Technological innovation in the biomedical industry is the basis for improving the core competitiveness of the biomedical industry and promoting the high-quality development of the industry. However, ...the technological innovation capacity of China's biomedical industry is not balanced, and there are great differences between regions. Therefore, accurately grasping the status quo of technological innovation in China's biomedical industry and assessing regional differences are of great significance and effect for the country to formulate targeted policies and systems. In view of this, this paper designs a two-stage biomedical industry technological innovation capability evaluation index system from the perspective of the innovation value chain. According to the panel data of China's biomedical industry from 2012 to 2018, a grey relational clustering model based on panel data is constructed and used to evaluate the technological innovation capability of China's biomedicine industry from two dimensions: the level of technological research and development and the ability to transform technological achievements.
Taking visual art intelligence as an entry point, this paper describes the transformation brought by the information age to the expression of visual art. Based on VR technology to build a practice ...system of visual art intelligence, VR positioning technology is used to locate the three-dimensional coordinates of the operator in order to realize the independent positioning of multiple operators in a large space and avoid positioning interference. Through the eye movement multi-channel interaction algorithm based on head-eye synergy, the two-dimensional interaction task in flow field visualization is completed, and then gesture interaction is added to complete the three-dimensional interaction task. The constructed system was implemented in the teaching of art majors at College Z, and the data were analyzed. The results show that the total average scores of innovative theoretical ideas, interactive experience feeling, symbolic integration of creative content and infinite extension of the multidimensional spatial field are 82.42, 83.57, 80.84 and 80.28, respectively. The data show that teachers, students and parents recognize the intelligent system of visual arts and believe that it improves students’ innovative ability in art creation, enhances the interactive experience feeling of visual arts, and provides data support for the continuous research and exploration of contemporary visual arts.
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Whereas freeze-drying is a widely used method to produce porous hydrogel scaffolds, the mechanisms of pore formation involved in this process remained poorly characterized. To explore ...this, we focused on a cross-linked polysaccharide-based hydrogel developed for bone tissue engineering. Scaffolds were first swollen in 0.025% NaCl then freeze-dried at low cooling rate, i.e. −0.1 °C min−1, and finally swollen in aqueous solvents of increasing ionic strength. We found that scaffold’s porous structure is strongly conditioned by the nucleation of ice. Electron cryo-microscopy of frozen scaffolds demonstrates that each pore results from the growth of one to a few ice grains. Most crystals were formed by secondary nucleation since very few nucleating sites were initially present in each scaffold (0.1 nuclei cm−3 °C−1). The polymer chains are rejected in the intergranular space and form a macro-network. Its characteristic length scale coincides with the ice grain size (160 μm) and is several orders of magnitude greater than the mesh size (90 nm) of the cross-linked network. After sublimation, the ice grains are replaced by macro-pores of 280 μm mean size and the resulting dry structure is highly porous, i.e. 93%, as measured by high-resolution X-ray tomography. In the swollen state, the scaffold mean pore size decreases in aqueous solvent of increasing ionic strength (120 µm in 0.025% NaCl and 54 µm in DBPS) but the porosity remains the same, i.e. 29% regardless of the solvent. Finally, cell seeding of dried scaffolds demonstrates that the pores are adequately interconnected to allow homogenous cell distribution.
The fabrication of hydrogel scaffolds is an important research area in tissue engineering. Hydrogels are textured to provide a 3D-framework that is favorable for cell proliferation and/or differentiation. Optimum hydrogel pore size depends on its biological application. Producing porous hydrogels is commonly achieved through freeze-drying. However, the mechanisms of pore formation remain to be fully understood. We carefully analyzed scaffolds of a cross-linked polysaccharide-based hydrogel developed for bone tissue engineering, using state-of-the-art microscopic techniques. Our experimental results evidenced the shaping of hydrogel during the freezing step, through a specific ice-templating mechanism. These findings will guide the strategies for controlling the porous structure of hydrogel scaffolds.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A simple wet chemical process followed by high temperature calcination has been successfully used to coat Li-ion conductive Li4Ti5O12 on the surface of Ni-rich LiNi0.8Co0.1Mn0.1O2. Physicochemical ...characterization results indicate that a Li4Ti5O12 with a thickness of about 2–3 nm was uniformly distributed on the surface of microspheres, without inducing significant change of the structure and morphology. Electrochemical test results show that proper content of Li4Ti5O12 coating layer can greatly improve the cycling performance and rate capability of Ni-rich LiNi0.8Co0.1Mn0.1O2 for the improved Li+ ions diffusion rate and suppressed side reactions between electrode and electrolyte. Notably, the 1 wt% Li4Ti5O12 coated sample exhibits excellent cycling stability with the capacity retention of 75.86% at 1 C after 170 cycles when cycled between 2.7 and 4.3 V at 25 °C, while that is only 39.40% for bare LiNi0.8Co0.1Mn0.1O2.
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Phosphorene is a promising candidate for gas sensing materials. This letter describes our study of the adsorption of SF 6 and SF 6 decomposition gases (SO 2 and H 2 S) on phosphorene. We used first ...principles calculations to explore phosphorene's potential applications as gas sensor to diagnose the state of online gas insulated switchgear (GIS). The calculation results showed that only the adsorption of SO 2 induced a moderate adsorption energy and apparent charge transfer. We further investigated the current-voltage (I-V) relationships before and after gas absorption through the non-equilibrium Green's function method. It was found that only SO 2 induced a dramatic change in the I-V relationships. Therefore, phosphorene appears to be a promising candidate for highly sensitive and selective SF 6 decomposition gas sensors for online GIS diagnosis.
To find out the hidden danger in the industrial production process in time, it is necessary to monitor the health condition of the key components of the mechanical system in operation. However, ...traditional fault diagnosis methods usually adopt manual feature extraction, which not only costs expensively and depends on prior knowledge. Therefore, it is of great significance to study the application of automatic fault identification based on the original vibration signals. Recently, existing studies have shown that most of fault diagnoses are implemented by using deep neural network. Although these methods have achieved satisfactory performances, there are obvious limitations in real applications, that is, the complexity of deep neural network requires a lot of hardware computing resources. This hinders the development of online fault diagnosis tools. To solve this problem, this paper proposes a fault diagnosis model based on lightweight convolutional neural network MobileNet, and realizes an end-to-end intelligent fault classification and diagnosis application. We evaluated the proposed method with the rolling bearing dataset from Western Reserve University. The best average precision, recall and F1 score of ten different bearing health conditions are about 96%, 82% and 88%, respectively. In addition, we also compare the accuracy of the rolling bearing fault diagnosis classification model under the standard ReLU and the improved ReLU. Experimental results show that both obtain good performances, but the improved ReLU reaches the over 96% accuracy more rapidly.
Currently, Internet of Things (IoT) and blockchain technologies are experiencing exponential growth in academia and industry. Generally, IoT is a centralized system whose security and performance ...mainly rely on centralized servers. Therefore, users have to trust the centralized servers; in addition, it is difficult to coordinate external computing resources to improve the performance of IoT. Fortunately, the blockchain may provide this decentralization, high credibility and high security. Consequently, blockchain-based IoT may become a reasonable choice for the design of a decentralized IoT system. In this paper, we propose a novel blockchain-based threshold IoT service system: BeeKeeper. In the BeeKeeper system, servers can process a user's data by performing homomorphic computations on the data without learning anything from them. Furthermore, any node can become a leader's server if the node and the leader desire so. In this way, BeeKeeper's performance can continually increase by attracting external computing resources to join in it. Moreover, malicious nodes can be scrutinized. In addition, BeeKeeper is fault tolerant since a user's BeeKeeper protocol may work smoothly as long as a threshold number of its servers are active and honest. Finally, we deploy BeeKeeper on the Ethereum blockchain and give the corresponding performance evaluation. In our experiments, servers can generate their response with about 107 ms. Moreover, the performance of BeeKeeper mainly depends on the blockchain platform. For instance, the response time is about 22.5 s since the block interval of Ethereum blockchain is about 15 s. In fact, if we use some other blockchain with short block interval, the response time may be obviously short.
A series of flame-retardant epoxy resins (EP) with different content of poly(DOPO substituted dihydroxyl phenyl pentaerythritol diphosphonate) (PFR) were prepared. The PFR was synthesized via the ...polycondensation between 10-(2,5-dihydroxyl phenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-BQ) and pentaerythritol diphosphonate dichloride (SPDPC). The structure of PFR was confirmed by Fourier transform infrared spectroscopy (FTIR) and
1H nuclear magnetic resonance (
1H NMR). The flame retardancy and the thermal stability of the EP/PFR hybrids were investigated by limiting oxygen index (LOI) test and thermogravimetric analysis (TGA) in air. The results showed that the incorporation of PFR into EP can improve the thermal stability dramatically. The mechanical results demonstrated that PFR enhanced failure strain slightly accompanied by a decrease in tensile strength. The thermal oxidative degradation mechanisms of the EP/PFR hybrids were investigated by real time Fourier transform infrared spectra (RTFTIR) and direct pyrolysis/mass (DP-MS) analysis. X-ray photoelectron spectroscopy (XPS) was used to explore chemical components of the residual char of EP and EP/PFR hybrid. DP-MS analysis showed that the degradation process of EP/PFR hybrid was divided into two characteristic temperature regions, attributed to the decomposition of phosphate and aromatic structure.
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In this letter, we took a first principles calculation of five SF 6 decomposition gas molecules (SO 2 , H 2 S, SOF 2 , SO 2 F 2 , and SF 6 ) adsorption on monolayer MoTe 2 . By calculating adsorption ...energy, charge transfer, and work function combined with differential charge density analysis, we predict that MoTe 2 is sensitive and selective to the SO 2 molecule. Furthermore, the total density of states analysis and projected density of states analysis demonstrate that the orbital hybridization is the main reason of the intense charge transfer between the SO 2 molecule and monolayer MoTe 2 . In summary, it can be concluded that MoTe 2 is a promising candidate for SF 6 decomposition gas sensors with high sensitivity and selectivity.
There is still a lack of relevant studies on surgical site infection (SSI) after emergency abdominal surgery (EAS) in China. This study aims to understand the incidence of SSI after EAS in China and ...discuss its risk factors. All adult patients who underwent EAS in 47 hospitals in China from May 1 to 31, 2018, and from May 1 to June 7, 2019, were enrolled in this study. The basic information, perioperative data, and microbial culture results of infected incision were prospectively collected. The primary outcome measure was the incidence of SSI after EAS, and the secondary outcome variables were postoperative length of stay, ICU admission rate, ICU length of stay, 30-day postoperative mortality, and hospitalization cost. Univariate and multivariate logistic regression were used to analyze the risk factors. The results were expressed as the odds ratio and 95% confidence interval. A total of 953 patients age 48.8 (SD: 17.9), male 51.9% with EAS were included in this study: 71 patients (7.5%) developed SSI after surgery. The main pathogen of SSI was Escherichia coli (culture positive rate 29.6%). Patients with SSI had significantly longer overall hospital (p < 0.001) and ICU stays (p < 0.001), significantly higher ICU admissions (p < 0.001), and medical costs (p < 0.001) than patients without SSI. Multivariate logistic regression analysis showed that male (P = 0.010), high blood glucose level (P < 0.001), colorectal surgery (P < 0.001), intestinal obstruction (P = 0.045) and surgical duration (P = 0.007) were risk factors for SSI, whereas laparoscopic surgery (P < 0.001) was a protective factor. This study found a high incidence of SSI after EAS in China. The occurrence of SSI prolongs the patient's hospital stay and increases the medical burden. The study also revealed predictors of SSI after EAS and provides a basis for the development of norms for the prevention of surgical site infection after emergency abdominal surgery.
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