Proceedings of the American Mathematical Society, 1999
Let p be a prime number and let GLn be the group of all invertible matrices over the prime field ... more Let p be a prime number and let GLn be the group of all invertible matrices over the prime field Fp. It is known that every irreducible GLnmodule can occur as a submodule of P , the polynomial algebra with n variables over Fp. Given an irreducible GLn-module ρ, the purpose of this paper is to find out the first value of the degree d of which ρ occurs as a submodule of P d , the subset of P consisting of homogeneous polynomials of degree d. This generalizes Schwartz-Tri's result to the case of any prime p.
In injection molding process, improving the part quality by reducing the warpage is an issue, esp... more In injection molding process, improving the part quality by reducing the warpage is an issue, especially with the thin-walled product. In this paper, the injection molding process was applied to a rectangular plate of 150 mm x 30 mm. The part thickness was varied from 1.0 mm to 2.5 mm. Three types of material as polypropylene (PP), acrylonitrin butadiene styrene (ABS), and polyvinyl chloride (PVC) were selected for observing the influence of volume shrinkage ratio on the warpage. Then, different weight ratios of CaCO 3 (10%, 20%, 30%, and 40%) additive were mixed with the PP material and then, the mixture was molded. The result shows that the volume shrinkage ratio of plastic material has a strong influence on the part warpage with the thickness of 1.0 mm, 1.5 mm, and 2.0 mm. However, with the thickness of 2.5 mm, the different warpage under three types of plastic is not strongly. With the CaCO 3 , the result shows that the more the CaCO 3 additive, the lesser is the part warped. However, with a thickness of 2.5 mm, the CaCO 3 has a negative influence on the warpage. In addition, this research was achieved by both simulation and experiment. The comparison shows that the simulation result and experiment result agree well.
This paper presents the test results of the WRF model error determination methods simulating the ... more This paper presents the test results of the WRF model error determination methods simulating the trajectory and intensity of storm Usagi in 2018. The study conducted three experiments: (1) The Combination of 11 options physical model, 21 composites, no increase in error correlation (MP); (2) Using a set of physical model, 21 composite components, multiplier growth factor l = 6.5 (MI); (3) Using a set of physical model, 21 compositions, no increase in error correlation (PF). Test results show that the multi-physics (MP) method has quite well simulated the intensity as well as the moving direction of the northern cold high pressure in the active Usagi storm area. As a result, The 2018 - Usagi 's trajectory and intensity is simulated in MP test better than in MI test and PF test. Specifically, at the 48-hour forecast term, the orbital prediction error of the MP test is below 350 km which is lower than the two tests (MI and PF), The orbital error in the MP test at the forecast term ...
Transactions of the American Mathematical Society, 2000
Let p be an odd prime number and let G be an extraspecial pgroup. The purpose of the paper is to ... more Let p be an odd prime number and let G be an extraspecial pgroup. The purpose of the paper is to show that G has no non-zero essential mod-p cohomology (and in fact that H * (G, Fp) is Cohen-Macaulay) if and only if |G| = 27 and exp(G) = 3.
Proceedings of the American Mathematical Society, 2003
We prove two theorems linking the cohomology of a prop group G with the conjugacy classes of its ... more We prove two theorems linking the cohomology of a prop group G with the conjugacy classes of its finite subgroups. The number of conjugacy classes of elementary abelian p-subgroups of G is finite if and only if the ring H * (G, Z/p) is finitely generated modulo nilpotent elements. If the ring H * (G, Z/p) is finitely generated, then the number of conjugacy classes of finite subgroups of G is finite. 1. Prop groups and elementary abelian prop subgroups Let G be a profinite group. Fix a fundamental system U of open neighborhoods
Science & Technology Development Journal - Science of The Earth & Environment, 2020
This paper presents some experimental results of the multi-physics ensemble Kalman filter method ... more This paper presents some experimental results of the multi-physics ensemble Kalman filter method which assimilating the satellite wind data in WRF model to simulate the track and intensity of the typhoon HaiYan (2013). The study conducted two experiments.: (1) Ensemble forecast with multi-physics ensemble Kalman filter assimilates the satellite wind data (CIMSS); (2) multi-physics Ensemble forecast (MPH). The results of atmospheric circulation analysis in the simulation started at 12 UTC (international time) until November 7, 2013, showing that the trend and intensity of the general circulation in the CIMSS test are similar to the real development. So the results of the storm trajectory forecast of CIMSS test at the 48-hour forecast limit onwards are better than the MPH test. Moreover, experimental results based on the results of the 6 simulations for simulation error, the track error in the CIMSS test decreased 14% and 14.3% respectively in the 48-hour forecast period and 72 hours ...
fault occurs at any part of the system, it will be detected and isolated while the remaining part... more fault occurs at any part of the system, it will be detected and isolated while the remaining parts of the vehicle continue to operate. Based on the physical structure of the vehicle, two separate but cooperative low-level controllers are built up to manage the front and rear sets of driving and steering systems. Each controller by itself can manipulate the vehicle, if the other is not working. When both controllers are working, they communicate with each other to cooperate in controlling the vehicle. The vehicle-following maneuver is supervised by the proposed controller which integrates all the fault diagnostic information from the vehicle to adjust its parameters and control commands. Simulation and experimental results show the efficiency of the fault-tolerant vehicle-following system. Before the end of the thesis, recommendations are given for future work on the vehiclefollowing control and fault tolerant control.
REV Journal on Electronics and Communications, 2017
In this paper, we design and implement a low profile frequency reconfigurable Planar Inverted-F A... more In this paper, we design and implement a low profile frequency reconfigurable Planar Inverted-F Antenna (PIFA) for WLAN, m-WiMAX and UMTS applications. Dierent from several conventional designs, the air layer in our antenna is removed, while the radiator patches and ground plane are printed on two sides of the same substrate. This makes the antenna structure thin and lightweight. The defected ground structure (DGS) and coplanar sorting-trips are also designed for adjusting lower operating frequencies without increasing the antenna’s size. Three PIN-diodes are used in appropriate positions for accurate switches between frequency bands. Moreover, the three radiator patches’ parameters are optimally selected on all configurations using Genetic Algorithm (GA). Simulation results show that depending on the ON/OFF states of the PIN-diodes, the antenna can operate in three applicable frequency bands, i.e., 2.1 GHz, 2.4 GHz, and 3.5 GHz with the corresponding peak gains of 0.48 dBi, 3.55 dB...
One new schiartane- type triterpene, heteroclitalactone N (1), and four known compounds (2–5), se... more One new schiartane- type triterpene, heteroclitalactone N (1), and four known compounds (2–5), seco-coccinic acid F, dihydroguaiaretic acid, schizanrin F, and kadsuralignan B were isolated from the stems of Kadsura heteroclita. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D-, 2D-NMR, and CD spectra as well as by comparing with the NMR data reported in the literature. The cytotoxic activities of all isolated compounds were evaluated on three human cancer cell lines. Compound 3 exhibited moderate to weak cytotoxic activities on three human cancer cell lines, OVCAR, HT-29, and A-549, with IC50 values ranging from 16.2 to 36.4 μM.
Trong những năm gần đây, ngay cang co nhiều kỹ thuật mới được ứng dụng trong cong nghệ phun ep nh... more Trong những năm gần đây, ngay cang co nhiều kỹ thuật mới được ứng dụng trong cong nghệ phun ep nhựa (Injection molding). Trong đo, phương phap giải nhiệt gian đoạn (Pulsed cooling) được ứng dụng nhằm nâng cao hiệu suất lam nguội trong qua trinh phun ep, cũng như rut ngắn thời gian gia cong sản phẩm. Tuy nhien, do hệ thống nay kha phức tạp, cũng như ảnh hưởng của qua trinh lam nguội đối với khuon va sản phẩm vẫn chưa được nghien cứu ro, vi vậy, điều chỉnh cac thong số của qua trinh giải nhiệt theo phương phap gian đoạn vẫn con la bai toan kho đối với người điều chỉnh may ep phun. Trong bai bao nay, thong qua phương phap mo phỏng, ảnh hưởng của cac thong số trong qua trinh lam nguội gian đoạn bao gồm: thời gian lam nguội, nhiệt độ lưu chất lam nguội, va nhiệt độ khuon sẽ được nghien cứu. Ngoai ra, bằng thực nghiệm, cac thong số tren sẽ được kiểm chứng với kết quả mo phỏng.
Proceedings of the American Mathematical Society, 1999
Let p be a prime number and let GLn be the group of all invertible matrices over the prime field ... more Let p be a prime number and let GLn be the group of all invertible matrices over the prime field Fp. It is known that every irreducible GLnmodule can occur as a submodule of P , the polynomial algebra with n variables over Fp. Given an irreducible GLn-module ρ, the purpose of this paper is to find out the first value of the degree d of which ρ occurs as a submodule of P d , the subset of P consisting of homogeneous polynomials of degree d. This generalizes Schwartz-Tri's result to the case of any prime p.
In injection molding process, improving the part quality by reducing the warpage is an issue, esp... more In injection molding process, improving the part quality by reducing the warpage is an issue, especially with the thin-walled product. In this paper, the injection molding process was applied to a rectangular plate of 150 mm x 30 mm. The part thickness was varied from 1.0 mm to 2.5 mm. Three types of material as polypropylene (PP), acrylonitrin butadiene styrene (ABS), and polyvinyl chloride (PVC) were selected for observing the influence of volume shrinkage ratio on the warpage. Then, different weight ratios of CaCO 3 (10%, 20%, 30%, and 40%) additive were mixed with the PP material and then, the mixture was molded. The result shows that the volume shrinkage ratio of plastic material has a strong influence on the part warpage with the thickness of 1.0 mm, 1.5 mm, and 2.0 mm. However, with the thickness of 2.5 mm, the different warpage under three types of plastic is not strongly. With the CaCO 3 , the result shows that the more the CaCO 3 additive, the lesser is the part warped. However, with a thickness of 2.5 mm, the CaCO 3 has a negative influence on the warpage. In addition, this research was achieved by both simulation and experiment. The comparison shows that the simulation result and experiment result agree well.
This paper presents the test results of the WRF model error determination methods simulating the ... more This paper presents the test results of the WRF model error determination methods simulating the trajectory and intensity of storm Usagi in 2018. The study conducted three experiments: (1) The Combination of 11 options physical model, 21 composites, no increase in error correlation (MP); (2) Using a set of physical model, 21 composite components, multiplier growth factor l = 6.5 (MI); (3) Using a set of physical model, 21 compositions, no increase in error correlation (PF). Test results show that the multi-physics (MP) method has quite well simulated the intensity as well as the moving direction of the northern cold high pressure in the active Usagi storm area. As a result, The 2018 - Usagi 's trajectory and intensity is simulated in MP test better than in MI test and PF test. Specifically, at the 48-hour forecast term, the orbital prediction error of the MP test is below 350 km which is lower than the two tests (MI and PF), The orbital error in the MP test at the forecast term ...
Transactions of the American Mathematical Society, 2000
Let p be an odd prime number and let G be an extraspecial pgroup. The purpose of the paper is to ... more Let p be an odd prime number and let G be an extraspecial pgroup. The purpose of the paper is to show that G has no non-zero essential mod-p cohomology (and in fact that H * (G, Fp) is Cohen-Macaulay) if and only if |G| = 27 and exp(G) = 3.
Proceedings of the American Mathematical Society, 2003
We prove two theorems linking the cohomology of a prop group G with the conjugacy classes of its ... more We prove two theorems linking the cohomology of a prop group G with the conjugacy classes of its finite subgroups. The number of conjugacy classes of elementary abelian p-subgroups of G is finite if and only if the ring H * (G, Z/p) is finitely generated modulo nilpotent elements. If the ring H * (G, Z/p) is finitely generated, then the number of conjugacy classes of finite subgroups of G is finite. 1. Prop groups and elementary abelian prop subgroups Let G be a profinite group. Fix a fundamental system U of open neighborhoods
Science & Technology Development Journal - Science of The Earth & Environment, 2020
This paper presents some experimental results of the multi-physics ensemble Kalman filter method ... more This paper presents some experimental results of the multi-physics ensemble Kalman filter method which assimilating the satellite wind data in WRF model to simulate the track and intensity of the typhoon HaiYan (2013). The study conducted two experiments.: (1) Ensemble forecast with multi-physics ensemble Kalman filter assimilates the satellite wind data (CIMSS); (2) multi-physics Ensemble forecast (MPH). The results of atmospheric circulation analysis in the simulation started at 12 UTC (international time) until November 7, 2013, showing that the trend and intensity of the general circulation in the CIMSS test are similar to the real development. So the results of the storm trajectory forecast of CIMSS test at the 48-hour forecast limit onwards are better than the MPH test. Moreover, experimental results based on the results of the 6 simulations for simulation error, the track error in the CIMSS test decreased 14% and 14.3% respectively in the 48-hour forecast period and 72 hours ...
fault occurs at any part of the system, it will be detected and isolated while the remaining part... more fault occurs at any part of the system, it will be detected and isolated while the remaining parts of the vehicle continue to operate. Based on the physical structure of the vehicle, two separate but cooperative low-level controllers are built up to manage the front and rear sets of driving and steering systems. Each controller by itself can manipulate the vehicle, if the other is not working. When both controllers are working, they communicate with each other to cooperate in controlling the vehicle. The vehicle-following maneuver is supervised by the proposed controller which integrates all the fault diagnostic information from the vehicle to adjust its parameters and control commands. Simulation and experimental results show the efficiency of the fault-tolerant vehicle-following system. Before the end of the thesis, recommendations are given for future work on the vehiclefollowing control and fault tolerant control.
REV Journal on Electronics and Communications, 2017
In this paper, we design and implement a low profile frequency reconfigurable Planar Inverted-F A... more In this paper, we design and implement a low profile frequency reconfigurable Planar Inverted-F Antenna (PIFA) for WLAN, m-WiMAX and UMTS applications. Dierent from several conventional designs, the air layer in our antenna is removed, while the radiator patches and ground plane are printed on two sides of the same substrate. This makes the antenna structure thin and lightweight. The defected ground structure (DGS) and coplanar sorting-trips are also designed for adjusting lower operating frequencies without increasing the antenna’s size. Three PIN-diodes are used in appropriate positions for accurate switches between frequency bands. Moreover, the three radiator patches’ parameters are optimally selected on all configurations using Genetic Algorithm (GA). Simulation results show that depending on the ON/OFF states of the PIN-diodes, the antenna can operate in three applicable frequency bands, i.e., 2.1 GHz, 2.4 GHz, and 3.5 GHz with the corresponding peak gains of 0.48 dBi, 3.55 dB...
One new schiartane- type triterpene, heteroclitalactone N (1), and four known compounds (2–5), se... more One new schiartane- type triterpene, heteroclitalactone N (1), and four known compounds (2–5), seco-coccinic acid F, dihydroguaiaretic acid, schizanrin F, and kadsuralignan B were isolated from the stems of Kadsura heteroclita. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D-, 2D-NMR, and CD spectra as well as by comparing with the NMR data reported in the literature. The cytotoxic activities of all isolated compounds were evaluated on three human cancer cell lines. Compound 3 exhibited moderate to weak cytotoxic activities on three human cancer cell lines, OVCAR, HT-29, and A-549, with IC50 values ranging from 16.2 to 36.4 μM.
Trong những năm gần đây, ngay cang co nhiều kỹ thuật mới được ứng dụng trong cong nghệ phun ep nh... more Trong những năm gần đây, ngay cang co nhiều kỹ thuật mới được ứng dụng trong cong nghệ phun ep nhựa (Injection molding). Trong đo, phương phap giải nhiệt gian đoạn (Pulsed cooling) được ứng dụng nhằm nâng cao hiệu suất lam nguội trong qua trinh phun ep, cũng như rut ngắn thời gian gia cong sản phẩm. Tuy nhien, do hệ thống nay kha phức tạp, cũng như ảnh hưởng của qua trinh lam nguội đối với khuon va sản phẩm vẫn chưa được nghien cứu ro, vi vậy, điều chỉnh cac thong số của qua trinh giải nhiệt theo phương phap gian đoạn vẫn con la bai toan kho đối với người điều chỉnh may ep phun. Trong bai bao nay, thong qua phương phap mo phỏng, ảnh hưởng của cac thong số trong qua trinh lam nguội gian đoạn bao gồm: thời gian lam nguội, nhiệt độ lưu chất lam nguội, va nhiệt độ khuon sẽ được nghien cứu. Ngoai ra, bằng thực nghiệm, cac thong số tren sẽ được kiểm chứng với kết quả mo phỏng.
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