Search

In the process of grain storage, the use of low-temperature grain storage technology can effectively reduce grain losses during storage and ensure grain quality, which is of great significance for maintaining a stable grain supply. Radiative cooling materials, as a new energy-free cooling technology, achieve cooling by radiating heat in the form of electromagnetic waves into outer space. This approach can address issues associated with traditional cooling methods, such as high energy consumption and high chemical oxygen demand (COD) emissions, offering a green and environmentally friendly new approach to low-temperature grain storage. This paper explained the working principle of polymer-based radiative cooling materials and systematically introduced the composition and selection criteria of polymer-based radiative cooling systems. It also categorized and summarized polymer-based radiative cooling materials according to their structural characteristics. The existing problems with different structured radiative cooling materials, as well as future research directions, were also analyzed. This provides a certain research framework for applying radiative cooling materials to grain storage facilities to achieve low-temperature grain storage.

Objective To explore the efficacy and advantages of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods A total of 9 patients with complex intracranial aneurysms who underwent intracranial-intracranial bypass in Xiangya Hospital of Central South University from February 2014 to May 2020 were included, and were treated with grafts bypass or reimplantation of recipient arteries. All cases underwent CTA or DSA to detect the patent of grafts, whether aneurysms were completely clipped or resected and aneurysms recurrence occurred during the follow-up. Modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at discharge and during the follow - up. Results Radial artery (RA) or great saphenous vein (GSV) was used for interposition in 4 cases, and recipient arteries were used for reimplantation in 5 cases. Of 4 cases of interposition, the cavernous sinus seoment of internal carotid artery (ICA)-GSV-ICA bypass was adopted in one case, middle cerebral artery (MCA) M2-RA-M2 bypass in one case, anterior cerebral artery (ACA) A3-GSV-A3 bypass in one case, posterior cerebral artery (PCA) P2 -RA -P2 bypass in one case. Of 5 cases of reimplantation, MCA M2 inferior trunk was reimplanted to M2 superior trunk in one case, ACA A3 was reimplanted to contralateral A3 in 2 cases, the posterior inferior cerebellar artery (PICA) was reimplanted to the anterior inferior cerebellar artery (AICA) in 2 cases. CTA in 3 d postoperatively showed all cases grafts were patent and aneurysms disappeared. After 3 months of discharge, 2 were lost to follow-up. The other 7 cases kept the patency of grafts and no new aneurysms, and were constantly followed up, with an average follow-up time of 30.71 months, and mRS score was 1 or lower. Conclusions Intracranial - intracranial bypass can be applied for complex intracranial aneurysms that are difficult for conventional surgical treatment to solve. Compared with extracranial - intracranial bypass, its grafts are shorter and its hemodynamics features are more in line with physiological conditions.

ObjectiveTo analyze the epidemiological characteristics of tetrodotoxin poisoning events in China from 2011 to 2020 and provide a scientific basis for precise measures to prevent and control tetrodotoxin poisoning.MethodsDescriptive epidemiological methods were used to analyze the epidemiological characteristics of tetrodotoxin poisoning incidents reported through the National Foodborne Disease Outbreak Monitoring System from 2011 to 2020.ResultsFrom 2011 to 2020， 92 cases of tetrodotoxin poisoning reports were received through the National Foodborne Disease Outbreak Monitoring System； 339 people were poisoned and 15 were dead， with a case fatality rate of 4.4%. Tetrodotoxin poisoning was mainly concentrated in the coastal areas of China. The food carriers of tetrodotoxin included pufferfish （71.7%， 66/92）， dried pufferfish （13.0%， 12/92）， Nassariidae （7.6%， 7/92）， horseshoe crabs （5.4%， 5/92）， and Acentrogobius nebulosus （2.2%， 2/92）. Each year， a high incidence of poisoning occurs from March to April.ConclusionTo effectively prevent and control tetrodotoxin poisoning， it is necessary to establish a method for detecting tetrodotoxins in biological samples， improve the ability to identify the pathogenic factors of tetrodotoxin poisoning， strengthen the supervision and popularization of science in the circulation process， and change the dietary habits of people who eat wild pufferfish.

ObjectiveTo obtain the occurrence time and regional distribution characteristics， place of occurrence， high-risk food and risk factors， the epidemiological characteristics of foodborne disease outbreaks caused by Vibrio parahaemolyticus from 2010 to 2020 in China’s Mainland was analyzed.MethodsThe data of foodborne disease outbreaks caused by Vibrio parahaemolyticus were collected from China disease outbreak surveillance system from 2010 to 2020 were analyzed statistically.ResultsFrom 2010 to 2020， a total of 1 772 outbreaks of foodborne diseases caused by Vibrio parahaemolyticus were reported， with a total of 27 212 cases， 5 944 hospitalized cases and 2 deaths. The peak time was from July to September. The incidence in developed areas （28.8 cases/million people） was higher than that in underdeveloped areas （8.2 cases/million people）， and the incidence in coastal areas （31.7 cases/million people） was higher than that in inland areas （9.2 cases/million people）. The main causes were aquatic food （61.2%） and meat （25.3%）. Hotels and restaurants accounted for 49.6% of the total. The main contamination links were incomplete cooking of aquatic food and raw and cooked cross-contamination of ready-to-eat meat and vegetable food.ConclusionIn order to reduce the risk of foodborne diseases caused by Vibrio parahaemolyticus， it is important to strengthen the supervision of processing and storage of aquatic food and meat in catering service places.

ObjectiveTo trace Bacillus cereus （B. cereus） from foodborne disease outbreaks toidentify pathogens and cut off transmission.MethodsPulsed-field gel electrophoresis （PFGE） was performed. Furthermore， 12 isolates of B. cereus were subjected to PFGE. Subsequently， whole-genome sequencing （WGS） analysis was conducted on ten of these isolates. The WGS data were analyzed and assembled using BioNumerics software. Multilocus sequence typing （MLST）， virulence gene profiles， and single nucleotide polymorphisms （SNPs） were analyzed using assembled sequences.ResultsPFGE analysis classified the 12 B. cereus strains into nine pulsotypes. The three B. cereus isolates with the same PFGE pattern belonged to ST1435， and there were only three SNPs in the three ST1435 strains. The two B. cereus isolates with the same PFGE patterns were ST24 with one SNP between them， and the two ST24 isolates harbored hlbACD. These results indicate that the B. cereus isolates belonged to the same clone. The remaining three B. cereus strains also contained hlbACD.ConclusionFood-borne illness events caused by B. cereus are complex and are sources of contamination. Therefore， it will be necessary to strengthen the hygiene surveillance of food sources and workers and to pay more attention to cleaning and disinfecting environments and facilities， which will be important for preventing and controlling foodborne diseases.

A conceptual design of a passive core cooling system (PCCS) was proposed in order to removal residual core heat during accident scenarios. Strong coupling feedback effect exists between natural convective heat transfer of the PCCS and the temperature distribution within the reactor core, which has a significant impact on the heat removal performance of the PCCS and the peak fuel temperature. An integral computational model dedicated to micro gas-cooled reactor, which includes both the PCCS and the reactor core, was developed. Comparisons of results predicted by this model and reference results of two benchmark problem, i.e. exercises of MHTGR and natural convection in a square cavity, show a satisfactory agreement, which thus validate the model. Thereafter, in order to explore the operational characteristics of the PCCS proposed in this work as well as the temperature response of the reactor core, and to assess its mitigative performance during accident scenario, this CFD model was then employed to analyze both the steady state under normal operation condition and the pressurized-loss-of-forced-cooling (PLOFC) accident. The calculation results show that the natural circulation of air is steady and regular during normal operation. The heat loss due to the PCCS is acceptably small, which will not lead to significant impact on the core temperature. During the PLOFC accident, the heat removal power of the PCCS is high in the early phase, whereas its performance gradually decreases as the temperature of the reactor vessel decreases in the long term. In general, the PCCS can effectively remove the residual core heat, thus maintaining the reactor integrity. Consequently, the integral CFD model created in this work can be applied to the design and the safety analysis of the PCCS for the micro gas-cooled reactor.

Biological aerosols are a special type of aerosols in the atmosphere, which have carcinogenic and teratogenic properties. Real-time detection and identification of biological aerosols is the prerequisite for biological warning and forecasting. The design of bipolar time-of-flight (TOF) mass analyzer is required to realize miniaturized vehicle bioaerosol mass spectrometer, with the mass range above 300 and mass spectrometry resolution at least 500. In this study, the exponential pulse delay elicitation technique was applied to the design of miniaturized TOF. Combined with SIMION 2020 software, the particle flight trajectory under the condition that the velocity dispersion was a Gaussian distribution with a peak value of 800 m/s and a spatial dispersion of 0.3 mm were simulated. The particle swarm optimization algorithm (PSO) was used to automatically optimize the voltage and delay time of the TOF. Under the optimized delay time of 130 ns, the resolution of more than 500 could be achieved in the full mass range even if the spatial dispersion and energy dispersion were in extreme cases, and mass deviation between different particles could be controlled within 0.4 u. The impact of normal square wave pulse delay extraction and exponential pulse delay extraction on the resolution of ions formed by a single particle was compared and analyzed. The results showed that exponential pulse delay extraction improves the resolution in the full mass range significantly better than square wave pulse. The effect of particle ionization position on mass spectrometry resolution was simulated when the particle was in the center of the spot and at the limit of 0.15 mm to left and right of the spot. The result showed that the resolution was different, but still better than 500. The detection of black carbon particles showed that the miniaturized TOF could obtain a resolution of more than 500 in the full mass range, which met the resolution requirements of the vehicle bioaerosol mass spectrometer. Although the flight length of the small TOF is 67% of that of SPAMS 0525, the resolution could reach more than 1.2-1.7 times due to the use of exponential pulse delay extraction technology. This study provides a design for a small time-of-flight mass analyzer, and indicates that there is still room for further reduction the size of time-of-flight mass analyzer for the miniaturized bioaerosol mass spectrometry. This study lays a research foundation for further reduction the volume of the subsequent bioaerosol mass spectrometer.

As the cornerstone of the development of the computational tool for the coupled neutronics and thermal-hydraulics analysis dedicated to the micro gas-cooled reactor, neutronic diffusion solver was developed in this work based on the generic 3D finite-element CFD code COMSOL Multiphysics by taking advantage of its equation-based modeling functionality “coefficient form PDE interface”. The steady-state and transient neutronic diffusion equations are solved using the eigenvalue solver and transient solver of this code, respectively. The neutronic diffusion solver developed in this work was firstly validated against two benchmark problems, i.e. 2D-TWIGL and 3D IAEA PWR problems respectively. The comparison of the calculation results of this solve with the reference values offered by the corresponding benchmark problems is satisfactory. Thereafter, this neutronic diffusion solve was applied to the micro gas-cooled reactor criticality analysis, with the group constants (including two-group and 25-group) generated by the Monte-Carlo code RMC. The calculation results of neutronic diffusion were also compared with the reference values derived by the Monte-Carlo transport calculations using the RMC code based on both continuous-energy-spectrum and multi-group methods. In general, the results obtained by solving both the two-group or 25-group neutronic diffusion equations, such as effective multiplication factor and three-dimension power distribution, can match well with the corresponding multi-group Monte-Carlo simulation. Whereas when comparing with the continuous-energy-spectrum MonteCarlo results, adopting the 25 energy groups is able to gain better accuracy in contrast to the two energy groups, indicating that the energy-group division has a significant impact on the neutronics for the micro gas-cooled reactor. The accuracy of prediction can be improved by adopting a more sophisticated energy group structure. However, the required computational source and time will dramatically increase with the number of energy groups.

ObjectiveTo analyze the epidemiological characteristics of foodborne disease outbreaks caused by takeaway in China’s Mainland from 2010 to 2020， and put forward relevant regulatory suggestions.MethodsThrough the National Foodborne Disease Outbreak Monitoring System， the data of foodborne disease outbreaks caused by takeaway in China’s Mainland from 2010 to 2020 were collected and analyzed， and descriptive epidemiological characteristics were performed.ResultsA total of 549 foodborne disease outbreaks caused by takeaway were reported in China’s Mainland （except Tibet Autonomous Region） from 2010 to 2020， resulting in 9 285 illnesses and 2 deaths. The largest number of outbreaks and illnesses was in the third quarter， accounting for 41.53% and 44.58% of the total respectively. Except the unknown pathogenic factors， the number of outbreaks and illnesses caused by microbial pathogenic factors were the highest， accounting for 39.16% and 60.26% of the total respectively. Except the unknown suspected food， the number of outbreaks and illnesses caused by mixed food and multiple food were higher， accounting for 21.86% and 15.12% of the outbreaks respectively， and accounting for 20.58% and 13.10% of the number of illnesses respectively. Except the unknown food source， the top 3 food source were school canteens， collective dining delivery units/central kitchens and fast food restaurants， the number of outbreaks accounted for 20.04%， 15.66% and 15.48% respectively， and the number of illnesses accounted for 35.30%， 17.52% and 10.57% respectively. Except the multiple factors and unknown factors， the number of outbreaks caused by improper storage were the highest accounting for 8.74%， and the number of illnesses caused by improper processing accounted for 7.74%.ConclusionMicrobial growth and reproduction due to improper storage and processing is the major cause of foodborne disease outbreaks caused by takeaway. It is suggested that the food safety supervision and administration departments should strengthen the whole process supervision and management of takeaway， establish and ensure catering services strictly abide by the good hygiene operations according to food raw in materials， production， transportation， distribution and other aspects， so as to effectively prevent and control the occurrence foodborne diseases.

A double potential well flat ion trap was designed as an ion accumulating and focusing device for multi-reflection time-of-flight mass analyzer. Two potential wells of the trap were severally used for accumulation of injected ions, controlled cooling and ejection of trapped ions, which had features to accumulate ions continuously and cool ion for almost one period. While a flat ion trap with only one potential well is a traditional and excellent ion accumulating and focusing device, which has an intermittent ion accumulation and an ion cooling around half period. Compared with the single potential well flat ion trap, the double potential well flat ion trap had better performance on ion accumulation and focusing in principle. Four steps to run the trap were simulated and researched by an ion optics simulator of SIMION 8.1. The first step was ion accumulation, ions were successively injected into the trap, and then stored and accumulated in the first potential well. The second step was ion transfer, the trapped ions were transferred from the first potential well to the second potential well. The third step was ion cooling, the trapped ions were confined in the second potential well, and were simultaneously cooled by collisions with 0.5 Pa He. The fourth step was ion ejection, the trapped ions were ejected from the trap and focused into the next device. Ion optics simulations indicated that the trap had a period from 1 ms to above 10 ms, a total ion transmission efficiency of 83%, and an ion flux of at most 1.6×106 ions. In addition, ion packets ejected from the trap had thermalized with radial diameters of 1.0 and 1.0 mm, angular standard deviations of 24 mrad and 16 mrad, and an energy standard deviation of 15 eV. This trap can be coupled with and provide high-flux and full-focusing ion packets for multi-reflection time-of-flight mass analyzers, due to an excellent suitability between the operation of the analyzer and the period, the ion transmission efficiency, the ion flux, and ejected ion packets of the trap.

Analyses of representative accident scenarios are imperative to assess and evaluate the inherent safety features of a prismatic modular high temperature gascooled reactor (HTGR). The accident progression of a HTGR is typically characterized by the coupling of multiphysics phenomena. However, computational codes available for the HTGR accident analyses are still relatively rare at present, especially those dedicated to the prismatictype core design. In addition, many of these codes are either lumpedparameter that cannot give the detailed threedimension (3D) distributions of key variables (e.g. fuel temperature), or are incapable of capturing the coupling of major phenomena. As a consequence, a generic CFD code, i.e. COMSOL multiphysics, was employed in this work to create a detailed 3D geometry representing the reactor, including fuel assemblies containing fuel and coolant channels, graphite moderator blocks, side reflector as well as the reactor pressure vessel. Specifically, the passive residual heat removal system (RCCS) was simply treated as a convective boundary condition due to the lack of detailed design scheme right now. A point kinetics module was prepared in this work using C++ language to account for the transient neutron kinetics. The Gear algorithm was applied to numerically solve the system of equations of the point kinetics, given that the stiffness is relatively large. The C++ was then compiled into dynamic link library (DLL), which was accessed by the COMSOL simulation in the form of an external function, with the fuel and moderator temperatures evaluated by COMSOL as input arguments. The steady state under normal operation condition was first calculated, which served as the initial condition for the subsequent transient analyses for three selected typical accidents, including pressurized loss of forced cooling (PLOFC), PLOFC without scram (PLOFC+ATWS), and reactivity insertion without scram (RIA+ATWS) accidents. Finally, sensitivity analysis was carried out on the effect of radiative emissivity between reactor pressure wall and RCCS. The simulation results show that the peak fuel temperature throughout the whole accident progression is remained far below its upper limit value (1 620 ℃) with a considerably large margin, implying that the integrity of fuel assemblies can be successfully guaranteed under the accident scenarios concerned in the present work. Moreover, enhancement of the RCCS heat removal capacity can significantly relief the accident consequence for PLOFC accident but lead to an inverse trend for ATWS accident, which underlines the importance of further comprehensive analysis and modeling validation. To conclude, the computational model developed in this work along with the derived results can serve as the starting point for future development of the accident analysis tool, which is applicable for the incoming indepth safety analysis and assessment works.

ObjectiveTo understand the microbial contamination status of retail Chinese salads in Huzhou， and conduct a fast quantitative risk assessment to provide reference for foodborne disease prevention and control.MethodsIn 2019 and 2020， 461 samples of retail Chinese salads were randomly collected and detected for E.coli， Salmonella， Listeria monocytogenes， and B.cereus. According to the relevant standards， the status of microbial contamination was evaluated， and the health risk was preliminarily evaluated by sQMRA tool.ResultsThe unqualified rate of E.coli in retail Chinese salads was the highest （48.94%， 46/94）， and the average concentration was 104.34 CFU/g， which was mainly in the circulation links of farmer’s markets and online stores （P = 0.004）. The detection rates of Listeria monocytogenes， S.aureus， Salmonella and B.cereus were 9.54% （44/461）， 5.21% （24/461）， 1.30% （6/461） and 1.06% （1/94）， respectively. The unqualified rates of S.aureus（≥104 CFU/g） and B.cereus （≥105 CFU/g） were zero. The estimated annual incidence of four food borne pathogens was 2 208 cases， the estimated probability was 7.21 × 10-4， and the risk level was medium.ConclusionThe sanitary quality of retail Chinese salads in Huzhou City is not optimistic， E.coli contamination is the most serious. The contamination of four major food borne pathogens can lead to certain health risks. And further surveillance， assessment and management are needed．

Objective To summarize the key points of neuroendoscopic transcranial resection for cerebellopontine angle (CPA) tumors. Methods Twenty⁃eight patients with CPA tumors diagnosed and treated in Xiangya Hospital Central South University from January 2019 to December 2020 were included, and all of them underwent neuroendoscopic transcranial surgery to remove CPA tumors. Results All the 28 patients were successfully treated with neuroendoscopic transcranial resection of tumors in CPA region, and the tumors were totally removed. After operation, 9 cases of acoustic neuroma, 8 cases of meningioma, 9 cases of cholesteatoma, one case of hemangioblastoma, and one case of trigeminal neurinoma were confirmed by postoperative pathology. Postoperative facial nerve function was grade Ⅲ in 3 cases, grade Ⅱ in 6 cases, and grade Ⅰ in 19 cases. One patient had no obvious recovery of auditory nerve function injury, and 2 patients had dizziness, vertigo and nausea after operation. No complications such as cerebrospinal fluid leakage, meningitis and incision infection occurred, and no death occurred. At 3 months of follow ⁃ up, no tumor recurrence was seen on MRI, and no new neurological symptoms occurred. Conclusions Neuroendoscopic transcranial resection of CPA tumors has many advantages, but also has some shortcomings, and has a good development in the future.

Isothermal compression tests were carried out on a Gleeble-3500D thermal simulation machine. The hot compression deformation behavior of a new hot-extruded Ni-Co-Cr-based powder metallurgy(P/M) superalloy at the temperatures from 1020℃ to 1110℃ with the strain rates from 10-3 s-1 to 1 s-1was systematically investigated. The flow stress curves were corrected by friction. Using the friction-corrected data, the constitutive equation for hot compression of the alloy and the flow stress model considering the strain compensation were established, respectively. At the same time, the hot processing map was built, and the hot deformation parameters of the alloy were optimized by combining with the analysis of the microstructure. The results show that apparently dynamic recrystallization occurs in the process of hot compression of the alloy, and the flow stress decreases with the decrease of strain rate or the increase of deformation temperature. The predicted values obtained from the developed flow stress model considering the strain compensation agree well with the experimentally friction-corrected data. According to the hot processing map and microstructural analysis, the reasonable hot working parameters of the alloy were suggested to be at the deformation temperatures of about 1076-1103℃ and the strain rates of about 10-3-10-2.77s-1.

Aimed at the great metallographic structure differences between every part of the large-scale thin-wall complex integral precise titanium alloy casting, a non-destructive evaluation method based on metallographic structure statistical analysis is proposed. Under the non-destructive condition, the casting skin structure information is given by means of handheld microscope. The casting skin structure statistic model is established. And the result of integral casting structure is given. Through comparative analysis between non-destructive evaluation (Method A) and metallography detection of the dissect sample (Method B), the results show that the non-destructive evaluation evaluates the metallographic structure effectively. The mean value and half-width of the grain size distribution curves fit the characteristic of Gaussian distribution. And the grain size mean value in both two methods increase linearly along with the casting thickness, and the slope deviation is within the limits of 6%; the half-width relative deviation increases exponentially along with the casting thickness, approached 26%.

Progresses have been made in the development of digitalized and miniaturized rubidium atomic frequency standard (RAFS). In the traditional RAFS circuits, the 6 840 MHz microwave signal is mixed with the 5.312 5 MHz signal generated by the frequency synthesizer to obtain 6 834.687 5 MHz microwave signal, which is used to excite rubidium atom transition. Early RAFS frequency synthesizer used a large number of discrete analog devices, and showed disadvantages such as low degree of digitization, complicated parameter optimization and large physical size. The direct digital synthesizer (DDS) scheme used currently generates the 5.312 5 MHz signal directly, but often needs to multiply the 10 MHz signal. It has the disadvantages of low spectral purity and high phase noise. This paper introduces a digital frequency synthesizer solution that generates the 5.312 5 MHz signal. The design eliminates the need for a 10 MHz multiplier circuit when using a DDS device. It has the advantages of high spectral purity, low phase noise and adjustable output frequency/phase.

As-cast microstructures and phase compositions of Mg-3.52Sn-xM and Mg-6.54Sn-xM (M=Al, Zn, Nd, Gd) alloys were investigated by optical microscope, scanning electron microscope and X-ray diffraction. Meanwhile, the tensile mechanical properties were tested. The results show that the coarse dendrite is refined slightly and few block Mg2Sn phase still exists when 0.91% (mass fraction, the same below) Al and 1.03%Zn are added into Mg-3.52Sn alloy, respectively. When 0.92%Nd and 1.10%Gd are added respectively, the dendrite weakens obviously and many small block or fine short rod-shaped compounds Mg-Sn-Nd and Mg-Sn-Gd can be observed. When 0.93%Al and 1.08%Zn are added into Mg-6.54Sn respectively, the dendrite is refined obviously and Mg2Sn phase tending to precipitate in the state of continuous net begins to break slightly. When 0.86%Nd and 0.74%Gd are added respectively, the dendrite weakens significantly and Mg2Sn phase has already broken into small block completely or significantly. Meanwhile, many small block or fine short rod-shaped compounds Mg-Sn-Nd and Mg-Sn-Gd can also be observed. The respective addition of about 1%Al and Zn into the Mg-3.52Sn and Mg-6.54Sn binary alloys respectively can enhance the tensile mechanical properties namely the ambient and elevated temperatures effectively, while the respective addition of about 1%Nd and Gd cannot enhance them effectively, especially for the addition of Nd.

Objective To explore the efficacy and advantages of intracranial-intracranial bypass for the treatment of complex intracranial aneurysms. Methods A total of 9 patients with complex intracranial aneurysms who underwent intracranial-intracranial bypass in Xiangya Hospital of Central South University from February 2014 to May 2020 were included, and were treated with grafts bypass or reimplantation of recipient arteries. All cases underwent CTA or DSA to detect the patent of grafts, whether aneurysms were completely clipped or resected and aneurysms recurrence occurred during the follow-up. Modified Rankin Scale (mRS) was used to evaluate the neurological prognosis at discharge and during the follow - up. Results Radial artery (RA) or great saphenous vein (GSV) was used for interposition in 4 cases, and recipient arteries were used for reimplantation in 5 cases. Of 4 cases of interposition, the cavernous sinus seoment of internal carotid artery (ICA)-GSV-ICA bypass was adopted in one case, middle cerebral artery (MCA) M2-RA-M2 bypass in one case, anterior cerebral artery (ACA) A3-GSV-A3 bypass in one case, posterior cerebral artery (PCA) P2 - RA - P2 bypass in one case. Of 5 cases of reimplantation, MCA M2 inferior trunk was reimplanted to M2 superior trunk in one case, ACA A3 was reimplanted to contralateral A3 in 2 cases, the posterior inferior cerebellar artery (PICA) was reimplanted to the anterior inferior cerebellar artery (AICA) in 2 cases. CTA in 3 d postoperatively showed all cases grafts were patent and aneurysms disappeared. After 3 months of discharge, 2 were lost to follow-up. The other 7 cases kept the patency of grafts and no new aneurysms, and were constantly followed up, with an average follow-up time of 30.71 months, and mRS score was 1 or lower. Conclusions Intracranial-intracranial bypass can be applied for complex intracranial aneurysms that are difficult for conventional surgical treatment to solve. Compared with extracranial - intracranial bypass, its grafts are shorter and its hemodynamics features are more in line with physiological conditions. [ABSTRACT FROM AUTHOR]

Objective To analyze the genetic evolution and molecular characteristics of the H5N6 avian influenza virus A/Changsha/1/2022(H5N6) in a human infection case in Changsha City, providing insights for the prevention and control of H5N6 avian influenza transmission to humans. Methods The sample underwent whole-genome sequencing on a third-generation sequencing platform. Reference sequences were downloaded from the NCBI and GISAID databases for comparison. The phylogenetic tree was constructed and key amino acid mutation sites were analyzed using MEGA7 software. Results The sequence analysis results revealed that the strain studied belongs to the H5 subtype Clade 2.3.4.4b branch. The PB1 gene shared 99.69% homology with the H5N6 virus A/duck/Hunan/S40199/2021(H5N6) from Hunan Province; PB2 had 98.58% homology with A/Whooper swan/Sanmenxia/Y36/2020(H5N8); and other sequences showed high homology with the strain A/Guangdong/1/2021(H5N6) discovered in Guangzhou in 2021. These results indicate that an infection with a recombinant H5N6 subtype avian influenza virus caused the case. The amino acid composition of the cleavage site was RERRRKR ↓GLF, consistent with high-pathogenicity avian influenza characteristics. The HA sequence showed no mutations at the Q226L and G228S sites, indicating the preservation of characteristics binding to avian receptors. However, mutations at the S127P, S137A, T160A, T192R, and A267T sites increased the virus's affinity for humans. A deletion found in positions 59-70 of the NA protein stalk implies enhanced viral virulence in mammals. Mutations were noted in the internal genes; S622G in PB1, K389R and V598T in PB2, N409S in PA, N30D and T215A in M1, and P42S in NS1, which may enhance the virulence of avian influenza virus in infecting mice. Conclusions The H5N6 virus strain detected in a human case in Changsha City in this study is highly pathogenic, prone to bind to avian receptors, but numerous mutations at key amino acid sites facilitate infection in humans. Continuous monitoring and research on H5N6 avian influenza virus should be strengthened [ABSTRACT FROM AUTHOR]

Plastics were invented a century ago and utilized by human being ever since, which bring tremendous convenience to our daily life. Plastic products and constituents can break down into microplastics (MPs) while undergoing combined physical, chemical, and biological processes. MPs in the environments might enter into the drinking water. Such contamination and potential health risks gradually become concerns. The qualitative and quantitative detection of MPs is still in its developmental stage. Raman spectroscopy (RS) is one of the commonly used sensitive, non-invasive and non-destructive optical methods in MPs analysis. This article primarily focuses on the sources, potential hazards of MPs in drinking water, and research advancements in RS technology, in order to promote better understanding of MPs contamination and drawattention to the research and development of MPs detection technology. [ABSTRACT FROM AUTHOR]

Etomidate (ET) is widely used as an anesthetic in clinical practice. The long-term use of ET can lead to negative effects, such as decreased consciousness and cognitive impairment. However, the developmental neurotoxicity of ET on fish remains unclear. To address this issue, zebrafish embryos were exposed to ET from 2 hpf (hours post-fertilization) to 168 hpf at 0. 010, 0. 091, 0. 501, 9. 400, 84. 31 and 664. 4 μg·L-1. The physiological development, behavior and cell apoptosis, and transcriptional expression of genes related to dopamine (DA) and γ-aminobutyric acid (GABA) pathway were detected to investigate the developmental neurotoxicity of ET. The results showed that 664.4 μg·L-1 ET decreased hatching rate at 48 hpf and 60 hpf. 0.091 μg·L-1 and 0.501 μg· L-1 ET decreased body length in larvae at 168 hpf. At 48 hpf, 0.010, 0.091, 0.501, 9.400, 84.31 and 664.4 μg·L-1 ET increased malformation. 0.501, 9.400, 84.31 and 664.4 μg·L-1 ET increased malformation at 96 hpf. Additionally, 0.501, 9.400 and 664.4 μg·L-1 ET increased malformation at 168 hpf. The 0.010 μg·L-1 ET caused cell apoptosis in the brain, while 664.4 μg·L-1 ET inhibited apoptosis. In addition, behavior analysis indicated that ET inhibited touch behavior at all concentrations. The 0.091 μg·L-1 ET enhanced swimming behavior in zebrafish larvae, while 664.4 μg·L-1 ET weakened swimming behavior. ET increased anxious behavior in a concentration-dependent manner. The qPCR data showed that ET up-regulated the transcriptions of genes related to DA and GABA pathway at low concentration, while ET down-regulated the transcriptions of these genes at high concentration. The above results indicate that ET has significant neurodevelopmental toxicity in early development of zebrafish. [ABSTRACT FROM AUTHOR]

In recent years, due to the frequent occurrence of extreme weather, low temperatures (LT) became one of the main disasters restricting wheat production. LT has negative effects on wheat growth and yield formation, especially at booting stage. Exogenous spraying of 6-benzylamino adenine (6-BA) after LT at booting stage can alleviate the damage caused by LT in wheat, but the related molecular regulation mechanism is still unclear. In this study, transcriptome sequencing technology was used to analyze the molecular mechanism of 6-BA improving cold tolerance in wheat. The LT sensitive variety Wanmai 52 and insensitive variety Yannong 19 were selected as the experimental materials. The experiment was carried out in combination of potted and field planting. Two wheat cultivars were planted in plastic pots at a planting density of ten plants per pot. At booting stage, the pots were moved into an artificial climate chamber for low temperature treatment. At the end of the treatment, 20 mg L-1 6-BA solution was sprayed, and an equal volume of distilled water was sprayed as the control. The morphology of young spike, and the content of soluble sugar and starch in young spikes were determined. Some candidate differentially expressed genes (DEGs) were screened and their relative expression patterns were analyzed by qRT-PCR, and the results were verified by qRT-PCR. After 10 days, compared with the control, the morphological development of young spike was better, fuller and longer. The contents of soluble sugar and starch in young spikes increased after 6-BA treatment. The results showed that 22,770 DEGs were identified in Wanmai 52 and 9866 in Yannong 19, respectively, and 661 genes were up-regulated in the two cultivars. ARF5, AGPL1, 1-SST, SWEET15, and other genes were screened out, which were related to the regulation of plant hormone level, starch synthesis, and sugar metabolism. GO and KEGG enrichment analysis were performed on the selected differential genes. GO annotation revealed that the functions of the differential genes of the two varieties were mainly concentrated in cell structure stability, metabolism, and catalytic activity. KEGG enrichment analysis demonstrated that signal transduction, regulation of endogenous hormone levels, carbon metabolism, the changes of membrane structure and function had significant changes. In conclusion, 6-BA could alleviate cold damage by regulating the metabolism of antioxidant substances, hormone signal transduction, carbohydrate metabolism, osmotic adjustment, and other ways in wheat. The results provide a theoretical basis for exploring the cultivation measures to reduce the damage of low temperature on wheat in spring. [ABSTRACT FROM AUTHOR]

Objective To analyze the routine test parameter levels of patients with colorectal adenoma and colorectal cancer, and develop a prediction model. Methods A total of 580 patients diagnosed with colorectal adenoma (117 patients) and colorectal cancer (463 patients) were included in the retrospective study. The patients were randomly divided into two groups according to a 7:3 ratio: a training set with 406 cases and a validation set with 174 cases. Logistic regression analysis was used to establish a prediction model, and a nomogram was drawn. The model′s discrimination, calibration, and clinical applicability were evaluated using receiver operating characteristic curve (ROC), calibration plot, and decision curve analysis (DCA). Results Univariate logistic regression analysis identified 13 potential predictors: age, fecal occult blood test (FOBT), fibrinogen (FIB), thrombin time (TT), albumin (ALB), white blood cell value (WBC), neutrophil count (NEUT#), hematocrit value (HCT), mean corpuscular hemoglobin (MCH), red cell distribution width (RDW), platelet count (PLT), mean platelet volume (MPV), and activated partial thromboplastin time (APTT). Multivariate logistic regression analysis showed MPV, FIB, ALB, FOBT, TT, and HCT were risk factors for colorectal cancer in patients with colorectal adenoma (P

The travel efficiency of public transportation is a key indicator for judging whether the quality of public transportation has developed compared with other modes of transportation, especially private vehicles. The quality of public transportation is also an important reference factor for residents' choices. With the rapid urban expansion and improvement in motorized travel levels, reducing the time difference between private vehicles and public transportation is the key to improving the attractiveness of public transportation. The relative spatiotemporal efficiency is based on the time difference between private vehicles and public transportation, considering the number of passengers. Recently, scholars have shown great interest in relative travel efficiency. However, relevant studies have shown poor real-time performance because of the unavailability of large datasets, which cannot dynamically reflect the characteristics of relative travel efficiency. The spread of big data and internet maps enables us to perform systematic efficiency evaluations. The internet map incorporates various travel-related information such as travel route, time, and cost under different travel modes based on real-time road conditions and provides access to the extracted embedded travel information. This study proposes a framework for evaluating the spatiotemporal efficiency of different travel modes based on real-time road conditions in Shenzhen. First, travel time data were obtained using an internet map during the morning, afternoon, and evening rush hours. The passenger flow volume was computed using smart card data. We then constructed an evaluation index model of spatiotemporal efficiency based on the relative time efficiency and weighted passenger flow volume. Finally, the results highlighted the following: 1) the relative time efficiency of public transportation was higher during the evening rush hours than in the morning. The main reason was the increase in private vehicle travel time during the evening rush hours, reflecting the complexity of urban road conditions during the evening; 2) the spatiotemporal efficiency index of central public transport stations fluctuated greatly during the three periods, which was closely related to the dynamics of traffic volume caused by the high concentration of workplaces; 3) the spatiotemporal efficiency index of public transportation stations exhibited spatial aggregation characteristics in the three periods, highlighting the different clustering characteristics in the central and outer areas; 4) the spatiotemporal efficiency index of subway stations was generally higher than that of bus stations, reflecting the importance of subway systems in urban transportation networks. Evaluating the relative travel efficiency of urban public transport contributes to analyzing the development status of public transportation, supporting decisions to achieve high-quality development of public transport, and providing travel information for the government and residents.

Objective. To analyze the correlation between salivary microbiome and host blood lipid levels. Methods. Samples of saliva from 114 volunteers aged 45-60 years were collected to extract total DNA, and then 16S rDNA V3-V4 region was amplified with polymerase chain reaction. After the amplified products were sequenced via Illumina MiSeq PE300 platform,the obtained sequences were subjected to operational taxonomic units (OTUs) clustering and species annotation.The Spearman correlation analysis was also carried out to find the correlations between the top 50 abundant genera in the salivary microbiome and host blood lipid levels, P<0.05 was considered as statistically significant difference. Results. The saliva samples of 114 volunteers were sequenced with an average sequence number of 41 084± 740, and the number of OTUs obtained by clustering was 1 153, annotated to 23 phyla, 43 classes, 89 orders, 147 families and 317 genera. Species clustering heat map of 114 samples suggested that salivary microbiome has similar abundance patterns of species composition in the population.Spearman correlation analysis showed that among triacylglycerol (TAG) the top 50 abundant genera in the salivary microbiome, Neisseria spp. were negatively correlated with the host serum total cholesterol (TCH), and low density lipoprotein cholesterol level (LDL-Ch); Gemella spp. are positively correlated with Host serum TCH and LDL-Ch; high-density lipoprotein cholesterol presents negative correlation with Comamonas spp., Filifactor spp. and Parvimonas spp. Conclusions. The composition structure of salivary microbiota in the population is quite stable and is related to the levels of host blood lipids. It is promising to further explore salivary microbiota as early warning indicators of individual lipid metabolism abnormalities. [ABSTRACT FROM AUTHOR]

Electrocorticogram(EEG) can reveal people's psychological activities correctly, so EEG is widely used in psychological test. In this paper, a method based on the nonlinear feature fusion of EEG signals for concealing behavior recognition in the psychological test is presented. First, after pre-processing the EEG signals of the subject obtained in the psychological test, four nonlinear features, including Lempel-Ziv Complexity(LZC), Sample Entropy(SE), Permutation Entropy(PE) and Fuzzy Entropy(FE), are extracted. Then, the fusion and dimensionality reduction of the features by Multidimensional Scaling(MDS) is done. Finally, the Regularization Kernel Extreme Learning Machine(RKELM) is applied to construct the classifier and the performance of the four trained classifiers is verified by the test set. The experimental results show that the accuracy of the proposed system is 82.9%, which indicate the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

In view of the fact that wet-cloth facial masks are complicated in components and low in utilization efficiency of active ingredients, an all-solid-state nanofiber facial mask was innovatively developed. In the paper, brief introductions were given to the formation mechanism, microstructure and structural features of the nanofiber facial mask. High-molecular polymer and active ingredients were directly turned into nano cellosilk and a piece of nanofiber membrane of micrometer thick was span onto the receiving base cloth. Compared with common wet-cloth facial mask, nanofiber facial mask has less additive ingredients but works more effectively. For example, it is easy to apply, good at water retention, excellent in loading capacity and biocompatibility. The paper ended with existing problems with materials of all-solid-state nanofiber facial mask, its development orientation and application prospect. [ABSTRACT FROM AUTHOR]

Objective To investigate the clinical efficacy and prognostic factors of autologous hematopoietic stem cell transplantation (ASCT) for Hodgkin's lymphoma (HL). Methods We retrospectively analyzed the data of 38 patients with HL who underwent ASCT. Kaplan-Meier and Cox methods were used to analyze the curative effect and prognostic factors after transplantation. Results All 38 transplanted patients obtained hematopoietic reconstitution. The CR rates before and after transplantation were 55.3% and 81.6%, respectively, and the 5-year PFS and OS were 76.1% and 79.0%, respectively. Univariate analysis showed that B symptoms, IPS score, pre-transplant remission status, extranodal invasion, and pretreatment regimen were the factors affecting the prognosis of ASCT in patients with HL. Multivariate analysis showed that B symptom was an independent risk factor affecting 5-year PFS. Conclusion ASCT is effective in the treatment of high-risk, relapsed, and refractory patients with HL. B symptom is an independent risk factor affecting the prognosis of transplantation.

Natural graphite is a new-technology mineral resource led by new mineral preparation and application technologies and an important raw material that supports the development of China’s strategic emerging industries. This paper analyzes the demand for high-quality development of graphite resources and the graphite material industry, summarizes the development status, unveiled development potentials and major challenges, and puts forward goals for next stage development. Furthermore, this paper proposes the following measures: (1) establishing a technology innovation system that focuses on the deep processing of graphite; (2) optimizing the allocation of resources and boosting the development of green graphite plants and mines; (3) strengthening the capacities of platforms to consolidate the technological innovation foundation for industrial and supply chains; and (4) focusing on breakthroughs in the xclusive application of graphene’s uniqu physical properties and avoiding excessive marketing. Additionally, it is necessary to set up a sophisticate database that covers the entire industrial and supply chains of graphite, establish a long-term policy mechanism that supports the high-quality development of China’s graphite industry, accelerate resource integration to construct an international graphite valley, and improve innovation platforms to enhance talent trainning.

On the basis of fully understanding the scientific connotation of coordinated development of urban agglomeration in the Guangdong-Hong Kong-Macao Greater Bay Area, the evaluation index system of coordinated development is constructed from four dimensions: industrial coordinative innovation, environmental coordinative governance, service coordinative sharing and institutional coordinative arrangement. The theory and method of space of flows, big data, network analysis and interlocking network model are comprehensively used to quantitatively analyze the interurban relationship, liquidity, connectivity and boundary effect. The research shows that: 1) Interurban capital flow is concentrated between Guangzhou and Shenzhen, and interurban knowledge flow is concentrated among Hong Kong, Guangzhou and Shenzhen. Macao, Zhuhai, Zhongshan and Jiangmen have higher level of collaborative environmental governance, while Shenzhen-Dongguan-Huizhou and Guangzhou-Foshan have lower level of collaborative environmental governance. The interurban service coordination sharing level of infrastructure such as transportation, communications, logistics and banking is higher among cities of Guangzhou-Shenzhen, Guangzhou-Foshan and Shenzhen-Dongguan. And Hong Kong and Macao have institutional advantages in cross-border regional coordination. 2) Guangzhou and Shenzhen, Guangzhou and Foshan, Shenzhen and Dongguan, and Hong Kong and Shenzhen have the best level of coordinated development in the Guangdong-Hong Kong-Macao Greater Bay Area. At the same time, Guangzhou and Dongguan, Shenzhen and Foshan show a linkage trend. Although the de-boundary trend is obvious and the interurban liquidity is enhanced, the coordinated development level of the Guangdong-Hong Kong-Macao Greater Bay Area is generally not high. 3) The collaborative capacity of Guangzhou and Shenzhen is the strongest, and there is still much room for improvement in the collaborative capacity of the two international cities, Hong Kong and Macao. It is of great practical value to deeply understand the typical characteristics and potential trends of the coordinated development of urban agglomeration in the Guangdong-Hong Kong-Macao Greater Bay Area for the construction of international first-class bay area and world-class urban agglomeration.

To investigate the differences of soil carbon, nitrogen, and carbon stable isotopes in Zoige wetland, we analyzed the abundance of carbon stable isotopes and the contents of carbon and nitrogen in soils of three kinds of retrogressive successional grasslands (swampy meadow, steppe meadow, and degraded meadow). The results showed that the S13C values in the meadow soil of Zoige alpine wetland ranged from -26.21‰ to -24.72‰. The abundance of δ13C increased with the depth of soil. There was a significantly negative relationship between δ13C values and logarithm of soil organic carbon content across the soil profile. The δ13C values in the surface soil (0-10 cm) followed the order of grassland meadow > degraded meadow > swampy meadow, and the values followed the order of grassland meadow > swampy meadow > degraded meadow. Soil organic carbon content was 105.32, 42.11 and 31.12 g ⋅ kg-1, while nitrogen content was 8.74, 3.41 and 2.81 g ⋅ kg-1, and C/N was 11.26, 11.23 and 10.89, in the swampy meadow, grassland meadow and degraded meadow, respectively. The soil C/N was lower in degraded meadow than that in swampy meadow and grassland meadow. The total organic carbon and nitrogen content decreased obviously with increasing soil depth. The variations of soil δ13C among meadows with different degradation stages were mainly restricted to the 0-10 cm soil layer. The β values and C/N were the lowest in degraded meadow among three stages, suggesting that the mineralization rate of degraded meadow soil organic matter was relatively fast. [ABSTRACT FROM AUTHOR]

In this paper， the types and expression characteristics of microRNAs related to cognitive impairment in schizophrenia patients were reviewed， so as to provide a reference for further research on the characteristics of cognitive impairment in schizophrenia patients， and to open up new ideas for further research on the molecular mechanism of cognitive impairment as well as subsequent precise treatment and prognosis evaluation.

In order to make gob-side filling body of gob-side entry retaining adapt to the roof movement, the properties of concrete material is modified by adding polymer and steel fiber to achieve the purpose of “yield-support”. The test of modified concrete was carried out to test the uniaxial compressive strength under different ratios, and the best ratio of each component was determined. The stress of filling body and displacement of upper and lower plate are simulated by FLAC3D numerical simulation method to analyze yielding performance. The results show that the ethylene vinyl acetate copolymer（ＥＶＡ） improves the plastic deformation ability of the concrete material, and steel fiber has a good effect on the ductility of concrete. When the dosage of polymer is 15%, the yielding property is 6.10%. The results of numerical simulation show that the modified concrete of gob-side filling material can sink with roof and release the pressure of the roof movement under the condition of its own strength, and finally achieve the purpose of coordination and yield. In addition, the best width of filling body beside gob-side retaining entry is 1.2 m.

Aβ-Amyloid positron imaging agent 18F-AV45 was synthesized automatically using TRACERlab FX2 N radiosynthesis module and the clinical imaging of 18F-AV45 was evaluated. AV105 was used as the precursor, which reacted with 18F ion at 130 ℃ for 10 minutes on the TRACERlab FX2 N, followed by acid hydrolysis and neutralization with NaOH, and then the reaction mixture was separated by high-performance liquid chromatography (HPLC) method to obtain the target compound 18F-AV45, which was next purified by solid-phase extraction method. The HPLC quality control analysis of the final 18F-AV45 injection was carried out. The radiochemical purity of 18F-AV45 was determined using a HPLC system equipped with a C18 column (InfinityLab Poroshell 120 EC-C1, 4 μm, 4.6 mm×100 mm) which was eluted with a mobile phase of acetonitrile/20 mM ammonium acetate (40∶60, v/v) at a flow rate of 1 mL/min. The absorbance of 350 nm and the radioactivity in the eluate flow were monitored with a diode array detector and a flow count detector, respectively. One case of patients with Alzheimer’s disease (AD) and one healthy person underwent 18F-AV45 PET/CT scanning. The results showed that it took 80 minutes from 18F ion to 18F-AV45, no-corrected efficiency was (17.02±1.52)%(n=6), radiochemistry purity was over 95%. The results of PET imaging showed that 18F-AV45 uptake was diffusely increased in the cerebral cortex of patient with AD, which indicated deposition of amyloid beta protein in cerebral cortex. And the results of imaging of the healthy person showed 18F-AV45 was no obvious uptake in cerebral cortex, namely, there was no deposition of amyloid beta protein in cerebral cortex. 18F-AV45 could be synthesized automatically and simply by TRACERlab FX2 N with good repeatability. The quality of 18F-AV45 injection meets the requirements for clinical use. In addition, 18F-AV45 has clinical application value in the diagnosis of patients with AD.

The laminate is essentially bonded together to form the individual laminate by the matrix, any delamination of the laminate must be initiated from a matrix failure. Based on this viewpoint, the initiation of laminate delamination was predicted through analyzing the stresses of the matrix. A three-dimensional finite element method is used to calculate the stress field of a symmetrically laminated plate under an axial load. A convergence study was performed and an average stress method was proposed to solve the singularity problem. Then the internal stresses in the fiber and matrix were determined in terms of the bridging micromechanics model. Finally, a Mohr criterion was used to detect the failure of matrix. T800/914 angle-plied laminates were considered. The results show that this approach is able to correlate reasonably with the available experimental data.

In order to predict the strength of a composite only based on the mechanical properties of its constituent fiber and matrix materials measured independently, 3 challenging problems must be resolved with high success rate. First, internal stresses in the fiber and matrix must be accurately evaluated. Second, efficient failure detection of the composite in terms of the internal stresses, i.e., the micromechanical strength theory, must be achieved. Last but not the least, the input data of in-situ strengths of the matrix, which can hardly be measured through experiments, must be correctly determined according to its original counterparts available independently. Each of these problems is by no means easy to deal with. This is why the prediction of composite strength is extremely difficult. The bridging model, originally established by HUANG Zheng-ming and further developed to a powerful theory, presents a systematic approach towards solving all of the 3 problems. This paper briefly summarizes the theory by focusing on some of the latest advancements. A number of further research topics are also highlighted. [ABSTRACT FROM AUTHOR]

In order to effectively monitor the damage and stability extent of coal rock roadway, conduct the studies of coalrock damage and failure characteristics in Zhangcun Coal Mine. Firstly, the mechanics parameters of coal rock measured through the uniaxial compression experiment in Zhangcun Coal Mine, then obtained the mesomechanics parameters of coal rock and experiments carried out under different confining pressures by particle flow code. Analyzing the acoustic emission and strain energy characteristics in the failure process of coal rock, and consequently revealed the coal rock failure mechanism through the generation, propagation and coalescence process of cracks. Some main research results are as follows; the maximum intensity of acoustic emission lags behind the peak stress, the lag is sensitive with confining pressure in lower confining pressure range, the effect is attenuated in higher range. Arise the significant quiet period of acoustic emission before the maximum intensity of acoustic emission with confining pressure increasing, and point out the quiet period caused by the strain energy absorption in the process of the generation of serious damage zone and damage healing. Coal rock failure process is divided into four stages; damage random dispersion, damage coalescence in local scope, fissure steady developing into local crack, crack extension bring about coal rock failure. Analyzing the effect of confining pressure on the four stages. [ABSTRACT FROM AUTHOR]

LED is a trend of development and application of the light source in future, the design of LED drive is a new technology in lighting field. The main function of LED driver in a certain condition, no matter the input and output voltages change, can stabilize the current flowing through the LED. Characteristics of LED and its driving device, from theory to design, are deeply discussed. The design uses double supply, dual output charge mode, and consists of embedded computer control module, control of the constant current source circuit with large power triode as the core. Dual power supply of the original intelligent contactless electronic switching power supply automatically, system can also be used for battery power detection and automatic charging. This design was also tested by STC (The Hongkong standards and Testing Center), about the ultimate of magnetic radiation leakage, the data show that the design is successful. [ABSTRACT FROM AUTHOR]