The monocrystalline silicon is a promising material that could be used in solar cells that convert light into electricity. Although the cost of ordinary silicon (Si) solar cells has decreased significantly over the pa...The monocrystalline silicon is a promising material that could be used in solar cells that convert light into electricity. Although the cost of ordinary silicon (Si) solar cells has decreased significantly over the past two decades, the conversion efficiency of these cells has remained relatively high. While solar cells have a great potential as a device of renewable energy, the high cost they incur per Watt continues to be a significant barrier to their widespread implementation. As a consequence, it is vital to conduct research into alternate materials that may be used in the construction of solar cells. The heterojunction solar cell (HJSC), which is based on n-type zinc oxide (n-ZnO) and p-type silicon (p-Si), is one of the numerous alternatives of the typical Si single homojunction solar cell. There are many deficiencies that can be found in the published research on n-ZnO/p-Si heterojunction solar cell. Inconsistencies in the stated value of open circuit voltage (V<sub>oc</sub>) of the solar cell are one example of deficiency. The absence of a full theoretical study to evaluate the potential of the solar cell structure is another deficiency that can be found in these researches. A lower value of experimentally obtained V<sub>OC</sub> in comparison to the theoretical prediction based on the band-gap between n-ZnO and p-Si. There needs to be more consensus among scientists regarding the optimal conditions for the growth of zinc oxide. Many software’s are available for simulating and optimizing the solar cells based on these parameters. For this purpose, in this dissertation, I provide computational results relevant to n-ZnO/p-Si HJSC to overcome deficiencies that have been identified. While modeling and simulating the potential of the solar cell structure with AFORS-HET, it is essential to consider the constraints that exist in the real world. AFORS-HET was explicitly designed to mimic the multilayer solar cell arrangement. In AFORS-HET, we can add up to seven layers for solar cell layout. By using this software, we can figure out the open circuit voltage (V<sub>OC</sub>), the short circuit current (J<sub>SC</sub>), the quantum efficiency (QE, %), the heterojunction energy band structure, and the power conversion efficiency (PCE).展开更多
New strategies are needed to treat cancers that do not respond to chemotherapy or resist chemotherapy after responding initially. The objective of this study was to evaluate non-cytotoxic drugs against two of these ca...New strategies are needed to treat cancers that do not respond to chemotherapy or resist chemotherapy after responding initially. The objective of this study was to evaluate non-cytotoxic drugs against two of these cancers, melanoma and ovarian cancer. Imiquimod is an immune stimulant that induces apoptosis in cancer cells. Flexible-Heteroarotinoids (Flex-Hets) are small molecules that regulate growth, differentiation and apoptosis in cancer cells with reduced effects on normal cells. Both imiquimod and SHetA2 inhibited growth and induced apoptosis in the B16 melanoma cell line and cisplatin-sensitive A2780 and cisplatin-resistant OVCAR-3 ovarian cancer cell lines. The growth inhibition was additive in A2780 and B16, and synergistic in OVCAR-3. Both compounds inhibited endothelial tube branching in vitro and exerted an additive effect when combined. Various combinations of imiquimod and SHetA2 did not cause significant differences in the overall survival in the syngeneic B16 murine melanoma model. SHetA2 induced complete tumor regression and a melanoma-free natural life-span in two mice. These cures occurred in one of ten mice treated with oral SHetA2 and one of ten mice intratumorally-injected with SHetA2. Exploratory modeling of the distribution of survival times suggested that the two surviving mice represent rare events. Histologic evaluation of the tumors revealed that imiquimod induced necrosis, SHetA2 induced differentiated architecture and increased cytoplasm, both agents reduced mitotic indices and angiogenesis and neither agent counteracted the effects of the other. No overt toxicities were observed. In conclusion, imiquimod and SHetA2 exhibit complementary anti-cancer activity in vitro and SHetA2 has promise as a single agent.展开更多
采用限定变量的方法,运用AFORS-HET(Automat FOR Simulation of HETerostructures)软件计算模拟了不同厚度、掺杂浓度和禁带宽度的非晶硅薄膜背场以及不同厚度、禁带宽度的非晶硅本征层对a-Si(p)/c-Si(n)异质结太阳电池的影响。结果表明...采用限定变量的方法,运用AFORS-HET(Automat FOR Simulation of HETerostructures)软件计算模拟了不同厚度、掺杂浓度和禁带宽度的非晶硅薄膜背场以及不同厚度、禁带宽度的非晶硅本征层对a-Si(p)/c-Si(n)异质结太阳电池的影响。结果表明,在其它参数不变的情况下,增加较薄的背场和中间本征层,可以提高太阳电池的整体性能,其光电转换有很大程度提高,其最高转换效率可达20.75%;其中,中间本征层在厚度不超过20nm时,对电池的短路电流影响不大,而其它性能则相对下降;当非晶硅薄膜背场的掺杂浓度为1019cm-3以上,带隙为1.7eV,厚度为5nm时,电池性能最佳。展开更多
运用模拟软件AFORS-HET对TCO/a-Si∶H(n)/a-Si∶H(i)/c-Si(p)/Ag结构的异质结(HIT)太阳电池进行仿真,分析其光伏输出特性随发射层掺杂浓度、晶硅衬底掺杂浓度、透明导电氧化物薄膜(TCO)的选择以及TCO功函数的变化规律。结果显示,当发射...运用模拟软件AFORS-HET对TCO/a-Si∶H(n)/a-Si∶H(i)/c-Si(p)/Ag结构的异质结(HIT)太阳电池进行仿真,分析其光伏输出特性随发射层掺杂浓度、晶硅衬底掺杂浓度、透明导电氧化物薄膜(TCO)的选择以及TCO功函数的变化规律。结果显示,当发射层掺杂浓度大于1.0×1020cm^(-3),晶硅衬底掺杂浓度大于1.2×10^(16)cm^(-3),以ZnO为TCO层且Zn O的功函数低于4.4 e V时,电池的开路电压、短路电流密度、填充因子及电池转换效率达到最优值,光电转换效率最高达到19.18%。展开更多
Relatively little is known about the effects of estrogen on postischemic cerebral vasomotor dynamics after ischemic injury. Emerging hypotheses suggest that the timing after menopause at which hormone replacement is i...Relatively little is known about the effects of estrogen on postischemic cerebral vasomotor dynamics after ischemic injury. Emerging hypotheses suggest that the timing after menopause at which hormone replacement is initiated might be important and might modulate the potential benefits of estrogen on brain rescue once a cerebral ischemic event occurs. Therefore, we sought to determine if protracted hypoestrogenicity modifies estrogen’s protective effects on postischemic pial artery dilatory dysfunction and if the arachidonic acid metabolite 20-hydroxyeicosatetraeonic (20-HETE) contributes to the dysfunction. Pial artery dilation to acetylcholine was examined before and 1 hour after 15 minutes forebrain ischemia. The rat study groups included: sexually mature males (M), naive (N), OVX (OV), estrogen-treated OVX females (E1;estrogen started 1 week post ovariectomy) and delayed estrogen-treated (E10;started 10 weeks post ovariectomy) females. Postischemic responses were assessed before and after superfusion of the 20-HETE synthesis inhibitor N-hydroxy-N’-(4-butyl-2-methylphenyl)-formamidine (HET0016). Postischemic acetylcholine dilation was depressed in M, OV and E10 compared to N and E1 rats. Compared to E1, delayed estrogen replacement worsened acetylcholine-induced dilation. Postischemic microvascular estrogen receptor alpha (ERα) density was similar in the OV, E1 and E10 rats. Postischemic application of HET0016 failed to improve acetylcholine dilation. Continuous infusion of HET0016 during and after ischemia did not reverse postischemic pial vasodilatory dysfunction. Timing of estrogen replacement may be critical for vascular health after cerebral ischemic injury. Postischemic loss of acetylcholine reactivity does not appear to involve mechanisms related to 20-HETE synthesis or microvascular ERα expression.展开更多
Synchronous firing of neurons is thought to be important for information communication in neuronal networks. This paper investigates the complete and phase synchronization in a heterogeneous small-world chaotic Hindma...Synchronous firing of neurons is thought to be important for information communication in neuronal networks. This paper investigates the complete and phase synchronization in a heterogeneous small-world chaotic Hindmarsh Rose neuronal network. The effects of various network parameters on synchronization behaviour are discussed with some biological explanations. Complete synchronization of small-world neuronal networks is studied theoretically by the master stability function method. It is shown that the coupling strength necessary for complete or phase synchronization decreases with the neuron number, the node degree and the connection density are increased. The effect of heterogeneity of neuronal networks is also considered and it is found that the network heterogeneity has an adverse effect on synchrony.展开更多
文摘The monocrystalline silicon is a promising material that could be used in solar cells that convert light into electricity. Although the cost of ordinary silicon (Si) solar cells has decreased significantly over the past two decades, the conversion efficiency of these cells has remained relatively high. While solar cells have a great potential as a device of renewable energy, the high cost they incur per Watt continues to be a significant barrier to their widespread implementation. As a consequence, it is vital to conduct research into alternate materials that may be used in the construction of solar cells. The heterojunction solar cell (HJSC), which is based on n-type zinc oxide (n-ZnO) and p-type silicon (p-Si), is one of the numerous alternatives of the typical Si single homojunction solar cell. There are many deficiencies that can be found in the published research on n-ZnO/p-Si heterojunction solar cell. Inconsistencies in the stated value of open circuit voltage (V<sub>oc</sub>) of the solar cell are one example of deficiency. The absence of a full theoretical study to evaluate the potential of the solar cell structure is another deficiency that can be found in these researches. A lower value of experimentally obtained V<sub>OC</sub> in comparison to the theoretical prediction based on the band-gap between n-ZnO and p-Si. There needs to be more consensus among scientists regarding the optimal conditions for the growth of zinc oxide. Many software’s are available for simulating and optimizing the solar cells based on these parameters. For this purpose, in this dissertation, I provide computational results relevant to n-ZnO/p-Si HJSC to overcome deficiencies that have been identified. While modeling and simulating the potential of the solar cell structure with AFORS-HET, it is essential to consider the constraints that exist in the real world. AFORS-HET was explicitly designed to mimic the multilayer solar cell arrangement. In AFORS-HET, we can add up to seven layers for solar cell layout. By using this software, we can figure out the open circuit voltage (V<sub>OC</sub>), the short circuit current (J<sub>SC</sub>), the quantum efficiency (QE, %), the heterojunction energy band structure, and the power conversion efficiency (PCE).
文摘New strategies are needed to treat cancers that do not respond to chemotherapy or resist chemotherapy after responding initially. The objective of this study was to evaluate non-cytotoxic drugs against two of these cancers, melanoma and ovarian cancer. Imiquimod is an immune stimulant that induces apoptosis in cancer cells. Flexible-Heteroarotinoids (Flex-Hets) are small molecules that regulate growth, differentiation and apoptosis in cancer cells with reduced effects on normal cells. Both imiquimod and SHetA2 inhibited growth and induced apoptosis in the B16 melanoma cell line and cisplatin-sensitive A2780 and cisplatin-resistant OVCAR-3 ovarian cancer cell lines. The growth inhibition was additive in A2780 and B16, and synergistic in OVCAR-3. Both compounds inhibited endothelial tube branching in vitro and exerted an additive effect when combined. Various combinations of imiquimod and SHetA2 did not cause significant differences in the overall survival in the syngeneic B16 murine melanoma model. SHetA2 induced complete tumor regression and a melanoma-free natural life-span in two mice. These cures occurred in one of ten mice treated with oral SHetA2 and one of ten mice intratumorally-injected with SHetA2. Exploratory modeling of the distribution of survival times suggested that the two surviving mice represent rare events. Histologic evaluation of the tumors revealed that imiquimod induced necrosis, SHetA2 induced differentiated architecture and increased cytoplasm, both agents reduced mitotic indices and angiogenesis and neither agent counteracted the effects of the other. No overt toxicities were observed. In conclusion, imiquimod and SHetA2 exhibit complementary anti-cancer activity in vitro and SHetA2 has promise as a single agent.
文摘采用限定变量的方法,运用AFORS-HET(Automat FOR Simulation of HETerostructures)软件计算模拟了不同厚度、掺杂浓度和禁带宽度的非晶硅薄膜背场以及不同厚度、禁带宽度的非晶硅本征层对a-Si(p)/c-Si(n)异质结太阳电池的影响。结果表明,在其它参数不变的情况下,增加较薄的背场和中间本征层,可以提高太阳电池的整体性能,其光电转换有很大程度提高,其最高转换效率可达20.75%;其中,中间本征层在厚度不超过20nm时,对电池的短路电流影响不大,而其它性能则相对下降;当非晶硅薄膜背场的掺杂浓度为1019cm-3以上,带隙为1.7eV,厚度为5nm时,电池性能最佳。
文摘运用模拟软件AFORS-HET对TCO/a-Si∶H(n)/a-Si∶H(i)/c-Si(p)/Ag结构的异质结(HIT)太阳电池进行仿真,分析其光伏输出特性随发射层掺杂浓度、晶硅衬底掺杂浓度、透明导电氧化物薄膜(TCO)的选择以及TCO功函数的变化规律。结果显示,当发射层掺杂浓度大于1.0×1020cm^(-3),晶硅衬底掺杂浓度大于1.2×10^(16)cm^(-3),以ZnO为TCO层且Zn O的功函数低于4.4 e V时,电池的开路电压、短路电流密度、填充因子及电池转换效率达到最优值,光电转换效率最高达到19.18%。
文摘Relatively little is known about the effects of estrogen on postischemic cerebral vasomotor dynamics after ischemic injury. Emerging hypotheses suggest that the timing after menopause at which hormone replacement is initiated might be important and might modulate the potential benefits of estrogen on brain rescue once a cerebral ischemic event occurs. Therefore, we sought to determine if protracted hypoestrogenicity modifies estrogen’s protective effects on postischemic pial artery dilatory dysfunction and if the arachidonic acid metabolite 20-hydroxyeicosatetraeonic (20-HETE) contributes to the dysfunction. Pial artery dilation to acetylcholine was examined before and 1 hour after 15 minutes forebrain ischemia. The rat study groups included: sexually mature males (M), naive (N), OVX (OV), estrogen-treated OVX females (E1;estrogen started 1 week post ovariectomy) and delayed estrogen-treated (E10;started 10 weeks post ovariectomy) females. Postischemic responses were assessed before and after superfusion of the 20-HETE synthesis inhibitor N-hydroxy-N’-(4-butyl-2-methylphenyl)-formamidine (HET0016). Postischemic acetylcholine dilation was depressed in M, OV and E10 compared to N and E1 rats. Compared to E1, delayed estrogen replacement worsened acetylcholine-induced dilation. Postischemic microvascular estrogen receptor alpha (ERα) density was similar in the OV, E1 and E10 rats. Postischemic application of HET0016 failed to improve acetylcholine dilation. Continuous infusion of HET0016 during and after ischemia did not reverse postischemic pial vasodilatory dysfunction. Timing of estrogen replacement may be critical for vascular health after cerebral ischemic injury. Postischemic loss of acetylcholine reactivity does not appear to involve mechanisms related to 20-HETE synthesis or microvascular ERα expression.
基金supported by the National Natural Science Foundation of China (Grant No 10872014)
文摘Synchronous firing of neurons is thought to be important for information communication in neuronal networks. This paper investigates the complete and phase synchronization in a heterogeneous small-world chaotic Hindmarsh Rose neuronal network. The effects of various network parameters on synchronization behaviour are discussed with some biological explanations. Complete synchronization of small-world neuronal networks is studied theoretically by the master stability function method. It is shown that the coupling strength necessary for complete or phase synchronization decreases with the neuron number, the node degree and the connection density are increased. The effect of heterogeneity of neuronal networks is also considered and it is found that the network heterogeneity has an adverse effect on synchrony.
