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Saccharomycopsis fibuligera, also known as Endomyces fibuliger or Saccharomyces fibuligera, is a yeast that produces ascospores and is widely found in all types of fermentation starters. It secretes α-amylase, β-glucosidase and acid protease with high efficiency and is an important functional microorganism in the fermentation of grains. Hence, S. fibuligera has high industrial application value; for example, it has a high starch conversion capacity and can synthesise trehalose from starch and it can decompose and synthesise single-cell proteins from starch and use proteins as a protein feed. It also produces aromas, esters and alcohols via fermentation; thereby, improving liquor quality. Moreover, S. fibuligera exerts an inhibitory effect on guava grey mould and can synthesise fungicides. Because S. fibuligera has excellent development potential and research value in industrial production, it has attracted considerable attention. In this study, the physicochemical, enzymatic and ester-producing properties of S. fibuligera and its effect on liquor flavour were examined. These findings will help screen excellent strains, optimise liquor fermentation conditions and improve liquor production quality.

Clostridium butyricum is an anaerobic bacterium that inhabits broad niches. Clostridium butyricum is known for its production of butyrate, 1,3-propanediol, and hydrogen. This study aimed to present a comparative pangenome analysis of 24 strains isolated from different niches. We sequenced and annotated the genome of C. butyricum 3-3 isolated from the Chinese baijiu ecosystem. The pangenome of C. butyricum was open. The core genome, accessory genome, and strain-specific genes comprised 1011, 4543, and 1473 genes, respectively. In the core genome, Carbohydrate metabolism was the largest category, and genes in the biosynthetic pathway of butyrate and glycerol metabolism were conserved (in the core or soft-core genome). Furthermore, the 1,3-propanediol operon existed in 20 strains. In the accessory genome, numerous mobile genetic elements belonging to the Replication, recombination, and repair (L) category were identified. In addition, genome islands were identified in all 24 strains, ranging from 2 (strain KNU-L09) to 53 (strain SU1), and phage sequences were found in 17 of the 24 strains. This study provides an important genomic framework that could pave the way for the exploration of C. butyricum and future studies on the genetic diversification of C. butyricum.

Chinese traditional liquor, a major type of global distilled spirits, offers a unique flavor system acquired across thousands of years of development. Owing to the various raw brewing materials, types of koji, fermentation vessels, and processes used during liquor production, significant differences can occur in the content of flavor chemical components, such as esters, alcohols, aromatics, ketones, nitrogen compounds, acids, and aldehydes in the resulting liquor. Therefore, the liquor can be characterized on the basis of four basic flavors: sauce-, strong-, light-, and rice-aroma, and eight derivative flavors: feng-, sesame-, chi-, te-, mixed-, laobaigan-, herbal-, and fuyu-aroma. In this review, we describe the production and development process of Chinese traditional liquor in detail; summarize the flavor types, flavor chemical composition characteristics, and research progress related to this liquor; and discuss the influence of trace chemical components on liquor flavor, with the aim of laying a theoretical foundation for stabilizing the quality and increasing the yield of traditional liquor.

"AIM: To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography (RP-HPLC), and to evaluate the retinal neuroprotective effect after topical administration with moxonidine in a high intraocular pressure (IOP) model. METHODS: The eyes of albino rabbits were administered topically and ipsilaterally with 0.2% moxonidine. A RP-HPLC method was employed for the identification and quantification of moxonidine between 2 and 480min, which presented in the aqueous humor and iris-ciliary body. Flash electroretinography (F-ERG) amplitude and superoxide dismutase (SOD) level were measured between day 1 and day 15 after topical administration with moxonidine in a rabbit model of high IOP. Histological and ultrastructural observation underwent to analyze the changes of retinal morphology, the inner retinal layers (IRL) thickness, and retinal ganglion cell (RGC) counting. RESULTS: Moxonidine was detectable between 2 and 480min after administration, and the peak concentration developed both in the two tissues at 30min, 0.51 µg/mL in aqueous humor and 1.03 µg/g in iris-ciliary body. In comparison to control, F-ERG b-wave amplitude in moxonidine eyes were significantly differences between day 3 and day 15 (P

Clostridium beijerinckii is a well-known anaerobic solventogenic bacterium which inhabits a wide range of different niches. Previously, we isolated five butyrate-producing C. beijerinckii strains from pit mud (PM) of strong-flavor baijiu (SFB) ecosystems. Genome annotation of the five strains showed that they could assimilate various carbon sources as well as ammonium to produce acetate, butyrate, lactate, hydrogen, and esters but did not produce the undesirable flavors isopropanol and acetone, making them useful for further exploration in SFB production. Our analysis of the genomes of an additional 233 C. beijerinckii strains revealed an open pangenome based on current sampling and will likely change with additional genomes. The core genome, accessory genome, and strain-specific genes comprised 1567, 8851, and 2154 genes, respectively. A total of 298 genes were found only in the five C. beijerinckii strains from PM, among which only 77 genes were assigned to Clusters of Orthologous Genes categories. In addition, 15 transposase and 12 phage integrase families were found in all five C. beijerinckii strains from PM. Between 18 and 21 genome islands were predicted for the five C. beijerinckii genomes. The existence of a large number of mobile genetic elements indicated that the genomes of the five C. beijerinckii strains evolved with the loss or insertion of DNA fragments in the PM of SFB ecosystems. This study presents a genomic framework of C. beijerinckii strains from PM that could be used for genetic diversification studies and further exploration of these strains.

Chinese rice wine (CRW) is an ancient wine with a moderate alcohol content; it has been prized in China for its color, sweet flavor profile, and is a national beverage typically used in banquets. Wheat Qu is the starter used to make CRW, and plays a vital role in the quality and flavor profile. This review details the raw materials and the wheat Qu manufacturing process, and recent information on wheat Qu microbiotas. The volatile compounds in wheat Qus and its flavor are also reviewed. Finally, the enzymes, and metabolites contained in wheat Qu, such as biogenic amines, are also discussed.

Chinese baijiu is produced using a unique brewing method, and few studies have examined changes in microbial communities during baijiu fermentation. In this study, changes were evaluated in...

Xiaoqu liquor is a type of distilled spirit in China prepared on a small scale from a small solid starter culture. Although this liquor is popular in southwestern China, it can have a dull taste, limiting its market. To improve the flavour profile of Xiaoqu liquor, we selected two functional yeast strains (Saccharomycopsis fibuligera and Saccharomyces cerevisiae) from Zaopei (fermented grain) of Baijiu liquor and used them for Xiaoqu liquor fermentation. Compared with traditional Xiaoqu (Starter), bioaugmentation inoculation increased the glucoamylase and acidic protease activities and the ethanol synthesis rate, while decreasing the acidity of the Zaopei (fermented grains) in the early stage of fermentation. By the end of the fermentation process, the alcohol and ester content had also increased by 42.5% and 11.8%, respective, and that of aldehydes and ketones, and heterocyclic compounds decreased by 73.7% and 77.1%, respectively. Traditional isolation and high-throughput sequencing were employed to analyse the microorganisms in the Zaopei. Bioaugmentation inoculation increased the microbial diversity of Xiaoqu liquor during the fermentation process. The dominant fungus during fermentation using the two types of starter cultures was S. cerevisiae, whereas the dominant bacteria was Pseudomonas, followed by Bacillus, Weissella, Lactobacillus, and Bacteroides. Principal component analysis of the bacterial community structure and flavour substances in the Zaopei produced using the two strains revealed that there were few differences between the two liquors and that inoculation with functional yeasts may not change the flavour substances in Xiaoqu liquor. However, correlation analysis showed that Escherichia Shigella, Terrisporobacter, Bacillus, Clostridium, and Prevotellaceae are the main microorganisms in the Xiaoqu liquor fermentation process. These results lay the foundation to improve the quality of Xiaoqu liquor.

Fen-flavor liquor is one of the three basic types of Chinese liquors and can be classified into Daqu, Fuqu and Xiaoqu light-flavor Chinese liquors based on the raw materials used as fermentation starter. The characteristic flavor and taste of Fen-flavor liquor is attributed to its different aromatic components. This study compares the production process and characteristics of Daqu, Fuqu and Xiaoqu Fen-flavor liquors. We review the current research status on aroma compounds and developmental trends in light-flavor Chinese liquors to provide a basis for further studies on the flavor compounds in different types of Chinese liquors.

Yeast, bacterial, and mold strains in different stages during the daqubased production of Luzhou-flavored liquor were isolated and identified by analyzing the 26S rRNA, 16S rRNA, and internal trans...

Varnish is a kind of fouling adhered on bearing inner face near the load zone. The model to analyze its influence on bearing performance and rotor vibration was set up. Pressure and temperature distribution were solved on the basis of the Reynolds equation by the iteration method simultaneously. It is found that bearing performance is changed by the step flow effect at the leading edge of the varnish. Its influence is more obvious when the rotating speed is low. Bearing varnish results in a large decrease of minimum clearance and an increase in the oil film temperature and pressure. Loading capacity of bearing is also decreased. It is harmful to the bearing. With the varnish, the minimum oil film thickness decreases. This leads to an increase of bearing stiffness and damping coefficients. Its influence is larger in the horizontal direction than that in the vertical direction. The trend of unbalance response to rotating speed is similar. There is little influence of the varnish on the modal frequency. However, system stability is improved due to the increased bearing damping coefficients.

To confirm the most correct method between different analysis methods used in the activity analysis of glucoamylase of Koji, the analysis result by several methods used commonly were compared in this study. It is showed that results were quite different between different measurement methods. Glucoamylase activity in Koji by white spirit method was 36~200 u/g; it was 144.98~318.95 u/g by the method of national standard of China (GB), it was 26.96~146.67 u/g by the DSN method, it was 392.04~419 u/g by Japanese Sake Koji analysis method. It was particularly evident in the sample amount for GB; results by enzymes extraction at 30°C were greater than that at 40°C. By different enzyme extraction methods, the result show that, the activity with the extraction method in sake was greater than that with other two extraction methods of GB and DSN. By different measurement methods, but using same extraction method, the result show measurement methods in several assays had some adaptability. In shortly, glucoamylase activity by the method used in Sake was the most stable, best embodying. Activity of glucoamylase by the extraction method (by dialysis), measuring with DNS measurement method, the results were relatively stable, closest to it.

Maotai-flavor liquor is one of the three basic traditional Chinese baijiu and is also the most famous baijiu in the world. Guizhou Maotai baijiu is the representative of Maotai-flavor liquor, which has a long history of culture and is prepared using unique brewing methods. However, the main flavor of Maotai-flavor liquor as well as the mechanism by which its aroma is produced is unclear. In this review, the Da-qu production and fermentation processes for Maotai-flavor liquor are briefly described along with the flavoring constituents of Maotai-flavor liquor that have been recently reported. In addition, the volatile compounds and the aroma derived from Maotai-flavor liquor are discussed. Finally, the microorganisms for the high-temperature Daqu and fermentation processes of Maotai-flavor liquor are discussed. PRACTICAL APPLICATION: Maotai is one of the most famous baijiu in China and the most valuable in the market. However, it is unclear what is the key flavor of Maotai and what microbial metabolism is produced. So, if we can figure out the key flavor substances of Maotai baijiu, we can use the various technology to explore the microbes that produce this flavor to understand the mechanism of the production of Maotai. This will not only achieve breakthroughs in academic value, but also bring higher value to Maotai. On this basis, we can brew Maotai baijiu with better quality according to the fermentation mechanism of Maotai.

Low alcohol hulless barley wine (HW) is a popular beverage among the highland areas in China. It is known to have several health benefits due to the presence of β-glucan and antioxidant compounds. Therefore, the total β-glucan content, total phenols and flavonoids of HW samples from the highland areas of Sichuan province and Tibet were determined in this study. The results indicated that HW is abundant in both β-glucan (54–76 mg/L) and phenolic compounds (131–178 mg/L). Moreover, this study also investigated the flavor and aroma characteristics of HW samples. A total of forty six volatile aroma substances were identified by GC-MS. The HWs could be classified into three distinct groups in terms of the region of origin according to the results of PCA based on the GC-MS data. These findings provide a useful foundation for further study of the health benefits and the flavor characteristics of HW in highland areas.

Commercially available Sichuan Xiaoqu Liquor of Chongqing Jiangjin, Chongqing Yongchuan, Sichuan Kaijiang, Sichuan Zigong were studied in this experiment. Gas Chromatography (GC) with direct injection was used for analysis on main aromatic components i.g., fusel oil (advanced alcohol), ethyl acetate, etc. The results showed that chromatogram with the similar peaks and kinds of aromatic components in four samples. And the highest among all aromatic components in Xiaoqu Liquor samples of Chongqing Jiangjin, Chongqing Yongchuan, Sichuan Kaijiang were isoamyl alcohol. The concentrations in these saples were 99.53 mg/100 mL, 117.01 mg/100 mL, 77.21 mg/100 mL, respectively. But the highest in the liquor of Sichuan Zigong was the ethyl acetate, mass concentration was up to 208.08 mg/100 mL. Isoamyl alcohol and normal propyl alcohol had close quantity relative ratio relationships in four samples, the ratio respectively were 1.0, 1.2, 1.1, 1.5, isoamyl alcohol and isobutyl alcohol ratio were 2.5, 1.8, 2.2, 2.4, respectively. Special ratio relationships among fusel oil can be used as a sign of Sichuan Xiaoqu Liquor. The main aromatic components of recovery test results was 82.09-116.53%, Relative Standard Deviation (RSD) was 1.23-6.88%. The method had fine accuracy and precision and suitable for quantitative analysis of aromatic constituents of Sichuan Xiaoqu Liquor.

The free radical scavenging ability of fullerenols is their most exploited property in biomedical studies. The antioxidant properties and associated mechanisms of fullerenol have been previously investigated, but less research has been done to examine the hepatoprotective effects of fullerenol nanoparticles on alcohol-induced oxidative stress. This study examined the antioxidant effects in rat liver primary hepatocyte exposure to fullerenols dissolved in ethanol. In this study, liver primary hepatocytes of Wistar rats were divided into nine experimental groups that were exposed to ethanol (0.1, 1.0 and 10%), fullerenol dissolved in ethanol (0.1, 1.0 and 10%) and controls (PBS; PBS + fullerenol; Vitamin C (Vc) in 10% ethanol). The results demonstrated that fullerenol nanoparticles in 400 μmol L−1 exhibited excellent ROS scavenging abilities. This contributed to the anti-inflammatory effects involving reduced alcoholic oxidative damage and the regulated promotion of the tumor necrosis factor. The intracorporeal metabolism of rat-intake fullerenol was also evaluated by examining precision-cut rat slices of liver and kidney. All results demonstrated the potential hepatoprotective effects of fullerenol nanoparticles in the preventive treatment of alcoholic hepatopathy.

In this study, the effects of low temperature on the quality of 11 kinds of curciferae vegetables cultivated in autumn with different sowing date in Niigata of Japan was studied by evaluating the ascorbic acid, nitrate nitrogen and sugar content. The results showed that vegetables sown at Oct. 28 tended to higher sugar concentration, higher ascorbic acid content and lower nitrate nitrogen content in their leaves than that sown at the date of Sep. 7 and 28. It is indicated that changing the sowing date can improve the quality of vegetable by the low air temperature. The results also showed that it is possible to cultivated vegetables in autumn in Niigata prefecture of Japan, especially for chingensai and serihon.

On the basis of single-factor test, we conducted optimization study on the three major factors (material moisture content, cultivation time, temperature) that affect the production of purebred Monascus spores through orthogonal trial. The results show that, in the trial-level range, moisture content of materials and cultivation time have larger effect on the test results, while the cultivation temperature has little effect. The optimum conditions in preparation of purebred Monascus seed koji are: 60% moisture content of materials, 5 d cultivation time, 35°C cultivation temperature, 0.1 mL inoculation, 10 g filling and 0.2% lactic acid. To verify this test scheme, ultimately the number of spores produced by Monascus is 3.35×10^7/g.

Effects of different airing way of fermented grains on the physical and chemical indicators, uniformity, of unfermented grain and pits fermentation of Luzhou-flavor liquor were studied in this study. The results indicated that as the way of mechanization airing, the machine airing way absolutely more meets the technology demand on the production of Luzhou-flavor liquor than the airing on-field and airing on-bed. Furthermore, it not only benefits for the stability and uniformity of fermented grains, fermenting, but raises productivity of liquor.

Airing on-field, airing on-bed and airing on-machine are the usual way on production of Luzhou-flavor liquor. The essay makes a brief introduction about the three airing ways, at the same time it researches the effect of different airing ways on fermented grains and pits fermentation. As the way of mechanization airing, the machine of airing absolutely meets the technology demand on the production of Luzhou-flavor liquor, moreover, it has saved labor. Furthermore, it not only benefits for the stability and uniformity of fermented grains, fermenting, but raises productivity of liquor.

The two acetyl monoxime colorimetric method was used to detect urea content. The yeast growth curve shows that a large amount of urea in the extracellular is secreted during the growth processing. And in the stable phase (cultured for 51 hours), urea concentration is up to 38.642 mg / L, but intracellular urea concentration (cultured for 27 hours) is only 6.043 mg / L. At same time, the extracellular urea amount secreted in the medium at initial pH3-4 is less than it at initial pH5 treatment. The urea secretion level is lower when yeast cultured in the medium with 12% of alcohol. The extracellular urea level decrease when the culture temperature increased from 28°C to 32°C.

The homogeneous was used to optimize the processing technology of Aspergillus oryzae seed koji. The results show that the culture time is the most significant factor and the sequence of the residual factors are the square of culture time, the interaction between temperature and the time, the interaction of time and wood ash addition, the square of wood ash addition and the inoculation quantity. The results reveal that the optimized culture conditions are proved to be that the incubation time is 9 days, the inoculation quantity is 0.1×107/g, the dosage of wood ash is 1.267% and the culture temperature is 40°C. Under this condition, the prospective spore number of seed koji has reached to 1.89×109 /g.

The concentration of urea generated by Huangjiu yeast at the different conditions was measured with diacetyl oxime colorimetric method. The results show that the production of urea generated by yeast in fermentation process is different from culture conditions. The level of urea of control group is higher than the levels in other conditions. The urea concentration in culture medium presents increasing in the early growth stage and then decreasing in the later growth stage.

Effects of inoculation quantity, culture temperature and time on glucoamylase activity and the optimum conditions of koji-making of Aspergillus oryzae was studied by using single factor and response surface experiment. The results show that 3 factors can significantly impact on glucoamylase activity of koji. The best process condition of koji-making obtained by using the "Design-Expert" software is: culture temperature 38.70 °C, inoculation quantity 0.85 , and culture time 50.47 h.

This study presents an improved impedance method based on unbalanced synchronous excitation to identify the rotordynamic coefficients of labyrinth seals. The rotordynamic coefficient test is implemented near the cylinder resonance frequency to enlarge the influence of seal force. The force generated by the rotor unbalance is used to provide synchronous frequency excitation for the rotordynamic coefficient test. Four unique equations are set up under two sets of different rotor unbalance conditions to obtain four unknown complex rotordynamic coefficients. The factors that influence the rotordynamic coefficients of seals, namely, unbalance mass, inlet/outlet pressure ratio, and rotating speed, are considered. The dynamic coefficients are minimally affected by different rotor unbalances. The direct items are nearly equal with same signs, whereas the cross-coupled items are nearly equal with opposite signs. All coefficients increase with increasing inlet/outlet pressure ratio and rotating speed. The direct stiffness coefficients increase more quickly than the cross-coupled items. In addition, the effect stiffness and effect damping coefficients are analyzed; results indicate that both coefficients increase with increasing rotating speed.

To minimize fluid leakage and improve rotordynamic stability of traditional seals, a new kind of radial annular seal is presented in this article. The structure and the sealing principle are analyzed. Compared to the traditional labyrinth seal, the fluid leakage direction is altered from the axial to radial direction. The flow resistance is increased, and the flow-induced force is reduced greatly. There is also a tremendous improvement in the wear resistance of the seal. Three-dimensional numerical models of the traditional labyrinth seal and radial annular seal are set up. Calculated results show that the discharge coefficient of the radial annular seal is about 20% lower than that of the labyrinth seal. Though the rotating speed has a small influence on the radial seal force for both the radial annular seal and labyrinth seal, it has a large effect on the tangential seal force. The tangential seal force increases with the increasing speed, and the destabilizing force in the radial annular seal is reduced greatly when compared to that in the labyrinth seal. The radial seal force of the radial annular seal is about 1.5–2.5 times as strong as that of the labyrinth seal. The tangential seal force is about 30–50% lower than that of the labyrinth seal under the same eccentricity, and this ratio becomes larger and larger with the increasing speed. Finally, the dependency of the seal characteristics on the design parameters is studied. It is shown that the optimum ratios of the clearance s to the tooth thickness b ( s/ b) for the outward and inward flows are 4.5–5.5 and 11–13, respectively. The flow characteristics perform best with the ratio of the seal chamber width B to the tooth height H ( B/ H) on the same order of 5.5–7 for the two kinds of flows.

AIM: To evaluate the morphological changes in anterior segment in Chinese patients with uveal effusion (UE) after the attack of acute primary angle-closure (APAC) using ultrasound biomicroscopy (UBM), and to assess the clinical course and prognosis of the disease. METHODS: In a retrospective case series, 26 eyes in 26 consecutive patients diagnosed with UE after the treatment of intraocular pressure (IOP)-lowering medication for the attack of APAC were enrolled. The unaffected fellow eyes served as controls. The morphological changes were observed by ultrasonography, slit lamp microscopy and gonioscopy. UBM was used to assess the degree and extent of effusion based on the analysis of parameters associated with UE. RESULTS: The mean IOP was 9.2 (SD 2.1) mm Hg at the diagnosis of UE after IOP-lowering medication, while 14.1 (SD, 2.6) mm Hg in the fellow eyes (P=0.000). The anterior chamber depth (ACD) (P=0.000), angle opening distance at 500 μm (AOD500) (P

Arsenite and arsenate speciation was performed in 121 commercially purchased samples of 12 rice types to understand their relative relevance in rice grain. General effectiveness of a recently developed extraction protocol based on 0.28 M nitric acid at 95 °C was verified by checking the recovery of total grain arsenic and by comparing arsenic speciation in NIST-CRM-1568a, NMIJ-CRM-7503a and IMEP-107 with certificated and literature values. The arsenic speciation highlights the predominance of arsenite in 115 and dimethylarsinic acid in six samples and common minor components including arsenate, monomethylarsonic acid and two unknown arsenical species. Our data also indicate potential influences of other trace elements on As speciation in rice grain. Averagely, arsenite accounts for 90% of inorganic grain arsenic regardless of geographic origin, rice type, grain size, cultural practice and polish treatment. The high arsenite predominance indicates an elevated toxic effect of arsenic in rice than is perceived to date.

The seal force is an important factor in turbomachineries. Therefore, the current paper puts forward an expanded seal force identification model. A seal test rig consisting of several sets of seals was prepared. Using the double-plane unbalance force identification theory in rotordynamics, the distributed seal force in the cylinder became equivalent to two selected planes. Considering the complex cylinder vibration with increasing rotating speed and inlet pressure, the cylinder was regarded as a vibration system with 4 degrees of freedom. The 4×4 impedance matrix was tested at the two selected planes using a shaker in two orthogonal directions. The equivalent seal force can be obtained by multiplying the impedance matrix with the measured change in the cylinder vibration. In the seal rig, tests were performed on the influence of inlet pressure, rotating speed, eccentricity ratio, rotor vibration, and clearance. The seal force increases almost linearly with the increasing inlet pressure, eccentricity ratio, and vibration amplitude. Furthermore, the seal force is strongly sensitive to the change in clearance between the cylinder and the rotating rotor. The phase difference between the seal force and the vibration influences the work done. If the phase difference is nearly 90°, then the work is at maximum. Moreover, the seal force applies positive force on the cylinder and negative force on the rotor.

This paper sets up a dynamic analysis model for cylinder-seal system. A new identification method for fluid-induced force and stiffness coefficients in eccentric seal is presented. The study shows that the system stability decreases with increasing cross-coupled stiffness in a certain range. Beyond this range, the system will be destabilized. Influences of rotating speed, inlet pressure, eccentricity and clearance on fluid-induced force were tested in the rig. It was found that a large tangential fluid-induced force was produced in the direction perpendicular to the eccentric displacement of rotor. The difference between the tangential and radial fluid-induced force became larger and larger with the increasing rotating speeds. Under the action of the seal force, the logarithmic decrement descended with increasing rotating speeds, and the stability of the system decreased. These effects became more and more serious for higher inlet pressure and tighter clearance.

The paper sets up an upwind local differential quadrature-Lagrange interpolation (DQ-Lagrange) method for solving the flow field in the interlocking labyrinth seal. The implementation of the Dirichlet boundary condition and the Neumann boundary condition is improved. The paper analyzes the influence of support domain size, the implementation of boundary condition and the upwind scheme on the accuracy of the calculation. Numerical simulation result shows that the high order Lagrange interpolation may cause numerical oscillation and the local differential quadrature method is recommended. The upwind support domain can improve the accuracy of the calculation. Solution accuracy may be better in case of that the velocity support domain is larger than the pressure support domain.

This paper presents a new rotordynamic measurements conducted on a test rig for evaluation of multiple rings of labyrinth seals. Considering the tilting motion of cylinder occurs in experiments, the impedance matrix of cylinder system is obtained first. An equivalent seal force identification model is set up for multiple seals based on double plane balance theory of rotor dynamics. The resultant seal forces are calculated on two end planes of the cylinder, and resolved to multiple sections that seals located. A frequency domain identification method delivers the test seals stiffness and damping coefficients. Compressed air inlet tests were run from 1000 rpm-2200rpm, 0.1-0.6Mpa supply pressures were used. For each ΔP test condition, the static eccentricity ratio ε=e/Cr is range from zero to approximately 0.6. Results show that 8 rotordynamic coefficients increase almost linearly with inlet/outlet pressure ratio. Increasing eccentricity ratio weakens the stability of seal-rotor system obviously.