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ObjectiveTo investigate the priming effect of mirror therapy combined with task-oriented training on hemiplegic upper limb functions after stroke.MethodsA total of forty eligible inpatients with stroke were divided into observation group and control group according to the random number table method, with 20 cases in each group. The conventional rehabilitation training was used in both groups. The control group was given upper limb task-oriented training 30 min per day in addition to conventional rehabilitation; the observation group was given mirror therapy 30 min per day in addition to the control group, both 5 days per week for 4 consecutive weeks. Assessments were administered at baseline and immediately after all the intervention. The upper limb motor functions were assessed by the Fugl-Meyer assessment-upper extremity (FMA-UE) and action research arm test (ARAT), occupational performance was assessed by the functional test of hemiplegic upper extremity-Hong Kong (FTHUE-HK).ResultsThere were no significant differences in FMA-UE scores, ARAT scores and FTHUE-HK grade between the two groups before treatment (P>0.05). After 4 weeks of treatment, the FMA-UE scores, ARAT scores of the two groups showed significant improvement compared with those before treatment (PPPPP

In order to solve the problem of large deformation of the rocker arm, the virtual prototyping technology is used to soften the front and rear rocker arm, and the dynamic and mechanical model of the shearer is established. The strain gauge data of the picking sensor are obtained, and the load data is obtained by quadratic fitting the actual calibration of the sensor and the data, and the life prediction of the key components is carried out. The results show that the stress value and the load fluctuation value of the rocker joint pin are larger when the flexible deformation of the rocker arm is considered, which indicates that the flexible deformation of the rocker arm increases the vibration impact of the whole machine and reduces the strength of the shearer And the life expectancy of the shearer’s rocker pin, the fatigue life is 1.738×10~6 times, which proves the feasibility of the experimental method and provides the theory for the selection of the rocker pin in the actual working condition.

To study the interaction mechanism of shearer and the surrounding rock,using the MG500/1180-WD shearer model as research objects,EDEM discrete element simulation software is used to establish the three-dimensional simulation model,Considered the effect of the factor which is coal fragmentation and roof pressure on the performance of shearer cutting. Study on the dynamic process of shearer cutting.Using single-factor method to study the effect of coal seam dip angle on the factor of coal loading rate、cutting resistance and special energy consummation for cutting. Study on the wear of cuttings under different working conditions. The results show that when the dip angle is in the range of 0 ° ～ 10 ° in the range of-20 ° ～ 0 °, the effect on the working performance of the shearer is small, which can satisfy the coal loading efficiency of the shearer. Cutting stability. When the absolute value of the dip angle is large, the inclination angle is negative or the absolute value is large, it has a significant effect on the working performance of the shearer. It may be considered to change the working parameters of the shearer, such as reducing the drum speed, Speed, adjust the cutting depth to improve the performance of coal miners, in order to achieve efficient cutting shearer provides an improved reference.

According to shearer vibration problems in the practical work,using multi-body dynamics theory,considering the connection characteristics between walking unit of shearer and scraper conveyor,the support characteristics of adjustment height oil vat,the stiffness of rocker arm of shearer,the connection characteristics between the parts of shearer,vibration angle of shearer,6 degrees of freedom dynamic model in the vertical direction of shearer was established.The vertical direction of shearer drum load was used as an external excitation,and the effect of different coal and rock hardness on vertical direction vibration characteristics of shearer were solved by using numerical analysis method. The results show that the mean of coal cutting impedance has great influence on vibration displacement of front and rear cutting unit when the range is 200 kN/m ～ 400 kN/m,the displacement range of front and rear drum is 13. 42 mm ～ 26. 83 mm、8. 19 mm ～ 16. 37 mm,and the displacement range of front and rear rocker arm is 5. 31 mm ～ 10. 62 mm、3. 32 mm ～ 6. 65 mm.Finally,the results of model is verified by experiment.

Based on the theory of rigid-flex coupled multi-body system dynamics,systematic research has conducted on transmission system of a coal winning machine’s cutting part. By using the software of Recur Dyn,the model was established including transmission gears,drive shaft and bearing. Considering the flexible characteristics of drive shaft,the rigid-flexible coupled model was built.Transmission system of a coal winning machine’s cutting part was simulated dynamics analysis before contact parameter setting on the parts of transmission system. The working process of shearer transmission system was described intuitively and dynamically. Results showed that 11 th gear mesh together is the biggest,11272634. 4 N.4 th. The maximum strain,measured at the axes of 4,is 0. 081. It reveals the difference of Gear meshing force curve and its frequency-domain information between Rigid-flexible coupling system and Stiff systems. Results provide a basis for optimum design of the transmission system and prediction of fatigue life.

According to shearer vibration problems in the practical work,using multi-body dynamics theory,considering the connection characteristics between walking unit of shearer and scraper conveyor,the support characteristics of adjustment height oil vat,the stiffness of rocker arm of shearer,the connection characteristics between the parts of shearer,vibration angle of shearer,6 degrees of freedom dynamic model in the vertical direction of shearer was established.The vertical direction of shearer drum load was used as an external excitation,and the effect of different haulage speed on vertical direction vibration characteristics of shearer were solved by using numerical analysis method.The results show that the haulage speed has great influence on vibration displacement of front and rear cutting unit when the range is 2 m/min～5 m/min,the displacement range of front and rear drum is 12.3325 mm～38.9104 mm、7.5240 mm～23.7396 mm,and the displacement range of front and rear rocker arm is 4.8826 mm～15.4052 mm、3.0548 mm～9.6384 mm.Finally,the results of model is verified by experiment.

According to shearer vibration problems in the practical work,using multi-body dynamics theory,considering shearer support characteristics of guide boots and pin-rail,the friction between flat boots and middle trough,the connection characteristics between the parts of shearer,vibration angle of shearer,6 degrees of freedom dynamic model in the lateral direction of shearer was established. The axial direction of shearer drum load was used as an external excitation,and the effect of different haulage speed on lateral direction vibration characteristics of shearer were solved by using numerical analysis method. The results show that the haulage speed has great influence on vibration displacement of front and rear cutting unit when the range is 2 m/min 5 m/min,the displacement range of front and rear drum is 4. 994 1 mm 11. 262 3 mm、4. 842 0 mm 10. 791 7 mm,and the displacement range of front and rear rocker arm is 3. 199 1 mm 5. 709 7 mm、3. 046 3 mm 5. 236 9 mm. Research results provide the basis for shearer in the actual production process. Finally,the results of model is verified by experiment.

In order to study the fatigue life of the planet carrier in the actual working conditions,through the cutting experiment,the three-force loads was obtained,and the reconstruction function of the three-force load was established. The method of the SOR method was used to solve the reconstruction function. According to the roller structure parameters,the load torque of the planet carrier was performed. Using ANSYS Workbench transient dynamic analysis on the dynamics of the planet carrier,and the torque was loaded in the form of the time series to planet carrier,the results file to import ncode of planet carrier life prediction and simulation results show that: The service life of the output shaft and the side wall panel is small,which shows that the geometrical size of the output shaft is larger,and the stress concentration phenomenon exists.

According to shearer vibration problems in the practical work,using multi-body dynamics theory,considering shearer support characteristics of guide boots and flat boots,and the stiffness of rocker arm and adjustment height oil vat,6 degrees of freedom dynamic model in the vertical direction of shearer was established.The vertical direction of shearer drum load was used as an external excitation,and the effect of different lift angle on vertical direction vibration characteristics of shearer were solved by using numerical analysis method.The results show that the lift angle has great influence on vibration displacement of drum and ranging arm when the range is 17° 37°,and the displacement range is 21.5521 15.424 mm,9.4005 ~3.306 4 mm.Because of the low frequency vibration of shearer under actual operating conditions,the vibration acceleration under different lift angle is insensitive.

By establishing the mechanical model,the analysis study on scraper chain tension variation is carried out,through the MATLAB software,the change rule of scraper chain tension under different working condition is simulated. Through finite element analysis software ANSYS Workbench,the finite element analysis of central trough of scraper chain sunroof open and close two states under load conditions is carried out,the stress concentration and the maximum displacement positions of the condition are determined,it is found that the strength of hanging ear plate is not enough,after the material replacement for Q690,the strength requirement is meet. According to the result of finite element analysis and statics analysis and calculation,by using n Code software,the fatigue strength analysis is carried out on the scraper chain,the life and injury cloud chart are obtained,it in line with the finite element analysis results and can satisfy the requirements of use.

On the basis of the theory of rigid-flexible coupling multibody dynamics as well as the transmission system of coal winning machine cutting part the transmission principle and structure parameters,the dynamic characteristics of coal winning machine cutting part drive system was researched for the problem about dynamic characteristics of coal winning machine cutting part the transmission system. The rigid-flexible coupling dynamics model of coal winning machine cutting part for gear transmission system was built in Recurdyn software environment. To the cutting force in drum three loads,Transmission Model was under full consideration of the flexible drive shaft in all directions feature and calculated the gear meshing force,strain and bearing junctioncontact. Results showed that 11 th gear mesh together is the biggest,11272634. 4N. The maximum contact force,912317. 98 N,is measured at the place of the shaft 5 bearings 1. Results provide a basis for optimum design of the transmission system and prediction of fatigue life.

To research the dynamic character of plough under oblique cut conditions,the cutting coal wall depth of planing tool and the condition of participate in cutting were derived. The dynamic model of plough was established by finite elem ent method. The numerical simulation analysis of dynamic character of plough was executed. velocity and tension fluctuation curve of plow head and chains were obtained. Take feeding velocity and middle trough swing angle as design variables,and take minimal unit energy consumption and minimal load fluctuation rate as objective function. The Optimal design was executed by the method of multi-population genetic algorithm. The results are obtained that the optimal feeding velocity is 1. 2m/s,and middle trough optimal swing angle are 1°,1°,0. 7°. The results provide theoretical basis for coal plough in engineering.

In order to study the influence of shearer traction speed on its dynamic characteristics,using the three-axis force of pick as the description of cutting incentive of shearer pick,Hertz contact theory was used to describe shearer’s smooth boot brace stiffness and damping. Nonlinear model of meshing gear with the clearance was used to describe brace stiffness and damping of shearer guide boot and the pin rows. 7-DOF dynamic model of shearer was established according to Lagrange ’s equations. Vibration characteristics of shearer under different traction speed was solved by numerical methods. The results show that the increasing of speed have great influence on the vibration displacement of back-end drum,have little effect on the fuselage,and have significant influence on Y axis vibration angle of the fuselage.

Objective: To investigate the effect of miR-93/EphA4 (Eph receptor A4) axis on the proliferation and migration of non-small cell lung cancer (NSCLC) H460 and H1299 cells via regulating extracellular regulated protein kinases (ERK) pathway. Methods: The expression levels of miR-93 in H460 and H1299 cells was detected by qPCR. miR-93 mimics and EphA4 overexpression plasmids were transfected into H460 cells and miR-93 inhibitor was transfected into H1299 cells respectively, after which MTT assay and Transwell assay were used to detect the effects of miR-93 on proliferation and migration of transfected cells. The targeted regulatory relationship between miR-93 and EphA4 was verified by Dual-luciferase reporter gene assay. The expression levels of PCNA (proliferating cell nuclear antigen), EphA4, ERK and p-ERK were detected byWestern blotting. The effects of simultaneous overexpression of miR-93 and EphA4 on proliferation and migration of H460 cells were detected by MTT assay and Transwell assay. Results: The expression of miR-93 in H1299 cells was higher than that in H460 cells (P<0.01). Overexpression of miR-93 promoted proliferation and migration of H460 cells (all P<0.01), and knockdown of miR-93 inhibited proliferation and migration of H1299 cells (all P<0.01). The Dual-luciferase reporter gene assay confirmed that miR-93 could target EphA4. Overexpression of miR-93 down-regulated the mRNA and protein expression levels of EphA4 (all P<0.05), and promoted proliferation and migration of H460 cells through targeted regulation of EphA4 and activation of ERK pathway (all P<0.01). Conclusion: miR-93 promotes the proliferation and migration of NSCLC cells, and its mechanism may be related to the targeted regulation of EphA4 and activation of the ERK pathway. [ABSTRACT FROM AUTHOR]

The development and prosperity of the Yuan drama is closely related to the combination of literary and commercial. The prosperity of the drama performance was both the result of drama creation and the strong motivation to promote it development, which has changed to some extent the relations among literature, politics, and economy, and the relationship between the writers and the ruling clique. When the drama creation became the most important part of the art performances, play writers had the space to settle down in the social life, to win economic freedom, and to gain mind liberation and personal independence which be highlighted in their works. Play writers and their works manifested a new look, which was a revolutionary significance for writers' status and literary features, and to some extent to determine the future trend of literary development. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials are widely used in the treatment of water pollutants because of their structural characteristics such as large specific surface area， complex pore structure， and rich surface functional groups. This paper summarized the carbon sources and preparation methods of nanocarbon materials， analyzed the principles and influencing factors of nanostructure regulation of carbon materials， reviewed the research progress in nanocarbon adsorption of toxic pollutants in water， and put forward the bottlenecks that need to be broken through for the future industrial application of nanocarbon materials. Hydrothermal， pyrolysis and chemical vapor deposition are the common methods for the preparation of nanocarbon， and traditional carbon sources， such as sugars， petrochemicals， and biomass， can be used to obtain nanostructured carbon through the modulation of parameters such as preparation temperature and activator. Carbon nanotubes， carbon nanospheres， and nanoporous carbon have been developed for better contact with pollutants， thus exhibiting significant adsorption advantages for toxic pollutants such as phenols， benzenes， dyes， antibiotics， and heavy metal ions. In order to realize the wide application of nanocarbon adsorbent materials， further research is required to be carried out in the future on the development of green and efficient preparation process of nanocarbon， the exploration of the formation and evolution law of carbon structures， the design of macroscopic use scheme of nanocarbon， and the development of nanocarbon based composite materials.

To improve the corrosion resistance of proton exchange membrane fuel cell (PEMFC) bipolar plates，TiC coatings were prepared by atmospheric plasma spraying (APS).The morphology and structure of the coatings were characterized by scanning electron microscopy (SEM)and X-ray diffractometer (XRD).The corrosion resistance of TiC coatings prepared at three different currents in the PEMFC environment was studied by potentiodynamic polarization，potentiostatic polarization and electrochemical impedance spectroscopy (EIS).Results showed that the corrosion current density of the TiC coating was one order of magnitude lower than that of the stainless steel substrate，indicating that the coating could effectively improve the corrosion resistance of 316L stainless steel.With the increase of spraying current，the coating at 500 A was shown to have the best corrosion resistance and conductivity.This was mainly due to the increase in current，which fully melted the particles，increased the density of the coating，and reduced defects such as pores.

In this study, the volatile components and key aroma-active compounds of 13 representative Huiming tea samples were analyzed using stir bar sorptive extraction (SBSE) combined with gas chromatography-olfactometry-mass spectrometry (GC-O-MS). Results showed that a total of 120 volatile components were identified, mainly including 26 alcohols, 26 esters, and 14 ketones. Among them, the contents of the aroma compounds geraniol, 2,2,4-trimethyl-3-hydroxypentyl isobutyrate, indole, (Z)-jasmone, and 1-octen-3-ol were the highest. Moreover, a total of 42 key aroma-active compounds were identified by GC-O analysis, including 2-ethyl-3,5-dimethylpyrazine, 6-methyl-5-heptene-2-one, linalool, (Z)-3-hexenyl butanoate, 3,5-octadiene-2-one, and (E)-β-ionone, which played an important role in the formation of the fresh and floral aromas of Huiming tea. The results of this study will contribute to revealing the chemical basis of the aroma quality of Huiming tea, and provide a theoretical basis for improving the aroma quality of Huiming tea.

The fresh leaves of Kucha No.6 with high theacrine as raw materials in different seasons were processed into green tea, white tea and black tea. The tea suitability of Kucha No.6 was comprehensively analyzed by sensory evaluation and main quality components. The sensory evaluation results showed that three types of Kucha No.6 tea all had different degrees of bitterness (green tea>white tea>black tea), and the bitterness of spring samples was greater than that of other two seasons. Among of them, green tea had a floral and bean fragrance, a mellow and bitter taste. White tea had a medical and floral fragrance, a mellow taste, and black tea had sweet and rich fragrance, mellow and refresh taste. Additionally, the results of main quality components analysis showed that the contents of some components related to bitterness, such as tea polyphenols, total catechins, EGCG, and EGC, were significantly higher in green and white tea than those in black tea. Furthermore, the contents of theacrine in three types of Kucha No.6 tea in spring were significantly higher than those in other two seasons. According to this study, Kucha No.6 containing high theacrine was more suitable for making black tea, not only because the high contents of theacrine, but also of the characteristics of sweet and rich fragrance, mellow and refresh taste. Although green tea and white tea made by Kucha No.6 had strong bitter taste, they were more suitable for promoting as further processed products because of their high contents of healthcare functional ingredients such as theacrine, EGCG, etc. This study provides more theoretical and practical basis for the further development and utilization of Kucha resources.

Green tea was made from one bud with two leaves from the tea cultivar Longjing 43 by stir frying, roasting, steaming or sun drying. Stir bar sorptive extraction (SBSE) combined with gas chromatography-olfactometry-mass spectrometry (GC-O-MS) was applied to analyze the influence of different manufacturing processes on the key aroma-active compounds of green tea. The results showed that 31, 27, 25 and 30 key aroma-active compounds were respectively identified from stir-fried green tea, roasted green tea, steamed green tea and sun-dried green tea, which all had floral, fruity and green flavors. Totally, 13 key aroma-active compounds were common to these 4 types of green tea, including β-ionone, naphthalene, linalool, linalool oxide I, geraniol, 1-octene-3-ol, 2-heptanone, heptanal, hexanal, (Z)-3-hexenyl acetate, (E,E)-2,4-decadienal, α-ionone, and phenylethyl alcohol. It was found that β-ocimene and (Z)-hex-3-enyl 2-methylbutyrate contributed greatly to the aroma characteristics of stir-fried green tea; 2-pentylfuran, phenylacetaldehyde and α-terpineol contributed greatly to the aroma characteristics of roasted green tea; and geranylacetone, γ-terpinene and α-citral contributed greatly to the aroma characteristics of sun-dried green tea. The results obtained from this study will help to understand the formation mechanism of green tea aroma quality and to develop directional processing and regulation technologies for green tea aroma quality.

The accurate estimation of inertia is the premise of analyzing the security and stability of the system frequency, but the existing methods can not quantitatively evaluate the effect of virtual inertia on the equivalent inertia of the power system. In view of this, an inertia estimation method of power system with virtual inertia response of wind power is proposed. Firstly, the theoretical expression of equivalent inertia of power system including virtual inertia response of wind power is derived. Secondly, the phasor measurement unit (PMU) is used to obtain the active power and frequency data at the node of the power generation device. Thirdly, the active power output of the power generation device is taken as the input of the identification model, and the frequency disturbance is taken as the output. Using controlled autoregressive (CAR) model and time-varying forgetting factor recursive least squares (TFF-RLS) algorithm evaluated the equivalent inertia of the whole network under different wind power proportions. Finally, the feasibility and applicability of the proposed method are verified by an improved IEEE-10-machine 39-node system. Compared with the traditional identification method, the accuracy of the inertia estimation of the proposed method is improved, and it is suitable for the time-varying inertia estimation of the new energy power system.

Objective: In this study, Corynebacterium glutamicum ATCC 13032 was used as the chassis cell for synthesizing L-homoserine and analyzing the effect of dissolved oxygen on product synthesis. Methods: First, the product tolerance of C. glutamicum was analyzed by exogenously adding 0~40 g/L L-homoserine. Second, the degradation pathway of L-homoserine was blocked by gene thrB knockout, namely C. glutamicum recombinant strain H1. On this basis, the shake flask with baffles was used for cell culture to enhance oxygen supply capacity in the fermentation process. Results: Compared with Escherichia coli, C. glutamicum had a stronger tolerance to L-homoserine. In the study, C. glutamicum recombinant strain H1 was constructed by deleting the gene thrB. It was found that the growth of recombinant strain H1 returned to normal after adding 0.5 g/L L-threonine in the basal medium. The L-homoserine production of recombinant strain H1 increased to 836.7 mg/L using shake flask with baffles, which was 17.76 times higher than that using ordinary shake flask, which was 44.6 mg/L. Conclusion: C. glutamicum recombinant strain H1 was successfully constructed for producing L-homoserine via blocking the synthesis of L-threonine. It was found that the using of shake flask with baffles to enhance the oxygen supply capacity during fermentation was an effective means to promote the production of L-homoserine by C. glutamicum. This study provides a reference for improving L-homoserine production subsequently.

The study aimed to develop green degradable food packaging materials. Here, the composite film was prepared by tape casting method, which pea starch (PS) was used as the main film-forming matrix, modified corn bract cellulose (MCBC) and nano talcum powder (NTP) were used as reinforcing material and glycerin was used as plasticizer. The properties of the composite membrane were determined, and the composite membrane was characterized by scanning electron microscope and Fourier infrared spectroscopy. Finally, the thermogravimetric analysis and degradation analysis were carried out. Results showed that, the optimal preparation conditions of composite film including PS 8%, glycerol 2.5%, MCBC 0.8%, NTP 0.15% by using the method of single factor experiments and orthogonal experiment. Under these conditions, the thickness of composite film was 0.042 mm, the transmittance was 32.58%, the tensile strength was 32.48 MPa, the elongation at break was 33.61%, the water vapor transmission was 0.19×10−10 g/(m·s·Pa), the oil permeability coefficient was 0.006 g·mm/m2d, the water absorption rate was 55.79% and the solubility was 18.04%. The results of scanning electron microscopy (SEM) showed that the surface of the composite film was smooth and uniform, and the structure was compact. The results of fourier transform infrared spectroscopy (FTIR) showed that MCBC, NTP and PS were compatible well, and the intermolecular hydrogen bond of them were enhanced. Moreover, the results of thermal gravimetric analyzer (TGA) showed that the decomposition temperature of composite film was 318.12 ℃, and the heat stability of composite film was improved. Degradation analysis also showed that the natural degradation rate of composite film was 96.47% after being buried in soil for 8 days, therefore, the composite film could be biodegraded completely. The study would provide a reference for the application of MCBC/NTP/PS composite film in food industry.

Background Noninvasive positive pressure ventilation (NPPV) is the most common treatment for obstructive sleep apnea hypopnea syndrome (OSAHS) , which can effectively improve the hypopnea condition. At present, there are various NPPV programs with no summary of the relevant best evidence in China. Objective To search and evaluate studies related to NPPV management in OSAHS patients, then summarize the best evidence, to inform clinical practice. Methods All evidence (including guideline, expert consensus, randomized controlled trial, evidence summary, systematic evaluation and meta-analysis) on the management of NPPV in patients with OSAHS was retrieved from databases and websites including BMJ Best Practice, Up To Date, Scottish Intercollegiate Guidelines Network, Guidelines International Network, National Institute for Health and Care Excellence, National Guideline Clearinghouse, Registered Nurses' Association of Ontario, New Zealand Guidelines Group, Chinese Guideline Network, the Joanna Briggs Institute Evidence-based Health Care Center, Cochrane Library, Web of Science, Embase, PubMed, Scopus, Wanfang Data, CNKI, VIP and American Academy of Sleep Medicine from inception to December, 2021. The methodological quality of the included literature was evaluated using corresponding quality evaluation criteria. The evidence was described and summarized using JBI levels of evidenceand and JBI grades of recommendation (2014) , then the recommended strength of the evidence is determined according to the FAME scale (feasibility, appropriateness, meaningfulness and effectiveness) . Results A total of 10 studies were included, including 6 guidelines, 2 expert consensuses, 1 Meta-analysis and 1 randomized controlled trial. Finally, 27 pieces of best evidence were summarized, involving 8 aspects: scope of application, duration of use, mode selection, pressure regulation, efficacy evaluation, nursing intervention, follow-up and alternative treatment. Conclusion We summarized the best evidence involving the above-mentioned 8 aspects for NPPV management in OSAHS patients, providing an evidence-based basis for the implementation of standardized NPPV treatment.

Three purple tea varieties (lines), namely Hongye-1, Hongye-2, Danfei in different seasons as test materials, were made into green tea, white tea and black tea. And we assessed the suitability of purple tea varieties (lines) by tea quality analysis and sensory evaluation. The results showed that the contents of physical and chemical contents were higher in green teas and white teas than in black teas. The green teas had the highest physical and chemical contents, which had the average content of 4.24% to 4.69% in soluble sugar in three seasons; while the black teas were 3.54% to 3.96%. Amino acid contents in white teas were higher than in green teas and black teas, which was above 3.40% in white tea; while in black tea and green tea amino acid contents were about 3%. Green teas made with purple tea had the highest content of anthocyanins in summer, second in autumn and lowest in spring. Anthocyanin contents in green teas were 0.086% to 0.115% in summer. In addition to the trace anthocyanins detected in spring white tea, neither white tea nor black tea were detected with anthocyanins in different seasons. Sensory evaluation showed that the white teas made from the purple tea were rich in elegant floral or fruit aroma, with sweet and mellow tastes; the black tea had the characteristics of rich sweetness aroma, sweet and fresh taste; and the green tea retained more quality components, and had reddish violet soup color. Therefore, purple tea was more suitable to be made into black tea and white tea; and green tea could be popularized as a new special tea drink. This study provides a theoretical and practical basis for the further use of purple tea.

The response surface methodology was employed to optimize the process conditions of Gluconobacter frateurii for producing glycolic acid. First, single factor test and Plackett-Burman test design were used to screen out the three main factors affecting the production of glycolic acid: Sorbitol concentration, yeast powder concentration, and ethylene glycol concentration. On this basis, the steepest climbing path method was used to approach the maximum response value range, and the response surface methodology was used to determine the interaction and optimal conditions between these main factors. The results showed that the optimization concentration were: Sorbitol 40.30 g/L, yeast powder 36.90 g/L, CaCO3 2.50 g/L, ethylene glycol 28.14 g/L, culture temperature 30 °C, pH7, inoculum size 10% (v/v), rotating speed 200 r/min, fermentation period 48 h. Under the optimized condition, the titer of glycolic acid reached 21.04 g/L. After three parallel experiments, the actual average titer was close to the predicted titer. The conversion rate of glycolic acid was increased by 28.25%, reaching 74.77%, and the productivity was 10.52 g/(L·d).