NATURE AND CATALYTIC PERFORMANCE OF PtSAPO-5 MOLECULAR SIEVE CATALYST SYNTHESIZED BY ONE STEP

Xiao, Tian cun,Wang, Hai tao,Lu, Yu li,An, Li dun,Wang, Hong li 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5

Pt catalysts supported on silicoaluminophosphate molecular sieves were synthesized by adding platinum salts directly to the gel mixture of SAPO. The synthesized products were marked as PtSAPO-5, in order to distinguish with the SAPO-5 supported platinum catalyst prepared by impregnation, which was marked as Pt/SAPO-5. The as-synthesized and calcined PtSAPO-5 samples were characterized by XRD, ^(29)Si MAS NMR, ^(129)Xe NMR and NH₃-TPD, and their catalytic activities were evaluated by the, hydroisomerization of n-hexane. The results revealed that in PtSAPO-5, the platinum could catalyze the removal of the templates entrapped in the as-synthesized samples. The presence of Pt in the gel mixture can increase silicon content in the framework of SAPO-5, and the acid sites. In the activated PtSAPO-5 catalyst, Pt was highly dispersed in the channel of SAPO-5 molecular sieve. Pt exists in the form of big particles outside of the channel of Pt/SAPO-5 prepared by impregnating method, and impregnation with H₂PtCl_6 improved the strength of acid sites. PtSAPO-5 has a higher activity and selectivity than Pk/SAPO-5 in the hydroisomerization of n-hexane. This is because the former has medium acid sites and high dispersion of Pt, while the channel of Pt/SAPO-5 is somewhat retarded by the big platinum particles, and the acid sites are stronger than the former.

Precision Control and Compensation of Helical Gear Hobbing via Electronic Gearbox Cross-Coupling Controller

Xiao-Qing Tian,Jiang Han,Lian Xia 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The gear generation process is strongly dependent on the accuracy of the multi-axis relative motion, which is controlled by theelectronic gearbox (EGB). This research mainly focuses on helical gear hobbing and on EGB control error analysis, estimation andcompensation in the generation process of a gear hobbing machine. First, a simple approach for estimation of the helical gear pitcherror and the spiral line contour error is proposed. Then, in conjunction with this estimation method, an EGB cross-couplingcontroller (ECCC) architecture, which is connected by the EGB and the cross-coupling controller, is presented. Simulation resultsshow that the proposed ECCC has higher control accuracy than an uncoupled controller, and its control accuracy can be furtherimproved using friction compensation. Finally, experiments are conducted on an YS3118 six-axis hobbing machine. The helical gearsmachined using this machine have high precision. In addition, the proposed ECCC architecture can be implemented easily on mostmotion systems that are in current use.

On the rates of the almost sure convergence for self-normalized law of the iterated logarithm

Tian-Xiao Pang 대한수학회 2011 대한수학회보 Vol.48 No.6

Let {X_i, i≥ 1} be a sequence of i.i.d. nondegenerate random variables which is in the domain of attraction of the normal law with mean zero and possibly infinite variance. Denote S_n=[수식]=max_(1≤ i≤ n)|S_i| and [수식]=[수식]. Then for d>-1, we showed that under some regularity conditions, [수식]=[수식]holds in this paper, where I{ · } denotes the indicator function.

Stereo-digital image correlation in the behavior investigation of CFRP-steel composite members

Xiao-Yuan He,Yun-Tong Dai,Hai-Tao Wang,Tian-Yuan Ge,Gang Wu,Jian-Xiao Wan,Shuang-Yin Cao,Fu-Jun Yang 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.23 No.6

The application of carbon fiber reinforced polymer (CFRP) in steel structures primarily includes two categories, i.e., the bond-critical application and the contact-critical application. Debonding failure and buckling failure are the main failure modes for these two applications. Conventional electrometric techniques may not provide precise results because of the limitations associated with single-point contact measurements. A nondestructive full-field measurement technique is a valuable alternative to conventional methods. In this study, the digital image correlation (DIC) technique was adopted to investigate the bond behavior and buckling behavior of CFRP-steel composite members. The CFRP-to-steel bonded joint and the CFRPstrengthened square hollow section (SHS) steel column were tested to verify the suitability of the DIC technique. The stereo- DIC technique was utilized to measure continuous deformation. The bond-slip relationship of the CFRP-to-steel interface was derived using the DIC data. Additionally, a multi-camera DIC system consisting of four stereo-DIC subsystems was proposed and applied to the compressive test of CFRP-strengthened SHS steel column. The precise buckling location and CFRP delamination of the CFRP-strengthened SHS steel column were identified. The experimental results confirm that the stereo-DIC technique can provide effective measurements for investigating the behaviors of CFRP-steel composite members.

Precise rates in the law of the logarithm for the moment convergence of i.i.d. random variables

Tian-Xiao Pang,Ye Jiang,황교신,Zheng-Yan Lin 대한수학회 2008 대한수학회지 Vol.45 No.4

Let {X,Xn; n ≥ 1} be a sequence of i.i.d. random variables. Set Sn = X₁ + X₂ + ... + Xn, Mn =[수식] Then we obtain that for any -1 < b < 1/2, [수식] if and only if EX = 0 and EX² = σ² < ∞. Let {X,Xn; n ≥ 1} be a sequence of i.i.d. random variables. Set Sn = X₁ + X₂ + ... + Xn, Mn =[수식] Then we obtain that for any -1 < b < 1/2, [수식] if and only if EX = 0 and EX² = σ² < ∞.

Letters to the Editor : Successful Treatment of Hailey-Hailey Disease with Aminolevulinic Acid Photodynamic Therapy

( Xiao Xiao Yan ),( Hong Qing Tian ),( Chang Liang Wang ),( Bao Qi Yang ),( Wei Zhi Wu ),( Fu Ren Zhang ) 대한피부과학회 2015 Annals of Dermatology Vol.27 No.3

Multiple-motion mode switching robot platform

Xiao-Tian Sun,이수홍 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.12

Developing an intelligent robot platform that has multiple motion modes and can actively adjust the motion mode according to an operation situation is necessary in resolving the inability of single-mode robots to adapt completely to complex environments. In this study, we designed a robot that has multiple motion modes and can switch freely in these existing modes. The robot has the following modes:Four-legged walking, two-legged walking, pulse scrolling, and crawler movement. In the robot’s design, these modes are not just simple mechanisms involving superposition and motion switching. These modes involve a degree of freedom in reuse, thereby reducing the number of drives and obtaining a compact structure while achieving a coherent transition of each action mode. For higher load ratios, motion continuity are increased. The robot platform can balance itself during movement by adjusting its own mechanism or providing additional force and change its shape and posture over some obstacles by adjusting its own mechanism.

A self-normalized LIL for conditionally trimmed sums and conditionally censored sums

Tian-xiao Pang,Zheng-yan Lin 대한수학회 2006 대한수학회지 Vol.43 No.4

Let {X, X_n; nge 1} be a sequence of i.i.d. randomvariables which belong to the attraction of the normal law, andX_n^{(1)}, ldots, X_n^{(n)} be an arrangement of X_1, ldots,X_n in decreasing order of magnitude, i.e., |X_n^{(1)}|gecdots ge |X_n^{(n)}|. Suppose that {r_n} is a sequence ofconstants satisfying some mild conditions and d^{'}(t_{n_k}) isan appropriate truncation level, where n_k=[beta^k] and betais any constant larger than one. Then we show that theconditionally trimmed sums obeys the self-normalized law of theiterated logarithm (LIL). Moreover, the self-normalized LIL for

Patterns of Lymph Node Recurrence after Radical Surgery Impacting on Survival of Patients with pT1-3N0M0 Thoracic Esophageal Squamous Cell Carcinoma

Xiao-li Chen,,Tian-wu Chen,Zhi-jia Fang,Xiao-ming Zhang,Zhen-lin Li,Hang Li,Hong-jie Tang,Li Zhou,Dan Wang,Zishu Zhang 대한의학회 2014 Journal of Korean medical science Vol.29 No.2

The aim of this study was to investigate how patterns of lymph nodes recurrence after radical surgery impact on survival of patients with pT1-3N0M0 thoracic esophageal squamous cell carcinoma. One hundred eighty consecutive patients with thoracic esophageal squamous cell carcinoma underwent radical surgery, and the tumors were staged as pT1-3N0M0 by postoperative pathology. Lymph nodes recurrence was detected with computed tomography 3-120 months after the treatment. The patterns of lymph nodes recurrence including stations, fields and locations of recurrent lymph nodes, and impacts on patterns of survival were statistically analyzed. There was a decreasing trend of overall survival with increasing stations or fields of postoperative lymph nodes involved (all P<0.05). Univariate analysis showed that stations or fields of lymph nodes recurrence, and abdominal or cervical lymph nodes involved were prognostic factors for survival(all P<0.05). Cox analyses revealed that the field was an independent factor (P<0.05, odds ratio=2.73). Lymph nodes involved occurred predominantly in cervix and upper mediastinum (P<0.05). In conclusion, patterns of lymph node recurrence especially the fields of lymph nodes involved are significant prognostic factors for survival of patients with pT1-3N0M0 thoracic esophageal squamous cell carcinoma.

Expression patterns of five heat shock proteins in Sesamia inferens (Lepidoptera: Noctuidae) during heat stress

Xiao-Tian Tang,Meng Sun,Ming-Xing Lu,Yu-Zhou Du 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.18 No.3

Heat shock proteins (HSPs) play important roles in the adaptation of organisms to environmental changes. In this study, we explore the role of HSPs during heat stress in Sesamia inferens (Walker) (Lepidoptera: Noctuidae), an important pest of rice. In order to understand themechanistic basis of ecological adaptability and stress tolerance, we analyzed the expression profiles of genes encoding five S. inferens heat shock proteins (Sihsps) across temperature gradients by real-time quantitative PCR. Our results indicated that genes encoding ribosomal protein S13 (RPS13) and β-actin (ACTB) were the most stable reference genes under high temperature stress. The mRNA levels of Sihsp19.6, Sihsp20.6 and Sihsp83 were significantly upregulated by heat stress; however, the expression of Sihsp21.4 and Sihsc70 did not vary significantly. The massive increase in the expression of Sihsp19.6 and Sihsp20.6 by thermal stress suggests a critical role in preventing cellular damage to S. inferens. Moreover, the threshold temperatures (39 °C for Sihsp19.6, Sihsp20.6 and Sihsp83)may partly explain the more southern distribution of S. inferens. Our results also support the contention that the absence of introns may favor the expression of stress-responsive genes (e.g. Sihsp19.6, Sihsp20.6 and Sihsp83 in the present study).