城市更新中儿童友好的学径人性化设计策略研究

儿童友好的学径是儿童友好型城市建设中必不可少的一环,在开展儿童友好空间建设和改造时,应更加重视儿童参与、倾听儿童诉求、保障儿童权益。通过对学校周边道路交通特征的分析,提出儿童友好型学径人性化改善策略,希望以此助推儿童友好的学径人性化设计,促进儿童友好的学径的建设。

儿童友好理念下的城市学径空间设计研究

城市化并不一定能为儿童带来可持续的城市空间,而通过规划儿童友好理念下的城市空间不仅有助于儿童成长,还能使城市家园变得更加繁荣。伴随着我国从国家层面、多省市出台的一系列儿童友好城市建设举措,如何营建一个适儿化的城市空间成为了一个亟待解决的问题。文章首先根据国际与我国儿童友好城市建设的经验与政策,提出安全性、连续性、趣味性、包容性与亲自然性的城市学径空间设计原则。其次,根据我国现阶段儿童友好型城市的行动实践,提出城市学径空间设计的思路。以期为儿童友好理念下的城市建设提供参考,促进儿童安全、健康、快乐地成长。

Characterization of the dissociation pathways of dichloromethane and glutathione in dichloromethane dehalogenase

Dichloromethane(DCM)dehalogenase stands as a crucial enzyme implicated in the degradation of methylene chloride across diverse environmental and biological contexts.However,the unbinding pathways of ligands from DCM dehalogenase remain unexplored.In order to gain a deeper understanding of the binding sites and dissociation pathways of dichloromethane(DCM)and glutathione(GSH)from the DCM dehalogenase,random accelerated molecular dynamics(RAMD)simulations were performed,in which DCM and GSH were forced to leave the active site.The protein structure was predicted using Alphafold2,and the conformations of GSH and DCM in the binding pocket were predicted by docking.A long equilibrium simulation was conducted to validate the structure of the complex.The results show that GSH is most commonly observed in three main pathways,one of which is more important than the other two.In addition,DCM was observed to escape along a unique pathway.The key residues and protein helices of each pathway were identified.The results can provide a theoretical foundation for the subsequent dissociation mechanism of DCM dehalogenase.

Molecular Dynamics Study on Microstructure of Potassium Dihydrogen Phosphates Solution

Molecular dynamics simulations were carried out to study the internal energy and microstructure of potassium dihydrogen phosphates （KDP） solution at different temperatures. The water molecule was treated as a simple-point-charge model, while a seven-site model for the dihydrogen phosphate ion was adopted. The internal energy functions and the radial distribution functions of the solution were studied in detail. An unusually large local particle number density fluctuation was observed in the system at saturation temperature. It has been found that the specific heat of oversaturated solution is higher than that of unsaturated solution, which indicates the solution experiences a crystallization process below saturation temperature. The radial distribution function between the oxygen atom of water and the hydrogen atom of the dihydrogen phosphate ion shows a very strong hydrogen bond structure. There are strong interactions between potassium cation and oxygen atom of dihydrogen phosphate ion in KDP solution, and much more ion pairs were formed in saturated solution.

Analysis of mechanical performance of braided esophageal stent structure and its wires

This paper aims to find the relationship between the structural parameters and the radial stiffness of the braided stent and to understand the stress distribution law of the wires. According to the equation of the space spiral curve, a three-dimensional parametrical geometrical model is constructed. The finite element model is built by using the beam-beam contact elements and 3D beam elements. The constituent nitinol wires are assumed to be linear elastic material. The finite element analysis figures out that the radial stiffness of the stent and the stress distribution of the wires are influenced by all the structural parameters. The helix pitch of the wires is the most important factor. Under the condition of the same load and other structural parameters remaining unchanged, when the number of wires is 24, the stress of the wire crosssection is at the minimum. A comparison between the vitro experimental results and the analytical results is conducted, and the data is consistent, which proves that the current finite element model can be used to appropriately predict the mechanical performance of the braided esophageal stents.

Molecular Dynamic Simulation of Melting Points of Trans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD） with Some Propellants

Molecular dynamic simulation was employed to predict the melting points Tm of TNAD/HMX, TNAD/RDX, TNAD/DINA, and TNAD/DNP systems （tans-1,4,5,8- tetranitro-1,4,5,8-tetraazadacalin （TNAD）, dinitropiperazine （DNP）, cyclotetramethylenetetranitroamine （HMX）, cyclotrimethylenetrinitramine （RDX）, and N-nitrodihydroxyethylaminedinitrate （DINA））. Tm was determined from the inflexion point on the curve of mean specific volume vs. temperature. The result shows that the Tm values of TNAD/HMX, TNAD/RDX, and TNAD/DINA systems are 500, 536, and 488 K, respectively. The TNAD/DNP system has no obvious Tm value, which shows the system is insoluble. Using Tm, the solubility of the four systems was analyzed. The radial distribution functions of the four systems were analyzed and the main intermolecular forces between TNAD and other energetic components are short-range interactions. The better the solubility is, the stronger the intermoleenlar interaction is. In addition, the force field energy at different temperature was also analyzed to predict Tm of the four systems.

Research on the Correlation between Meteorological Factors and Flue-cured Tobacco Chemical Components in Different Altitudes of Lincang Region

In this study, the relationship between major meteorological factors and tobacco chemical components in different altitudes of Yongde County, Lincang Region of Yunnan Province was studied using correlation analysis and path analysis methods.The results showed that there was a difference on meteorological factors in different altitudes, causing different impacts on chemical components of flue-cured tobacco; contents of nicotine and total nitrogen decreased with the rising of altitude, conversely, total sugar and reducing sugar contents increased with the rising trend of altitude, and the differences on the contents of potassium （K） and chlorine（CI）, and the ratio of K to CI in different altitudes were not significant, at the altitude of 1 250-1 450 m, each chemical component indicator was better. The correlation between main meteorological factors and conventional chemical components of tobacco leaves was as follows： contents of reducing sugar and total sugar increased with the increase of rainfall and relative humidity, and decreased with the increase of sunshine duration; nicotine content increased with the increase of accumulated temperature and sunshine duration; total nitrogen （N） content increased with the increase of daily mean temperature and accumulated temperature; sugar-alkali ratio increased with the increase of rainfall. Path analysis showed that the direct effect of sunshine duration on reducing sugar and total sugar of tobacco leaves was faint, but the indirect effect was obvious; meanwhile, the direct and indirect effects of it on nicotine and total N were the greatest.

Successful application of optimized aperture based CRS stack in the Shengli exploration area

The common reflection surface （CRS） stack is based on the local dip of the reflector and the reflection response within the first Fresnel zone. During the CRS stack all the information given by a multi-coverage reflection dataset can be successfully utilized. By now, it is known as the best zero-offset （ZO） imaging method. In this paper high quality CRS kinematic parameter sections are obtained by a modified CRS optimization strategy. Then stack apertures are calculated using the parameter sections which finally results in the realization of the CRS stack based on optimized aperture. Thus the advantages of CRS parameters are fully developed. Application to model and real seismic data reveals that, compared with the image section by a conventional CRS stack, the image section by CRS stack based on an optimized aperture improves both the signal-to-noise ratio and the continuity of reflection events.

Insight into Capture of Greenhouse Gas （CO2） based on Guanidinium Ionic Liquids

Quantum mechanics and molecular dynamics are used to simulate guanidinium ionic liquids. Results show that the stronger interaction exists between guanidine cation and chlorine anion with interaction energy about 109.216 kcal/mol. There are two types of spatial distribution for the title system： middle and top. Middle mode is a more stable conformation according to energy and geometric distribution. It is also verified by radial distribution function. The continuous increase of carbon dioxide （CO2） does not affect the structure of ionic liquids, but CO2 molecules are always captured by the cavity of ionic liquids.

Hydrodynamics and Lateral Gas Dispersion in a High-Density Circulating Fluidized Bed Reactor with Bluff Internals

Effect of bluff internals on the hydrodynamics and lateral gas mixing was studied in a 0.186m ID high-density riser. With the bluff internals, the extremely non-uniform radial profiles of solid fraction and particle velocity become flat and the dense downflow layer near the wall disappears, indicating the significant enhancement of solid turbulence introduced by the internals. The fluctuation velocity and solid fraction transient signal analysis indicates a significant increase in fluctuation intensity near the wall region. The length influenced by the internals on the flow structure is about 1 meter. The lateral gas dispersion coefficient increases significantly as the bluff internals exist in the riser.

Application of Radial Basis Function Network in Sensor Failure Detection

Aim To detect sensor failure in control system using a single sensor signal. Methods A neural predictor was designed based on a radial basis function network(RBFN), and the neural predictor learned the sensor signal on line with a hybrid algorithm composed of n means clustering and Kalman filter and then gave the estimation of the sensor signal at the next step. If the difference between the estimation and the actural values of the sensor signal exceeded a threshold, the sensor could be declared to have a failure. The choice of the failure detection threshold depends on the noise variance and the possible prediction error of neural predictor. Results and Conclusion\ The computer simulation results show the proposed method can detect sensor failure correctly for a gyro in an automotive engine.

MPC-based path tracking with PID speed control for high-speed autonomous vehicles considering time-optimal travel

In order to track the desired path as fast as possible,a novel autonomous vehicle path tracking based on model predictive control(MPC)and PID speed control was proposed for high-speed automated vehicles considering the constraints of vehicle physical limits,in which a forward-backward integration scheme was introduced to generate a time-optimal speed profile subject to the tire-road friction limit.Moreover,this scheme was further extended along one moving prediction window.In the MPC controller,the prediction model was an 8-degree-of-freedom(DOF)vehicle model,while the plant was a 14-DOF vehicle model.For lateral control,a sequence of optimal wheel steering angles was generated from the MPC controller;for longitudinal control,the total wheel torque was generated from the PID speed controller embedded in the MPC framework.The proposed controller was implemented in MATLAB considering arbitrary curves of continuously varying curvature as the reference trajectory.The simulation test results show that the tracking errors are small for vehicle lateral and longitudinal positions and the tracking performances for trajectory and speed are good using the proposed controller.Additionally,the case of extended implementation in one moving prediction window requires shorter travel time than the case implemented along the entire path.

Concentrations and Distribution of Trace Metals of PM10 and TSP Particles Collected in the Qingdao Area

Aerosol samples of PM10 (particulate matter with aerodynamic diameters less than 10μm) and TSP (total suspended particles) were simultaneously collected from April 2001 to March 2002 at the top of Mount Baguan on the downtown campus of Ocean University of China, Qingdao, China. The concentrations of Al, Fe, Mn, Cu, Pb and Zn were determined by means of inductively coupled plasma atomic emission spectrometry (ICP-AES). The monthly variability of the mass concentrations of aerosol particles and the concentrations of trace metals are presented and discussed. The distribution pattern of these metals in PM10 and TSP is also discussed. During the observation period, the mass concentration of PM10 at this site ranged from 13.80 to 306.42μgm-3 , while that of TSP ranged from 31.02 to 568.82μgm-3. Both PM10 and TSP reached their highest concentrations in springtime, while the lowest values occurred in summertime. The concentrations of crustal metals followed the same variation pattern, while those of anthropogenic metals did not. A closer examination led to the conclusion that anthropogenic metals are mainly from local sources. The average concentration ratios of anthropogenic metals in PM10 to TSP were higher than the average mass ratio of PM10 to TSP, suggesting that there was a higher proportion of anthropogenic metals on smaller particles although there were a few exceptions. For crustal metals, however, the metal concentration ratios were close to the particle mass ratio, indicating that the distribution of crustal metals was much more homogeneous on aerosol particles with different sizes. The correlation analysis indicated that Al, Fe and Mn were originated from similar sources and were mainly controlled by the particle mass, while Cu, Pb and Zn were predominated by local anthropogenic sources, with Pb and Zn having similar origins.

Effect of a counseling-supported treatment with the Mediterranean diet and physical activity on the severity of the non-alcoholic fatty liver disease

AIM To determine the clinical effectiveness of nutritional counseling on reduction of non-alcoholic fatty liver disease(NAFLD) severity, weight loss, metabolic and anthropometric indexes and liver enzymes.METHODS Forty-six adults with NAFLD received a 6-mo clinical and a dietary intervention(based on Mediterranean diet) carried out respectively by a gastroenterologist and a nutritionist with counseling license. The counseling process consisted of monthly meeting(about 45 min each). The effect of the treatment was evaluated monitoring liver enzymes, metabolic parameters, cardiovascular risk indexes, NAFLD severity [assessed by ultrasound(US)] and related indexes. All parameters were assessed at baseline. Biochemistry was also assessed at mid-and end-interventions and US was repeated at end-intervention.RESULTS The percentage of patients with steatosis grade equal or higher than 2 was reduced from 93% to 48% and steatosis regressed in 9 patients(20%). At the end of the treatment the end-point concerning the weight(i.e., a 7% weight reduction or achievement/maintenance of normal weight) was accomplished by 25 out of 46 patients(i.e., 54.3%). As far as the liver enzymes is concerned, all three liver enzymes significantly decrease during the treatment the normalization was particularly evident for the ALT enzyme(altered values reduced from 67% down to 11%). Several parameters, i.e., BMI, waist circumference, waist-to-hip ratio, AST, ALT, GGT, HDL, serum glucose, Tot-Chol/HDL, LDL/HDL, TG/HDL, AIP, HOMA, FLI, Kotronen index, VAI, NAFLD liver fat score and LAP, showed a significant improvement(P < 0.01) between baseline and end-treatment.CONCLUSION Outcomes of this study further strengthen the hypothesis that Med Diet and more active lifestyle can be considered a safe therapeutic approach for reducing risk and severity of NAFLD and related disease states. The proposed approach may be proposed as a valid and recommended approach for improving the clinical profile of NAFLD patients.

Effect of second-phase particle size and presence of vibration on AZ91/SiC surface composite layer produced by FSP

An improved method of friction stir processing(FSP)was introduced for the processing of AZ91 magnesium alloy specimens.This novel process was called“friction stir vibration processing(FSVP)”.FSP and FSVP were utilized to develop surface composites on the studied alloy while SiC nanoparticles were applied as second-phase particles.The effect of reinforcing SiC particles with different sizes(30 and 300 nm)on different characteristics of the composite surface was studied.The results indicated that the microstructure was refined and mechanical properties such as hardness,ductility,and strength were enhanced as FSVP was applied.Furthermore,it was concluded that the effect of reinforcing particles with a size of 30 nm on the microstructure and mechanical properties of the surface composite was more obvious than that of particles with a size of 300 nm.It was also found that mechanical properties and microstructure of FSV-processed specimens were improved as vibration frequency increased.The hardness value in the stir zone was about 157 MPa for the FSV-processed specimen at a vibration frequency of 50 Hz,while this value was around 116 MPa for the FSV-processed specimen at a vibration frequency of 25 Hz.

Engineering of Corynebacterium glutamicum to Enhance L-ornithine Production by Gene Knockout and Comparative Proteomic Analysis

Engineered Corynebacterium glutamicum was constructed for L-ornithine production by disrupting genes of argF and proB to prevent the flux away from L-ornithine.Effect of the inactivation of 2-oxoglutarate de-hydrogenase complex(ODHC) on L-ornithine production was also investigated.It was found that the inactivation of ODHC by knockout of the kgd gene enhanced L-ornithine production.The engineered C.glutamicum ATCC13032(ΔargFΔproBΔkgd) produced L-ornithine up to 4.78 g·L-1 from 0.24 g·L-1 of the wild-type strain.In order to understand the mechanism of L-ornithine production in C.glutamicum ATCC13032(ΔargFΔproBΔkgd) and find out new strategies for further enhancing L-ornithine production,the comparative proteome between the wild-type and the engineered strain was analyzed.L-Ornithine overproduction in the engineered strain was related to the up-regulation of the expression levels of enzymes involved in L-ornithine biosynthesis pathway and down-regulation of the expression levels of proteins involved in pentose phosphate pathway.The overexpression of genes in the upstream pathway of glutamate to increase the availability of endogenous glutamate may further in-crease ornithine production in the engineered C.glutamicum and the ornithine synthesis enzymes(ArgCJBD) may not be the limiting enzymes in the engineered C.glutamicum.

Corrosion pathways in aluminium alloys

The corrosion pathways in AA2024-T3, AA5083-O and AA6082-T6 alloys have been investigated. The objective of the investigation is to further the understanding of the complex localised corrosion mechanism in aluminium alloys. The investigation was carried out by examining the corroded surfaces of the alloys after potentiodynamic polarization tests in a 3.5% NaCl solution with the aid of a scanning electron microscope, and by analysing the flow of anolyte solution using the scanning vibrating electrode technique. The results revealed that the overall corrosion pathways in the alloys are distinctively different and are influenced by the flow of anolyte solution. Also revealed, was the fact that corrosion propagates in two ways （particularly in the AA5083-O and AA6082-T6 alloys）： an overall pathway in the corrosion front （filiform-like pathway in the AA5083 alloy and organized linear pathways in AA6082 alloy）; and the crystallographic channelling along the （100） directions. These are dependent on the grain distinct features of the AA5083-O and AA6082-T6 alloys and are not influenced by the presence of coarse second phase particles in these alloys, compared with the AA2024-T3 alloy, where the corrosion pathways are more dependent on the presence of second phase particles and grain boundary character.

Differences in neuroplasticity after spinal cord injury in varying animal models and humans

Rats have been the primary model to study the process and underlying mechanisms of recovery after spinal cord injury. Two weeks after a severe spinal cord contusion, rats can regain weight-bearing abilities without therapeutic interventions, as assessed by the Basso, Beattie and Bresnahan locomotor scale. However, many human patients suffer from permanent loss of motor function following spinal cord injury. While rats are the most understood animal model, major differences in sensorimotor pathways between quadrupeds and bipeds need to be considered. Understanding the major differences between the sensorimotor pathways of rats, non-human primates, and humans is a start to improving targets for treatments of human spinal cord injury. This review will discuss the neuroplasticity of the brain and spinal cord after spinal cord injury in rats, non-human primates, and humans. A brief overview of emerging interventions to induce plasticity in humans with spinal cord injury will also be discussed.

Maximum Effective Hole Mathematical Modei and Exact Solution for Commingled Reservoir

The maximum effective hole-diameter mathematical modei describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate obtained from layer j for a well production at a constant rate from a radial drainage area with infinite and constant pressure and no flow outer boundary condition were expressed in terms of ordinary Bessel functions. These solutions were computed numerically by the Crump's numerical inversion method and the behavior of systems was studied as a function of various reservoir parameters. The modei was compared with the real wellbore radii modei. The new modei is numerically stable when the skin factor is positive and negative, but the real wellbore radii modei is numerically stable only when the skin factor is positive.

Preliminary Results on Hydrological and Hydrochemical Features of Kartamak Glacier Area in Mt. Muztag Ata

The variations of the meltwater runoff draining from Kartamak Glacier in Mt. Muztag Ata in China were studied by using the measured hydrological data from 1 June to 25 August 2003. The meltwater runoff is mainly affected by ambient temperature and precipitation. Meltwater and precipitation samples were collected from 10 to 23 August 2003. Their pH, EC (electric conductivity) and the major ions (Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, NO_3^-, SO_~4^(2-)) were determined. pH values showed a positive correlation with EC values for all samples. Meltwater samples were slightly alkaline. Sulfate and calcium were the dominant anion and cation in the measured ions, respectively. All the ion concentrations had inverse relationships with runoff or water level. In order to discuss the origins of dissolved chemical substances in the glacial meltwater, a principal component analysis was carried out. The results showed that water-rock interaction determined the ion components of the meltwater.