Search

Aiming at the characteristics of acrylonitrile production wastewater with high concentration of refractory organic matter, high total nitrogen concentration,high toxicity and complex composition, the combined process of “ozone catalytic oxidation+coagulation precipitation+improved A/O” was used to treat the wastewater. The process, main structure and equipment design parameters, debugging difficulties and methods were introduced, and the operation effect and cost were analyzed. The operation results showed that the process has the characteristics of shock load resistance, stable operation and convenient management. After the acrylonitrile production wastewater was treated by this combination process, the mass concentrations of COD, NH3-N, TN, SS, TN and TCN were stable at 34-97, 0.3-2.7, 9-26, 8-23, 0-0.1 mg/L, which could fully meets the indirect emission standard in Table 2 of the Petrochemical Industry Pollutant Emission Standard (GB 31571-2015), while the organic characteristic pollutant acrylonitrile in the effluent was detected to meet the emission limits in Table 3 of the Petrochemical Industry Pollutant Emission Standard(GB 31571-2015), and satisfied takeover standards in the regional centralized sewage treatment plant.

Aiming at the test requirements of specified path coverage of fully automatic operation (FAO) system test, this paper proposes an algorithm for automatic generation of test cases for FAO based on the modeling theory of timed automata to meet the specified path coverage and edge coverage. Firstly, the modeling theory of timed automata is studied, and the FAO timed automata model is established. Then, a modeling method to add marker variables to the d automata model is proposed to characterize the FAO test requirements of specified path coverage. Thirdly, combined with the test case generation mechanism of Yggdrasil, a test case generation method of FAO is proposed, which satisfies both the specified path coverage and edge coverage criteria of FAO. Finally, taking the mode conversion function of FAO as an example, the timed automata model is established and test cases are generated. The results show that the test cases cover 100 % of the test requirements specified by the tester and all the edges of the timed automata model, which can meet the test requirements of the specified path coverage of FAO. [ABSTRACT FROM AUTHOR]

In view of the contradiction between straight lifting type heald spring and structural arrangement, a non-contact type of flat scroll leaf spring for heald return was designed and developed. A CAD entity model of spiral spring based on archimedes spiral was constructed according to national machinery industry standard (JB/ T 7366-1994). The results of finite element analysis with static and dynamic show that elastic deformation and stress distribution of the spring can meet requirements of static strength design, and low-order modal frequencies of the spring is less than 1Hz, which can effectively avoid working frequency of high-speed cam lifting. Through dynamic simulation and data processing of flexible spiral spring, stiffness characteristic curve and energy storage curve of the spring in tightening process were obtained, which provided an important basis for accurate calculation of reaction torque T and energy storage density ρE, which is beneficial to dynamic design and practical application of spiral spring. [ABSTRACT FROM AUTHOR]

Beneficiation of a barite ore from Ankang, Shaanxi was researched. The effects of ore grinding fineness, combination and dosage of collector and inhibitors on the ore flotation were examined. After a series of experiments, the optimal flotation parameters were determined. The qualified concentrate was gained by the closed circuit flotation test. The gangue minerals are separated successfully. [ABSTRACT FROM AUTHOR]

Objective: To compare clinicopathological features and prognosis between patients with carcinoma in the remnant stomach (CRS) and with gastric cancer, and to investigate the prognostic factors in CRS patients., Methods: A retrospective cohort study was performed on clinicopathological data of 96 CRS patients (CRS group) and selected 440 patients with gastric cancer (GC group) treated at Harbin Medical University Cancer Hospital from January 1977 to December 2017., Inclusion Criteria: (1) undergoing gastrectomy; (2) diagnosed with CRS or gastric cancer through electronic gastroscopies and pathology; (3) without preoperative neoadjuvant radiotherapy or chemotherapy; (4) complete clinicopathological and follow-up data. The patients who died of other reasons or were lost during follow-up were excluded. Chi-square test and independent samples t-test were used to determine differences in clinicopathological factors between two groups. Survival analysis was conducted using the Kaplan-Meier method, and Log-rank test was used to compare survival difference between two groups. The prognosis of CRS patients was analyzed using Cox proportional hazards regression model., Results: As compared to GC group, CRS group had a higher proportion of female [30.2%(29/96) vs. 13.2%(58/ 440), χ 2 =14.095, P=0.000], younger age [(56.4±10.1) years vs. (60.0±9.9) years, t=2.838, P=0.005], more distant metastasis and local organ infiltration [25.0%(24/96) vs. 16.1%(71/440), χ 2 =4.246, P=0.039; 64.6% (62/96) vs. 24.5% (108/440), χ 2 =58.331, P=0.000], lower prognostic nutritional index [(48.0±6.7) vs. (50.4±6.9), t=3.093, P=0.002], lower serum hemoglobin level [(115.0±24.7) g/L vs. (127.9±24.6) g/L, t=4.634, P=0.000], lower serum albumin level [(40.0±4.9) g/L vs. (41.2±5.0) g/L, t=2.038, P=0.042], and earlier occurrence of symptoms [(1.9±1.4) months vs. (3.7±3.2) months, t=5.431, P=0.000]. However, there were no statistically significant differences in TNM staging, postoperative hospital stay, and total hospitalization days between the two groups (all P>0.05). During follow-up, 24(25.0%) patients developed recurrence or distant metastasis and 68 (70.8%) patients died of tumor progression in CRS group, while 71(16.1%) patients developed recurrence or distant metastasis and 378(85.9%) patients died of tumor progression in GC group. The 5-year survival rate of CRS patients was 23.4%, which was higher than 15.0% of gastric cancer patients (P=0.032). Univariate analysis showed that the CRS patients with radical operation (P=0.000), earlier TNM stage (P=0.000), non-distant metastasis (P=0.022), serum hemoglobin level >130 g/L(P=0.013), and serum album level >40 g/L (P=0.042) had better prognosis. Multivariate analysis, enrolling above 5 factors, showed that TNM staging (HR=2.363, 95%CI: 1.478-3.776, P=0.000) and serum hemoglobin level >130 g/L(HR=0.449, 95%CI: 0.244-0.827, P=0.010) were independent factors influencing prognosis of CRS patients., Conclusions: Although CRS patients have better prognosis than gastric cancer patients, but local organ invasion and distant metastasis occurs more readily. TNM staging and serum hemoglobin level are independent prognostic factors for CRS patients.

Objective: To develop an up-converting phosphor technology-based lateral-flow (UPT-LF) assay for rapid quantitative detection of Burkholderia pseudomallei on site., Methods: The strip Bps-UPT-LF strip was prepared with up-converting phosphor (UCP) particles as the bio-label using double-antibody sandwich method. Detection performance, including sensitivity, quantitative accuracy, precision, and specificity, were first evaluated using bacterial suspensions of Burkholderia pseudomallei, the related species and the strains which had similar routes of transmission with serial standard concentrations diluted by phosphate buffer, then biological and chemical reagents and simulated samples with series concentrations were employed for sample tolerance evaluation, while the operation error during on site detection was also evaluated through adjusting liquid measure., Results: The whole detection was accomplished within 20 minutes, and the sensitivity was 10(4) CFU/ml with linear quantitative range from 10(4) CFU/ml to 10(7) CFU/ml, which covered four orders of magnitude. Bps-UPT-LF strip demonstrated high specificity with the absence of any false-positive result even at 10(7) and 10(8) CFU/ml of non-specific bacterial contamination. Not only Bps-UPT-LF strip could tolerate to high concentration of the extreme acid and basic matter (pH 1-12), saline matter (≤ 2 mol/L mixture of NaCl and KCl), viscous materials (≤ 50 g/L of PEG 20000 and ≤ 20% of glycerol) and bio-macromolecule (≥ 400 g/L of bovine serum albumin or ≥ 80 g/L of casein), but also it can directly detect animal, environmental and powder specimen, such as ≥ 400 g/L of milk powder, flour powder, fruit juice, fresh and decomposed viscera, and ≤ 200 g/L of putty powder, sucrose, gourmet powder, and soil. Operation errors of liquid measure had few effects on sensitivity and specificity, including -50%-200% of sample, -22%-44% of sample-treating buffer and -30%-30% of loading mixture., Conclusion: The good detection performance and tolerance performance bring the bright future for Bps-UPT-LF strip to detect Burkholderia pseudomallei on site rapidly and quantitatively for nature foci surveillance and anti-bioterrorism.

Objective: To develop an up-converting phosphor technology based lateral flow (UPT-LF) assay for rapid and quantitative detection of Yersinia pestis, Bacillus anthracis spore and Brucella spp.and make the comparison with BioThreat Alert (BTA) test strips (Tetracore Inc., USA)., Methods: Using up-converting phosphor nano-particles (UCP-NPs) as the bio-marker, three double-antibody-sandwich model based UPT-LF strips including Plague-UPT-LF, Anthrax-UPT-LF, Brucella-UPT-LF were prepared and its sensitivity, accuracy, linearity and specificity were determined by detecting 10(10), 10(9), 10(8), 10(7), 10(6), 10(5) and 0 CFU/ml series of concentrations of Y.pestis, B.anthracis, Brucella standards and other 27 kinds of 10(9) CFU/ml series of contrations of bacteria strains.Furthermore, the speed, sensitivity and accuracy of bacteria standards and simulated sample detection were compared between UPT-LF and BTA system., Results: The detection limit of Plague-UPT-LF, Anthrax-UPT-LF and Brucella-LF was 10(5) CFU/ml. The CV of series of bacteria concentrations was ≤ 15%, and the r between lg (T/C-cut-off) and lg (concentration) was 0.996,0.998 and 0.999 (F values were 1 647.57, 743.51 and 1 822.17. All the P values were <0.001), respectively. The specificity of Plague-UPT-LF and Brucella-LF were excellent, while that of Anthrax-UPT-LF was a little bit regretful because of non-specific reaction with two isolates of B. subtilis and one B.cereus. On-site evaluation showed the detection time of UPT-LF for all Y.pestis, B.anthracis spore and Brucella spp.was 33, 36 and 37 min, while BTA was 115, 115 and 111 min, which revealed the higher detection speed and sensitivity of UPT-LF comparing with BTA. The negative rate of two methods for blank standard was both 5/5, the sensitivity of UPT-LF for Y.pestis,B.anthracis spore and Brucella spp. was all 10(5) CFU/ml, then BTA was 10(6), 10(6) and 10(5) CFU/ml, respectively. The detection rate of UPT-LF for all three bacteria analog positive samples was 16/16, while BTA for B.anthracis was 7/16 only., Conclusion: The good performance including rapidness, simplicity and high sensitivity will bring the bright future of UPT-LF to be broadly used on-site as first response to bio-terrorism.

A method was developed for the determination of 20 kinds of pesticide residues in soybeans and corn with the technique of offline disperse solid-phase extraction and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS). The pesticides interested were extracted twice from the samples with acetonitrile. The combined extract was concentrated to dryness and redissolved in acetonitrile, then cleaned up by dispersive solid-phase extraction with sorbents of N-propyl ethylene diamine (PSA), graphited carbon black, and C18, and determined and confirmed by GC-NCI/MS. The recoveries of all pesticides were in the range of 70%-130% at three spiked levels (5, 10 and 20 microg/kg), and the relative standard deviations were below than 17%. The linearity of the method was good in the concentration range of 20-400 microg/L, and limits of quantification (LOQs) were no more than 2 microg/kg. The method is selective well with no interference and suitable for the confirmatory of pesticide residues in soybeans and corn.