[Research on Dry Chemical Detection TechnologyBased on Reflectance Photometry].

In response to the issues of insufficient stability and accuracy in dry chemical detection using reflectance photometry, caused by the divergence and multiple internal reflections of the reflected light signal from the sample and the multilayer dry film test strip, a dry chemical reflectance photometry detection system based on an integrating sphere is designed. Firstly, an integrating sphere device is incorporated to reduce signal divergence and loss, ensuring even detection of the sample's reflected light signal and improving detection stability. Secondly, Light Tools optical simulation analysis is performed, and an integrating sphere detection model is established. Thirdly, the Williams-Clapper equation is employed to correct the error in reflectance density caused by multiple internal reflections, enhancing detection accuracy. Experimental validation demonstrates that the developed integrating sphere-based dry chemical reflectance photometry detection system improves the stability and accuracy of the detection system.

Risk factor for 31-day unplanned readmission to hospital in patients with pulmonary tuberculosis in China.

OBJECTIVES: To evaluate risk factors associated with 31-day unplanned readmission(s) for pulmonary tuberculosis (TB) in China. METHODS: This retrospective study enrolled patients (age, >14 years) with pulmonary TB who experienced 31-day unplanned readmissions to a specialized hospital for TB between January 2018 and December 2019. For each confirmed readmission, 2 control subjects were randomly selected from among patients with pulmonary TB but did not experience an unplanned readmission within 31 days. RESULTS: A total of 402 pulmonary TB patients (5.9%) experienced unplanned readmission within 31 days after discharge. In univariate analysis, readmission was associated with gender, age, insurance coverage, residing in a rural area, active smoking, chronic obstructive pulmonary disease (COPD), drug-induced hepatitis, and leaving hospital against medical advice. The final logistic regression model revealed that higher risks for unplanned readmissions were associated with male gender (odds ratio [OR] 1.44, [95% confidence interval (CI) : 1.06-1.95]), age >65 years (OR 2.94, 95%CI: 2.03-4.27), rural residence (OR 8.86, 95%CI: 6.61-11.87), active smoking (OR 2.15, 95% CI 1.37-3.40), COPD (OR 2.77, 95%CI: 1.59-4.81), and leaving hospital against physician advice (OR 4.11, 95%CI: 1.43-11.83). The median time to 31-day unplanned readmission was 24 days. Major reasons for unplanned readmission included fever, exacerbation of dyspnea, and hemoptysis. CONCLUSION: Unplanned readmission for pulmonary TB within 31 days of discharge was higher among older males residing in rural areas, active smokers, and those leaving hospital against medical advice.

Preparation of SA-PA-LA/EG/CF CPCM and Its Application in Battery Thermal Management.

To improve the heat dissipation efficiency of batteries, the eutectic mass ratios of each component in the ternary low-melting phase change material (PCM), consisting of stearic acid (SA), palmitic acid (PA), and lauric acid (LA), was explored in this study. Subsequently, based on the principle of high thermal conductivity and low leakage, SA-PA-LA/expanded graphite (EG)/carbon fiber (CF) composite phase change material (CPCM) was prepared. A novel double-layer CPCM, with different melting points, was designed for the battery-temperature control test. Lastly, the thermal management performance of non-CPCM, single-layer CPCM, and double-layer CPCM was compared via multi-condition charge and discharge experiments. When the mass ratio of SA to PA is close to 8:2, better eutectic state is achieved, whereas the eutectic mass ratio of the components of SA-PA-LA in ternary PCM is 29.6:7.4:63. SA-PA-LA/EG/CF CPCM formed by physical adsorption has better mechanical properties, thermal stability, and faster heat storage and heat release rate than PCM. When the CF content in SA-PA-LA/EG/CF CPCM is 5%, and the mass ratio of SA-PA-LA to EG is 91:9, the resulting SA-PA-LA/EG/CF CPCM has lower leakage rate and better thermal conductivity. The temperature control effect of single-layer paraffin wax (PW)/EG/CF CPCM is evident when compared to the no-CPCM condition. However, the double-layer CPCM (PW/EG/CF and SA-PA-LA/EG/CF CPCM) can further reduce the temperature rise of the battery, effectively control the temperature and temperature difference, and primarily maintain the battery in a lower temperature range during usage. After adding an aluminum honeycomb to the double-layer CPCM, the double-layer CPCM exhibited better thermal conductivity and mechanical properties. Moreover, the structure showed better battery temperature control performance, while meeting the temperature control requirements during the charging and discharging cycles of the battery.

Improving the capacity of zinc-ion batteries through composite defect engineering.

Aqueous zinc-ion batteries (ZIB) are favored because of their low cost and high safety. However, as the most widely used cathodes, the rate performance and long-term cycle performance of manganese-based oxides are very worrying, which greatly affects their commercialization. Here, MnO2 with composite defects of cation doping and oxygen vacancies was synthesized for the first time. Cation doping promoted the diffusion and transport of H+ and oxygen vacancies weakened the zinc-oxygen bond, allowing more electrons to be added to the charge and discharge process. The combination of these makes α-MnO2 obtain a specific capacity of up to 346 mA h g-1. This inspired us to use different combinations of defect engineering strategies on the materials which can be implemented as a potential method to improve performance for the modification of ZIB cathode materials, such as cation vacancies and anion doping.

Preparation of Binary Thermal Silicone Grease and Its Application in Battery Thermal Management.

To improve the problems of large interface thermal resistance and low heat dissipation efficiency in battery thermal management (BTM), this paper uses methyl silicone oil as the matrix, AIN, copper powder (CP), and carbon fiber (CF) as thermally conductive fillers, and acetone and stearic acid as particle surface modification components. A variety of binary thermal silicone greases (TSGs) with different compositions were prepared. Different instruments were used to test the material properties of TSGs, and a better TSG was selected to coat the interface between battery and phase change material (PCM) for battery charging and discharging experiments. Through the analysis of experimental data, it was found that among the TSGs made of three mixed fillers (AIN/CP, AIN/CF, CP/CF), the three TSGs had good thermal stability, and their thermal degradation temperature both exceeded 300 °C. As the ratio of thermally conductive filler was gradually changed from 5:1 to 1:5, the TSG containing CP/CF had higher thermal conductivity and lower volume resistivity, while the TSG containing AIN/CF had the least damage due to interface wear. The acidification treatment of thermally conductive filler can improve the adsorption and compatibility of thermally conductive particles and silicone oil, and reduce the oil separation rate of TSGs. The prepared expanded graphite (EG)/paraffin wax (PW) composite phase change material (CPCM) has a relatively large latent heat of phase change, which can effectively control the temperature of the battery, but coating TSG between the battery and the CPCM can further enhance the heat dissipation effect of the battery.

Three metal-organic framework isomers of different pore sizes for selective CO2 adsorption and isomerization studies.

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) with tunable pore sizes, shapes and functionalities have excellent prospects in many applications, such as carbon capture. Molecular sieving can usually enable very high CO2 adsorption selectivity but has rarely been achieved, because it is difficult to precisely control the pore size in the range of 3-4 Å. We report here three MOF isomers built from CdII, terephthalic acid and 3,6-di(pyridin-4-yl)-1,2,4,5-tetrazine with the same stoichiometric ratio, among which 1 and 2 are framework-catenation isomers and 2 and 3 are framework-topological isomers. 1 contains 2-fold interpenetrated networks (topology of pcu) and 1D ultra-micropores and shows highly selective adsorption of CO2 over N2 and CH4, which is mainly ascribed to the molecular sieving effect of the framework. 2 contains a pcu network with 3D interconnected micropores, and 3 contains a kag network with much larger pores of 15 Å. Framework isomerization, in this case, was shown to be a feasible way of tuning the pore size of a MOF for selective CO2 adsorption. The effects of hydrothermal reaction conditions and additives on the structures and the formation of the MOF isomers were also studied.

Expanded Graphite/Paraffin/Silicone Rubber as High Temperature Form-stabilized Phase Change Materials for Thermal Energy Storage and Thermal Interface Materials.

In this work, expanded graphite/paraffin/silicone rubber composite phase-change materials (PCMs) were prepared by blending the expanded graphite (EG), paraffin wax (PW) and silicone rubber (SR) matrix. It has been shown that PW fully penetrates into the three dimensional (3D) pores of EG to form the EG/PW particles, which are sealed by SR and evenly embedded in the SR matrix. As a result of the excellent thermal stability of SR and the capillary force from the 3D pores of EG, the EG/PW/SR PCMs are found to have good shape stability and high reliability. After being baked in an oven at 150 °C for 24 h, the shape of the EG/PW/SR PCMs is virtually unchanged, and their weight loss and latent heat drop are only 7.91 wt % and 11.3 J/g, respectively. The latent heat of the EG/PW/SR composites can reach up to 43.6 and 41.8 J/g for the melting and crystallizing processes, respectively. The super cooling of PW decreased from 4.2 to 2.4 due to the heterogeneous nucleation on the large surface of EG and the sealing effect of the SR. Meanwhile, the thermal conductivity of the EG/PW/SR PCMs reaches 0.56 W·m-1·K-1, which is about 2.8 times and 3.73 times of pure PW and pristine SR, respectively. The novel EG/PW/SR PCMs with superior shape and thermal stabilities will have a potential application in heat energy storage and thermal interface materials (TIM) for electronic devices.

Variation in nutritional compositions, antioxidant activity and microstructure of Lycopus lucidus Turcz. root at different harvest times.

The objective of this study was to investigate the variation in nutritional compositions, antioxidant activity and microstructure of Lycopus lucidus Turcz. root at different harvest times. L. lucidus Turcz. roots, harvested from two sites (S1 and S2) at three different times (T1: 19-11-2013, T2: 22-12-2013 and T3: 27-01-2014), were analyzed for nutritional compositions, antioxidant activity by DPPH, FRAP and TEAC assays and microstructure. The results revealed that the protein content in L. lucidus Turcz. root first decreased and then increased to a maximum at T3. The reducing sugar content had no significant differences among the three harvest dates studied. The starch content decreased drastically along with an increase of crude fat content with the harvest time delayed. The major amino acids in L. lucidus Turcz. root were aspartic acid and glutamate and the highest total amino acid content was found for the root harvested at T3. The most common element in L. lucidus Turcz. root was detected to be potassium followed by calcium, iron, magnesium, copper and manganese, and their changes were discrepant in the period of harvest. The FP and SGP possessed the highest and lowest phenolic content, respectively. The change of SEP was significantly correlated to the SGP at different harvest times. The highest TPC was found for the root harvested at T3 and the most abundant phenolic acid was chlorogenic acid. The highest and lowest DPPH radical scavenging capacity was observed for the SGP and FP, respectively. The highest and lowest FRAP and TEAC were observed for the FP and SGP, respectively. The results of correlation analysis indicated that there was significant correlation between phenolic content and FRAP and TEAC, and different antioxidant assays. The microstructure of L. lucidus Turcz. root also varied greatly with the harvest times.