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Obesity is a metabolic disease and its relation with male subfertility has aroused a growing concern. However, it is unclear whether gene expression and post-translational modifications (PTMs), two vital molecular mechanisms regulating cellular functions, are associated with obesity-induced male reproductive dysfunction. In this study, male obesity with compromised sperm motility was induced by a high-fat diet (HFD) using a mouse model. The expression of motility related-genes, the level of histone modifications, and the global profiles of post-translational modifications (PTMs), were examined in testes of HFD and control mice by quantitative real-time PCR and western blot, respectively. Outer dense fiber protein 2, a major component of outer dense fibers in the sperm tail, is the most obviously down-regulated gene out of 11 evaluated genes, showing a reduction of about 50% RNA level in testes of obese male mice compared with that in control mice. Semi-quantitative analysis of the western blot demonstrated that ∼56% enrichment of di-methylated histone (H)3 lysine (K)36, ∼59% enrichment of 2-hydroxyisobutyrylated H4K8, ∼32% decrease of propionylated H3K23, ∼33% decrease of crotonylated H4K8, and ∼45% decrease of acetylated H3K122 and H4K8 were detected in testes of male HFD mice compared with that in control mice. In addition, male obesity up-regulated the testicular levels of ubiquitination by ∼18%, tyrosine nitration by ∼20%, lysine succinylation by ∼25%, lysine benzoylation by ∼28%, lysine malonylation by ∼32%, lysine glutarylation by ∼36%, lysine propionylation by ∼42%, lysine 2-hydroxyisobutyrylation by ∼45%, and SUMO1 modification by ∼59%, and down-regulated the testicular levels of O-GlcNAcylation by ∼12%, lysine crotonylation by ∼22%, and lysine acetylation by 35%. These findings indicate that altered gene expression and PTMs are associated with the obesity-induced male reproductive dysfunction.

As a plasticizer widely used in society, tri-ortho-cresyl phosphate (TOCP) is reported to inhibit spermatogenesis and growth of spermatogonial stem cells. However, its effects on female reproductive system are virtually unknown. The present study investigated the effects of TOCP on ovarian follicle development by using mouse model of chronic TOCP exposure, and examined the expression of the core components of the Hippo pathway, which had been proven to be crucial for ovarian follicle development. Furthermore, through up-regulation of Hippo-yes-associated protein 1 (Yap1) in ovaries, the potential protective effects of Yap1 over-expression on TOCP-induced ovarian dysfunction were observed. The results showed that TOCP impaired ovarian function in a dose-dependent manner, and the expression of the Hippo pathway changed significantly in TOCP-exposed ovaries. Further, YAP1 over-expression partially reversed the TOCP-induced ovarian impairment. Collectively, these data indicate that the Hippo pathway is involved in the mechanism by which TOCP elicits ovarian function impairment.

Progestin and adipoQ receptor 7 (PAQR7) as an indispensable member of membrane progestin receptors in the Progestin and adipoQ receptor (PAQR) family that mediates nongenomic progesterone actions, initiated rapidly at the cell surface. Previous research demonstrated the distribution of PAQR7, which was mainly expressed in reproductive tissues, including ovary and testis. In the male reproductive system, PAQR7 is involved in progestin-induced sperm hypermotility. However, reports studying PAQR7 in female reproductive tissue mainly concentrate on oocyte maturation in fish, its expression in the ovary and gestational tissue, and regulation of uterine functions in mammals. Despite recent advances, many aspects of progestin signaling through PAQR7 are still unclear, especially in female reproductive tissue. Therefore, we reveal the structure and characteristics of PAQR7 and conclude the putative progestin-induced action mediated by PAQR7 in female reproductive tissue, such as the development of ovarian follicles, apoptosis of granulosa cells, oocyte maturation, and development of certain diseases, among others, to review the function of PAQR7 in the female reproductive system in detail.

Tanshinones are major bioactive diterpenoids of Salvia miltiorrhiza roots used for the treatment of cardiocerebral diseases. To develop effective elicitation and bioprocess strategies for the enhanced production of tanshinones, ultraviolet-B (UV-B) irradiation and methyl jasmonate (MeJA) elicitation were applied alone or in combination respectively in S. miltiorrhiza hairy root cultures. Our results showed 40-min UV-B irradiation at 40μW/cm(2) stimulated tanshinone production without any suppression of root growth, suggesting a new effective elicitor to S. miltiorrhiza hairy root cultures for tanshinone production. Moreover, the combined treatment of UV-B irradiation and MeJA exhibited synergistic effects on the expression levels of 3-hydroxy-3-methylglutaryl-CoA reductase (SmHMGR) and geranylgeranyl diphosphate synthase (SmGGPPS) genes in the tanshinone biosynthetic pathway. When hairy roots of 18-day-old cultures were exposed to the combined elicitation for 9days, the maximum production of tanshinone reached to 28.21mg/L, a 4.9-fold increase over the control. The combined elicitation of UV-B and MeJA was firstly used to stimulate the production of biologically important secondary metabolites in hairy root cultures.

One new Zn(Ⅱ) metal–organic framework, [Zn3(tib)2(BPT)2]·7H2O (ZZIT-1) [ZZIT-1 = Zhengzhou Institute of technology, tib = 1,3,5-tris(1-imidazolyl)benzene, H3BPT = biphenyl-3,4′,5-tricarboxylic acid], has been synthesized and characterized. ZZIT-1 is a two-fold interpenetrating 3D framework structure. The gas/vapor adsorption behavior and luminescence of the complex have been studied. Notably, ZZIT-1 can selectively adsorb CO2 over N2, and MeOH over EtOH, and these adsorption results have been corroborated by theoretical calculations. Most interestingly, ZZIT-1 shows unique selectivity for the detection of acetone through a fluorescence quenching mechanism in the solid state at room temperature.

Cyanotis arachnoidea contains a rich source of bioactive phytoecdysteroids (i.e. analogues of insect steroid hormones). 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) supplies mevalonate for the synthesis of many secondary metabolites including 20-hydroxyecdysone (20E), one of metabolism-enhancing phytoecdysteroids. In this study, in order to develop a sustainable source of 20E, cell suspension cultures were established from shoot cultures of C . arachnoidea , and a full length cDNA encoding HMGR (designated as CaHMGR ) was cloned and characterized. The cDNA contained 2037 nucleotides with a complete open reading frame (ORF) of 1800 nucleotides, which was predicted to encode a peptide of 599 amino acids. Expression analysis by real-time PCR revealed that CaHMGR mRNA was abundant in C . arachnoidea stems, roots and leaves. When cultivated in Murashige & Skoog medium supplemented with 0.2 mg L −1 1-naphthlcetic acid (NAA) and 3.0 mg L −1 6-benzyladenine (6-BA), C . arachnoidea cells in suspension culture grew rapidly, yielding 20E (124.14 μg L −1 ) after 12 days. The content of 20E in cell cultures elicited by 0.2 mM methyl jasmonate (MeJA), 100 mg L −1 yeast elicitor (YE) or 25 μM AgNO 3 was increased 8-, 2-, and 6-fold over the control, respectively. Quantitative real-time PCR analysis showed that CaHMGR was expressed at a higher level under the treatment of MeJA or Ag + elicitor. Our results suggested that 20E accumulation may be the result of the expression up-regulation of CaHMGR involved in the biosynthesis under the treatment of various elicitors.

Artemisinin, an endoperoxide sesquiterpene lactone, is an effective antimalarial drug isolated from Artemisia annua L. In this study, a low dose (1.44 kJm(-2)d(-1)) of UV-B radiation (280-320 nm) for short-term (1h per day for 10 days) was applied to A. annua seedlings to stimulate artemisinin production. UV-B treatment not only induced the generation of reactive oxygen species (ROS), enhanced peroxidase activity and endogenous content of abscisic acid (ABA), but stimulated the biosynthesis of artemisinin in the seedlings. Here, transcriptomic changes during UV-B radiation in A. annua were detected using an Agilent GeneChip with 43,692 probe sets. In total, 358 transcripts were identified as differentially expressed under UV-B stress, of which 172 transcripts increased and 186 transcripts decreased in abundance. In terms of biological processes, gene ontology (GO) terms including primary carbohydrate and nitrogen compound metabolic processes were enriched in UV-B-repressed genes. The up-regulated genes were enriched in response to stress, ROS generation, hormone (ethylene, ABA) stimulus and cell cycle control. The expression of key enzymes such as amorpha-4,11-diene synthase (ADS) and cytochrome P450 dependent monooxygenase/hydroxylase (CYP71AV1), and related WRKY transcription factors was up-regulated significantly for artemisinin biosynthesis. This profile of global gene expression patterns during UV-B stress will be valuable for further identification of the enzymes involved in artemisinin biosynthesis.

There is a global need for an ideal method of male contraception. However, the development of male contraceptives has not been well successful. Research on sperm-specific ion channels, especially the recent advance obtained from electrophysiological studies, has emphasized the conception that those channels are targets with the most potential to develop non-hormonal male contraceptives. While summarizing the general options for male contraception, this review focuses on the properties and functions of sperm ion channels together with the attempts of utilizing these channels to develop male contraceptives. We believe that a deeper insight into the signaling and molecular mechanisms by which ion channels regulate sperm functions will pave the way for developing novel male-based contraceptives.

An effective protocol for plant regeneration from hairy root (HR) via indirect somatic embryogenesis was established in medicinal plant Salvia miltiorrhiza. On the MS medium with 1.0 mg l−1 2, 4-dichlorophenoxyacetic (2,4-D) and 0.5 mg l−1 6-benzylaminopurine (6-BA), the hairy root explants produced embryogenic callus. After transferred to the MS medium with 0.05 mg l−1 α-naphthylacetic acid (NAA) and 0.5 mg l−1 6-BA, the embryogenic callus produced cotyledonary somatic embryo and developed into plantlets. PCR analyses revealed plants regenerated from HRs (HR-plants) retained rolA, B, C and D genes. Morphologically, HR-plants displayed wrinkled leaves, longer and thickened taproots. The biomass of roots and shoots of HR-plants increased by 2.7- and 1.5-fold, respectively, and the total content of tanshinones in their roots raised by 79.5%, in comparison with wild type (WT)-plants. The gene expression of 3-hydroxy-3-methylglutaryl CoA redutase (HMGR) and 1-deoxy- d -xylulose 5-phosphate reductoisomerase (DXR), the first two key enzymes in the pathway of tanshinone synthesis, was up-regulated in roots of HR-plants. This study offers an effective breeding method and material for producing tanshinones.

The performance evaluation of Virtual Research Center (VRC) is an intrinsically complex multi-dimensional process and it should be evaluated and compared in a multi-criteria analysis method. To solve the problems caused by the fuzzy decision making, quantifying the qualitative indexes and dealing with the interdependence and interaction of some indexes during the process of VRC performance evaluation, a comprehensive performance evaluation method based on triangular fuzzy number and analytic network process (TFN-ANP) is proposed. In the method, an index evaluation system is first established and the interactive relationships of the evaluation indexes are analyzed. Secondly, the index evaluation decision-making matrix is constructed and the indexes attribute values are fuzzed with triangular fuzzy numbers. Thirdly, the evaluative indexes weights are determined by analytic network process. Then the concrete solving process is derived and the fuzzy utility value weights are ranked by the priority method with decision maker risk preference. In the end, the four project teams of Yalong River VRC are taken as examples, then their comprehensive performances are evaluated by TFN-ANP model and the utility value priorities are ranked, which could provide decision supports for VRC to optimize operational performance. In addition, a comparison with the previous method is performed, and experimental results are encouraging, which fully demonstrates the effectiveness and superiority of the proposed approach.

An Monte Carlo (MC) simulation program has been used to study ion mass dependence for the low energy channeling of natural- and pseudo-Ar ions in single-wall nanotubes. The MC simulations show that the channeling critical angle Psi(C) obeys the (E) (- 1/2) and the (M-1) (- 1/2) rules, where E is the incident energy and M-1 is the ion mass. The reason for this may be that the motion of the channeled (or de-channeled) ions should be correlated with both the incident energy E and the incident momentum (2M(1)E)(1/2), in order to obey the conservation of energy and momentum. (c) 2008 Elsevier B.V. All rights reserved.

Based on the Monte Carlo simulation conjoined with the embedded atom method (EAM) potentials, the double species model is established to study relaxation of impure Ni3Al grain boundaries. The present double species model suggests that the impure atoms are not only segregating species but also inducing species. The present model also suggests that study of combination of the positive (the impure atoms induce Ni atoms to substitute into Al sites) and the negative (the impure atoms substitute into Ni sites) bulk effects of impure atoms is available, in order to understand dependence of the cohesion of the impure Ni3Al grain boundary (or the Ni enrichment at the impure Ni3Al grain boundary) on the bulk concentration of impure atoms. The double species model is clarified in comparison between the Ni3Al-B and the Ni3Al-Mg systems. (C) 2004 Elsevier B.V. All rights reserved.

Monte Carlo simulation with the energetics described by the embedded atom method (EAM) has been employed to calculate not only grain boundary concentration profiles of Ni, Mg and Al, but also dependence of the grain boundary cohesion on the Mg bulk concentration, for the Ni3Al-x at.% Mg (100%Ni\100%Ni)[001]/Sigma5(210)/36.87degrees grain boundary, at equilibrium. We suggest that the bulk effects of Mg on the grain boundary include the primarily positive effect on the Ni enrichment at the grain boundary, i.e. the Mg atoms induce Ni atoms to substitute into Al sites, the secondarily positive effect on it, i.e. the Mg atoms substitute into Al sites, and the negative effect on it, i.e. the Mg atoms substitute into Ni sites. For the Ni3Al-x at.% Mg grain boundary, at the equilibrium, the calculations show that when x (the Mg bulk concentration) increases from 0.1 to 0.5, the Mg enrichment increases, both the Ni enrichment and the Al depletion maximizes at x = 0.2. The calculations also show the best cohesion of the grain boundary at x = 0.2. (C) 2003 Elsevier B.V. All rights reserved.

The embedded atom method (EAM) has been used to calculate boundary concentration distributions of Ni, Al, and B, and B probabilities in the "interstitial" and the "substitutional" sites, at the Ni3Al-x at.% B (100% Ni/100% Ni) [001]/Sigma5(210)/36.87degrees grain boundary at the equilibrium. It has been proposed by us that the bulk effects of B on the grain boundary include the main effect, that is, the B atoms induce Ni atoms to substitute into Al sites, and the sub-effect, that is, the B atoms substitute into Ni sites. In this work, it is found that at as x increases from 0.1 to 1.0, the B probability in the "interstitial" sites decreases from 97.3% to 38.8%, while that in the "substitutional" sites increases from 2.7% to 61.2%. It is also found that owing to combination of the main effect and the sub-effect, corresponding to B enrichment increasing, the Ni enrichment and the Al depletion become more and more obvious when x increases from 0.1 to 0.5. Then, corresponding to B enrichment decreasing, the Ni enrichment and the Al depletion also become more and more obvious when x decreases from 0.9 to 0.5. Thus, between low (x = 0.1) and high (x = 0.9) B bulk concentrations, there is a B bulk concentration (x = 0.5), at which the Ni enrichment and the Al depletion become the most obvious, and Ni is approximately saturated. (C) 2002 Elsevier Science B.V All rights reserved.

We have applied the embedded atom method (EAM). to calculate boundary concentration distributions of Ni, Al and B, and B probabilities in the "interstitial" and, the "substitutional" sites, at the Ni3Al-x at.% B (100% Ni\100% Ni) [001]/Sigma5(210)/36.87 degrees. grain boundary at the equilibrium. We propose that the bulk effects of B on the grain boundary include the positive effect on the Ni enrichment at the grain boundary, i.e. the B atoms induce Ni atoms to substitute into Al sites, the negative effect on it, i.e. the B atoms substitute into Ni sites, and the neutral effect on it, i.e. the B atoms insert into interstices in the grain boundary. Our calculations show that owing to combination of the positive effect and the negative effect, corresponding to B-enrichment increasing, the Ni-enrichment and the Al-depletion become more and more obvious, when x increases from 0.1 to 0.5. Then, corresponding to B-enrichment decreasing, the Ni-enrichment and the Al-depletion also become more and more obvious, when x decreases from 0.9 to 0.5. Thus, between low (x = 0.1) and high (x = 0.9) B bulk concentrations, there is a B bulk concentration (x = 0.5), at which the Ni-enrichment and the Al-depletion become the most obvious, even if Ni is approximately saturated. (C) 2001 Elsevier Science B.V. All rights reserved.

This work has applied the embedded atom method (EAM) to calculate concentration distribution of Mg. Ni and Al at a Ni3Al-5 at.% Mg grain boundary. and the Mg-induced distortion energies at the grain boundary, the bulk and the free surface. The calculated concentration distributions show that Mg segregation is present with Al-depletion and Ni-enrichment at the grain boundary. The cause might be not only that at the same zone, the Mg-induced distortion energy in the site of Al is always negative and lower than that of Ni. but also that the Mg-induced distortion energy in the Al site at the grain boundary is the lowest among those at all zones. (C) 2001 Elsevier Science B.V. All rights reserved.

sWe have developed a mass- and charge-dependent equation to predict theoretical critical angles for ion channeling in carbon nanotubes We focus M (ion mass) effects how to reduce Ze (ion nucleus charge) effects on Psi(c) (critical angles). As an instance, we give theoretical critical angels of He, Ne, Ar, Kr, Xe and Rn ion channeling in carbon nanotubes We find that for (10, 10) single-wall carbon nanotubes, Psi(c)(He)approximate to:. Psi(c)(Ne) Psi(c)(Ar) Psi(c)(Xe)approximate to Psi(c)(Rn)approximate to 23 3 (keV/E)(1/2) deg This is because (Z/M)(1/2).--L- 066 lamur112 (C) 2010 Elsevier B V All rights reserved.

Lindhard proposed his classical equation for the critical channeling angle from consideration of conservation of transverse energy. We generalize those ideas via consideration of conservation of transverse momentum, and propose an improved equation. A dimensional analysis of the problem is also presented, and that analysis puts our arguments and results on a firm footing.

Influence of cascade atoms on the preferential emission of isotopes during sputtering has been studied by a static Monte Carlo simulation program, for Zero-fluence and low-energy (below 1 keV) Xe ion bombardment of a Cu-63(0.5) Cu-65(0.5) target. Calculations show that the probabilities of the sputtered cascade atoms of Cu-63 and Cu-65 are over 80%. The calculations also show that towards the surface, the momentum flux of the cascade atoms of Cu-65 is much more than that of Cu-65. The momentum asymmetry in the collision cascade prays a dominating role in preferential emission of the lighter Cu-63 atoms in the near-normal direction during low-bombarding-energy Cu-63-Cu-65 sputtering. (C) 2000 Elsevier Science B.V. All rights reserved.

Nonstoichiometric effects in the zero-fluence sputtering of a natural Cu(111) target (69.1% Cu-63, 30.9% Cu-65) irradiated with normally incident Ar+ ions from 50 to 1000 eV have been studied by use of a molecular dynamics (MD) simulation code. Calculations show that the isotopic ratios in the normal direction and at oblique angles, their difference, and the total isotopic ratio increase as the bombarding energy decreases. (C) 1999 Elsevier Science B.V. All rights reserved.

Under 2 keV Ar ion bombardment of a CuxNi1-x alloy, at high fluence and at low temperature, Cu and Ni sputtering yields, the total sputtering yield (Cu+Ni yields), and the sputtering yields from the first surface layer and from beneath this layer for Cu and Ni, have been separately calculated by an improved kinetic BIGS (bombardment-induced Gibbsian segregation) model. Calculations indicate that these sputtering yields are strongly dependant on the Cu (segregating species) bulk composition. A cause of the possible correlation between sputtering angular distribution and bulk composition of the segregating species is also analysed for the segregating system. (C) 1998 Elsevier Science Ltd. All rights reserved.

A static Monte Carlo simulation program has been used to study the influence of primary and secondary knock-on atoms on the angular distribution and the fractionation, for zero-fluence sputtering of Mo-92-Mo-100. At 10 keV Xe ion energy, calculations show that significant depth-dependent momentum asymmetry exists in the near-surface region, as in Refs. (L.P. Zheng, R.S. Li, M.Y.LI, Nucl. Instr, and Meth. B 100 (1995) 490; L.P. Zheng, M.Y. Li, Nucl. Instr. and Meth. B 114(1996) 28). The calculations also show that at the polar emission angle range between 0 degrees and 90 degrees the probabilities of the sputtered primary knock-on atoms for Mo-92 and Mo-100 are small (6.1% for Mo-92 and 6.6% for Mo-100), especially, between 0 degrees and 30 degrees they are very small (2.5% for Mo-92 and 2.8% for Mo-100). At 0.1 keV Ar ion energy, the calculations show that partial momentum flux ratios, for the primary and the secondary knock-on atoms, deviate far from one, through marker plane 1 (about an atomic layer distance from the surface). (C) 1998 Elsevier Science B.V. All rights reserved.

Under 1 keV Ar ion bombardment of Cu-Pt and Cu-Ni alloys at high fluence at low temperature, the depletion degree of the segregating species at the second surface layer, and the normalized sputtering yield ratios (non-segregating species/segregating species) in the near-normal direction (15 degrees) and at oblique angles (75 degrees), have been estimated by an improved kinetic BIGS (Bombardment-Induced Gibbsian Segregation) model. For both the bombarded Cu-Pt and the bombarded Cu-Wi alloys, calculations show that the depletion degree of the segregating species at the second surface layer is small when its bulk composition equals the extreme value, but this depletion degree becomes large when its bulk composition equals the intermediate value. Furthermore, the difference of the normalized sputtering yield ratio between 15 degrees and 75 degrees is small when the bulk composition of the segregating species equals the extreme value, but this difference becomes large when that of the segregating species equals the intermediate value.

In the sputtering of a 92 Mo 100 Mo target induced by 5 keV Ar ions, both static and dynamic Monte Carlo simulation programs have been used to estimate both the angular variations in isotopic enrichment from zero to high fluences, and the momentum flux ratios as a function of surface depth at the zero fluence. The calculations show that the isotopic ratio in the near-normal direction is positive and quite large at the zero fluence, then it decreases with increasing fluence. The calculations also show that the difference between the near-normal isotopic ratio and the oblique isotopic ratio is large and positive at both the zero and the high fluences, then this difference minimizes at a low fluence between the two fluence limits. The calculations indicate that depth-dependent momentum asymmetry significantly exists in the near-surface region.

We have investigated isotope effects in the sputtering of a Cu-63(69.1) Cu-65(30.9) mixture under 2 keV Xe ion bombardment, using a dynamic Monte Carlo program. For the Cu-63-Cu-65 sputtering, our calculations show that the isotope fractionation difference between small and large polar angles, delta(15 degrees)-(75 degrees), is great, both at zero fluence and at high fluence; then it minimizes at a low fluence (1.6 x 10(15) ions/cm(2)) between the two fluence limits. The calculations indicate that during prolonged bombardment, the isotopic angular pattern is a combination of primary and secondary effects. At low fluence, the secondary effects weaken the primary effects on the isotope fractionation difference, because the surface composition gradient of Cu-63 is positive. At high fluence, the secondary effects enhance the primary effects on the isotope fractionation difference, because this gradient is negative.

Evolutions of angular distributions and surface composition profiles of a sputtered Pt0.5Cu0.5 alloy were simulated under 1 keV Ar ion bombardment at normal incidence, with the help of a dynamic Monte Carlo program including preferential sputtering and BIGS (bombardment-induced Gibbsian segregation) processes etc. It is found during the PtCu alloy sputtering that the Cu enrichment in the near-normal direction is regularly transformed into the Pt one as the Ar ion fluence increases. Below a low fluence of about 1.7 ions/cm2, Cu is preferentially ejected in the near-normal direction; above 1.7 ions/cm2, on the other hand, Pt is preferentially ejected in the near-normal direction instead of Cu. Effects of preferential sputtering and BIGS processes on enrichment transformation between Cu and Pt elements in the near-normal direction are also discussed.

Under 1 keV Kr ion bombardment, both primary and secondary effects on B isotope sputtering have been investigated by means of a dynamic Monte Carlo program. It was found in these calculations that at both zero and high fluences the light isotope was preferentially ejected in the near-normal direction; between these two cases there was a low fluence (1.4 X 10(15) ions/cm2), at which the isotope fractionation was independent of the emission angle over nearly the whole angular range. The variation in the atomic ejection probabilities of B-10 and B-11 from beneath the topmost layer owing to surface composition changes may be a important cause of the above phenomena.

The properties of solid state nuclear track detectors (SSNTDs) for fast neutron measurements in the presence of high gamma radiation fields have been investigated. A comparative study of two different modes of fast neutron measurements based on SSNTDs is presented. In the internal radiator mode (IRM), the neutrons are detected due to the alpha particles and recoil nuclei created in materials, e.g. C and O present in the SSNTD itself by neutron interactions. In the external radiator mode (ERM), the SSNTD is covered by a front radiator consisting of 0.5 mm polyethylene, and the tracks are produced by recoil protons of the (n, p) converter reaction, and recoil particles and (n, α) reactions created in the detector itself by neutron interactions. In this work, we have used CSR (China Shanghai Resin) which is a polymeric track detector (Allyl diglycol carbonate) for measuring fast neutron fluences ranging from 10 6 to 10 11 n cm 2 . Results show that the CSR plastic detector can be used successfully for detecting 14 MeV neutron fluences in the range from 5 × 10 7 to 6 × 10 10 n cm 2 , and the detection efficiency of the CSR with polyethylene radiator is on the average 3.32×10 −5 tracks per neutron.

Momentum flux ratios (Mo-92/Mo-100) towards the surface and the bulk through marker planes have been studied by a static Monte Carlo simulation program for an isotopic mixture Mo-92(0).Mo-100(5)0.5 bombarded with 5 keV Xe ions. The calculations show that the momentum flux ratios in the cascade deviate far from one at different surface depths. The calculations also show that the zero-fluence isotopic ratio in the near-normal direction and its difference between small and large polar emission angles are positive.

The dynamic Monte Carlo computer simulation has been used to estimate the mean sputter depth and the surface composition gradient of binary component materials during prolonged ion bombardment. Calculation results indicate that for Pt0.5Cu0.5 sputtering, the Pt mean sputter depth is much larger than for Cu at high fluence, but the Pt mean sputter depth approximates Cu at the zero fluence (in the low fluence limit). For B-10(0.2) B-11(0.8) sputtering the B-10 mean sputter depth approximates the B-11 one, not only at the zero fluence but also at high fluence. The calculation results also indicate that the mean sputter depth depends on the surface composition gradient during prolonged ion bombardment. This dependence should be deeply concerned in high fluence sputtering and high fluence implantation areas.

[zheng, li-ping; zhu, zhi-yuan; li, yong; yan, long] chinese acad sci, shanghai inst appl phys, shanghai 201800, peoples r china. [zheng, li-ping] chinese acad sci, int ctr mat phys, shenyang 110016, peoples r china.;li, y (reprint author), chinese acad sci, shanghai inst appl phys, pob 800 204, shanghai 201800, peoples r china;liyong@sinap.ac.cn

[Zheng, Li-Ping; Zhu, Zhi-Yuan; Li, Yong] Chinese Acad Sci, Shanghai Inst Appl Phys, Shanghai 201800, Peoples R China. [Zheng, Li-Ping] Chinese Acad Sci, Int Ctr Mat Phys, Shenyang 110016, Peoples R China. [Goodman, Frank O.] Univ Waterloo, Dept Appl Math, Waterloo, ON N2L 3G1, Canada.;Li, Y (reprint author), Chinese Acad Sci, Shanghai Inst Appl Phys, POB 800-204, Shanghai 201800, Peoples R China;liyong@sinap.ac.cn