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Non-isothermal Decomposition Kinetics of a New High-energy Organic Potassium Salt: K(DNDZ)
Xu, Kangzhen,Zhao, Fengqi,Song, Jirong,Ren, Xiaolei,Gao, Hongxu,Xu, Siyu,Hu, Rongzu Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
A new high-energy organic potassium salt, 2-(dinitromethylene)-1,3-diazepentane potassium salt K(DNDZ), was synthesized by reacting of 2-(dinitromethylene)-1,3-diazepentane (DNDZ) and potassium hydroxide. The thermal behavior and non-isothermal decomposition kinetics of K(DNDZ) were studied with DSC, TG/DTG methods. The kinetic equation is $\frac{d{\alpha}}{dT}$ = $\frac{10^{13.92}}{\beta}$3(1 - $\alpha$[-ln(1 - $\alpha$)]$^{\frac{2}{3}}$ exp(-1.52 ${\times}\;10^5$ / RT). The critical temperature of thermal explosion of K(DNDZ) is $208.63\;{^{\circ}C}$. The specific heat capacity of K(DNDZ) was determined with a micro-DSC method, and the molar heat capacity is 224.63 J $mol^{-1}\;K^{-1}$ at 298.15 K. Adiabatic time-to-explosion of K(DNDZ) obtained is 157.96 s.
Non-isothermal Decomposition Kinetics of a New High-energy Organic Potassium Salt: K(DNDZ)
Kangzhen Xu,Xiaolei Ren,Fengqi Zhao,Hongxu Gao,Siyu Xu,Rongzu Hu,Jirong Song 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.10
A new high-energy organic potassium salt, 2-(dinitromethylene)-1,3-diazepentane potassium salt K(DNDZ), was synthesized by reacting of 2-(dinitromethylene)-1,3-diazepentane (DNDZ) and potassium hydroxide. The thermal behavior and non-isothermal decomposition kinetics of K(DNDZ) were studied with DSC, TG/DTG methods. The kinetic equation is d 1013.92 3(1 ) dT ααβ= −2[−ln(1 − α )]3 exp(−1.52 × 105 / RT). The critical temperature of thermal explosion of K(DNDZ) is 208.63 oC. The specific heat capacity of K(DNDZ) was determined with a micro-DSC method, and the molar heat capacity is 224.63 J mol‒1 K‒1 at 298.15 K. Adiabatic time-to-explosion of K(DNDZ) obtained is 157.96 s.
Ling Wang*,Xiaohong Zhang*,Fengqi Hu,Hai Yuan,Zhao Gao,Li He,Shuang Zou 대한외과학회 2022 Annals of Surgical Treatment and Research(ASRT) Vol.103 No.5
Purpose: Hungry bone syndrome after parathyroidectomy is an important clinical problem in patients on maintenance hemodialysis. We examined the effect of an enhanced recovery after surgery (ERAS) program on the incidence of hungry bone syndrome after parathyroidectomy in this population. Methods: This single-institution, retrospective study analyzed 108 patients on hemodialysis who underwent parathyroidectomy for secondary hyperparathyroidism. Patients were classified into the pre-ERAS (n = 52) and post-ERAS (n = 56) groups. The ERAS program identified high-risk patients and enforced aggressive measures to normalize calcium levels following parathyroidectomy. Results: There was no significant difference in age, sex, body weight, presenting symptoms, preoperative calcium and alkaline phosphatase levels, postoperative intact parathyroid levels, postoperative calcium levels at 1 and 24 hours after parathyroidectomy, and 30-day readmission rates between the groups. The post-ERAS group had significantly higher levels of postoperative calcium at 48 and 72 hours after parathyroidectomy, but a lower incidence of hungry bone syndrome and shorter postoperative length of stay. Patients with hungry bone syndrome had higher preoperative levels of alkaline phosphatase and intact parathyroid, longer postoperative length of stay, and were less likely to have been part of the ERAS program. High preoperative alkaline phosphatase levels and absence of the ERAS program were independent risk factors for hungry bone syndrome after parathyroidectomy. Conclusion: The ERAS program reduced the incidence of hungry bone syndrome and shortened the postoperative length of stay in patients on maintenance hemodialysis who underwent parathyroidectomy for secondary hyperparathyroidism.
DFT Study for Adsorption and Decomposition Mechanism of Trimethylene Oxide on Al(111) Surface
Cai-Chao Ye,Jie Sun,Fengqi Zhao,Siyu Xu,Xue-Hai Ju 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.7
The adsorption and decomposition of trimethylene oxide (C3H6O) molecule on the Al(111) surface were investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employed a supercell (6 × 6 × 3) slab model and three-dimensional periodic boundary conditions. The strong attractive forces between C3H6O molecule and Al atoms induce the C-O bond breaking of the ring C3H6O molecule. Subsequently, the dissociated radical fragments of C2H6O molecule oxidize the Al surface. The largest adsorption energy is about −260.0 kJ/mol in V3, V4 and P2, resulting a ring break at the C-O bond. We also investigated the decomposition mechanism of C3H6O molecules on the Al(111) surface. The activation energies (Ea) for the dissociations V3, V4 and P2 are 133.3, 166.8 and 174.0 kJ/mol, respectively. The hcp site is the most reactive position for C3H6O decomposing.
Yinghui Ren,Dan Li,Jianhua Yi,Fengqi Zhao,Haixia Ma,Kangzhen Xu,Jirong Song 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.7
4-Amino-1,2,4-triazole copper complex (4-ATzCu) was synthesized, and its thermal behaviors, nonisothermal decomposition reaction kinetics were studied by DSC and TG-DTG techniques. The thermal decomposition reaction kinetic equation was obtained as: dα / dt =1022.01 (1−α )[−ln(1−α )]1/3 exp(−2.75×104 /T) . The standard mole specific heat capacity of the complex was determined and the standard molar heat capacity is 305.66 J·mol‒1·K‒1 at 298.15 K. The entropy of activation ( ΔS ≠ ), enthalpy of activation (ΔH ≠), and Gibbs free energy of activation ( ΔG≠) are calculated as 171.88 J·mol‒1·K‒1, 225.81 kJ·mol‒1 and 141.18 kJ·mol‒1, and the adiabatic time-to-explosion of the complex was obtained as 389.20 s.
Solvent Effect on Structure, Morphology and Catalytic Activity on Ammonium Perchlorate of Nano-MgWO4
Yu Zhang,Jingjing Wang,Weimin Wang,Fengqi Zhao,Kangzhen Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10
For exploring the interesting solvent effect on structure and morphology, a variety of MgWO4 nanoparticles were prepared by a one-pot solvothermal method with different proportional solvents of water and ethylene glycol. The results showed that monoclinic wolframite crystalline structure of MgWO4 was successfully synthesized, corresponding to two standard cards of MgWO4 (JCPDS No. 27-0789) and MgWO4 (JCPDS No. 19-0776), respectively. The morphology of MgWO4 nanoparticles presents eight different shapes and orderly transforms from one shape to another with increasing water content in mixed EG-water solvents, and a possible mechanism was proposed. The catalytic activities of these MgWO4 nanoparticles on the thermal decomposition of Ammonium Perchlorate (AP) were compared using differential scanning calorimetry (DSC) method, and found to present good change rule with particle size.
Ren, Yinghui,Li, Dan,Yi, Jianhua,Zhao, Fengqi,Ma, Haixia,Xu, Kangzhen,Song, Jirong Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.7
4-Amino-1,2,4-triazole copper complex (4-ATzCu) was synthesized, and its thermal behaviors, nonisothermal decomposition reaction kinetics were studied by DSC and TG-DTG techniques. The thermal decomposition reaction kinetic equation was obtained as: $d\alpha$ / dt =$10^{22.01}$ (1-$\alpha$)[-ln(1-$\alpha$)]$^{1/3}$ exp($-2.75\times10^4$ /T). The standard mole specific heat capacity of the complex was determined and the standard molar heat capacity is 305.66 $J{\cdot}mol^{-1}{\cdot}K^{-1}$ at 298.15 K. The entropy of activation $({\Delta}S^{\neq})$, enthalpy of activation $({\Delta}H^{\neq})$, and Gibbs free energy of activation $({\Delta}G^{\neq})$ are calculated as 171.88 $J{\cdot}mol^{-1}{\cdot}K^{-1}$ 225.81 $kJ{\cdot}mol^{-1}$ and 141.18 $kJ{\cdot}mol^{-1}$, and the adiabatic time-to-explosion of the complex was obtained as 389.20 s.
Yanshui Zhou,Kangzhen Xu,Bozhou Wang,Hang Zhang,Qianqian Qiu,Fengqi Zhao 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.10
A novel energetic compound, bifurazano[3,4-b:3',4'-f ]furoxano[3'',4''-d] oxacyclohetpatriene (BFFO), was synthesized through special etherification and its structure was determined by single crystal X-ray diffraction. The crystal of BFFO·H2O is monoclinic, space group P2(1)/c with crystal parameters of a = 9.324(4) Å, b = 9.727(4) Å, c = 10.391(4) Å, β = 106.305(6)°, V = 904.5(6) Å3, Z = 4, μ = 0.17 mm−1, F(000) = 512 and Dc = 1.866 g cm−3. Spectroscopic properties and thermal behaviors of BFFO were studied. BFFO presents good detonation properties.
Structural and Thermal Characteristics of a High-Nitrogen Energetic Material: G(AHDNE)
Lei Lü,Kangzhen Xu,Hang Zhang,Gang Wang,Jie Huang,Bozhou Wang,Fengqi Zhao 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.7
A high-nitrogen energetic salt, 1-amino-1-hydrazino-2,2-dinitroethylene guanidine salt [G(AHDNE)], was synthesized by reacting of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE) and guanidine hydrochloride in sodium hydroxide aqueous solution. The theoretical investigation on G(AHDNE) was carried out by B3LYP/ 6-311+G* method. The thermal behaviors of G(AHDNE) were studied with DSC and TG-DTG methods, and the result presents an intense exothermic decomposition process. The enthalpy, apparent activation energy and pre-exponential constant of the process are −1060 J g−1, 148.7 kJ mol−1 and 1015.90 s−1, respectively. The critical temperature of thermal explosion of G(AHDNE) is 152.63 °C. The specific heat capacity of G(AHDNE) was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 314.69 J mol−1 K−1 at 298.15 K. Adiabatic time-to-explosion of G(AHDNE) was calculated to be a certain value between 60-72 s. The detonation velocity and detonation pressure were also estimated. G(AHDNE) presents good performances.
Preparation and Thermal Performance of Fullerene-Based Lead Salt
Hui-Juan Guan,Rufang Peng,Bo Jin,Hua Liang,Fengqi Zhao,Xing-Bing Bu,Wen-Jing Han,Shijin Chu 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.8
C60 is widely investigated because of its unique structure. But its applications in solid propellant seem to be relatively neglected. C60 has more outstanding features than carbon black which is widely used as a catalyst ingredient of solid propellant. To combine the advantages of fullerene and lead salts, another good composite in propellant catalysts, we synthesized a kind of fullerene phenylalanine lead salt (FPL) and explored its thermal performances by differential thermal analysis (DTA) and thermogravimetry analysis (TGA). The results show it undergoes four exothermic processes started from 408 K. Combined TGA and X-ray diffractometer (XRD), the decomposition mechanism of FPL was derived by TG-IR and comparing IR spectra of FPL and its residues after burned to 327 °C, 376 °C and 424 °C, respectively. Effect of FPL on the decomposition characteristic of hexogen (RDX), a type of explosive in propellant, has been investigated using DTA at different heating rate, which shows the decomposition temperatures of the explosive are all reduced by more than 20 K. The corresponding activation energy (Ea) is decreased by 30 kJ·mol−1. So FPL has potential application as a combustion catalyst in solid propellant.