-pocket and leaving hospital according to medical advice were independent risk factors affecting the survival and prognosis of patients. Conclusion AIDS is easily complicated with lymphoma, lung cancer and cervical cancer. The patients received insufficient anti-tumor courses in hospital.

Aiming at clarifying the corrosion behavior of oil casing materials in high salinity and high temperature annulus protection fluid environment, the corrosion damage sensitivity of oil casing materials under non-stressed and stressed conditions in the simulated oilfield annulus protection fluid environment was evaluated by high temperature and high pressure (HPHT) test system. The micromorphology, cross section characteristics and chemical composition of the product film on the surface of the material were analyzed and characterized by scanning electron microscope and energy dispersive spectrometer. Results showed that the corrosion of the material was relatively worse in the annulus protection liquid without deoxygenation treatment. The corrosion product film was cracked and partially detached, and the cracking of the bottom film layer could be seen at the shedding place. Moreover, the average corrosion rate of P110 material was up to 3.83 mm/a. Observing the cross section could find the cracking on the surface of the double film layer was limited to the corrosion product film, and the substate material was not involved. The material was uniformly corroded and thinned. Furthermore, after deoxygenation treatment, the erosion of the annulus protection fluid decreased significantly, and the corrosion rate of P110 material decreased by 80%. Generally, P110 and P110SS were insensitive to stress corrosion cracking under the synergistic effect of high temperature and high pressure annulus protection fluid without deoxygenation treatment environment and loading stress, and corrosion thinning was the main corrosion damage mode of P110 oil casing material.

α-synucleinopathies are a group of common neurodegenerative diseases. Once diagnosed, the disease's pathology is already in the middle or late stages, and the best timing for disease modification therapy is missed. Thus, it is very important to explore the early warning signs or early markers of α-synucleinopathies. Isolated rapid eye movement behavior disorder (iRBD) is the prodromal phase of α-synucleinopathies and may serve as an early warning for future transforming into α-synucleinopathies at this stage. The early warning mechanisms for the iRBD transforming into α-synucleinopathies in terms of non-motor symptoms, neuroimaging markers, neuro biological markers, and genetics are illustrated through perspective studies.

BACKGROUND Stable chlorine isotope, as an effective tracer, can indicate the water evolution and explore the changes of the geological environment. It has a wide application prospect in earth science. The continuous flow isotope ratio mass spectrometry (CF-IRMS) method has been widely used in the determination of stable isotopes due to the advantages of smaller sample size and higher sensitivity. As a volatile gas, methyl chloride easily escapes during the reaction and the test pipeline, causing sample loss. How to achieve the separation and purification of CH3Cl and improve the conversion rate of CH3Cl of the samples in the reaction and analysis is the key to successful determination of stable chlorine isotopes by CF-IRMS. OBJECTIVES To understand the influencing factors for the determination of CH3Cl by CF-IRMS. METHODS The international standard material of chlorine isotope (ISL-354) was chosen as the standard material. The determination method of chlorine stable isotope content in groundwater was studied by using stable isotope ratio mass spectrometer (IRMS) analysis system combined with gas chromatography (GC) separation technology. Three types of samples from analytical pure, standard, and groundwater were chosen. RESULTS By adopting the combined sampling method of GC manual injection and dual-channel reference gas injection, the loss of methyl chloride during the reaction and testing process was reduced, the concentration of methyl chloride during the online analysis was guaranteed, and better test accuracy was obtained. The results showed that the standard deviation of the 37Cl/35Cl ratio of the samples determined by this method was within the range of 0.20‰. The error of the results from different laboratories was less than 0.035‰, which satisfied the requirement of 0.5‰ reproducibility of geological samples. Parameters such as light, temperature, sulfate removal, continuous helium flow and split ratio were the major factors affecting the test accuracy in the experiment. The influence of these parameters should be strictly controlled in the experiment to ensure the accuracy of this method. CONCLUSIONS This method has the advantages of simple pretreatment, small sample consumption, large number of test samples and short test period, which can improve the efficiency of the analytical methods of the chlorine stable isotope of groundwater inorganics.

Multilingual neural machine translation (mNMT) leverages a single encoder-decoder model for translations in multiple language pairs.mNMT can encourage knowledge transfer among related languages,improve low-resource translation and enable zero-shot translation.However,the existing mNMT models are weak in modeling language diversity and perform poor zero-shot translation.To solve the above problems,we first propose a variable dimension bilingual adapter based on the existing adapter architecture.The bilingual adapters are introduced in-between each two Transformer sub-layers to extract language-pair-specific features and the language-pair-specific capacity in the encoder or the decoder can be altered by changing the inner dimension of adapters.We then propose a shared monolingual adapter to model unique features for each language.Experiments on IWSLT dataset show that the proposed model remarkably outperforms the multilingual baseline model and the monolingual adapter can improve the zero-shot translation without deteriorating the performance of multilingual translation.

ObjectiveTo establish a method for determination of the content of chloramphenicol in milk powder by liquid chromatography-mass spectrometry, and apply it to test the uniformity and stability of reference material and determine the value.MethodsThe milk powder was reconstituted by adding water, extracted with ethyl acetate, degreased with n-hexane, extracted with ethyl acetate again, and finally quantified by the isotope internal standard method.ResultsChloramphenicol had a good linear relationship in the range of 0.4-4.0 ng/mL, the correlation coefficient was 0.999, the average recovery rate was 100.5%, the relative standard deviation was 1.1%-3.2% (n=6), and this method had a weak matrix effect in milk matrix.ConclusionThe method is accurate and reliable, and can be used for the determination of reference materials. After jointly determination by 11 laboratories, the characteristic value and the expanded uncertainty (k=2) of the reference material for the analysis of chloramphenicol residues in milk powder are (1.92±0.30) μg/kg and (5.65±0.53) μg/kg.

At present, there is a lack of imaging methods to monitor demyelination and myelin regeneration of central nervous system demyelinating diseases. All kinds of MRI techniques are used to measure demyelination indirectly and are vulnerable to other interference factors. PET is an imaging technique that can image central nervous system diseases at the molecular level. It can realize real⁃time imaging of function, metabolism, biochemistry and make up for the limitations of MRI. PET myelin imaging tracers have developed rapidly in recent years. There are currently three types of PET tracers targeting myelin: congo red derivatives, diphenylethylene derivatives and sulforaphane derivatives. The new multimodal medical imaging technology PET/MRI combines the advantages of PET molecular level imaging and MRI high soft tissue resolution to realize real⁃time fusion of anatomical structure and functional, metabolic, biochemical images. In the future, it may become an effective means to monitor demyelinating lesions of the central nervous system.

It has become increasingly common for tourists to share their personal travel experiences on social media. This user-generated content with spatial references provides a rich database for tracing the evolution of the cognitive image of a tourism destination over a long period of time. This is helpful for local authorities to improve destination management and marketing by prompting image adjustment and tourism product optimization to satisfy tourists' expectations. In this study, data on online travels on Ctrip.com, one of the most popular tourism websites in China, were collected and analyzed to reveal the spatiotemporal evolution of the cognitive image of Chengdu from 2000 to 2019. Based on a specific tourism-related lexicon, keywords were identified and grouped in a list, following a framework comprising six dimensions: tourism attraction, tourism leisure and entertainment, public infrastructure, tourism infrastructure, tourism environment, and local atmosphere. The six dimensions were further divided into 18 sub-dimensions. Under this framework, the general trends and spatiotemporal evolution characteristics of Chengdu's cognitive image during this period were analyzed. Specifically, changes in the shares of identified keywords related to the six dimensions during the period explained the general trend characteristics, while changes in the standard deviational ellipse (SDE) of the distribution of identified keywords with spatial reference, together with changes in the shares of identified keywords related to the 18 sub-dimensions in detail, were adopted to vividly show the spatiotemporal evolution of Chengdu's cognitive image. Our findings revealed that Chengdu's cognitive image has experienced obvious spatiotemporal evolution across different sub-dimensions over the past 20 years. Generally, the cognitive image has became substantial during this period, with a continuous increase in the total share of identified keywords related to the cognitive image of online travels. In addition, the shares of keywords related to the six dimensions and 18 sub-dimensions varied across different stages. Particularly, the spatiotemporal evolution shows that (1) there is an evident shift from sightseeing tourism to experience tourism, as SDE shifts toward the southeastern urban area and the share of identified keywords highly related to experience consumption increases; (2) the city tends to be more "leisurely and carefree" in tourism, as SDE tends to be more concentrated in the urban area with a relatively high density of leisure attractions; and (3) the cognitive image responds to natural hazards promptly, as the size and directions of SDE vary accordingly, and the share of identified keywords related to public infrastructure, tourism infrastructure, and tourism environment reached a peak after the Wenchuan earthquake. Based on our findings, the mechanism forming Chengdu's cognitive image was further discussed from the perspectives of government, residents, and commercial organizations. Methodologically, this study proposes an approach based on text mining and analysis of online travel, typical spatial big data generated by tourists, to examine the cognitive image, which could be applied to other tourism destinations. Moreover, the mechanism framework based on the Chengdu case provides recommendations on tourism destination image management and marketing to improve responses to tourists' changing expectations regarding other tourism destinations.

ObjectiveTo explore the effect of mindfulness-based childbirth on pregnant women's anxiety and depression， and to provide references for related psychological intervention.MethodsA total of 80 pregnant women who attended the obstetrics department of the Third People's Hospital of Mianyang from October 2018 to March 2019 and met the diagnostic criteria of mild to moderate anxiety and depression in the Diagnostic and Statistical Manual of Mental Disorders， fifth edition （DSM-5） were selected， and they were divided into two groups by random number table method， each with 40 cases. Both groups received regular mental health education. On this basis， experimental group received mindfulness-based childbirth training for 8 times， once a week. Meantime， all pregnant women were assessed using Patient Health Questionnaire-9 item （PHQ-9） and Generalized Anxiety Disorder Scale （GAD-7） at the baseline and after intervention.ResultsAt the baseline and after intervention， the scores of PHQ-9 ［（6.95±1.40） vs. （2.10±1.34）， P

ObjectiveTo analyze the etiological characteristics of strains isolated from Vibrio parahaemolyticus food poisoning incidents occurred in Zibo in 2019.MethodsSerotyping and virulent genes (tlh, tdh, trh)were detected by real-time fluorescent polymerase chain reaction, antibiotic sensitivity was examined by broth microdilution method and pulsed field gel electrophoresis (PFGE) were applied to Vibrio parahaemolyticus.ResultsThe 9 strains collected from patients were all pandemic O3∶K6, and the virulence genes were tlh+ tdh+ trh-. The 2 strains collected from environmental samples were O8∶K22 and O1∶K32, and the virulence genes were all tlh+ tdh-trh-. All strains were resistant to cefazolin, and partially resistant to ampicillin and trimethoprim/sulfametho-xazole. There were 2 strains even showed multiple resistance to these three antibiotics, while all strains were sensitive to the other antibiotics. The PFGE homology from the same incident was high.ConclusionThe strains collected from patients in the 4 incidents were all pandemic O3∶K6 and the virulence genes were tdh+, some of which showed multi-antibiotic resistance, and the isolates from the same outbreak had high homology suggesting that they had been exposed to the same pollution source. The supervision of pollution sources should be strengthened to reduce the occurrence of foodborne diseases.

Orthodontic tooth movement is a complex physiological process based on periodontal tissue remodeling. Numerous factors, such as the anatomical characteristics of oral and maxillofacial complications, occlusal interference, mechanical factors and systematic factors, may play critical roles in orthodontic tooth movement, leading to tooth movement difficulty. In recent years, many scholars have focused on factors related to tooth movement difficulty, but current research mostly involves animal experiments and retrospective studies. Clinical trials of high-quality and evidence-based medicine studies are required. Although no sound theory system is available that is universally recognized and the mechanism of many factors remains debatable, alveolar bone defects, the maxillary sinus, the gingiva, tooth ankylosis, bone islands and friction may cause orthodontic tooth movement. Understanding the factors related to the difficulty of orthodontic tooth movement is advantageous to develop a more comprehensive personalized treatment plan for patients and achieve more efficient and safer tooth movement. In this paper, the current factors related to orthodontic tooth movement are reviewed to provide references for clinical orthodontic treatment.

Emerging infectious disease is characterized by sudden and rapid spread, and failure to curb its development in the first place would pose a serious threat to social stability and human health. The hierarchical medical system can realize rapid triage, better separate infectious patients, suspected patients and non-infectious patients, and optimize diagnosis, treatment and nursing work. Taking COVID-19 epidemic as an example, this paper will discuss the present situation of the hierarchical medical system in control and nursing management of sudden infectious diseases, summarize the problems existing in current graded diagnosis and treatment system of China, and propose proposals to promote the development and improvement of the hierarchical medical system. (突发性传染病具有发生突然、传播速度快等特点, 若不能在第一时间采取措施遏制其发展, 将会对社会稳定和人类健康构成严重威胁。分级诊疗制度可以实现快速分诊, 将传染性患者、疑似患者、非传染性患者分开, 优化诊疗、护理工作流程。本研究以新型冠状病毒肺炎疫情为例, 总结分级诊疗制度在突发性传染病护理工作中研究进展, 分析我国目前分级诊疗制度存在的问题, 并提出促进分级诊疗制度发展和完善的刍议。)

As one of the most promising nanofiller, carbon nanotube has attracted more and more attention due to its extraordinary stiffness and strength. While it is not feasible to obtain the effects of carbon nanotubes on the mechanical properties of composites by solely relying on experimental methods, cleaving and analysing the influence of various parameters of carbon nanotubes on the mechanical properties of composites through numerical simulation methods has become a tendency. Based on the morphology of carbon nanotubes, the nano-meso scale model was proposed. Then three numerical simulation methods were classified depending on the differences between the way of modelling and the objects of discussing. In the end, the influencing law of carbon nanotubes on the mechanical properties of composites was reviewed from two aspects(intrinsic properties of carbon nanotubes, content and distribution of carbon nanotubes), which is expected to provide support to the credibility of results from numerical simulation method. In addition, due to the variety of numerical simulation methods and the diversity of carbon nanotube variables, the numerical simulation research of carbon nanotubes reinforced FRP composites still has great potential.

The research on the damage degree of the key parts of civil aircraft impacted by UAV is a new hot issue in the field of civil aviation. It is the first time that rocket sled test is proposed to evaluate the safety of UAV colliding with civil aircraft. Through the research on collision speed, collision position, UAV attitude and parameter measurement, the technical scheme of collision is designed, and the design of rocket sled, trajectory control design, strength check and test scheme are discussed, and the test verification and simulation calculation are carried out. The results show that: the rocket sled collision test scheme designed in this paper is feasible, which can realize continuous multi-point collision on a single trajectory and record the whole process of multi angle, full coverage and high stability. It can provide the necessary technical reference for the subsequent similar collision tests, and the multiple impact tests also provide effective test data for the safety evaluation of UAV collision with civil aircraft.

The three-dimensional (3D) woven composites have the advantages of strong structural design ability, overall near-net shape of complex components and high impact damage tolerance, and have become the focus of the development of new materials in the aerospace industry. In recent years, the structural design, micro-modelling and performance analysis of 3D woven composites have been rapidly developed and achieved substantial achievement. The development of multi-axial woven structures, fine modeling, and automated continuous production are the development trends of 3D woven composites. In this paper, the structural characteristics of typical 3D woven preforms were introduced. The quasi-static mechanical properties of 3D woven composites with different structures were discussed. The research progress of the micro-structure modelling, theoretical analysis and numerical simulation of 3D woven composite materials were reviewed. The typical applications of 3D woven composite materials in aerospace were listed, which can provide reference for the application research of 3D woven composite materials.

Objective To learn about past experiences in studying ideological and political theory courses of doctoral students in Peking Union Medical College and the actual teaching outcomes of Selected Readings of Marxist Classics after the implementation of the teaching reform. Methods Two sets of questionnaires were distributed to 530 MD candidates of Grade 2019 before and after the course in order to investigate and compare their cognition, attitude and evaluation. Results In the pre-course survey, 462 valid questionnaires were recovered, and the recovery rate was 87.17%. In the after-course survey, 466 effective questionnaires were recovered, and the recovery rate was 87.92%. Most students' recognized the significance of this course and were satisfied with the teaching methods and assessment methods. Conclusions Medical students have a good reading and learning experience in this course. However, it is required to continuously strengthen humanistic care in ideological and political teaching to enhance students' sense of gain and further improve their political and moral qualities from the perspective of cognition, feeling and action.

According to the structure and transmission principle of the dual shock wave sleeve movable tooth transmission，the equation of central tooth profile has been derived. On the premise that the working tooth profile of the center wheel does not interfere，the relationship between structural parameters is established. Considering the nonlinear relationship between the load and deformation and the influence of the hollow degree of the movable tooth on the deformation，the nonlinear mechanical model of meshing pair is established to analysis the nonlinear meshing force，changing law and influencing factors of each meshing pair. A non-Hertz contact analysis model is established for the structural characteristics of finite long line contact meshing of each meshing pair of the sleeve，and the effective contact area and contact fatigue stress of each mesh pair are solved by numerical method. The contact fatigue strength of each mesh pair and the bending fatigue strength of the pin are analyzed. The results show that the relationship of structural parameters and the influence factors of meshing force provide reference for the design of double shock sleeve movable tooth transmission，by using the non-Hertz contact model and the nonlinear mechanical model， which take into account the hollowness， the error caused by simplification based on linear elasticity and hertz theory can be reduced， and the strength calculation is more in line with practical situation.

[Objectives] The mechanical impedance of foundations can directly affect the stealth performance of underwater structures,which is commonly obtained by finite element simulation. However, this method is usually very time-consuming and inefficient when applied directly to optimal design. In order to enhance the efficiency,surrogate model technology is used to take the place of computer simulation.[Methods] The mechanical impedance of a typical underwater foundation is studied. The comparison among support vector regression(SVR)method,back propagation neural network(BPNN) method,radial basis function(RBF)method and Kriging model is conducted for their fitting accuracy. Besides,a data preprocessing method is put forward by combining the practical engineering requirement and characteristics of mechanical impedance. The effect of the data preprocessing method on the fitting accuracy of the surrogate model is studied.[Results] According to the calculated results,different surrogate models have different accuracy in fitting the mechanical impedance of the foundation. And the kriging model achieves the best results among four surrogate models. Compared with the initial model,the data preprocessing method has increased the normalized root mean square error and the normalized maximum absolute error by 9.80% and 15.43% respectively to the modified model.[Conclusions] The kriging model has the best applicability on fitting the parameter input-impedance output mapping. And the proposed data preprocessing method can be used to improve the accuracy of the surrogate model.

An improved RSM was proposed to improve the computational efficiency and accuracy of contact fatigue fuzzy reliability analysis of double shock sleeve movable teeth transmission.Based on fuzzy theory,an improved RSM model is established by combining intelligent algorithm and reliability analysis method.Based on the theory of stress-strength interference,the interference reliability model is established with moment,elastic modulus,Poisson’s ratio and working tooth length are taken as input random variables and contact strength of meshing pair is taken as input fuzzy variables.Fuzzy reliability is calculated by different methods,and the distribution characteristics and fuzzy reliability of each response result are obtained.The comparison shows that the improved RSM improves the speed and accuracy of the calculation.