3D N-heterocyclic covalent organic frameworks for urea photosynthesis from NH and CO.

Artificial photosynthesis of urea from NH and CO seems to remain still essentially unexplored. Herein, three isomorphic three-dimensional covalent organic frameworks with twofold interpenetrated ffc topology are functionalized by benzene, pyrazine, and tetrazine active moieties, respectively. A series of experiment results disclose the gradually enhanced conductivity, light-harvesting capacity, photogenerated carrier separation efficiency, and co-adsorption capacity towards NH and CO in the order of benzene-, pyrazine-, and tetrazine-containing framework.

Prediction and analysis of dominant factors influencing moisture content during vacuum screening based on machine learning.

The study of the dominant factors influencing moisture content is essential for investigating vacuum filtration mechanisms. In view of the present situation where there is insufficient experimental data and the dominant factors influencing the moisture content of a filter cake have not been identified, in this study a vacuum filtration apparatus was designed and constructed. Quartz sand particles were used as the filtration material.

Study on the Na specific activity induced by external neutron irradiation based on ICRP 110 computational phantoms.

The dose caused by external exposure to neutrons can be evaluated by measuring the induced Na activity due to interaction of Na in human body with neutrons. To investigate the difference between male and female in the Na activity, the MCNP code is used to simulate the ICRP 110 adult male and female reference computational phantoms irradiated by Cf neutrons. The results show that the average absorbed dose of whole body caused by per unit neutron fluence for the female phantom is (5.

An optimized method for neutron dose evaluation based onNa activity distribution in the human body.

The neutron dose resulting from external irradiation can be evaluated by measuring the counts of characteristicrays produced byNa in the human body. The detection geometry with the highest detection efficiency for measuring the whole-bodyNa activity has not been studied. In this work, the MCNP code is used to calculate the spatial distribution ofNa in the human body irradiated by neutrons with different energies in different irradiation geometries.

Association between the Systolic Blood Pressure Trajectory and Risk of Stroke in a Health-Management Population in Jiaozuo, China.

The trajectories of systolic blood pressure (SBP) in a screening population in Jiaozuo were examined, and the association between the different types of SBP trajectories and the risk of stroke was evaluated. Data of a fixed cohort population from the Jiaozuo Stroke Prevention and Control Project Management Special Database System that underwent community screening in 2015, 2017, 2019, and 2021 were collected. Ultimately, a total of 1,451 participants who met the inclusion criteria for this study were included in the analysis, which was performed using group trajectory modeling.

An Investigation on Energy Harvesting Behavior of an Array Piezoelectric Coupled Disc Damper.

In order to make full use of the vibration energy in the process of attenuating vibration, an array piezoelectric coupled disc damper is developed, which works by converting part vibration energy into electrical energy. The piezoelectric damper is made of a pair of piezoelectric coupled discs built in a case cylinder. Its energy harvesting behavior is studied by a series of forced-vibration experiments and simulations.

Study of rat organ dose conversion coefficients for external photon irradiation based on voxel model and Monte Carlo simulation.

A newly voxel rat model was developed from Micro-CT images of a rat to study rat organ dose for external photon irradiation. The voxel model with voxel size of 0.16 × 0.

Numerical Study on Stochastic Diabetes Mellitus Model with Additive Noise.

This article focuses on the numerical analysis and simulation of the stochastic diabetes mellitus model with additive noise. The existence and uniqueness theorem of the solution under some appropriate assumptions is established. And, the mean square stability and convergence of numerical solutions are proposed, too.

Effect of Pre-Corrosion Pits on Residual Fatigue Life for 42CrMo Steel.

The effect of pre-corrosion pits on residual fatigue life for the 42CrMo steel (American grade: AISI 4140) is investigated using the accelerated pre-corrosion specimen in the saline environment. Different pre-corroded times are used for the specimens, and fatigue tests with different loads are then carried out on specimens. The pre-corrosion fatigue life is studied, and the fatigue fracture surfaces are examined by a surface profiler and a scanning electron microscope (SEM) to identify the crack nucleation sites and to determine the size and geometry of corrosion pits.

Theoretical analysis of transmembrane potential of cells exposed to nanosecond pulsed electric field.

Purpose: Intracellular electroporation occurs when the cells are exposed to nanosecond pulsed electric field (nsPEF). It is believed the electroporation (formation and extension of pores on the membrane induced by external electric field) is affected significantly by the transmembrane potential. This paper analyzed transmembrane potential induced by nsPEF in the term of pulse frequency spectrum, aiming to provide a theoretical explanation to intracellular bio-effects.

Determining organ dose conversion coefficients for external neutron irradiation by using a voxel mouse model.

A set of fluence-to-dose conversion coefficients has been calculated for neutrons with energies <20 MeV using a developed voxel mouse model and Monte Carlo N-particle code (MCNP), for the purpose of neutron radiation effect evaluation. The calculation used 37 monodirectional monoenergetic neutron beams in the energy range 10(-9) MeV to 20 MeV, under five different source irradiation configurations: left lateral, right lateral, dorsal-ventral, ventral-dorsal, and isotropic. Neutron fluence-to-dose conversion coefficients for selected organs of the body were presented in the paper, and the effect of irradiation geometry conditions, neutron energy and the organ location on the organ dose was discussed.

Effects of frequency, irradiation geometry and polarisation on computation of SAR in human brain.

The power absorbed by the human brain has possible implications in the study of the central nervous system-related biological effects of electromagnetic fields. In order to determine the specific absorption rate (SAR) of radio frequency (RF) waves in the human brain, and to investigate the effects of geometry and polarisation on SAR value, the finite-difference time-domain method was applied for the SAR computation. An anatomically realistic model scaled to a height of 1.

Organ dose conversion coefficients based on a voxel mouse model and MCNP code for external photon irradiation.

A set of conversion coefficients from kerma free-in-air to the organ absorbed dose for external photon beams from 10 keV to 10 MeV are presented based on a newly developed voxel mouse model, for the purpose of radiation effect evaluation. The voxel mouse model was developed from colour images of successive cryosections of a normal nude male mouse, in which 14 organs or tissues were segmented manually and filled with different colours, while each colour was tagged by a specific ID number for implementation of mouse model in Monte Carlo N-particle code (MCNP). Monte Carlo simulation with MCNP was carried out to obtain organ dose conversion coefficients for 22 external monoenergetic photon beams between 10 keV and 10 MeV under five different irradiation geometries conditions (left lateral, right lateral, dorsal-ventral, ventral-dorsal, and isotropic).

Structural shielding design for a gamma ray stereotactic body radiotherapy system.

An OUR-QGD gamma ray stereotactic body radiotherapy system (body knife), made in China, is described. According to its structure and the principle of gamma radiation revolved on a focus, the energy distribution of scattered radiation in its treatment room is calculated. The structural shielding of the wall, roof, and door for a certain treatment room is calculated according to the local radiation protection law.

[Copper ion electrochemistry in treatment of bleeding and prolapse due to hemorrhoid, experimental and clinical studies].

Objective: To observe the effect of copper ion electrochemistry (CIE) in treatment of bleeding and prolapse due to hemorrhoid.

Methods: Bleeding was caused at several points on the sacrospinal muscles of 26 rabbits. Routine hemostasis was used at one side (control side) and CIE was used on the opposite side (experimental side).