An Evolutionary History of the Production Function

Xin, Yu,Han, Sung-Soo 명지대학교 북한연구소 2004 북한연구 Vol.7 No.-

My goal in this paper is to apply the evolutionary idea to study the history of the production function and argue that the economic theories about the production function have been developing gradually. There is a clear track along which the production function evolves from its most primitive prototype to its fancy mathematical form today in the more than 200 years history of the economic thoughts. Specifically, I focus my discussion on the origin and development of the Cobb-Douglas production function, which is the most ubiquitous function since its "birth" in 1928. The history of Cobb-Douglas production function is a history of the development of the related economic theories. It is necessary to put it in the historical background in order to avoid entangling oneself with piles of data without thinking about the theory for the measurement.

Molecular evolutionary analysis reveals Arctic-like rabies viruses evolved and dispersed independently in North and South Asia

Xin Yu,Hongwei Zhu,Yongheng Bo,Youzhi Li,Jianlong Zhang,Linlin Jiang,Guozhong Chen,Xingxiao Zhang,Yongjun Wen 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.1

Background: Arctic-like (AL) lineages of rabies viruses (RABVs) remains endemic in some Arctic and Asia countries. However, their evolutionary dynamics are largely unappreciated. Objectives: We attempted to estimate the evolutionary history, geographic origin and spread of the Arctic-related RABVs. Methods: Full length or partial sequences of the N and G genes were used to infer the evolutionary aspects of AL RABVs by Bayesian evolutionary analysis. Results: The most recent common ancestor (tMRCA) of the current Arctic and AL RABVs emerged in the 1830s and evolved independently after diversification. Population demographic analysis indicated that the viruses experienced gradual growth followed by a sudden decrease in its population size from the mid-1980s to approximately 2000. Genetic flow patterns among the regions reveal a high geographic correlation in AL RABVs transmission. Discrete phylogeography suggests that the geographic origin of the AL RABVs was in east Russia in approximately the 1830s. The ancestral AL RABV then diversified and immigrated to the countries in Northeast Asia, while the viruses in South Asia were dispersed to the neighboring regions from India. The N and G genes of RABVs in both clades sustained high levels of purifying selection, and the positive selection sites were mainly found on the C-terminus of the G gene. Conclusions: The current AL RABVs circulating in South and North Asia evolved and dispersed independently.

Effect of kaolin pretreatment on the structure and properties of metakaolin phosphate-based geopolymers

Xin Yu,Chengxin Ren,Wenlong Xu,Lina Xu,Qingbo Tian 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.1

This study focused on the preparation of metakaolin-based phosphate-activated geopolymers (MKPGs) using kaolin pretreatedat 950 °C for varying times as a precursor. It was found that kaolinite quickly transformed into amorphous metakaolin (MK)and then transitioned from a disordered phase to an ordered phase, resulting in precipitation of kyanite and mullite withincreasing calcination time. The formation of the kyanite phase had an adverse effect on geopolymerization, which causeda decrease in the strength of the MKPGs. The precipitation of the mullite phase hindered the geopolymerization reactionbetween phosphoric acid and MK, and the geopolymer failed to solidify. As the calcination time increased from 10 min to 60min, the compressive strength of the geopolymers increased and then decreased. The maximum strength of the geopolymerscreated from MK calcined for 30 min was 132.1 MPa.

The Spillover Effects of Privatization on Efficiency and Income Inequality in China

Xinyu Li(Xinyu Li),Sunghwan Kim(Sunghwan Kim),Yongshang Liu(Yongshang Liu) The International Academy of Global Business and T 2023 The International Academy of Global Business and T Vol.19 No.1

Purpose - This study examines the spatial and inter-temporal spillover effects of privatization on the corporate efficiency and regional income inequality of Chinese state-owned enterprises (SOEs). Design/Methodology/Approach - The spatial Durbin model (SDM) is used in regressions to examine the spatial and inter-temporal spillover effects of the privatization of SOEs on improving the efficiency and income inequality of Chinese firms across regions. A panel dataset of Chinese-listed firms from 2008 to 2018 is used. The stochastic frontier analysis method is applied in estimating corporate efficiency. Findings - First, the privatization of Chinese SOEs increased their efficiency, but exacerbated their income inequality. Second, the globalization activities after the privatization of Chinese SOEs increased their efficiency, but exacerbated their income inequality. Specifically, exports decrease income inequality, while outward foreign direct investment or OFDI has an inverse U-shaped effect on income inequality. Third, the privatization improved overall corporate efficiency within the province and that of neighboring provinces. Fourth, the Chinese SOE firms after privatization aggravated income equality within the province and that of neighboring provinces. Research Implications - In general, the results of this study indicate that the privatization of SOEs and the globalization activities after the privatization have improved the efficiency of Chinese firms, but worsened income equality within the province and that of neighboring provinces. Therefore, there is a strong need for governmental policies to cure income equality in provinces around the location of privarized firms.

Xylazole inhibits NO-cGMP pathway in fetal rat nerve cells

Xinyu Wang,Yue Wu,Lin Liu,Hui Bai,Zhiheng Zhang,Mingchao Zhao,Tianwen Ma,Xiaopeng Song,Lina Jia,Liangyu Lv,Yue Yu,Xinyu Xu,Hong Chen,Li Gao 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.1

Background: Xylazole (Xyl) is a veterinary anesthetic that is structurally and functionally similar to xylazine. However, the effects of Xyl in vitro remain unknown. Objectives: This study aimed to investigate the anesthetic mechanism of Xyl using fetal rat nerve cells treated with Xyl. Methods: Fetal rat nerve cells cultured for seven days were treated with 10, 20, 30, and 40 μg/ mL Xyl for 0, 5, 10, 15, 20, 25, 30, 45, 60, 90, and 120 min. Variations of amino acid neurotransmitters (AANTs), Nitric oxide-Cyclic GMP (NO-cGMP) signaling pathway, and ATPase were evaluated. Results: Xyl decreased the levels of cGMP and NO in nerve cells. Furthermore, Xyl affected the AANT content and Na+-K+-ATPase and Ca2+-Mg2+-ATPase activity in nerve cells. These findings suggested that Xyl inhibited the NO-cGMP signaling pathway in nerve cells in vitro. Conclusions: This study provided new evidence that the anesthetic and analgesic effects of Xyl are related to the inhibition of the NO-cGMP signaling pathway.

Comparison of Clinical and Radiographic Outcomes Between Transforaminal Endoscopic Lumbar Discectomy and Microdiscectomy: A Follow-up Exceeding 5 Years

Xinyu Yang,Shijun Zhang,Junxiao Su,Sai Guo,Yakubu Ibrahim,Kai Zhang,Yonghao Tian,Lianlei Wang,Suomao Yuan,Xinyu Liu 대한척추신경외과학회 2024 Neurospine Vol.21 No.1

Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio. Conclusion: Both TELD and MD provide generally satisfactory long-term clinical outcomes for patients with LDH. TELD can be used as a reliable alternative to MD with less surgical trauma. Modic type II changes, decreased preoperative intervertebral height, and a high body mass index are predictors of a poor prognosis. Objective: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). Methods: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients’ clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. Results: During a mean follow-up of 5.5 years (range, 5–7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio.

First principles study of monolayer Sb2S2Te and a mathematical model of a thin-film thermoelectric generator with maximum power point tracing

Liu Xinyu,Yuan Shaoheng,Gu Bo,Chen Qiongxuan,Pu Xinyu,Zhang Jiangtao 한국물리학회 2022 Current Applied Physics Vol.36 No.-

The result of the structural, electronic and thermoelectric performance of monolayer Sb2S2Te, which is a brannew material, is calculated by using the method of full-potential linearized augmented plane-wave (FP-LAPW), and the exchange-correlation potential selected in this paper is generalized gradient approximation (GGA) scheme. There are no negative frequencies in the calculated phonon spectra, which demonstrates that dynamics of monolayer Sb2S2Te is stable in theory. The average value of lattice thermal conductivity (κl) is smaller than that of other thermoelectric (TE) materials, and monolayer Sb2S2Te has larger figure of merit (ZT) comparing with other well-known materials. According to the TE parameters (Seebeck coefficient S, electrical conductivity σ, electronic thermal conductivity κe and lattice thermal conductivity κl) of monolayer Sb2S2Te, an idealized model of thermoelectric generator (TEG) and a realistic model of maximum power point tracking (MPPT) are built. In addition, this paper studies the influence of different temperature zones, different temperature differences, cross sectional area, height and the number of P–N junction on output power and conversion efficiency of TEG. The results of physical calculation and simulation models show that the conversion efficiency of TEG of monolayer Sb2S2Te is larger than or close to that of other well-known materials, and the tracking accuracy of MPPT proposed in this paper is higher than or close to that of other researches.

Backstepping Synchronous Control of Simplified Supersonic Missile

Xinyu Wang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.12

A new kind of novel control method which is named backstepping synchronous control is firstly proposed in this paper. It is a kind of method that can applied in any general system as widely as PID control, variable structure control and any other control method. Synchronization was most frequently used in secure communication and else in the past, but here its concept was successfully used to construct a new control method. It is similar to model referenced adaptive control but it is still different from that. An auxiliary system with several virtual synchronous inputs and a real input is constructed to cope the uncertainties of original system. The synchronous inputs are designed to realize the synchronization between auxiliary system and original system. Since the real input is designed according to the auxiliary system without uncertainty by using backstepping method, so it is easy to design. Because the synchronous input is decoupling so it is easy to cope with uncertainties. In this paper, simplified supersonic missile system was taken as an example to show the design process and stability analysis of the new method. Also, it was compared with traditional PID control and backstepping control method. At last, detailed numerical simulations were done to testify the effectiveness of the proposed method.

Determination of Incident Angle and Position of Optimal Mode Ultrasonic Beam for Flaw Detection in Anisotropic and Imhomogeneous Weldments by Ray Tracing

Xinyu Zhao,Sung-Jin Song,Hak-Joon Kim,Tie Gang,Suk-Chull Kang,Yong Hwan Choi,Kyungcho Kim,Sung-Sik Kang 한국비파괴검사학회 2007 한국비파괴검사학회지 Vol.27 No.3

Determination of Incident Angle and Position of Optimal Mode Ultrasonic Beam for Flaw Detection in Anisotropic and Inhomogeneous Weldments by Ray Tracing

Xinyu Zhao,송성진,김학준,Tie Gang,Suk-Chull Kang,Yong Hwan Choi,Kyungcho Kim,Sung-Sik Kang 한국비파괴검사학회 2007 한국비파괴검사학회지 Vol.27 No.3

Ultrasonic inspection of austenitic steel weldments is a truly difficult task due to complicated wave propagation phenomena such as beam skewing, splitting and distortion. In order to understand these phenomena and design proper inspection procedures, simulation is increasingly paid more attention to. This article addresses a ray tracing based approach to determine incident angle and position of optimal wave mode ultrasonic beam for flaw detection in anisotropic and inhomogeneous austenitic steel weldments. Specially, the optimal mode of ultrasonic wave wave is selected by ray tracing simulation, and an optimization approach based on ray tracing and bi-section search is proposed in order to find the ray path connecting two given points in weldments. With help of this approach, the optimal incident angle and position of ultrasonic beam can be determined for a given flaw position.