Design and Cryogenic Performance of a Hexapod Platform for a Large Ground-based Wide Field Survey Telescope

The thermal gradient is an important factor that causes degradation to the image quality of telescopes. In order to ensure the accurate alignment of the primary focus unit and the primary mirror, the hexapod platform(as a corrector) is investigated in this paper. First, a ground-based telescope with 2.5 m aperture and 3.5 deg field of view is described. The telescope is under construction, and it is expected to be finished in 2023. Second, the hexapod platform with flexure hinges utilized to adjust the primary focus unit is proposed, which is applied as a corrector.Then, the inverse kinematics of the platform is established and an open-loop control system is built based on it.Finally, the cryogenic performance test for the hexapod platform is performed. The experimental results show that the resolution and repeatability of the translation for the hexapod platform can be achieved at the micrometer level.The resolution and repeatability of the rotation can be achieved at the arc-second level. Therefore, the cryogenic performance of the hexapod platform can meet the optical imaging requirements of the wide-field ground-based telescope. The kinematic analysis and cryogenic performance tests in the paper provide a technical reference for the precise alignment of the primary focus unit and the primary mirror, which can improve the imaging quality of the telescope.

Gastric outlet obstruction caused by heterotopic pancreas:A case report and a quick review

A 46-year-old Chinese woman presented with nausea, recurrent vomiting, and abdominal pain. Gastroduodenal endoscopic examination revealed an oval-shaped submucosal tumor at the prepyloric area on the posterior wall of the stomach. A degenerated gastrointestinal stromal tumor was suspected. Distal gastrectomy was performed and a histological diagnosis of heterotopic pancreas （HPs） was confirmed. The patient had an uneventful postoperative course and was discharged 7 d a^er operation. The patient remains healthy and symptom-free in the follow-up of 6 mo. This is a report of a case of gastric outlet obstruction resulting from pancreatic heterotopia in the gastric antrum in an adult woman.

Cyclic metallurgical process for extracting V and Cr from vanadium slag: Part Ⅱ. Separation and recovery of Cr from vanadium precipitated solution

Cyclic metallurgical process for separation and recovery of Cr from vanadium precipitated solution by precipitation with PbCO_(3)and leaching with Na_(2)CO_(3)was investigated.The concentration of Cr residue in the solution decreases from 2.360 to 0.001 g/L by adding PbCO_(3)into vanadium precipitated solution according to Pb/Cr molar ratio of 2.5,adjusting the pH to 3.0 and stirring for 180 min at 30℃.Then,the precipitates were leached with hot Na_(2)CO_(3)solution to obtain leaching solution containing Na_(2)CrO_(4)and leaching residue containing PbCO_(3).The leaching efficiency of Cr reaches 96.43%by adding the precipitates into 0.5 mol/L Na_(2)CO_(3)solution with the mass ratio of liquid to solid(L/S)of 10:1 mL/g and stirring for 60 min under pH 9.5 at 70℃.After filtration,leaching residue is reused in Cr precipitation and leaching solution is used to circularly leach the Cr precipitates until Na_(2)CrO_(4)approaches the saturation.Finally,the product of Na_(2)CrO_(4)·4H_(2)O is obtained by evaporation and crystallization of leaching solution.

Cyclic metallurgical process for extracting Ⅴ and Cr from vanadium slag: Part Ⅰ. Separation and recovery of Ⅴ from chromium-containing vanadate solution

The separation and recovery of V from chromium-containing vanadate solution were investigated by a cyclic metallurgical process including selective precipitation of vanadium,vanadium leaching and preparation of vanadium pentoxide.By adding Ca(OH)_(2) and ball milling,not only the V in the solution can be selectively precipitated,but also the leaching kinetics of the precipitate is significantly improved.The precipitation efficiency of V is 99.59%by adding Ca(OH)_(2) according to Ca/V molar ratio of 1.75:1 into chromium-containing vanadate solution and ball milling for 60 min at room temperature,while the content of Cr in the precipitate is 0.04%.The leaching rate of V reaches 99.35%by adding NaHCO_(3) into water according to NaHCO_(3)/V molar ratio of 2.74:1 to leach V from the precipitate with L/S ratio of 4:1 mL/g and stirring for 60 min at room temperature.The crystals of NH_(4)VO_(3) are obtained by adjusting the leaching solution pH to be 8.0 with CO2 and then adding NH_(4)HCO_(3) according to NH_(4)HCO_(3)/NaVO_(3) molar ratio of 1:1 and stirring for 8 h at room temperature.After filtration,the crystallized solution containing ammonia is reused to leach the precipitate of calcium vanadates,and the leaching efficiency of V is>99%after stirring for 1 h at room temperature.Finally,the product of V_(2)O_(5) with purity of 99.6%is obtained by calcining the crystals at 560℃ for 2 h.

Thermodynamic analysis for separation of vanadium and chromium in V(Ⅳ)-Cr(Ⅲ)-H_2O system

To recycle vanadium and chromium from the V?Cr-bearing reducing slag,the thermodynamics of separating V(IV)and Cr(III)at 298 K was summarized in the form of potential-pH diagram and activity-pH diagram.The potential-pH diagrams of V-Mn-H2O and Cr-Mn-H2O systems show that the electrode potential of MnO2/Mn2+is higher than that of VO2+/VO2+but lower than that of Cr2O7 2-/Cr3+,which proves that it is feasible to selectively oxidize low valent vanadium using MnO2.The activity-pH diagrams of V(V)-H2O and Cr(III)-H2O systems show that the precipitation pH of V(V)is far lower than that of Cr(III),and therefore V(V)and Cr(III)can be separated through precipitation method.Based on the thermodynamic analysis,the flowsheet of recovery of vanadium and chromium from the V-Cr-bearing reducing slag is designed.

Separation and recovery of Ni from copper electrolyte by crystallization of nickel ammonium sulfate double salt

The separation and recovery of Ni from the copper electrolyte by crystallization of nickel ammonium sulfate double salt were studied.It is found that the solubility of copper sulfate at the same temperature is less than that of nickel sulfate,while the solubility of copper ammonium sulfate is greater than that of nickel ammonium sulfate.So,by adding(NH_(4))_(2)SO_(4),the Ni can be selectively crystallized from the copper electrolyte.By adding(NH_(4))_(2)SO_(4)at the molar ratio of(NH_(4))_(2)SO_(4)/NiSO_(4)≤0.8,and crystallizing at−15℃for 10 h,the Ni in the copper electrolyte can be crystallized in the form of Ni(NH_(4))_(2)(SO_(4))_(2)×6H_(2)O.The qualified product of NiSO_(4)×6H_(2)O can be obtained by pyrolyzing the crystals,dissolving the pyrolysis product in water,and then concentrating the dissolved solution for crystallization.The method of double salt crystallization is a clean,environmentally-friendly,cost-effective and efficient method for separating and recovering nickel from copper electrolyte.

Effect of radiofrequency ablation combined with transcatheter arterial chemoembolization on inflammatory factors, oxidative stress response factors and tumor activity factors in patients with primary liver cancer

Objective:To investigate the effects of radiofrequency ablation (RFA) combined with transcatheter arterial chemoembolization (TACE) on inflammatory factors, oxidative stress response factors and tumor activity factors in primary hepatocellular carcinoma (HCC) patients.Methods:A total of 100 cases of primary liver cancer patients from January 2014 to June 2016 were selected and randomly divided into observation group and control group with 50 cases in each group, the observation group was treated with RFA combined with TACE treatment, the control group was given TACE treatment, compared two groups before treatment (T0), 1 weeks of treatment (T1), 2 weeks (T2) inflammation factor, oxidative stress factor and tumor activity index.Results:(1) The hs-CRP, IL-6 and TNF-α levels of T1 in two groups were significantly increased, T2 decreased significantly, T1>T1>T2, but the observation group hs-CRP, IL-6, TNF-α levels of T1 were higher than the control group and the difference was statistically significant, hs-CRP, IL-6, TNF-α levels of T2 had no statistically significant;(2) The ROS level of T1 in the observation group was higher than the control group, while the SOD and T-AOC levels were lower than the control group, the ROS level of T2 in the observation group was lower than the control group, SOD and T-AOC were higher than the control group, there was significant difference. (3) Serum AFP, CA199 and MMP levels in T1 and T2 of the observation group were lower than the control group, the difference was statistically significant.Conclusion:RFA treatment of HCC may lead to inflammation and increased oxidative stress in the early stage . However, TACE combined with TACE can improve the micro inflammatory state, especially enhance the antioxidant function and decrease the level of tumor active factor.

Effect of surgical resection combined with transcatheter arterial chemoembolization on postoperative serum tumor marker levels and stem cell characteristics during tumor recurrence

Objective:To study the effect of surgical resection combined with transcatheter arterial chemoembolization (TACE) on postoperative serum tumor marker levels and stem cell characteristics during tumor recurrence.Methods:A total of 98 patients with liver cancer who received radical resection in our hospital between May 2013 and July 2015 were reviewed and divided into TACE group and control group according to whether they received TACE within two months after surgical resection. Serum levels of tumor markers were detected 4 weeks after operation;the tumor recurrence was followed up within 3 years after operation, and the expression of stem cell marker molecules and cell proliferation molecules in recurrent lesions were detected.Results: 4 weeks after radical hepatectomy, serum AFP, AFP-L3, GP73 and GPC3 levels in TACE group were significantly lower than those in control group;Nanog, CD133, EpCAM, PICK1, CyclinD1, C-myc and Survivin expression in surgically removed lesions of TACE group were not different from those of control group while Nanog, CD133, EpCAM, PICK1, CyclinD1, C-myc and Survivin expression in recurrent lesions were significantly lower than those of control group.Conclusion: Surgical resection combined with TACE can more effectively remove liver cancer lesions, reduce the tumor marker levels and inhibit the tumor stem cell characteristics and cell proliferation activity in recurrent lesions.

Medications and medical care of the Buyi ethnicity in Buyimojingbooks:an investigation on its philosophical origin

Studies on various Buyimojingbooks of the minority group“Buyi”in China,combined with information collected through visits to Buyi doctors,revealed that six ideas mainly comprised Buyi treatment and therapeutic principles,i.e.,inviting,expelling,liberating,supplementing,transporting,and recovering.Based on these ideas,the medical philosophy and laws of medication use were investigated to reveal and sort out Buyi therapeutic and pharmaceutical systems to achieve the goal of inheriting and further developing Buyi culture of medicine.

Solvent extraction of molybdenum from acidic leach solution of Ni–Mo ore

A P204 （D2EHPA） diluted with sulfonated kerosene was used for the selective extraction of molybdenum from an acidic Ni-Mo ore leach solution that was reduced using sodium thiosulfate. The results indicate that P204 （D2EHPA） is an effective extractant for the extraction of molybdenum. The extraction of Mo is more than 90 % at pH of 0.5, contact time of 10 min, and organic-to- aqueous phase （O/A） ratio of 1：1 with 10 vol% P204 （D2EHPA）. Molybdenum in the loaded organic phase can be effectively stripped with ammonium acid carbonate solution, and the stripping of molybdenum with 60 g.L-1 ammonium acid carbonate solution is 94.67 % at O/A ratio of 2：1 and contact time of 10 min.

Safety and immunogenicity of a recombinant COVID-19 vaccine(Sf9 cells)in healthy population aged 18 years or older:two single-center,randomised,double-blind,placebo-controlled,phase 1 and phase 2 trials

COVID-19 vaccines from multiple manufacturers are needed to cope with the problem of insufficient supply.We did two singlecenter,randomised,double-blind,placebo-controlled phase 1 and phase 2 trials to assess the safety,tolerability and immunogenicity of a recombinant COVID-19 vaccine(Sf9 cells)in healthy population aged 18 years or older in China.Eligible participants were enrolled,the ratio of candidate vaccine and placebo within each dose group was 3:1(phase 1)or 5:1(phase 2).From August 28,2020,168 participants were sequentially enrolled and randomly assigned to receive the low dose vaccine,high dose vaccine or placebo with the schedule of 0,28 days or 0,14,28 days in phase 1 trial.From November 18,2020,960 participants were randomly assigned to receive the low dose vaccine,high dose vaccine or placebo with the schedule of 0,21 days or 0;14,28 days in phase 2 trial.The most common solicited injection site adverse reaction within 7 days in both trials was pain.The most common solicited systematic adverse reactions within 7 days were fatigue,cough,sore throat,fever and headache.ELISA antibodies and neutralising antibodies increased at 14 days,and peaked at 28 days(phase 1)or 30 days(phase 2)after the last dose vaccination.The GMTs of neutralising antibody against live SARS-CoV-2 at 28 days or 30 days after the last dose vaccination were highest in the adult high dose group(0,14,28 days),with 102.9(95%Cl 61.9-171.2)and 102.6(95%Cl 75.2-140.1)in phase 1 and phase 2 trials,respectively.Specific T-cell response peaked at 14 days after the last dose vaccination in phase 1 trial.This vaccine is safe,and induced significant immune responses after three doses of vaccination.

Existing form of Mo(Ⅵ)in acidic sulfate solution

The existing form of molybdenum in acidic sulfate solution was studied by means of ion exchange, infrared （IR） spectra and X-ray photoelectron spectroscopy （XPS）. The results indicate that the anionic molybdenum species are predominant in acidic sulfate solution, and Mo（VI） can combine with sulfate radical to form heteropoly acid anions [Mo205（804）2]2- and [MoO2（HSO4）4]2-. With the decrease in solution pH from 1.92 to 0.06, the existing form of Mo（VI） changes from MovO21（OH）3^3- to [Mo205（S04）2]2- and then becomes [MoOz（HSO4）4]2-, which results in the decrease in the resin adsorption capacity for molybdenum.