SF6 Gas Research Articles

Electron Impact Cross Sections and Transport Studies of C3F6O

Electron impact scattering from C3F6O is studied in this work. The R-matrix method was used for the calculations of elastic, momentum transfer, and excitation cross sections. The attachment cross section was obtained through a parametric estimator based on the R-matrix outputs. The Binary-Encounter-Bethe (BEB) method was used for computing the ionization cross section. The obtained cross section set was used for the transport studies using the BOLSIG+ code, which is a two-term Boltzmann equation solver. The present calculation was performed for steady-state Townsend experimental conditions for E/N, covering a range of 100–1000 Td. The critical dielectric strength of pure C3F6O was found to be 475 Td, which is much greater than that of SF6 (355 Td). The effect of the addition of different buffer gases, such as CO2, N2, and O2, was also examined. For the C3F6O–CO2, C3F6O–N2, and C3F6O–O2 mixtures with 65%, 55%, and 60% C3F6O, respectively, the critical dielectric strength was determined to be essentially the same as that of pure SF6. The presence of synergism was confirmed for these gas mixtures. We further derived the Paschen curve using a fitting method with the transport parameters as the basic inputs. The minimum breakdown voltage of C3F6O accounted for only 55% of that of SF6. The buffer gas mixture improved the condition; however, the performance of CO2 and O2 mixtures was not satisfactory. The addition of N2 as the buffer gas significantly improved the breakdown property of the gas. The mixture of ≥99% of N2 or ≤1% of C3F6O gave a better breakdown characteristic than SF6. Any proportion ≥90% of N2 or ≤10% of C3F6O was suitable in the higher pressure ranges. The present work demonstrates the potential of C3F6O as a substitute gas for SF6 with a negligible environmental threat.

Rational pore-window size control in three Cu-MOFs with different pore environments for efficient capture of the greenhouse gas SF6

Effective SF6 gas storage and SF6/N2 mixture separations are extremely important in the industry. Herein, a series of isostructural metal-organic frameworks (MOFs), [Cu6(H2O)3(NTB)4(PYZ)1.5] (SNNU-202, H3NTB = nitrilotribenzoic acid, PYZ = pyrazine), [Cu12(H2O)3(NTB)8(PYZ)3(BPY)1.5] (SNNU-203, BPY = 4,4′-bipyridine) and [Cu6(NTB)4(DABCO)1.5(BPY)1.5] (SNNU-204, DABCO = 1,4-diazabicyclo[2.2.2]octane), with different pore window sizes have been explored for the adsorption and separation performance of sulfur hexafluoride. With stepwise partitioning of the pore window, the adsorption capacity for SF6 and separation of SF6/N2 mixture are gradually improved. Notably, the SF6 uptake value for SNNU-204 is 6.0 mmol g−1 and the amount of substance ratio of SF6-to-N2 uptake can be up to 29.8 at 298 K and 1 bar, surpassing most of top-performing MOFs reported. Ideal adsorbed solution theory (IAST) calculations and breakthrough curves demonstrated that SNNU-204 exhibited excelling separation performance. The stepwise pore window partition can create more micropores, and the aromatic ring of the inserted ligand also facilitates interaction with sulfur hexafluoride gas molecules, providing an important strategy for the application of MOFs in SF6 gas adsorption and separation.

3D particle-in-cell simulations of negative and positive streamers in C4F7N–CO2 mixtures

We investigate negative and positive streamers in C4F7N–CO2 mixtures through simulations. These mixtures are considered to be more environmentally friendly than the insulating gas SF6 that is widely used in high voltage technology. Simulations are performed using a 3D particle-in-cell model. Negative streamers can propagate when the background field is close to the critical field. We relate this to their short conductive channels, due to rapid electron attachment, which limits their field enhancement. Positive streamers also require a background field close to the critical field, and in addition a source of free electrons ahead of them. In our simulations these electrons are provided through an artificial stochastic background ionization process as no efficient photoionization process is known for these gases. In 3D, we can only simulate the early inception stage of positive discharges, due to the extremely high electric fields and electron densities that occur. Qualitative 2D Cartesian simulations show that the growth of these discharges is highly irregular, resulting from incoming negative streamers that connect to existing channels. The inclusion of a stochastic background ionization process also has an interesting effect on negative discharges: new streamers can be generated behind previous ones, thereby forming a chain of negative streamers.

DFT study of SF6 adsorption by Pd-doped hydroxyl-terminal modified Ti3C2Tx MXene.

SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas-solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas-solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment.

Mixed-terminal MXenes react with SF6 in aqueous solution: reaction mechanism and pathway

The search for an ecofriendly treatment for the strong greenhouse gas SF6 has become a global hot issue. Herein, the mixed-terminal Ti3C2T x MXene catalyzing conversion of SF6 in aqueous solution was explored. The catalytic network on realistic Ti3C2T x was constructed. By theoretical calculations, target products and the microscopic reaction mechanism were studied. Firstly, SF6 exhibited different degrees of chemisorption on the constructed Ti3C2T x surfaces of three varying terminal proportions, with different terminals showing synergistic effects. Secondly, taking the effect of H2O and surface hydroxyl into account, the catalytic conversion system of SF6 on a Ti3C2(OH)0.66O1.33 surface was constructed, containing 25 sub-reactions with H2S as one of the final products. SF6 went through successive defluorination on the Ti3C2(OH)0.66O1.33 surface to form low-fluorine sulfide SF x (x = 5, 4, 3, 2, 1), with energy of 80.685 kcal mol−1 released during the whole process. The energy barriers of all the SF6 decomposition sub-reactions were significantly lower than that in free space. Besides, O terminals were regarded as potential hydroxyl terminals in aqueous solution, which continuously provided active hydroxyl groups for the Ti3C2(OH)0.66O1.33 surface. Thus, SF6 conversion in aqueous solution will not result in deactivation of Ti3C2T x catalyst. This work provides a theoretical basis for MXene to catalyze SF6 decomposition in an efficient way.

Discharge Randomness and Attraction Process of Epoxy Surface on Discharge Channel in SF6 Gas Under Uniform Electric Field

It is generally believed that due to the electric field distortion effect and the photoemission process of the solid surface, the discharge channel near the solid surface trends to develop along the surface than that in bulk gas. One way to improve insulation performance is to avoid the solid surface from participating in the gas discharge process. However, the mechanism of the solid surface’s effect on the gas discharge process is still unclear. In this paper, we recorded high-speed framing pictures of the discharge process in SF6 gas near the epoxy surface under lightning impulse voltage in the uniform electric field. The arc pictures show that the attraction effect of the solid surface to the discharge channel is related to the surface shape, gas gap height, and distance from the discharge channel to the solid surface. Besides, discharge randomness also plays a role, which is more obvious in the cylinder insulator than in the conical insulator, for the surface with conical shape could easily attract and arrest the discharge channel to its surface. According to the pictures of discharge process near the cylinder surface, we found that the photoemission process occurs in the streamer stage but has little effect on the attraction effect. The leader initiates after the streamer bridges the gas gap, and its random stepped walk could induce the attraction effect from the solid surface: only when the random stepped leader deflects close to the solid surface, the discharge channel could be further attracted to the solid surface by the electrostatic force, especially its normal component. The result indicates that there are three points to prevent the solid surface from participating in the gas discharge process and further improve insulation performance: choose a cylinder shape (avoid a conical shape), keep the surface away from the high electric field area where discharge may start, and reduce the normal component of the surface electric field.

FIL SSF intraocular lens opacification after pars plana vitrectomy with gas tamponade for traumatic lens luxation and retinal detachment: a case report and literature review

BackgroundTo report a case of sutureless scleral-fixated hydrophilic intraocular lens (FIL SSF IOL, Soleko, Italy) opacification following pars plana vitrectomy surgery using sulfur hexafluoride (SF6) for traumatic lens luxation associated with retinal detachment.Case presentationA 77-year-old woman was referred to our emergency department after blunt trauma in her right eye. At the ophthalmic evaluation, visual acuity was hand movement, biomicroscopy showed pseudoexfoliation syndrome and a traumatic lens luxation in the vitreous chamber. The patient underwent pars plana vitrectomy, subluxated cataract explantation, and FIL SSF IOL implant. During surgery, an inferior retinal detachment was encountered, requiring 20% SF6 gas tamponade. No adverse events were encountered. One month postoperatively, visual acuity (BCVA) improved to 0,3 logMAR. At the 3-month follow-up, the patient presented with BCVA of 0,5 logMAR, and biomicroscopy showed a minimal IOL opacification. Six months postoperatively, BCVA decreased to 1.0 logMAR, and diffuse, IOL opacification was noted at slit lamp examination. The patient refused any other surgical intervention for IOL exchange.ConclusionsAlthough hydrophilic IOL opacification gas related is known, to the best of our knowledge, this is the first case reported in the literature of FIL SSF IOL opacification after pars plana vitrectomy with gas tamponade for retinal detachment.

Autologous neurosensory retinal transplantation.

Macular hole is a full-thickness neuroretinal defect in the fovea. The surgical solution is the removal of the internal limiting membrane (ILM) during vitrectomy with gas filling. Several surgical techniques have been described for the closure of refractory macular holes (about 5%), that reappear after successful surgery or do not close despite surgery. This article presents the first autologous neurosensory retina transplantation performed in Hungary for a large, refractory, full-thickness macular hole, with a brief overview of macular hole surgery. In September 2022, we performed a combined phacovitrectomy with ERM/ILM peeling and SF6 gas filling due to cataract, epiretinal membrane (ERM), and large macular hole due to the deterioration of vision in our patient's left eye for months, with a visual acuity of 6%. We drew the patient's attention to the importance of postoperative head positioning, which she ignored. With a visual acuity of 4%, due to a refractive macular hole (at the base: 983 μm, at the smallest diameter: 609 μm), on December 14, 2022, autologous neurosensory retina transplantation was performed using intraoperative OCT (Zeiss ARTEVO 800). At the end of the surgery, decalin was left in the eye to keep the graft in place, and the patient spent 5 days in a supine position. The decalin was removed with another operation, followed by C3F8 gas filling. 8 weeks after surgery, we documented a closed macular hole with 20% visual acuity, which was stable during the 6-month follow-up. Among the options considered for the resolution of refractory macular holes, autologous neurosensory retinal transplantation, which results in a visual improvement of our patient, is an intervention worth considering. Intraoperative OCT was a great help in performing the surgery. Although the decalin left temporarily in the eye helps to keep the transplant in place, it requires a continuous supine position and another operation is essential to remove it. Further experience is needed to establish the exact indication for autologous neurosensory retinal transplantation. Orv Hetil. 2023; 164(38): 1511-1517.

Arc Erosion Behavior of Cu/Ti3SiC2 Cathodes in c-C4F8 Gas as a Substitute for SF6 Gas

Arc Erosion Behavior of Cu/Ti3SiC2 Cathodes in c-C4F8 Gas as a Substitute for SF6 Gas

Theoretical analysis of Ni atom-doped MXene for improving the catalytic degradation performance of SF6

The strong greenhouse effect of SF6 will directly affect the whole habitat. Finding a suitable catalyst for the efficient degradation of SF6 is one of the main means to reduce SF6 emissions. In this paper, two-dimensional MXene doped with Ni atoms was used as catalytic material, and Density Functional Theory (DFT) was combined to investigate the influence properties of different terminal modifications of Ti3C2Tx (T = F, OH, O) on the catalytic degradation of SF6. The adsorption and decomposition processes of SF6 gas molecules on the surface of Ni-doped Ni-MXene material were calculated, and the adsorption energy transferred electron number and density of states (DOS) of the adsorption system were analyzed. The results show that: the adsorption energy of SF6 gas molecules on the surface of Ni-MXene is −6 eV and the number of transferred electrons is more than 0.5 e, in which the adsorption energy under the F-terminal group increases by 1 eV and the number of transferred electrons increases by 0.5 e compared with the undoped case, and the catalytic effect is improved; the molecular structure of SF6 changes significantly during the adsorption process, and the S-F bond was elongated to 2 Å and the S-F bond length away from the material was elongated by 0.2 Å, which made the SF6 molecule easier to be decomposed; according to the results of DOS calculations, the F atoms in the SF6 molecule had obvious electronic orbital interactions with both the Ni atoms on the surface of the Ni-MXene material and the MXene material itself, indicating that both showed the catalytic activity for SF6 during the adsorption process. The conclusions of this paper have some theoretical guidance for the efficient catalytic degradation of SF6.

Theoretical determination of speed of sound and fourth virial coefficient by using Kihara (12–6) potential

Abstract In this paper, a new theoretical approach is suggested for the numerical calculation algorithm of the fourth virial coefficient and its components with the Kihara potential. For the first time, this study reports the results of the fourth virial coefficient over the Kihara potential. The proposed method can be used to calculate the thermodynamics properties of gases with developed correctness. The method is tested for some molecules and as an example of application, the proposed method has been performed for gases of C3H8 and SF6. The obtained calculation results have been compared with the theoretical and experimental data and the results have been found to be consistent with the literature data. It can be seen from the application that the calculation of the fourth virial coefficient with the Kihara potential can provide important results in the calculation of the thermophysical properties of other real systems.

Surgical treatment of idiopathic macular holes with a fovea-sparing technique and 20% SF6 gas tamponade

Purpose: To assess the macular hole (MH) closure rate and final visual acuity after idiopathic MH treatment with a modified fovea-sparing technique and 20% SF6 gas tamponade. Material and Methods: Fifteen patients (16 eyes; 12 women and 3 men; mean age (standard deviation or SD), 65.5 (5.90 years)) with Gass stage 2 to stage 4 MHs were involved in the study. Before surgery, mean best-corrected visual acuity (BCVA) (SD) was 0.15 (0.09), and mean MH diameter (SD), 437.2 (164.7) µm. Patients underwent surgical treatment with the modified fovea-sparing technique and 20% SF6 gas tamponade of two-week duration and were instructed to maintain a face-down position for a week after surgery. Results: At 1 month after the first surgery, MHs were closed in 11/16 eyes (68.75%). In addition, mean BCVA (SD) in eyes with closed MHs improved significantly from 0.15 (0.09) to 0.48 (0.16) (р = 0.000000). Of the five eyes in which the MH had failed to close after primary fovea-sparing surgery, two received a gas fluid exchange gas tamponade with 15% С3F8, and these patients were advised to maintain a face down position for 3 more weeks. In addition, in another two eyes, the vitreous cavity was revised, and the internal limiting membrane (ILM) was removed by a conventional technique with 15% С3F8 gas tamponade. Moreover, one patient rejected repeat intervention. In the four eyes in which the MH had failed to close after primary fovea-sparing surgery, after a repeat intervention, the MH was closed, and mean BCVA (SD) improved to 0.35 (0.04). There was no significant difference between the eyes in which the MH failed to close and the eyes in which the MH did close after primary surgery in terms of mean MH size (SD) (455 (203) µm versus 415 (155) µm, р = 0.66) or MH duration. Conclusion: A long gas tamponade (longer than 1 week) is required to improve the closure rate with the fovea-sparing ILM peeling technique for idiopathic MHs.

Enhanced adsorption and sensitivity for SF6 decomposition gas detection on penta PdSe2 monolayer: A Density Functional Theory investigation with van der Waals correction

The breakdown of the insulating gas SF6 causes the Gas-Insulated Switchgear (GIS) fault type to occur during high-voltage power operation putting the power system's safety in threat. The adsorption behaviour and sensitivity of five gases (H2S, SO2, SO2F2, SOF2 and HF) dissolved by SF6 on PdSe2 monolayers is explored using Density Functional Theory (DFT) in this work. Perdew-Burke-Ernzerhof (PBE) within a Generalised Gradient Approximation (GGA) was employed for the computational investigation. PdSe2 monolayer and SF6 decomposition gas adsorbed PdSe2 are built and optimized to get the most stable structures. The adsorption energy (Ead), charge transfer (QT), bandgap (Eg), Density of States (DOS), Work Function (WF), Sensitivity (S), and recovery time (τ) were computed to investigate the adsorption mechanism of PdSe2 monolayer to SF6 decomposition gas. The computation revealed that the SO2 and H2S adsorption systems have the highest adsorption energy of − 0.51 eV and − 0.52 eV respectively. The SO2F2 adsorption system has the weakest adsorption energy of − 0.44 eV. The findings show that PdSe2 systems have improved sensing performance for SO2 and H2S gas. The PdSe2 monolayer exhibits better sensitivity and a stable desorption time. The PdSe2 monolayer for SO2 and H2S detection shows high sensitivity, attaining 91.89% and 85.53%, respectively. This research establishes the groundwork for the development of PdSe2 monolayer adsorbents for use in SF6-insulated equipment.

The influence of parameters of gas-insulated system on the duration of electrical breakdown at points near to Paschen minimum

The paper considers the time of thermoionization of the spark channel during gas breakdown in the vicinity of Paschen minimum. For the purposes of measuring the time of thermoionization, an experimental procedure was developed that enabled the measurement of times of the order of nanoseconds with a measurement uncertainty of less than 5%. The thermoionization time was measured to the right and to the left of the Paschen minimum. There were included the vacuum breakdown mechanism, the anomalous Paschen breakdown mechanism, the Tausend breakdown mechanism, and the streamer breakdown mechanism. The obtained results show that the thermoionization time is a stochastic quantity. It was established that the random variable thermoionization time belongs to a normal or Weibull distribution. The results also show how the insulation parameters affect the random variable thermoionization time. Experiments were performed with He, SF6 and N2 gases. The electrode system formed a homogeneous field (Rogowski-Rogowski) or an inhomogeneous field (spike-spike). The surfaces of the electrodes were either polished or sandblasted.

Light-induced thermoelastic sensor for ppb-level H2S detection in a SF6 gas matrices exploiting a mini-multi-pass cell and quartz tuning fork photodetector

We present an optical sensor based on light-induced thermoelastic spectroscopy for the detection of hydrogen sulfide (H2S) in sulfur hexafluoride (SF6). The sensor incorporates a compact multi-pass cell measuring 6 cm × 4 cm × 4 cm and utilizes a quartz tuning fork (QTF) photodetector. A 1.58 µm near-infrared distributed feedback (DFB) laser with an optical power of 30 mW serves as the excitation source. The sensor achieved a minimum detection limit (MDL) of ∼300 ppb at an integration time of 300 ms, corresponding to a normalized noise equivalent absorption coefficient (NNEA) of 3.96 × 10−9 W·cm−1·Hz−1/2. By extending the integration time to 100 s, the MDL can be reduced to ∼25 ppb. The sensor exhibits a response time of ∼1 min for a gas flow rate of 70 sccm.

A quantum chemical prediction on arc interruption capability of the dielectric gases

AbstractThe use of sulfur hexafluoride (SF6) as an electrical insulator and arc‐quenching gas in high‐voltage equipment raises serious environmental concerns. The search of a replacement gas for SF6 is hindered by a priori assessment on its interruption performance. The routine fluid or mathematic magneto‐hydrodynamic models for arc burning and extinguishing are too complex to be practical for virtual screening. Herein a state‐of‐the‐art quantum chemical model to predict the interruption capability of the dielectric gases straightforwardly has been established in terms of the rate of rise of the recovery voltage (RRRV). On the basis of the molecular electrostatic potentials, five sets of descriptors, including the global statistical parameters and , the site‐specific parameter ΔVs, the total positive surface area As+, augmented with the product of polarizability and dipole moment αμ, were optimized to reveal the inherent mechanisms for interruption and thus a viable structure–activity relationship mode for RRRV has been developed with the correlation coefficient 0.975. Theoretical RRRV relative to SF6 = 100 for all the known dielectric gases are in good agreement with the experimental data by a mean absolute deviation of 3.6. Accordingly, the perfluorinated cycloalkenes and alkynes, in particular, 1,3,3,3‐tetrafluoropropyne, are found to be the promising candidates as the replacement dielectric gases for SF6.

Comparison of Insulated Switch Gear with Desiccant Addition to SF6 Gas Quality System at Waru Substation

In electrical instrumentality with SF6 gas insulation, the quality of SF6 gas in line with the standard is prime to wise insulation power, if there' a decrease in gas quality, there'll even be a decrease among the number of voltage insulation on electrical equipment. throughout this case, it had been found that the quality of SF6 gas was deteriorating within the Ganz whole GIS Compartment at the Waru Substation Substaction, specifically the position level of the SF6 isolation gas that exceeded the required standard limit. Besides, this GIS isn't equipped with silica gel/desiccant as a condition gripping material and gas sorbent material from amendment PMT (IEEE Std 11251993) that ends throughout a decrease among the standard of SF6 gas. The addition of drier among the GIS is needed to keep up the quality of SF6 gas. These materials are analyzed for quantity and performance once applied within the compartment therefore as that deterioration of the quality of SF6 gas and thus the prevalence of insulation failure is avoided as early as possible, and SF6 remains in its characteristics with a BDV of 78.6 kV/cm (according to SF6 crucial Breakdown Volatge). And it hoped that SF6 gas will add line with it operate as a decent insulating medium. As degree application, a drier experiment has been administered among the GIS compartment at the Waru Substation station

Novel application of Deep Anterior Lamellar Keratoplasty for retinal detachment repair in totally opaque cornea secondary to aniridia.

We present a novel approach for managing retinal detachment in a patient with aniridia related corneal scarring precluding fundal view via a deep anterior lamellar keratoplasty. A 30-year-old female patient who had bilaterally opaque cornea, due to advanced aniridia related keratopathy presented with, experiencing flashing of light in her right eye. Examination of the retinal fundus was not possible due to the dense corneal scarring and underlying cataract. A superior bullous macula off retinal detachment was diagnosed on ultrasonography. Visual acuity at presentation was hand motions. The corneal scarring extended to the mid to deep stroma. We performed a deep anterior lamellar dissection of the opacified corneal stroma, that allowed clear visualisation of a dense cataract. The cataract was removed by phacoemulsification and IOL inserted. This allowed to proceed with repair of retinal detachment, through pars plana approach. The surgery was completed by a donor deep lamellar keratoplasty. This achieved a good fundal view to proceed with phacovitrectomy visualised through the residual corneal layers. Uneventful pars plana vitrectomy, cryotherapy and SF6 gas were performed to reattach the retina. Post-operatively the graft remains clear at 6 months with a visual acuity of 20/160 in the right eye, a level of vision the patient had not experienced for decades. Deep anterior lamellar keratoplasty offered an alternative to temporary keratoprosthesis to achieve a clear view of the retinal fundus and perform pars plana vitrectomy and repair of the retinal detachment.

Intralenticular Metallic Foreign Body: A Case Report

Background: Intraocular foreign body (IOFB) injuries exhibit variations based on multiple factors, including size, composition, location, type, contamination, the extent of tissue damage, and potential complications that may arise. Case Presentation: This case study describes a 48-year-old male patient who presented to the outpatient clinic with a progressive decline in vision in the right eye lasting three weeks. The patient reported a history of redness in the affected eye, occurring for several days after performing maintenance work. Intraocular pressure measurements were normal for both eyes. The slit lamp examination revealed a corneal opacity near the limbus at the 2 o'clock position in the right eye, along with a small peripheral iris hole aligned with the corneal opacity. Additional diagnostic investigations, including a B-scan ultrasound and a CT scan of the orbit without contrast, were conducted. The B-scan ultrasound showed a clear vitreous and a flat retina, while the CT scan detected a metallic foreign body measuring 3x3 mm. The foreign body was found to be partially embedded in the lens and partially in the vitreous, as confirmed by the imaging. As a result, the patient was admitted to the hospital, and a comprehensive treatment plan was implemented. Topical antibiotics, steroids, cycloplegic, and nonsteroidal anti-inflammatory eye drops were prescribed. The patient underwent cataract surgery with sulcus intraocular lens implantation, combined with a pars plana vitrectomy to remove the foreign body. Additional procedures, such as 360 laser treatment, air-fluid exchange, and injection of SF6 gas, were performed. Conclusion: This case highlights the successful management of an intraocular foreign body injury, emphasizing the significance of prompt diagnosis and appropriate surgical intervention in achieving positive visual outcomes.

Research on detection technology of sulfur hexafluoride decomposition products of GIL based on carbon nanotubes

Sulfur hexafluoride (SF6) gas is a stable gas that is widely used in gas insulated lines (GILs) in power systems. However, in GIL, SF6 gas is in the environment of high temperature, high pressure and high voltage for a long time, SF6 gas will decompose into toxic gas, damage electrical equipment, and pose a huge threat to human body and ecological environment. In addition, SF6 gas is a greenhouse gas that is strictly forbidden to leak. Once leaked, it will cause great harm to the environment. Therefore, it is necessary to recover and purify the SF6 gas in the power system GIL. In this paper, a molecular model of carbon nanotubes is constructed, and the density functional theory is used to analyze the changes of charge distribution, density of states and molecular orbitals after adsorption of SF6 decomposition products by carbon nanotubes, and determine the gas-sensing response of carbon nanotubes to gas molecules characteristic.